Patent ID: 7813673

Claim:
A developing cartridge comprising: an input gear to which a driving force is input from outside; a developing roller which carries developer; a supply roller, which is in contact with the developing roller, and which supplies the developer to the developing roller; a supply roller gear, which is meshed with the input gear, and which drives the supply roller with a driving force transmitted from the input gear; a developing roller gear that drives the developing roller with a driving force transmitted from the supply roller gear; a housing; a partition wall that partitions inside of the housing into a first chamber that accommodates the developer and a second chamber that houses the developing roller and the supply roller; a idle gear, which is meshed with the supply roller gear and the developing roller gear, and which transmits the driving force transmitted from the supply roller gear to the developing roller gear; a bearing, which is provided in the housing, and which supports the supply roller; and a contact part, which is provided in the housing, and which makes contact with the bearing from a downstream side in an action direction of a resultant force of a pressing force of a tooth flank of the input gear on a tooth flank of the supply roller gear and a reaction pressing force of a tooth flank of the idle gear on the tooth flank of the supply roller gear, wherein: when projected along a rotation axis of the developing roller, the input gear and the partition wall overlap each other; and the contact part comprises a shaft that supports the input gear and a shaft that supports the idle gear.