A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

An electrophotographic photoreceptor includes a conductive support and a single-layer photosensitive layer. The conductive support has an outer peripheral surface with a maximum surface roughness height (Rmax) of about 4.0 m or less, and the outer peripheral surface has a recess with a depth-to-aperture size ratio (depth/aperture size) of about 0.03 or more and about 0.12 or less. The single-layer photosensitive layer is disposed on the conductive support and has a thickness of about 20 m or more and a modulus of elasticity of about 4.5 GPa or more.

An electrophotographic photoreceptor includes a conductive support and a single-layer photosensitive layer. The conductive support has an outer peripheral surface with a maximum surface roughness height (Rmax) of about 4.0 m or less, and the outer peripheral surface has a recess with a depth-to-aperture size ratio (depth/aperture size) of about 0.03 or more and about 0.12 or less. The single-layer photosensitive layer is disposed on the conductive support and has a thickness of about 20 m or more and a modulus of elasticity of about 4.5 GPa or more.

Provided is an electrophotographic roller including a cylindrical base and an elastic layer on an outer peripheral surface of the base, the base having a joint extending from one end to the other end in a longitudinal direction thereof, at least a part of the joint has a gap penetrating the joint in a thickness direction of the base, and a part of a material for the elastic layer entering the gap and covering a portion of an inner peripheral surface of the base near the gap to form an anchor portion of the elastic layer.

Provided is an electrophotographic roller including a cylindrical base and an elastic layer on an outer peripheral surface of the base, the base having a joint extending from one end to the other end in a longitudinal direction thereof, at least a part of the joint has a gap penetrating the joint in a thickness direction of the base, and a part of a material for the elastic layer entering the gap and covering a portion of an inner peripheral surface of the base near the gap to form an anchor portion of the elastic layer.

A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2=32.200.20 ( represents a Bragg angle) in a CuK characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.

An electrophotographic photoreceptor according to the present invention includes a conductive support, a photosensitive layer, and a protective layer disposed in sequence. The protective layer includes a cured product of a composition containing a radically polymerizable compound, a charge transporting material exhibiting a maximal absorption wavelength of 40550 nm, and a photopolymerization initiator of a single-molecule system; and a following Expression (A) is satisfied:
G=Eox(D/D.sup.+)Ered(A.sup./A)E*0.2 [eV]Expression (A):
G represents a free energy change, Eox(D/D.sup.+) represents an oxidation potential of the charge transporting material, Ered(A.sup./A) represents a reduction potential of the photopolymerization initiator, and E* represents an excitation energy of the charge transporting material.