Modified Polysiloxane Charging Member Suppresses Compression Set
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Solution Overview
Problem
Electrophotographic charging members experience deformation known as compression set (C set) when in contact with electrophotographic photosensitive members for extended periods, leading to uneven electric resistance and charging performance, resulting in striped unevenness in images, especially under varying environmental conditions.
Innovation Solution
A modified polysiloxane surface layer with an ethylene oxide chain and a quaternary ammonium base or betaine structure is used, which improves ionic conductivity and suppresses molecular motion, maintaining uniform charging performance across different environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact charging method is used with a charging member in contact with the photosensitive member for extended periods, then charging function is achieved, but compression set (C set) occurs causing deformation and uneven electric resistance
Solution Approach 1:
The patent changes the material parameters of the charging member by incorporating a polymer with specific quaternary ammonium salt or quaternary ammonium base structures. This chemical composition modification alters the material's physical properties, specifically improving its resistance to compression set while maintaining ionic conductivity for charging function.
Solution Approach 2:
The charging member uses a composite material system combining polymer matrices with quaternary ammonium compounds. This composite structure integrates the charging functionality (through ion conductive agents) with enhanced mechanical stability (through the specific polymer structure), resolving the contradiction between maintaining charging function and preventing deformation.
2Reliability
If ion conductive agent is used to maintain conductivity, then charging performance is improved, but uneven distribution in C set portion causes electric resistance variation
Solution Approach 1:
The patent modifies the chemical structure of the conductive polymer itself, incorporating quaternary ammonium groups directly into the polymer chain. This structural change ensures that the ion conductive properties are inherent to the polymer matrix rather than dependent on separate conductive agents, preventing uneven distribution and maintaining uniform electric resistance even in compressed regions.
3Duration of action of stationary object
If charging member is left in high temperature and high humidity environment, then operational continuity is maintained, but degree of set becomes more serious
Solution Approach 1:
The patent changes the chemical composition of the charging member polymer to include structures with high thermal and humidity resistance. The quaternary ammonium-containing polymer structure maintains its mechanical properties and resistance to compression set under elevated temperature and humidity conditions, enabling continuous operation without accelerated degradation.
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 modified polysiloxane surface layer effectively reduces the occurrence of C set and electric resistance variations, preventing C set images and ensuring stable, high-quality electrophotographic image formation across a wide range of conditions.
Implementation Method 1
the surface layer comprises a modified polysiloxane having a structure represented by the following formula (1)... improves ionic conductivity
Implementation Method 2
suppresses molecular motion, maintaining uniform charging performance across different environments
Data Source
AI summary
The present invention provides an electrophotographic member capable of more definitely suppressing occurrence of a C set image. The electrophotographic member has a surface layer including a modified polysiloxane having a structure represented by the following formula (1). In the formula (1), G represents a bivalent group having an ethylene oxide chain represented by (—O—C2H4—) and L represents polysiloxane having at least a SiO4/2(Q) unit or a SiO3/2(T) unit.