A photoconductor including a conductive support, an undercoat layer, a charge-generating layer, and a charge-transporting layer, at least the undercoat layer, the charge-generating layer, and the charge-transporting layer being disposed on the conductive support in an order mentioned, wherein the undercoat layer includes a binder resin and metal oxide particles, and the charge-generating layer includes a binder resin, a titanyl phthalocyanine pigment, and a salicylic acid derivative.

A quinone derivative represented by general formula (1) where, in the general formula (1), chemical groups R.sub.1 each represent, independently of one another, an alkyl group, a cycloalkyl group, an alkoxy group, an aralkyl group, or an aryl group, and R.sub.2 represents an alkyl group, an aralkyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heterocyclic group. ##STR00001##

A quinone derivative represented by general formula (1), ##STR00001##
where, in the general formula (1), R.sub.1 and R.sub.2 each represent, independently of one another, an alkyl group, a cycloalkyl group, an alkoxy group, an aralkyl group, or an aryl group, R.sub.3 represents a halogen atom, an alkyl group, an alkoxy group, or an aryl group, m represents an integer of no less than 0 and no greater than 4, and when m represents an integer of no less than 2, chemical groups R.sub.3 may be the same as or different from one another.

In a positively chargeable single-layer electrophotographic photosensitive member, a photosensitive layer contains at least a hole transport material, and particles of a first resin. A compound represented by general formula (1) is contained as the hole transport material. In the general formula (1), R.sub.1 represents an alkyl group having a carbon number of at least 2 and no greater than 4. R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 each represent, independently of one another, a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 4. Ar.sub.1 and Ar.sub.2 each represent, independently of each other, a hydrogen atom or an optionally substituted aryl group having a carbon number of at least 6 and no greater than 20. At least one of Ar.sub.1 and Ar.sub.2 represents an optionally substituted aryl group having a carbon number of at least 6 and no greater than 20. ##STR00001##

An electrophotographic photoreceptor includes a conductive substrate and a single-layer photosensitive layer on the conductive substrate. The photosensitive layer includes a binder resin, at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, a hole transporting material, and an electron transporting material and has a Martens hardness Hm of 170 N/mm.sup.2 or more and 200 N/mm.sup.2 or less.

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.

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 photoconductor includes: a conductive substrate; and a single-layer-type photoconductive layer that is provided on the conductive substrate and contains a binder resin, a charge generating material, a hole transporting material, and an electron transporting material, in which a volume resistivity of the photoconductive layer after wear is 5.0×10.sup.10 Ω.Math.cm or more and 2.0×10.sup.11 Ω.Math.cm or less when a ratio of a thickness of the photoconductive layer after wear to a thickness of the photoconductive layer before wear (the thickness of the photoconductive layer after wear/the thickness of the photoconductive layer before wear) is 0.8.

There is provided an electrophotographic photoreceptor including: a conductive support; and a photosensitive layer and a protective layer containing a cured product obtained by curing a curable compound, which are sequentially disposed on the conductive support. An area ratio A/B is 0.0045 or less, where A is an absorbance area at a wavelength of 1647 cm.sup.−1 to 1627 cm.sup.−1 and B is an absorbance area of a peak at a wavelength of 1800 cm.sup.−1 to 1647 cm.sup.−1 in an infrared absorption spectrum measurement of the protective layer. The photosensitive layer contains at least a hole transport material (HTM) and a radical acceptor compound. The electrophotographic photoreceptor is an electrophotographic photoreceptor including a protective layer with a high curing degree and having good initial electrical characteristics, excellent strong exposure characteristics, and excellent transfer repeatability.

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer on the conductive substrate, and a photosensitive layer on the undercoat layer, in which the undercoat layer is formed of a cured product of a composition that contains a reactive group-containing triarylamine compound, a curing agent, and an electron transport material and that has a butyral resin content of 0 mass % or more and 5 mass % or less relative to all solid components in the undercoat layer.