Patent ID: 8923719

Claim:
A fixing device comprising: a fixing rotating body; a magnetizing coil disposed along a direction of a rotational axis of the fixing rotating body, and configured to heat the fixing rotating body by induction; a pressing member pressing against an outer circumferential surface of the fixing rotating body to form a fixing nip through which a recording sheet with an unfixed image formed thereon passes; a demagnetizing coil unit set including a pile of two or more demagnetizing coil units, each demagnetizing coil unit including a plurality of demagnetizing coils of different sizes, and being configured to cancel out part of magnetic flux generated by the magnetizing coil in a region corresponding to a non-sheet-passing region of the fixing rotating body; a sheet information acquisition unit configured to acquire sheet information including information relating to a width of the recording sheet; and an operation control unit configured to control an operation of each of the demagnetizing coils according to the width of the recording sheet, wherein in each demagnetizing coil unit, the demagnetizing coils are arranged such that a smaller demagnetizing coil is surrounded by a larger demagnetizing coil and that the demagnetizing coils are in a same plane extending along a surface of the magnetizing coil, and a combination of sizes of the demagnetizing coils differs among the demagnetizing coil units.