A toner container includes a container main body, a first toner storage portion, a second toner storage portion, and a gripping portion. The container main body is elongated. The first toner storage portion stores toner in its inside and is provided in one side in a longitudinal direction of the container main body. The second toner storage portion stores toner in its inside and is provided in the other side in the longitudinal direction. The gripping portion is provided between the first toner storage portion and the second toner storage portion, and includes a concave portion which is formed in a side portion of the container main body on one side in a width direction of the container main body, the width direction being perpendicular to the longitudinal direction.

According to one embodiment, the developing device includes a developing case containing toner, a mixer configured to diffuse the toner in the developing case, and a developing roller configured to develop a latent image formed on an image carrier. The developing case includes a circulation path through which air containing the toner flows. The developing roller is partially exposed from the developing case. The developing roller includes a sleeve rotating along with the movement of the image carrier and a plurality of magnetic pole portions disposed inside the sleeve. The developing roller holds the toner on the sleeve and supplies the toner to the image carrier to develop the latent image. The developing device further includes a magnet disposed apart from the developing roller. The magnet faces one of the magnetic pole portions across the sleeve.

A developing cartridge is provided. The developing cartridge includes a housing which accommodates developer therein, a receiving member provided which couples with a force output member of an image forming apparatus to receive a driving force, a developing roller which rotates by the driving force received by the receiving member; a detectable rotary member having a first detectable portion and a second detectable portion and rotates by the driving force from a first rotational position where the first detectable portion is detected by a detection member provided in the image forming apparatus to a second rotational position where the second detectable portion is detected by the detection member, and a cut-off mechanism which cuts off a transmission of the driving force from the receiving member to the detectable rotary member in a state where the detectable rotary member is positioned in the second rational position.

A cartridge for an electrophotographic image forming apparatus includes a developing roller, a rotatable member for transmitting a rotational force to the developing roller, a coupling member, and a frame. The coupling member is capable of moving between a first coupling member position in which the coupling axis is substantially coaxial with the rotational axis of the rotatable member and a second coupling member position in which the coupling axis is not coaxial with the rotational axis of the rotatable member. When the frame is in a first frame position, the coupling member is in the first coupling member position and a rotational force receiving portion of the coupling member engages with a rotational force applying portion of the apparatus, and, when the frame is in the second frame position, the coupling member is in the second coupling member position and the rotational force receiving portion engages with the rotational force applying portion.

A toner cartridge include a convex portion and a conveyance drive gear. There is a protrusion which protrudes from the center of the conveyance drive gear. Further, there is a hole at a rear side of the convex portion. The protrusion is to be inserted into the hole which is at the rear side of the convex portion.

A developing unit includes a body and a displacement member. The displacement member is to be held by the body in a first mode in a first mounting state, and is to be held by the body displaceably between the first mode and a second mode in a reversible fashion in a second mounting state. The first mounting state is a state in which a first toner cartridge is mounted on the developing unit. The second mounting state is a state in which a second toner cartridge is mounted on the developing unit.

A developer cartridge may include: a first gear having a small-diameter gear portion and a large-diameter gear portion; and a second gear including: a first columnar portion centered on a second axis; a second columnar portion having a smaller diameter than the first columnar portion; a first engagement portion extending along a portion of a peripheral surface of the first columnar portion and engageable with the small-diameter gear portion; a second engagement portion extending along a portion of a peripheral surface of the second columnar portion and positioned closer to a housing than the first engagement portion in an axial direction and engageable with the large-diameter gear portion; and a protruding portion protruding in the axial direction and rotatable together with the first engagement portion and the second engagement portion. The second engagement portion may engage the large-diameter gear portion after the first engagement portion engages the small-diameter gear portion.

An image forming unit has a configuration in which, when an opening-closing member causes respective first openings to be opened by the engagement of the opening-closing member and an engaging section in association with an operation of attaching a developer container to an attachment unit, a first surface and a second surface are separated away from each other until arrival of the first openings at positions corresponding to respective second openings, and the first surface and the second surface are brought into proximity to each other upon the arrival of the first openings at the positions corresponding to the respective second openings.

An image forming apparatus includes lock mechanisms, a second detection processing portion, and a second release processing portion. The lock mechanisms regulate attachment and detachment of the developer storage portions attached to the attachment portions. The second detection processing portion detects whether or not any of the image forming units has an abnormality. The second release processing portion can release a regulation on attachment and detachment of two or more developer storage portions corresponding to two or more image forming units that include at least an image forming unit adjacent to the image forming unit detected to have the abnormality.

In a toner conveying device, a conveyance path of toner is formed in the casing. A conveyance screw is supported by two support portions of the casing so as to be rotated in the conveyance path and convey the toner along the conveyance path. A low friction portion is provided on an inner side surface of the casing facing the conveyance screw, in a middle of the two support portions. The low friction portion has a lower friction coefficient with the conveyance screw than the other portions of the inner side surface. In a region along a longitudinal direction of the conveyance screw including the low friction portion, a space between the low friction portion and the conveyance screw is narrower than a space between the conveyance screw and portions of the inner side surface other than the portion on which the low friction portion is provided.