| 摘要 |
PROBLEM TO BE SOLVED: To suppress an excessive temperature rise compared with before without excessively increasing the area of a shield plate, and to prevent an effect of the shield plate as much as possible when the shield plate is retreated in an IH type fixing unit. SOLUTION: This fixing unit 14 of an image forming apparatus includes: an induced heating coil 52 for generating a magnetic field for induced-heating a heating belt 48; an arch core 54 and a side core 56 which form a magnetic path in the periphery thereof; a center core 58 for switching a shield member 60 between a shield position and a retreat position in a non-paper passing area of the heating belt 48; and a ring-shaped magnetism adjusting member 90 installed between the induced heating coil 52 and the heating belt 48. The magnetism adjusting member 90 shields magnetism with the shield member 60 without generating an induced current by a magnetic field when the shield member 60 is located in the retreat position, while generating an induced current when the shield member 60 is located in the shield position. COPYRIGHT: (C)2009,JPO&INPIT
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