Endless Belt Heating Member Longitudinal Heat Control
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Solution Overview
Problem
Existing image heating apparatuses face issues with durability due to heat transfer inefficiencies and abrasion between the fixing member and flange abutment surfaces, particularly when the heat transfer layer is longer than the pressure member, leading to temperature increases and reduced Young's modulus.
Innovation Solution
An image heating apparatus featuring an endless belt with a sheet-like heating member and regulating members to prevent longitudinal movement, where the heating member is fixed at one end and in contact with the belt's inner surface along a peripheral direction, with a heat transfer member to efficiently heat the belt, and both end portions of the heat transfer member are positioned outside the heating portion in the longitudinal direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat transfer layer is provided between the heating element and the fixing member to efficiently transfer heat, then thermal conductivity in the thickness direction increases, but thermal conductivity in the longitudinal direction also increases, causing temperature increase and Young's modulus drop
Solution Approach 1:
The heat transfer layer is designed with different thermal conductivity characteristics in different directions. The layer has high thermal conductivity in the thickness direction (perpendicular to the belt surface) to efficiently transfer heat from the heating element to the fixing member, while maintaining low thermal conductivity in the longitudinal direction (along the belt surface) to prevent heat propagation to the ends. This anisotropic heat transfer property resolves the contradiction by locally optimizing heat flow paths.
Solution Approach 2:
The heating system is segmented into distinct functional zones: a central heating zone where the heating element contacts the heat transfer layer, and end zones where heat transfer is minimized. The heat transfer layer acts as a thermal barrier at the ends, segmenting the thermal flow to prevent excessive temperature rise at the belt ends, thereby maintaining Young's modulus and preventing abrasion.
2Reliability
If the heat transfer layer is longer than the pressure member, then heat transfer to the pressure member is improved, but heat transfer to the pressure member drops in areas where the fixing member is not in contact, causing temperature increase and accelerated abrasion
Solution Approach 1:
The heat transfer layer's longitudinal thermal conductivity is selectively controlled: high in the central region where heat transfer to the pressure member is needed, and low at the ends where the fixing member contacts the flange abutment surface. This local differentiation prevents heat accumulation at the ends, avoiding temperature-induced abrasion while maintaining effective heating in the contact zone.
3Loss of energy
If the fixing member temperature increases, then heat transfer efficiency is improved, but Young's modulus drops, accelerating abrasion between the fixing member and flange abutment surface
Solution Approach 1:
The fixing member's thermal management is segmented into a heated zone (where temperature increase improves heat transfer efficiency) and a protected zone (where temperature is controlled to maintain strength). The heat transfer layer's directional conductivity creates this segmentation, allowing the central region to operate at higher temperatures for efficient heating while keeping the end regions cooler to preserve Young's modulus and prevent abrasion.
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 enhances durability by maintaining controlled temperature and reducing abrasion, allowing for continuous operation without belt failure, as demonstrated by successful testing with 150,000 sheets without belt detachment from flanges.
Implementation Method 1
a sheet-like heating member provided inside of the endless belt... to heat the endless belt
Implementation Method 2
The heating member includes a heat transfer member in contact with the inner surface of the endless belt, and a heating portion located on an opposite side from a side, of the heating member, in contact with the inner surface of the endless belt across the heat transfer member
Data Source
AI summary
An image heating apparatus includes an endless belt, a rotary member configured to form a nip portion with the endless belt, regulating members for regulating the endless belt from moving in a longitudinal direction by being in contact with longitudinal ends of the endless belt, and a sheet-like heating member. The heating member includes a heat transfer member in contact with the inner surface of the endless belt, and a heating portion located on an opposite side from a side, of the heating member, in contact with the inner surface of the endless belt across the heat transfer member. Both end portions of the heat transfer member are disposed at the same location or outside of both end portions of the heating portion in the longitudinal direction and are disposed inside of both end portions of the rotary member in the longitudinal direction.