Electrophotographic Photosensitive Member Surface Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrophotographic photosensitive members face issues with image deterioration due to scratches caused by external forces, leading to poor image quality over time, despite efforts to improve mechanical strength and surface roughening techniques.
Innovation Solution
The introduction of a surface structure with independent depressed portions on the electrophotographic photosensitive member, where the surface is divided into specific regions and zones, with depressed portions having defined diameters and distances, effectively preventing scratches from growing and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mechanical strength of surface layers is improved by using high-strength binder resins or cured layers, then the durability against scratches and wear is improved, but the surface becomes more susceptible to scratches from external forces
Solution Approach 1:
The invention applies local quality by creating depressed portions at specific locations on the surface layer. These depressed portions are positioned to intercept scratches before they can propagate through the surface, providing localized protection without compromising the overall mechanical strength of the surface layer. The depressed portions act as sacrificial elements that absorb the impact of external forces.
Solution Approach 2:
The depressed portions are pre-formed on the surface layer before the electrophotographic photosensitive member is put into service. This preliminary action creates a protective structure in advance that prevents scratches from forming in the first place, rather than attempting to repair or protect after scratches occur.
2Ease of operation
If the surface is roughened to improve cleaning performance, then the cleaning ability is enhanced, but the surface becomes more prone to scratches and image deterioration
Solution Approach 1:
The invention segments the surface into multiple depressed portions distributed across the surface layer. This segmentation creates a pattern that maintains cleaning effectiveness while providing multiple localized protection points against scratches. The depressed portions are distributed in a way that balances cleaning performance with scratch resistance.
Solution Approach 2:
The depressed portions create local variations in surface quality that enhance cleaning performance in certain areas while providing protective functions in others. The local depression structures allow for effective cleaning without creating a uniformly rough surface that would be susceptible to scratches.
3Adaptability or versatility
If a multi-layer type photosensitive layer is used to achieve high sensitivity and material designing flexibility, then the functional performance is improved, but the complexity of the structure increases
Solution Approach 1:
The invention uses composite materials by combining the multi-layer photosensitive layer structure with the depressed portion surface modification. The photosensitive layer maintains its multi-layer composite structure for functional performance, while the depressed portions add a structural element for mechanical protection. This composite approach integrates multiple functions without excessive complexity.
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 1G~1H
AI summary
To provide an electrophotographic photosensitive member which keeps the member surface from being scratched in a size causative of faulty images, without relying on improving mechanical strength and can form good images over a long period of time, and a process cartridge and an electrophotographic apparatus, having the photosensitive member. In an electrophotographic photosensitive member having a support and a photosensitive layer, the photosensitive member has a surface having a plurality of independent, depressed portions each having a major-axis diameter of 0.1 µm to 10 µm, a minor-axis diameter of 0.1 µm to 10 µm and a deepest-part to opening distance of 0.1 µm to 10 µm; and, where the surface is equally divided into 4 regions in the rotational direction, which are then equally divided into 25 regions in the direction falling at right angles with the rotational direction, to obtain 100-spot regions A in total, and, in each thereof, square regions B of 50 µm each per side one side of which is parallel to the rotational direction are provided and the regions B are each equally divided into 500 zones by straight lines parallel to the rotational direction, 400 to 499 lines among the straight lines pass through the depressed portions in each of the regions B.