Photosensitive Member Protection Layer for Discharge Smear Control
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Solution Overview
Problem
Existing electrophotographic photosensitive members suffer from image smearing due to low surface resistance and discharge products, which are exacerbated by improved mechanical durability, and existing additives fail to sufficiently suppress this issue.
Innovation Solution
Incorporating a protection layer with 40 to 70 vol% niobium-containing titanium oxide particles and a volume resistivity of 1.0 × 10^9 to 1.0 × 10^14 Ω·cm to enhance charge retention and reduce discharge products, thereby suppressing image smearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mechanical durability (abrasion resistance) of the electrophotographic photosensitive member is improved, then the lifespan is extended, but discharge products remain on the surface causing image smearing
Solution Approach 1:
The invention changes the surface resistance parameter of the photosensitive member by incorporating electroconductive particles in a protection layer, achieving a surface resistance of 1.0×10^9 to 1.0×10^14 Ω·cm. This parameter modification allows the surface to maintain high abrasion resistance while suppressing image smearing through controlled electrical properties that prevent discharge product accumulation
Solution Approach 2:
The invention uses a composite protection layer containing electroconductive particles (such as metal oxides or carbon black) combined with a resin binder. This composite structure provides both mechanical durability from the resin matrix and electrical conductivity from the dispersed particles, resolving the contradiction between durability and smearing prevention
2Reliability
If the surface resistance is low due to moisture adsorption, then the surface becomes more conductive, but image smearing occurs due to discharge products
Solution Approach 1:
The invention modifies the surface resistance parameter to a specific range (1.0×10^9 to 1.0×10^14 Ω·cm) that balances charge retention and smearing prevention. This controlled resistance level prevents excessive charge leakage while avoiding the accumulation of discharge products that cause smearing, unlike conventional surfaces with uncontrolled low resistance
3Object-generated harmful factors
If existing additives (alkylamine or urea polymer) are added to the surface layer, then some suppression of image smearing is achieved, but smearing is not sufficiently suppressed during electrophotographic process
Solution Approach 1:
The invention changes the fundamental approach from adding chemical additives to modifying the electrical parameter (surface resistance) of the surface layer. By controlling the surface resistance through electroconductive particles, the invention achieves superior smearing suppression compared to additive-based methods, which only provide partial suppression
Solution Approach 2:
The invention replaces the chemical approach (using additives like alkylamine or urea polymer) with an electrical/physical approach (controlling surface resistance through electroconductive particles). This substitution provides more effective and reliable smearing suppression during the electrophotographic process
Data Source
Figure 1~2
AI summary
Provided is an electrophotographic photosensitive member including an electroconductive support, a photosensitive layer, and a protection layer, wherein the protection layer contains electroconductive particles, a content of the electroconductive particles in the protection layer is 40 to 70 vol%, and a volume resistivity of the protection layer is 1.0 × 109 to 1.0 × 1014 Ω·cm.