PROCESS CARTRIDGE AND IMAGE FORMING APPARATUS

A developing unit is detachably mountable to a main assembly of an image forming apparatus, the developing unit comprising a rotatable developing roller, a rotatable developer supplying roller provided in contact with the developing roller and configured to supply a developer to the developing roller; a developer accommodating chamber configured to accommodate the developer; a developing chamber in which the developer supplying roller is provided; a rotatable feeding member provided in the developer accommodating chamber and configured to feed the developer from the developer accommodating chamber into the developing chamber by moving the developer upwardly against a gravity; and a driving force receiving portion configured to receive a driving force for rotating the developer supplying roller, the developing roller and the feeding member. The developing unit further comprises a first driving force transmitting portion provided on the developer supplying roller and configured to transmit the driving force received by the driving force receiving portion to the developing roller; and a second driving force transmitting portion provided on the developing roller and configured to transmit the driving force from the first driving force transmitting portion to the developing roller, wherein the driving force receiving portion is provided on the developer supplying roller, wherein the developer supplying roller and the developing roller are rotatable such that surfaces of the developer supplying roller and the developing roller move at a contact portion between the developer supplying roller and the developing roller n the same direction and toward a bottom of the developing chamber, and wherein a peripheral speed of the surface of the developer supplying roller is higher than that of the developing roller.