Ishihara Sangyo Kaisha, Ltd.

Hiroshi Ichida

Sadao Murasawa

Hajime Murakami

Kei Takahata

Kenichi Ichimura

Mizuho Okada

Takao Nakayama

The present invention aims at materialization of reproduction of an image of high quality by the color electrophotography process of the EF system according to a specific procedure of effecting back surface grounding of a photosensitive material sheet comprising a photosensitive layer consisting of titanium dioxide and a specific base sheet comprising a conductive support constituted by a conductive layer laminated on a highly smooth surface and highly specific resistivity base sheet on the basis of a conductive conveyor.

Color electrophotographic process uses layered photosensitive element

In practicing multi-step reproduction of color image by electrophotography using an electrophotographic photosensitive material prepared by overlaying a photosensitive layer composed mainly of titanium dioxide and a binder on an electroconductive substrate, exposure to an optical image is first carried out, then positive corona charging is carried out to form a positive electrostatic latent image and subsequently developing is carried out. Further, prior to the exposure to an optical image, negative corona charging and/or AC corona charging are additionally carried out. By this electrophotographic process effectively utilizing the photomemory effect of titanium dioxide, multi-color images can be produced, and an image having good contrast can be reproduced easily and stably.

Multicolor electrophotographic process using TiO.sub.2

A liquid developing apparatus for developing a latent electrostatic image by contacting a liquid developer with an electrophotographic photoreceptor bearing said latent electrostatic image on the undersurface thereof while moving the electrophotographic photoreceptor horizontally over a liquid developing bath. In the apparatus, a number of horizontally spaced developing electrodes in the form of bars having a vertical cross-section in the shape of a tetragon are disposed in the bath very near the undersurface of the photoreceptor. When the liquid developing apparatus is used, an electrophotographic image can be obtained having a high quality but being free from non-uniformity of image density, edge effect and flow of image or streaks.

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Shiga, Japan

Hiroshi Ichida