Patent ID: 9618889
Date: 2017-04-11
CPC Classifications: G03G,H05B

Claim:
1. A fixing device configured to fix an image on a recording material by heating the recording material where the image is formed, comprising: a cylindrical rotary member including an electroconductive layer; a coil configured to form an alternating magnetic field which subjects the electroconductive layer to electromagnetic induction heating, the coil including a spiral shaped portion which is disposed in the rotary member so that a spiral axis of the spiral shaped portion extends along a generatrix direction of the rotary member; and a magnetic core configured to guide magnetic force lines of the alternating magnetic field, the core being disposed in the spiral shaped portion, the core having a shape where a loop is not formed outside the rotary member, wherein the electroconductive layer generates heat mainly by an induced current in the electroconductive layer, the induced current being induced by the magnetic force lines extending from one longitudinal end of the core, through an outside of the electroconductive layer, to the other longitudinal end of the core.