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.

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.

The electrophotographic photosensitive member includes an undercoat layer and a surface layer on or above a support in this order, in which the undercoat layer contains metal oxide particles and a specific binder resin, the surface layer contains a charge transporting substance, fluororesin particles, and a specific binder resin, an arithmetic average roughness Ra of a surface of the undercoat layer is 0.15 m or less, a refractive index (a) of the metal oxide particles and a refractive index (b) of the binder resin contained in the undercoat layer satisfy a specific relationship, and a refractive index (c) of the binder resin contained in the surface layer and a refractive index (d) of the fluororesin particles satisfy a specific relationship.

Provided are a process cartridge and an electrophotographic apparatus each suppressed in fluctuation in charging potential at the time of its long-term use. The process cartridge includes: an electrophotographic photosensitive member having a surface layer containing a resin and a charge-transporting substance; and a charging member configured to charge the electrophotographic photosensitive member, wherein an average of Martens hardnesses of the surface layer of the electrophotographic photosensitive member measured at a pushing force of 7 mN is 245 N/mm.sup.2 or more, and wherein in a core defined by three-dimensional surface texture standards (ISO 25178-2:2012) of the surface of the charging member, an average of Martens hardnesses measured at a pushing force of 0.04 mN is 2 N/mm.sup.2 or more and 20 N/mm.sup.2 or less, and an average of adhesivenesses measured with a scanning probe microscope in a field of view of 2-micrometer square is 70 mV or less.

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 (PEz) or a polycarbonate resin (PCz) that has at least one of a structure (Z1) represented by Formula (Z1) or a structure (Z2) represented by Formula (Z2) at at least one terminal, and a resin (X) that has at least one of a unit (X1) represented by Formula (X1) or a unit (X2) represented by Formula (X2), a mass proportion of the resin (X) in a total amount of the polyester resin (PEz), the polycarbonate resin (PCz), and the resin (X) in the charge transport layer is 0.5% by mass or greater and 30% by mass or less, and the charge transport layer has an average thickness of greater than 30 ?m and less than 50 ?m,

##STR00001## in Formula (Z1), Ar.sup.1 represents an aromatic ring that may have a substituent, in Formula (Z2), Ar.sup.2 represents an aromatic ring that may have a substituent,

##STR00002## in Formula (X1), R.sup.101, R.sup.102, and R.sup.103 each independently represent a hydrogen atom or an alkyl group having 1 or more and 5 or less carbon atoms, L.sup.101 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, an aromatic ring that may have a substituent, or a combination thereof, L.sup.102 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, or a combination thereof, R.sup.104 and R.sup.105 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms, n represents an integer of 0 or greater and 300 or less, R.sup.106, R.sup.107, and R.sup.108 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms or O[Si(R.sup.109)(R.sup.110)O].sub.mSi(R.sup.111)(R.sup.112)(R.sup.113), R.sup.109, R.sup.110, R.sup.111, R.sup.12, and R.sup.113 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms, and m represents an integer of 0 or greater and 20 or less, in Formula (X2), R.sup.201, R.sup.202, and R.sup.203 each independently represent a hydrogen atom or an alkyl group having 1 or more and 5 or less carbon atoms, L.sup.201 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, an aromatic ring that may have a substituent, or a combination thereof, L.sup.202 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, or a combination ther

A method for producing an electrophotographic photoreceptor having a conductive substrate, and a photosensitive layer formed on the conductive substrate. The method includes the steps of preparing a coating liquid containing a charge generating material, and applying the coating liquid on to the conductive substrate, to thereby form the photosensitive layer. An absolute value of a zeta potential of the charge generating material is 5 mV or more, and a half-value width of a zeta potential distribution of the charge generating material is 100 mV or less.

A process cartridge configured to be detachably attachable to a main body of an electrophotographic image forming apparatus, in which an occurrence of an image failure is suppressed, wherein the process cartridge includes an electrophotographic photosensitive member and a cleaning member arranged in contact with the electrophotographic photosensitive member, wherein an elastic deformation modulus of a surface layer of the electrophotographic photosensitive member is 35% or larger, and the cleaning member is formed of a urethane foam, wherein a density of the urethane foam is 200 to 500 kg/cm.sup.3, and a 25% compressive load of the urethane foam is 0.3 MPa or smaller.

Provided is a positively charged electrophotographic photoconductor, a manufacturing method thereof, and an electrophotographic apparatus using the same. The positively charged electrophotographic photoconductor includes an electroconductive support and a single layer-type photosensitive layer provided thereon including a charge generation material, a hole transport material, an electron transport material, and a mixed binder resin. Alternately, the positively charged electrophotographic photoconductor includes an electroconductive support; a charge transport layer provided on the electroconductive support and containing at least a hole transport material, and a binder resin; and a charge generation layer provided on the charge transport layer and including at least a charge generation material, a hole transport material, an electron transport material, and a mixed binder resin. In either embodiment, the mixed binder resin contains at least two resins including a polycarbonate-based resin selected to provide the mixed binder resin with a water vapor permeability ranging from 5 to 13 g/m.sup.2.Math.day.

Provided is an electrophotographic photosensitive member, including: a support; a charge-generating layer on the support; a charge-transporting layer on the charge-generating layer; and a protective layer on the charge-transporting layer, wherein the protective layer contains the following components (), (), and (): () a polymer of a hole-transportable compound; () a polycarbonate resin; and () a hole-transportable compound, wherein a content of the component () in the protective layer is 0.01 mass % or more and 4.0 mass % or less with respect to a content of the component () in the protective layer, wherein a content of the component () in the protective layer is 0.001 mass % or more and 3.0 mass % or less with respect to the content of the component () in the protective layer, and wherein the charge-transporting layer contains the component ().

Provided is a toner containing: a toner particle containing a binder resin; and an inorganic particle, wherein the inorganic particle contains a silicon oxide particle with a number-average particle diameter (D1) from 50 nm to 300 nm and a strontium titanate particle with a number-average particle diameter (D1) from 10 nm to 60 nm, the content of the silicon oxide particle is from 0.5 to 15.0 mass parts per 100 mass parts of the toner particle, the content of the strontium titanate particle is from 0.02 to 5.00 times the content of the silicon oxide particle, and in dielectric constant measurement at 25 C. and 1 MHz, the dielectric constant of the silicon oxide particle is from 1.0 pF/m to 20.0 pF/m, and the dielectric constant of the strontium titanate is from 25.0 pF/m to 100.0 pF/m.