Electrophotographic Photoconductor Undercoat Resistivity Control
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Solution Overview
Problem
Existing electrophotographic photoconductors face challenges in maintaining electrostatic property stability and preventing residual image defects due to the degradation of organic compounds in the undercoat and photoconductive layers, particularly when there are discrepancies in the HOMO levels of charge generating and transport materials, and poor charge transport properties.
Innovation Solution
An electrophotographic photoconductor configuration with a conductive support, an undercoat layer containing metal oxide particles, a binder, and a salicylic acid derivative, where the metal oxide particles have a volume resistivity of 1×10^5 Ω·cm to 1×10^8 Ω·cm and a thickness of 2 to 20 micrometers, and the salicylic acid derivative stabilizes the dispersion and electric properties, promoting n-type semiconductivity and charge transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydroxyanthraquinone-based compounds or aminohydroxyanthraquinone-based compounds are attached to metal oxide particles to improve charge transport property, then electrostatic property stability is improved, but the metal oxide particles aggregate and dispersion uniformity deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the acceptor compound by specifying precise HOMO levels (−5.0 eV to −6.0 eV) and introducing specific molecular structures (formula 1 with defined groups). This parameter optimization prevents aggregation while maintaining electrostatic property stability.
Solution Approach 2:
The patent creates a composite material system combining metal oxide particles with specifically designed acceptor compounds (formula 1) and coupling agents. This composite approach achieves both stable electrostatic properties and uniform dispersion by leveraging the synergistic effects of multiple components.
2Ease of operation
If the HOMO level of charge generating material is adjusted to improve charge injection, then charging property is improved, but electrostatic property stability deteriorates due to HOMO level discrepancy with charge transport material
Solution Approach 1:
The patent optimizes the HOMO level parameter of the charge generating material to a specific range (−5.0 eV to −6.0 eV) that balances charge injection efficiency with electrostatic property stability, preventing discrepancies that cause degradation.
Solution Approach 2:
The patent introduces an acceptor compound as an intermediary between the charge generating layer and charge transport layer. This intermediary material mediates the energy transfer and maintains stable electrostatic properties while enabling effective charge injection.
3Reliability
If undercoat layer thickness is increased to improve charge transport, then electrostatic property stability is improved, but manufacturing complexity and material usage increase
Solution Approach 1:
The patent optimizes the undercoat layer thickness parameter to a specific range (2 μm to 20 μm) that achieves sufficient electrostatic property stability while minimizing material usage. The specific resistivity range (1×10^5 to 1×10^8 Ω·cm) is also optimized to reduce material quantity.
Solution Approach 2:
The patent applies different material compositions and properties to different regions of the undercoat layer. By using metal oxide particles with specific acceptor compounds and coupling agents, the layer achieves localized optimization of charge transport and electrostatic stability without requiring excessive thickness.
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 ensures high electrostatic property stability and minimizes residual image defects, enabling long-term stable image output by adjusting the volume resistivity and charge transport properties of the undercoat layer.
Implementation Method 1
the salicylic acid derivative stabilizes the dispersion and electric properties, promoting n-type semiconductivity and charge transport
Implementation Method 2
the metal oxide particles have a volume resistivity of 1×10^5 Ω·cm to 1×10^8 Ω·cm
Implementation Method 3
the undercoat layer has good charge transport properties... the charge transport function of each layer and the charge injecting property at the interface of each layer
Data Source
AI summary
Provided is an electrophotographic photoconductor including: a conductive support; an undercoat layer; and a photoconductive layer, wherein the undercoat layer and the photoconductive layer are provided over the conductive support in the order of reciting, wherein the undercoat layer contains at least metal oxide particles, a binder, and a salicylic acid derivative such as 4-methylsalicylic acid, wherein the metal oxide particles have a volume resistivity of 1×105 Ω·cm or higher but 1×108 Ω·cm or lower, wherein the undercoat layer has a volume resistivity of 0.001×106 Ω·cm or higher but 0.02×106 Ω·cm or lower, and wherein the undercoat layer has a thickness of 2 micrometers or greater but 20 micrometers or less.