Patent ID: 8463170

Claim:
An image forming apparatus comprising: an image forming section for forming a toner image and transferring the toner image to a sheet; and a fixing device including a heating member and a pressing member and fixing the toner image to the sheet by conveying the sheet while holding the sheet between the heating member and the pressing member, wherein the fixing device includes: a coil arranged along the outer surface of the heating member for generating a magnetic field; a magnetic core arranged at a side of the coil opposite to the heating member and forming a magnetic path together with the heating member, the magnetic path being composed of a first path for induction-heating a specified area of the heating member and a second path for induction-heating only a smaller area as a reduction of the specified area and the magnetic field being composed of a common magnetic field region where both the first and the second paths pass and an uncommon magnetic field region where only the first path passes; a path switching member for switching the magnetic path between the first path and the second path; and a magnetism adjusting member separate from the path switching member and arranged at least over the uncommon magnetic field region with a clearance between the magnetism adjusting member and the path switching member, the magnetism adjusting member permitting the passage of magnetic fluxes propagating toward the heating member from the magnetic core in the uncommon magnetic field region when the magnetic path is switched to the first path by the path switching member while suppressing the passage of the magnetic fluxes in the uncommon magnetic field region when the magnetic path is switched to the second path by the path switching member.