Mitsubishi Chemical Corporation

Mitsubishi Kasei Corporation

Itaru Ogawa

Mamoru Nozomi

Satoshi Kato

Masayuki Hiroi

Shigenori Otsuka

Hiroaki Takamura

Takahiro Choda

Kazuyuki Mito

An electrophotographic photoreceptor having a photosensitive layer containing a binder resin on an electroconductive substrate, wherein at least a part of the binder resin in the photosensitive layer is a polycarbonate resin having a structure of the following formula (1) as main repeating units and a structure of the following formula (2) at one or each terminal and having a viscosity-average molecular weight of from 10,000 to 300,000: ##STR1## where, in the formula (1), each of Y.sup.1 to Y.sup.8 which are independent of one another, is a hydrogen atom, a C.sub.1-10 saturated aliphatic hydrocarbon group, a C.sub.3-10 unsaturated aliphatic hydrocarbon group, a halogen atom, a halogenated alkyl group, a C.sub.1-10 alkoxy group or a C.sub.6-20 aromatic hydrocarbon group which may be substituted, X.sup.1 is ##STR2## an aromatic ring, a single bond, a lactone or fluorene, each of R.sup.1 to R.sup.7 which are independent of one another, is a hydrogen atom, a C.sub.1-10 saturated aliphatic hydrocarbon group which may have a substituent, a C.sub.3-10 unsaturated aliphatic hydrocarbon group which may have a substituent, a halogen atom, an alkoxy group or a C.sub.6-20 aromatic hydrocarbon group which may have a substituent, Z is a C.sub.3-20 substituted or unsubstituted aliphatic hydrocarbon group, a is an integer of from 0 to 4, l is an integer of from 1 to 6, and m is an integer of from 2 to 20, and, in the formula (2), R.sup.13 is an aliphatic and/or aromatic bivalent organic residue, W is a single bond, O, CO, COO, NH, NHCO, S, SO or SO.sub.2, each of R.sup.8 to R.sup.12 which are independent of one another, is a C.sub.1-10 saturated aliphatic hydrocarbon group which may have a substituent or a C.sub.6-20 aromatic hydrocarbon group which may have a substituent, and n is an integer of from 1 to 500.

Electrophotographic photoreceptor

An electrophotographic copying method, which comprises conducting each process of at least charging, exposing to light, developing and transferring, characterized in that the photoreceptor has at least an undercoat layer and a photosensitive layer on an electroconductive substrate, wherein the undercoat layer contains a semiconductive material having a band gap of at least 2.2 eV and a binder resin, the photosensitive layer contains at least a phthalocyanine compound as a charge-generation material, and image-formation is carried out from the first revolution of the photoreceptor.

Electrophotographic copying method and electrophotographic copying

The disclosure describes an electrophotographic copying process for reversal development using a laminate-type electrophotographic photoreceptor having laminated on an electroconductive support a charge generation layer containing a phthalocyanine compound and a charge transport layer, and capable of forming plural copies of image, comprising at least charging step, image exposing step, developing step, transferring step and charge erasing step by light, wherein the charge erasure by light is not conducted in image formation by the first rotation of photoreceptor and is conducted in image formation by the second and succeeding rotations of photoreceptor.

Electrophotographic copying process for reversal development

Disclosed herein is an electrophotographic apparatus and method which repeatedly use an electrophotographic photoreceptor having on an electroconductive support a photosensitive layer formed by dispersing a charge-generating substance in a binder containing a charge-transporting substance and a binder resin and a means or step for optically erasing the residual charges on the photoreceptor after transfer, the main component of a light used in the means for optically erasing the residual charges having the wavelength range which satisfies the condition defined in the formula (1):

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Yokohama, Japan

Itaru Ogawa