| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus equipped with a watchdog circuit capable of detecting the abnormality of a CPU to thereby maintain the off-state of a fixing heater, without reducing cost performance. SOLUTION: The image forming apparatus 100 equipped with a control section 40 outputting a heater control signal and controlling the temperature of a fixing section 200 is further equipped with: the watchdog circuit 52 comprising a counter circuit to which flip-flop circuits 53 and 54 of a plurality of stages are cascade-connected; a zero cross circuit 39 for inputting a zero cross signal to the clock terminals of the respective flip-flop circuits 53 and 54; a clear signal generating circuit 55 for generating an edge signal when the logic of a pulse signal output to loads except the heater 20 from the control section 40 is switched and inputting the edge signal to the clear terminals of the flip-flop circuits 53 and 54; and a gate circuit 51 for turning off the heater control signal by the output signal of the watchdog circuit 52. COPYRIGHT: (C)2009,JPO&INPIT
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