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: In order to provide a photoelectric conversion element having higher photoelectric conversion efficiency, in a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing an organic-inorganic perovskite compound and disposed between the first electrode and the second electrode, a particle layer including particles that mainly contain a phthalocyanine compound is arranged between the photoelectric conversion layer and the first electrode.

Abstract: The electrophotographic photosensitive member includes a surface layer containing a binder resin, electroconductive particles, and insulating particles, wherein when a volume resistivity of the insulating particles is represented by R1 [?·cm], a volume resistivity of the electroconductive particles is represented by R2 [?·cm], a ratio of an area of the insulating particles that are exposed to a total area of the surface layer is represented by S1 [%], a ratio of an area of the electroconductive particles that are exposed to the total area of the surface layer is represented by S2 [%], an average exposed height of the insulating particles exposed to a surface of the electrophotographic photosensitive member is represented by L1 [nm], and an average exposed height of the electroconductive particles exposed to the surface of the electrophotographic photosensitive member is represented by L2 [nm], those parameters satisfy specific relational formulae.

Abstract: An electrophotographic photosensitive member including a surface layer containing a binder resin and metal oxide particles. An average primary particle diameter of the metal oxide particles measured from a cross-section of the surface layer is 20 to 70 nm. A content ratio of the metal oxide particles in the surface layer measured from the cross-section of the surface layer is 30 to 75 vol % with respect to a total volume of the surface layer.

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: There is provided an electrophotographic photosensitive member comprising: a support, a photosensitive layer, and a surface layer in this order, wherein an outer surface of the electrophotographic photosensitive member exhibits a wrinkled shape by having a concavo-convex shape, the surface layer comprises a binder resin and an inorganic particle, and at least a part of the inorganic particle exposes at a concave portion of the concavo-convex shape.

Abstract: Provided is an electrophotographic photosensitive member including an electroconductive support, a photosensitive layer, and a protection layer, wherein the protection layer comprises an electroconductive particle, the electroconductive particle has a surface comprising a metal oxide containing a titanium atom and a niobium atom, an atomic concentration ratio of the niobium atom to the titanium atom in the metal oxide is 0.01 to 0.20, the electroconductive particle is surface-treated with a compound having a silicon atom, a content ratio of the electroconductive particle in the protection layer is 5 vol % or more and less than 40 vol % with respect to a total volume of the protection layer, and relative concentrations of a plurality of atoms at a surface of the protection layer, which are determined by X-ray photoelectron spectroscopy, satisfy specific conditions.

Abstract: Provided is an electrophotographic photosensitive member having a feature in that, in a graph that is obtained by a method of measuring an EV curve, and that has a horizontal axis representing I and a vertical axis representing V, when V at I=0.500 [?J/cm2] is represented by Vr [V], a maximum value of S [V·?J/cm2] represented by S=I·(V?Vr) in a range of I=0.000 to 0.030 [?J/cm2] is represented by Smax [V·?J/cm2], and a product of a light amount Ii [?J/cm2] on the horizontal axis and a potential Vi[V] on the vertical axis at a point of intersection between an approximate straight line in a range of I=0.000 to 0.010 [?J/cm2] and an approximate straight line in a range of I=0.490 to 0.500 [?J/cm2] is represented by Si=Ii·(Vi?Vr) [V·?J/cm2], a ratio of Si to Smax, which is represented by AR=Si/Smax, satisfies AR?0.10.

Abstract: The present disclosure provides a photoelectric conversion element including a first electrode 3, a second electrode 7, a photoelectric conversion layer 5 between the first electrode 3 and the second electrode 7, and a reflection layer 6 between one of the first electrode 3 and the second electrode 7 and the photoelectric conversion layer 5. The wavelength at which the reflectance of the reflection layer 6 is maximum in the visible region is within the range of wavelengths in which the optical absorption coefficient of the photoelectric conversion layer 5 is ? or more of the maximum optical absorption coefficient in the visible region.

Abstract: Provided is an electrophotographic photosensitive member that includes a support, a charge generation layer on the support, and a charge transfer layer on the charge generation layer and that satisfies specifications on an EV curve based on a measurement method of NESA-EV curve. The electrophotographic photosensitive member can exhibit high character quality and a digital gradation characteristic in a low-line-number halftone while maintaining an analog gradation characteristic in a high-speed process.

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: The process cartridge includes an electrophotographic photosensitive member having a first support and a photosensitive layer; and a charging member. In the photosensitive member when an electric current is measured which flows when a voltage is applied to a surface while being varied, a gradient a1 of a low electric field region and a gradient a2 of a high electric field region satisfy a2/a1?1.50, in a graph. The charging member includes a second support having an electroconductive outer surface, and a second electroconductive layer including a matrix and a plurality of domains being dispersed in the matrix, at least a portion of the domain is exposed to an outer surface which includes at least the matrix and at least a portion of the domain, and a volume resistivity ?M of the matrix is 1.00×105 times or higher of a volume resistivity ?D of the domain.

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: The present disclosure provides an electrophotographic photosensitive member that can simultaneously achieve the suppression of the occurrence of the black spot in a charged portion and the suppression of the deterioration in sensitivity of an exposed portion, even after stored in a high-temperature and high-humidity environment. An electrophotographic photosensitive member includes an electro-conductive support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein an atomic concentration ratio R of the oxygen atom to the aluminum atom on the surface of the electro-conductive support, as measured by energy dispersive X-ray spectroscopy, satisfies the following Expression (1): 1.6?R??(1) and the undercoat layer includes a titanium oxide particle that is surface-treated with a particular silane compound.

Abstract: 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, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity ?M of the matrix is at least 1.00×105 times a volume resistivity ?D of the domain, and a specific calculated length SCP [?m] and a specific value relating a distance between the domains Dms [?m] satisfy SCP?3×Dms.

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: Provided is a process cartridge in which lateral running is suppressed while satisfactory potential fluctuation is maintained. The process cartridge includes: an electrophotographic photosensitive member including a support, a lowermost layer, and a photosensitive layer; and a charging member including a support and a conductive layer. In a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the lowermost layer while changing the AC voltage, is represented by fOPC (Hz), and in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the charging member while changing the AC voltage, is represented by fC (Hz), the fOPC and the fC each have a value within a certain range.