Charging Member Surface Layer with Si-O-Ti Bonds
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Solution Overview
Problem
The challenge is to achieve a balance between suppressing the bleeding of low-molecular weight components from the elastic layer of a charging member in electrophotographic apparatuses while maintaining stable and effective charging performance, especially with the increased speed of the electrophotographic process.
Innovation Solution
A charging member is designed with a conductive substrate, a conductive elastic layer, and a surface layer containing a polymer with Si—O—Ti bonds, which has a specific constitutional unit structure to prevent bleeding and enhance charging performance. The surface layer is formed through a crosslinking process using hydrolyzable silane and titanium compounds, allowing for improved adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a thick inorganic oxide coating or inorganic-organic hybrid coating is formed on the peripheral surface of the elastic layer to suppress bleeding of low-molecular weight component, then the bleeding suppression is improved, but the charging performance deteriorates due to increased film thickness
Solution Approach 1:
The patent changes the chemical composition parameters of the surface layer by incorporating specific inorganic compounds (silane-modified polymers, titanium oxide, zirconium oxide, hafnium oxide) and controlling their ratios. This allows achieving effective bleeding suppression with a thinner film (1-10 μm) compared to conventional coatings, thereby maintaining charging performance while suppressing low-molecular weight component bleeding.
Solution Approach 2:
The patent creates a composite surface layer combining organic polymers (silane-modified acrylic, polyurethane, or polyester) with inorganic oxide particles (titanium oxide, zirconium oxide, hafnium oxide). This composite structure provides both bleeding suppression functionality and maintains appropriate surface properties for charging, resolving the contradiction between thick coating for bleeding suppression and thin coating for charging performance.
2Productivity
If the electrophotographic process speed is increased to improve productivity, then the productivity is improved, but the charging stability deteriorates due to reduced contact time between photosensitive member and charging member
Solution Approach 1:
The patent modifies the surface electrical properties by incorporating inorganic oxide particles with high dielectric constants (titanium oxide, zirconium oxide, hafnium oxide) into the surface layer. This enhances the charging efficiency and stability, allowing the system to maintain reliable charging even when contact time is reduced due to increased process speeds.
3Object-generated harmful factors
If a conventional inorganic oxide coating is applied to suppress bleeding, then the bleeding suppression is improved, but the adhesion and durability of the coating deteriorate
Solution Approach 1:
The patent creates a composite structure where inorganic oxide particles are embedded within a polymer matrix containing silane-modified polymers. The silane groups form chemical bonds with the inorganic oxide particles, creating strong adhesion between the coating layers and preventing peeling or flaking, thereby improving durability while maintaining bleeding suppression.
Solution Approach 2:
The silane-modified polymer acts as an intermediary between the elastic layer and the inorganic oxide coating. The silane groups in the polymer form chemical bonds with the inorganic oxide particles, creating a strong bonding interface that improves adhesion and prevents coating failure, resolving the contradiction between bleeding suppression and coating durability.
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
This configuration effectively suppresses the bleeding of low-molecular weight components and ensures excellent charging performance, enabling the stable formation of high-quality electrophotographic images even at increased process speeds.
Implementation Method 1
the surface layer contains a polymer having a Si—O—Ti bond, and the polymer has a constitutional unit represented by the following general formula (1) and a constitutional unit represented by the following general formula (2)
Implementation Method 2
The surface layer is formed through a crosslinking process using hydrolyzable silane and titanium compounds
Implementation Method 3
The surface layer is formed through a crosslinking process using hydrolyzable silane and titanium compounds
Data Source
AI summary
A charging member that achieves a high level of compatibility between the suppression of the bleeding of a low-molecular weight component from its elastic layer to its surface and charging performance for an electrophotographic photosensitive member. The charging member has a substrate, an elastic layer, and a surface layer. The surface layer contains a polymer having a Si-O-Ti bond, and the polymer has a constitutional unit represented by the following general formula (1) and a constitutional unit represented by the following general formula (2).