| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixing device for preventing useless thermal conduction from a nip part to the other parts of a heat roller, raising temperature of the nip part of the heat roller up to predetermined temperature quickly, and heating only the nip part of the heat roller required for fixing operation in a concentrated manner to improve thermal efficiency of a heater. SOLUTION: The heater is arranged inside a roller core of the heat roller. The roller core is composed of a main tube part constituting the nip part and supporting tube parts on both sides of the main tube part. Heat insulating parts for preventing thermal conduction from the main tube part to the supporting tube parts are provided in parts adjacent to the main tube part and the supporting tube parts. A plurality of heat insulating holes are formed in the peripheral direction of a cylindrical wall of the heat insulating parts and cross sectional area of the heat insulating parts is set to be smaller than cross sectional area of the main tube part to prevent useless thermal conduction from the main tube part to the supporting tube parts by the heat insulating parts. COPYRIGHT: (C)2009,JPO&INPIT
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