PURPOSE: To prevent an increase in the cost of the device and the occurrence of vibrations by transmitting a driving force from a driving source to rotary members by means of wire ropes.

CONSTITUTION: A drive motor 4 is disposed in the middle, and a motor pulley 5 is provided on the shaft of the drive motor 4. A pulley 2 is fixed to the shaft of each photosensitive drum 1, and the wire rope 3 is wound round each pulley 2 and the motor pulley 5. Each photosensitive. drum 1 rotates by transmitting a driving force from the drive motor 4 to each pulley 2 via the motor pulley 5. That is, each two photosensitive drums 1 are connected by the wire rope 3 and rotate integrally. Therefore, the driving force is smoothly transmitted without the occurrence of vibrations due to the driving of a gear, belt, etc., and the occurrence of rotation irregularities, etc., due to eccentricity. Also, because the cost of components is reduced, the cost of the device can be reduced.