Fixing Device Holder Slits for Wax Drainage
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Solution Overview
Problem
The electromagnetic induction heating method in fixing devices for image forming apparatuses can result in wax from toner adhering to the recording medium, causing fixing failures due to wax accumulation and re-fusion on the induction heater and fixing members, which existing drainage passages and resin holders fail to effectively prevent.
Innovation Solution
The fixing device incorporates a holder with slits on its surface facing the heat generator, where a ferromagnetic core covers the open bottom of each slit, forming bottomed grooves that prevent wax from adhering and re-fusing by absorbing heat, thus preventing wax from adhering to the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electromagnetic induction heating method is used to heat the fixing member, then energy efficiency is improved and startup time is reduced, but wax from toner adheres to the induction heater and fixing members, causing fixing failures
Solution Approach 1:
The holder surface is segmented into multiple slits that extend in the rotation direction, dividing the continuous surface into separate drainage channels. This segmentation allows wax to be channeled and drained along the slits rather than accumulating on the holder surface, preventing re-fusion while maintaining the energy-efficient induction heating method.
Solution Approach 2:
The ferromagnetic core acts as an intermediary element by covering the bottom portions of the slits. This creates bottomed grooves that guide wax drainage while the ferromagnetic material itself does not readily adhere to wax, serving as a mediator between the holder and the wax to prevent harmful adhesion.
2Object-generated harmful factors
If drainage passages are provided on the holder surface, then wax drainage is improved, but the resin holder material allows wax to be easily fused again upon absorbing heat
Solution Approach 1:
The solution combines the resin holder material with ferromagnetic core material to create a composite structure. The ferromagnetic core covers the bottom portions of the slits, providing a material that does not easily re-fuse with wax, while the resin holder provides the structural framework and drainage passages. This composite approach leverages the advantages of both materials.
Solution Approach 2:
The ferromagnetic core serves as an intermediary material in the drainage passages, replacing the pure resin material at critical locations where wax contact occurs. This intermediary layer prevents direct contact between wax and the heat-absorbing resin, thereby preventing re-fusion while maintaining drainage functionality.
3Use of energy by moving object
If the induction heater is disposed facing the fixing member, then heating efficiency is improved, but wax accumulates on the holder surface and fills gaps between the induction heater and fixing member
Solution Approach 1:
The holder surface facing the fixing member is segmented into multiple slits that extend parallel to the rotation direction. This segmentation creates drainage channels that prevent wax accumulation on the holder surface, allowing wax to be channeled away before it can fill the gap between the induction heater and fixing member, thereby maintaining heating efficiency.
Solution Approach 2:
The slits extend in the rotation direction (circumferential dimension) rather than radially, creating a new dimensional approach to drainage. This orientation allows wax to be drained along the rotation direction, effectively removing it from the gap-filling path while maintaining the facing configuration for efficient heating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents wax from adhering to the recording medium during the fixing process by ensuring the wax is absorbed and does not re-fuse, thereby reducing fixing failures and maintaining image quality.
Implementation Method 1
a high-frequency alternating current supplied to the excitation coil forms an alternating magnetic field around the excitation coil, which generates eddy currents on a surface of the heating roller
Implementation Method 2
When the eddy currents are generated around the heating roller serving as a heat generator, the electrical resistance of the heating roller leads to Joule heating of the heating roller, thereby heating the fixing belt stretched over the heating roller
Data Source
AI summary
A fixing device includes a fixing member including a heat generator and an induction heater to heat the fixing member by electromagnetic induction. The induction heater includes an excitation coil, a ferromagnetic core to form a magnetic path to direct magnetic flux arising from the excitation coil to the fixing member, and a holder to hold the excitation coil and the ferromagnetic core. The holder has a surface facing the heat generator. The surface has a plurality of slits extending parallel to a direction of rotation of the fixing member. The ferromagnetic core is coupled to the holder and covers an open bottom portion of each slit of the plurality of slits to form a plurality of bottomed grooves.