Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus
Provided is a cylindrical electrophotographic photosensitive member, including a concave/convex portion forming region in which at least one of concave portions and convex portions are formed on a surface of the electrophotographic photosensitive member from a central portion to both end portions in an axial direction of the electrophotographic photosensitive member, wherein a maximum value Lmax and a minimum value Lmin of a distance L from the central portion to one end portion of the concave/convex portion forming region in the axial direction of the surface of the electrophotographic photosensitive member satisfy a specific relation.
1. A cylindrical electrophotographic photosensitive member, comprising:
a concave/convex portion forming region in which at least one of concave portions and convex portions are formed on a surface of the electrophotographic photosensitive member from a central portion to both end portions in an axial direction of the electrophotographic photosensitive member, wherein
0.011≤( L max− L min)/ L max≤0.087 and 0.100≤( L max− L min)/ P≤ 0.333
where Lmax and Lmin are respectively maximum and minimum values of a distance L from the central portion to one end portion of the concave/convex portion forming region in the axial direction of the surface of the electrophotographic photosensitive member, and P is a diameter of the electrophotographic photosensitive member, and
a ratio of an area of the concave/convex portion forming region to an area of region A is 20 to 80% where region A is a region in an axial end portion of the surface of the electrophotographic photosensitive member that is sandwiched between a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmin is measured, and a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmax is measured.
2. The electrophotographic photosensitive member according to claim 1 , wherein the concave/convex portion forming region has Lmax and Lmin at each of the end portions in the axial direction of the electrophotographic photosensitive member.
3. A process cartridge that integrally supports a cylindrical electrophotographic photosensitive member and a cleaning unit having a cleaning blade disposed in contact with the electrophotographic photosensitive member, and which is detachably attachable to a main body of an electrophotographic apparatus, the electrophotographic photosensitive member comprising:
a concave/convex portion forming region in which at least one of concave portions and convex portions are formed on a surface of the electrophotographic photosensitive member from a central portion to both end portions in an axial direction of the electrophotographic photosensitive member, wherein
0.011≤( L max− L min)/ L max≤0.087 and 0.100≤( L max− L min)/ P≤ 0.333
where Lmax and Lmin are respectively maximum and minimum values of a distance L from the central portion to one end portion of the concave/convex portion forming region in the axial direction of the surface of the electrophotographic photosensitive member, and P is a diameter of the electrophotographic photosensitive member, and
a ratio of an area of the concave/convex portion forming region to an area of region A is 20 to 80% where region A is a region in an axial end portion of the surface of the electrophotographic photosensitive member that is sandwiched between a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmin is measured, and a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmax is measured.
4. An electrophotographic apparatus, comprising:
a cylindrical electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, a transfer unit, and a cleaning unit having a cleaning blade disposed in contact with the electrophotographic photosensitive member; and
the electrophotographic photosensitive member comprising a concave/convex portion forming region in which at least one of concave portions and convex portions are formed on a surface of the electrophotographic photosensitive member from a central portion to both end portions in an axial direction of the electrophotographic photosensitive member, wherein
0.011≤( L max− L min)/ L max≤0.087 and 0.100≤( L max− L min)/ P≤ 0.333
where Lmax and Lmin are respectively maximum and minimum values of a distance L from the central portion to one end portion of the concave/convex portion forming region in the axial direction of the surface of the electrophotographic photosensitive member, and P is a diameter of the electrophotographic photosensitive member, and
a ratio of an area of the concave/convex portion forming region to an area of region A is 20 to 80% where region A is a region in an axial end portion of the surface of the electrophotographic photosensitive member that is sandwiched between a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmin is measured, and a surface perpendicular to the axial direction of the electrophotographic photosensitive member at an end position of the concave/convex portion forming region where Lmax is measured.