| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus capable of efficiently preventing generation of paper wrinkles and gloss unevenness. <P>SOLUTION: The fixing device employs a belt-nip system, in which a separation roller disposed on a downstream side of a nip and pressing a stretched fixing belt from an inner side of the belt is in a multi-step crown shape having an increased diameter from each end toward the center. More particularly, the separation roller comprises: a center portion having a shape obtained by rotating a first hyperbola around an axis, the first hyperbola having a first crown amount with the center in the axial direction as a vertex; end portions having a shape obtained by rotating a second hyperbola around the axis, the second hyperbola having a second crown amount equal to or smaller than the first crown amount, with the center in the axial direction as a vertex; and intermediate portions having a shape obtained by rotating a connecting line connecting the first hyperbola and the second hyperbola around the axis. The average slope angle of the intermediate portions is larger than the average slope angles of the center portion and the end portions. <P>COPYRIGHT: (C)2012,JPO&INPIT |
