Image processing apparatus, printing apparatus and storage medium

(12) United States Patent

Shibata et al.

US006530638B2

(io) Patent No.: US 6,530,638 B2 (45) Date of Patent: Mar. 11,2003

(54) IMAGE PROCESSING APPARATUS,

PRINTING APPARATUS AND STORAGE
MEDIUM

(75) Inventors: Tsuyoshi Shibata, Kanagawa (JP);

Noribumi Koitabashi, Kanagawa (JP);
Masataka Yashima, Tokyo (JP);
Hitoshi Tsuboi, Tokyo (JP)

(73) Assignee: Canon Kabushiki Kaisha, Tokyo (JP)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.

(21) Appl. No.: 09/987,505

(22) Filed: Nov. 15, 2001

(65) Prior Publication Data

US 2002/0097294 Al Jul. 25, 2002 (30) Foreign Application Priority Data

Nov. 17, 2000 (JP) 2000/352002

(51) Int. C I. B41J 2/205

(52) U.S. CI 347/15; 347/43; 358/3.1

(58) Field of Search 347/15, 43, 100;

358/1.9, 3.01, 3.1, 501, 502

(56) References Cited

U.S. PATENT DOCUMENTS

4,313,124 A 1/1982 Hara 347/57

4,345,262 A 8/1982 Shirato et al 347/10

4,459,600 A 7/1984 Sato et al.

4,463,359 A 7/1984 Ayata et al 347/56

4,558,333 A 12/1985 Sugitani et al 347/65

4,723,129 A 2/1988 Endo et al 347/56

4,740,796 A 4/1988 Endo et al 347/56

5,852,454 A * 12/1998 Kanematsu et al 347/43

FOREIGN PATENT DOCUMENTS

JP 59123670 7/1984

JP 59138461 8/1984

* cited by examiner

Primary Examiner—Lamson Nguyen

(74) Attorney, Agent, or Firm—Fitzpatrick, Cella, Harper &

Scinto

(57) ABSTRACT

In an image printed by a printing apparatus, graininess particularly in a light part of the printed image is reduced by relatively simple structure by using a second color. To do so, magenta and cyan color component data in image data is subjected to under color removal to generate image data of a blue ink being the secondary color. On the basis of the data of the blue ink replaced for magenta and cyan, printing is performed by forming dots of the blue ink. At this time, black data is distributed into dark black and light black by density distribution, and the light black is substituted by the blue and yellow inks, whereby it is possible by the simple structure to prevent the graininess appeared when the cyan and magenta dots mutually appear biasedly and the graininess due to the black ink dots.

25 Claims, 11 Drawing Sheets