| 摘要 |
PURPOSE:To obtain a safety device easily controlled and with high precision by providing a feed voltage detecting means which detects a voltage supplied to a fixing heater, and a means which changes the fixing heater maximum energizing time of a feed time abnormality control means. CONSTITUTION:An insulating transformer 17 is provided to detect 8 commercial source voltage, and the voltage is decreased to the one fitted in a control means, and a control voltage proportional to the commercial source voltage is outputted. Such output is inputted to the feed voltage detecting means 16, and is converted to control output, and is inputted to the feed time abnormality control means 13. In other words, the output of the feed voltage detecting means 16 is inputted to the feed time abnormality control means 13 in addition to the temperature of a fixing roller and fixable setting temperature, and fixing heater maximum feed time is operated at a prescribed timing, and when a feed voltage increases over a reference value and the temperature of the fixing roller is increased abnormally. feed to the fixing heater 2 is cut off compulsorily, and also, when abnormality occurs in a thermistor, the temperature of the fixing roller is suppressed to a low level by accelerating a time to operate the safety device. |
