An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer containing at least a charge generating material, an electron transport material, a hole transport material, and a binder resin. The electron transport material includes a naphthoquinone derivative represented by general formula (1). An amount of triboelectric charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer (3) is at least +7 C/g. In general formula (1), R.sup.11 and R.sup.12 are respectively the same as R.sup.11 and R.sup.12 described in the description.

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An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) contains a charge generating material and a compound 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 C1-20 alkyl group optionally having at least one of a C6-14 aryl group optionally having a substituent and a C2-20 alkoxycarbonyl group; a C6-14 aryl group optionally having a C1-20 alkyl group; a C3-10 cycloalkyl group; or a C1-6 alkoxy group.

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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. ##STR00001##

The present invention relates to an electrophotographic photoreceptor comprising: a conductive support; and a photosensitive layer on the conductive support, wherein the photosensitive layer contains a charge transport substance, a binder resin, and a compound which has a molecular weight of equal to or less than 350, and is represented by General Formula (1).

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin contains a polyarylate resin. The polyarylate resin is represented by general formula (1). The hole transport material contains a compound represented by general formula (HTM1), (HTM2), (HTM3), (HTM4), (HTM5), (HTM6), or (HTM7). The photosensitive layer has a scratch resistance depth of no greater than 0.50 m. The photosensitive layer has a Vickers hardness of at least 17.0 HV. ##STR00001## ##STR00002##

The present invention relates to an electrophotographic photoreceptor for positive charging, the photoreceptor comprising: a conductive support; and a single-layer type photosensitive layer disposed on the conductive support, the single-layer type photosensitive layer containing a binder resin, a compound (1) having hole transporting ability, and a compound (2) having electron-transporting ability, wherein the level Ah of a compound having a highest energy level of HOMO in the compound (1), the level BI of a compound having a lowest energy level of LUMO in the compound (2), and an energy level Ch of HOMO of another compound C which has a molecular weight of 500 or less and is contained in the photosensitive layer satisfy specific equations.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer and contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin has a viscosity average molecular weight of at least 25,000 and no greater than 50,000. A strain at break of the photosensitive layer is at least 4.9% and no greater than 13.0%. A scratch resistant depth of the photosensitive layer is no greater than 0.50 m.

An image forming apparatus includes an electrophotographic photoreceptor having a photosensitive layer that includes at least one of a hindered phenol antioxidant and a benzophenone ultraviolet absorber, a charging device, an electrostatic latent image forming device, a developing device, and a transfer device that includes an intermediate transfer belt whose electric field dependence of a volume resistivity is 0.003 or less (log .Math.cm)/V in a voltage range of from 500 V to 1,000 V, and transfers a toner image formed on a surface of the electrophotographic photoreceptor onto a recording medium through the intermediate transfer belt and erases charges from the surface of the electrophotographic photoreceptor by applying current to the electrophotographic photoreceptor after the toner image formed on the surface of the electrophotographic photoreceptor has been transferred onto the intermediate transfer belt.

A quinone derivative is represented by general formula (1). In general formula (1), at least one of R.sup.1-R.sup.3 and at least one of R.sup.4-R.sup.6 each represent, independently of one another, an alkyl group having 4 to 10 carbon atoms or an alkyl group having 2 to 5 carbon atoms that has an aryl group having 6 to 14 carbon atoms. All other of R.sup.1-R.sup.3 and all other of R.sup.4-R.sup.6 each represent, independently of one another, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms. ##STR00001##

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 polycarbonate resin has a terminal group having a fluoro group and represented by general formula (10). 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. The photosensitive layer has a Vickers hardness of at least 17.0 HV at 45 C.

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