Fixing Device Thermal Diffusion Layer Design
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Solution Overview
Problem
Existing image forming apparatuses face challenges in efficiently transmitting heat from a heater to a fixing belt for effective image fixation, leading to suboptimal fixing performance and potential uneven glossiness.
Innovation Solution
A fixing device comprising a belt member with a heater on its inner surface, a base layer, and an opposed layer that satisfies a specific thermal diffusivity ratio, ensuring efficient heat transmission to the fixing belt, thereby enhancing fixing performance and preventing uneven glossiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thermal diffusion member is used to transmit heat from the heater to the fixing belt, then heat transmission efficiency is improved, but the structure becomes more complex and manufacturing cost increases
Solution Approach 1:
The thermal diffusion member is segmented into a base layer and an opposed layer with different thermal diffusivities. The base layer (with higher thermal diffusivity) is positioned adjacent to the heater for efficient heat absorption, while the opposed layer (with lower thermal diffusivity) faces the fixing belt to control heat release. This segmentation allows optimization of heat transmission efficiency without requiring complex additional components.
Solution Approach 2:
The thermal diffusion member uses a composite structure combining materials with different thermal diffusivities. The base layer uses a material with high thermal diffusivity (e.g., metal) for rapid heat conduction from the heater, while the opposed layer uses a material with lower thermal diffusivity (e.g., resin or ceramic) to modulate heat transfer to the fixing belt. This composite approach achieves superior heat transmission efficiency while maintaining structural simplicity.
2Reliability
If heat is transmitted efficiently to the fixing belt, then fixing performance is improved, but uneven glossiness may occur due to non-uniform heat distribution
Solution Approach 1:
The thermal diffusion member exhibits local quality variations through its layered structure. The base layer with high thermal diffusivity ensures uniform heat distribution across the heater interface, while the opposed layer with lower thermal diffusivity provides a controlled, uniform heat release profile to the fixing belt. This local differentiation of thermal properties prevents hot spots and ensures uniform heat transmission, eliminating uneven glossiness while maintaining high fixing performance.
3Ease of manufacture
If the thermal diffusion member structure is simplified, then manufacturing cost is reduced, but heat transmission efficiency decreases
Solution Approach 1:
The invention extracts and separates the heat transmission function into two distinct layers with specialized roles. The base layer is optimized purely for heat absorption from the heater with high thermal diffusivity material, while the opposed layer is optimized for controlled heat release to the fixing belt with lower thermal diffusivity material. This functional extraction achieves high heat transmission efficiency using a relatively simple two-layer structure that can be manufactured cost-effectively compared to complex single-layer or multi-component systems.
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
The solution achieves improved fixing performance by uniformly transmitting heat to the fixing belt, reducing the likelihood of uneven glossiness and increasing the fixing limit temperature, while also reducing material costs and manufacturing complexity.
Implementation Method 1
The base layer and the opposed layer efficiently transmit heat generated by a heater to the belt member
Data Source
AI summary
A fixing device includes a belt member, a heater, a base layer, and an opposed layer. The heater is provided on an inner circumferential surface of the belt member. The base layer includes a first surface on a heater side and a second surface on an opposite side to the first surface. The opposed layer covers the second surface and is opposed to the inner circumferential surface of the belt member. The base layer and the opposed layer satisfy the following conditional expression (1),0<(Tb×Da)/(Ta×Db)≤1.17 (1)where Ta is a thickness of the base layer in millimeters, Tb is a thickness of the opposed layer in millimeters, Da is a thermal diffusivity of the base layer in square millimeters per second, and Db is a thermal diffusivity of the opposed layer in square millimeters per second.