An image forming apparatus includes a main body including a first guide portion and a second guide portion, a process cartridge including a photosensitive drum, a support frame configured to support the process cartridge and move between an inside position and an outside position. The support frame includes a first side frame. The first side frame includes a first guided portion to be guided by the first guide portion. The second side frame includes a second guided portion guided by the second guide portion A dimension of the first side frame is greater than or equal to a dimension of the first side frame. A dimension of the second side frame is greater than or equal to a dimension of the second side frame.

A developing cartridge includes: a casing configured to store developer; a developing roller configured to rotate about a first axis extending in a first direction; a shaft provided at one end of the casing in the first direction; and an electrode configured to rotate about the shaft and supply power to the developing roller. The shaft extends in the first direction and has a peripheral surface. The electrode has a first protrusion configured to rotate together with the electrode, the first protrusion extending along a portion of the peripheral surface of the shaft.

A developing cartridge includes a developing roller with a shaft, a housing with a wall portion, a developing electrode, a first contact portion, a second contact portion, and a connecting portion. The developing electrode includes a first contact portion contacting the shaft and has a first surface against which an apparatus electrode of an image forming apparatus body slides, a second contact portion disposed next to the first contact portion, and a second surface configured to contact an electrode of the image forming apparatus. The connecting portion includes a first inclined surface connecting the first surface and the second surface with each other and being contiguous with the first surface. The first inclined surface is inclined toward the second contact portion from the first contact portion such that the first inclined surface extends in a direction away from the wall portion.

An image forming apparatus includes an apparatus main body, a conductive member, a contact spring, a hollow cylinder, and a drum unit attachable to and detachable from the apparatus main body. The conductive member is disposed in the drum unit. The contact spring is disposed in the apparatus main body and comes in electrically conductive contact with the conductive member. The hollow cylinder is disposed in the apparatus main body. The contact spring has a contact part and a helical spring part. The contact part is provided on the helical spring part. The contact part is retractable in and out of the hollow cylinder. The helical spring part is contained in the hollow cylinder and urges the contact part in a direction for causing the contact part to protrude from the hollow cylinder. The contact part has a longitudinal shape elongated along an axis of the helical spring part.

Disclosed in the present invention is a developing cartridge, which is detachably mounted in an image forming device, comprising: a housing; a developing roller rotatably supported by the housing, the developing roller rotating about an axis extending in a first direction; a supply roller rotatably supported by the housing and configured to convey a developer to the developing roller, the supply roller having a supply roller shaft made of metal; a driving gear disposed on a driving side of the housing in the first direction; and an electrode electrically connected to the developing roller shaft, comprising a first part, a second part, and an intermediate electrical connection part connecting the first part and the second part; wherein the first part is located on an opposite side of the driving side of the housing, the second part is located on the driving side of the housing, and the opposite side of the driving side and the driving side are opposite ends of the housing in the first direction; and the second part is simultaneously in contact with the supply roller shaft and the developing roller shaft.

A developing cartridge includes a casing, a rotating member, and an electrode member. The casing may be configured to accommodate therein developer. The rotating member has a rotational shaft extending in an axial direction. The rotating member is configured to rotate about the rotational shaft and carries the developer thereon. The electrode member is configured to be electrically connected to the rotating member. The electrode member covers at least part of the rotational shaft from an orthogonal direction orthogonal to the axial direction and is arranged to confront the casing in the axial direction. The electrode member is configured to move in the orthogonal direction in accordance with a movement in the axial direction.

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.

A drum cartridge includes: a photosensitive drum rotatable about an axis extending in a first direction; a first drum frame to which a developing cartridge is attachable; and a second drum frame having an outer surface; and a memory having an electrical contact surface. The first drum frame is at one end portion of the drum cartridge in a second direction and the second drum frame is at another end portion of the drum cartridge in the second direction. The electrical contact surface is positioned at the outer surface of the second drum frame and is movable in a predetermined direction relative to the second drum frame.

A developing cartridge includes: a casing configured to accommodate therein toner; a developing roller; a supply roller configured to supply the toner to the developing roller; a layer thickness regulation blade in contact with a circumferential surface of the developing roller; a developing electrode electrically connected to the developing roller; and a supply electrode electrically connected to the supply roller and the layer thickness regulation blade. The supply electrode includes: an electrode member electrically connected to a rotation shaft of the supply roller and movable in a direction perpendicular to the rotation shaft; and a connection member in contact with and electrically connecting the electrode member and the layer thickness regulation blade. The electrode member is movable relative to the connection member in the direction perpendicular to the rotation shaft in a state where the electrode member is in contact with the connection member.

An image forming apparatus includes: a process cartridge; and an apparatus main body to which the process cartridge is attachable and from which the process cartridge is detachable. The process cartridge includes: a photoconductive drum, and an electrode connected to the photoconductive drum and having a contact surface facing downward. The apparatus main body includes: a support frame supporting one end portion of the process cartridge in an axis direction of the photoconductive drum, a ground metal plate supported by the support frame and connected to ground, and a spring supported by the support frame and configured to contact with the contact surface of the electrode from below to connect the electrode and the ground metal plate.