| 摘要 |
PURPOSE:To inform an abnormal state to a user to prevent the occurrence of troubles by measuring the elapsed time after a switching temperature at which power supply to a heat source is stopped is detected and generating an abnormality signal if this measured time exceeds a prescribed time. 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 103 at a power-on time to change the switching temperature of the halogen heater H1. If an abnormal rise of the temperature of the inside of a fixing device is detected by the thermistor 103 after power supply of every other cycle is started, time counting of a timer is started simultaneously with stop of power supply, and abnormality detection is executed. If no abnormalities are detected at all during the time of this timer, the fall of the temperature of the fixing device 10 is detected by the thermistor 103 to start power supply. |
