An image forming unit includes a photoreceptor and a charging member that comes into contact with a surface of the photoreceptor and charges the photoreceptor, in which the 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, the charge transport layer contains at least one of a polyester resin that has a constitutional unit having an aromatic ring or a polycarbonate resin that has a constitutional unit having an aromatic ring, the charging member includes a support member and an elastic layer disposed on the support member, and the elastic layer has a storage elastic modulus G′ of 5.0 MPa or less at a frequency of 100 Hz in dynamic viscoelasticity measurement under a temperature condition of 24° C.

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer on the conductive substrate, and a photosensitive layer on the undercoat layer, in which the undercoat layer is formed of a cured product of a composition that contains a reactive group-containing triarylamine compound, a curing agent, and an electron transport material and that has a butyral resin content of 0 mass % or more and 5 mass % or less relative to all solid components in the undercoat layer.

An electrophotographic photoreceptor includes a conductive support, an undercoat layer on the conductive support, and a charge generation layer on the undercoat layer, in which the charge generation layer contains a phthalocyanine compound, the undercoat layer contains an electron transport compound, and a difference between an energy level of the lowest unoccupied molecular orbital of the phthalocyanine compound and an energy level of the lowest unoccupied molecular orbital of the electron transport compound is less than 0.45 eV.

The present disclosure provides an electrophotographic photosensitive member that can obtain a satisfactory image free from the image defect such as the interference fringes as an electrophotographic photosensitive member, and can achieve high fineness in an output image. The electrophotographic photosensitive member includes a support, an electroconductive layer and a photosensitive layer, in this order, wherein the electroconductive layer comprises a binder resin, a metal oxide particle and a silica particle, a content of the metal oxide particle in the electroconductive layer is 20.0 to 60.0% by volume with respect to total volume of the electroconductive layer, the metal oxide particle has an average primary particle diameter of 50 to 500 nm, and the silica particle has an average primary particle diameter of 10 to 300 nm.

An electrophotographic photosensitive member including a support, an intermediate layer, and a photosensitive layer in this order, wherein the intermediate layer comprises a tungsten oxide particle, and the tungsten oxide particle contains a tungsten atom, an oxygen atom, and a cesium atom.

An electrophotographic photosensitive member including a support, an intermediate layer, and a photosensitive layer in this order, wherein the intermediate layer comprises a tungsten oxide particle, and the tungsten oxide particle contains a tungsten atom, an oxygen atom, and a cesium atom.

An electrophotographic photoreceptor includes a conductive substrate, an undercoating layer, and a photosensitive layer. The undercoating layer that is provided on the conductive substrate and includes a binder resin and a charge transporting material. The binder resin includes a resin obtained by polymerizing a diallyl phthalate compound. The photosensitive layer that is provided on the undercoating layer.

An electrophotographic photoreceptor includes a conductive substrate, an undercoating layer that is disposed on the conductive substrate, and a photosensitive layer that is disposed on the undercoating layer, in which the undercoating layer contains at least one perinone compound selected from the group consisting of the compounds represented by Formulas (1) and (2), and at least one acceptor compound selected from the group consisting of compounds represented by Formula (3) to (15) which are shown in the specification. ##STR00001##

An electrophotographic photosensitive member including: a support, an undercoat layer formed above the support, a charge generation layer formed on the undercoat layer, and a charge transport layer formed above the charge generation layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide particle which is surface-treated with a compound represented by Formula (1): ##STR00001##
when a volume of the titanium oxide particles to a volume of the polyamide resin in the undercoat layer is a, and an average primary particle diameter of the titanium oxide particles is b [μm], the following Equation (A) is satisfied: Equation (A): 14.0≤a/b≤19.1; and the charge generation layer contains a charge generating material and a thermoplastic resin having a hydroxyl group and a hydroxyl number of 50 mgKOH/g or more.

An electrophotographic photoreceptor includes an electrically conductive substrate, and a laminate-type photosensitive layer formed on the electrically conductive substrate. An allowable range of a charging voltage Vx to be applied to the electrophotographic photoreceptor by a charging device is V.sub.0−150≤V.sub.x≤V.sub.0+150, and an electrostatic capacitance per unit area of the electrophotographic photoreceptor is 90 pF/cm.sup.2 or more. VO is an initial charging voltage applied to the electrophotographic photoreceptor. Also, an image forming apparatus and an image forming cartridge can be provided with the electrophotographic photoreceptor.