Patent ID: 7330681

Claim:
A developing device attachable to and detachable from a body of an image forming apparatus, comprising: a developer bearing roller for bearing a developer; a first driving wheel that is provided on an end of said developer bearing roller and that is for driving said developer bearing roller; a second driving wheel that, in a state where said developing device is attached to the body of said image forming apparatus, receives a drive force from the body of said image forming apparatus and that transmits said drive force to said first driving wheel; and a positioning member that is made of metal and that is for positioning said first driving wheel and said second driving wheel, wherein said developing device has a third driving wheel that serves as a medium when said second driving wheel transmits said drive force to said first driving wheel; wherein, in a state where said developing device is attached to the body of said image forming apparatus, said second driving wheel receives said drive force from the body of said image forming apparatus and transmits said drive force to said first driving wheel via said third driving wheel; wherein said third driving wheel is positioned using said positioning member, wherein said first driving wheel, said second driving wheel, and said third driving wheel are a first driving gear wheel, a second driving gear wheel, and a third driving gear wheel, respectively; wherein said positioning member has a first supporting section for rotatably supporting said developer bearing roller, a second supporting section for rotatably supporting said second driving gear wheel, and a third supporting section for rotatably supporting said third driving gear wheel; wherein said second driving gear wheel supported by said second supporting section meshes with said third driving gear wheel supported by said third supporting section; and wherein said third driving gear wheel meshes with said first driving gear wheel that is provided on said developer bearing roller supported by said first supporting section.