Electrophotographic Photoreceptor Surface Layer Cross-Linking
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Solution Overview
Problem
Existing electrophotographic photoreceptors face issues with abrasion resistance, crack resistance, and durability due to the permeation of low molecular weight polymerizable compounds into the photosensitive layer, leading to mechanical and electric stress, which causes cracking and deteriorates charging performance.
Innovation Solution
A surface layer formed by polymerizing a polymerizable compound with seven to ten functional groups and a reactive group equivalent of 100 to 140, containing acryloyloxy or methacryloyloxy groups, and incorporating metal oxide particles like alumina or tin oxide, which are surface-treated with reactive organic groups, to enhance cross-linking density and prevent permeation into the photosensitive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low molecular weight polymerizable compound is used to form a surface layer, then the surface layer can be formed easily, but the compound permeates into the photosensitive layer causing mechanical stress and cracking
Solution Approach 1:
The patent changes the molecular weight parameter of the polymerizable compound from low (conventional) to high (10,000-100,000), which fundamentally alters the compound's penetration behavior while maintaining surface layer formation capability. This parameter change prevents permeation into the photosensitive layer, eliminating the source of mechanical stress and cracking.
Solution Approach 2:
The patent creates a composite surface layer by combining a high molecular weight polymerizable compound with a polymerization initiator. This composite material system achieves both ease of manufacture (through simple coating and photopolymerization) and high reliability (through the non-permeating nature of the high molecular weight compound that prevents cracking).
2Productivity
If the contact pressure of the cleaning blade is increased to overcome toner slippage, then toner removal efficiency is improved, but the photoreceptor surface is abraded resulting in deteriorated charging performance
Solution Approach 1:
The patent applies preliminary action by forming a protective surface layer on the photoreceptor before the cleaning process. This surface layer acts as a sacrificial protective barrier that absorbs the mechanical stress from high-pressure blade cleaning, preventing direct contact between the blade and the underlying photosensitive layer. The surface layer can be replenished through continuous supply from the bulk material, maintaining long-term protection without deteriorating charging performance.
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 provides a photoreceptor with improved flaw resistance, abrasion resistance, and crack resistance, maintaining high durability and image quality over a long period by preventing cracking of the photosensitive layer and enhancing the mechanical strength of the surface layer.
Implementation Method 1
a surface layer formed by polymerizing a polymerizable compound with seven to ten functional groups
Data Source
AI summary
An electrophotographic photoreceptor is disclosed, comprising, on an electrically conductive substrate, a photosensitive layer and a surface layer provided sequentially in that order, in which the surface layer is a layer formed by polymerizing a polymerizable compound (I) containing seven to ten functional groups and exhibiting a reactive group equivalent of not more than 140 and not less than 100.