An electrophotographic photoreceptor includes a conductive substrate and a single-layer-type photosensitive layer on the conductive substrate. The single-layer-type photosensitive layer contains a binder resin, a charge generating material, an electron transporting material, and two hole transporting materials having different redox potentials. The two hole transporting materials are a hole transporting material A and a hole transporting material B that has a redox potential lower than that of the hole transporting material A. The ratio A/B of a weight of the hole transporting material A to a weight of the hole transporting material B is about 12/1 or more and about 36/1 or less.

An electrophotographic photosensitive member includes a conductive base, and a single-layer photosensitive layer disposed directly on the conductive base and containing a charge generation material. A difference between a work function of the conductive base and an electron affinity of the charge generation material is in a range of from about 0.1 to about +0.1 eV. A difference between a current Ia and a current Ib is in a range of from about 5.510.sup.8 to about 9.210.sup.8 [A/cm.sup.2] when a gold electrode is provided on the photosensitive layer, where the current Ia is a current when an electric field is applied by applying a voltage so that the gold electrode becomes positive, and the current Ib is a current when an electric field is applied by applying a voltage so that the conductive base becomes positive.

An electrophotographic photosensitive member includes a photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, and a binder resin. The binder resin contains a polyarylate resin represented by general formula (1). In general formula (1), r and s each represent an integer of at least 0 and no greater than 49 and t and u represents an integer of at least 1 and no greater than 50. Furthermore, r+s+t+u=100 and r+t=s+u. X and Y each represent, independently of one another, a divalent group represented by chemical formula (1-1), (1-2), (1-3), or (1-4).

##STR00001##

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 polyatylate 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.

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An electrophotographic photoreceptor comprising at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer is a laminate having a charge transport layer and a charge generation layer, the charge transport layer contains four or more types of compounds each having a maximum absorption wavelength falling within a wavelength range of from 300 nm to 600 nm in a tetrahydrofuran solution at 25? C., and maximum absorption wavelengths falling within the wavelength range of at least four types of the compounds of said four or more types of the compounds are separated from each other by 10 nm or more.

An electrophotographic photoreceptor includes a conductive substrate including an outer peripheral surface treated with a silazane; and a photosensitive layer on the outer peripheral surface of the conductive substrate. The photosensitive layer includes a charge generating material and a charge transporting material.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer contains at least a charge generating material, a hole transport material, and a binder resin. The hole transport material is a compound represented by the following general formula (1). The binder resin is a resin represented by the following general formula (2). In general formula (1), R.sub.1 and R.sub.3 each independently represent an alkyl group, an aryl group, an aralkyl group, or an alkoxy group; and R.sub.2 and R.sub.4 each independently represent an alkyl group, or an alkoxy group. In general formula (2), R.sub.23, R.sub.24, and R.sub.25 each independently represent a hydrogen atom, or a C.sub.1-4 alkyl group, at least one of R.sub.23, R.sub.24, and R.sub.25 representing a C.sub.1-4 alkyl group; p+q=1.00, and 0.35p<1.00; and n represents 2 or 3. ##STR00001##

An electrophotographic photoreceptor includes a conductive substrate and a single-layer-type photosensitive layer on the conductive substrate. The single-layer-type photosensitive layer contains a binder resin, a charge generating material, an electron transporting material, and a hole transporting material. The single-layer-type photosensitive layer has a concentration ratio (A/B) of 0.7 or more and 1.0 or less, where the concentration ratio (A/B) is a ratio of a concentration A of the electron transporting material relative to the binder resin measured from a surface of the photosensitive layer remote from the conductive substrate to a concentration B of the electron transporting material relative to the binder resin measured from a surface of the photosensitive layer close to the conductive substrate.

A benzidine derivative is represented by general formula (1). In the general formula (1), R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, and R.sub.10 each represent, independently of one another, a hydrogen atom, a halogen atom, an optionally substituted 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. n represents an integer of at least 0 and no greater than 2. ##STR00001##

A triphenylamine derivative is represented by general formula (1). In the general formula (1): R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, and R.sub.10 each represent, independently of one another, a hydrogen atom, an optionally substituted 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, an optionally substituted alkenyl group having a carbon number of at least 2 and no greater than 6, or an optionally substituted aryl group having a carbon number of at least 6 and no greater than 14; m represents an integer of at least 1 and no greater than 3; and n represents an integer of at least 0 and no greater than 2. ##STR00001##