Photosensitive drum assembly and process cartridge having the same

A process cartridge comprising a photosensitive drum assembly that is combinable with a driving shaft comprising a twisted hole with a non-circular cross-section having a plurality of corners, the process cartridge being combined with a main body of an image forming apparatus to be attachable to or detachable from the main body of the image forming apparatus, the process cartridge comprising:

• a toner storing container in which toner is stored;
• and
• a photosensitive drum assembly to which the toner is supplied from the toner storing container and which prints an image on a recording medium,
• wherein the photosensitive drum assembly comprises:
• a support disposed at one side of the photosensitive drum;
• an insertion body disposed at one side of the support and comprising a plurality of protrusions that are capable of being inserted in the twisted hole,
• wherein at least portions of each of the plurality of protrusions based on a cross-section of each protrusion that is perpendicular to the driving shaft, closely contacts two side surfaces of the twisted hole that constitute one of the plurality of corners of the twisted hole, respectively;
• and
• wherein each protrusion comprises a plurality of regularly-arranged concavo-convext portions formed in portions corresponding to two side surfaces that constitute one of the plurality of corners of the twisted hole.