| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus mounted with a fixing device designed such that a transfer material is restrained from being wrapped round an external pressure roller or a fixing belt and, as a result, a curl is corrected and steadily recovered by preventing the curl from becoming large during transfer and eliminating the need to add a curl correcting means such as a decurler. SOLUTION: The image forming apparatus includes a belt fixing device which has an endless fixing belt wound around a support pressure roller and a heating roller with a space in-between and the external pressure roller disposed opposite to the support pressure roller via the fixing belt, and which fixes an unfixed image on the transfer material while holding the transfer material between the external pressure roller and the fixing belt. The image forming apparatus is provided with a separating auxiliary means having a separation pawl disposed close to or in contact with the surface of the external pressure roller. A stable curled state is retained by a relational expression of time and a distance between the tip position of separation claw on the upstream side in the transfer material conveyance direction and the position of an exit on the downstream end of an area where the external pressure roller and the fixing belt hold the transfer material in a nipped state in the direction of the transfer material conveyance. COPYRIGHT: (C)2006,JPO&NCIPI
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