Electrophotographic photosensitive member

A process cartridge integrally supporting an electrophotographic photosensitive member having drum shape and at least one member selected from the group consisting of a charging unit, a developing unit and a cleaning unit, and being detachably attachable to a main body of an electrophotographic apparatus, the electrophotographic photosensitive member comprising:

• a support;
• and
• a photosensitive layer, an outer surface of the electrophotographic photosensitive member having wrinkles, wherein
• when an observation region having square form with one side of 100 μm is placed at any position on the outer surface, and a line that passes through a central point of the observation region and is parallel to a circumferential direction of the electrophotographic photosensitive member is defined as a first reference line L1, and 3,599 reference lines obtained by rotating the first reference line L1 at every 0.1° around the central point are respectively defined as L2 to L3,600,
• (i) each of L1 to L3,600 intersects with convex portions of the wrinkles at a plurality of locations and has at least two different intersection angles selected from the plurality of locations,
• (ii) when a two-dimensional power spectrum F(r,θ) with a frequency component as r and an angle component as θ is obtained by performing frequency analysis of height information of the wrinkles in the observation region, a one-dimensional radial direction distribution function p(r) obtained by integrating the two-dimensional power spectrum F(r,θ) in a θ direction has at least one maximum value, and
• (iii) when an angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at a frequency rp at which the one-dimensional radial direction distribution function p(r) has the maximum value, a variation in power values in the entire θ range is 10% or less.

An electrophotographic apparatus, comprising:

• an electrophotographic photosensitive member having drum shape, a charging unit, an exposing unit, a developing unit and a transfer unit;
• and
• the electrophotographic photosensitive member comprising a support and a photosensitive layer, an outer surface of the electrophotographic photosensitive member having wrinkles, wherein
• when an observation region having square form with one side of 100 μm is placed at any position on the outer surface, and a line that passes through a central point of the observation region and is parallel to a circumferential direction of the electrophotographic photosensitive member is defined as a first reference line L1, and 3,599 reference lines obtained by rotating the first reference line L1 at every 0.1° around the central point are respectively defined as L2 to L3,600,
• (i) each of L1 to L3,600 intersects with convex portions of the wrinkles at a plurality of locations and has at least two different intersection angles selected from the plurality of locations,
• (ii) when a two-dimensional power spectrum F(r,θ) with a frequency component as r and an angle component as θ is obtained by performing frequency analysis of height information of the wrinkles in the observation region, a one-dimensional radial direction distribution function p(r) obtained by integrating the two-dimensional power spectrum F(r,θ) in a θ direction has at least one maximum value, and
• (iii) when an angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at a frequency rp at which the one-dimensional radial direction distribution function p(r) has the maximum value, a variation in power values in the entire θ range is 10% or less.