In an electrophotographic photosensitive member, wrinkles have a convex portion in which a linear shape portion having a length of 50 μm or longer exists, the linear shape portion is parallel to any one of L1 to L150 and L1651 to L1800, and each of L1 to L1800 intersects with the convex portion at a plurality of places, and at least two of the places have different intersection angles; and when height information of the wrinkles is subjected to a frequency analysis, and a two-dimensional power spectrum is obtained, a one-dimensional radial distribution function has at least one local maximum value, and when an angular distribution is calculated from the spectrum at a frequency of the local maximum value, the power values have a particular relationship.

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

A process cartridge includes a photosensitive member, a toner, and a developing roller, a surface layer of the photosensitive member has a Martens hardness of 245 to 300 N/mm.sup.2, the developing roller has a single-layered surface layer containing a substrate and a binder resin; when an elastic modulus of the binder resin in a first region is E1, and an elastic modulus of the binder resin in a second region is E2, E1≥200 MPa and 10 MPa≤E2≤150 MPa are satisfied; the elastic modulus in the second region continuously decreases from that in the first region; the toner comprises a toner particle and an external additive A; the external additive A is a silica particle having a major diameter of 40 to 400 nm; and a coverage of the external additive A with respect to surface of the toner particle is 5.0% or more.

An image forming apparatus includes: a photosensitive drum; a developing roller; a separation mechanism configured to switch a state of the photosensitive drum and the developing roller between a contact state and a separation state; a main memory storing therein a first rotation number and a second rotation number; and a controller configured to perform calculating a deterioration quantity of the photosensitive drum based on the first rotation number and the second rotation number in the main memory. A surface of the developing roller contacts a surface of the photosensitive drum in the contact state, whereas the surface of the developing roller is separated from the surface of the photosensitive drum in the separation state. The first rotation number is the number of rotations of the photosensitive drum in the contact state, and the second rotation number is the number of rotations of the photosensitive drum in the separation state.

A process cartridge for use with a main assembly of an electrophotographic image forming apparatus, the main assembly including a driving shaft, to be driven by a motor, having a rotational force applying portion, wherein the process cartridge is dismountable from the main assembly in a direction substantially perpendicular to an axial direction of the driving shaft, the process cartridge includes i) an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, the electrophotographic photosensitive drum being rotatable about an axis thereof; ii) process means actable on the electrophotographic photosensitive drum; iii) a coupling member engageable with the rotational force applying portion to receive a rotational force for rotating the electrophotographic photosensitive drum, the coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating the electrophotographic photosensitive drum to the electrophotographic photosensitive drum and a disengaging angular position in which the coupling member is inclined away from the axis of the electrophotographic photosensitive drum from the rotational force transmitting angular position, wherein when the process cartridge is dismounted from the main assembly of the electrophotographic image forming apparatus in a direction substantially perpendicular to the axis of the electrophotographic photosensitive drum, the coupling member moves from the rotational force transmitting angular position to the disengaging angular position.

An image forming apparatus includes a member having a certain function, a learned model, and an estimation unit. The learned model is obtained by learning of a self-organizing map model having an input layer and an output layer. The estimation unit gives multidimensional input data related to the member to the input layer, and estimates a state of the member on the basis of one of a plurality of nodes of the output layer.

An image carrier according to one or more embodiments may include: a cylindrical image carrier member including an outer circumferential surface formed with an image carrier layer configured to carry a developer image; one or more silencers disposed in the image carrier member; and a bonding member that bonds the one or more the silencers to an inner circumferential surface of the image carrier member. For each silencer, the inner circumferential surface of the image carrier member includes one or more bonding areas to which the bonding member is attached. A bonding range, in which the one or more bonding areas are fit, for each silencer, has a length thereof in an axial direction of the silencer being greater than a length thereof in a circumferential direction of the silencer.

Disclosed is a cylindrical electrophotographic photosensitive member having a region A along an outer surface and a region B along the outer surface. In this electrophotographic photosensitive member, the region A is located on an end side in an axial direction of the electrophotographic photosensitive member relative to the region B, the region A has a specific groove provided on the outer surface of the electrophotographic photosensitive member, an area ratio a1 of the groove is 65% to 100%, the region B has specific concave portions provided on the outer surface of the electrophotographic photosensitive member, and an area ratio a2 of the concave portion is 5% to 65%.

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

A device for transmitting a rotational force to an electrophotographic photosensitive drum includes a flange connectable to the photosensitive drum and having a rotational axis, a hollow portion, and a force receiving surface, a pin configured to transmit the rotational force to the flange, and a coupling member the coupling member including a shaft shaped portion extended along a rotational axis of the coupling member and including a through-hole portion. When the pin and at least a part of the shaft shaped portion of the coupling member are accommodated in the hollow portion of the flange and the pin contacts the force receiving surface, the pin is capable of transmitting the rotational force received from the coupling member to the flange.