Gradient Crosslinked Developing Member Surface
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Solution Overview
Problem
Electrophotographic developing members with high surface hardness prevent deformation but tend to stick to developers, leading to image quality issues over time.
Innovation Solution
An electrophotographic developing member with a surface layer containing a urethane resin, where the crosslinking density varies from the surface to deeper regions to balance stickiness and deformation resistance, achieved through specific plasma processing under atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface hardness of the developing member is increased to prevent deformation, then the developing member can maintain its shape when contacted by developing blades, but the developer tends to stick to the surface causing image quality degradation
Solution Approach 1:
The patent applies local quality by creating a surface layer with non-uniform crosslinking density distribution. The crosslinking density is higher near the surface (within 100nm depth) and gradually decreases toward the bulk material, resulting in a surface region with different properties (lower developer sticking) from the interior (higher structural strength). This gradient structure allows the surface to resist developer adhesion while the bulk maintains mechanical integrity and resistance to deformation.
Solution Approach 2:
The patent utilizes parameter changes by controlling the crosslinking density parameter within specific ranges (C1: 3.0×10^-4 to 8.0×10^-4 mol/cm³, C2: 2.0×10^-4 to 7.0×10^-4 mol/cm³, C3: 1.5×10^-4 to 6.0×10^-4 mol/cm³) to achieve optimal balance between developer sticking prevention and deformation resistance. The crosslinking density is adjusted through plasma treatment conditions (power, time, gas composition) to create the desired gradient profile.
2Stability of the object's composition
If the surface layer crosslinking density is increased to prevent deformation, then the surface becomes more resistant to contacting members, but the developer sticking problem worsens
Solution Approach 1:
The patent implements local quality through spatial variation of crosslinking density within the surface layer. By creating regions with different crosslinking densities at different depths (higher C1 near surface, lower C3 deeper), the surface exhibits locally optimized properties for preventing developer sticking, while the underlying layers provide structural stability and resistance to deformation from contacting members.
Solution Approach 2:
The surface layer functions as a composite structure with varying crosslinking density zones, effectively creating a multi-phase material system. The gradient crosslinked urethane resin structure combines regions of different molecular network densities, allowing the material to simultaneously exhibit low surface energy characteristics (reducing developer sticking) and high mechanical stability (resisting deformation).
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 developing member effectively prevents developer sticking and deformation, ensuring stable image formation over a long period by controlling crosslinking density and oxygen content in the surface layer.
Implementation Method 1
the step of subjecting a coating film of a raw-material solution for the surface layer to plasma processing under atmospheric pressure
Data Source
AI summary
To provide an electrophotographic developing member which can both be kept from the sticking of a developer and be kept from being deformed by its contacting members, and can form stable images over a long period of time. An electrophotographic developing member characterized in that its surface layer satisfies the following expressions (1) to (3) where the average crosslinking density in each region of up to 100 nm in depth, from 100 nm to 200 nm in depth and from 200 nm to 300 nm in depth from the surface of the surface layer is represented by C1, C2 and C3 (mol/cm3), respectively:C3<C2<C1; (1)C3×1.3≦C1≦C3×5.0; and (2)2.0×10−4≦C3≦7.0×10−4. (3)