Patent ID: 9658584
Date: 2017-05-23
CPC Classifications: G03G

Claim:
1. A fixing apparatus for fixing a toner image on a recording material while conveying and heating, at a nip portion, the recoding material on which the toner image has been formed, the fixing apparatus comprising: a rotary member that includes a conductive layer; a helical coil provided inside the rotary member, a helical axis of the helical coil extending in a generatrix direction of the rotary member; a magnetic core provided inside the helical coil, the core having a shape that does not form a loop outside the conductive layer; and a back-up member that forms a nip portion together with the rotary member, wherein the conductive layer generates heat with an electric current flowing in the conductive layer, the electric current being induced by an alternating magnetic field generated by an electric current flowing in the helical coil, and wherein in the generatrix direction, when a winding pitch of the helical coil in a middle area, winding pitches in end-portion areas, and winding pitches in intermediate areas that are areas between the middle area and the end-portion areas are X, Y, and Z, respectively, then Y<X<Z is satisfied.