Electrophotographic Photosensitive Member Recessed Surface Structure
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Solution Overview
Problem
Conventional electrophotographic photosensitive members face issues with image deletion due to the deterioration of surface materials caused by oxidized gases and moisture, leading to reduced durability and image quality, particularly when recessed portions are designed without considering their arrangement.
Innovation Solution
The electrophotographic photosensitive member is designed with recessed portions of specific dimensions and arrangements on its surface, optimized to minimize image deletion by maintaining a high area ratio of flat portions and controlling the image quality lowering index through precise arrangement and depth, ensuring effective cleaning and image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a resin material having a high anti-wearing property is used in the surface layer, then the durability against external forces is improved, but image deletion occurs due to material deterioration by oxidized gas and moisture
Solution Approach 1:
The invention applies a porous coating layer on the surface of the electrophotographic photosensitive member. This porous structure provides hydrophobicity to repel moisture and oxidized gas, preventing material deterioration while maintaining high anti-wearing properties. The porous structure allows the surface to be both durable and resistant to environmental degradation that causes image deletion.
Solution Approach 2:
The invention uses a composite structure combining a resin material with high anti-wearing property and a porous coating layer. This composite approach allows the base resin to provide mechanical durability while the porous coating provides chemical resistance to oxidized gas and moisture, resolving the contradiction between strength and reliability.
2Duration of action of stationary object
If the anti-wearing property is enhanced, then durability is improved, but refreshing of the surface is less liable to be made, leading to image deletion
Solution Approach 1:
The porous coating layer provides a surface structure that facilitates refreshing by allowing easy removal of deteriorated materials and adsorbed substances. The porous structure maintains durability through its inherent resistance to wear while enabling periodic regeneration of the surface properties, thus preventing image deletion over time.
3Reliability
If recessed portions are provided on the surface, then image deletion is suppressed, but image quality lowering occurs due to improper arrangement of recessed portions
Solution Approach 1:
The invention applies recessed portions with specific arrangement patterns where the density and distribution of recessed portions vary by location. This local quality approach ensures that recessed portions effectively suppress image deletion in critical areas while maintaining image quality in other areas, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The invention uses recessed portions with controlled area ratios, applying them partially rather than uniformly across the entire surface. By optimizing the area ratio and arrangement pattern, the invention achieves sufficient image deletion suppression without excessive recessed portions that would degrade image quality.
Data Source
AI summary
In an image forming apparatus in which an electrostatic image is formed on an electrophotographic photosensitive member using at least a process of a pseudo halftone formed by dots as a method of representing gradation, the electrophotographic photosensitive member is provided on a surface thereof with a plurality of recessed portions of 0.5 μm more and 5 μm or less in depth and 20 μm or more and 80 μm or less in longest diameter of an opening, when a square region of 500 μm×500 μm is arbitrarily extracted on the surface of the electrophotographic photosensitive member, in the square region, a total area of the recessed portions is 10000 μm2 or more and 90000 μm2 or less and a total area of a flat portion contained in a portion other than the recessed portion is 80000 μm2 or more and 240000 μm2 or less, and an arrangement (A) of the plurality of recessed portions is such an arrangement that an image quality lowering index (f) calculated by specific processing is 14% or less.