Process cartridge and electrophotographic image forming apparatus

摘要

An electrophotographic image forming apparatus for forming an image on a recording material includes an electrophotographic photosensitive drum; charging means for charging the photosensitive drum; developing means for developing a latent image formed on the photosensitive drum into a toner image; transfer means for transferring the toner image onto the recording material; fixing means for fixing the toner image on the recording material; a motor (161); a main assembly side gear (34) for receiving driving force from the motor; a recess formed (139A) substantially at a center of the gear, the recess having a polygonal cross-section; a projection (137A) provided at a longitudinal end of the photosensitive drum (107), wherein when the main assembly side gear (34) rotates with the recess (139A) and projection (137A) engaged with each other, rotational driving force is transmitted from the gear to the photosensitive drum through the recess and the projection with the projection being pulled into the recess, wherein a free end (137A1) of the projection and a bottom surface (139A1) of the recess are contacted to each other so that the process cartridge is positioned in place in a longitudinal direction of the photosensitive drum relative to the main assembly; and moving means for imparting relative movement between the recess and the projection in a longitudinal direction of the photosensitive drum to engage the projection with the recess.