Provided is an electrophotographic photosensitive member including an electroconductive support, a photosensitive layer, and a protection layer, wherein the protection layer contains electroconductive particles, a content of the electroconductive particles in the protection layer is 40 to 70 vol %, and a volume resistivity of the protection layer is 1.0×10.sup.9 to 1.0×10.sup.14 Ω.Math.cm.

Provided is an image forming method using a toner for developing an electrostatic charge image and an electrophotographic photoreceptor, and containing at least a charging step, an exposing step, a developing step and a transferring step, wherein the electrophotographic photoreceptor has a photosensitive layer, and the photosensitive layer contains a triphenylamine derivative having a specific structure as a charge transport material, and the toner for developing an electrostatic charge image contains at least titanic acid compound particles as an external additive.

In an example, a photosensitive imaging surface is provided by an extended photodiode structure.

An image forming apparatus is provided that includes: an image bearer; a charger; an irradiator; a developing device containing a toner; and a transfer device. The image bearer has a Martens hardness of from 185 to 250 N/m.sup.2. The toner satisfies a relation 0.13≤X/Dn≤0.16, where X [μm] represents an average value of an amount of deformation of the toner by micro-indentation at when a load reaches 3.00×10.sup.−4 N at a loading rate of 3.0×10.sup.−5 N/sec under an environment of 32 degrees C. and 40% RH, and Dn [μm] represents a number average particle diameter of the toner. The toner contains an external additive comprising silica particles and particles composed mainly of strontium titanate. The particles composed mainly of strontium titanate further contain a third element M selected from the group consisting of La, Mg, Ca, Sn, and Si.

An electrophotographic photoreceptor includes: a conductive substrate; an undercoating layer that contains inorganic particles surface-treated with a surface treatment agent, and is provided in contact with an outer peripheral surface of the conductive substrate; and a photosensitive layer provided on the undercoating layer, wherein, with respect to the outer peripheral surface of the conductive substrate, a proportion of an area being in contact with the inorganic particles is from 82% to 91%.

Provided is an electrophotographic photosensitive member, which has high abrasion resistance and is resistant to being deeply flawed. Specifically, provided is an electrophotographic photosensitive member comprising a support and a surface layer formed on the support, wherein the surface layer comprises at least inorganic particles having pores in surfaces thereof, wherein at least a resin in the surface layer penetrates the pores, and wherein when vibration having a frequency of 0.5 Hz is applied to the surface layer at 28° C., the loss tangent tan δ of the dynamic viscoelasticity of the surface layer is from 0.005 to 0.05.

An electrophotographic photoconductor in which a surface layer of a photosensitive layer or an overcoat layer has a glass transition temperature Tg greater than 100° C. and a hardness greater than 0.22 GPa. An electrophotographic cartridge and an electrophotographic imaging apparatus include the electrophotographic photoconductor. Flipping-over of a cleaning blade that comes into contact with the electrophotographic photoconductor may be effectively suppressed or prevented, the degree of freedom in terms of cleaning blade selection may be increased, and the possibility of causing high-frequency noise due to friction may be reduced.

The electrophotographic photosensitive member includes: a support; a charge-generating layer; and a charge-transporting layer, the charge-generating layer and the charge-transporting layer being arranged on the support, wherein a surface layer of the electrophotographic photosensitive member contains: inorganic particles having an average particle diameter (Lα) of primary particles of 5 nm or more and 50 nm or less; and resin particles having an average particle diameter (Lβ) of primary particles of 0.1 μm or more and 5.0 μm or less, and wherein in any cross-section of the surface layer, “(Smα)/(Sα)≥0.3” is satisfied, where a region within (Lβ/2) from a surface of each of the resin particles is defined as a region (M), a sum of cross-sectional areas of the inorganic particles in the any cross-section is represented by (Sα), and a sum of cross-sectional areas of the inorganic particles that are included in the region (M) is represented by (Smα).

An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer on the conductive substrate. The outermost surface layer of the electrophotographic photoreceptor contains fluorine-containing resin particles, a fluorine graft polymer, and an acidic compound having an acid dissociation constant (pKa) of 3 or less in water at 25° C. The amount of the acidic compound relative to the outermost surface layer is 100 ppm or more and 10000 ppm or less.

A process cartridge which allows any spot and stripe as image defects to be suppressed is provided. A process cartridge, in which an electroconductive layer of a charging member has a matrix including a first rubber, and domains dispersed in the matrix, the domains include a second rubber and an electron electroconductive agent, at least some of the domains are exposed on a surface of the charging member, when a volume resistivity of the matrix is 10.sup.5 times or more a volume resistivity of the domains, a protective layer of an electrophotographic photosensitive member includes a metal oxide particle, and when a number average primary particle size of the metal oxide particle is defined as Sm and an average value of equivalent circle diameters of the domains is defined as Sd, the Sd/Sm satisfies the following expression (1): 0.5<Sd/Sm<100 . . . expression (1).