Patent ID: 7970315

Claim:
A developing cartridge comprising: an input gear which receives an external driving force; a developing roller which carries developer; a supply roller that is in contact with the developing roller and supplies the developer to the developing roller; a supply roller gear that is meshed with the input gear to drive the supply roller using 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 comprising a partition wall that partitions an 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; an idle gear that is meshed with the supply roller gear and the developing roller gear and transmits the driving force from the supply roller gear to the developing roller gear; a reinforcing plate provided in the housing to bear the supply roller; and a contact part provided in the housing to make contact with the reinforcing plate from a downstream side in an action direction of a resultant force generated by the combination of a pressing force of a tooth flank of the input gear on the tooth flank of the supply roller gear and a reaction pressing force of the tooth flank of the idle gear on the tooth flank of the supply roller gear, wherein the input gear and the partition wall overlap each other as viewed from a side of the developing cartridge.