Single-Layer Photosensitive Member for Humidity Stability
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Solution Overview
Problem
Electrophotographic photosensitive members face challenges in maintaining electrostatic latent images in high temperature and humidity environments, leading to the occurrence of black spots due to moisture adherence and instability in charge transport.
Innovation Solution
A single-layer electrophotographic photosensitive member with a conductive substrate coated with an aluminum oxide film and a photosensitive layer containing an electron transport material with a reduction potential between −0.88 V and −0.66 V, which inhibits hole injection and maintains electrostatic latent images stability, reducing black spot occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer structure with charge generating layer and charge transport layer is used, then charge generation and charge transport functions are improved, but device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The patent combines the charge generating layer and charge transport layer into a single integrated photosensitive layer. This layer contains both charge generating materials (such as organic photoconductive compounds) and charge transport materials (such as hole transport materials or electron transport materials) dispersed in a binder resin, thereby performing both charge generation and charge transport functions simultaneously while simplifying the overall structure.
Solution Approach 2:
The single-layer photosensitive member is designed to perform multiple functions within one layer: charge generation through photoexcitation, charge separation, charge transport to electrodes, and image formation. This multi-functional design eliminates the need for separate specialized layers while maintaining effective electrophotographic performance.
2Device complexity
If the photosensitive layer is made thinner to reduce complexity, then manufacturing precision requirements increase, but device complexity decreases
Solution Approach 1:
The patent optimizes the thickness of the single-layer photosensitive layer to a specific range (typically 5-50 μm) to balance structural simplicity with manufacturing feasibility. This parameter optimization ensures that the layer is thin enough to maintain simplicity but thick enough to allow uniform material distribution and effective charge generation and transport, thereby reducing stringent manufacturing precision requirements.
3Adaptability or versatility
If electrophotographic photosensitive members are used in high temperature and humidity environments, then operational versatility is improved, but reliability deteriorates due to moisture adherence and charge transport instability
Solution Approach 1:
The patent employs a binder resin with specific properties (such as hydrophobicity or low moisture absorption) to create a local microenvironment within the photosensitive layer that resists moisture penetration. This localized protection at the material level prevents moisture from reaching and disrupting the charge generating and transport materials, thereby maintaining electrostatic latent image stability in humid conditions.
Solution Approach 2:
The photosensitive layer is constructed as a composite material system combining organic photoconductive compounds, charge transport materials, and specially selected binder resins. This composite structure leverages the complementary properties of each component: the photoconductive materials for charge generation, the transport materials for charge mobility, and the binder resin for structural integrity and moisture resistance, collectively enhancing environmental stability.
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 solution effectively reduces the occurrence of black spots in high temperature and humidity environments while maintaining excellent sensitivity, as evidenced by a leakage onset voltage of at least 5.0 kV and suitable electric resistance properties.
Implementation Method 1
A surface of the conductive substrate has a film of an oxide of the aluminum or a film of an oxide of the aluminum alloy
Implementation Method 2
The photosensitive layer contains an electron transport material. The electron transport material has a reduction potential of at least −0.88 V and no greater than −0.66 V versus a reference electrode (Ag/Ag+)
Implementation Method 3
The single-layer electrophotographic photosensitive member according to the aspect of the present disclosure has a leakage onset voltage of at least 5.0 kV in a high temperature and humidity environment at a temperature of 30° C. and a relative humidity of 80%
Data Source
AI summary
A single-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The conductive substrate contains aluminum or an aluminum alloy. A surface of the conductive substrate has an aluminum oxide film or an aluminum alloy oxide film. The photosensitive layer is disposed directly on the conductive substrate. The photosensitive layer contains an electron transport material. The electron transport material has a reduction potential of at least −0.88 V and no greater than −0.66 V versus a reference electrode (Ag/Ag+). The single-layer electrophotographic photosensitive member has a leakage onset voltage of at least 5.0 kV in a high temperature and humidity environment at a temperature of 30° C. and a relative humidity of 80%. The leakage onset voltage is a voltage applied to the single-layer electrophotographic photosensitive member at which current leakage starts.