Fixing Belt Polyimide Imidization Gradient Peeling
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Solution Overview
Problem
Existing fixing belts in image forming apparatuses face peeling issues between the polyimide resin base layer and the metal layer, especially in high-temperature high-humidity environments, leading to reduced adhesive strength and potential cracking of the metal layer.
Innovation Solution
A fixing belt with an annular polyimide resin base layer having a lower imidization ratio on the outer peripheral surface than in the central portion, combined with a metal layer on the outer peripheral surface and an elastic layer, which enhances adhesion through increased wettability and interaction between the polar groups and the metal layer, thereby suppressing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the polyimide resin base layer has a high imidization ratio throughout the thickness direction, then the adhesive strength between the polyimide resin base layer and the metal layer is improved, but peeling occurs between the polyimide resin base layer and the metal layer when stored in a high-temperature high-humidity environment
Solution Approach 1:
The patent applies local quality by creating a gradient imidization ratio distribution within the polyimide resin base layer. The outer peripheral surface region (within 100 μm from the surface) has a lower imidization ratio (50-90%) compared to the central portion (90-100%). This local variation in chemical composition allows the outer surface to maintain better adhesion to the metal layer in high-humidity environments while the inner portion provides structural stability, thereby resolving the contradiction between adhesive strength and peeling resistance.
2Temperature
If the imidization ratio is uniformly high throughout the polyimide resin base layer, then thermal stability is improved, but wettability with the metal layer decreases leading to poor adhesion
Solution Approach 1:
The patent implements local quality by establishing a spatial gradient in imidization ratio within the polyimide resin base layer. The outer peripheral surface region (within 100 μm from the surface) maintains a lower imidization ratio (50-90%) to enhance wettability and adhesion to the metal layer, while the central portion maintains a high imidization ratio (90-100%) to provide thermal stability. This local differentiation resolves the contradiction between thermal stability and adhesive strength.
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 effectively suppresses peeling between the polyimide resin base layer and the metal layer in high-temperature high-humidity conditions, improving the durability and reducing the likelihood of cracking in the metal layer, thus enhancing the belt's performance and longevity.
Implementation Method 1
enhances adhesion through increased wettability and interaction between the polar groups and the metal layer
Implementation Method 2
interaction between the polar groups and the metal layer
Implementation Method 3
fixing belt for electromagnetic induction heating, including a polyimide resin layer, a metal layer formed on the surface of the resin layer to generate heat by electromagnetic induction
Data Source
AI summary
A fixing belt includes an annular polyimide resin base layer having a lower imidization ratio in the outer peripheral surface than in a central portion in the thickness direction, a metal layer provided on the outer peripheral surface of the polyimide resin base layer, and an elastic layer provided on the outer peripheral surface of the metal layer.