JPS57109961A - Two-color copying method and its apparatus - Google Patents

Abstract

PURPOSE:To easily obtain a 2-color image, by forming electrostatic latent images having the given color components of an original on a photoreceptor A chargeable to both polarities, and a screen photoreceptor B, holding both the receptors opposite to each other, and forming latent images different in polarity on the receptor A. CONSTITUTION:A 2-color copy is obtained from an original O having colors, such as red and black or red and blue. A photoreceptor 1 (A) is composed of 3 layers having a conductive base 13, a photoconductive layer 12, and an insulating layer 11. A photoreceptor 2 (B) is composed of 3 layers consisting of each elemental line 23 of a conductive screen mesh, each photoconductive layer 22, and each insulating layer 21 successively laminated on each line 23. The receptors 1, 2 are exposed to light reflected from the original O through 2-color separation filters 3, 4, and subjected to corona discharge to give onto the receptors 1, 2, for example, positive charge on the surface of the receptor 1 corresponding to the black BK and the red R of the image O, and zero charge to the area corresponding to its white area, and positive charge on the surface of the receptor 2 corresponding to its black BK. Then, the receptors 1, 2 are caused to face each other, negative charge I is given with a modulation corona charger 8 to modulate the surface of the receptor 1, giving negative potential to the area corresponding to the black BK, and positive potential to the area corresponding to the red R, and those areas are developed with toners Bt, Rt reverse to each other in polarity.