Patent ID: 7199339

Claim:
A heating apparatus for heating a material to be heated by heat generated by induction heat generation member, comprising: magnet flux generating means; a holder for holding and fixing said magnetic flux generating means and having a coefficient β; an induction heating member which generates heat by electromagnetic induction heating by an action of magnetic flux generated by said magnetic flux generating means; and magnetic flux adjusting means for adjusting an area in which magnetic flux acts on said magnetic flux generating means in a longitudinal direction, of said induction heat generation member, perpendicular to a conveyance direction of a material to be heated; said magnetic flux adjusting means comprising a magnetic flux adjusting member, having a coefficient α, capable of coming into surface contact with said holder in the longitudinal direction of said induction heat generation member and moving means for moving said magnetic flux adjusting member by sliding said magnetic flux adjusting member on the surface of said holder; control means for controlling a length L (mm) of the sliding portion between said magnetic flux adjusting member and said holder in the longitudinal direction, according to the following relationship: −0.7≦(α−β) ×T×L≦ 0.7, wherein α represents a coefficient of linear expansion of said magnetic flux adjusting member; β represents a coefficient of linear expansion of said holder; T represents an increased temperature (° C.) of said holder from room temperature to a temperature during continuous use of said heating apparatus.