Developing Roller Surface Layer Adhesion High Humidity
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Solution Overview
Problem
Developing rollers used in electrophotographic apparatuses face issues with surface layer peeling off under high temperature and humid environments, and toner adhesion leading to image unevenness, as silicone rubber materials have low polarity and high water absorption rates.
Innovation Solution
A developing roller with a surface layer containing a specific polyurethane resin structure, including addition curable-type dimethyl silicone rubber and urethane resin, which provides high adhesiveness to the elastic layer and reduces toner adhesion, maintaining image quality and durability even in severe conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyurethane surface layer is provided on a silicone rubber elastic layer to suppress problems under various environments, then the surface layer peels off under high temperature and high humidity conditions
Solution Approach 1:
The invention changes the chemical composition parameters of the polyurethane surface layer by incorporating specific structural units (formulae 1-4) that enhance adhesion to silicone rubber. This parameter change in the polymer structure resolves the contradiction by maintaining both environmental stability and strong bonding between layers.
Solution Approach 2:
The invention creates a composite material system where a specifically structured polyurethane surface layer is combined with silicone rubber elastic layer. The composite structure with tailored molecular architecture provides both the required environmental resistance and interlayer adhesion strength simultaneously.
2Ease of operation
If silicone rubber is used as the elastic layer material, then flexibility and deformation recoverability are improved, but toner strongly adheres to the surface causing image unevenness
Solution Approach 1:
The invention applies local quality by providing a specifically structured polyurethane surface layer on the silicone rubber elastic layer. The surface layer has different chemical properties from the bulk elastic layer, creating a localized modification that reduces toner adhesion while preserving the underlying silicone rubber's flexibility and elastic properties.
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 surface layer peeling and toner adhesion, ensuring high-quality electrophotographic images and stable output under high temperature and humidity, enhancing the durability and flexibility of the developing roller.
Implementation Method 1
a surface layer including a polyurethane resin having a specific structure is provided on an elastic layer containing a cured material of an addition curable-type dimethyl silicone rubber
Implementation Method 2
the urethane resin has, between two adjacent urethane, a structure represented by the following formula (1), and at least one structure selected from the group consisting of a structure represented by the following formula (2) and a structure represented by the following formula (3)
Data Source
AI summary
A developing roller used for formation of an electrophotographic image with high quality is provided in which even in storage and use under a high temperature and high humidity environment, peel-off of a surface layer from an elastic layer is suppressed, and a toner hardly adheres to the surface of the developing roller. The developing roller is a developing roller including a mandrel, an elastic layer provided on the mandrel and containing a cured material of an addition curable-type dimethyl silicone rubber, and a surface layer containing a urethane resin that covers the circumferential surface of the elastic layer, wherein the urethane resin has a structure represented by the following formula (1), and one or both structures selected from a structure represented by the following formula (2) and a structure represented by the following formula (3) between two adjacent urethane linkages. ―CH2-CH2-CH2-CH2-O― formula (1)