jam occurs the flywheel is released and then the fuser motor 90 is stopped electric power supply to the fuser motor is stopped so as to avoid damage of the body by reducing an inertial force and the time until the fixing roller stops if the flywheel is released at the same time the fuser motor is stopped the stop time can be further reduced effectively according to the embodiment the revolving speed the number of revolution per unit time of the fuser motor 90 dc motor is detected by the revolving speed detector fig1 and the body controller cpu controls drive of the fuser motor in accordance with the detected revolving speed if the detected revolving speed of the fuser motor varies from a predetermined speed the controller determines that an abnormal situation occurs in the fuser motor so as to produce an error signal and to display error occurrence on the display of the operation unit at this time a stop signal is produced together with the error signal so as to forcedly stop the fuser motor the error signal may be sent to a personal computer network connected to the image forming apparatus with an lan cable so as to display the fuser motor error on a monitor of the personal computer during operation of the magnetic clutch i e when the flywheel is connected and released by ignoring the signal.