A photosensitive layer included in an electrophotographic photosensitive member contains at least a charge generating material, a hole transport material, and a binder resin. The hole transport material includes a compound (1). The binder resin includes a polyarylate resin having at least one repeating unit (10) and at least one repeating unit (11). Alternatively, the binder resin includes a polycarbonate resin having a repeating unit (20) and a repeating unit (21). The general formulas (1), (10), (11), (20), and (21) are as follows ##STR00001##

An electrophotographic photoreceptor includes a conductive substrate; and a photosensitive layer arranged on the conductive substrate and containing, as a charge generating material, any one material selected from the group consisting of titanyl phthalocyanines, metal-free phthalocyanines, chlorogallium phthalocyanines and hydroxygallium phthalocyanines; and, as an electron transporting material, a naphthalene tetracarboxylic acid diimide compound represented by Formula (1) below, where R.sup.1 and R.sup.2 each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group, an alkoxy group, an alkyl ester group, a phenyl group optionally having a substituent, a naphthyl group optionally having a substituent, or a halogen element; and R.sup.1 and R.sup.2 are optionally the same or different: ##STR00001##
The photoreceptor realizes a stable print density even in a low-temperature environment by suppressing a reduction in print density that is caused by potential fluctuation of the photoreceptor in the low-temperature environment.

The present disclosure provides an electrophotographic photosensitive member that reduces the accumulation of charge and the leakage which are caused by a repeated use in a long period of time. The electrophotographic photosensitive member has a support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein the undercoat layer contains a polyamide resin, and a titanium oxide particle, wherein the titanium oxide particle has been surfacetreated with an organosilicon compound, wherein the undercoat layer satisfies 1070, where represents a degree [%] of hydrophobicity of the titanium oxide particle which has been surfacetreated with the organosilicon compound; and the undercoat layer satisfies 0.015()0.040, where represents an average primary particle size [m] of the titanium oxide particles, and represents a weight percentage [wt %] of an Si element of the organosilicon compound with respect to the titanium oxide particle.

An image forming apparatus includes an image holding member including a conductive substrate, a photosensitive layer, and a protection layer; a charging unit; an electrostatic image forming unit; a developing unit that includes an electrostatic image developer having a toner and develops the electrostatic image to form a toner image; a transfer unit that transfers the toner image onto a surface of a recording medium; a fixing unit that fixes the toner image; and a cleaning unit that includes a cleaning blade. The toner includes toner particles and silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.

An electrophotographic photoconductor includes a conductive substrate; and a photosensitive layer provided on the conductive substrate and containing a charge generation material, a hole transport material, a first electron transport material, from 3% by mass to 40% by mass of a second electron transport material, a resin binder, and an inorganic oxide filler surface-treated with a silane coupling agent. In a dipole-dipole force component (a Hansen solubility parameter), the first electron transport material and the silane coupling agent have a difference of SPa<2.50; the second electron transport material and the silane coupling agent have a difference of SPb<2.50; and the first electron transport material and the second electron transport material have a difference of 0.30<SPc<1.00. In a London dispersion force component (a Hansen solubility parameter), the resin binder and the silane coupling agent have a difference of SPd<2.00.

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. The photosensitive layer (3) contains at least a charge generating material, a hole transport material, an electron transport material, and a binder resin. The charge generating material includes a metal-free phthalocyanine. The hole transport material includes a triphenylamine derivative represented by general formula (1) shown below. The electron transport material includes a quinone derivative represented by general formula (2) shown below. In general formula (1), R.sup.1, R.sup.2, R.sup.3, m1, m2, k, p, and q are the same as those described in the description. In general formula (2), R.sup.4, R.sup.5, and R.sup.6 are the same as those described in the description. ##STR00001##

The present invention provides a triphenylamine derivative represented by general formula (1). ##STR00001##
(In the formula, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group).

The present invention provides a triphenylamine derivative represented by general formula (1).

##STR00001##

(In the formula, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group.)

The present disclosure provides an electrophotographic photosensitive member that suppresses electric potential fluctuations in repeated use. The electrophotographic photosensitive member includes a support, a photosensitive layer and a protective layer, in this order, wherein the photosensitive layer includes a compound having a structure represented by formula (1), and the protective layer includes a resin having a structure represented by formula (2) and a structure represented by formula (3).

An electrophotographic photosensitive member which satisfies wear resistance and electrical properties, further has high image deletion prevention properties under a high temperature and high humidity environment, and a small potential variation under a low temperature and low humidity environment is provided. The electrophotographic photosensitive member includes a surface layer containing a polymerization product of a hole transporting compound having a specific structure.