| 摘要 |
PROBLEM TO BE SOLVED: To uniformize pressure on a sheet material in a fixing nip, thereby preventing increases in the temperatures of the edges of a thermal fixing roll and degradation in image quality by the temperature increases in the edges, and to prevent a decrease in productivity. SOLUTION: The fixing device includes the thermal fixing roll 1, a pressure roll 2 pressed against the thermal fixing roll 1, a heat-resistant belt 3 wrapped around the outer circumference of the pressure roll 2 and moved while held between the thermal fixing roll 1 and the pressure roll 2, and a belt stretch member 4 stretching the heat-resistant belt 3, and fixes an unfixed toner image 5a formed on the sheet material 5. The image forming apparatus is equipped with the fixing device. The belt stretch member 4 is disposed upstream of the pressure roll 2 and applies tension to the heat-resistant belt 3 between the pressure roll 2 and the heat-resistant belt 3, thereby wrapping the heat-resistant belt 3 along the thermal fixing roll 1 and forming the fixing nip. The belt stretch member 4 varies a gap between the thermal fixing roll 1 and the belt stretch member 4 in accordance with the thickness of the sheet material 5 entering the fixing nip. COPYRIGHT: (C)2005,JPO&NCIPI
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