Polyarylate Polycarbonate Surface Layer Scratch Resistance
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Solution Overview
Problem
Electrophotographic photosensitive members experience streaky image damage due to scratches in low-temperature and low-humidity environments, primarily caused by external additives and hard foreign matter, which existing polyarylate and polycarbonate compositions fail to adequately resist.
Innovation Solution
A surface layer comprising a polyarylate with specific structural units and a polycarbonate, where the polyarylate has structural units represented by formulas (1-1), (1-2), and (1-3), and the polycarbonate has structural units represented by formula (2-1), enhancing scratch resistance through improved entanglement and absorption of external impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyarylate and polycarbonate are mixed in the photosensitive layer to improve wear resistance and scratch resistance, then the contact surface with external substances decreases, but fine projections and recesses are formed on the surface due to poor uniform dispersion
Solution Approach 1:
The patent uses a composite material system consisting of polyarylate and polycarbonate resins in the surface layer to achieve both wear resistance and scratch resistance. The specific combination of these two polymer materials creates a composite structure that leverages the complementary properties of each component to resolve the contradiction between improved strength and surface uniformity.
2Reliability
If the photosensitive member is used in a low-temperature and low-humidity environment, then the contact member becomes hard due to low temperature influence, but this causes external additives and hard foreign matter to be caught and generates scratches
Solution Approach 1:
The patent changes the physical and chemical parameters of the surface layer by selecting specific polyarylate and polycarbonate materials with appropriate glass transition temperatures and molecular structures. This parameter optimization ensures the surface layer maintains adequate flexibility and impact absorption capability even when the contact member hardens in low-temperature environments, preventing scratch generation from foreign matter.
Solution Approach 2:
The patent applies local quality by creating a surface layer with specifically engineered properties that differ from the bulk photosensitive layer. The surface layer is composed of a tailored mixture of polyarylate and polycarbonate to provide localized shock absorption and flexibility at the interface with contact members, while the underlying layers maintain their electrophotographic functionality.
3Ease of manufacture
If existing polyarylate and polycarbonate compositions are used, then the photosensitive layer provides basic functionality, but it fails to adequately resist scratches caused by external additives and hard foreign matter in low-temperature environments
Solution Approach 1:
The patent optimizes the molecular structure parameters of the polyarylate and polycarbonate, including glass transition temperature, molecular weight, and compositional ratios. These parameter changes enhance the material's ability to absorb external impacts and resist scratches from foreign matter, while maintaining compatibility with existing manufacturing processes for photosensitive layers.
Data Source
AI summary
Provided is an electrophotographic photosensitive member in which streaky image damage can be suppressed throughout long-term use in a low-temperature and low-humidity environment. An electrophotographic photosensitive member having a surface layer comprising a polyarylate and a polycarbonate, wherein the polyarylate has at least one structural unit selected from the group consisting of a structural unit represented by the following formula (1-1), a structural unit represented by the following formula (1-2) and a structural unit represented by the following formula (1-3), and the polycarbonate has a structural unit represented by the following formula (2-1).