Conductive Layer for Electrophotographic Photosensitive Member
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Solution Overview
Problem
Electrophotographic photosensitive members using metal oxide particles as conductive layers are prone to black spots on images due to local charge injection from the support to the photosensitive layer, especially under high temperature and high humidity conditions.
Innovation Solution
A method for producing electrophotographic photosensitive members involves forming a conductive layer with a specific titanium oxide particle coated with phosphorus-doped tin oxide, where the surface area, particle diameter, and density satisfy the relation 45≦A×ρ×D≦65, to suppress black spots by controlling the resistance and surface characteristics of the conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a layer containing metal oxide particles is used as a conductive layer to cover defects of the support surface, then the tolerable range of support defects is widened and productivity is improved, but black spots appear on output images due to local charge injection from the support to the photosensitive layer under high temperature and high humidity conditions
Solution Approach 1:
The invention changes the electrical resistance parameter of the conductive layer by controlling the metal oxide particle properties (specifically satisfying 45≦A×ρ×D≦65). This parameter adjustment allows the layer to maintain adequate conductivity for covering support defects while reducing excessive conductivity that causes local charge injection and black spots under high temperature and humidity conditions
Solution Approach 2:
The invention uses a composite structure consisting of metal oxide particles (such as tin oxide, zinc oxide, or barium sulfate) combined with a binder resin. This composite material provides both the defect-covering conductivity and the structural stability needed to prevent black spots, balancing the competing requirements of productivity and image quality
2Manufacturing precision
If the film thickness of the conductive layer is increased to cover support defects, then the tolerable range of support defects is widened, but residual potential increases and black spots are more likely to occur
Solution Approach 1:
Instead of increasing film thickness, the invention changes the electrical resistance parameter by controlling metal oxide particle properties (satisfying 45≦A×ρ×D≦65). This allows achieving adequate defect coverage with thinner films that do not accumulate excessive residual potential or cause black spots
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces the occurrence of black spots on output images by optimizing the conductive layer's properties, ensuring stable image formation even under challenging environmental conditions.
Implementation Method 1
a layer containing metal oxide particles has a higher conductivity than that of a layer containing no metal oxide particles
Implementation Method 2
tin oxide particles doped with phosphorus
Implementation Method 3
Such a highly conductive layer is provided between the support and the photosensitive layer to cover the defects of the surface of the support
Data Source
AI summary
An electrophotographic photosensitive member is provided in which black spots on an output image are hardly caused by local charge injection from a support to a photosensitive layer. For this purpose, a conductive layer is formed using a coating liquid for a conductive layer prepared using a solvent, a binder material and a metal oxide particle that satisfies the following relation (i): 45≦A×ρ×D≦65 (i) wherein A denotes the surface area of the metal oxide particle per unit mass [m2/g], D denotes the number average particle diameter of the metal oxide particle [μm], and ρ denotes the density of the metal oxide particle [g/cm3]. The metal oxide particle is a titanium oxide particle coated with tin oxide doped with phosphorus.