| 摘要 |
PURPOSE:To improve the safety and the fixability by detecting a rising variation of the detected temperature through two time counting means after a switching temperature from power supply to a heat source to stop of power supply is detected and generating an abnormality signal in accordance with detection results. CONSTITUTION:The state of power supply to a halogen heater H1 is switched from full-wave power supply to power supply of every other cycle in accordance with the detected temperature from a thermistor, which is detected at a power- on time, to make the switching temperature of the halogen heater H1 different. When it is detected by the thermistor 103 that the temperature of the inside of a fixing device exceeds a prescribed temperature after power supply of every other cycle is started, time counting is started in the first timer and the second timer simultaneously with stop of power supply, and abnormality detection is executed. If no abnormalities are detected as the result of comparison between detected temperature of these timers at respective count-up times, a fall of the temperature of the fixing device is detected by the thermistor 103 to start power supply. |
