JPS55100570A - Multicolor electrophotographic copying method - Google Patents

Abstract

PURPOSE: To prevent framing of the picture image by other color, by bringing the potential of other latent images close to zero when developing one latent image.

CONSTITUTION: A laminated photoreceptor P consisting of a first photoconductive layer 2 possessing photosensitivity to blue and red and not to green in positive charging and the second photoconductive layer 3 possessing photosensitivity to green and not to blue and red in negative charging is negatively and uniformly charged primarily on a conductive substrate 1, and the surface potential thereof is reduced to negative, and, at the same time, a positive charge equal in quantity to the negative charge on the surface is held near the boundary between the first photoconductive layer 2 and the second photoconductive layer 3. Secondary charge is then applied uniformly by means of a corona discharger 5 to neutralize, leaving part of the negative charge on the surface, and an optical image of the original possessing black color part 6a, white color ground part 6b, and red color part 6c is radiated. Afterwards, a positively charged red color toner 7 is supplied. As a result, the red color part of the original 6 is reproduced, while the potential of the latent image corresponding to the black color is neutralized and lowered, so that the red color toner 7 may not be adsorbed in the circumference of the latent image corresponding to the black color.

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