Urethane Resin Developing Member for Toner Charge Leakage
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Solution Overview
Problem
Existing electrophotographic developing members face challenges in maintaining high-quality image formation over time due to toner charge leakage and surface layer hardness, leading to image degradation and 'fogging' issues.
Innovation Solution
A developing member with a substrate, elastic layer, and surface layer containing a urethane resin with specific structural formulas, which increases electric resistance and softness, reducing toner charge leakage and surface layer separation, while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional urethane resin is used in the surface layer, then the surface layer has sufficient mechanical strength, but the electric resistance is low causing toner charge leakage and image degradation
Solution Approach 1:
The patent changes the chemical structure parameters of the urethane resin by introducing specific side chain configurations (formulae 2-5) between urethane linkages. This structural modification increases the electric resistance of the surface layer while maintaining its mechanical properties, thereby preventing toner charge leakage and ensuring stable image quality over time.
Solution Approach 2:
The surface layer is designed as a composite material containing both the modified urethane resin and conductive particles (such as carbon black). This composite structure achieves optimal balance between electric resistance and conductivity, preventing charge leakage while maintaining necessary electrical properties for toner transport.
2Strength
If the surface layer is made harder to improve durability, then mechanical strength increases, but toner charge leakage worsens and image quality degrades
Solution Approach 1:
The patent modifies the urethane resin structure to achieve the right balance between hardness and electric resistance. The specific side chain structures (formulae 2-5) provide adequate mechanical strength for durability while simultaneously increasing electric resistance to prevent charge leakage, thus resolving the contradiction between strength and image quality.
3Productivity
If the developing member is used over a long period, then productivity is maintained, but surface layer separation occurs and image quality degrades
Solution Approach 1:
The modified urethane resin structure with specific side chains (formulae 2-5) provides enhanced stability that prevents surface layer separation during prolonged operation. The structural modifications improve the resin's resistance to degradation while maintaining adhesion to the substrate, ensuring both long-term productivity and composition stability.
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 enables stable, high-quality electrophotographic image formation over a long period by preventing toner charge leakage and surface layer separation, thus reducing 'fogging' and ensuring durability.
Implementation Method 1
the urethane resin has: the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3) between two adjacent urethane linkages; and the structure represented by structural formula (4) and the structure represented by structural formula (5) between two adjacent urethane linkages
Data Source
AI summary
A developing member includes a substrate, an elastic layer, and a surface layer in that order. The surface layer contains a urethane resin and a filler. The urethane resin has: the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3), between two adjacent urethane linkages; and the structure represented by structural formula (4) and the structure represented by structural formula (5), between two adjacent urethane linkages. The structural formulas (1) to (5) are as follows: