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 developing device configured to develop a latent image formed on a surface of an image bearer includes a rotator, a bearing, a holder, a first regulator, and a second regulator. The rotator includes a rotation shaft. The bearing supports the rotation shaft. The holder holds the bearing. The first regulator, disposed on any one of the bearing and the holder, regulates movement of the bearing such that the bearing does not fall toward one end side in an axial direction of the rotation shaft relative to the holder. The second regulator regulates movement of the bearing such that the bearing does not fall toward another end side in the axial direction relative to the holder after the bearing is attached to the holder.

An image forming apparatus includes: a main frame; a developing cartridge including a casing, a storage medium having an electrical contact surface, and developing roller; a photosensitive drum contactable with the developing roller; an electrical connector contactable with the electrical contact surface; a separation mechanism; and a controller configured to communicate with the storage medium via the electrical connector. The separation mechanism is configured to move the casing relative to the main frame in a separating direction in which the developing roller separates from the photosensitive drum. The controller is configured to perform: moving, by controlling the separation mechanism, the casing relative to the main frame in the separating direction; determining, in response to performing the moving, whether communication with the storage medium is established; and outputting, when determining in the determining that the communication with the storage medium is not established, an error.

There are demands for stable connections of contact points between a process cartridge, including a development device, and an image forming device. A development contact point, a first contact point, and a second contact point are disposed in this order on the inside in a perpendicular direction with respect to an insertion direction in which a development device is inserted into an image forming apparatus.

A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the fourth frame plate.

A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the fourth frame plate.

A process cartridge includes a developing cartridge and a drum cartridge. The developing cartridge includes: a casing; a developing roller rotatable about a developing axis extending in a first direction; and a development-side IC chip having a development-side electrical contact surface. The drum cartridge includes: a drum frame; a photosensitive drum rotatable about a drum axis extending in the first direction; a drum-side IC chip having a drum-side electrical contact surface; and a lock lever configured to lock the developing cartridge to the drum frame. The development-side electrical contact surface and the drum-side electrical contact surface are positioned opposite to the lock lever with respect to the casing in the first direction in a state where the developing cartridge is attached to the drum frame.

A cartridge mountable to and dismountable from a main assembly of an image forming apparatus includes a memory, a guide configured to guide a portion-to-be-guided provided in the main assembly and to guide a main assembly contact provided in the main assembly to a memory contact of the memory when the cartridge is mounted in the main assembly, and a grip portion. The guide is provided at a bottom of the cartridge when the cartridge is hung by gripping the grip portion and constitutes a part of a supporting portion configured to support the cartridge when the cartridge is placed on a horizontal placement surface. The guide has a chamfered surface formed by being chamfered. When the cartridge is supported at the supporting portion, the chamfered surface opposes the horizontal placement surface, and a surface of the memory contact is inclined with respect to the horizontal placement surface.

A process cartridge includes a developing cartridge and a drum cartridge. The developing cartridge includes: a casing; a developing roller rotatable about a developing axis extending in a first direction; and a development-side IC chip having a development-side electrical contact surface. The drum cartridge includes: a drum frame; a photosensitive drum rotatable about a drum axis extending in the first direction; a drum-side IC chip having a drum-side electrical contact surface; and a lock lever configured to lock the developing cartridge to the drum frame. The development-side electrical contact surface and the drum-side electrical contact surface are positioned opposite to the lock lever with respect to the casing in the first direction in a state where the developing cartridge is attached to the drum frame.

There are demands for stable connections of contact points between a process cartridge, including a development device, and an image forming device. A development contact point, a first contact point, and a second contact point are disposed in this order on the inside in a perpendicular direction with respect to an insertion direction in which a development device is inserted into an image forming apparatus.