Heating device and fixing apparatus having the same

摘要

A heating device suitable for use in an image forming apparatus and a fixing apparatus having the same. The heating device comprises heating roller having a double-layered structure of a magnetic layer and a non-magnetic layer; a heat generation unit installed on the inner peripheral surface of the heating roller; a first insulation layer for insulating the heating roller and the heat generation unit; an internal tube installed on the inner peripheral surface of the heat generation unit so that the heat generation unit can be tightly contacted with the heating roller; and a second insulation layer for insulating the heat generation unit and the internal tube. The heating device can make the temperature of the heating roller equalized and maximize the power efficiency because the heating roller has a double-layered structure of a magnetic layer and a non-magnetic layer and the heat generation unit is tightly contacted with the heating roller. The inventive fixing apparatus is provided with such a heating device.