A toner cartridge according to one example embodiment includes a housing having a reservoir for holding toner. A first electrical contact and a second electrical contact are positioned on a first longitudinal end of the housing. The first electrical contact is electrically connected to processing circuitry positioned on the housing. The second electrical contact is electrically connected to an imaging component positioned on the housing. The first electrical contact is positioned higher than the second electrical contact. A first drive coupler and a second drive coupler are positioned on a second longitudinal end of the housing. The first electrical contact and the second electrical contact are positioned higher than a first rotational axis of the first drive coupler. The first electrical contact is positioned higher than a second rotational axis of the second drive coupler and the second electrical contact is positioned lower than the second rotational axis.

A developing cartridge includes: a casing; a developing roller; a developing electrode; a gear; a rack gear including a protrusion; and a cam having first and second cam surfaces. The rack gear meshes with the gear and is movable in a direction from one end toward another end of the casing. The cam is movable from a first position to a second position. The first cam surface of the cam at the first position contacts the protrusion, and causes the cam to move to the second position as the rack gear moves in the direction in a state where the first cam surface is in contact with the protrusion. A second cam surface moves the developing electrode in a direction away from the cam different from moving directions of the rack gear and the cam while contacting the developing electrode as the cam moves to the second position.

A cartridge includes: a housing; a storage medium having an electrical contact surface; and a holder movable relative to the housing. The holder includes a first holder member. and a second holder member movable relative to the first holder member. The first holder member includes at least one pawl and holds the electrical contact surface at one end surface of the first holder member in a first direction crossing the electrical contact surface. The second holder member includes at least one corner part engageable with the at least one pawl to provide an engaging portion therebetween. The second holder member has a through-hole that is open at another end face of the second holder member in the first direction. The engaging portion is accessible from an outside of the holder through the through-hole.

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 drum cartridge includes: a drum frame to which a developing cartridge is attachable; a photosensitive drum; and a first storage medium. The drum frame has one end portion and another end portion spaced apart from the one end portion in a first direction. The photosensitive drum is rotatable about a first axis extending in a second direction and is positioned at the one end portion of the drum cartridge. The first storage medium includes a first electrical contact surface. The first storage medium is positioned at an outer surface of the drum frame, the outer surface being exposed in a state where the developing cartridge is attached to the 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.

A developing cartridge includes a developing electrode and a supply electrode. The developing electrode includes a first electrical contact in contact with a developing roller shaft, and a second electrical contact positioned closer to the developing roller shaft than a second agitator gear is to the developing roller shaft. The second electrical contact is positioned farther from the developing roller shaft than the first electrical contact is from the developing roller shaft. The supply electrode includes a first electrical contact in contact with the supply roller shaft, and a second electrical contact positioned closer to the developing roller shaft than the second agitator gear is to the developing roller shaft. The second electrical contact of the supply electrode is positioned farther from the developing roller shaft than the second electrical contact of the developing electrode is from the developing roller shaft.

A toner cartridge according to one example embodiment includes a housing having a reservoir for holding toner. A first electrical contact and a second electrical contact are positioned on a first longitudinal end of the housing. The first electrical contact is electrically connected to processing circuitry positioned on the housing. The second electrical contact is electrically connected to an imaging component positioned on the housing. The first electrical contact is positioned higher than the second electrical contact. A first drive coupler and a second drive coupler are positioned on a second longitudinal end of the housing. The first electrical contact and the second electrical contact are positioned higher than a first rotational axis of the first drive coupler. The first electrical contact is positioned higher than a second rotational axis of the second drive coupler and the second electrical contact is positioned lower than the second rotational axis.

An image forming apparatus includes an apparatus body, a first unit, a second unit, a cover, and a restrictor. The apparatus body includes a body-side connection terminal. The first unit is detachably attached to the apparatus body. The second unit detachably attached to the first unit and includes a unit-side connection terminal. The cover covers the body-side connection terminal disposed in the apparatus body and is movable between a covering position at which the cover covers the body-side connection terminal and a retracted position at which the cover is retracted from the covering position. The restrictor restricts movement of the cover from the covering position to the retracted position in a state in which the first unit is detached from the apparatus body.