Fixing device using an induction heating unit

摘要

A fixing device of the present invention includes a first roller that is made of a conductive material, and is rotated and driven; a second roller that is in contact with the first roller in the pressed state; and an induction heating unit that is arranged at the first roller side and concentrates the induction heating to the nip portion of the first roller and change a developer image formed on a fixing medium to a fixed imaged. This induction heating unit of the fixing device is made of a high permeable material, has a core that is open at the surface opposite to the first roller and a coil wound round the core and generates magnetic flux on the core when high frequency current is supplied to the core and has a high projecting portion so that a part of the core closes the first roller.