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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An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer of a single-layer type disposed on the conductive substrate. The photosensitive layer has an absorption coefficient of 0.008 or less at a wavelength of 1000 nm and contains a binder resin, a charge generating material, an electron transporting material, and a hole transporting material. The charge generating material is at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment and is contained in an amount of 0.9% by weight or more and 1.8% by weight or less relative to the binder resin.

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 photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer has a single-layer structure and contains a charge generating material and a compound represented by general formula (1) shown below. In the general formula (1), R.sup.1 and R.sup.2 each represent, independently of each other: an alkyl group having 1 to 12 carbon atoms and optionally substituted by an alkoxy group having 1 to 6 carbon atoms or an alkoxycarbonyl group having 2 to 6 carbon atoms; an aryl group having 6 to 14 carbon atoms and optionally substituted by an alkyl group having 1 to 6 carbon atoms; an aralkyl group having 7 to 20 carbon atoms; or a cycloalkyl group having 3 to 10 carbon atoms. X represents S or SO.sub.2.

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A coating film of a coating liquid for a surface layer, the coating liquid containing a hole transporting compound having a chain-polymerizable functional group and a compound having a specified structure, is cured to thereby form a surface layer of an electrophotographic photosensitive member.

A quinone derivative is represented by general formula (1), (2), or (3). In general formulae (1), (2), and (3), R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.21, R.sup.22, R.sup.23, and R.sup.24 each represent, independently of one another, a hydrogen atom, a cyano group, a halogen atom, an optionally substituted alkyl group having a carbon number of 1-6, or an optionally substituted alkoxy group having a carbon number of 1-6. R.sup.5, R.sup.6, R.sup.15, R.sup.16, R.sup.25, and R.sup.26 each represent, independently of one another, an optionally substituted alkyl group having a carbon number of 1-6, an optionally substituted alkoxy group having a carbon number of 1-6, an optionally substituted aryl group having a carbon number of 6-14, an optionally substituted aralkyl group having a carbon number of 7-12, or an optionally substituted cycloalkyl group having a carbon number of 3-10. ##STR00001##

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 photoreceptor for electrophotography and an electrophotography device having the same reduces wear loss of the photoreceptor surface and stably obtaining a favorable image for long time. The photoreceptor for electrophotography includes a conductive substrate and a charge transport layer provided on the conductive substrate. The charge transport layer contains a charge transport material, a resin binder, and an inorganic oxide filler surface-treated with a silane coupling agent. A difference (SPa) in a dipole-dipole force component that is a Hansen solubility parameter between the charge transport material and the silane coupling agent satisfies a relationship SPa<1.0. A difference (SPb) in a London dispersion force component that is a Hansen solubility parameter between the resin binder and the silane coupling agent satisfies a relationship SPb<2.5.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer containing a charge generating material, a hole transport material, a quinone derivative, and a binder resin. The quinone derivative is represented by general formula (1) or (2), where R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 each represent, independently of one another, a hydrogen atom, an alkyl group having a carbon number of at least 1 and no greater than 12, an aryl group that has a carbon number of at least 6 and no greater than 14 and that may have an alkyl group having a carbon number of at least 1 and no greater than 6, an aralkyl group having a carbon number of at least 7 and no greater than 12, or a cycloalkyl group having a carbon number of at least 3 and no greater than 10. Z represents an oxygen atom or a sulfur atom. ##STR00001##

Electrophotographic photoreceptor including a conductive substrate, an organic photosensitive layer on an outer peripheral surface of the conductive substrate, and an inorganic protective layer on an outer peripheral surface of the organic photosensitive layer, the inorganic protective layer containing gallium and oxygen. A volume resistivity of an inner region of the inorganic protective layer, the inner region extending 0.2 m or about 0.2 m from an inner peripheral surface of the inorganic protective layer in a thickness direction, and a volume resistivity of an outer region of the inorganic protective layer, the outer region extending 0.2 m or about 0.2 m from an outer peripheral surface of the inorganic protective layer in the thickness direction, are both 6.010.sup.7 .Math.cm or more and 4.010.sup.8 .Math.cm or less or about 6.010.sup.7 .Math.cm or more and about 4.010.sup.8 .Math.cm or less.