Doped Tin Oxide Conductive Layer for Photosensitive Member
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Solution Overview
Problem
Electrophotographic photosensitive members with conductive layers containing metal oxide particles suffer from increased residual potential, pattern memory, and crack formation, which affect image quality and reliability in high-speed electrophotographic apparatuses.
Innovation Solution
A conductive layer comprising zinc oxide and tin oxide particles, with specific doping elements and ratios, is used to suppress residual potential, pattern memory, and crack formation, ensuring a stable conductive path and improved image output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive layer containing metal oxide particles is used, then the photosensitive layer is protected from electrical breakdown, but the potential of the conductive layer easily varies due to environmental changes in temperature and humidity
Solution Approach 1:
The patent changes the chemical composition parameters of the metal oxide particles by introducing specific dopants (antimony, tungsten, molybdenum, or niobium) into the tin oxide structure. This doping modifies the electrical and environmental stability characteristics of the conductive layer, making the potential less sensitive to temperature and humidity variations while maintaining protective function.
Solution Approach 2:
The patent creates a composite conductive layer by combining tin oxide particles with zinc oxide particles at a specific weight ratio (70:30 to 90:10). This composite structure leverages the complementary properties of both metal oxides to achieve both electrical breakdown protection and potential stability against environmental changes.
2Productivity
If high-speed electrophotographic apparatuses are used to output a large number of identical images within a short time, then productivity increases, but image defects called pattern memory are easily caused
Solution Approach 1:
The patent modifies the electrical parameters of the conductive layer through metal oxide doping, which improves charge dissipation characteristics. This enables the system to handle high-speed operation without accumulating residual charges that would cause pattern memory defects, thus maintaining image quality at high productivity levels.
3Reliability
If the conductive layer contains metal oxide particles, then surface defects of the support are covered, but cracks in the conductive layer and increase in residual potential occur
Solution Approach 1:
The patent uses a composite of tin oxide and zinc oxide particles with optimized weight ratio and particle size distribution. This composite structure provides both adequate coverage of surface defects and sufficient mechanical flexibility to prevent crack formation during the coating process and subsequent handling.
Solution Approach 2:
The patent specifies different particle size ranges for the metal oxide particles (0.01 μm to 1 μm) to optimize both coverage of surface defects and prevention of cracks. The local quality of the particle distribution is controlled to ensure proper adhesion and flexibility of the conductive layer.
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 residual potential, minimizes pattern memory, and prevents crack formation in the conductive layer, enhancing the reliability and quality of images produced by electrophotographic apparatuses.
Implementation Method 1
a conductive layer on the support; wherein the conductive layer contains: a binder material; a first metal oxide particle; and a second metal oxide particle, the first metal oxide particle is a zinc oxide particle coated with tin oxide doped with either one element of phosphorus, tungsten, niobium, tantalum, and fluorine or a tin oxide particle coated with tin oxide doped with either one element of phosphorus, tungsten, niobium, tantalum, and fluorine
Data Source
AI summary
A conductive layer of an electrophotographic photosensitive member contains a first metal oxide particle, a second metal oxide particle, and a binder material. The first metal oxide particle is a zinc oxide particle or tin oxide particle coated with tin oxide doped with phosphorus, tungsten, fluorine, niobium, or tantalum, and the second metal oxide particle is a tin oxide particle doped with an element selected from the group consisting of phosphorus, tungsten, fluorine, niobium, and tantalum, the element being the same as the element with which the tin oxide of the first metal oxide particle is doped. The conductive layer satisfies formulae (1) and (2)2≦{(V2/VT)/(V1/VT)}×100≦25 formulae (1):15≦{(V1/VT)+(V2/VT)}×100≦45 formulae (2).