Abstract: Provided is an electrophotographic apparatus including: an electrophotographic photosensitive member; a voltage application unit configured to cause discharge from an electroconductive member to the electrophotographic photosensitive member; a charge transfer amount detection unit configured to detect a charge transfer amount per unit time resulting from the discharge from the electroconductive member to the electrophotographic photosensitive member; and a charging potential control unit, wherein V1 and V2 defined by specific procedures for the electrophotographic photosensitive member satisfy a relationship represented by the following expression (E-4): 100V1<V2?V1 (E-4), and wherein the charging potential control unit is configured to control the charging potential of the electrophotographic photosensitive member at the time of image formation.

Abstract: An electrophotographic photosensitive member that shows stable sensitivity even when repeatedly used. The electrophotographic photosensitive member is an electrophotographic photosensitive member including a support, an undercoat layer, a charge generating layer, and a charge transporting layer in the stated order, wherein the undercoat layer contains two kinds of electron transporting substances.

Abstract: An electrophotographic photosensitive member capable of suppressing a pattern memory. Specifically, an electrophotographic photosensitive member including: a support; an undercoat layer formed on the support; and a photosensitive layer formed on the undercoat layer, wherein the undercoat layer contains a polymerization product of a composition containing: an electron-transporting substance represented by the formula (1); and a crosslinking agent, and wherein the crosslinking agent has a functional group capable of being bonded to at least one polymerizable functional group of the electron-transporting substance.

Abstract: Provided is an electrophotographic apparatus including: an electrophotographic photosensitive member; a voltage application unit configured to cause discharge from an electroconductive member to the electrophotographic photosensitive member; a charge transfer amount detection unit configured to detect a charge transfer amount per unit time resulting from the discharge from the electroconductive member to the electrophotographic photosensitive member; and a charging potential control unit, wherein V1 and V2 defined by specific procedures for the electrophotographic photosensitive member satisfy a relationship represented by the following expression (E-4): 100V1<V2?V1 (E-4), and wherein the charging potential control unit is configured to control the charging potential of the electrophotographic photosensitive member at the time of image formation.

Abstract: An image forming apparatus including an electrophotographic photosensitive member having a support and a photosensitive layer, a charging unit that forms an electrostatic image on an outer surface of the electrophotographic photosensitive member, a developing unit that supplies a toner to the electrostatic image to form a toner image, and a transfer unit that transfers the toner image on a transfer medium. In this image forming apparatus, the surface layer of the electrophotographic photosensitive member contains a binder resin (A) having a specific structure and silica particles, and the wax contains a specific monoester compound.

Abstract: An electrophotographic photosensitive member has a charge generation layer having a film thickness of 0.2 ?m or larger and a charge transport layer on a support, wherein in a case where, at 23.5° C. and 50% RH, the photosensitive member is subjected to operations and measurement of: specific (1), (2), (3) and (4), an absolute value of a slope ? of a linear approximation straight line is 4×10?3 or smaller, in a range where the electric field strength E is 10 to 40 V/?m, which is expressed by a relational expression between a recombination constant Pe and an electric field strength E, which is obtained from a specific graph which has been obtained by repeatedly performing the specific operations and measurement of (1) to (4) while changing Iexp from 0.000 to 1.000 ?J/cm2 at intervals of 0.001 ?J/cm2.

Abstract: The electrophotographic apparatus includes: an electrophotographic photosensitive member; a charging unit; an image-exposing unit; a charge transfer amount-sensing unit for sensing the amount of charge transferred to the electrophotographic photosensitive member; and an exposed portion potential-controlling unit for controlling the potential of each of the exposed portions of the electrophotographic photosensitive member based on a sensing result, which is obtained by charging the electrophotographic photosensitive member with the charging unit, performing image exposure with the image-exposing unit in at least one light amount weaker than a light amount in which the normalized radius of curvature R of the electrophotographic photosensitive member represented by the following equation (E1), the normalized radius of curvature being obtained by a method of measuring an EV curve, shows a minimum, and in at least two light amounts stronger than the light amount in which the normalized radius of curvature shows th

Abstract: Provided is an electrophotographic apparatus which uses a light emitting diode array as an exposure unit and exposes a photosensitive member to a quantity of light from the LED array whose average light quantity satisfies 0.8×Emin or more and 1.1×Emin or less on condition that a normalized radius of curvature R of a normalized graph derived from the E-V curve of the photosensitive member has a minimum value of 0.24 or less, and a light quantity at the minimum value of the normalized radius of curvature R is Emin [?J/cm2]. This electrophotographic apparatus prevents both the occurrence of image unevenness due to light quantity variation among the elements of the LED array and the generation of ghost images due to a rest potential.

Abstract: An image forming apparatus comprising an electrophotographic photosensitive member and a developing device for supplying a toner onto the electrophotographic photosensitive member, the developing device having the toner, wherein the electrophotographic photosensitive member has a surface layer comprising a binder resin (A), the toner has a toner particle, the toner particle has a core comprising a binder resin (B) and a wax and a shell layer formed on a surface of the core, the binder resin (A) has a prescribed structure: the wax comprises a prescribed monoester compound: and a process cartridge.

Abstract: The electrophotographic photosensitive member has: a cylindrical support; a charge generating layer formed on the cylindrical support; and a charge transport layer formed on the charge generating layer, the charge generating layer contains a hydroxygallium phthalocyanine crystal having a particular CuK? characteristic X-ray diffraction peak, a titanyl phthalocyanine crystal having a particular CuK? characteristic X-ray diffraction peak or a chlorogallium phthalocyanine crystal having a particular spectral absorption spectrum as a charge generating material, and in the charge generating layer, with respect to the film thickness of the charge generating layer, when a region from the central position of an image forming area to the end position of the image forming area is divided in the axial direction of the cylindrical support into five equal regions and the average film thickness of the charge generating layer in each region satisfies a specific condition.

Abstract: Provided is an electrophotographic photosensitive member which enables a reduction in unevenness in distribution of the post-exposure potential of the photosensitive member and a reduction in unevenness in life of the photosensitive member in the axial direction. An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer, and a charge transport layer in this order, wherein when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in the axial direction of the cylindrical support is equally divided into five regions, average film thicknesses of the charge generating layer in the five regions satisfy specific relations in a film thickness of the charge generating layer and average film thicknesses of the charge transport layer in the five regions satisfy specific relations in a film thickness of the charge transport layer.

Abstract: An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer formed on the cylindrical support, and a charge transport layer formed on the charge generating layer, in which in the charge generating layer, when a region from a central position of an image forming region to an end position of the image forming region in an axis direction of the cylindrical support is divided equally into five regions, film thicknesses of the charge generating layers in each of the regions satisfy a specific relationship with each other, and in the charge transport layer, when a region from the central position of the image forming region to the end position of the image forming region in the axis direction of the cylindrical support is divided equally into five regions, film thicknesses of the charge transport layers in each of the regions satisfy a specific relationship with each other.

Abstract: Provided is an electrophotographic photosensitive member in which discharge streaks generated in an end portion can be suppressed. The electrophotographic photosensitive member includes a cylindrical support, a charge-generating layer, and a charge-transporting layer in the stated order. In the electrophotographic photosensitive member, when a region between a center position and a 90% position situated at a 90% of a length of from the center position to one end of the electrophotographic photosensitive member in an axial direction thereof from the center position, is defined as a region X, and a region between the 90% position and the end of the electrophotographic photosensitive member is defined as a region Z. Average thicknesses in regions obtained by equally dividing the region X into five and regions obtained by equally dividing the region Z into three satisfy particular relationships.

Abstract: An image forming apparatus comprising an electrophotographic photosensitive member and a developing device that has a toner and supplies the toner onto the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises a surface layer comprising a binder resin (A), the binder resin (A) comprises a specific structure, the toner comprises a toner particle, the toner particle comprises a binder resin (B) and a wax, and the wax comprises a prescribed diester compound; and a process cartridge and a cartridge set.

Abstract: An image forming apparatus comprising an electrophotographic photosensitive member and a developing device comprising a toner, the developing device being for supplying the toner to the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises a surface layer comprising a binder resin (A), the binder resin (A) comprises a specific structure, the toner comprises a toner particle, the toner particle comprises a binder resin (B) and a wax, and the wax has a value ?p(w) of a polarity term based on Hansen solubility parameters of 1.8 (J/cm3)0.5 to 2.5 (J/cm3)0.5, as well as a process cartridge, a cartridge set and an image forming method.

Abstract: An image forming apparatus comprising an electrophotographic photosensitive member and a developing device that has a toner and supplies the toner onto the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises a surface layer comprising a binder resin (A), the binder resin (A) comprises a specific structure, the toner comprises a toner particle, the toner particle comprises a binder resin (B) and a wax, and the wax comprises a prescribed diester compound; and a process cartridge and a cartridge set.

Abstract: An image forming apparatus in which no image smearing occurs even under high-temperature and high-humidity conditions while durability and low-temperature fixability are maintained. The image forming apparatus comprises: an electrophotographic photosensitive member comprising a support and a photosensitive layer formed on the support; an image forming unit configured to form an electrostatic image on the electrophotographic photosensitive member; a developing unit comprising a toner and configured to supply the toner to the electrostatic image formed on the electrophotographic photosensitive member for forming a toner image; and a transferring unit configured to transfer the toner image from the electrophotographic photosensitive member, wherein a surface layer of the electrophotographic photosensitive member is a surface layer comprises a binder resin (A), the toner is a toner including toner particles each containing a binder resin (B) and a wax, and the binder resin (A) has a specific structure I.

Abstract: An image forming apparatus comprising an electrophotographic photosensitive member and a developing device for supplying a toner onto the electrophotographic photosensitive member, the developing device having the toner, wherein the electrophotographic photosensitive member has a surface layer comprising a binder resin (A), the toner has a toner particle, the toner particle has a core comprising a binder resin (B) and a wax and a shell layer formed on a surface of the core, the binder resin (A) has a prescribed structure: the wax comprises a prescribed monoester compound: and a process cartridge.

Abstract: An image forming apparatus including an electrophotographic photosensitive member having a support and a photosensitive layer, a charging unit that forms an electrostatic image on an outer surface of the electrophotographic photosensitive member, a developing unit that supplies a toner to the electrostatic image to form a toner image, and a transfer unit that transfers the toner image on a transfer medium. In this image forming apparatus, the surface layer of the electrophotographic photosensitive member contains a binder resin (A) having a specific structure and silica particles, and the wax contains a specific monoester compound.

Abstract: Provided is an electrophotographic photosensitive member which enables a reduction in unevenness in distribution of the post-exposure potential of the photosensitive member and a reduction in unevenness in life of the photosensitive member in the axial direction. An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer, and a charge transport layer in this order, wherein when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in the axial direction of the cylindrical support is equally divided into five regions, average film thicknesses of the charge generating layer in the five regions satisfy specific relations in a film thickness of the charge generating layer and average film thicknesses of the charge transport layer in the five regions satisfy specific relations in a film thickness of the charge transport layer.