A rotary member has a plurality of loading sections each of which is adapted to accommodate a developing device operable to develop an electrostatic latent image formed on an image carrier. The rotary member is rotatable between a plurality of stop positions. A motor is operable to exert a torque on the rotary member, the torque including a first torque, a second torque lower than the first torque, and a third torque lower than the second torque. A controller is operable to cause the motor to exert the first torque to rotate the rotary member, and to cause the motor to interchange the torque between the second torque and the third torque to retain the rotary member at one of the stop positions.