A developing cartridge includes: a housing accommodating developing agent; a developing roller including a developing-roller shaft extending in a first direction; an electrode made of an electrically conductive resin; and a first collar made of an electrically non-conductive resin. The electrode is positioned at one end portion of the housing in the first direction. The electrode is electrically connected to the developing-roller shaft. The first collar covers one end portion of the developing-roller shaft in the first direction. The first collar includes: a first arm extending in the first direction; and a first pawl configured to engage with the electrode. The first pawl protrudes from the first arm in a direction away from the developing-roller shaft. The first pawl is movable between: a first position at which the first pawl is in engagement with the electrode; and a second position at which the first pawl is separated from the electrode.

A memory holder cover holds a memory holder so as to be movable with respect to the memory holder cover. An electrical contact contacts an electrical contact surface of a memory from above in a state where a cartridge is located at an attached position at which the cartridge is attached to a main housing. The main housing includes a guide groove having upper and lower guide surfaces. The upper guide surface guides movement of a memory holder from above when the cartridge is attached and detached. The lower guide surface guides movement of the memory holder from below when the cartridge is attached and detached. In a state where the cartridge is located at the attached position, the electrical contact surface is parallel to at least part of the upper guide surface or at least part of the lower guide surface.

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.

An image forming apparatus includes: a developing cartridge including a casing, a first electrical contact surface, and a holder movable relative to the casing; a drum cartridge including a drum frame, a second electrical contact surface, and a holder movable relative to the drum frame; and a main frame having an opening and including first and second guide frames facing in a facing direction, a first main electrical contact capable of being electrically connected to one of the first and second electrical contact surfaces, and a second main electrical contact positioned closer to the opening in an attachment direction and capable of being electrically connected to the remaining one of the first and second electrical contact surfaces. A distance in the facing direction between the first and second guide frames is reduced as the first and second guide frames extend toward the first main electrical contact in the attachment direction.

An image forming apparatus includes an apparatus body including a main contact, and a main guide, and a cartridge including a memory contact, a moving unit moving into and out of the apparatus body in a first direction and including a frame to which the cartridge is attached, first and second protrusions protruding in a second direction orthogonal to the first direction from the end surface of the frame, an intermediate contact being in electrical contact with the memory contact, an unit contact being in electrical contact with the main contact, and a line conductor, the first protrusion being supported by the main guide of the apparatus body, the second protrusion being located above the first protrusion. At least part of the line conductor connecting the intermediate contact and the unit contact is located in a recess formed by the first protrusion, the second protrusion, and the end surface.

A replaceable unit for an electrophotographic image forming device includes a housing having a reservoir for holding toner. An electrical connector is positioned on a first side of the housing. The electrical connector includes an electrical contact for contacting a corresponding electrical contact in the image forming device and a magnetic sensor electrically connected to the electrical contact. The electrical connector is movable between a first position and a second position. When the electrical connector moves from the first position to the second position, the electrical contact of the replaceable unit moves from a retracted position to an operative position. When the electrical connector moves from the first position to the second position, the magnetic sensor moves from a misaligned position to an aligned position with a point in a path of movement of a magnet for sensing a magnetic field of the magnet.

A drum cartridge attachable to and detachable from a main frame of an image forming apparatus includes: a photosensitive drum; a drum frame; and a drum contact. The photosensitive drum is rotatable about a drum axis extending in a first direction. A toner cartridge including a storage medium having an electrical contact surface is attachable to and detachable from the drum frame. In a state where the toner cartridge is attached to the drum frame, the drum contact is movable in the first direction between: a separated position in which the drum contact is positioned away from the electrical contact surface; and a contacting position in which the drum contact is in contact with the electrical contact surface. The drum contact moves from the separated position to the contacting position in accordance with attachment of the drum cartridge to the main frame.

A drum cartridge mountable to an image forming apparatus in a mounting direction, the drum cartridge including: a frame having an opening, the frame allowing a toner cartridge to be attached, and the frame including a housing configured to accommodate therein a toner and a first storage medium including a first electric contact; a photosensitive drum; and a second storage medium including a second electric contact and located at an outer surface of the frame, and in a state where the toner cartridge is mounted to the frame, the first storage medium is exposed via the opening and the second storage medium is aligned with the first storage medium in the mounting direction of the drum cartridge.

In a developing cartridge, a first supporting member is attached to a housing and has a first developing supporting portion and a driving-force-receiving-member supporting portion, the first developing supporting portion being configured to rotatably support a first part of a rotational shaft, the driving-force-receiving-member supporting portion being configured to rotatably support a driving-force-receiving member. The second supporting member is attached to the housing and has a second developing supporting portion and a detection-rotational-body supporting portion, the second developing supporting portion being configured to rotatably support a second part of the rotational shaft, the detection-rotational-body supporting portion being configured to rotatably support a detection rotational body.

A developer cartridge includes a housing, a developing roller, an agitator, a memory, and a cover. The housing is configured to store toner therein and has one end portion and the other end portion in a first direction. The developing roller is rotatable about a first axis extending in the first direction. The agitator is rotatable about a second axis extending in the first direction. The agitator is positioned spaced apart from the developing roller. The memory includes an electrical contact surface. The electrical contact surface is positioned at an outer surface of the housing and at the one end portion of the housing in the first direction, and is disposed between the developing roller and the agitator in a second direction from the first axis toward the second axis. The cover has an opening open in the second direction and covers the electrical contact surface.