Patent ID: 8718506

Claim:
A fixing device comprising: a fixing rotary body including a first heat generation layer; a pressing rotary body disposed parallel to and pressed against the fixing rotary body to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed; a heat generator to heat the fixing rotary body, disposed opposite the fixing rotary body and including a second heat generation layer; an exciting coil to generate a magnetic flux, disposed opposite the heat generator via the fixing rotary body; a first alternating electric current power supply connectable to the exciting coil to output a first alternating electric current having a first frequency that causes the magnetic flux generated by the exciting coil to reach the first heat generation layer of the fixing rotary body; a second alternating electric current power supply connectable to the exciting coil to output a second alternating electric current having a second frequency that is lower than the first frequency and causes the magnetic flux generated by the exciting coil to reach the first heat generation layer of the fixing rotary body and the second heat generation layer of the heat generator; and a switch circuit connected to the exciting coil, the first alternating electric current power supply, and the second alternating electric current power supply to selectively connect the first alternating electric current power supply or the second alternating electric current power supply to the exciting coil.