| 摘要 |
PURPOSE: To clarify a failure spot and to allow quick determining so as to improve maintenance and a quality for a user by recognizing that a safety circuit operates independently from a system control section via a notifying means provided in the safety circuit. CONSTITUTION: A system control section 12 drives a heating control fixing roller, detects a temperature, etc., and outputs a pattern signal SG4 and a power conductive pattern generation section 14 drives and stops a heater 6 based on this signal SG4 and controls heating. When a voltage VT from a thermistor 3 provided on the surface of the fixing roller drops below a fixed value (when a surface temperature becomes an abnormal value Tb higher then an abnormal value Ta for control), a safety circuit 15 excites the relay 16 of a stransistor 18 and stops supplying of AC power to the heater 6. Then, the circuit 15 outputs a signal SG5 to the system control section 12 and notifies driving of the relay 16. Thus, when there is no increase ocurring in the temperature even after power is conducted to the heater 6, its cause is made clear. |
