An electrophotographic photosensitive member, which is excellent in cleaning property and durability, and in which residual potential is reduced and occurrence of a crack is suppressed. In the electrophotographic photosensitive member including a surface layer, the surface layer contains: a binder resin; and organic resin particles, the binder resin has a specific structural unit, and the organic resin particles are each subjected to surface treatment with a specific compound.

An image forming apparatus includes a photosensitive member, first and second charging members, a developing member, a transfer member, first and second charging voltage applying portions, a transfer voltage applying portion, and a controller. The controller controls the transfer voltage applying portion so that a region of at least a part of the photosensitive member surface contacting the transfer member in a transfer position has a potential of an opposite polarity to the predetermined polarity, controls the first charging voltage applying portion so that the surface of the photosensitive member is charged in a first charging position by applying a first charging voltage of less than a discharge start voltage, and controls the second charging voltage applying portion so that the surface of the photosensitive member is charged in a second charging position by applying a second charging voltage of not less than the discharge start voltage.

An electrophotographic photosensitive member that can resist mass printing. The electrophotographic photosensitive member is an electrophotographic photosensitive member including a surface layer containing a binder resin and inorganic particles. The surface layer contains a urethane resin as the binder resin, wherein the value of the ratio of the volume of the inorganic particles to the volume of the binder resin in the surface layer is 0.10 or more and 3.0 or less. Protrusions derived from the inorganic particles are present on the surface of the surface layer. The inorganic particles to be incorporated into the surface layer have a number-based average primary particle diameter of 10 nm or more and 500 nm or less. The surface of the surface layer has a maximum height roughness Rz of 10 nm or more and 760 nm or less.

Provided is an electrophotographic apparatus including: an electrophotographic photosensitive member; a charging unit; an exposing unit; and a developing unit, wherein the electrophotographic photosensitive member includes a monolayer type photosensitive layer containing a charge generating material, a hole transporting material, an electron transporting material, and a first binder resin, wherein the photosensitive layer contains, as the first binder resin, a polyester resin having specific structural units, wherein the developing unit is a developing roller including a shaft body, an elastic layer arranged on an outer periphery of the shaft body, and a coating layer arranged on an outer periphery of the elastic layer, and wherein the coating layer contains a second binder resin and a silica particle.

A positively chargeable electrophotographic photoreceptor includes a single layer-type photosensitive layer that contains a hole transport material, an electron transport material, a charge generation material, and a binder resin, in which the binder resin contains a resin A having an elastic deformation rate of 53.0% or more and a resin B having an elastic deformation rate difference of 12% or more and 17% or less with respect to the resin A.

Provided is an electrophotographic apparatus in which the occurrence of image density unevenness (pattern memory) at the time of repeated use under a high-temperature and high-humidity environment is suppressed. The electrophotographic apparatus is an electrophotographic apparatus including: an electrophotographic photosensitive member; and a developing unit, which includes a toner, and which is configured to develop an electrostatic latent image with the toner to form a toner image on a surface of the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member includes a surface layer containing a compound represented by the formula (1), a binder resin, and silicone resin particles, and wherein the toner includes toner particles each containing a polyester resin having a polyethylene terephthalate segment.

An electrophotographic photoreceptor includes: a conductive substrate; and a multilayer-type photosensitive layer that is disposed on the conductive substrate and has a charge generation layer and a charge transport layer. The charge transport layer contains a charge-transporting material and a polyester resin (1) having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B). The polyester resin (1) contained in the charge transport layer satisfies 50,000Mw200,000 and 4.0<Mw/Mn<6.0, wherein Mw is a weight average molecular weight of the polyester resin (1), and Mn is a number average molecular weight of the polyester resin (1).

##STR00001##

In formula (A), Ar.sup.A1 and Ar.sup.A2 are each independently an optionally substituted aromatic ring, L.sup.A is a single bond or a divalent linking group, and n.sup.A1 is 0, 1, or 2. In formula (B), Ar.sup.B1 and Ar.sup.B2 are each independently an optionally substituted aromatic ring, L.sup.B is a single bond, an oxygen atom, a sulfur atom, or C(Rb.sup.1)(Rb.sup.2), and n.sup.B1 is 0, 1, or 2, and Rb.sup.1 and Rb.sup.2 are each independently a hydrogen atom, a C1-C20 alkyl group, a C6-C12 aryl group, or a C7-C20 aralkyl group, and Rb.sup.1 and Rb.sup.2 taken together may form a cyclic alkyl group.

An electrophotographic photoreceptor includes: a conductive substrate; and a photosensitive layer. The photosensitive layer includes a polyarylate resin, a hole transporting agent, and an antioxidant. The polyarylate resin has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2). The antioxidant is a compound represented by the following formula (AOX1).

##STR00001## In the formula (1), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a methyl group and t represents an integer of 1 or more and 3 or less.

##STR00002## In the formula (2), R.sup.3 represents a divalent group represented by the following formula (X1), (X2), or (X3).

##STR00003##

To provide an electrophotographic apparatus and a process cartridge each suppressing the occurrence of image smearing in an output image under a high-temperature and high-humidity environment, provided are the following electrophotographic apparatus and process cartridge. That is, provided are an electrophotographic apparatus including: an electrophotographic photosensitive member; a charging unit; an image exposing unit; a developing unit; and a transferring unit, wherein the electrophotographic photosensitive member includes a surface layer containing indium tin oxide particles and a (meth)acrylic resin, and wherein the toner contains strontium titanate particles as an external additive, and a process cartridge.

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer that is provided on the conductive substrate and contains zinc oxide particles and a binder resin, a charge generation layer that is provided on the undercoat layer and contains titanium-containing organic pigment and a binder resin, and a charge transport layer that is provided on the charge generation layer, in which a film thickness of the undercoat layer is 15.0 m or more and 30.0 m or less, in a case where the film thickness of the undercoat layer is 22.0 m or more and 30.0 m or less, each of a proportion of a Ti concentration and a proportion of a Zn concentration with respect to a total of the Ti concentration and the Zn concentration in a region within +500 nm in a film thickness direction from an interface between the undercoat layer and the charge generation layer is 30% or more and 70% or less, and in a case where the film thickness of the undercoat layer is 15.0 m or more and less than 22.0 m, each of a proportion of a Ti concentration and a proportion of a Zn concentration with respect to a total of the Ti concentration and the Zn concentration in a region within +500 nm in a film thickness direction from an interface between the undercoat layer and the charge generation layer is 20% or more and 80% or less.