A process cartridge comprises an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, and process means actable on the electrophotographic photosensitive drum. The process cartridge also includes a coupling member 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.

A rotating force transmitting part for an electrophotographic photosensitive drum for a main assembly of the electrophotographic image forming apparatus, wherein the main assembly of the electrophotographic image forming apparatus includes a driving shaft, to be driven by a motor, having the rotating force applying portion, and wherein the electrophotographic photosensitive drum is dismountable from the main assembly of the electrophotographic image forming apparatus in a direction substantial perpendicular with an axial direction of the driving shaft, the rotating force transmitting part includes a coupling member engageable with the rotational force applying portion to receive a rotational force for rotating the electrophotographic photosensitive drum in the state in which electrophotographic photosensitive drum is mounted to the main assembly of the electrophotographic image forming apparatus, wherein 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 rotatably supported photosensitive drum, a charging roller configured to charge the photosensitive drum, a developing sleeve configured to develop an electrostatic latent image formed on a surface of the photosensitive drum and collect toner adhered to the photosensitive drum, an electricity removal sheet disposed on a downstream from the charging roller in a direction of movement on a surface of the photosensitive drum and disposed on an upstream side from the developing sleeve and arranged in contact with the photosensitive drum, and an electricity removal high-voltage power supply configured to apply voltage to the electricity removal sheet. The electricity removal high-voltage power supply an image-forming period applies a DC bias having a polarity identical to a charging polarity of the photosensitive drum and having a lower absolute value than that of the charged potential of the photosensitive drum to electricity removal sheet.

In an image forming apparatus in which an electrostatic image is formed on an electrophotographic photosensitive member using at least a process of a pseudo halftone formed by dots as a method of representing gradation, the electrophotographic photosensitive member is provided on a surface thereof with a plurality of recessed portions of 0.5 μm more and 5 μm or less in depth and 20 μm or more and 80 μm or less in longest diameter of an opening, when a square region of 500 μm×500 μm is arbitrarily extracted on the surface of the electrophotographic photosensitive member, in the square region, a total area of the recessed portions is 10000 μm.sup.2 or more and 90000 μm.sup.2 or less and a total area of a flat portion contained in a portion other than the recessed portion is 80000 μm.sup.2 or more and 240000 μm.sup.2 or less, and an arrangement (A) of the plurality of recessed portions is such an arrangement that an image quality lowering index (f) calculated by specific processing is 14% or less.

The present invention provides a cartridge which is dismountable from the main assembly without deteriorating usability performance in a predetermined direction substantially perpendicular to the rotational axis of an image bearing member, the main assembly being not provided with the mechanism for moving the main assembly side engaging portion in the rotational axis direction in response to the opening and closing operation of the main assembly cover of the main assembly.

With the movement of the cartridge in such a direction perpendicular to the rotational axis of the image bearing member in the dismounting of the cartridge from the main assembly of the electrophotographic image forming apparatus, the coupling member movable in a direction parallel with the rotational axis of the image bearing member enters a inside of a recess of the main assembly side engaging portion provided in the main assembly of the apparatus to receive a rotational force from the main assembly side engaging portion.

The electrophotographic photosensitive member has: a cylindrical support; a charge generating layer formed on the cylindrical support; and a charge transport layer formed on the charge generating layer, the charge generating layer contains a hydroxygallium phthalocyanine crystal having a particular CuKα characteristic X-ray diffraction peak, a titanyl phthalocyanine crystal having a particular CuKα characteristic X-ray diffraction peak or a chlorogallium phthalocyanine crystal having a particular spectral absorption spectrum as a charge generating material, and in the charge generating layer, with respect to the film thickness of the charge generating layer, when a region from the central position of an image forming area to the end position of the image forming area is divided in the axial direction of the cylindrical support into five equal regions and the average film thickness of the charge generating layer in each region satisfies a specific condition.

The electrophotographic electroconductive member includes a support having an electroconductive outer surface, and an electroconductive layer on the surface of the support. The electroconductive layer has a matrix containing a crosslinked product of a first rubber, and domains dispersed in the matrix, and the domains each contain a crosslinked product of a second rubber and electroconductive particles. The matrix has a volume resistivity R1 of more than 1.0×10.sup.12 Ω.Math.cm, and the domains each have a volume resistivity R2 lower than the volume resistivity R1 of the matrix. The electroconductive layer further has a pore, and an inner wall of the pore is constituted by a part of the matrix and a part of the domains. The domains constituting the inner wall protrude into the pore at sites on the inner wall.

A drum cartridge includes: a drum frame to which a developing cartridge is attachable; a photosensitive drum rotatable about an axis extending in a first direction; a memory having an electrical contact surface; and a resilient member positioned between the electrical contact surface and the drum frame. The resilient member is configured to expand and compress in a second direction crossing the electrical contact surface between a first state and a second state, the resilient member having a shorter length in the second state than in the first state. A distance between the drum frame and the electrical contact surface in the second direction when the resilient member is in the second state is smaller than a distance between the drum frame and the electrical contact surface in the second direction when the resilient member is in the first state.

A contact-separation mechanism includes a cam to rotate to move a contact-separation member to and from a counterpart member, a detection target to rotate together with the cam, and a detector to detect presence or absence of the detection target in a detection area of the detector, and circuitry. The cam has a reference range. The circuitry issues a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area, and sets the target time based on a duration of an immediately preceding passing of the reference range through the detection area.

An electro-conductive member for an electrophotographic image forming apparatus for which a change in resistance value is small even when a large current is applied at a high voltage for a long period of time is provided. The electro-conductive member includes a support having an electro-conductive outer surface and an electro-conductive layer on the outer surface of the support, in which the electro-conductive layer has a matrix including a cross-linked product of a first rubber and domains dispersed in the matrix, the domains include a cross-linked product of a second rubber different from the first rubber and an electrically conductive agent, and the cross-linked product of the second rubber has, in a molecule, a structural unit represented by Structural Formula (I).

[—(CH.sub.2).sub.n—O—]  Structural Formula (I)

In Structural Formula (I), n is an integer of 1 to 3.