An electrophotographic photosensitive member with suppressed potential variation even in the case that a protective layer including a cured material of a composition having a polymerizable functional group is used is provided. An electrophotographic photosensitive member including a support, a charge generation layer, a charge transport layer containing a charge transporting material, and a protective layer, in the order presented, wherein the charge transport layer contains a polycarbonate resin having a structure selected from a group A and a structure selected from a group B, and the protective layer includes a cured material of a composition containing a compound having at least a functional group selected from chain-polymerizable functional groups and sequential polymerizable functional groups.

An electrophotographic photoreceptor comprising at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer is a laminate having a charge transport layer and a charge generation layer, the charge transport layer contains four or more types of compounds each having a maximum absorption wavelength falling within a wavelength range of from 300 nm to 600 nm in a tetrahydrofuran solution at 25? C., and maximum absorption wavelengths falling within the wavelength range of at least four types of the compounds of said four or more types of the compounds are separated from each other by 10 nm or more.

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 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.

Provided is an electrophotographic photosensitive member in which streaky image damage can be suppressed throughout long-term use in a low-temperature and low-humidity environment. An electrophotographic photosensitive member having a surface layer comprising a polyarylate and a polycarbonate, wherein the polyarylate has at least one structural unit selected from the group consisting of a structural unit represented by the following formula (1-1), a structural unit represented by the following formula (1-2) and a structural unit represented by the following formula (1-3), and the polycarbonate has a structural unit represented by the following formula (2-1).

##STR00001##

Provided is a process cartridge integrally supporting an electrophotographic photosensitive member, a developing unit, and a cleaning unit, and being detachably attachable onto a main body of an electrophotographic apparatus. A surface layer of the electrophotographic photosensitive member comprises a polycarbonate resin having a structural unit represented by the formula (1), a structural unit represented by the formula (2), and a structural unit represented by the formula (3). Toner contains: a toner particle containing a resin; and an external additive. The external additive contains a particle of a silicon atom-containing compound, and a content ratio of the particle of the silicon atom-containing compound in the toner is 2.0 to 3.0 mass % with respect to a total mass of the toner. Also provided is an electrophotographic apparatus including the process cartridge.

Provided is a positively charged electrophotographic photoconductor that provides a stable high-quality image in any environment, 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 on the electroconductive support and including a charge generation material, a hole transport material, an electron transport material and a 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 binder resin. In either embodiment, the binder resin contains a polycarbonate-based resin and has a water vapor permeability ranging from 5 to 13 g/m.sup.2.Math.day.

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.

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 ().

An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer, wherein an outermost layer contains a compound having a structure represented by general formula (I) below: ##STR00001## where R.sub.1 and R.sub.2 each independently represent a C.sub.1-12 alkyl group or a C.sub.5-12 cycloalkyl group; R.sub.3 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted C.sub.1-6 alkyl group, a substituted or unsubstituted C.sub.1-6 alkoxyl group, a C.sub.6-20 aryl group or a heterocycle group; X and Z each represent a single bond or a C.sub.1-6 alkylene group which may be substituted; and Y represents a OCO group or COO group. A method for manufacturing the photoreceptor and an electrophotographic device including the photoreceptor are additionally provided. The electrophotographic photoreceptor provides sufficient stain resistance and is less affected by temperature and humidity environments while maintaining various advantageous characteristics of photoreceptors.