PURPOSE: To eliminate the accumulation of color slurring by minimizing the color slurring in the subscanning direction of an output image, in a transfer type color image forming device such as a color laser printer.

CONSTITUTION: A photosensitive drum 1 is driven by a dedicated motor 31, and simultaneously, a transfer drum 7 is driven by a dedicated motor 32. Then, a motor control circuit realizing the rotating/feeding mechanism for a motor so as to quickly set the phase difference of an FG signal in a prescribed range, even if the above-mentioned phase difference exceeds the prescribed range with respect to a phase comparative reference signal, is used for a photosensitive drum motor control circuit 35 controlling the speed of the motor 31 driving the photosensitive drum 1, and a transfer drum motor control circuit 36 controlling the speed of the motor 32 driving the transfer drum 7.