EP0855280A2 - Record head - Google Patents
Record head Download PDFInfo
- Publication number
- EP0855280A2 EP0855280A2 EP98300566A EP98300566A EP0855280A2 EP 0855280 A2 EP0855280 A2 EP 0855280A2 EP 98300566 A EP98300566 A EP 98300566A EP 98300566 A EP98300566 A EP 98300566A EP 0855280 A2 EP0855280 A2 EP 0855280A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- ink
- slit
- record
- photoconductive film
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
- B41J2002/061—Ejection by electric field of ink or of toner particles contained in ink
Definitions
- the present invention relates to a record head used in a record device for providing output picture on record paper capable of dealing with a wide variety of needs of industries ranging from the printing industry where high speed output of high quality picture is requested, the printer industry based on business or personal request to the electric appliance industry where general output devices and the like at low price using various kinds and uses of record paper are requested.
- a record head having an ink jet injection port 101 formed in a slit-like shape, an upper plate 102 and a lower plate 103 for forming the ink injection port 101, a record electrode 104 arranged on the lower plate 103 by a unit of a record pixel, an opposed electrode 105 arranged opposedly to the ink injection port 101, a record medium 110 moving along the opposed electrode 105 and a drive power source 106 for supplying voltage to a selected electrode of the record electrode 104, ink 108 is filled in the ink injection port 101 and a voltage pulse 107 is applied between the record electrode 104 and the opposed electrode 105 by which the ink 108 is injected and flown ink 109 is adhered and permeated onto the record medium 110 whereby desired output print or picture is obtained.
- the resolution can be prevented from being restricted by the nozzle and further, cleaning of the ink jet port 101 can be facilitated.
- a plurality of the ink injection ports 101 are used and the inks 108 having different colors are injected into the respective ink injection ports 101 by which color output printing can easily be provided.
- the ink jet recording system is classified into a continuous type and an on-demand type.
- the continuous type although the record speed is high, the device is difficult to simplify due to recovery of unnecessary ink or the like whereas according to the on-demand type, although the constitution of the device is simplified, the record speed is difficult to accelerate.
- a record unit in which highly fine and high quality printing is carried out at high speed and output printing in a noncontact state and where shape of a record medium is not selected can be carried out, and a record device using the record unit, a record unit and a record head used for the record device.
- a record head having a transparent electrode formed on a substrate, a photoconductive film formed on the transparent electrode, means for supplying ink on the photoconductive film, a slit plate installed with a slit for controlling injection of the ink and an opposed electrode in this order, the slit plate and the opposed electrode being arranged with a gap therebetween sufficient for incorporating a record medium, and at least having a power source for applying a voltage between the transparent electrode and the opposed electrode and light irradiating means for supplying light in correspondence with a desired pixel to the photoconductive film in a form of a pulse.
- a record head having a transparent electrode formed on a substrate, a photoconductive film formed on the transparent electrode, means for supplying ink on the photoconductive film, a slit plate installed with a slit for controlling injection of the ink and an opposed electrode in this order, the slit plate and the opposed electrode being arranged with a gap therebetween sufficient for incorporating a record medium, and at least having a power source for applying a voltage between the transparent electrode and the opposed electrode and light irradiating means for irradiating light in correspondence with a desired pixel to the photoconductive film, wherein an ink storage groove for temporarily storing the ink is formed on the substrate along a longitudinal direction of the slit and the ink storage groove(s) are disposed in an ink chamber formed between the substrate and the slit plate and disposed at an upper side or a lower side or both sides of the slit in a direction of a plane of the substrate.
- Fig. 1 is an explanatory view showing the constitution of a record head according to a first example of the present invention.
- Fig. 2 is an explanatory view showing the constitution of a record head according to a second example of the present invention.
- Fig. 3 is an explanatory view showing the constitution of a record head according to a third example of the present invention.
- Fig. 4 is an explanatory view showing the constitution of a record head according to a fourth example of the present invention.
- Fig. 5 is a disassembled perspective view showing the constitution of a head unit of the record head according to the fourth example of the present invention.
- Fig. 6 is a disassembled perspective view showing the constitution of the record head according to the fourth example of the present invention and its peripheral mechanism.
- Fig. 7 is an explanatory view showing the constitution of a record head according to a fifth example of the present invention.
- Fig. 8 is a block diagram showing the constitution of a recording device using the record head of the present invention.
- Fig. 9 is an explanatory view showing a first embodiment of a record head of the present invention.
- Fig. 10 is an explanatory view showing a record head of a conventional slit jet system.
- Fig. 9 shows a first embodiment of a record head according to the present invention.
- a head unit 54 of the record head is constituted by a transparent substrate 58, a transparent electrode 2 formed on the transparent substrate 58 and a photoconductive film 4 formed on the transparent electrode 2, further, a slit plate 8 is installed on the photoconductive film 4 via a spacer 55 for forming an ink chamber 56 and a slit 57 for controlling injection of the ink 6 is formed at the slit plate 8. Further, ink supplying means 50 for supplying the ink 6 to the ink chamber 56 on the photoconductive film 4 is constituted at the head unit 54.
- an opposed electrode 1 is installed around the head unit 54 on the side of the slit plate 8 and the opposed electrode 1 is arranged such that a gap sufficient for incorporating a record medium 10 is formed between the opposed electrode 1 and the slit plate 8.
- Paper feeding means (not illustrated) for supplying the record medium 10 without being brought into contact with the slit plate 8
- a power source 3 for applying voltage between the transparent electrode 2 and the opposed electrode 1
- light irradiating means 5 for supplying light in correspondence with a desired picture pixel to the photoconductive film 4 in a form of a pulse is installed on the rear face side of the transparent substrate 58.
- the record head described in the first embodiment of the present invention sufficiently resolves the above-described problems. That is, it is easy to promote the resolution since it has no record electrode. Further, the record head has a feature in which there causes no discharge phenomenon between record electrodes since it has no record electrode and it is easy to optimize the ink characteristic and control applied voltage and timing thereof.
- the frequency of driving the record head described in the first embodiment is significantly dependent on the refilling rate of ink and the record speed is restricted thereby.
- the capacity of ink in the ink chamber must be enlarged and a mechanism capable of supplying ink sufficiently and at high speed is needed at the slit portion.
- the expansion of the ink capacity is achieved by increasing, for example, the height of the ink chamber, that is, a distance of the gap between the photoconductive film face on the substrate and the slit plate
- the injected ink amount is simultaneously increased and further, the amount of consumption of ink is increased and accordingly, as a result, the refilling rate of ink is not accelerated considerably.
- the resolution is obliged to lower by an increase in the amount of injecting ink and since the amount of injecting ink is increased, energy necessary for injection, that is, a value of voltage applied between the both electrodes must be increased or time of
- the ink chamber is formed thinly with a wide area in the head, when the head is not used in a long period of time, the ink filled in the ink chamber is liable to evaporate by which a solidified component of ink such as a pigment or the like adheres to the slit portion and the slit portion is clogged, further, the direction of injecting ink is varied thereby, which may cause dimmed portions or nonuniformity of dots and print quality may be deteriorated.
- the record head is constituted by a line head
- the amount of consumption of ink per unit time period is increased since the slit width as a injecting portion is significantly wider than a serial head. Therefore, these problems are revealed significantly in the case of a line head.
- the ink is flown by using electrostatic force by applying high voltage between the electrodes and therefore, when impurities or the like having high conductivity are mixed in the ink, the discharge phenomenon may be caused.
- a record head having a transparent electrode formed on a substrate, a photoconductive film formed on the transparent electrode, means for supplying ink on the photoconductive film, a slit plate installed with a slit for controlling injection of the ink and an opposed electrode in this order, the slit plate and the opposed electrode being arranged with a gap therebetween sufficient for incorporating a record medium, and at least having a power source for applying a voltage between the transparent electrode and the opposed electrode and light irradiating means for supplying light in correspondence with a desired pixel to the photoconductive film in a form of a pulse wherein an ink storage groove for temporarily storing the ink is formed on the substrate along a longitudinal direction of the slit and the ink storage groove(s) are disposed in an ink chamber formed between the substrate and the slit plate and disposed at an upper side or a lower side or both sides of the slit in a direction of a plane of the
- the record head having the above-described first constitution operates as follows.
- the record head of this constitution in the first constitution of the record head, is provided with a member having ink permeable fine pores in the ink storage groove.
- the record head of the above-described second constitution operates as follows.
- the ink to be refilled is supplied at high speed to the inside of the ink chamber, that is, the slit portion by a constant amount after passing through the material having fine pores provided in the ink storage groove.
- the record head of this constitution is provided with ink accelerating means for accelerating further flown ink.
- the record head of the above-described third constitution operates as follows.
- the record head described in the first, or the second, or the third constitution is constituted in a line shape in correspondence with the print width of the record medium.
- the record head of the above-described fourth constitution operates as follows.
- the state where electricity is conducted between the ink and the transparent electrode is produced at the irradiated region of the photoconductive film, electric charge is charged to inside of the ink on the photoconductive film, the ink is flown toward the side of the opposed electrode by receiving Coulomb's force, the flown ink is moved, permeated and adhered to the record medium on the opposed electrode and therefore, one line region of desired picture pixels are provided on the record medium.
- the ink to be refilled is supplied swiftly from the ink storage groove to the inside of the ink chamber, that is, the slit portion.
- a fifth constitution of the record unit of the present invention a plurality of the record heads having one of the first through the fourth constitutions are used and means for supplying inks having different colors to the respective record heads are provided.
- the record unit having the above-described sixth constitution operates as follows.
- Fig. 1 is an explanatory view showing the first constitution of a record head according to the present invention.
- the record head is constituted by the head unit 54, the ink supplying means 50 for supplying a necessary amount of ink to the head unit 54, the light irradiating means 5 arranged on the right side (hereinafter, rear face side) of the head unit 54 for irradiating light to the head unit 54, the opposed electrode 1 arranged on the left side (hereinafter, opposed face side) of the head unit 54 and the power source 3 for applying voltage between the opposed electrode 1 and an electrode in the head unit 54.
- Numeral 58 designates a transparent substrate and the transparent substrate 58 is formed by a light transmitting material of glass, acrylic resin, plastic or the like for transmitting wavelength of light from the light irradiating means 5 arranged on the rear face side. Further, the transparent electrode 2 and the photoconductive film 4 are successively laminated on a face of the transparent substrate 58 on the opposed face side and the slit plate 8 is formed thereon via the spacer 55.
- the spacer 55 is disposed in the upward and downward directions and transverse directions from the slit 57 such that the slit 57 in an elongated hole shape formed on the slit plate 8 is not closed and further, ink is not leaked and by constituting in this way, there is formed a space of the ink chamber 56 that is hermetically sealed at other than the opening of the slit 57.
- the ink storage groove 53 is formed in the ink chamber 56 on the transparent substrate 58 and the depth of the ink storage groove 53 is set to be sufficiently deeper than that of the ink chamber 56. Further, the ink storage groove 53 is formed to dispose on the upper side or the lower side of the slit 57 such that the ink storage groove 53 is not opposed to the position of opening the slit 57 in the slit plate 8.
- an inorganic conductor of a photoconductive single crystal material of Se group, CdS group, ZnO group, BSO (Bi 12 SiO 20 ) or the like, hydrogenerated amorphous silicon of i type, pi type, pin type or the like, or a lamination type organic photoconductor such as CTL/CGL or the like can be used.
- the photoconductive film 4 the photoconductivity is important and it is preferable that potential difference of surface potential caused by attenuation of light is large.
- the dark resistance of the inorganic photoconductor or the organic photoconductor falls in a range of 10 13 through 10 14 ⁇ . cm and the resistance value is lowered to 10 10 through 10 11 ⁇ .
- the dark resistance falls in a range of 10 9 through 10 11 ⁇ . cm and the resistance value can be lowered to 10 4 through 10 6 ⁇ . cm by irradiating light to the photoconductive film 4 by which large surface potential difference can be ensured.
- the optimum film thickness is 20 ⁇ m or lower, preferably, about 10 ⁇ m.
- hydrogenerated amorphous silicon of i type where impurity elements are removed it is preferable to use hydrogenerated amorphous silicon of i type where impurity elements are removed.
- ITO Indium-Tin-Oxide
- a conductive high molecular material a metal thin film having a thinness sufficient for passing light (for example, Al thin film having a film thickness of 0.03 ⁇ m or the like), or ZnO, or SnO 2 or compounds of these can be used.
- a material having excellent conductivity such as aluminum, copper, gold or the like can be used.
- Numeral 52 designates an ink tank for storing an supplying ink and ink filled in the ink tank 52 is supplied to the ink chamber 56 or the ink storage groove 53 of the record head unit 15 via an ink supply path 51 of a pipe or the like.
- the ink 6 is supplied firmly to the ink chamber 56 under the slit 57 or the ink storage groove 53 by setting the interface of ink of the ink tank 52 higher than the positions of the ink chamber 56 and the ink storage groove 53.
- the ink supplying means 50 may be constituted integrally with the head unit 54.
- a semiconductor laser can be used and laser beam is irradiated by the light irradiating means 5 in an arrow mark 7 direction from the rear face side of the transparent substrate 58 to a position on the photoconductive film 4 in correspondence with a desired picture pixel. Further, the irradiated light reaches the photoconductive film 4 after transmitting through the transparent substrate 58 and the transparent electrode 2. Thereby, the resistance value is lowered only at the irradiated desired picture pixel region on the photoconductive film 4.
- the photosensitivity can be promoted by promoting the light attenuation rate of the photoconductive film 4 by matching the oscillation wavelength of the laser beam with the absorption coefficient of the photoconductive film 4 in respect of the oscillation wavelength.
- the intensity of irradiated light, the shape of focus light spot and the like of laser beam irradiated from a laser oscillation device of a semiconductor laser or the like are optimized by an optical lens or the like and the laser beam can be constituted by a laser beam scanning mechanism composed of a polygonal mirror and the like at the light irradiating means 5.
- laser beam is irradiated from the light irradiating means 5 and therefore, picture can be formed on the photoconductive film 4 at a position in correspondence with a desired picture pixel in a noncontact state and at high speed.
- a semiconductor laser is used as a light emitting source of the light irradiating means 5, the present invention is not limited thereto but He-Ne laser, a semiconductor laser array, an LED array, a halogen lamp or the like can be used sufficiently as the light emitting source.
- a light shutter array or a liquid crystal television set may be used in place of the above-described laser scanning optical system.
- slit light exposure may be performed by an analog optical system such as a copier and light may be irradiated directly to the head unit 54 via an optical system.
- the opposed electrode 1 comprises a conductive material and is arranged on the side of opposing the head unit 54 via a clearance of about 0.2 through 1 mm from the slit plate face of the head unit 54.
- the side of the opposed electrode 1 is connected to the positive pole of the power source 3 and the side of the transparent electrode 2 in the head unit 54 is connected to the negative side thereof, respectively, in printing, constant voltage is applied between the both electrodes by the power source 3 and electric field is generated at the clearance between the both electrodes.
- the shape of the opposed electrode 1 is constituted by a plane, it is preferable to concentrate the electric field by sharpening the opposed electrode face, constituting a shape having a radius of curvature or the like and in this way, energy necessary for injection of ink, that is, applied voltage or applied pulse can be reduced.
- the photoconductive phenomenon is caused and photocurrent is flown at the light irradiated portion inside of the photoconductive film 4. That is, carriers are formed at the irradiated region of the photoconductive film 4 and transferred by the external electric field, as a result, the impedance is lowered and the photocurrent is flown.
- the negative pole is connected to the side of the transparent electrode 2 and accordingly, electrons emerge on the ink side at the light irradiated portion, however, this is because the charge characteristic of the ink according to the embodiment-is defined as negative and the charge characteristic is not particularly limited thereto, although it is necessary to correspond to the charge characteristic of the ink.
- the ink 6 and the transparent electrode 2 are brought into a conductive state and negative charge is charged to inside of the ink 6 having high insulating performance on the photoconductive film 4. Further, the ink is attracted to the record medium 10 on the opposed electrode 1 by receiving Coulomb's force caused by the electric field developed between the transparent electrode 2 and the opposed electrode 1 and the flown ink 12 is injected from the slit 57 to the side of the opposed electrode 1 and is adhered to the record medium.
- Fig. 2 is an explanatory view showing the second constitution of a record head according to the present invention.
- the record head is constituted by the head unit 54, the ink supplying means 50 for supplying a necessary amount of ink to the head unit 54, the light irradiating means 5 arranged on the rear face side of the head unit 54 for irradiating light to the head unit 54, the opposed electrode 1 arranged on the opposed face side of the head unit 54 and the power source 3 for applying voltage between the opposed electrode 1 and the electrode in the head unit 54.
- Numeral 58 designates the transparent substrate and the transparent substrate 58 is formed by a light transmitting material of glass, acrylic resin, plastic or the like for transmitting wavelength of light from the light irradiating means 5 arranged on the rear face side. Further, the transparent electrode 2 and the photoconductive film 4 are successively laminated on the face of the transparent substrate 58 on the opposed face side and the slit plate 8 is formed thereon via the spacer 55.
- the spacer 55 is arranged on the upper side, the lower side and in the lateral directions of the slit 57 such that the slit 57 having an elongated hole shape formed on the slit plate 8 is not closed and ink is not leaked and by constituting in this way, a hermetically sealed space of the ink chamber 56 is formed at other than the opening of the slit 57.
- the ink storage groove 53 is formed at inside of the ink chamber 56 on the transparent substrate 58 and the depth of the ink storage groove 53 is set sufficiently deeper than that of the ink chamber 56.
- the ink storage groove 53 is formed to dispose on the upper side or the lower side of the slit 57 such that the ink storage groove 53 is not opposed to the position of opening the slit 57 in the slit plate 8.
- a porous material 65 where fine pores are formed is embedded in the ink storage groove 53 and the porous material 65 is formed by a foaming material comprising polyurethane, polyethylene, rubber, silicone rubber or the like.
- Numeral 52 designates an ink tank for storing and supplying ink and ink filled in the ink tank 52 is supplied to the ink storage groove 53 of the record head unit 54 via the ink supply path 51 of a pipe or the like. Further, the ink 6 in the ink storage groove 53 receives flow resistance by interposing the porous material 65 and the constant amount of ink is supplied to the ink chamber 56. The amount of ink supplied to the ink chamber 56, that is, the portion of the slit 57 can freely be controlled by the size of the pore and a number of pores per unit volume of the porous material 65.
- the ink 6 is firmly supplied to the ink chamber 56 under the slit 57 or the ink storage groove 53 by setting the interface of ink of the ink tank 52 higher than the positions of the ink chamber and the ink storage groove 53.
- the ink supplying means 50 may be constituted integrally with the head unit 54.
- the light irradiating means 5 similar to Example 1, a semiconductor laser can be used and laser beam from the light irradiating means 5 is irradiated in the arrow mark 7 direction from the rear face side of the transparent substrate 58 to the position on the photoconductive film 4 in correspondence with a desired picture pixel. Further, the irradiated light reaches the photoconductive film 4 by transmitting through the transparent substrate 58 and the transparent electrode 2. Thereby, a resistance value of only the irradiated desired picture pixel region is lowered on the photoconductive film 4.
- the opposed electrode 1 comprises a conductive material and is arranged on the opposed face side of the head unit 54 via a clearance of about 0.2 through 1 mm from the slit plate face of the head unit 54.
- the side of the opposed electrode 1 is connected to the positive pole of the power source 3 and the side of the transparent electrode 2 in the head unit 54 is connected to the negative pole thereof, respectively, constant voltage is applied between the both electrodes by the power source 3 in printing and electric field is generated at. the clearance between the both electrodes.
- the photoconductive phenomenon is caused and photocurrent is flown at the light irradiated portion inside of the photoconductive film 4. That is, carriers are formed at the irradiated region of the photoconductive film 4 and transferred by the external electric field, as a result, the impedance is lowered and the photocurrent is flown.
- the ink 6 and the transparent electrode 2 are brought into a conductive state, and negative charge is charged locally in the ink 6 having high insulating performance on the photoconductive film 4. Further, the ink is attracted to the record medium 10 on the opposed electrode 1 by receiving Coulomb's force by electric field developed between the transparent electrode 2 and the opposed electrode 1 and the flown ink 12 is injected to the side of the opposed electrode 1 from the slit 57 and adhered to the record medium.
- the ink is supplied always stably to the slit and the. stable recording operation can be performed by firmly restraining the discharge phenomenon which may be caused between the opposed electrode and the transparent electrode under application of voltage by removing impurities in the ink.
- Fig. 3 is an explanatory view showing the third constitution of a record head according to the present invention.
- the record head is constituted by the head unit 54, the ink supplying means 50 for supplying a necessary amount of ink to the head unit 54, the light irradiating means 5 arranged on the rear face side of the head unit 54 for irradiating light to the head unit 54, the opposed electrode 1 arranged on the opposed face side of the head unit 54, the power source 3 for applying voltage between the opposed electrode 1 and the electrode in the head unit 54 and accelerating means for accelerating the injected ink in the flying direction.
- Numeral 58 designates the transparent substrate and the transparent substrate 58 is formed by alight transmitting material of glass, acrylic resin, plastic or the like for transmitting wavelength of light from the light irradiating means 5 arranged on the rear face side. Further, the transparent electrode 2 and the photoconductive film 4 are successively laminated on the face of the transparent substrate 58 on the opposed face side and the slit plate 8 is formed thereon via the spacer 55.
- the spacer 55 is arranged on the upper side, the lower side and in the lateral directions of the slit 57 such that the slit 57 having an elongated hole shape formed on the slit plate 8 is not closed and ink is not leaked and by constituting in this way, a hermetically sealed space of the ink chamber 56 is formed at other than the opening of the slit 57.
- the ink storage groove 53 is formed at inside of the ink chamber 56 on the transparent substrate 58 and the depth of the ink storage groove 53 is set sufficiently deeper than that of the ink chamber 56. Further, the ink storage groove 53 is formed to dispose on the upper side or the lower side of the slit 57 such that the ink storage groove 53 is not opposed to the position of opening the slit 57 in the slit plate 8.
- Numeral 52 designates the ink tank for storing and supplying ink and ink filled in the ink tank 52 is supplied to the ink storage groove 53 or the ink chamber 56 of the record head unit 54 via the ink supply path 51 of a pipe or the like.
- the ink 6 is supplied firmly to the ink chamber 56 under the slit 57 or the ink storage groove 53 by setting the interface of ink of the ink tank 52 higher than the positions of the ink chamber 56 and the ink storage groove 53.
- the ink supplying means 50 may be constituted integrally with the head unit 54.
- the light irradiating means 5 similar to Example 1, a semiconductor laser can be used and laser beam from the light irradiating means 5 is irradiated in the arrow mark 7 direction from the rear face side of the transparent substrate 58 to the position on the photoconductive film 4 in correspondence with a desired picture pixel. Further, the irradiated light reaches the photoconductive film 4 after transmitting through the transparent substrate 58 and the transparent electrode 2. Thereby, the resistance value of only the irradiated desired picture pixel region is lowered on the photoconductive film 4.
- the opposed electrode 1 comprises a conductive material and is arranged on the opposed face side of the head unit 54 via a clearance of about 0.2 through 1 mm from the slit plate face of the head unit 54.
- the side of the opposed electrode 1 is connected to the positive pole of the power source 3 and the side of the transparent electrode 2 in the head unit 54 is connected to the negative pole thereof, respectively, constant voltage is applied between the both electrodes by the power source 3 in printing and electric field is generated at the clearance between the both electrodes.
- the accelerating means 14 is arranged between the slit plate 8 and the opposed electrode 1.
- the accelerating means 14 is fabricated by a material having excellent conductivity of aluminum, copper, gold or the like and may be of a condenser fabricated by a set of flat plates, or a member having a shape of a closed tube such as a cylinder or the like may be used.
- the speed of the flown ink 12 is accelerated by the accelerating means 14 of the example and further, the amount of energy supplied to the photoconductive film 4 can be reduced by controlling a voltage value applied for flying the ink 6 and the light energy provided from the light irradiating means 5. Further, according to the accelerating means 14, voltage is applied to the accelerating means 14 from the electrode of the power source 3 on the side of the opposed electrode 1 via a resistor in this example.
- application of potential to the accelerating means 14 is not limited thereto but, for example, the potential difference between the transparent electrode 2 and the accelerating means 14 can be made larger than the potential difference between the transparent electrode 2 and the opposed electrode 1. This is determined by the amount of the flown ink 12, a distance between the accelerating means 14 and the surface of the ink 6 or the like.
- the ink 6 can be flown only by the accelerating means 14.
- the photoconductive phenomenon is caused and photocurrent is flown at the light irradiated portion inside of the photoconductive film 4. That is, carriers are formed at the irradiated region of the photoconductive film 4 and transferred by the external electric field, as a result, the impedance is lowered and the photocurrent is flown.
- Fig. 4 is an explanatory view showing a record head of a line shape that is the fourth constitution according to the present invention.
- Fig. 5 is a disassembled perspective view of the head unit 54 of the record head and
- Fig. 6 is a perspective view showing the constitution of the record head and its periphery.
- Numeral 58 designates the transparent substrate that is longer than the length of the record medium 10 in the width direction (main scanning direction), a light transmitting material of acrylic resin, plastic or the like for transmitting wavelength of light from the light irradiating means 5 arranged on the rear face side of the substrate is used in the transparent substrate 58 and the ink storage groove 53 and the ink chamber 58 (The notation is not indicated in Fig. 4 and Fig. 5 to avoid complication of the drawings. Refer to Fig. 1 through Fig. 3 for details.) are formed by injection molding and the shape of spacer is integrally formed.
- the transparent electrode 2 and the photoconductive film 4 are successively laminated on the face of the transparent substrate 58 on the opposed face side by using screen printing or the like.
- the slit plate 8 having a slit opening portion of about the width of the record medium 10 is constituted on the opposed face side of the transparent substrate 58 such that a recessed portion where the ink storage groove 53 and the ink chamber 56 are formed, is closed. Thereby, the ink storage groove 53 and the ink chamber 56 are formed as a space hermetically sealed at other than the opening portion of the slit 57.
- the photoconductive film 4 is not laminated at the right end portion of the transparent substrate 58 in order to form a lead-out portion of the electrode and the transparent electrode 2 is in an exposed state and an electrode line of a flexible substrate 70 or the like is press-contacted, bonded by conductive bonding or soldered to the portion thereby providing an electrode contact.
- a gap portion between the transparent substrate 58 and the slit plate 8 produced when the slit plate 8 is attached, is filled with a sealing member 71 or an adhesive agent by which the portion where the transparent electrode 2 is exposed is prevented from being brought into contact with ink.
- ink supply holes 60 for flowing ink from the ink supply path 51 into the record head penetrate the bottom portion of the ink storage groove 53 of the transparent substrate 58 to the rear face side.
- the ink supply holes 60 are provided at two locations on the both ends of the transparent substrate 58 in the longitudinal direction and one of them constitutes a hole for air vent such that bubbles are not stored in the ink storage groove 53 and the ink chamber 56 when ink is injected.
- a reinforcing plate 59 is disposed on the rear face side of the transparent substrate 58 and the ink tank 52 is disposed on the rear face side of the reinforcing plate 59.
- the ink supply paths 51 are provided in the reinforcing plate 59 at positions the same as those of the ink supply holes 60 provided to the transparent substrate 58 and are formed to penetrate projected portions on the rear face side of the reinforcing plate 59. Further, by inserting the projected portions into the ink tank 52, ink in the ink tank 52 is flown through the ink supply paths 51.
- an adhesive agent or the like may be filled between the ink supply holes 60 and the ink supply paths 51 and between the ink supply paths 51 and the ink tank 52 such that ink is not leaked when the head is formed, it is preferable to insert sealing members of O rings, oil seals or the like between the respective substrates.
- the reinforcing plate 59 is provided simply for reinforcing the transparent substrate 58 and reducing warp thereof and fixing the ink tank 52 provided on the side of the reinforcing plate opposed to the substrate and is not necessarily needed when the above-described points are satisfied by the transparent substrate 58.
- a polygonal scanner 61 using a semiconductor laser that is the light irradiating means is disposed on the rear face side of the head unit 54 and laser beam condensed at the slit position of the head unit 54 via a condensing optical system or the like, is irradiated while being scanned in the slit direction.
- the opposed electrode 1 in a drum shape comprising a conductive material is arranged on the opposed face side of the head unit 54.
- the drum main body is disposed by maintaining a constant distance from the face of the slit 57 of the head unit 54 such that the drum main body is not brought into contact with the face of the slit 57 and is pivotable in the clockwise direction, that is, paper feeding direction by a drive system, not illustrated.
- electric contact is provided by bringing an elastic thin plate electrode in press-contact with the periphery of the drum or the axial end (not illustrated) and the electrode is connected to the power source 3.
- the paper feeding means 11 is constituted by paper supplying means 62 and paper transferring means 63 as shown by Fig. 4.
- the paper feeding means 62 is arranged on the upstream side of the paper feeding means 11, the paper feeding means 62 is constituted by a drive roller and a rotatable pinch roller and the pinch roller is brought into press-contact with the drive roller in a rotatable state.
- Paper guides 64 comprising an insulating material are arranged around the periphery of the drum of the opposed electrode 1 and guide the record medium 10 transferred by the paper feeding means 62 such that the record medium 10 is transferred along the shape of the drum.
- the drum of the opposed electrode 1 is pivoted by a drive system, not illustrated, with a motor speed of which can be controlled such as a pulse motor or a DC servo motor or the like as a drive source via a gear wheel train and a pulley belt drive system and an elastic pinch roller of rubber, urethane or the like is brought into press-contact with the lower end of the drum rotatably.
- a mechanism for transferring the record medium 10 supplied from the paper feeding means 62 by driving the drum of the opposed electrode 1, is constituted and the portion constitutes the paper transferring means 63.
- the record medium 10 is supplied to the side of the opposed electrode 1 by the paper feeding means 62, made to pass through a very small clearance between the drum peripheral face of the opposed electrode 1 and the paper guides and transfer to the paper transferring means 63 along the drum peripheral face of the opposed electrode 1.
- the front end of the record medium 10 is inserted between the opposed electrode 1 and the pinch roller and heading of record position is carried out by detecting position by using an edge sensor or the like and the transfer of the record medium 10 is once stopped.
- the record medium 10 is transferred to a second line by driving the paper transferring means 63, that is, the drum of the opposed electrode 1 in the sub scanning direction by a dot pitch having necessary resolution.
- the ink storage groove may naturally be disposed on the lower side of the slit or both on the upper and the lower sides.
- the ink storage groove may be formed such that the portion of the slit is avoided, that is, at a position not blocking light from the light irradiating means.
- Fig. 7 is an explanatory view showing the sixth constitution of a record head 71 according to the present invention.
- Fig. 7 four of the record heads 71 each in a line shape in correspondence with the width of print of the record medium 10 as shown by Example 6, are laminated vertically and inks 6 of yellow (Y), magenta (M), cyan (C) and black (Bk) are supplied from the upper portions of the respective record heads 71 to the record heads 71.
- Y yellow
- M magenta
- C cyan
- Bk black
- a state where high voltage is applied between the individual transparent electrodes 2 and the opposed electrode 1 is produced, light is irradiated in an arrow mark 7 direction from the side of the transparent electrode 2 of the yellow ink record head 71 to the photoconductive film 4 by the light irradiating means 5, the resistance value of the photoconductive film 4 at the irradiated region is lowered and photocurrent is flown.
- the magenta ink record head 71 is moved in the arrow mark 17 direction, a desired pixel of cyan ink is provided on the record medium 10 in 1 line region by the cyan ink record head 71 through the above-described recording procedure.
- the cyan ink record head 71 is moved in the arrow mark 17 direction, the desired pixel of black ink is provided on the record medium 10 in 1 line region by the black ink record head 71 through the above-described recording procedure.
- the record medium 10 is moved in a 1 line arrow mark 19 direction by paper feeding means, not illustrated, the four record heads 71 are driven in an arrow mark 18 direction back to the home positions, the above-described procedure is repeated and the desired color pixels for each picture is provided on the record medium 10.
- the inks 6 are constituted by 4 kinds, by increasing the number of the record heads 71 and supplying individually the inks 6 of multiple colors, highly fine output print or picture of full color with no restriction in the color of print is provided.
- the present invention is not limited thereto but, for example, a plurality of serial heads may be arranged and the main scanning direction may be controlled respectively and independently from each other.
- Fig. 8 is an explanatory view showing the constitution of the record device using each of the record heads 71 described in the first through the fifth examples of the present invention.
- a record device 30 inputs picture data 29 from an outside device 28, picture modifying processing or pattern recognition is carried out at a picture processing circuit 25, data transformation is carried out for each pixel and picture pixel data 31 is outputted.
- the picture pixel data 31 is transferred to inside of a record unit 24 in synchronism with a trigger signal 36 from a controller 26 and a flown ink 32 in correspondence with the picture pixel data 31 is adhered and transcribed from the record unit 24 to the record paper 10 that is the record medium.
- synchronization of the flown ink 32 and the record paper 10 is carried out by outputting a control signal 33 from the controller 26 to paper feeding means 11. Further, a voltage value 34 in the record unit 24 is set to a power source unit 27 from the controller 26 and voltage 35 is supplied from the power source unit 27 to the record unit 24. Further, an output of a light control signal 37 of a light source irradiation light intensity and an irradiated pulse width in the record unit 24 or a drive processing signal 38 of an optical part or the like is controlled by the controller 26 whereby dots formed on the record paper 10 are controlled.
- the record unit 24 of the present invention as the record device 30, can perform highly fine 'printing with high quality at high speed and can provide output print in a noncontact state without selecting the shape of the record medium.
- an ink storage groove for temporarily storing ink on the substrate is formed along the longitudinal direction of the slit, the ink storage groove is disposed at inside of an ink chamber formed between the substrate and the slit plate and is disposed on the upper side, or the lower side, the both sides of the slit in the direction of the face of the substrate and accordingly, the following effects are achieved.
- a sufficient amount of ink can be supplied at high speed to the slit portion after flying ink in printing and accordingly, the drive frequency of the record head can be accelerated. That is, the record speed as the device can be accelerated. Further, thereby, the discharge phenomenon between the opposed electrode and the slit which may occur by deficiency in supplying ink can be avoided.
- the ink injecting portion of the record head is provided with a slit shape and accordingly, different from a record head having a conventional nozzle shape, ink is communicated in one channel by the ink chamber and the ink storage groove and accordingly, ink is brought into the state of being difficult to dry. Further, the ink supply groove is provided at the vicinity of the slit portion in the record head and therefore, ink is filled always sufficiently in the slit portion. Therefore, ink clogging of the slit portion caused by evaporation or solidification of ink is difficult to occur and stable high quality recording can be performed.
- the ink supply amount is increased by deepening the groove in the depth direction according to the ink supply groove in the record head and therefore, the ink chamber is not expanded in the direction of the plane of the substrate, the head can be constituted while saving space and particularly in forming the device such that colors can be constituted by arranging the record heads of the respective colors, the device can be downsized.
- a proper supply amount of ink can be controlled by flow resistance which ink receives in passing through the member.
- Impurities in ink at very fine pores can be removed by passing the ink through the member by which the discharge phenomenon caused by clogging of ink at the slit or the ink path or by mixing impurities can be prevented.
Abstract
A record head is constituted such that an ink storage groove for temporarily
storing ink on a substrate is formed along a longitudinal direction of a slit, the ink
storage groove is disposed in an ink chamber formed between the substrate and the slit
plate and is disposed at an upper side, or a lower side both sides of the slit in a direction
of a face of the substrate by which a sufficient amount of ink is stably supplied to the slip
portion at high speed and prevention of discharge phenomenon and acceleration of the
record speed are achieved. Also, a record head having a photoconductive film formed
on a transparent electrode, means for supplying ink on the photoconductive film, and
light irradiating means for supplying light on to the photoconductive film in a form of a
pulse and in correspondence with a desired pixel.
Description
The present invention relates to a record head used in
a record device for providing output picture on record paper
capable of dealing with a wide variety of needs of industries
ranging from the printing industry where high speed output of
high quality picture is requested, the printer industry based
on business or personal request to the electric appliance
industry where general output devices and the like at low price
using various kinds and uses of record paper are requested.
According to a slit jet system that is a kind of a
conventional electrostatic attraction system in ink jet
recording (Susumu Ichinose et al: "A slit jet recording system",
Proceeding of 1st. Symposium of Nonimpact Printing Technology,
page 119-124, 1984), as shown by Fig. 10, in a record head having
an ink jet injection port 101 formed in a slit-like shape, an
upper plate 102 and a lower plate 103 for forming the ink
injection port 101, a record electrode 104 arranged on the lower
plate 103 by a unit of a record pixel, an opposed electrode
105 arranged opposedly to the ink injection port 101, a record
medium 110 moving along the opposed electrode 105 and a drive
power source 106 for supplying voltage to a selected electrode
of the record electrode 104, ink 108 is filled in the ink
injection port 101 and a voltage pulse 107 is applied between
the record electrode 104 and the opposed electrode 105 by which
the ink 108 is injected and flown ink 109 is adhered and permeated
onto the record medium 110 whereby desired output print or
picture is obtained.
According to the conventional slit jet system, by
replacing a nozzle used in ink jet recording by the ink injection
port 101 having a slender slit-like shape, the resolution can
be prevented from being restricted by the nozzle and further,
cleaning of the ink jet port 101 can be facilitated.
Further, according to the slit jet system, a plurality
of the ink injection ports 101 are used and the inks 108 having
different colors are injected into the respective ink injection
ports 101 by which color output printing can easily be provided.
The following problems are posed according to the
conventional ink jet recording system.
(1) It is difficult to promote the resolution since
nozzles are used for injecting ink.
(2) The ink jet recording system is classified into a
continuous type and an on-demand type. According to the
continuous type, although the record speed is high, the device
is difficult to simplify due to recovery of unnecessary ink
or the like whereas according to the on-demand type, although
the constitution of the device is simplified, the record speed
is difficult to accelerate.
The following problems are posed according to the slit
jet system for resolving the above-described problems of the
ink jet recording system.
(1) It is difficult to promote the resolution since ink
is flown by arranging record electrodes in correspondence with
the units of record pixels.
(2) It is difficult to optimize ink characteristic and
control applied voltage and timing thereof since in applying
voltage on the record electrodes, when a selected record
electrode and a nonselected record electrode are contiguous
to each other, discharge phenomenon is caused between the both
electrodes.
Hence, according to the present invention, it is a
problem thereof to provide a record unit in which highly fine
and high quality printing is carried out at high speed and output
printing in a noncontact state and where shape of a record medium
is not selected can be carried out, and a record device using
the record unit, a record unit and a record head used for the
record device.
In order to resolve the above-described problems,
according to the present invention, there is provided a record
head having a transparent electrode formed on a substrate, a
photoconductive film formed on the transparent electrode, means
for supplying ink on the photoconductive film, a slit plate
installed with a slit for controlling injection of the ink and
an opposed electrode in this order, the slit plate and the
opposed electrode being arranged with a gap therebetween
sufficient for incorporating a record medium, and at least
having a power source for applying a voltage between the
transparent electrode and the opposed electrode and light
irradiating means for supplying light in correspondence with
a desired pixel to the photoconductive film in a form of a pulse.
Further, as other constitution of the present invention,
according to the present invention, there is provided a record
head having a transparent electrode formed on a substrate, a
photoconductive film formed on the transparent electrode, means
for supplying ink on the photoconductive film, a slit plate
installed with a slit for controlling injection of the ink and
an opposed electrode in this order, the slit plate and the
opposed electrode being arranged with a gap therebetween
sufficient for incorporating a record medium, and at least
having a power source for applying a voltage between the
transparent electrode and the opposed electrode and light
irradiating means for irradiating light in correspondence with
a desired pixel to the photoconductive film, wherein an ink
storage groove for temporarily storing the ink is formed on
the substrate along a longitudinal direction of the slit and
the ink storage groove(s) are disposed in an ink chamber formed
between the substrate and the slit plate and disposed at an
upper side or a lower side or both sides of the slit in a direction
of a plane of the substrate.
Embodiments of the present invention will now be described by way of example
only and with reference to the accompanying drawings, in which:-
Fig. 1 is an explanatory view showing the constitution
of a record head according to a first example of the present
invention.
Fig. 2 is an explanatory view showing the constitution
of a record head according to a second example of the present
invention.
Fig. 3 is an explanatory view showing the constitution
of a record head according to a third example of the present
invention.
Fig. 4 is an explanatory view showing the constitution
of a record head according to a fourth example of the present
invention.
Fig. 5 is a disassembled perspective view showing the
constitution of a head unit of the record head according to
the fourth example of the present invention.
Fig. 6 is a disassembled perspective view showing the
constitution of the record head according to the fourth example
of the present invention and its peripheral mechanism.
Fig. 7 is an explanatory view showing the constitution
of a record head according to a fifth example of the present
invention.
Fig. 8 is a block diagram showing the constitution of
a recording device using the record head of the present
invention.
Fig. 9 is an explanatory view showing a first embodiment
of a record head of the present invention.
Fig. 10 is an explanatory view showing a record head
of a conventional slit jet system.
Fig. 9 shows a first embodiment of a record head
according to the present invention.
An explanation will be given of the constitution and
operation of a record head according to a first embodiment in
reference to Fig. 9 as follows.
First, an explanation will be given of the constitution
of the record head.
A head unit 54 of the record head is constituted by a
transparent substrate 58, a transparent electrode 2 formed on
the transparent substrate 58 and a photoconductive film 4 formed
on the transparent electrode 2, further, a slit plate 8 is
installed on the photoconductive film 4 via a spacer 55 for
forming an ink chamber 56 and a slit 57 for controlling injection
of the ink 6 is formed at the slit plate 8. Further, ink
supplying means 50 for supplying the ink 6 to the ink chamber
56 on the photoconductive film 4 is constituted at the head
unit 54.
Further, an opposed electrode 1 is installed around the
head unit 54 on the side of the slit plate 8 and the opposed
electrode 1 is arranged such that a gap sufficient for
incorporating a record medium 10 is formed between the opposed
electrode 1 and the slit plate 8. Paper feeding means (not
illustrated) for supplying the record medium 10 without being
brought into contact with the slit plate 8, a power source 3
for applying voltage between the transparent electrode 2 and
the opposed electrode 1 and light irradiating means 5 for
supplying light in correspondence with a desired picture pixel
to the photoconductive film 4 in a form of a pulse is installed
on the rear face side of the transparent substrate 58.
Next, an explanation will be given of the operation.
Light is irradiated to the photoconductive film 4 by using the
light irradiating means 5 from the rear face side of the
transparent substrate 58 in a state where high voltage is
applied between the transparent electrode 2 and the opposed
electrode 1 by the power source 3. By this operation, the
resistance value of an irradiated region of the photoconductive
film 4 is lowered and photocurrent is flown at the irradiated
region. Thereafter, electric charge is charged in the ink on
the photoconductive film 4 at the irradiated region of the
photoconductive film 4 and the ink is converted into flown ink
12 and is injected toward the side of the opposed electrode
1 by receiving Coulomb's force while an amount and
directionality of the ink are controlled by the slit plate 8.
The flown ink 12 is moved, permeated and adhered to the record
medium 10 on the opposed electrode 1 by Coulomb's force whereby
the desired picture pixel is provided on the record medium 10.
The record head described in the first embodiment of
the present invention sufficiently resolves the above-described
problems. That is, it is easy to promote the
resolution since it has no record electrode. Further, the
record head has a feature in which there causes no discharge
phenomenon between record electrodes since it has no record
electrode and it is easy to optimize the ink characteristic
and control applied voltage and timing thereof.
Further, attention has been paid to the following points
in order to improve the record head described in the first
embodiment.
That is, since high voltage is applied between the
transparent electrode on the head side and the opposed electrode,
in the recording operation, when a sufficient amount of ink
is not supplied to the slit portion after flying ink having
high insulating performance, the resistance value between the
electrodes may be lowered and the discharge phenomenon may occur.
Accordingly, the frequency of driving the record head described
in the first embodiment is significantly dependent on the
refilling rate of ink and the record speed is restricted
thereby.
Therefore, in order to improve the record head of the
first embodiment, the capacity of ink in the ink chamber must
be enlarged and a mechanism capable of supplying ink
sufficiently and at high speed is needed at the slit portion.
Although it is appropriate to expand the ink chamber formed
between the substrate and the slit plate in order to enlarge
the ink capacity, when the expansion of the ink capacity is
achieved by increasing, for example, the height of the ink
chamber, that is, a distance of the gap between the
photoconductive film face on the substrate and the slit plate,
since the amount of ink injected from the slit depends
significantly on the height of the ink chamber, the injected
ink amount is simultaneously increased and further, the amount
of consumption of ink is increased and accordingly, as a result,
the refilling rate of ink is not accelerated considerably.
Further, the resolution is obliged to lower by an increase in
the amount of injecting ink and since the amount of injecting
ink is increased, energy necessary for injection, that is, a
value of voltage applied between the both electrodes must be
increased or time of injection needs to be prolonged.
Further, when the expansion of the ink capacity is
achieved by expanding the ink chamber in the width direction
of the ink chamber, that is, a horizontal direction in respect
of the substrate face, since the amount of ink at the slit portion
is not increased, the amount of injecting ink remains unchanged
at the pertinent value and the refilling of ink is carried out
at high speed, however, the record head per se must be enlarged
in the direction of the substrate plane by an amount expanding
the ink chamber in the direction of the substrate plate. The
drawback is revealed significantly in arranging record heads
and performing color printing whereby the device is magnified.
Further, since the ink chamber is formed thinly with a wide
area in the head, when the head is not used in a long period
of time, the ink filled in the ink chamber is liable to evaporate
by which a solidified component of ink such as a pigment or
the like adheres to the slit portion and the slit portion is
clogged, further, the direction of injecting ink is varied
thereby, which may cause dimmed portions or nonuniformity of
dots and print quality may be deteriorated.
Further, when the record head is constituted by a line
head, the amount of consumption of ink per unit time period
is increased since the slit width as a injecting portion is
significantly wider than a serial head. Therefore, these
problems are revealed significantly in the case of a line head.
Further, the ink is flown by using electrostatic force
by applying high voltage between the electrodes and therefore,
when impurities or the like having high conductivity are mixed
in the ink, the discharge phenomenon may be caused.
According to the record head of the second embodiment
of the present invention, higher quality and higher speed of
print output are achieved by supplying ink stably and at high
speed, discharge phenomenon between the electrodes caused by
high voltage is prevented, ink is hardly clogged at the slit
portion and small-size formation can be achieved.
An explanation will be given of the record head according
to the second embodiment as follows.
According to a first constitution of the second
embodiment of the record head of the present invention, there
is provided a record head having a transparent electrode formed
on a substrate, a photoconductive film formed on the transparent
electrode, means for supplying ink on the photoconductive film,
a slit plate installed with a slit for controlling injection
of the ink and an opposed electrode in this order, the slit
plate and the opposed electrode being arranged with a gap
therebetween sufficient for incorporating a record medium, and
at least having a power source for applying a voltage between
the transparent electrode and the opposed electrode and light
irradiating means for supplying light in correspondence with
a desired pixel to the photoconductive film in a form of a pulse
wherein an ink storage groove for temporarily storing the ink
is formed on the substrate along a longitudinal direction of
the slit and the ink storage groove(s) are disposed in an ink
chamber formed between the substrate and the slit plate and
disposed at an upper side or a lower side or both sides of the
slit in a direction of a plane of the substrate.
The record head having the above-described first
constitution operates as follows.
When light is irradiated to the photoconductive film
by using the light irradiating means from the side of the
transparent electrode in a state where high voltage is applied
between the transparent electrode and the opposed electrode
by the power source, the resistance value of the photoconductive
film at the irradiated region is lowered and photocurrent is
flown at the irradiated region. Thereafter, a state where
electricity is conducted between the ink and the transparent
electrode is produced at the irradiated region of the
photoconductive film, electric charge is charged to the ink
on the photoconductive film, and the ink is flown toward the
side of the opposed electrode by receiving Coulomb's force and
adhered to the side of the record medium while the amount and
the directionality of the ink are controlled by the slit plate.
Thereby, desired picture pixels are provided on the record
medium. Further, when the ink is flown, the ink to be refilled
is supplied swiftly from the ink storage groove to the inside
of the ink chamber, that is, the slit portion.
Further, according to a second constitution of the
record head of the present invention, in the first constitution
of the record head, the record head of this constitution is
provided with a member having ink permeable fine pores in the
ink storage groove.
The record head of the above-described second
constitution operates as follows.
When light is irradiated to the photoconductive film
by using the light irradiating means from the side of the
transparent electrode in the state where high voltage is applied
by the power source between the transparent electrode and the
opposed electrode, the resistance value of the photoconductive
film at the irradiated region is lowered and photocurrent is
flown at the irradiated region. Thereafter, the state where
electricity is conducted between the ink and the transparent
electrode is produced at the irradiated region of the
photoconductive film, electric charge is charged at the ink
on the photoconductive film and the ink is flown toward the
side of the opposed electrode by receiving Coulomb's force and
adhered to the side of the record medium. Thereby, desired
picture pixels are provided on the record medium. Further, when
the ink is flown, at the inside of the record head, the ink
to be refilled is supplied at high speed to the inside of the
ink chamber, that is, the slit portion by a constant amount
after passing through the material having fine pores provided
in the ink storage groove.
Furthermore, according to a third constitution of the
record head of the present invention, in the record head of
the first constitution or the record head of the second
constitution, the record head of this constitution is provided
with ink accelerating means for accelerating further flown ink.
The record head of the above-described third
constitution operates as follows.
When light is irradiated to the photoconductive film
by using the light irradiating means from the side of the
transparent electrode in the state where high voltage is applied
by the power source between the transparent electrode and the
opposed electrode, the resistance value of the photoconductive
film at the irradiated region is lowered and photocurrent is
flown at the irradiated region. Thereafter, the state where
electricity is conducted between the ink and the transparent
electrode is produced at the irradiated region of the
photoconductive film, electric charge is charged to inside of
the ink on the photoconductive film, the ink is flown to the
side of the opposed electrode by receiving Coulomb's force and
thereafter, the flown ink is further accelerated by the
accelerating means and adhered to the side of the record medium.
Thereby, desired picture pixels are provided on the record
medium. Further, when the ink is flown, the ink to be refilled
is supplied swiftly from the ink storage groove to the inside
of the ink chamber, that is, the slit portion.
Furthermore, according to a fourth constitution of a
record head of the present invention, the record head described
in the first, or the second, or the third constitution, is
constituted in a line shape in correspondence with the print
width of the record medium.
The record head of the above-described fourth
constitution operates as follows.
When light is irradiated in a line shape to the
photoconductive film by the light irradiating means from the
side of the transparent electrode of the record unit in the
state where high voltage is applied by the power source between
the individual transparent electrodes and the opposed
electrodes, the resistance value of the photoconductive film
at the irradiated region is lowered and photocurrent is flown
at the irradiated region. Thereafter, the state where
electricity is conducted between the ink and the transparent
electrode is produced at the irradiated region of the
photoconductive film, electric charge is charged to inside of
the ink on the photoconductive film, the ink is flown toward
the side of the opposed electrode by receiving Coulomb's force,
the flown ink is moved, permeated and adhered to the record
medium on the opposed electrode and therefore, one line region
of desired picture pixels are provided on the record medium.
When the ink is flown, the ink to be refilled is supplied swiftly
from the ink storage groove to the inside of the ink chamber,
that is, the slit portion.
Furthermore, as a fifth constitution of the record unit
of the present invention, a plurality of the record heads having
one of the first through the fourth constitutions are used and
means for supplying inks having different colors to the
respective record heads are provided.
The record unit having the above-described sixth
constitution operates as follows.
When light is irradiated to the photoconductive film
by the light irradiating means from the side of the transparent
electrode of the record unit in the state where high voltage
is applied by the power source between the individual
transparent electrodes and the opposed electrode, the
resistance value of the photoconductive film at the irradiated
region is lowered and photocurrent is flown at the irradiated
region. Thereafter, a state where electricity is conducted
between the ink and the transparent electrodes is produced at
the irradiated region of the photoconductive film, electric
charge is charged to inside of the ink on the photoconductive
film, the ink is flown toward the side of the opposed electrode
by receiving Coulomb's force, the flown ink is moved, permeated
and adhered to the record medium on the opposed electrode and
accordingly, one dot, one line or one screen region of desired
picture elements are provided at the record medium. When the
ink is flown, the ink to be refilled is supplied swiftly from
the ink storage groove to the inside of the ink chamber, that
is, the slit portion. Further, by repeating the above-described
procedure at the record heads of the respective colors,
desired color print or color picture is provided on the record
medium.
An explanation will be given of examples of record heads
according to the second embodiment of the present invention
in reference to the drawings as follows.
Fig. 1 is an explanatory view showing the first
constitution of a record head according to the present
invention.
An explanation will be given of the total constitution
of the record head in reference to Fig. 1.
In Fig. 1, the record head is constituted by the head
unit 54, the ink supplying means 50 for supplying a necessary
amount of ink to the head unit 54, the light irradiating means
5 arranged on the right side (hereinafter, rear face side) of
the head unit 54 for irradiating light to the head unit 54,
the opposed electrode 1 arranged on the left side (hereinafter,
opposed face side) of the head unit 54 and the power source
3 for applying voltage between the opposed electrode 1 and an
electrode in the head unit 54.
An explanation will be given of the constitution of the
head unit 54.
As the material of the photoconductive film 4, an
inorganic conductor of a photoconductive single crystal
material of Se group, CdS group, ZnO group, BSO (Bi12SiO20)
or the like, hydrogenerated amorphous silicon of i type, pi
type, pin type or the like, or a lamination type organic
photoconductor such as CTL/CGL or the like can be used. As the
photoconductive film 4, the photoconductivity is important and
it is preferable that potential difference of surface potential
caused by attenuation of light is large. The dark resistance
of the inorganic photoconductor or the organic photoconductor
falls in a range of 1013 through 1014 Ω.cm and the resistance
value is lowered to 1010 through 1011 Ω.cm by irradiating light
to the photoconductive film 4 by which photocurrent is flown
in the irradiated region. Further, in respect of the film
thickness of the photoconductive film 4, 10 through 20 µm is
preferable and as electric properties, it is requested that
the resistance value at the dark place is large and high
sensitivity and fast light response are required which can be
satisfied by the above-described photoconductor.
Further, when amorphous silicon is used as the
photoconductive film 4, the dark resistance falls in a range
of 109 through 1011 Ω.cm and the resistance value can be lowered
to 104 through 106 Ω.cm by irradiating light to the
photoconductive film 4 by which large surface potential
difference can be ensured. Further, naturally, the larger the
film thickness of the photoconductive film, the more increased
is the dark resistance value, however, the resolution is
deteriorated at the film thickness of 20 through 100 µm or higher
and therefore, the optimum film thickness is 20 µm or lower,
preferably, about 10 µm.
Further, in order to increase the dark resistance value
as well as realize jumping of ink having high resolution by
minimizing expansion of electric charge in the direction of
film face, it is preferable to use hydrogenerated amorphous
silicon of i type where impurity elements are removed.
As the transparent electrode 2, ITO (Indium-Tin-Oxide)
or, a conductive high molecular material, a metal thin film
having a thinness sufficient for passing light (for example,
Al thin film having a film thickness of 0.03 µm or the like),
or ZnO, or SnO2 or compounds of these can be used. Further,
as the opposed electrode 1 of the present invention, a material
having excellent conductivity such as aluminum, copper, gold
or the like can be used.
Next, an explanation will be given of the constitution
of the ink supplying means 50.
Next, an explanation will be given of the constitution
of the light irradiating means.
As the light irradiating means 5 according to the present
invention, a semiconductor laser can be used and laser beam
is irradiated by the light irradiating means 5 in an arrow mark
7 direction from the rear face side of the transparent substrate
58 to a position on the photoconductive film 4 in correspondence
with a desired picture pixel. Further, the irradiated light
reaches the photoconductive film 4 after transmitting through
the transparent substrate 58 and the transparent electrode 2.
Thereby, the resistance value is lowered only at the irradiated
desired picture pixel region on the photoconductive film 4.
In this case, the photosensitivity can be promoted by promoting
the light attenuation rate of the photoconductive film 4 by
matching the oscillation wavelength of the laser beam with the
absorption coefficient of the photoconductive film 4 in respect
of the oscillation wavelength. Further, in respect of the laser
beam 7, the intensity of irradiated light, the shape of focus
light spot and the like of laser beam irradiated from a laser
oscillation device of a semiconductor laser or the like, are
optimized by an optical lens or the like and the laser beam
can be constituted by a laser beam scanning mechanism composed
of a polygonal mirror and the like at the light irradiating
means 5. According to the record head of the present invention,
laser beam is irradiated from the light irradiating means 5
and therefore, picture can be formed on the photoconductive
film 4 at a position in correspondence with a desired picture
pixel in a noncontact state and at high speed. Although
according to the example, a semiconductor laser is used as a
light emitting source of the light irradiating means 5, the
present invention is not limited thereto but He-Ne laser, a
semiconductor laser array, an LED array, a halogen lamp or the
like can be used sufficiently as the light emitting source.
Further, naturally, a light shutter array or a liquid crystal
television set may be used in place of the above-described laser
scanning optical system. Further, slit light exposure may be
performed by an analog optical system such as a copier and light
may be irradiated directly to the head unit 54 via an optical
system.
Next, an explanation will be given of the opposed
electrode 1 and the power source 3.
The opposed electrode 1 comprises a conductive material
and is arranged on the side of opposing the head unit 54 via
a clearance of about 0.2 through 1 mm from the slit plate face
of the head unit 54. In this case, the side of the opposed
electrode 1 is connected to the positive pole of the power source
3 and the side of the transparent electrode 2 in the head unit
54 is connected to the negative side thereof, respectively,
in printing, constant voltage is applied between the both
electrodes by the power source 3 and electric field is generated
at the clearance between the both electrodes. Although in Fig.
1, the shape of the opposed electrode 1 is constituted by a
plane, it is preferable to concentrate the electric field by
sharpening the opposed electrode face, constituting a shape
having a radius of curvature or the like and in this way, energy
necessary for injection of ink, that is, applied voltage or
applied pulse can be reduced.
Next, an explanation will be given of the operation.
First, constant high voltage is continuously applied
between the transparent electrode 2 and the opposed electrode
1 by the power source 3 by which a state where electric field
is generated between both is produced. Further, light is
irradiated by the light irradiating means 5 from the rear face
side of the transparent substrate 58 toward the position of
the slit 57 in correspondence with a desired picture recording
portion. Then, light transmits through the transparent
substrate 58 and the transparent electrode 2 and is irradiated
to the photoconductive film 4.
At this moment, the photoconductive phenomenon is
caused and photocurrent is flown at the light irradiated portion
inside of the photoconductive film 4. That is, carriers are
formed at the irradiated region of the photoconductive film
4 and transferred by the external electric field, as a result,
the impedance is lowered and the photocurrent is flown.
According to the embodiment, the negative pole is connected
to the side of the transparent electrode 2 and accordingly,
electrons emerge on the ink side at the light irradiated portion,
however, this is because the charge characteristic of the ink
according to the embodiment-is defined as negative and the
charge characteristic is not particularly limited thereto,
although it is necessary to correspond to the charge
characteristic of the ink.
Therefore, at the irradiated region of the
photoconductive film 4, the ink 6 and the transparent electrode
2 are brought into a conductive state and negative charge is
charged to inside of the ink 6 having high insulating
performance on the photoconductive film 4. Further, the ink
is attracted to the record medium 10 on the opposed electrode
1 by receiving Coulomb's force caused by the electric field
developed between the transparent electrode 2 and the opposed
electrode 1 and the flown ink 12 is injected from the slit 57
to the side of the opposed electrode 1 and is adhered to the
record medium.
Further, after flying the ink, a pertinent amount of
ink is filled from the ink storage groove 53 installed at the
vicinity of the slit 57 to the flown ink portion sufficiently
faster than a successive timing of injecting ink.
Fig. 2 is an explanatory view showing the second
constitution of a record head according to the present
invention.
An explanation will be given of the total constitution
of the record head in reference to Fig. 2.
In Fig. 2, the record head is constituted by the head
unit 54, the ink supplying means 50 for supplying a necessary
amount of ink to the head unit 54, the light irradiating means
5 arranged on the rear face side of the head unit 54 for
irradiating light to the head unit 54, the opposed electrode
1 arranged on the opposed face side of the head unit 54 and
the power source 3 for applying voltage between the opposed
electrode 1 and the electrode in the head unit 54.
An explanation will be given of the constitution of the
head unit 54.
Next, an explanation will be given of the constitution
of the ink supplying means 50.
Next, an explanation will be given of the constitution
of the light irradiating means.
As the light irradiating means 5 according to the present
invention, similar to Example 1, a semiconductor laser can be
used and laser beam from the light irradiating means 5 is
irradiated in the arrow mark 7 direction from the rear face
side of the transparent substrate 58 to the position on the
photoconductive film 4 in correspondence with a desired picture
pixel. Further, the irradiated light reaches the
photoconductive film 4 by transmitting through the transparent
substrate 58 and the transparent electrode 2. Thereby, a
resistance value of only the irradiated desired picture pixel
region is lowered on the photoconductive film 4.
Next, an explanation will be given of the constitutions
of the opposed electrode 1 and the power source 3.
The opposed electrode 1 comprises a conductive material
and is arranged on the opposed face side of the head unit 54
via a clearance of about 0.2 through 1 mm from the slit plate
face of the head unit 54. In this case, the side of the opposed
electrode 1 is connected to the positive pole of the power source
3 and the side of the transparent electrode 2 in the head unit
54 is connected to the negative pole thereof, respectively,
constant voltage is applied between the both electrodes by the
power source 3 in printing and electric field is generated at.
the clearance between the both electrodes.
Next, an explanation will be given of the operation.
First, constant high voltage is continuously applied
between the transparent electrode 2 and the opposed electrode
1-by the power source 3 by which a state where electric field
is generated between both is produced. Further, light is
irradiated by the light irradiating means 5 from the rear face
side of the transparent substrate 58 toward the position of
the slit 57 in correspondence with a desired picture recording
portion. Then, light transmits through the transparent
substrate 58 and the transparent electrode 2 and is irradiated
to the photoconductive film 4.
At this moment, the photoconductive phenomenon is
caused and photocurrent is flown at the light irradiated portion
inside of the photoconductive film 4. That is, carriers are
formed at the irradiated region of the photoconductive film
4 and transferred by the external electric field, as a result,
the impedance is lowered and the photocurrent is flown.
Therefore, in the irradiated region of the
photoconductive film 4, the ink 6 and the transparent electrode
2 are brought into a conductive state, and negative charge is
charged locally in the ink 6 having high insulating performance
on the photoconductive film 4. Further, the ink is attracted
to the record medium 10 on the opposed electrode 1 by receiving
Coulomb's force by electric field developed between the
transparent electrode 2 and the opposed electrode 1 and the
flown ink 12 is injected to the side of the opposed electrode
1 from the slit 57 and adhered to the record medium.
Further, after flying ink, a pertinent amount of ink
is filled to the flown ink portion by the ink storage groove
53 installed at the vicinity of the slit 57 sufficiently faster
than a successive timing of ink injection, further, impurities
are removed by passing the ink 6 through the porous material
65 and the ink with a constant pressure and a pertinent amount
is filled in the slit by receiving uniform flow resistance.
Thereby, the ink is supplied always stably to the slit and the.
stable recording operation can be performed by firmly
restraining the discharge phenomenon which may be caused
between the opposed electrode and the transparent electrode
under application of voltage by removing impurities in the ink.
Fig. 3 is an explanatory view showing the third
constitution of a record head according to the present
invention.
An explanation will be given of the total constitution
of the record head in reference to Fig. 3.
In Fig. 3, the record head is constituted by the head
unit 54, the ink supplying means 50 for supplying a necessary
amount of ink to the head unit 54, the light irradiating means
5 arranged on the rear face side of the head unit 54 for
irradiating light to the head unit 54, the opposed electrode
1 arranged on the opposed face side of the head unit 54, the
power source 3 for applying voltage between the opposed
electrode 1 and the electrode in the head unit 54 and
accelerating means for accelerating the injected ink in the
flying direction.
An explanation will be given of the constitution of the
head unit 54.
Next, an explanation will be given of the constitution
of the ink supplying means 50.
Next, an explanation will be given of the constitution
of the light irradiating means.
As the light irradiating means 5 according to the present
invention, similar to Example 1, a semiconductor laser can be
used and laser beam from the light irradiating means 5 is
irradiated in the arrow mark 7 direction from the rear face
side of the transparent substrate 58 to the position on the
photoconductive film 4 in correspondence with a desired picture
pixel. Further, the irradiated light reaches the
photoconductive film 4 after transmitting through the
transparent substrate 58 and the transparent electrode 2.
Thereby, the resistance value of only the irradiated desired
picture pixel region is lowered on the photoconductive film
4.
Next, an explanation will be given of the constitutions
of the opposed electrode 1 and the power source 3.
The opposed electrode 1 comprises a conductive material
and is arranged on the opposed face side of the head unit 54
via a clearance of about 0.2 through 1 mm from the slit plate
face of the head unit 54. In this case, the side of the opposed
electrode 1 is connected to the positive pole of the power source
3 and the side of the transparent electrode 2 in the head unit
54 is connected to the negative pole thereof, respectively,
constant voltage is applied between the both electrodes by the
power source 3 in printing and electric field is generated at
the clearance between the both electrodes.
Next, an explanation will be give of the constitution
of an accelerating means 14.
The accelerating means 14 is arranged between the slit
plate 8 and the opposed electrode 1. The accelerating means
14 is fabricated by a material having excellent conductivity
of aluminum, copper, gold or the like and may be of a condenser
fabricated by a set of flat plates, or a member having a shape
of a closed tube such as a cylinder or the like may be used.
The speed of the flown ink 12 is accelerated by the
accelerating means 14 of the example and further, the amount
of energy supplied to the photoconductive film 4 can be reduced
by controlling a voltage value applied for flying the ink 6
and the light energy provided from the light irradiating means
5. Further, according to the accelerating means 14, voltage
is applied to the accelerating means 14 from the electrode of
the power source 3 on the side of the opposed electrode 1 via
a resistor in this example. However, application of potential
to the accelerating means 14 is not limited thereto but, for
example, the potential difference between the transparent
electrode 2 and the accelerating means 14 can be made larger
than the potential difference between the transparent electrode
2 and the opposed electrode 1. This is determined by the amount
of the flown ink 12, a distance between the accelerating means
14 and the surface of the ink 6 or the like.
Further, as shown by Fig. 3, by using a switch function
in the opposed electrode 1, the ink 6 can be flown only by the
accelerating means 14.
Next, an explanation will be given of the operation as
follows.
First, constant high voltage is continuously applied
between the transparent electrode 2 and the opposed electrode
1 by the power source 3 by which a state where electric field
is generated between both is produced. Further, light is
irradiated by the light irradiating means 5 from the rear face
side of the transparent substrate 58 toward the position of
the slit 57 in correspondence with a desired picture recording
portion. Then, light transmits through the transparent
substrate 58 and the transparent electrode 2 and is irradiated
to the photoconductive film 4.
At this moment, the photoconductive phenomenon is
caused and photocurrent is flown at the light irradiated portion
inside of the photoconductive film 4. That is, carriers are
formed at the irradiated region of the photoconductive film
4 and transferred by the external electric field, as a result,
the impedance is lowered and the photocurrent is flown.
Therefore, a state where the ink 6 and the transparent
electrode 2 are brought into a conductive state is produced
at the irradiated region of the photoconductive film 4 and
negative charge is charged locally at inside of the ink 6 having
high insulating performance on the photoconductive film 4. And
the ink is attracted to the record medium 10 on the opposed
electrode 1 by receiving Coulomb's force by electric field
developed between the transparent electrode 2 and the opposed
electrode 1, the flown ink 12 is injected from the slit 57 to
the side of the opposed electrode 1, further, the flown ink
12 is accelerated by the accelerating means 14 and the flown
ink 12 is adhered to the record medium 10 by inserting the record
medium 10 between the opposed electrode 1 and the accelerating
means 14 from paper feeding means (not illustrated).
Further, after flying ink, a pertinent amount of ink
is filled to the flown ink portion by the ink storage groove
53 installed at the vicinity of the slit 57 sufficiently faster
than a successive timing of ink injection.
Fig. 4 is an explanatory view showing a record head of
a line shape that is the fourth constitution according to the
present invention. Further, Fig. 5 is a disassembled
perspective view of the head unit 54 of the record head and
Fig. 6 is a perspective view showing the constitution of the
record head and its periphery.
First, an explanation will be given of the constitution
of the record head in reference to Fig. 4 and Fig. 5.
An explanation will be given of the constitutions of
the head unit and the ink supplying means.
Further, the transparent electrode 2 and the
photoconductive film 4 are successively laminated on the face
of the transparent substrate 58 on the opposed face side by
using screen printing or the like.
Further, the slit plate 8 having a slit opening portion
of about the width of the record medium 10 is constituted on
the opposed face side of the transparent substrate 58 such that
a recessed portion where the ink storage groove 53 and the ink
chamber 56 are formed, is closed. Thereby, the ink storage
groove 53 and the ink chamber 56 are formed as a space
hermetically sealed at other than the opening portion of the
slit 57.
Further, in respect of the transparent electrode 2, the
photoconductive film 4 is not laminated at the right end portion
of the transparent substrate 58 in order to form a lead-out
portion of the electrode and the transparent electrode 2 is
in an exposed state and an electrode line of a flexible substrate
70 or the like is press-contacted, bonded by conductive bonding
or soldered to the portion thereby providing an electrode
contact. Further, a gap portion between the transparent
substrate 58 and the slit plate 8 produced when the slit plate
8 is attached, is filled with a sealing member 71 or an adhesive
agent by which the portion where the transparent electrode 2
is exposed is prevented from being brought into contact with
ink.
Further, ink supply holes 60 for flowing ink from the
ink supply path 51 into the record head penetrate the bottom
portion of the ink storage groove 53 of the transparent
substrate 58 to the rear face side. The ink supply holes 60
are provided at two locations on the both ends of the transparent
substrate 58 in the longitudinal direction and one of them
constitutes a hole for air vent such that bubbles are not stored
in the ink storage groove 53 and the ink chamber 56 when ink
is injected.
Further, a reinforcing plate 59 is disposed on the rear
face side of the transparent substrate 58 and the ink tank 52
is disposed on the rear face side of the reinforcing plate 59.
The ink supply paths 51 are provided in the reinforcing plate
59 at positions the same as those of the ink supply holes 60
provided to the transparent substrate 58 and are formed to
penetrate projected portions on the rear face side of the
reinforcing plate 59. Further, by inserting the projected
portions into the ink tank 52, ink in the ink tank 52 is flown
through the ink supply paths 51. Further, although an adhesive
agent or the like may be filled between the ink supply holes
60 and the ink supply paths 51 and between the ink supply paths
51 and the ink tank 52 such that ink is not leaked when the
head is formed, it is preferable to insert sealing members of
O rings, oil seals or the like between the respective
substrates.
Further, the reinforcing plate 59 is provided simply
for reinforcing the transparent substrate 58 and reducing warp
thereof and fixing the ink tank 52 provided on the side of the
reinforcing plate opposed to the substrate and is not
necessarily needed when the above-described points are
satisfied by the transparent substrate 58.
Next, an explanation will be given of the constitution
of the light irradiating means 5.
As shown by Fig. 6, a polygonal scanner 61 using a
semiconductor laser that is the light irradiating means, is
disposed on the rear face side of the head unit 54 and laser
beam condensed at the slit position of the head unit 54 via
a condensing optical system or the like, is irradiated while
being scanned in the slit direction.
Next, an explanation will be given of the constitutions
'of the opposed electrode 1 and the power source 3.
The opposed electrode 1 in a drum shape comprising a
conductive material is arranged on the opposed face side of
the head unit 54. The drum main body is disposed by maintaining
a constant distance from the face of the slit 57 of the head
unit 54 such that the drum main body is not brought into contact
with the face of the slit 57 and is pivotable in the clockwise
direction, that is, paper feeding direction by a drive system,
not illustrated. Further, according to the drum, electric
contact is provided by bringing an elastic thin plate electrode
in press-contact with the periphery of the drum or the axial
end (not illustrated) and the electrode is connected to the
power source 3.
Next, an explanation will be given of the constitution
of paper feeding means 11 around the record head.
The paper feeding means 11 is constituted by paper
supplying means 62 and paper transferring means 63 as shown
by Fig. 4.
The paper feeding means 62 is arranged on the upstream
side of the paper feeding means 11, the paper feeding means
62 is constituted by a drive roller and a rotatable pinch roller
and the pinch roller is brought into press-contact with the
drive roller in a rotatable state.
Paper guides 64 comprising an insulating material are
arranged around the periphery of the drum of the opposed
electrode 1 and guide the record medium 10 transferred by the
paper feeding means 62 such that the record medium 10 is
transferred along the shape of the drum.
Further, the drum of the opposed electrode 1 is pivoted
by a drive system, not illustrated, with a motor speed of which
can be controlled such as a pulse motor or a DC servo motor
or the like as a drive source via a gear wheel train and a pulley
belt drive system and an elastic pinch roller of rubber,
urethane or the like is brought into press-contact with the
lower end of the drum rotatably. Accordingly, a mechanism for
transferring the record medium 10 supplied from the paper
feeding means 62 by driving the drum of the opposed electrode
1, is constituted and the portion constitutes the paper
transferring means 63.
Next, an explanation will be given of the operation of
the record head and the paper feeding means 11 in reference
to Fig. 4 and Fig. 6.
First, the record medium 10 is supplied to the side of
the opposed electrode 1 by the paper feeding means 62, made
to pass through a very small clearance between the drum
peripheral face of the opposed electrode 1 and the paper guides
and transfer to the paper transferring means 63 along the drum
peripheral face of the opposed electrode 1. The front end of
the record medium 10 is inserted between the opposed electrode
1 and the pinch roller and heading of record position is carried
out by detecting position by using an edge sensor or the like
and the transfer of the record medium 10 is once stopped.
Thereafter, by continuously applying a constant voltage
value set by the power source 3 between the transparent
electrode 2 and the opposed electrode 1, a state where electric
field is generated between both, is produced. Further,
light is irradiated from the rear face side toward the slit
position of the head unit 54 by the polygonal scanner 61 that
is the light irradiating means in correspondence with a desired
is the light irradiating means in correspondence with a desired
picture pattern.
Light incident on the head unit 54 transmits through
the transparent substrate 58 and the transparent electrode 2
and is irradiated to the photoconductive film 4. At this
occasion, the photoconductive phenomenon is caused in the
photoconductive film 4 at the light irradiated portion,
photocurrent is flown, a state where the ink 6 and the
transparent electrode 2 are brought into a conductive state
is produced at the irradiated region and negative charge is
charged locally at inside of the ink 6 having high insulating
performance on the photoconductive film 4. Further, by
electric field developed between the transparent electrode 2
and the opposed electrode 1, the ink is flown and adhered to
the record medium 10 on the opposed electrode 1 by receiving
Coulomb's force.
After flying ink, a pertinent amount of ink is filled
to the flown portion of the ink chamber 56 by the ink storage
groove 53 provided at the vicinity of the slit 57 sufficiently
faster than a successive timing of ink injection.
When the operation is repeated in the main scanning
direction by the polygonal scanner 61 and 1 line of main scan
is finished, the record medium 10 is transferred to a second
line by driving the paper transferring means 63, that is, the
drum of the opposed electrode 1 in the sub scanning direction
by a dot pitch having necessary resolution.
By successively repeating the recording in the main
scanning direction and the transferring the record medium 10
in the sub scanning direction, two-dimensional recording is
carried out on the record medium 10.
Although as described above, according to examples 1
through 4, an explanation has been given of examples where the
ink storage groove is disposed on the upper side of the slit
in the direction of the face of the substrate, the ink storage
groove may naturally be disposed on the lower side of the slit
or both on the upper and the lower sides. The ink storage groove
may be formed such that the portion of the slit is avoided,
that is, at a position not blocking light from the light
irradiating means.
Fig. 7 is an explanatory view showing the sixth
constitution of a record head 71 according to the present
invention.
In Fig. 7, four of the record heads 71 each in a line
shape in correspondence with the width of print of the record
medium 10 as shown by Example 6, are laminated vertically and
inks 6 of yellow (Y), magenta (M), cyan (C) and black (Bk) are
supplied from the upper portions of the respective record heads
71 to the record heads 71. As procedure of recording, a state
where high voltage is applied between the individual
transparent electrodes 2 and the opposed electrode 1 is produced,
light is irradiated in an arrow mark 7 direction from the side
of the transparent electrode 2 of the yellow ink record head
71 to the photoconductive film 4 by the light irradiating means
5, the resistance value of the photoconductive film 4 at the
irradiated region is lowered and photocurrent is flown.
Thereafter, a state where the ink 6 and the transparent
electrode 2 are brought into a conductive state is produced
at the irradiated region of the photoconductive film 4, electric
charge is charged inside of the yellow ink on the
photoconductive film 4, the yellow ink is flown toward the side
of the opposed electrode 1 by receiving Coulomb's force, the
flown yellow ink is moved, permeated and adhered to the record
medium 10 on the opposed electrode 1 and accordingly, a desired
pixel of yellow ink is provided on the record medium 10 in 1
line region. Next, the yellow ink record unit is moved in an
arrow mark 17 direction and the desired pixel of magenta ink
is provided on the record medium 10 in 1 line region by the
magenta ink record head 71 through above-described recording
procedure. Next, the magenta ink record head 71 is moved in
the arrow mark 17 direction, a desired pixel of cyan ink is
provided on the record medium 10 in 1 line region by the cyan
ink record head 71 through the above-described recording
procedure. Next, the cyan ink record head 71 is moved in the
arrow mark 17 direction, the desired pixel of black ink is
provided on the record medium 10 in 1 line region by the black
ink record head 71 through the above-described recording
procedure. Thereafter, the record medium 10 is moved in a 1
line arrow mark 19 direction by paper feeding means, not
illustrated, the four record heads 71 are driven in an arrow
mark 18 direction back to the home positions, the above-described
procedure is repeated and the desired color pixels
for each picture is provided on the record medium 10.
Although according to the embodiment, the inks 6 are
constituted by 4 kinds, by increasing the number of the record
heads 71 and supplying individually the inks 6 of multiple
colors, highly fine output print or picture of full color with
no restriction in the color of print is provided.
Further, although according to the example, an
explanation has been given of a system where the record heads
71 of the present invention are driven at every time of
transcribing the respective colors of YMCBk onto the record
medium 10, by providing a structure of simultaneously making
access to the respective pixel information of YMCBk in the light
irradiating means 5, the record pixel information of the
respective colors of YMCBk can naturally be irradiated onto
the photoconductive film 4 simultaneously.
Although according to the example 5, an explanation has
been given of the structure of the record head 71 in a line
shape the present invention is not limited thereto but, for
example, a plurality of serial heads may be arranged and the
main scanning direction may be controlled respectively and
independently from each other.
An explanation will be given of the operation of the
record device when each of the record heads 71 comprising the
constitutions of Examples 1 through 5 is used in reference to
a block diagram shown by Fig. 8.
Fig. 8 is an explanatory view showing the constitution
of the record device using each of the record heads 71 described
in the first through the fifth examples of the present invention.
In Fig. 8, a record device 30 inputs picture data 29 from an
outside device 28, picture modifying processing or pattern
recognition is carried out at a picture processing circuit 25,
data transformation is carried out for each pixel and picture
pixel data 31 is outputted. The picture pixel data 31 is
transferred to inside of a record unit 24 in synchronism with
a trigger signal 36 from a controller 26 and a flown ink 32
in correspondence with the picture pixel data 31 is adhered
and transcribed from the record unit 24 to the record paper
10 that is the record medium. At this moment, synchronization
of the flown ink 32 and the record paper 10 is carried out by
outputting a control signal 33 from the controller 26 to paper
feeding means 11. Further, a voltage value 34 in the record
unit 24 is set to a power source unit 27 from the controller
26 and voltage 35 is supplied from the power source unit 27
to the record unit 24. Further, an output of a light control
signal 37 of a light source irradiation light intensity and
an irradiated pulse width in the record unit 24 or a drive
processing signal 38 of an optical part or the like is controlled
by the controller 26 whereby dots formed on the record paper
10 are controlled. By carrying out the above-described
procedure, the record unit 24 of the present invention, as the
record device 30, can perform highly fine 'printing with high
quality at high speed and can provide output print in a
noncontact state without selecting the shape of the record
medium.
As has been explained, according to the present
invention, in a record head having a transparent electrode
formed on a substrate, a photoconductive film formed on the
transparent electrode, means for supplying ink on the
photoconductive film, a slit plate provided with a slit for
'controlling injection of ink and an opposed electrode in this
order, the slit plate and the opposed electrode being arranged
with a sufficient gap therebetween for incorporating a record
medium and at least having a power source applying voltage
between the transparent electrode and the opposed electrode
and light irradiating means for irradiating light in
correspondence with a desired pixel to the photoconductive film,
an ink storage groove for temporarily storing ink on the
substrate is formed along the longitudinal direction of the
slit, the ink storage groove is disposed at inside of an ink
chamber formed between the substrate and the slit plate and
is disposed on the upper side, or the lower side, the both sides
of the slit in the direction of the face of the substrate and
accordingly, the following effects are achieved.
(1) A sufficient amount of ink can be supplied at high
speed to the slit portion after flying ink in printing and
accordingly, the drive frequency of the record head can be
accelerated. That is, the record speed as the device can be
accelerated. Further, thereby, the discharge phenomenon
between the opposed electrode and the slit which may occur by
deficiency in supplying ink can be avoided.
(2) The ink injecting portion of the record head is
provided with a slit shape and accordingly, different from a
record head having a conventional nozzle shape, ink is
communicated in one channel by the ink chamber and the ink
storage groove and accordingly, ink is brought into the state
of being difficult to dry. Further, the ink supply groove is
provided at the vicinity of the slit portion in the record head
and therefore, ink is filled always sufficiently in the slit
portion. Therefore, ink clogging of the slit portion caused
by evaporation or solidification of ink is difficult to occur
and stable high quality recording can be performed.
(3) Regardless of the amount of ink in the ink tank,
a constant amount of ink is stored always in the ink storage
groove and therefore, a necessary amount of ink can be supplied
stably to the slit portion by which stable recording can be
performed.
(4) The ink supply amount is increased by deepening the
groove in the depth direction according to the ink supply groove
in the record head and therefore, the ink chamber is not expanded
in the direction of the plane of the substrate, the head can
be constituted while saving space and particularly in forming
the device such that colors can be constituted by arranging
the record heads of the respective colors, the device can be
downsized.
Further, when a member having very fine pores whereby ink can be
communicated to the ink storage groove is provided in the record head, the following
effects are achieved in addition to the above-described effects.
(5) A proper supply amount of ink can be controlled by flow resistance which ink
receives in passing through the member.
(6) Impurities in ink at very fine pores can be removed by passing the ink through
the member by which the discharge phenomenon caused by clogging of ink at the slit or
the ink path or by mixing impurities can be prevented.
The aforegoing description has been given by way of example only and it will be
appreciated by a person skilled in the art that modifications can be made without
departing from the scope of the present invention.
Claims (6)
- A record head having a transparent electrode formed on a substrate, a photoconductive film formed on the transparent electrode, means for supplying ink on the photoconductive film, a slit plate having a slit or slot for controlling ejection of the ink and an opposed electrode, the slit plate and the opposed electrode being arranged with a gap therebetween sufficient for receiving a recording medium, and having a power source for applying a voltage between the transparent electrode and the opposed electrode and light irradiating means for irradiating light on to the photoconductive film in correspondence with a desired pixel:
wherein an ink storage groove for temporarily storing ink is formed on the substrate along a longitudinal direction of the slit, the ink storage groove being disposed in an ink chamber formed between the substrate and the slit plate and disposed at an upper side or a lower side or both sides of the slit in a direction of a plane of the substrate. - The record head according to claim 1, wherein a member having ink communicable fine pores is installed inside the ink storage groove.
- The record head according to claim 1 or 2, wherein accelerating means for accelerating the ink is provided between the slit plate and the opposed electrode.
- The record head according to any one of claims 1 to 3, wherein the record head is provided with a line shape in correspondence with a print width of the recording medium.
- A record head, wherein a plurality of the record heads according to any one of claims 1 to 4 are used, including means for supplying inks having different colours to the respective record heads and pixels having a plurality of colours formed by the inks having different colours are adhered to the recording medium.
- A record head having a transparent electrode formed on a substrate, a photoconductive film formed on the transparent electrode, means for supplying ink on the photoconductive film, a slit plate having a slit or slot for controlling ejection of the ink and an opposed electrode, the slit plate and the opposed electrode being arranged with a gap therebetween sufficient for receiving a recording medium, and having a power source for applying a voltage between the transparent electrode and the opposed electrode and light irradiating means for supplying light on to the photoconductive film in a form of a pulse and in correspondence with a desired pixel.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1438197A JPH10202882A (en) | 1997-01-28 | 1997-01-28 | Recording head |
JP14381/97 | 1997-01-28 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0855280A2 true EP0855280A2 (en) | 1998-07-29 |
EP0855280A3 EP0855280A3 (en) | 1999-03-10 |
Family
ID=11859479
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98300566A Withdrawn EP0855280A3 (en) | 1997-01-28 | 1998-01-27 | Record head |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0855280A3 (en) |
JP (1) | JPH10202882A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013193390A (en) * | 2012-03-22 | 2013-09-30 | Ricoh Co Ltd | Droplet discharge device |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3484162A (en) * | 1963-10-03 | 1969-12-16 | Xerox Corp | Electroviscous recording |
JPS5881171A (en) * | 1981-11-10 | 1983-05-16 | Ricoh Co Ltd | Ink jet recorder |
JPS58207058A (en) * | 1982-04-30 | 1983-12-02 | Yokogawa Hokushin Electric Corp | Recording device |
JPS62156674A (en) * | 1985-12-27 | 1987-07-11 | Seikosha Co Ltd | Electrophotographic recorder |
EP0268277A2 (en) * | 1986-11-19 | 1988-05-25 | Canon Kabushiki Kaisha | Ink jet recording head, ink jet recording device and method for working ink jet recording head |
JPH0272960A (en) * | 1988-09-07 | 1990-03-13 | Toshiba Corp | Electrostatic acceleration type ink-jet recorder |
JPH03288652A (en) * | 1990-04-04 | 1991-12-18 | Sharp Corp | Ink cartridge and ink supply device |
JPH05193135A (en) * | 1992-01-17 | 1993-08-03 | Olympus Optical Co Ltd | Recording device |
EP0670220A2 (en) * | 1994-03-04 | 1995-09-06 | Canon Kabushiki Kaisha | An ink jet recording apparatus |
WO1995025637A1 (en) * | 1994-03-21 | 1995-09-28 | Spectra, Inc. | Simplified ink jet head |
JPH0895356A (en) * | 1994-09-28 | 1996-04-12 | Nec Corp | Image forming device |
US5534898A (en) * | 1989-01-13 | 1996-07-09 | Canon Kabushiki Kaisha | Ink jet head, ink jet apparatus and wiping method therefor |
-
1997
- 1997-01-28 JP JP1438197A patent/JPH10202882A/en active Pending
-
1998
- 1998-01-27 EP EP98300566A patent/EP0855280A3/en not_active Withdrawn
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3484162A (en) * | 1963-10-03 | 1969-12-16 | Xerox Corp | Electroviscous recording |
JPS5881171A (en) * | 1981-11-10 | 1983-05-16 | Ricoh Co Ltd | Ink jet recorder |
JPS58207058A (en) * | 1982-04-30 | 1983-12-02 | Yokogawa Hokushin Electric Corp | Recording device |
JPS62156674A (en) * | 1985-12-27 | 1987-07-11 | Seikosha Co Ltd | Electrophotographic recorder |
EP0268277A2 (en) * | 1986-11-19 | 1988-05-25 | Canon Kabushiki Kaisha | Ink jet recording head, ink jet recording device and method for working ink jet recording head |
JPH0272960A (en) * | 1988-09-07 | 1990-03-13 | Toshiba Corp | Electrostatic acceleration type ink-jet recorder |
US5534898A (en) * | 1989-01-13 | 1996-07-09 | Canon Kabushiki Kaisha | Ink jet head, ink jet apparatus and wiping method therefor |
JPH03288652A (en) * | 1990-04-04 | 1991-12-18 | Sharp Corp | Ink cartridge and ink supply device |
JPH05193135A (en) * | 1992-01-17 | 1993-08-03 | Olympus Optical Co Ltd | Recording device |
EP0670220A2 (en) * | 1994-03-04 | 1995-09-06 | Canon Kabushiki Kaisha | An ink jet recording apparatus |
WO1995025637A1 (en) * | 1994-03-21 | 1995-09-28 | Spectra, Inc. | Simplified ink jet head |
JPH0895356A (en) * | 1994-09-28 | 1996-04-12 | Nec Corp | Image forming device |
Non-Patent Citations (7)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 11, no. 391 (P-649), 22 December 1987 & JP 62 156674 A (SEIKOSHA CO LTD), 11 July 1987 * |
PATENT ABSTRACTS OF JAPAN vol. 14, no. 256 (M-980), 4 June 1990 & JP 02 072960 A (TOSHIBA CORP), 13 March 1990 * |
PATENT ABSTRACTS OF JAPAN vol. 16, no. 122 (M-1226), 27 March 1992 & JP 03 288652 A (SHARP CORP), 18 December 1991 * |
PATENT ABSTRACTS OF JAPAN vol. 17, no. 623 (M-1511), 17 November 1993 & JP 05 193135 A (OLYMPUS OPTICAL CO LTD), 3 August 1993 * |
PATENT ABSTRACTS OF JAPAN vol. 7, no. 177 (M-233), 5 August 1983 & JP 58 081171 A (RICOH KK), 16 May 1983 * |
PATENT ABSTRACTS OF JAPAN vol. 8, no. 58 (P-261), 16 March 1984 & JP 58 207058 A (YOKOGAWA DENKI SEISAKUSHO KK), 2 December 1983 * |
PATENT ABSTRACTS OF JAPAN vol. 96, no. 8, 30 August 1996 & JP 08 095356 A (NEC CORP), 12 April 1996 * |
Also Published As
Publication number | Publication date |
---|---|
EP0855280A3 (en) | 1999-03-10 |
JPH10202882A (en) | 1998-08-04 |
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