A fluorine-containing resin particle contains 0 or more and 30 or less carboxyl groups per 10.sup.6 carbon atoms and 0 ppm or more and 3 ppm or less of a basic compound.

An image forming apparatus includes a housing, a top cover having an opening, a process cartridge attachable to the housing, a toner cartridge attachable to the process cartridge, and an interlocking mechanism. The top cover is pivotally movable between a first position closing the opening and a second position opening the opening. In a state where the toner cartridge is attached to the process cartridge, the toner cartridge is pivotally movable between an attachment/detachment position where the toner cartridge is attachable to and detachable from the process cartridge; and a fixed position where the toner cartridge is fixed to the process cartridge. The interlocking mechanism is configured to pivotally move the toner cartridge to the attachment/detachment position when the top cover is moved to the second position, and to pivotally move the toner cartridge to the fixed position when the top cover is moved to the first position.

A process cartridge includes a photosensitive drum; a developing roller; a developer supplying roller, provided in contact with the developing roller; a driving force receiving portion provided at a shaft end of the supplying roller; a first driving force transmitting portion; a second driving force transmitting portion; flexible sheets provided adjacent to an engaging portion between the first portion and the second portion to intermittently contact the second portion with rotation of the second portion, wherein a rotational direction of the roller is opposite to that of the roller, and a peripheral speed of the roller is larger than that of the roller.

An image forming apparatus includes drum shafts supported by a main body, drum cartridges insertable and removable in an axial direction, a regulation side plate having bearings, a projecting portion provided to one of the regulation side plate and the main body, a fitting portion, and an urging force imparting portion. The urging force imparting portion is provided to the regulation side plate in an array direction of the bearings to impart an urging force that urges the regulation side plate toward the main body. At least a part of the urging force imparting portion is provided at a position for imparting the urging force on, with respect to the bearings, a side opposite to a position at which one of the projecting portion and the fitting portion is provided, in a direction orthogonal to the array direction of the bearings and the axial direction of each drum shaft.

A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a drum unit containing the drum, a developing unit containing the roller and being movable so the roller contacts and is spaced from the drum, and a first force receiver receiving a force from a main-assembly first force applier by movement of a door from open to closed positions when mounting the cartridge and a second force receiver movable from a stand-by position by movement of the first force receiver by a force received from the first force applier. The second force receiver takes a projected position receiving a force from the second force applier to move the developing unit so the roller moves out of contact with the drum, the projected position being higher than the stand-by position.

An image forming apparatus includes a body casing, a pressing member, a process cartridge, and a drawer. The body casing includes a positioning member. The pressing member is disposed inside the body casing. The process cartridge includes a photosensitive drum. The drawer is configured to support the process cartridge and to move, in a sliding direction orthogonal to an axis direction of the photosensitive drum, between an inside position that is a position inside the body casing and an outside position that is a position outside the body casing. The process cartridge includes an engagement portion and a spring. The engagement portion is configured to be positioned by the positioning member. The spring is configured to be pressed by the pressing member such that the engagement portion is pressed toward the positioning member.

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%.

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a lamination type photosensitive layer disposed on the undercoat layer and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material and a polyester resin, and in a case where an average thickness of the charge transport layer is defined as As (μm) and an average thickness of the undercoat layer is defined as Bs (μm), expressions 27≤As≤50, 10≤Bs≤40, and 0.70≤As/Bs≤4.80 are satisfied.

An electrophotographic photosensitive member includes a conductive support and a photosensitive layer disposed on the conductive support. A top surface layer of the electrophotographic photosensitive member includes fluorine-containing resin particles, a fluorine-containing dispersant, and two or more charge transporting materials. When the charge transporting materials are listed in order of decreasing HOMO energy levels, a difference in HOMO energy level between each adjacent two of the charge The ratio A of the amount of each of the charge transporting materials to the total amount of the charge transporting materials satisfies the condition 1 below,
[(100/N)−(100/N×0.3)]≤A≤[(100/N)+(100/N×0.3)]  Condition 1 where N represents the number of types of the charge transporting materials included in the top surface layer.

There is provided a printing apparatus including: an installing part in which a consumable item to be used in printing is to be installed; a printer configured to print an image on a printing medium by using the consumable item installed in the installing part; and a controller. The printing apparatus is configured to operate in a contract mode based on content of a contract regarding the consumable item to be used in the printing. The controller is configured to execute a profit returning process of performing profit return according to the content of the contract in a case that the consumable item installed in the installing part has a type corresponding to a non-contract mode not based on the content of the contract and that the printing apparatus is operated in the contract mode.