US Patent 7466941 Drive device used in image forming device

A drive device 1 includes a planetary roller type power transmission unit, a temperature sensor 5b, a delay time determination unit 103, and an image processing control unit 104. The planetary roller type power transmission unit includes a plurality of planetary rollers at least a part thereof made from an elastic material that is pressed against the periphery of a motor 2 rotation shaft, a ring that contacts the plurality of planetary rollers, a carrier roller, and an output shaft. The temperature sensor 5b measures the temperature Te of or near the planetary roller. The delay time determination unit 103 determines the delay time Td from the start up time of the motor 2 until the start of the image forming process. The image processing control unit 104 starts the image forming process after the delay time Td has passed from the start up time of the motor 2.