| 摘要 |
PROBLEM TO BE SOLVED: To properly secure a printing speed in continuous printing in an image forming apparatus, having an excessive temperature rise preventing function for a heat roller. SOLUTION: Heat radiation rollers 22, each including a coil 34 made of bidirectional shape memory alloy, are disposed near both the end parts of the heat roller 20. When both the end parts of the heat roller 20 enter overheating states and ambient temperature rises above the transformation start temperature of the shape memory alloy, the coils 34 deform, increasing in diameter to be in attitudes of contacting an outer peripheral surface of the heat roller 20. Consequently, the surface heat of the heat roller 20 is conducted to the heat radiation rollers 22, and the surface of the heat roller 20 can be cooled at both the ends, so non-paper-passage areas at both the end parts of the heat roller 20 can surely be prevented from entering an abnormally high temperature states during continuous printing operation etc., for a narrow-width recording form P. COPYRIGHT: (C)2008,JPO&INPIT
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