A drum cartridge includes a drum cover movable relative to a photosensitive drum between a first position at which the drum cover covers a part of a circumferential surface of the photosensitive drum and a second position at which the drum cover does not cover the part of the circumferential surface. The drum cover is located at an opposite side of a toner cartridge with respect to the photosensitive drum in a state where the toner cartridge is attached to the drum cartridge and the drum cover is located at the second position. The drum cover is located at the first position in a state where the drum cartridge is attached to a drawer and the drawer is located at a pulled-out position and located at the second position in a state where the drum cartridge is attached to the drawer and the drawer is located at an accommodated position.

A driving force transmission mechanism is a mechanism for transmitting rotational force of the second rotor having a driving-side coupling to a first rotor having a driven-side coupling. The driving-side coupling includes a body and a plurality of second engaging members engaging with first engaging members of the driven-side coupling, each of the plurality of second engaging members has at an abutting point on an abutting surface of a corresponding first engaging member a first inclined surface inclined so as to be away from a rotation axis of the body from a downstream side toward an upstream side in a rotation direction of the body.

An image forming apparatus includes a main body provided with a mounting portion and an interference member, and a toner cartridge inserted into the mounting portion. The toner cartridge includes a housing containing toner, a coupling portion, a front cover coupled to one end of the housing via the coupling portion, and a switching member to weaken a coupling force of the coupling portion by interfering with the interference member when the toner cartridge is mounted on the mounting portion.

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 housing, a drawer, and a drum unit. The drawer is movable between an accommodated position at which the drawer is accommodated in the main housing and a pulled-out position at which the drawer is pulled out from the main housing. The drum unit is attachable to the drawer in a state where the drawer is located at the pulled-out position. The drum unit includes a first photosensitive drum, a second photosensitive drum, and a waste toner pipe allowing passage of waste toner from the first photosensitive drum and waste toner from the second photosensitive drum.

An electroconductive elastic body includes: a cross-linked product of a first ionic electro-conductive rubber, a cross-linked product of a second ionic electro-conductive rubber, and at least one of a fatty acid and a fatty acid metal salt; wherein the electroconductive elastic body has a matrix that includes the cross-linked product of the first ionic electro-conductive rubber, and a domain that includes the cross-linked product of the second ionic electro-conductive rubber; the cross-linked product of the second ionic electro-conductive rubber includes a polyether skeleton; an electrical resistance of the domain is lower than an electrical resistance of the matrix; in a waveform separation profile of the elastic body as obtained by a small-angle X-ray scattering method, A2 and A1 satisfy a relationship expressed by the following expression (1):
0.005≤(A2×C2/A1×C1)≤0.030  (1).

A system includes a drive gear and a sensor mounted in an image forming device and a replaceable unit removably installable in the image forming device. The replaceable unit includes a gear for receiving rotational force from the drive gear. The system includes an encoded member encoded with identifying information of the replaceable unit and operatively connected to the gear such that rotation of the gear causes movement of the encoded member for communicating the identifying information of the replaceable unit to the sensor. The encoded member is configured to move toward the sensor upon rotation of the gear of the replaceable unit in a first rotational direction for communicating the identifying information of the replaceable unit to the sensor. The encoded member is configured to move away from the sensor upon rotation of the gear of the replaceable unit in a second rotational direction opposite the first rotational direction.

A replaceable unit includes a rotatable gear positioned on a housing of the replaceable unit and an encoded member encoded with identifying information of the replaceable unit. The encoded member is positioned on an axially outboard face of the gear such that the encoded member is rotatable with the gear for communicating the identifying information of the replaceable unit to a sensor of an image forming device when the replaceable unit is installed in the image forming device. The encoded member is configured to move axially outward relative to a rotational axis of the gear upon rotation of the gear in a first rotational direction for communicating the identifying information of the replaceable unit to the sensor. The encoded member is configured to move axially inward relative to the rotational axis of the gear upon rotation of the gear in a second rotational direction opposite the first rotational direction.

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.

An image forming apparatus includes a main casing, a cartridge, and a controller. The cartridge is attachable to the main casing. The cartridge includes a cartridge memory configured to store identification information. The controller is configured to perform a rewriting process to rewrite the identification information to information indicating that the cartridge is the normal cartridge, in a case where the controller receives a cancellation instruction to instruct to cancel the service contract and the identification information, which is stored in a cartridge memory of the cartridge attached to the main casing, indicates that the cartridge is the contract cartridge.