Patent ID: 8314372
Filing Date: 2012-11-20
Classification: H05B

Abstract:
1. An induction heater, comprising: a cylindrical heating roller that performs electromagnetic induction heating; an exciting coil that heats the heating roller; a degaussing coil that is made so as to become shorter than the exciting coil in an axial direction of the heating roller and that decreases magnetic fields of the exciting coil; and magnetic members that are made of a magnetic material and that guide magnetic fluxes of the exciting coil and/or magnetic fluxes of the degaussing coil, thereby making up a magnetic circuit between the magnetic members and the heating roller, wherein the exciting coil has parallel portions extending in parallel with the axial direction of the heating roller and two turn portions provided at both ends of the parallel portions; the degaussing coil has parallel portions extending in parallel with the axial direction of the heating roller and two turn portions provided at both ends of the parallel portions; the exciting coil and the degaussing coil include a common structure that is adapted to overlay one of the two turn portions and the parallel portions of the exciting coil on one of the two turn portions and the parallel portions of the degaussing coil; and the magnetic members comprise a plate-like conveyance-direction-oriented core aligned along a circumferential direction orthogonal to the axial direction of the heating roller so as to straddle the longitudinal direction of the exciting coil, and a plate-like axial direction core aligned to the axial direction of the heating roller and placed in a direction orthogonal to the plate-like conveyance-direction-oriented core so as to straddle only a lateral portion of the degaussing coil at an other one of the two turn portions.