JPS5536870A - Partially coloring two color electrophotography - Google Patents

Abstract

PURPOSE: To color copy sharply the necessary part of a black original, by charging the photoreceptor surface corresponding to the desired part of the original image to a polarity reverse to that of a latent image for a black image by a specified method in two-color electrophotography.

CONSTITUTION: For example, in red coloring, panchromatic first photoconductive layer 2 is provided on conductive substrate 1 and second photoconductive layer 3 sensitive to blue green and insensitive to red is formed on layer 2 to form a photoreceptor. The photoreceptor surface is uniformly negatively charged to catch the equal amount of positive charge in the interlayer of layers 2 and 3, and then, the surface is charged reversely in polarity to render the charge on the whole surface positive, leaving negative charge on part of the surface. Subsequently, the part desired to be colored red of original 6 is covered with filter 7 for reflecting red and transmitting blue green, the photoreceptor surface is exposed to light reflected from whole original 6 illuminated with white light sources 8 and 9, the surface voltage is made zero on area Pa corresponding to the ground, positive on area Pb corresponding to black, and negative on area Pd corresponding to red, and the surface is developed with black toner 12 charged negatively and with red toner 13 charged positively.

COPYRIGHT: (C)1980,JPO&Japio