IMAGE FIXING DEVICE WITH AN INDUCTION COIL AROUND A HEATING ROLLER
摘要
<p>A fixing device is formed by using a heat generating roller having a sleeve of magnetic metal and a magnetizing coil (170) opposed to the outer peripheral of the heat generating roller and generating heat on the heat generating roller by an electromagnetic induction. The magnetizing coil may be formed by 60 copper wires bundled together whose surfaces are insulated and have the outside diameter of 0. 2 mm are drawn in the direction of rotation axis of the heat generating roller. The coil is wound around an ouiter circumference of the heat generating roller so that the bundles of wires in axial direction mutually come into close contact along the circumference of the heat generating roller to cover the upper half of the heat generating roller. Further, there may be many cores (240) arranged obliquely around the coil to heat uniformly along the axial direction of the heating roller by providing on average in any cross section the same magnetic flux density. Also, the coil (170) may extend in axial direction beyond the roller, to limit magnetic field variations resulting from marginal effects at the longitudinal ends of the coil.</p>
