| 摘要 |
PURPOSE:To decide whether heaters are abnormal or not in accordance with easy procedures by detecting the temperature at a preliminarily determined time period and comparing the difference between detected temperatures with a prescribed value. CONSTITUTION:A controller which controls the temperature of a fixing device is provided with a microprocessor MPU, a read/write memory RAM, a read-only memory ROM, an I/O port IOP, an A/D converter ADC, etc., and heaters HT1 and HT2 are controlled through triacs 21 and 22 and photocouplers 18 and 44 by the output from the IO port IOP. Temperatures of heaters HT1 and HT2 are detected by a thermistor TH and are inputted to the microprocessor MPU through the A/D converter ADC and the I/O port IOP. The microprocessor MPU compares the difference between temperatures, which are detected at a preliminarily determined time period, with a prescribed value to detect abnormality of heaters HT1 and HT2. |
