An image forming apparatus, with an image forming device for forming an image on a sheet, and a position restricting unit being in contact with a surface of the sheet on a side of said image forming apparatus and keeping distance between the sheet and said image forming device constant....http://www.google.de/patents/US5980132?utm_source=gb-gplus-sharePatent US5980132 - Image forming apparatus with means for maintaining constant distance between recording head and recording sheet
