Photoconductive Layer Abrasion Control via Developer Length Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrophotographic image forming apparatuses with rigid photosensitive members, the contact development method leads to abrasion of the photoconductive layer at the interface with the developer carrying member, causing leakage and defective images due to direct friction in areas without developer interposition, which is not adequately addressed by existing seal methods.
Innovation Solution
The solution involves optimizing the length relationship between the developer carrying member and the cleaning blade, where the developer carrying member's length is set to be greater than the cleaning blade's length, ensuring that abrasion dust acts as a buffer and is not cleaned off, thereby reducing abrasion and maintaining dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning blade length is made equal to or longer than the developer carrying member length to ensure complete cleaning, then cleaning performance is improved, but abrasion of the photoconductive layer increases due to direct friction without developer buffer
Solution Approach 1:
The invention applies different functional zones along the longitudinal direction: the developer carrying member has a developer coat area for image formation and a developer non-coat area for buffer function, while the cleaning blade is positioned to clean only the developer coat area. This local differentiation allows the photoconductive layer to be protected from abrasion in the non-coat area while maintaining cleaning effectiveness in the coat area.
Solution Approach 2:
Instead of making the cleaning blade longer than the developer carrying member to ensure complete cleaning (conventional approach), the invention inverts this logic by making the developer carrying member longer than the cleaning blade. This inversion allows the developer non-coat area to extend beyond the cleaning blade, creating a buffer zone that prevents abrasion while the cleaning blade still effectively cleans the developer coat area.
2Object-affected harmful factors
If the developer carrying member length is made greater than the cleaning blade length to create a buffer zone, then abrasion is reduced, but cleaning completeness may be compromised
Solution Approach 1:
The cleaning blade is positioned to clean only the developer coat area of the developer carrying member, which is the region requiring cleaning for proper image formation. The developer non-coat area, which extends beyond the cleaning blade, serves as a buffer zone that does not require cleaning. This local quality differentiation resolves the contradiction by making cleaning completeness sufficient for the functional area while protecting the buffer area from abrasion.
Solution Approach 2:
The developer carrying member is segmented into two distinct functional areas: the developer coat area (for image formation and cleaning) and the developer non-coat area (for abrasion protection). The cleaning blade is positioned to act only on the coat area, creating a functional segmentation that allows both complete cleaning where needed and abrasion protection where not needed.
3Reliability
If seal members are used to prevent developer leakage, then developer containment is improved, but assembly complexity and potential abrasion from seal contact increase
Solution Approach 1:
The invention extracts and eliminates the seal members from the conventional structure. Instead of using separate seal components to contain the developer, the invention uses the developer non-coat area itself as the containment mechanism. This extraction simplifies the overall structure by removing unnecessary seal members and their associated assembly complexity while maintaining effective developer containment through the extended non-coat area.
Data Source
AI summary
An electrophotographic image forming apparatus forming an image on a recording medium, includes: an electrophotographic photosensitive member having a photoconductive layer on a rigid base; an exposure device forming a latent image on the electrophotographic photosensitive member; a developer carrying member that carries a developer to develop the latent image using the developer in contact with the electrophotographic photosensitive member; and a cleaning blade that cleans the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, wherein the following expression is satisfied: Le≧Ldr>Lcl, where Le: a longitudinal length of the photoconductive layer Le, Ldr: a longitudinal length of the developer carrying member to be contacted with the electrophotographic photosensitive member, and Lcl: a longitudinal length of the cleaning blade to be contacted with the electrophotographic photosensitive member.