Electrophotographic Photosensitive Member With Soluble Polyarylate Coating
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Solution Overview
Problem
Existing electrophotographic photosensitive members face challenges in achieving optimal abrasion resistance and scratch resistance while maintaining solubility in solvents, particularly in the context of polyarylate resins used in their photosensitive layers.
Innovation Solution
The use of a polyarylate resin comprising specific repeating units, with a controlled ratio of these units, enhances the solubility, abrasion resistance, and scratch resistance of the photosensitive layer by incorporating a charge generating material, a hole transport material, and an electron transport material within a single-layer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyarylate resin is used in the photosensitive layer to improve abrasion resistance and scratch resistance, then the durability is enhanced, but the solubility in solvents deteriorates
Solution Approach 1:
The patent modifies the chemical structure parameters of the polyarylate resin by incorporating specific repeating units with controlled ratios. The resin contains repeating units where R1 and R2 are hydrogen atoms or methyl groups, with specific constraints on the divalent groups X and W. By adjusting the molecular structure parameters (substituent types, positions, and ratios of different repeating units), the patent achieves both high abrasion resistance and maintained solubility in conventional solvents used in photosensitive layer fabrication.
Solution Approach 2:
The patent creates a composite polyarylate resin system by combining multiple types of repeating units (with different R1, R2, X, and W group configurations) in specific ratios. This composite structure integrates the hard, abrasion-resistant characteristics of certain polyarylate configurations with the solubility-enhancing properties of other configurations, achieving a balanced material that satisfies both durability and manufacturability requirements.
2Reliability
If the polyarylate resin structure is modified to enhance scratch resistance, then the reliability is improved, but the solubility in solvents deteriorates
Solution Approach 1:
The patent achieves improved scratch resistance while maintaining solubility by precisely controlling the molecular parameters of the polyarylate resin. The repeating units are designed with specific divalent groups (X and W) and substituent patterns (R1 and R2), where the combination and ratio of these parameters create a molecular structure that provides scratch resistance through enhanced chain rigidity and intermolecular interactions, while the presence of appropriate aromatic rings and substituent types maintains compatibility with organic solvents used in coating processes.
Data Source
AI summary
A single-layer photosensitive layer included in an electrophotographic photosensitive member contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4).The percentage of the number of repeats of the repeating unit represented by formula (3) relative to a total of the number of repeats of the repeating unit represented by formula (1) and the number of repeats of the repeating unit represented by formula (3) is greater than 0% and less than 20%.