Undercoat Layer Resistivity Control for Electrophotographic Photosensitive Members
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Solution Overview
Problem
Electrophotographic photosensitive members with zinc oxide particles in the undercoat layer face issues of ghosting, changes in light-area potential, and black dots due to high powder resistance, while titanium oxide particles cause charge storage and visibility of support defects.
Innovation Solution
Incorporating titanium oxide particles coated with tin oxide, doped with elements like zinc, aluminum, fluorine, tungsten, niobium, or tantalum, and oxygen-deficient tin oxide into the undercoat layer, with a volume resistivity range of 1×10^10 to 1×10^13 Ω·cm, and a content of 3% to 20% by mass, to suppress charge injection and improve conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zinc oxide particles are used in the undercoat layer to suppress charge storage, then charge suppression is improved, but ghosting and changes in light-area potential occur due to high powder resistance
Solution Approach 1:
The patent combines zinc oxide particles with titanium oxide particles coated with tin oxide in the undercoat layer. The zinc oxide particles provide charge suppression, while the titanium oxide particles with tin oxide coating provide low powder resistance and high transparency, creating a composite material system that achieves both charge suppression and prevents ghosting and light-area potential changes
Solution Approach 2:
The patent controls the volume resistivity of the undercoat layer to be within 1×10^10 to 1×10^13 Ω·cm by adjusting the particle composition and ratios. This parameter control ensures that the undercoat layer has sufficient charge suppression capability while maintaining low enough resistance to prevent ghosting and potential changes
2Reliability
If the content of zinc oxide particles is increased to improve charge suppression, then charge suppression is improved, but cracks occur in the undercoat layer
Solution Approach 1:
The patent creates a composite undercoat layer containing both zinc oxide particles and titanium oxide particles coated with tin oxide. This composite structure allows for optimal particle distribution and interaction, improving charge suppression while the tin oxide coating on titanium oxide particles prevents excessive stress concentration that would cause cracking
Solution Approach 2:
The patent uses different particle types with specific local functions: zinc oxide particles for charge suppression and titanium oxide particles with tin oxide coating for structural integrity and transparency. The local quality of each particle type is optimized for its specific function while contributing to overall layer stability
3Object-affected harmful factors
If titanium oxide particles are used to conceal support defects, then transparency is improved, but charge storage occurs due to high powder resistance
Solution Approach 1:
The patent combines titanium oxide particles with zinc oxide particles in the undercoat layer. The titanium oxide particles provide high transparency to conceal support defects, while the zinc oxide particles provide charge suppression capability, creating a balanced composite material that achieves both transparency and charge management
Solution Approach 2:
The patent controls the volume resistivity parameter of the undercoat layer to be within 1×10^10 to 1×10^13 Ω·cm by adjusting the composition ratios of titanium oxide and zinc oxide particles. This parameter control ensures that the layer has sufficient transparency while maintaining appropriate charge suppression without excessive charge storage
4Reliability
If charge flows into titanium oxide particles, then charge storage is reduced, but excessive current flows into zinc oxide particles causing black dots
Solution Approach 1:
The patent creates a composite particle system where titanium oxide particles with tin oxide coating serve as charge transport pathways, while zinc oxide particles provide charge suppression. The tin oxide coating on titanium oxide particles facilitates controlled charge flow, preventing excessive current concentration that would cause black dots
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
This configuration effectively reduces changes in light-area potential and black dots, while concealing support defects, maintaining chargeability and preventing excessive current flow.
Implementation Method 1
the undercoat layer has a volume resistivity of from 1×10^10 Ω·cm to 1×10^13 Ω·cm
Implementation Method 2
zinc oxide particles can be preferably used as the metal oxide particles in the undercoat layer in view of electric characteristics such as volume resistivity and dielectric constant
Implementation Method 3
at least one particle selected from titanium oxide particles coated with tin oxide doped with any one of zinc, aluminum, fluorine, tungsten, niobium, tantalum, and phosphorus
Data Source
AI summary
An electrophotographic photosensitive member includes an undercoat layer, the undercoat layer having a volume resistivity of from 1×1010 Ω·cm to 1×1013 Ω·cm, the undercoat layer contains (A) a zinc oxide particle and (B) at least one particle selected from titanium oxide particles coated with tin oxide doped with any one of zinc, aluminum, fluorine, tungsten, niobium, tantalum, and phosphorus and a titanium oxide particle coated with oxygen deficient tin oxide, and the content of the particle (B) in the undercoat layer is from 3% by mass to 20% by mass based on the content of the particle (A).