| 摘要 |
PROBLEM TO BE SOLVED: To prevent, even when an area where a recording medium does not pass through a nip part changes according to the size of the recording medium, an excessive increase in temperature of a fixing belt in the area and prevent a surface temperature of a heat source body from being excessively high in the area.SOLUTION: A fixing device includes, inside a fixing belt 25, a shutter member 51 that rotates on the same rotation shaft as a rotation shaft of the fixing belt 25, and shields, through the rotation of the shutter member 51, a part of a halogen heater 28 that is opposite to a heating area and corresponds to a first selection area through which A4 paper passes and B5 paper and A5 paper do not pass, and a part of the halogen heater 28 that is opposite to the heating area and corresponds to a second selection area through which A4 paper and B5 paper pass and A5 paper does not pass, appropriately according to the size of paper on which printing is performed. The shutter member 51 includes a shielding plate 52 that has a through hole 55 formed therein to maintain the surface temperature of a shielded part of the halogen heater 28 to be its critical temperature or lower.SELECTED DRAWING: Figure 3 |
