Porous Elastic Layer Pressing Member for Fixing Film Eccentricity
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Solution Overview
Problem
The existing fixing apparatuses in image forming systems face issues with film eccentricity, leading to biasing forces that can damage the film due to misalignment between the film and pressing roller, which is difficult to eliminate and results in edge wear or breakage.
Innovation Solution
A fixing apparatus with a pressing member featuring a porous elastic layer formed from a sponge-forming liquid silicone rubber composition, where the orientation of pore portions is controlled to reduce biasing forces by anisotropic deformation, and the angles of major axis direction vectors of pores are optimized to counteract the eccentricity-induced forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a film heating system with an endless fixing film is used, then the heat capacity and size of the film are reduced and energy consumption is decreased, but film eccentricity occurs causing the film to abut the flange and potentially damage the edge portion
Solution Approach 1:
The pressing roller incorporates a porous elastic layer with controlled pore structure. The porosity reduces the thermal conductivity of the elastic layer, preventing excessive heat transfer to the film and reducing thermal expansion differences that cause eccentricity. This maintains film positioning accuracy while preserving the energy efficiency of the film heating system.
Solution Approach 2:
The invention changes the thermal and mechanical parameters of the pressing roller by controlling the pore radius (5-50 μm), porosity (30-70%), and pore distribution in the elastic layer. These parameter adjustments optimize the balance between heat insulation (to maintain film positioning) and heat transfer (for efficient warming up), resolving the contradiction between energy consumption and film durability.
2Loss of time
If the elastic layer of the pressing roller is made porous to reduce heat capacity and thermal conductivity, then the warm-up time is shortened, but the pressing force distribution becomes uneven causing anisotropic deformation
Solution Approach 1:
The invention applies local quality by creating non-uniform pore distribution within the elastic layer. The pore density and size vary at different locations and depths of the elastic layer, allowing different regions to have optimized thermal and mechanical properties. This local variation enables shortened warm-up time in heat-contact regions while maintaining pressing force uniformity in load-bearing regions.
Solution Approach 2:
The porous structure exhibits asymmetric characteristics with pores having specific orientation angles (30°-60° or 120°-150° relative to the rotation axis). This asymmetric pore arrangement creates controlled anisotropic deformation that compensates for eccentricity-induced uneven pressing forces, maintaining overall pressing force uniformity while enabling rapid heat transfer.
3Ease of manufacture
If the degree of parallel and alignment between the film and pressing roller deviates, then assembly is simplified, but the biasing force increases causing the film to abut the flange and potentially break
Solution Approach 1:
The porous elastic layer acts as a cushioning element that compensates for misalignment before it causes damage. The compressible porous structure absorbs positional deviations and eccentricity-induced forces, preventing the film from abutting the flange. This cushioning effect allows simpler assembly with relaxed alignment tolerances while maintaining proper film positioning during operation.
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 reduces film biasing forces, enhancing the durability of the fixing apparatus by minimizing edge damage and ensuring prolonged film lifespan.
Implementation Method 1
forming the rubber elastic layer of the pressing roller as a porous elastic layer having a plurality of pore portions and thus reducing heat transmitted to the pressing roller from the film heated by the operation of the fixing apparatus
Implementation Method 2
A plurality of pore portions connected to each other are provided in the elastic layer... the orientation of pore portions is controlled to reduce biasing forces by anisotropic deformation
Data Source
AI summary
A fixing apparatus includes an endless belt, and a pressing member including a base body and an elastic layer formed on the base body. A plurality of pore portions connected to each other are provided in the elastic layer. In a case where a binary image is generated from a three-dimensional image of the elastic layer, a threshold value X μm corresponding to opening processing with which a number of pores derived from the pore portions takes a maximum value is obtained, and then pores derived from the pore portions in the elastic layer are extracted by performing opening processing with a threshold value of 2X μm, an average value of angles θ is 120° or larger and smaller than 150°.