The present invention relates to an electrophotographic photoreceptor comprising: a conductive support; and a photosensitive layer disposed on the conductive support, wherein the photosensitive layer includes a polyester resin containing a dihydric phenol residue and a dicarboxylic acid residue, and the dihydric phenol residue includes at least one dihydric phenol residue selected from the group of the specific dihydric phenol residues, and the other specific dihydric phenol residue.

A fluorine-containing resin particle contains 0 or more and 30 or less carboxyl groups per 10.sup.6 carbon atoms and 0 ppm or more and 3 ppm or less of a basic compound.

A photosensitive layer of an electrophotographic photosensitive member is a single layer and contains a charge generating material, a hole transport material, a first electron transport material, a second electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units (1), (2), (3), and (4).

##STR00001##

A percentage of the number of repeats of the repeating unit (3) relative to the total of the number of repeats of the repeating units (1) and the number of repeats of the repeating unit (3) is greater than 0% and less than 20%. The first electron transport material includes a compound represented by formula (A15) or (A16).

##STR00002##

The second electron transport material includes a compound represented by formula (B10), (B11), (B12), (B13), or (B14)

##STR00003##

A single-layer photosensitive layer included in an electrophotographic photosensitive member contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units (1), (2), (3), and (4).

##STR00001##

The percentage of the number of repeats of the repeating unit (3) relative to the total of the number of repeats of the repeating unit (1) and the number of repeats of the repeating unit (3) is greater than 0% and less than 20%. The hole transport material has one nitrogen atom.

A single-layer photosensitive layer included in an electrophotographic photosensitive member contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4).

##STR00001##

The percentage of the number of repeats of the repeating unit represented by formula (3) relative to a total of the number of repeats of the repeating unit represented by formula (1) and the number of repeats of the repeating unit represented by formula (3) is greater than 0% and less than 20%.

An electrophotographic photosensitive member includes a conductive substrate and an at-least-one-layer photosensitive layer including a specific photosensitive layer. The specific photosensitive layer contains a charge generating material, a binder resin, an electron transport material, and a hole transport material. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units (1), (2), (3), and (4).

##STR00001##

A percentage of the number of repeats of the repeating unit (3) relative to a total number of repeats of the repeating units (1) and (3) is greater than 0% and less than 50%. A percentage of the number of repeats of the repeating unit (4) relative to a total number of repeats of the repeating units (2) and (4) is at least 35% and less than 70%. The electron transport material includes a compound represented by formula (11), (12), (13), (14), (15), (16), or (17):

##STR00002##

In a positively charging single layer type electrophotographic photoreceptor having an over coat layer, an electrophotographic photoreceptor that is excellent in mechanical strength, electric characteristics, and adhesiveness, an electrophotographic photoreceptor cartridge, and an image formation device are provided. In a positively charging electrophotographic photoreceptor having a single layer type photosensitive layer and an over coat layer, the Martens hardness on the photoreceptor surface satisfies the prescribed condition, and preferably the photosensitive layer satisfies the particular relational expression of the contents and the molecular weights of the hole transporting substance and the electron transporting substance contained therein, thereby solving the problem.

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 a charge transport material, and in a case where a weight-average molecular weight Mw of the polyester resin (1) contained in the charge transport layer is defined as A (10,000), a value of a ratio M1/M2 of a mass M1 of the charge transport material contained in the charge transport layer to a mass M2 of the charge transport layer is defined as Cs, and an average thickness of the charge transport layer is defined as Ds (μm), expressions of 5≤A≤40, 0.28≤Cs≤0.55, 27≤Ds≤50, and 2.5≤(A×Ds)/(Cs×100)≤70.0 are satisfied.

##STR00001##

In Formula (A), n.sup.1 represents 1, 2, or 3, n.sup.1 number of m.sup.1's each independently represent 0, 1, 2, 3, or 4, m.sup.1 number 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.

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 charge transport material and a polyester resin, and a mass proportion of a chemical substance (AA) represented by Formula (AA) in a total mass of the charge transport layer is 2,000 ppm or less.

##STR00001##

In Formula (AA), X represents an organic group, and m.sup.AA represents an integer.

An electrophotographic photosensitive member includes a surface layer containing a charge transporting material and a specific polyester resin having a structure including a specific branched chain.