JPS55118044A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE: To obtain positive-positive and negative-positive copying images through changing over of charging polarities by forming the intermediate insulation film of the electrophotographic receptor comprising subsequently laminating an intermediate layer, photoconductive layer and surface insulation layer on a conductive substrate by using oil-modified polyurethane resin.

CONSTITUTION: An intermediate layer 2 is formed by oil-modified polyurethane resin (clear for floor made by Nippon Paint, etc.) to a film thickness from 0.1 to 20μ on a conductive substrate (Al plate or the like) 1, on which a photoconductive layer 3 of amorphous Se or the like is formed to a thickness from about 5 to 200μ, and further a surface insulation layer 4 of high resistance and abrasion resistance such as of polyester is formed, whereby the photoreceptor is made. The layer 4 of this photoreceptor is subjected to primary charging to positive or negative by a corona charger 5, thence to uniform exposure 6 then to the secondary charging at the polarity opposite from the primary one with a corona charger 7, after which it is subjected to the image exposure 9 of the line original 8, whereby the positive images are made in case the primary charging is positive and the negative imges in case it is negative, the latter owing to the peripheral electric field effect. The negative images are effective for line images in this case. The formation of the negative images of wide region images simply necessitates the use of developing electrode.

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