IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To provide an image forming device capable of maintaining a fixing force for inhibiting the movement of a movable-type developing device even in case stress is applied to the movable-type developing device by an operator. SOLUTION: Upon the output of a signal voltage E3 from a CPU 101, positive power sources are supplied to the coils of relays RY1, RY2, RY3, and RY4, so that the contacts of the relays are switched and short circuits are caused between the coils L1, L2, L3, and L4 of a revolver motor 113. When torque is applied to the drive shaft of the revolver motor 113 as by the hand of an operator and the weight of a revolver developing unit 20 itself after the short circuits, counter-electromotive forces occur in the coils L1, L2, L3, and L4. This counter-electromotive forces apply torque, being opposite in direction to the previously applied torque, to the drive shaft of the revolver motor 113. And this torque in the opposite direction pushes back the drive shaft of the revolver motor 113 toward the opposite direction and acts so as to inhibit the turn of the revolver developing unit 20.