| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fixing device of electromagnetic induction heat system, which can prevent excessive temperature rise of a fixing roller and degradation of fixability. Ž<P>SOLUTION: The fixing roller 101 has an electromagnetic induction heat generating layer 115 formed across a heat insulating layer 112 formed around a core bar 111 and across a magnetic adjusting alloy layer 114 that changes into a non-magnetic body when a temperature becomes a Curie temperature or higher. Near the fixing roller, an excitation coil 131 is disposed so as to extend in the direction of a roller shaft. In addition, demagnetization coils 136 and 137 are disposed at both ends of the excitation coil 131 in the extension direction of the coil 131. When the roller temperature in a paper non-passage area P2, through which paper of small size does not pass in the axial direction of the fixing roller 101, increases during printing on this paper, the demagnetization coils 136 and 137 generate a magnetic flux G2 for demagnetization and a magnetic flux G3 by the magnetization adjustment action of the magnetization adjustment alloy layer 114 based on its change to a nonmagnetic body. Thereby a magnetic flux G1 generated by the excitation coil 131 passing through the area P2 is canceled. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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