A polyarylate resin is 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 hydrogen atom or a methyl group. r and s each represent an integer of at least 0 and no greater than 49. t and u each represent an integer of at least 1 and no greater than 50. r+s+t+u=100. r+t=s+u. X and Y each represent, independently of one another, a divalent group represented by chemical formula (1-1), chemical formula (1-2), chemical formula (1-3), or chemical formula (1-4). X and Y are different from one another. ##STR00001##

Provided is an electrophotographic member in which the increase in tackiness is small even in an environment of high temperature and high humidity. The electrophotographic member includes an electroconductive substrate and a surface layer, the surface layer contains resin including at least one of a urethane bond and an amide bond, the resin includes a cationic structure and an anionic structure in a molecule, and also includes a particular main-chain structure with hydrophobicity.

An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a polyester resin (1) having a dicarboxylic acid unit (A) represented by Formula (A) and a diol unit (B) represented by Formula (B), and an amount of a diol represented by Formula (1) in the charge transport layer is 10 ppm or less,

##STR00001## in Formula (A), n.sup.1 represents 1, 2, or 3, n.sup.1 pieces of m.sup.1's each independently represent 0, 1, 2, 3, or 4, m.sup.1 pieces of Ra.sup.1's each independently represent an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (B), Rb.sup.1 and Rb.sup.2 each independently represent a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, Rb.sup.3, Rb.sup.4, Rb.sup.5, Rb.sup.6, Rb.sup.7, Rb.sup.8, Rb.sup.9, and Rb.sup.10 each independently represent a hydrogen atom, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, an aralkyl group having 7 or more and 20 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, and Rb.sup.1 and Rb.sup.2 may be bonded to each other to form a cyclic alkyl group, in Formula (1), R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 each independently represent a hydrogen atom, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, an aralkyl group having 7 or more and 20 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, and R.sup.1 and R.sup.2 may be bonded to each other to form a cyclic alkyl group.

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, and a binder resin. The electron transport material includes a compound having a halogen atom and represented by a general formula (1), (2), (3), (4), or (5). The binder resin includes a polyarylate resin. The polyarylate resin includes at least one type of repeating unit each represented by general formula (11), at least one type of repeating unit each represented by general formula (12), and a terminal group represented by general formula (13). In general formula (13), R.sup.f represents a chain aliphatic group substituted by at least one fluoro group. A charge of calcium carbonate charged by friction between the photosensitive layer and the calcium carbonate is at least +8.0 C/g.

##STR00001## ##STR00002##

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##

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##

A polyarylate resin is 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 hydrogen atom or a methyl group. r and s each represent an integer of at least 0 and no greater than 49. t and u each represent an integer of at least 1 and no greater than 50. r+s+t+u=100. r+t=s+u. X and Y each represent, independently of one another, a divalent group represented by chemical formula (1-1), chemical formula (1-2), chemical formula (1-3), or chemical formula (1-4). X and Y are different from one another.

##STR00001##

The present invention provides an electrophotographic electro-conductive member containing an ion-exchange group structure in an electro-conductive layer, whereby the bleeding of an ionic conductive agent to the surface of the electro-conductive layer is suppressed and reduction in electro-conductivity caused by electrification is low. For this purpose, the electrophotographic member of the present invention is an electrophotographic member having an electro-conductive mandrel and an electro-conductive layer, wherein the electro-conductive layer contains a resin having any one or more of partial structures represented by the specific formulas (1) to (7) in the molecule, and an anion.

A triarylamine derivative represented by general formula (1) below. In the general formula (1), R.sub.1, R.sub.2, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, and R.sub.9 each represent, independently from one another, a hydrogen atom, an optionally substitute 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, R.sub.3 represents an alkyl group having a carbon number of at least 1 and no greater than 4, X represents an alkylene group having a carbon number of at least 1 and no greater than 6 or an oxygen atom, and n represents an integer of 1 to 3. ##STR00001##

The invention is to provide an image forming apparatus and an electrophotographic cartridge, which are free from problems of cleaning failure, filming, soiling, residual images (ghosts), fogging, density reduction, noise and the like and which can provide high-definition images even when a toner having a small particle size and having a high degree of circularity is used and even when a photoreceptor having a small outer diameter is used. An image forming apparatus comprising: an electrophotographic photoreceptor containing a conductive support and a photosensitive layer on the conductive support, a charging unit for charging the electrophotographic photoreceptor, an imagewise exposing unit for imagewise exposing the charged electrophotographic photoreceptor to form an electrostatic latent image thereon, a developing unit for developing the electrostatic latent image with a toner, and a transferring unit for transferring the toner from the electrophotographic photoreceptor to a receiving unit, wherein the outer diameter of the electrophotographic photoreceptor is 20 mm or less, the photosensitive layer contains a polyarylate resin, and the toner satisfies the specific requirements (1) and (2).