US Patent 7653329 Image forming device having variable pre-rotation cleaning process

An image forming device includes a motor, a photoconductive drum, a charging unit, an abrasion tool, a timer, and a controller. The charging unit is provided at a periphery of the photoconductive drum, and charges the photoconductive drum by a corona discharge method. The abrasion tool is provided at the periphery of the photoconductive drum, and abrades the surface of the photoconductive drum while the photoconductive drum is rotating. The timer measures a job interval from when the motor is stopped to end a previous print job until when the motor is driven to start a next print job. The controller executes over a predetermined period of time a pre-rotation process to adjust the photoconductive drum and a peripheral system of the photoconductive drum into an optimum state, and calculates a period when the pre-rotation process is to be executed according to the measured job interval.