JPS5587175A - Method and apparatus for electrophotography - Google Patents

Abstract

PURPOSE:To facilitate formation of electrostatic latent image of composite image, by charging the surface of insulating layer and applying first image forming radiation simultaneously, and applying AC destaticizing and second image forming radiation simultaneously, then exposing the entire surface of the insulating layer. CONSTITUTION:A photosensitive plate 40 is composed of conductive supporting body 1, photoconductive layer 2 and insulating layer 3. The surface of this insulating layer 3 is charged by a charging means 41, and a first image forming radiation is applied simultaneously. Then, destaticizing with an AC destaticizing means 42, a second image forming radiation is applied simultaneously. Further, the entire surface of the insulating layer 3 is exposed by a full exposure means 43. Thus, a latent image of a composite image may be obtained. In this electrostatic latent image, only the bright part by radiation of first optical image a and the dark part by radiation of second optical imae b have a large negative potential, while the other parts have almost zero potential. When developed with toners of positive polarity and negative polarity, the images will changes as shown in c and d, respectively. Thus, an electrostatic image of a composite image may be easily obtained.