US Patent 7391999 Developer supply container and coupling member used therefor

A coupling member to be engaged by snap hooking with an engaging hole provided to a driving portion of a main assembly of an image forming apparatus is provided with a snap hook portion at an entire peripheral surface thereof so as to prevent idle running at the time of start of rotation of the driving portion to obviate an impingement shock when the coupling member is caused to impinges on a rib provided to the driving portion.