Asymmetric Demagnetizing Coil for Fixing Roller Heat Control

The demagnetizing coil is designed with an asymmetric shape where the overlapping width with the excitation coil varies along the axial direction. Specifically, the overlapping width is smaller at the end side (where recording paper does not pass) and larger at the center side (where recording paper passes). This asymmetric configuration allows the demagnetizing coil to reduce magnetic flux more strongly at the end region to prevent overheating, while maintaining sufficient magnetic flux at the center region to ensure proper heat generation for fixing, thereby resolving the contradiction between preventing overheating and maintaining fixing quality.

The demagnetizing coil implements local quality by having different overlapping widths with the excitation coil at different axial positions. The overlapping width is locally adjusted to be smaller at the end region and larger at the center region. This local variation in overlapping width creates corresponding local variations in demagnetizing effect, allowing the end region to have reduced heat generation (preventing overheating) while the center region maintains sufficient heat generation (ensuring proper fixing), thus resolving the contradiction between temperature control and operational stability.

The demagnetizing coil adopts an asymmetric shape with varying overlapping width along the axial direction, where the overlapping width transitions from smaller at the end side to larger at the center side. This asymmetric design provides adaptability to different paper sizes by creating a gradient demagnetizing effect that can accommodate variations in paper width without requiring complex adjustments or multiple coil configurations, thus resolving the contradiction between structural simplicity and adaptability.