An example image forming apparatus includes a main body, a driving motor rotatable in a first direction to provide a driving force to a developing cartridge and rotatable in a second direction opposite to the first direction, and a support assembly to, based on the developing cartridge being mounted to the main body, provide the driving force of the driving motor in the first direction to the mounted developing cartridge, and detach the mounted developing cartridge from the main body using the driving force of the driving motor in the second direction.

A toner cartridge includes a casing, a feeding member and a pump. the casing includes a toner accommodation chamber accommodating toner, and a toner discharging chamber having a discharge opening for discharging the toner, and a communication port for fluid communication between the toner accommodation chamber and the toner discharging chamber. A part of the feeding member is provided inside the communication port. When a minimum cross-sectional area of the communication port in a plane perpendicular to a toner feeding direction of the feeding member is Asmin, the toner discharging chamber has a cross-sectional area Bs larger than Asmin, and the toner accommodation chamber has a cross-sectional area Cs larger than Asmin.

A driving force transmission device includes a drive gear, a driven gear, which includes a gear portion and a partially toothless gear portion, rotates by the gear portion meshing with the drive gear, stops rotating in response to the partially toothless gear portion facing the drive gear, a first cam member and a second cam member which operate in conjunction with the driven gear, a first elastic member for urging the first cam member, a follower member to which urging force is applied by a second elastic member and which is moved by the second cam member, and a contact portion for coming into contact with the first cam member by urging force of the first elastic member. The first cam member includes a home cam surface for coming into contact with the contact portion so that rotation of the driven gear is limited.

A developing cartridge, to be used in an image forming apparatus in which the developing cartridge including a developer carrier and a drum cartridge including a photosensitive drum are attachable and detachable, includes a cartridge body including the developer carrier, first and second supporting members that support the cartridge body to be capable of turning, and a restricting member that restricts the turn of the cartridge body with respect to the first supporting member in the developing cartridge in which the first and second supporting members have been positioned in the body of the image forming apparatus and urging has been made possible in one direction in a turning direction of the cartridge body so that the developing roller is made capable of coming into contact with the photosensitive drum, when the developing cartridge has been attached to the image forming apparatus.

A second unit includes a restricted portion that comes into contact with a restricting portion provided to a body of an apparatus, the restricted portion coming into contact with the restricting portion, in order to restrict the movement of a developer carrier in a direction to make contact with an image carrier, when a developing cartridge has not reached a predetermined attachment position, and not coming into contact with the restricting portion when the developing cartridge is in the predetermined attachment position.

Disclosed is a developing apparatus including: a developer bearing member that bears a developer; a developing frame body that rotatably supports the developer bearing member; a one-end side end member that supports one-end side in an axis direction of the developer bearing member of the developing frame body; and another-end side end member that supports the other-end side in the axis direction of the developer bearing member of the developing frame body. Each of the one-end side end member and the other-end side end member is independently movable with respect to the developing frame body.

A drive transmission device includes: a first rotating member that rotates with driving power received from a driving source, a second rotating member that rotates with driving power from the first rotating member, and a driving-side engagement member and a driven-side engagement member for transmitting the driving power of the first rotating member to the second rotating member, wherein the driving-side engagement member and the driven-side engagement member engage with each other in a state in which the first rotating member is rotating whereby a power applying portion and a power receiving portion engage with each other while resisting against a second biasing power.

A developing device to prevent damage of a memory unit and poor connection between terminals of the memory unit and a main body of an image forming apparatus, by improving a mounting position of the memory unit. The developing device is removably mounted to a main body of the image forming apparatus. The memory unit includes terminals exposed through a rear side of the developing device. The memory unit is disposed closer to a power reception unit formed at one side of the developing device than to a driving force reception unit formed at an other side of the developing device.

The present invention relates to a rotational force driving assembly and a process cartridge used for being engaged with a rotational force driving head inside an electrophotographic image forming device. The rotational force driving assembly can comprise a hub, a rotational force receiving component, a side plate, and an axis offset adjusting mechanism. When the axis offset adjusting mechanism is not subjected to external force, the axis offset adjusting mechanism enables the axis of the rotational force receiving component to be parallel and offset to the axis of the hub. When the axis offset adjusting mechanism is subjected to external force, the rotational force receiving component extends out to be engaged with the rotational force driving head.

A power transmission apparatus includes a drive gear disposed on a shaft of a motor; a plurality of driven gears disposed to be engaged with the drive gear; and a plurality of driven members configured to receive power from each of the plurality of driven gears, wherein the plurality of driven gears is arranged so that, when the plurality of driven gears are engaged with the drive gear, a gear engagement phase of each of the plurality of driven gears is different.