Patent ID: 8644722

Claim:
A fixing device, comprising: a fixing unit for fixing a toner image to a recording sheet by heat; a magnetic flux generator including a switching element for switching a current for generating a magnetic flux to cause heat generation of the fixing unit and adapted to generate a magnetic flux for causing heat generation of the fixing unit; a temperature detector for detecting the temperature of the switching element; and a control unit for performing a start-up mode for raising the temperature of the fixing unit to a fixing temperature suitable for fixing the toner image to the recording sheet by starting heat generation of the fixing unit by the magnetic flux generated by the magnetic flux generator and a steady mode for controlling heat generation of the fixing unit so that the temperature of the fixing unit is maintained at the fixing temperature after the temperature of the fixing unit reaches the fixing temperature, wherein the control unit: turns off the switching element when the temperature of the switching element detected by the temperature detector is equal to or higher than a first reference temperature lower than a destruction temperature at which the switching element may be destroyed during a period of the start-up mode, and turns off the switching element when the temperature of the switching element detected by the temperature detector is equal to or higher than a second reference temperature lower than the destruction temperature and higher than the first reference temperature during a period of the steady mode.