There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including an electrophotographic photosensitive member and a charging member, wherein an outer surface of the charging member is composed of at least a matrix and at least a part of domains, a volume resistivity of the matrix is 1.010.sup.5 times or more of a volume resistivity of the domain, an average value Sd of circle equivalent diameters of the domains observed on the outer surface of the charging member is in a predetermined range, the electrophotographic photosensitive member contains a support, a photosensitive layer, and a protective layer in this order and when a surface roughness of the protective layer is measured, each of a protruding valley portion Rvk, a load length ratio Mr2, and Sd/Rvk is in a predetermined range.

Provided is an electrophotographic photosensitive member including a surface layer containing: a copolymerization product of a composition containing a hole-transportable compound having a chain-polymerizable functional group and a compound having a specific structure; and metal oxide particles.

An electrophotographic photosensitive member includes a support, an undercoat layer, a photosensitive layer, and a surface layer, the undercoat layer containing a binder resin and strontium titanate particles, the surface layer being a cured film of a composition containing at least one compound selected from a guanamine compound and a melamine compound, and a charge transport material having at least one substituent selected from OH, OCH.sub.3, NH.sub.2, SH, and COOH.

Provided is an electrophotographic photosensitive member improved both in wear resistance and in image unevenness. The electrophotographic photosensitive member includes a support, and a photosensitive layer and a surface layer on the support, wherein the surface layer is a cured product of a composition containing a compound represented by the formula (A) and a charge-transporting substance having at least one reactive functional group selected from the group consisting of a hydroxy group, a methoxy group, an amino group, a thiol group, and a carboxyl group.

An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin.

[00001]$\begin{array}{cc}0.60\frac{V}{\left(Q/S\right)\left(d/{\mathrm{.Math.}}_r.Math.{\mathrm{.Math.}}_0\right)}& \left(1\right)\end{array}$

In formula (1), Q represents a charge amount [C] of the circumferential surface of the image bearing member, S represents a charge area [m.sup.2] of the charged circumferential surface of the image bearing member, d represents a film thickness [m] of the photosensitive layer, co represents vacuum permittivity [F/m], and V represents a value calculated in accordance with formula V=V.sub.0V.sub.r.

Provided is an electrophotographic photosensitive member including a support and a surface layer, wherein the surface layer contains a copolymer of a composition containing a specific hole transporting compound and a specific compound.

An image forming apparatus including developing unit to develop electrostatic latent image with toner to form visible image, and cleaning unit including elastic member including surface layer and configured to remove the toner, wherein Martens hardness A and Martens hardness B of the surface layer measured by applying load of 1 N and load of 1,000 N, respectively, to position of the surface layer in thickness direction thereof using nanoindenter are both 2.5 N/mm.sup.2 or greater but 32.5 N/mm.sup.2 or less, and Martens hardness A and Martens hardness B satisfy inequality,
Martens hardness A>Martens hardness B
wherein coefficient of dynamic friction of the surface layer against polycarbonate is 0.5 or less, and the toner includes polyester resin insoluble to THF and Tg of THF-insoluble component of the toner determined from DSC curve of first heating of DSC is 60 C. or higher but 20 C. or lower.

An image forming apparatus including developing unit to develop electrostatic latent image with toner to form visible image, and cleaning unit including elastic member including surface layer and configured to remove the toner, wherein Martens hardness A and Martens hardness B of the surface layer measured by applying load of 1 N and load of 1,000 N, respectively, to position of the surface layer in thickness direction thereof using nanoindenter are both 2.5 N/mm.sup.2 or greater but 32.5 N/mm.sup.2 or less, and Martens hardness A and Martens hardness B satisfy inequality,

Martens hardness A>Martens hardness B

wherein coefficient of dynamic friction of the surface layer against polycarbonate is 0.5 or less, and the toner includes polyester resin insoluble to THF and Tg of THF-insoluble component of the toner determined from DSC curve of first heating of DSC is 60 C. or higher but 20 C. or lower.

Provided are an electrophotographic apparatus and a process cartridge each capable of suppressing the occurrence of a black spot (white background contamination) in an output image under a low-temperature and low-humidity environment. The electrophotographic apparatus includes: an electrophotographic photosensitive member including a support, a photosensitive layer, and a protective layer in the stated order; an exposing device; a developing device; and a cleaning device, wherein the protective layer has a triarylamine structure and a specific structure at a ratio in a specific range, and a toner contains toner particles each containing at least a resin, and an external additive. The toner has a volume-average particle diameter of 7 m or more. The external additive contains a compound containing a titanium atom. The ratio of the mass of the compound containing a titanium atom to the total mass of the toner is 0.6 mass % or more.

The electrophotographic photosensitive member includes: a support; a charge-generating layer; and a charge-transporting layer, the charge-generating layer and the charge-transporting layer being arranged on the support, wherein a surface layer of the electrophotographic photosensitive member contains: inorganic particles having an average particle diameter (L) of primary particles of 5 nm or more and 50 nm or less; and resin particles having an average particle diameter (L) of primary particles of 0.1 m or more and 5.0 m or less, and wherein in any cross-section of the surface layer, (Sm)/(S)0.3 is satisfied, where a region within (L/2) from a surface of each of the resin particles is defined as a region (M), a sum of cross-sectional areas of the inorganic particles in the any cross-section is represented by (S), and a sum of cross-sectional areas of the inorganic particles that are included in the region (M) is represented by (Sm).