Fixing Rotating Member Structure to Prevent Heating Layer Cracks
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Solution Overview
Problem
Existing fixing rotating members in electrophotographic image forming apparatuses experience durability issues due to cracks and rupture in the heating layer, particularly at the ends, caused by differences in material properties and temperature-dependent elastic moduli of the base and protective layers, leading to reduced conductivity and uneven heating.
Innovation Solution
A fixing rotating member design with a first resin layer, a heating layer, a second resin layer, an elastic layer, and a surface layer, where the first and second resin layers have a temperature-dependent elastic modulus difference of at least 10%, and the neutral axis is positioned in the heating layer or second resin layer in both central and end regions, ensuring balanced tensile and compression stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heating layer is made of metal material for electromagnetic induction heating, then heating efficiency is improved, but cracks and rupture occur in the heating layer due to strain during bending deformation
Solution Approach 1:
The patent positions the heating layer at the neutral axis where bending strain is minimized, converting the potential harm of metal layer cracking during bending into a benefit by ensuring the heating layer remains intact and functional throughout repeated bending cycles while maintaining electromagnetic induction heating efficiency
Solution Approach 2:
The patent changes the positional parameter of the heating layer from the outer surface to the neutral axis in the thickness direction, and adjusts the thickness parameters of the base layer and protective layer to achieve optimal stress distribution that prevents heating layer rupture while maintaining heating performance
2Stress or pressure
If the neutral axis is positioned in the base layer or protective layer, then bending stress is reduced, but the heating layer becomes vulnerable to cracks and rupture
Solution Approach 1:
The patent uses the neutral axis as an intermediary position for the heating layer, located between the tensile and compressive stress zones in the bending direction, allowing the heating layer to be protected from extreme stress while maintaining its heating function
Solution Approach 2:
The patent creates a composite structure with the base layer, heating layer, and protective layer where each layer has specific thickness and material properties that work together to position the neutral axis appropriately and protect the heating layer from damage
3Productivity
If the fixing rotating member is heated to high temperature for efficient toner fixing, then fixing performance is improved, but temperature difference between central and end regions causes uneven stress distribution
Solution Approach 1:
The patent applies different thickness specifications for the base layer and protective layer at different regions (central region vs. end region) of the fixing rotating member, creating local variations in layer thickness that compensate for temperature-induced stress differences and ensure uniform stress distribution across the entire member
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 design enhances durability by minimizing stress-induced cracks and maintaining stable heating performance across the rotating member, improving the quality and stability of electrophotographic image formation.
Implementation Method 1
A fixing apparatus having a fixing rotating member equipped with a conductive layer, and a method of heating the conductive layer by electromagnetic induction heating has been put into actual use. A fixing apparatus having an electromagnetic induction heating system can heat a fixing rotating member in a short time.
Implementation Method 2
the metal layer is formed in the vicinity of the neutral axis where no strain is caused when bending deformation is caused at the belt. Herein, it is described that the neutral axis is the line of intersection between the surface that does not undergo strain when bending deformation is caused at the fixing belt, and the cross section of the fixing belt
Data Source
AI summary
A fixing rotating member comprising: a first resin layer having an endless shape; at least one heating layer on the first resin layer; a second resin layer on the heating layer; an elastic layer on the second resin layer; and, a surface layer on the elastic layer, wherein the first resin layer and the second resin layer are different from in elastic modulus at a specific temperature by at least 10%, and a neutral axis in a thickness direction of the fixing rotating member is located in the heating layer or in the second resin layer in the central region and the end region, the end region is a region from both ends of the heating layer in the width direction to a specific length toward a center, and the central region is a region of a specific length from the center to both ends.