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.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer of a single layer. The photosensitive layer contains a charge generating material, a binder resin, a hole transport material, and an electron transport material. The binder resin includes a polyester resin and a polycarbonate resin. The polyester resin includes a first repeating unit represented by general formula (1) shown below and a second repeating unit represented by general formula (2) shown below. The polycarbonate resin includes a third repeating unit represented by general formula (3) shown below and a fourth repeating unit represented by general formula (24) shown below. ##STR00001##
A content percentage of the polyester resin in the photosensitive layer is at least 0.3% by mass and no greater than 7.0% by mass.

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, at least one of a polyester resin that has a constitutional unit having an aromatic ring or a polycarbonate resin that has a constitutional unit having an aromatic ring, and a compound (1) represented by Formula (1) and having a melting point of 40° C. or higher,

##STR00001## in Formula (1), Ar represents an aromatic ring that may have a substituent, L represents a single bond, an oxygen atom, or a sulfur atom, R represents an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 20 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and n represents an integer of 1 or greater.

An image forming unit includes a photoreceptor and a charging member that comes into contact with a surface of the photoreceptor and charges the photoreceptor, in which the 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, the charge transport layer contains at least one of a polyester resin that has a constitutional unit having an aromatic ring or a polycarbonate resin that has a constitutional unit having an aromatic ring, the charging member includes a support member and an elastic layer disposed on the support member, and the elastic layer has a storage elastic modulus G′ of 5.0 MPa or less at a frequency of 100 Hz in dynamic viscoelasticity measurement under a temperature condition of 24° C.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer and contains a charge generating material, a hole transport material, an electron transport material, and a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), and (3).

##STR00001##

A ratio n.sub.1/n.sub.2 of the number n.sub.1 of repeats of the repeating unit represented by formula (1) to the number n.sub.2 of repeats of the repeating unit represented by formula (2) is at least 1.0.

An object of the present invention is to provide an electrophotographic photoreceptor which can prevent an increase in potential even using a fluorine resin in a charge transport layer, and can achieve both electrical properties and abrasion resistance, and present invention relates to a lamination type electrophotographic photoreceptor, in which a charge transport layer of the lamination type electrophotographic photoreceptor contains a compound having an E_homo of −4.550 eV or more based on structure optimization calculation by density functional calculation B3LYP/6-31G (d, p) and fluorine resin particles, and a content of the fluorine resin particles is 3% by weight to 20% by weight based on a total mass of the charge transport layer.

The present invention relates to an electrophotographic photoreceptor including a conductive support and a photosensitive layer on the conductive support, and the photosensitive layer contains a polymer A containing a repeating structural unit represented by a specific formula, and a polymer B containing a repeating structural unit represented by a specific formula. In addition, the present invention relates to an electrophotographic photoreceptor cartridge and an image forming apparatus including the electrophotographic photoreceptor.

The present invention provides an electrophotographic photoreceptor including at least a laminated photoreceptive layer in which a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance are laminated in this order on a substrate, where the charge generating substance is a titanyl phthalocyanine showing diffraction peaks at least at Bragg angles (2θ±0.2°) 7.3°, 9.4°, 11.6°, 24.2° and 27.3° in an X-ray diffraction spectrum using CuKα ray, and the laminated photoreceptive layer includes an optical absorption spectrum that has a maximum absorption at 800 to 850 nm and where a ratio Abs.sub.860 nm/Abs.sub.780 nm of a peak intensity at 860 nm (Abs.sub.860 nm) to a peak intensity at 780 nm (Abs.sub.780 nm) is 0.6 or more to 1.2 or less when a minimum absorbance at 400 to 800 nm is calibrated to 0.

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 this order, in which the charge transport layer contains at least one resin selected from a polyester resin or a polycarbonate resin, and in a case where a Martens hardness and an indentation hardness, which are acquired by an indentation test performed on the charge transport layer to a depth of 0.5 μm, are respectively defined as HM (N/mm.sup.2) and nIT (N/mm.sup.2), Relational Equation (0) is satisfied, an elastic deformation modulus is 45% or greater and 70% or less, and a tensile elastic modulus of the charge transport layer is 2,300 MPa or greater and 5,000 MPa or less,

nIT=a×HM−b(a=2±0.2,b=100±20).  (0)

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 having a structure represented by Formula (1) at a terminal and a charge transport material, and in a case where a weight-average molecular weight Mw of the polyester resin is defined as A (×10,000), a value of a ratio M1/M2 of a mass M1 of the charge transport material to a mass M2 of an entire charge transport layer is defined as Cs, and an average thickness of the charge transport layer is defined as Ds (μm), expressions of 7≤A≤40, 0.28≤Cs≤0.55, 27≤Ds≤50, and 5.0≤(A×Ds)/(Cs×100)≤70 are satisfied,

##STR00001## in Formula (1), nd represents an integer of 0 or greater and 4 or less, nd number of Rd's each independently represent a hydrocarbon group having 1 or more and 4 or less carbon atoms, L represents an ether bond or a —O—C(═O)— group, and * represent a bonding portion.