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##

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 hole transporting layer containing a polyester resin having a structural unit expressed by formula (1) as a hole transporting substance.

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 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 Ω.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.

An electrophotographic photoreceptor includes a charge generation layer including a charge generating material and a hindered phenol antioxidant, and a charge transport layer including a charge transport material represented by formula (CT1) and a charge transport material represented by formula (CT2):

##STR00001##

wherein R.sup.C11, R.sup.C12, R.sup.C13, R.sup.C14, R.sup.C15 and R.sup.C16 each independently represent a hydrogen atom, a halogen atom, an alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, or an aryl group having from 6 to 30 carbon atoms, and n and m each independently represent 0, 1, or 2; and

##STR00002##

wherein R.sup.C21, R.sup.C22 , and R.sup.C23 each independently represent a hydrogen atom, a halogen atom, an alkyl group having from 1 to 10 carbon atoms, an alkoxy group having from 1 to 10 carbon atoms, or an aryl group having from 6 to 10 carbon atoms.

A compound has a structure represented by the following formula (C1): ##STR00001##
wherein R.sub.a1, R.sub.a2, R.sub.a3, R.sub.a41, R.sub.a42, R.sub.a43, R.sub.a44, R.sub.a45, R.sub.a5, R.sub.a6, R.sub.a7, R.sub.a8, R.sub.a9, R.sub.a10, and R.sub.a11 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aralkyl group, an aryl group, a cyano group, a halogen atom, or a group obtained by combining two or more of the above groups, and a combination of R.sub.a1 and R.sub.a2, R.sub.a41 and R.sub.a42, R.sub.a42 and R.sub.a43, R.sub.a43 and R.sub.a44, R.sub.a44 and R.sub.a45, R.sub.a5 and R.sub.a6, R.sub.a8 and R.sub.a9, or R.sub.a10 and R.sub.a11 each independently may form a ring.

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 photoreceptor includes: a conductive substrate; a charge generation layer that is disposed on the conductive substrate and contains a resin, a phthalocyanine pigment, and a compound represented by the following Formula (BP); and a charge transport layer that is disposed on the charge generation layer and contains a charge transport material,

##STR00001##

wherein R.sup.B1, R.sup.B2 and R.sup.B3 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having from 1 to 10 carbon atoms, an alkoxy group having from 1 to 10 carbon atoms, or an aryl group having from 6 to 10 carbon atoms.