| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixing device in which a temperature difference between the recording medium passage and non-passage areas of a fixing member is reduced. SOLUTION: The fixing device 100 includes: an excitation coil 110 that generates a magnetic field; a fixing roll 102 having a heat generation layer in which heat is generated by electromagnetic induction and a temperature sensitive layer 130 that has a magnetic permeability change starting point in a temperature area higher than set fixing temperature but lower than heat resistant temperature; and a pressure roll 104 deformed by its being firmly pressed against the peripheral face of the fixing roll 102. When the temperature exceeds the magnetic permeability change starting point 200°C in the paper non-passage areas B and D of the fixing roll 102 relative to recording paper P, the magnetism of the temperature sensitive layer 130 dissipates and also eddy current generated by electromagnetic induction decreases, and accordingly an amount of heat generated in the heat generation layer 128 decreases. This makes an offset phenomenon less likely to occur at the ends of a large-size recording paper even if this large-size one is fixed after the small-size one. COPYRIGHT: (C)2009,JPO&INPIT |
