| 摘要 |
In a widthwise direction of a heating roller perpendicular to a sheet conveyance direction, an amount of magnetic flux acting on the heating roller in the neighborhood of an end portion of the heating roller is larger than that at a center portion of the eating roller, so that it is possible to prevent a lowering in temperature at the heating roller end portion. Further, in a temperature range in which a temperature of the heating roller is higher than a fixation temperature and is lower than a heat-resistant temperature of a heating apparatus, the heating roller has a temperature area in which a resistance thereof is lowered, so that it is possible to reduce temperature rise in a differential area between a large-sized sheet passing area and a small-sized sheet passing area when a sheet having a size smaller than a maximum size (non-sheet passing portion temperature rise). |
