Organic Photosensitive Layer Toughness and Surface Roughness Control
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Solution Overview
Problem
Electrophotographic photosensitive members face issues with cracking of the inorganic protective layer due to mechanical loads, and high surface roughness caused by silica particles, leading to image deletion, especially in high-temperature high-humidity environments.
Innovation Solution
Incorporating a binder resin with a viscosity-average molecular weight less than 50,000 and 40% by weight or more silica particles in the organic photosensitive layer to enhance the organic layer's toughness and reduce surface roughness, thereby minimizing cracking and improving cleaning properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silica particles are incorporated in the organic photosensitive layer to enhance toughness, then cracking of the inorganic protective layer is suppressed, but surface roughness increases leading to image deletion
Solution Approach 1:
The patent applies parameter changes by carefully controlling the viscosity-average molecular weight of the binder resin (setting it to less than 50,000) and optimizing the silica particle content (40% by weight or more). These parameter adjustments allow the organic photosensitive layer to achieve sufficient toughness to suppress cracking while maintaining surface smoothness to prevent image deletion, thus resolving the technical contradiction between strength and manufacturing precision.
2Manufacturing precision
If binder resin with low viscosity-average molecular weight is used to reduce surface roughness, then cleaning properties are improved, but toughness of the organic layer may be compromised
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the viscosity-average molecular weight parameter of the binder resin to be less than 50,000. This parameter optimization enables the resin to provide adequate toughness to the organic photosensitive layer while simultaneously maintaining low surface roughness, ensuring both mechanical strength and cleaning properties are satisfied.
3Strength
If high silica particle content (40% by weight or more) is used to suppress cracking, then mechanical strength is improved, but surface roughness increases causing image deletion
Solution Approach 1:
The patent applies parameter changes by optimizing the silica particle content to 40% by weight or more while simultaneously controlling the binder resin's viscosity-average molecular weight to less than 50,000. This combined parameter optimization allows the high silica content to provide crack resistance while the low molecular weight binder resin maintains surface smoothness, resolving the contradiction between strength and manufacturing precision.
Data Source
AI summary
An electrophotographic photosensitive member includes a conductive base; an organic photosensitive layer disposed on the conductive base, the organic photosensitive layer including a layer that constitutes a surface and contains a charge transport material, a binder resin having a viscosity-average molecular weight less than about 50,000, and silica particles in an amount of about 40% by weight or more; and an inorganic protective layer disposed on the organic photosensitive layer.