| 摘要 |
PROBLEM TO BE SOLVED: To achieve reduction in a warm-up time and space saving while attaining lower heat capacity, by reducing the number of members arranged in a heating roller or the like in a fixing unit for an image forming apparatus. SOLUTION: The fixing unit 14 includes: an induction heating coil 52 arranged along an outer surface of a heating belt 48; arch cores 54 and side cores 56 forming magnetic paths on both sides of the center of the coil; a center core 58 arranged at the center of the coil; and cut-off portions 60 provided at both end positions of the center core 58. The center core 58 is rotated to switch the cut-off portion 60 to a resistance position where magnetic resistance increases and a retracted position where magnetic field is allowed to pass, so that it is possible to cope with a change of sheet size without increasing space. COPYRIGHT: (C)2010,JPO&INPIT
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