Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus
A cylindrical electrophotographic photosensitive member having concave portions on a surface thereof includes a region A having concave portions at an end portion in an axial direction of the photosensitive member and a region B having concave portions different from those in the region A in a direction toward a center of the axial direction of the photosensitive member from the region A, wherein in the region A, an average value L1 is 20 to 200 μm, an average value W1 satisfies W1≤L1, an average value d1 is 1.7 to 4.0 μm, and an area ratio a1 is 5 to 65%; and in the region B, an average value L2 is 20 to 200 μm, an average value W2 satisfies W2≤L2, an average value d2 is 0.3 to 1.5 μm, and an area ratio a2 is 5 to 65%.
1. A cylindrical electrophotographic photosensitive member having a plurality of concave portions on a surface thereof, comprising:
a region A having a plurality of concave portions, at an end portion in an axial direction of the electrophotographic photosensitive member; and
a region B having a plurality of concave portions different from those in the region A, in a direction toward a center of the axial direction of the electrophotographic photosensitive member from the region A, wherein
in the region A, an average value L1 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W1 of maximum widths of opening parts of the concave portions in an axial direction of the electrophotographic photosensitive member satisfies W1≤L1,
an average value d1 of depths of the concave portions is 1.7 μm to 4.0 μm, and
an area ratio a1 of the concave portions is 5% or more and 65% or less; and
in the region B, an average value L2 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W2 of maximum widths of opening parts of the concave portions in the axial direction of the electrophotographic photosensitive member satisfies W2≤L2,
an average value d2 of depths of the concave portions is 0.3 μm to 1.5 μm, and
an area ratio a2 of the concave portions is 5% or more and 65% or less.
2. The electrophotographic photosensitive member according to claim 1 , wherein when a length of the axial direction of the electrophotographic photosensitive member is defined as 1.00 and the position on the electrophotographic photosensitive member in the axial direction is expressed by a value of 0.00 to 1.00, the position on the electrophotographic photosensitive member comprising the region A in the axial direction is 0.02 to 0.08 or 0.92 to 0.98.
3. The electrophotographic photosensitive member according to claim 1 , wherein a contour of the opening of the concave portion has an apex having an angle α which exceeds 0° and is 90° or less at least on an upstream side in a rotation direction of the electrophotographic photosensitive member; the width of the contour of the opening of the concave portion in the axial direction of the electrophotographic photosensitive member decreases toward the apex from the portion at which the width becomes maximum; and the depth of the concave portion decreases toward the apex from the deepest point of the concave portion, when the concave portion is viewed from the axial direction.
4. The electrophotographic photosensitive member according to claim 1 , wherein the area ratio a1 of the concave portion in the region A is 40% or more and 65% or less.
5. A process cartridge
integrally supporting a cylindrical electrophotographic photosensitive member having a plurality of concave portions on a surface thereof and at least one unit 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, wherein
the electrophotographic photosensitive member comprises: a region A having a plurality of concave portions, at an end portion in an axial direction thereof; and
a region B having a plurality of concave portions different from those in the region A, in a direction toward a center of the axial direction of the electrophotographic photosensitive member from the region A, wherein
in the region A, an average value L1 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W1 of maximum widths of opening parts of the concave portions in an axial direction of the electrophotographic photosensitive member satisfies W1≤L1,
an average value d1 of depths of the concave portions is 1.7 μm to 4.0 μm, and an area ratio a1 of the concave portions is 5% or more and 65% or less; and
in the region B, an average value L2 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W2 of maximum widths of opening parts of the concave portions in the axial direction of the electrophotographic photosensitive member satisfies W2≤L2,
an average value d2 of depths of the concave portions is 0.3 μm to 1.5 μm, and
an area ratio a2 of the concave portions is 5% or more and 65% or less.
6. An electrophotographic apparatus comprising:
a cylindrical electrophotographic photosensitive member having a plurality of concave portions on a surface thereof; a charging unit; an exposure unit; a developing unit; a transfer unit; and a cleaning unit having a cleaning blade that is arranged in contact with the electrophotographic photosensitive member, wherein
the electrophotographic photosensitive member comprises: a region A having a plurality of concave portions, at an end portion in an axial direction thereof; and
a region B having a plurality of concave portions different from those in the region A, in a direction toward a center of the axial direction of the electrophotographic photosensitive member from the region A, wherein
in the region A, an average value L1 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W1 of maximum widths of opening parts of the concave portions in an axial direction of the electrophotographic photosensitive member satisfies W1≤L1,
an average value d1 of depths of the concave portions is 1.7 μm to 4.0 μm, and
an area ratio a1 of the concave portions is 5% or more and 65% or less; and
in the region B, an average value L2 of maximum widths of opening parts of the concave portions in a circumferential direction of the electrophotographic photosensitive member is 20 μm to 200 μm,
an average value W2 of maximum widths of opening parts of the concave portions in the axial direction of the electrophotographic photosensitive member satisfies W2≤L2,
an average value d2 of depths of the concave portions is 0.3 μm to 1.5 μm, and
an area ratio a2 of the concave portions is 5% or more and 65% or less, wherein
an end portion of the image formable region in the axial direction of the electrophotographic photosensitive member is comprised in the region B.