| 摘要 |
PURPOSE:To improve the safety and reliability of a device by providing, independently of a heating member, a heater for preheating a safety device, thereby securely preventing overheat runaway without a time lag when the heating member overheats. CONSTITUTION:When a print signal is not given, a changeover switch 38 is kept in a first changeover condition, and consequently a power supply circuit for the main heater 11 opens without the main heater 11 being heated; however, a power supply circuit for an auxiliary heater 27 opens and the auxiliary heater 27 is kept heated, and by the heat a temperature fuse 26 serving as the safety device is kept preheated at a temperature of 40-60 deg.C. Because the changeover switch 38 is kept in a second changeover condition by the detection of the print signal, the power supply circuit for the auxiliary heater 27 opens, and the power supply circuit for the main heater 11 opens. Thus, the power is supplied to the energizing/heating resistor of the main heater 11 to be heated, so that the temperature of the main heater 11 is risen. |
