the structure is simpler. Moreover, as the driving force receiver is detachably arranged at one end of the photosensitive drum, the photosensitive drum is convenient in maintenance. As different driving force receivers are used for different image forming devices but the main body, namely the photosensitive drum, is the same, users only need to replace the driving force receiver but not need to replace the photosensitive drum, thus the manufacturing cost and the use cost are reduced. However, due to the flexible pressure device, the driving force receiver, namely the driving force receiving opening, is always in the pressurized state when beginning to get engaged and disengaged with a driving mechanism of the image forming device, thus the driving force receiver and the driving member for the imageforming device cannot be kept in a straight line when beginning to get engaged and disengaged as the inner space of the image forming device is limited, consequently the driving force receiver and the driving member of the image forming device are inevitably subjected to the friction damage when meeting a bevel when beginning to get engaged and disengaged and then the engagement between the driving force receiver and the driving member of the image forming device is affected.