There is provided an electrophotographic photosensitive member having a cylindrical shape, including a plurality of concave portions on a surface thereof, wherein a sum of opening areas of the concave portions is 5% or more and 65% or less based on a total area of a surface layer of the electrophotographic photosensitive member, an average value davg of depths of the concave portions satisfies the following Equation (1),
0.4davg3.0(m)Equation (1) a sum of opening areas of concave portions having a specific depth d is 95% or more of the sum of the opening areas of the concave portions, an average value Lavg of maximum widths of openings of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 m or more and 200 m or less, and the electrophotographic photosensitive member has at least one specific region B.

The present invention aims to provide an electrophotographic photoreceptor including a charge transport layer and being excellent in electrical properties and adhesiveness while exhibiting sufficient abrasion resistance indispensable for prolonging the life, and an electrophotographic photoreceptor cartridge and an image forming apparatus including the electrophotographic photoreceptor, which is an electrophotographic photoreceptor including a charge transport layer including at least two layers, wherein an elastic deformation ratio of a binder resin contained in a first charge transport layer which is an outermost layer and an elastic deformation ratio of a binder resin contained in a second charge transport layer satisfy a predetermined relationship.

Provided are a process cartridge and an electrophotographic apparatus each suppressed in fluctuation in charging potential at the time of its long-term use. The process cartridge includes: an electrophotographic photosensitive member having a surface layer containing a resin and a charge-transporting substance; and a charging member configured to charge the electrophotographic photosensitive member, wherein an average of Martens hardnesses of the surface layer of the electrophotographic photosensitive member measured at a pushing force of 7 mN is 245 N/mm.sup.2 or more, and wherein in a core defined by three-dimensional surface texture standards (ISO 25178-2:2012) of the surface of the charging member, an average of Martens hardnesses measured at a pushing force of 0.04 mN is 2 N/mm.sup.2 or more and 20 N/mm.sup.2 or less, and an average of adhesivenesses measured with a scanning probe microscope in a field of view of 2-micrometer square is 70 mV or less.

A photosensitive layer of an electrophotographic photosensitive member is a single layer and contains a charge generating material, a binder resin, an electron transport material, a hole transport material, and resin particles. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4).

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The repeating unit (3) has a percentage content of greater than 0% and less than 50% to the total number of repeats of the repeating units (1) and (3). The repeating unit (4) has a percentage content of at least 35% and less than 70% to the total number of repeats of the repeating units (2) and (4).

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin contains a polyarylate resin (1). The polyarylate resin is represented by general formula (1). The photosensitive layer has a scratch resistance depth of no greater than 0.50 m. The photosensitive layer has a Vickers hardness of at least 17.0 HV. ##STR00001##

There is provided an electrophotographic photosensitive member having a cylindrical shape, including a plurality of concave portions on a surface thereof, wherein a sum of opening areas of the concave portions is 5% or more and 65% or less based on a total area of a surface layer of the electrophotographic photosensitive member, an average value davg of depths of the concave portions satisfies the following Equation (1),

0.4davg3.0 (m)Equation (1) a sum of opening areas of concave portions having a specific depth d is 95% or more of the sum of the opening areas of the concave portions, an average value Lavg of maximum widths of openings of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 m or more and 200 m or less, and the electrophotographic photosensitive member has at least one specific region B.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The photosensitive layer has a scratch resistance depth of no greater than 0.50 m.

An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer containing at least a charge generating material, an electron transport material, a hole transport material, and a binder resin. The electron transport material includes a naphthoquinone derivative represented by general formula (1). An amount of triboelectric charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer (3) is at least +7 C/g. In general formula (1), R.sup.11 and R.sup.12 are respectively the same as R.sup.11 and R.sup.12 described in the description.

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The invention relates to an electrophotographic photoreceptor which is excellent in abrasion resistance and electrical properties by using a fluororesin and a polymer containing a structure represented by a specific formula, and has a long life span, an electrophotographic photoreceptor cartridge and an image forming apparatus including the electrophotographic photoreceptor, and a dispersant which is excellent in dispersibility of a fluororesin particle, and the electrical properties, and the compatibility with a binder resin.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer and contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin has a viscosity average molecular weight of at least 25,000 and no greater than 50,000. A strain at break of the photosensitive layer is at least 4.9% and no greater than 13.0%. A scratch resistant depth of the photosensitive layer is no greater than 0.50 m.