A developing device includes a frame, a cylindrical developer carrying member rotatably supported by the frame and configured to carry a developer containing toner particles, and a regulating member fixed to the frame at one end thereof and including a contact portion which contacts the developer carrying member at the other end of the regulating member and which forms a contact nip between the regulating member and the developer carrying member. When a position of the contact portion where a maximum of a pressure distribution of the contact portion to the developer carrying member with respect to a rotational direction of the developer carrying member is indicated is a reference position, the contact portion includes a first surface portion positioned upstream of the reference position and a second surface portion positioned downstream of the reference position with respect to the rotational direction.

A lubricant replacement case for an image forming apparatus includes a housing including a plurality of storage compartments to accommodate at least one lubricant unit. The plurality of storage compartments include at least one storage compartment for unused lubricant to be inserted into the image forming apparatus and at least one storage compartment for used lubricant to be retrieved from the image forming apparatus.

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 main body; a toner cartridge having a first opening; a process cartridge having a photosensitive drum and a second opening; a positioning part; a transfer unit; and an urging member. The toner cartridge and process cartridge are attachable to and detachable from the main body in an axial direction of the photosensitive drum. The positioning part and transfer unit are positioned above the process cartridge attached to the main body. The positioning part fixes the attached process cartridge in position relative to the main body. The urging member urges the attached process cartridge toward the positioning part and urges the process cartridge such that the toner can be supplied from the toner cartridge to the process cartridge through the first opening and the second opening when the toner cartridge and the process cartridge are attached to the main body.

An image forming apparatus includes first and second image forming portions and a belt. The first and second image forming portions include first and second image bearing members, and first and second transferring members, respectively. The belt nips and feeds a recording material. The first image forming portion is disposed upstream of the second image forming portion in a moving direction of the recording material, and a plurality of members including the first and second image bearing members are integrally assembled and are mountable on or dismountable from a main assembly of the image forming apparatus. A film thickness of a surface of the first image bearing member is larger than a film thickness of a surface of the second image bearing member, circumferential speed ratios or contact pressures of rotating components differ, and/or mass ratios of components of respective developers differ.

An image forming apparatus, having a first photosensitive drum, a first developing roller, a first shifting member movable between a contacting position and a separating position, a motor, a first joint, a first clutch operable in one of a transmittable condition and a discontinuing condition, a first shifting cam rotatable between a first position, in which the first shifting cam locates the first shifting member at the contacting position, and a second position, in which the first shifting cam locates the first shifting member at the separating position, and a first switching cam rotatable between a third position, in which the first switching cam places the first clutch in the transmittable condition, and a fourth position, in which the first switching cam places the first clutch in the discontinuing condition, alongside the first shifting cam rotating between the first position and the second position, is provided.

An image forming apparatus includes: a main body casing having an opening; a cover movable between a closing position to close the opening and an opening position to open the opening; and a process cartridge detachably attachable to the main body casing through the opening while the cover is at the opening position. The process cartridge includes: a photosensitive drum; a developing device; a toner receiving part; and a toner conveying part. The toner receiving part has a first end portion and a second end portion. The first end portion has a receiving opening for receiving toner. When the cover is at the closing position and the process cartridge is in the attached state, the first end portion is outside the main body casing while the second end portion is inside the main body casing. The toner conveying part conveys toner in the toner receiving part to the developing device.

Provided is a processing cartridge detachably installed in an imaging device. The processing cartridge includes a first unit and a second unit, and a movable assembly coupled to and receive force from the force applying portion. When the processing cartridge is assembled to the imaging device, the first t and second units can be switched between states of approaching and separating. The movable assembly comprises an installing part and an acting part movable relative to and connectable with each other. The movable assembly is installed in the processing cartridge by the installing part, the acting part is coupled to the force applying portion and receives force from the force applying portion, to force the first and second units to switch between the two states. The acting part is retractable relative to the installing part and comprises an acting block and a guide block guided by the installing part.

The image forming apparatus includes a drum cartridge having a photosensitive drum and a drum drive input member; a developing cartridge configured to be movably mounted to the drum cartridge, the developing cartridge comprising a developing roller disposed so as to face the photosensitive drum and a developing drive input member; a drum drive transmission member configured to engage with the drum drive input member and configured to transmit drum driving force to the drum drive input member while permitting a positional gap of the drum drive input member within a predetermined range; and a developing drive transmission member configured to engage with the developing drive input member and configured to transmit developing driving force to the developing drive input member while permitting a positional gap of the developing drive input member within a predetermined range.

An image-forming apparatus includes a coupling recess to be engaged with a coupling protrusion to rotate the coupling protrusion, a second gear portion to be engaged with a gear to rotate the gear, and a driving force transmitter that is rotatable about a predetermined rotational axis. A torque required to rotate the gear is larger than a torque required to rotate the second gear portion in a state where the coupling recess does not engage the coupling protrusion.