Induction heating roller unit, fixing device and image forming apparatus

摘要

To provide an induction heating roller unit that can efficiently supply power to a heating roller, and fixing device and image forming apparatus incorporating the same. The induction heating roller unit includes: a heating roller; and an induction coil having an outer diameter more than 0.7 times that of the heating roller, the heating roller being concentrically disposed outside said induction coil and generating heat by the effect of an induced current caused by a magnetic field produced by the induction coil. Since the ratio of the outer diameter of the induction coil to that of the heating roller is 0.7 or higher, power can be transferred from the induction coil to the heating roller with an extremely high efficiency.