Electrophotographic Photoreceptor With Surface Particle Gradient
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Solution Overview
Problem
Existing electrophotographic photoreceptors face a trade-off between improving the break resistance of the inorganic protective layer and maintaining sufficient optical transmittance of the charge transport layer, as high loading of inorganic oxide particles enhances hardness but reduces light transmission.
Innovation Solution
The photoreceptor is designed with a specific distribution of inorganic oxide particles in the charge transport layer, where the percentage area of particles at the surface level exceeds that of the inner level, ensuring a boundary at half the layer's thickness, allowing for enhanced break resistance while maintaining optical transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic oxide particles are highly loaded in the charge transport layer, then break resistance of the inorganic protective layer is improved, but optical transmittance of the charge transport layer deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of inorganic oxide particles within the charge transport layer. Specifically, the surface level (within 50 nm from the surface) contains a higher concentration of inorganic oxide particles compared to the inner level, achieving a gradient structure. This localized concentration strategy enhances break resistance at the critical surface region where the inorganic protective layer forms, while maintaining adequate optical transmittance in the bulk material that light must traverse.
2Ease of manufacture
If inorganic oxide particles are distributed uniformly throughout the charge transport layer, then manufacturing simplicity is maintained, but break resistance of the inorganic protective layer is insufficient
Solution Approach 1:
The patent implements local quality by specifying that the inorganic oxide particles should be concentrated in the surface level of the charge transport layer, with the percentage area of particles in the surface level being greater than in the inner level. This creates a functionally optimized structure where the surface region has enhanced mechanical properties to support the inorganic protective layer, while the bulk maintains sufficient optical properties.
3Strength
If inorganic oxide particles are concentrated at the surface level of the charge transport layer, then break resistance of the inorganic protective layer is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating a gradient distribution of inorganic oxide particles where the surface level (within 50 nm from the surface) contains a higher concentration compared to the inner level. This approach optimizes break resistance at the critical surface interface while managing manufacturing precision through defined spatial zones.
Solution Approach 2:
The patent employs parameter changes by controlling the concentration and spatial distribution of inorganic oxide particles through specific parameters: particle size (5-200 nm), concentration gradient (percentage area A > percentage area B), and depth distribution (surface level within 50 nm vs. inner level). These parameter optimizations enable the gradient structure to form with controlled precision during the coating process.
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate, a charge-generating layer provided on or above the conductive substrate, a charge transport layer provided on the charge-generating layer and containing inorganic oxide particles, the charge-generating layer and the charge transport layer forming a photosensitive layer, and an inorganic protective layer provided on the photosensitive layer, in which in a cross-sectional observation of the charge transport layer, the relationship between the percentage area A of inorganic oxide particles contained in a surface level and the percentage area B of inorganic oxide particles contained in an inner level satisfies the percentage area A>the percentage area B of the charge transport layer, with the boundary therebetween at ½ the thickness of the charge transport layer.