PURPOSE: To secure the safety, and to continue the use of an image forming device except the time when the repair is required actually, by stopping an operation of a driving system of the image forming device, when abnormal current has been detected by a prescribed number of the times within a prescribed time.

CONSTITUTION: A titled device is provided with a circuit 21 for detecting a fact that supply current to a scavenger roller 7 from a power source part 20 has become abnormal, and by its detecting output, the power source part 20 is controlled through a power source part controlling circuit 22. Also, by detecting output of the circuit 21, a copying machine driving system 24 is stopped through a driving system controlling circuit 23.