Fixing Device Heat Conduction Overlap for Heating Time
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Solution Overview
Problem
In fixing devices, the excessive temperature rise in non-sheet-passing areas due to uneven heat distribution leads to longer heating times for the contact portion, especially when the length of overlap between the high-thermal-conductivity portion and the heat generator is equal between the width-direction end and central portions.
Innovation Solution
A fixing device design where the high-thermal-conductivity portion overlaps the heat generator for a shorter length in the width-direction central portion than in the end portions, allowing more direct heat conduction to the fixing belt, reducing temperature nonuniformity and heating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the length of overlap between the high-thermal-conductivity portion and the heat generator is equal between width-direction end portions and central portion, then the thermal conductivity is uniformly distributed, but the heating time becomes excessively long
Solution Approach 1:
The patent applies local quality by making the overlap length between the high-thermal-conductivity portion and heat generator different in different width-direction regions. Specifically, the overlap length in the width-direction central portion is made shorter than in the end portions, allowing localized optimization of heat conduction paths to reduce overall heating time while maintaining necessary thermal distribution.
Solution Approach 2:
The patent employs asymmetry by creating an asymmetric overlap configuration where the central portion has a different (shorter) overlap length compared to the end portions. This asymmetric design breaks the uniform distribution pattern and enables faster heating by creating more efficient heat conduction pathways in critical regions.
2Stability of the object's composition
If a high-thermal-conductivity portion is provided over the heat source, then temperature nonuniformity is suppressed, but the heating time increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying overlap lengths. The high-thermal-conductivity portion maintains temperature uniformity through strategic heat distribution, while the varying overlap lengths (shorter in center, longer at ends) optimize heating speed by creating preferential heat conduction paths without causing excessive temperature nonuniformity.
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 design reduces the time required to heat the contact portion to a predetermined temperature by prioritizing heat conduction to the fixing belt over the high-thermal-conductivity portion, minimizing temperature nonuniformity and ensuring consistent fixing performance.
Implementation Method 1
a high-thermal-conductivity portion provided on the opposite surface of the heat source and extending in the width direction such that at least a part of the high-thermal-conductivity portion overlaps the heat generator of the heat source, the high-thermal-conductivity portion having a higher thermal conductivity than at least one of materials forming the support portion and the contact portion
Data Source
AI summary
A fixing device includes a contact portion contacting a recording material transported; a heat source heating the contact portion and including a heat generator extending in a width direction intersecting a transport direction in which the recording material is transported, and a support portion supporting the heat generator, the heat source having a counter surface facing the contact portion, and an opposite surface; a high-thermal-conductivity portion is provided on the opposite surface of the heat source and extends in the width direction such that a part of the high-thermal-conductivity portion overlaps the heat generator of the heat source, the high-thermal-conductivity portion having a higher thermal conductivity than the support portion or the contact portion. A length of an area of overlap between the high-thermal-conductivity portion and the heat generator of the heat source in the transport direction is shorter in a width-direction central portion than in two width-direction end portions.