| 摘要 |
PROBLEM TO BE SOLVED: To provide a temperature controller equipped with an inexpensive second safety circuit that detects abnormality of a CPU and maintains an off-state of a fixing heater in addition to a safety circuit by hardware in which a CPU is not interposed. SOLUTION: The temperature controller 9 is equipped with: a temperature detection part 23 that detects fixing temperature; the CPU 41 that outputs a heater control signal HC for driving and controlling the fixing heater 21 so that the fixing temperature may be target temperature; the safety circuit 304 that forcibly stops power supply to the fixing heater 21; a pulse generation circuit 45 that generates an edge signal ES from a pulse signal SLCT in a predetermined cycle output by the CPU 41; a timer circuit 49 that outputs a forcible stop signal FS when predetermined time elapses after output voltage from the pulse generation circuit 45 is input; and a gate circuit that turns off the fixing heater 21 according to the output signal from the timer circuit 49 or the heater control signal HC. The one cycle of the pulse signal is set to be shorter than the predetermined time. COPYRIGHT: (C)2009,JPO&INPIT
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