ELECTROPHOTOGRAPHIC PHOTORECEPTOR, IMAGE FORMING APPARATUS, AND PROCESS CARTRIDGE

摘要

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of preventing the occurrence of a memory image due to transfer and exposure and outputting the high-grade image, even with repeated image formation over a long period, in an image forming apparatus that uses electrophotographic photoreceptor having photosensitivity of both the positive and negative polarities. SOLUTION: The electrophotographic photoreceptor, having a photosensitive layer on at least a conductive support, includes a charge generating material, and a charge transfer material expressed by Formula (1) (where R1, R2 each independently denotes a group selected from among a group consisting of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cyclyalkyl group, and substituted or unsubstituted aralkyl group; R3 to R10, each independently denotes a group selected from among a group consisting of a hydrogen atom, halogen atom, cyano group, nitro group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cyclyalkyl group, and substituted or unsubstituted aralkyl group) and has the photosensitivity of both the positive and negative polarities, in which a ratio E1/2 (negative)/E1/2 (positive) of the photosensitivity E1/2 (positive), E1/2 (negative) at the respective polarities is 0.5 to 3.0. Here, E1/2 is the exposure energy (μJ/cm2) per photoreceptor surface 1 cm2necessary for the surface potential to be reduced by a half, through the exposure with monochromatic light of 780 nm, after charging of the electrophotographic photoreceptor to±800V. COPYRIGHT: (C)2007,JPO&INPIT