Patent attributes
An electrophotography fixing device has a heating roller and an induction heating device. In order to improve heat resistance, heat radiating performance and insulation performance and in order to appropriately uniformly heat the heating roller, in the induction heating device, induction heating coils wound onto a core are fixed by varnish mixed with mica, and the outside surfaces thereof are fixed by a heat resistant bundling band or a molded body of a heat resistant material, or coated with a heat resistant, insulating and thermal conductive sheet. Alternatively, the same sheets as the above described sheet are provided between the core and the coils and between the layers of the coils. In addition, the core is formed with a hole extending in axial directions or holes extending in directions perpendicular to the axial directions. Moreover, the coils are doubly insulated.