| 摘要 |
PROBLEM TO BE SOLVED: To obtain a switching system that abnormal heat of a heater is prevented especially at an early stage of impression with high reliability and it is used at both power supply voltage of 100 V and 200 V by connecting first and second heaters in serial or parallel according to AC power supply voltage to be impressed. SOLUTION: In switches 7, 9 to connect the first heater 2 with the second heater 3 in serial or parallel and the apparatus to switch the switches 7, 9 by detecting AC voltage to be impressed, the switches 7, 9 are separated from each heater in a state in which no AC voltage is impressed. Thus, since no current is supplied to each heater at the early stage of conduction of the AC power supply voltage, the abnormal heat of the heater and discontinuity caused when power supply voltage incompatible to a connection state of the heaters is impressed are prevented. |
