| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a structure where installation space of a member provided for switching paper size is prevented from being increased imprudently and which hardly produces a magnetic shielding effect in a state where the member is retracted during induction heating in a fixing unit for an image forming apparatus. <P>SOLUTION: The fixing unit 14 includes an induction heating coil 52 arranged along an outer surface of a fixing roller 45, an arch core 54 composed of magnetic material so as to form a magnetic path around the induction heating coil 52, and a magnetic shielding member 60 made of non-magnetic metal formed in ring shape. When switching a position of the magnetic shielding member 60 to a retreat position (A), magnetism is allowed to pass and the induction heating is performed. When switching it to a shielding position (B), anti-magnetic field is generated by penetrating magnetic flux in the ring, so that the magnetism is intercepted and the induction heating is not performed. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
