An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer having a single-layer structure. The photosensitive layer contains a charge generating material, an electron transport material, a polycarbonate resin, and a hole transport material. The electron transport material includes a compound having a halogen atom and represented by general formula (1), (2), (3), (4), or (5). The hole transport material includes a compound represented by general formula (20), (21), (22), (23), (24), (25), (26), or (27). A charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer is at least +6.5 C/g. A Vickers hardness of the photosensitive layer at 45 C. is at least 17.0 HV.

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The present invention is to provide a charge transport substance having high resistance to stress within electrophotographic processes, an electrophotographic photoreceptor which has excellent high-speed responsiveness, shows a sufficient residual potential, and has high resistance to stress within electrophotographic processes, an electrophotographic cartridge, and an image-forming apparatus. The invention provides a charge transport substance having a specific structure. The invention further provides an electrophotographic photoreceptor including a photosensitive layer which contains the charge transport substance having a specific structure, an electrophotographic cartridge, and an image-forming apparatus, equipped with this electrophotographic photoreceptor.

An electrophotographic photoreceptor includes a conductive substrate; and a photosensitive layer arranged on the conductive substrate and containing, as a charge generating material, any one material selected from the group consisting of titanyl phthalocyanines, metal-free phthalocyanines, chlorogallium phthalocyanines and hydroxygallium phthalocyanines; and, as an electron transporting material, a naphthalene tetracarboxylic acid diimide compound represented by Formula (1) below, where R.sup.1 and R.sup.2 each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group, an alkoxy group, an alkyl ester group, a phenyl group optionally having a substituent, a naphthyl group optionally having a substituent, or a halogen element; and R.sup.1 and R.sup.2 are optionally the same or different:

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The photoreceptor realizes a stable print density even in a low-temperature environment by suppressing a reduction in print density that is caused by potential fluctuation of the photoreceptor in the low-temperature environment.

An electrophotographic photoreceptor includes a conductive support and a single-layer photosensitive layer. The conductive support has an outer peripheral surface with a maximum surface roughness height (Rmax) of about 4.0 m or less, and the outer peripheral surface has a recess with a depth-to-aperture size ratio (depth/aperture size) of about 0.03 or more and about 0.12 or less. The single-layer photosensitive layer is disposed on the conductive support and has a thickness of about 20 m or more and a modulus of elasticity of about 4.5 GPa or more.

A polyarylate resin is represented by general formula (1) shown below. In general formula (1), R.sup.1 represents a hydrogen atom or methyl group. R.sup.2 and R.sup.3 each represent a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 4. R.sup.2 and R.sup.3 are not the same as one another. When R.sup.1 represents a hydrogen atom, R.sup.2 and R.sup.3 are not bonded to one another. When R.sup.1 represents a methyl group, R.sup.2 and R.sup.3 are optionally bonded to one another to form a ring. r and s each represent a number greater than or equal to 0 and less than or equal to 49. t and u each represent a number greater than or equal to 1 and less than or equal to 50. r+s+t+u=100. r+t=s+u.

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A polyarylate resin includes at least one type of repeating unit represented by a general formula (1), at least one type of repeating unit represented by a general formula (2), and a terminal group represented by a general formula (3). R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each represent, independently of one another, a hydrogen atom or a methyl group. R.sup.5 and R.sup.6 each represent, independently of each other, a hydrogen atom or a C.sub.1-4 alkyl group. R.sup.5 and R.sup.6 may bond together to represent a C.sub.5-7 cycloalkylidene group. X.sup.1 represents a divalent group represented by a chemical formula (2A), (2B), (2C), or (2D) with the proviso that when only one type of repeating unit represented by the general formula (2) is included, X.sup.1 does not represent a divalent group represented by the chemical formula (2D). R.sup.f represents a chain aliphatic group having at least one fluoro group.

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An electrophotographic photosensitive body includes at least a photosensitive layer and a protective layer sequentially laminated on an electroconductive support, wherein the protective layer has a domain containing perfluoropolyether.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer contains at least a charge generating material, a charge transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin is represented by general formula (1) shown below. In general formula (1), X represents a divalent group represented by chemical formula (1-1), (1-2), (1-3), or (1-4) shown below. ##STR00001##

A polyarylate resin is represented by general formula (1) shown below. In general formula (1), R.sup.1 and R.sup.2 each represent, independently of one another, a hydrogen atom or a methyl group. r and s each represent an integer of at least 0 and no greater than 49. t and u each represent an integer of at least 1 and no greater than 50. r+s+t+u=100. r+t=s+u. X and Y each represent, independently of one another, a divalent group represented by chemical formula (1-1), chemical formula (1-2), chemical formula (1-3), or chemical formula (1-4). X and Y are different from one another.

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A triarylamine derivative represented by general formula (1) below. In the general formula (1), R.sub.1, R.sub.2, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, and R.sub.9 each represent, independently from one another, a hydrogen atom, an optionally substitute alkyl group having a carbon number of at least 1 and no greater than 6, an optionally substituted alkoxy group having a carbon number of at least 1 and no greater than 6, or an optionally substituted aryl group having a carbon number of at least 6 and no greater than 14, R.sub.3 represents an alkyl group having a carbon number of at least 1 and no greater than 4, X represents an alkylene group having a carbon number of at least 1 and no greater than 6 or an oxygen atom, and n represents an integer of 1 to 3. ##STR00001##