Electrophotographic Photoreceptor Undercoat Layer Thickness and Roughness Control
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Solution Overview
Problem
The degradation of image graininess in electrophotographic photoreceptors due to micro unevenness on the surface of conductive substrates, which affects the quality of halftone and gradation images, is not effectively addressed by existing technologies.
Innovation Solution
An electrophotographic photoreceptor with a conductive substrate and an undercoat layer having a thickness of 10 μm or greater, where the integrated value of intensity in a specific power spectrum range of the substrate's roughness curve is between 0.02 and 0.10, and optionally containing metal oxide particles, to minimize surface unevenness and enhance image graininess.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the undercoat layer thickness is increased to 10 μm or greater, then image graininess is improved, but manufacturing cost and material consumption increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the undercoat layer, specifically setting the thickness to 10 μm or greater and incorporating metal oxide particles with specific properties (average particle diameter 1 μm or less, refractive index 1.5 or greater). These parameter changes optimize the layer's ability to mask substrate unevenness while controlling material usage efficiency.
Solution Approach 2:
The undercoat layer is formulated as a composite material containing binder resin and metal oxide particles. This composite structure combines the adhesive and structural properties of the binder resin with the optical and surface-leveling properties of the metal oxide particles, achieving improved image graininess through synergistic material interaction.
2Manufacturing precision
If metal oxide particles are added to the undercoat layer to reduce surface unevenness, then image quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by incorporating metal oxide particles with specific local properties (high refractive index of 1.5 or greater, small particle size of 1 μm or less) into the undercoat layer. These particles are strategically selected to address the specific problem of surface unevenness and light scattering at the micro-level, improving image quality without requiring complex manufacturing interventions.
3Manufacturing precision
If the undercoat layer thickness is increased to mask substrate defects, then image graininess improves, but production efficiency decreases
Solution Approach 1:
The patent optimizes the thickness parameter of the undercoat layer to 10 μm or greater, which provides sufficient coverage to mask substrate defects and improve image graininess. This parameter is carefully selected to achieve the minimum effective thickness that balances image quality improvement with reasonable production efficiency, avoiding excessive material usage and processing time.
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 proposed solution effectively reduces surface unevenness, resulting in improved image graininess and quality, particularly in halftone and gradation images, by ensuring the undercoat layer thickness and composition effectively mitigate substrate-induced defects.
Implementation Method 1
the undercoat layer has a layer thickness of 10 μm or greater... effectively reduces surface unevenness, resulting in improved image graininess
Implementation Method 2
an integrated value of an intensity in a period range of 0.01 mm or greater and 0.1 mm or less in a power spectrum obtained by performing fast Fourier transform on a roughness curve
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, in which an integrated value of an intensity in a period range of 0.01 mm or greater and 0.1 mm or less in a power spectrum obtained by performing fast Fourier transform on a roughness curve of an outer peripheral surface of the conductive substrate in an axial direction is 0.02 or greater and 0.10 or less, and the undercoat layer has a layer thickness of 10 μm or greater.