摘要 |
A switch control unit detects a power supply voltage of a heater detected by a voltage detection unit, and switch is performed on a load state of the heater in a range from a first load state to a fourth load state when the detected power supply voltage falls into a predetermined first domain. On the other hand, the switch is performed on the load state that ranges from the first load state to the third load state when the detected power supply voltage falls into a predetermined second domain that is higher in voltage than the first domain. That is, when the power supply voltage is in the second domain that is higher in voltage than the first domain, a limitation is imposed on the switch to the fourth load state where a combined resistance value is the lowest among the first and fourth load states. |