Electrophotographic Photosensitive Member Conductive Layer Potential Stability
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Solution Overview
Problem
Conventional electrophotographic photosensitive members struggle to maintain consistent image density and color tone uniformity due to variations in light-area and residual potentials, especially during repeated image reproduction, which is exacerbated by the electrical conductivity of their conductive layers.
Innovation Solution
An electrophotographic photosensitive member with a conductive layer composed of metal oxide particles, such as aluminum-doped zinc oxide or titanium oxide coated with phosphorus- or tungsten-doped tin oxide, is developed, which has a controlled powder resistivity to minimize potential variations, ensuring stability and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive layer containing metal oxide particles is used to cover support defects, then the electrical conductivity is improved, but the light-area potential and residual potential vary during repeated image reproduction
Solution Approach 1:
The patent changes the electrical conductivity parameter of the conductive layer by controlling the type and amount of metal oxide particles used. Specifically, it employs metal oxide particles with powder resistivity of 1.0×10³Ω·cm to 1.0×10⁶Ω·cm and controls the volume resistivity of the conductive layer to be 1.0×10⁸Ω·cm to 1.0×10¹²Ω·cm, thereby reducing potential variations during repeated image reproduction while maintaining adequate conductivity for charge distribution.
Solution Approach 2:
The patent uses composite material structure by combining metal oxide particles (such as zinc oxide, tin oxide, titanium oxide) with binder resins to form the conductive layer. This composite approach allows optimization of both conductivity and potential stability properties that cannot be achieved with single materials alone.
2Ease of manufacture
If conventional conductive layers are used, then the support surface defects are covered, but the image density and color tone uniformity deteriorate during repeated image reproduction
Solution Approach 1:
The patent changes the key parameter of volume resistivity to a specific range (1.0×10⁸Ω·cm to 1.0×10¹²Ω·cm) that balances two functions: maintaining enough conductivity to cover support surface defects uniformly, while being low enough to prevent excessive charge accumulation that causes potential variations during repeated use.
Solution Approach 2:
The patent ensures consistent image reproduction by creating a conductive layer that reliably copies the same electrical characteristics across multiple imaging cycles, thereby achieving uniform image density and color tone in repeated image reproduction.
3Ease of operation
If the electrical conductivity of the conductive layer is increased, then the charge distribution is improved, but the light-area potential and residual potential variations increase
Solution Approach 1:
The patent optimizes the electrical conductivity parameter to a specific range by selecting metal oxide particles with appropriate powder resistivity (1.0×10³Ω·cm to 1.0×10⁶Ω·cm) and controlling the resulting volume resistivity (1.0×10⁸Ω·cm to 1.0×10¹²Ω·cm). This optimized parameter range provides sufficient charge distribution capability while preventing excessive charge leakage that would cause potential variations.
Solution Approach 2:
The patent applies local quality control by using metal oxide particles with specific local electrical properties (powder resistivity characteristics) that create a conductive layer with uniform but controlled conductivity throughout, ensuring consistent charging performance without localized charge accumulation or leakage.
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 provides a significant reduction in light-area and residual potential variations, enhancing the reproducibility of image density and color tone uniformity, thereby improving the overall performance and longevity of the electrophotographic photosensitive member.
Implementation Method 1
a layer containing metal oxide particles is known as the layer formed for the purpose of covering any defects of the surface of the support. The layer containing metal oxide particles commonly has a higher electrical conductivity than a layer not containing any metal oxide particles
Implementation Method 2
improving the blocking of injection of electric charges from the support into the photosensitive layer
Implementation Method 3
these are greatly influenced by the electric potential of an electrophotographic photosensitive member
Data Source
Figure 1~3
Figure 4~6
AI summary
An electrophotographic photosensitive member having a specific conductive layer and promising less variation in light-area potential and residual potential in reproducing images repeatedly, and a process cartridge and an electrophotographic apparatus which have such an electrophotographic photosensitive member are provided. Where a test in which a voltage of -1.0 kV having only a DC voltage component is continuously applied to the conductive layer for 1 hour is conducted, the conductive layer has volume resistivity satisfying the following mathematical expressions (1) and (2), as values before and after the test: -2.00 ≤ (log | ρ2| - log | ρ1|) ≤ 2.00 (1), and 1.0×108 ≤ ρ1 ≤ 2.0×1013 (2), where, in the expressions (1) and (2), ρ1 is volume resistivity (Ω. cm) of the conductive layer as measured before the test and ρ2 is volume resistivity (Ω. cm) of the conductive layer as measured after the test.