US Patent 7483651 Drive device used in image forming device

A drive device 1 includes a motor 2, a planetary roller type power transmission unit and a drive control unit. The planetary roller type power transmission unit includes a plurality of planetary rollers 4, a ring 6, a fixed body 9 covering the ring 6 and having an aperture 9a located so that a projecting portion 6a is movable therein, a carrier roller 7, and an output shaft 8. A drive control unit 10 controls the rotation of a motor 2 of the drive device so that when the image forming device is not carrying out an image forming operation the projecting portion 6a of the ring 6 reciprocates within the aperture 9a of the fixed body 9.