Electrophotographic Photoreceptor Outermost Layer Durability
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Solution Overview
Problem
Existing electrophotographic photoreceptors face challenges in maintaining image quality due to surface deterioration from electrical stress and moisture, leading to adsorption of ionic materials and reduced surface resistance, which affects the longevity and quality of printed images.
Innovation Solution
An electrophotographic photoreceptor with an outermost layer comprising a cured film of a composition containing a charge transporting compound with specific structural units and a polycarbonate resin, optimizing the absorption peak intensity ratio and width to enhance electrical characteristics and mechanical strength, thereby controlling the viscosity and thickness of the layer for improved durability and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer based on acrylic materials is used, then mechanical strength is improved, but image quality deteriorates due to surface deterioration from electrical stress and moisture
Solution Approach 1:
The patent uses a composite material system consisting of a photoreceptor layer containing charge transporting compounds and a protective layer containing acrylic resin. This composite structure allows the photoreceptor layer to maintain electrical characteristics for image quality while the protective layer provides mechanical strength and environmental protection. The specific structural requirements for the charge transporting compound (including the R-O-CO-CR'=CH-R'' unit with controlled IA/IC ratio and width at half maximum) ensure optimal performance in this composite configuration.
2Strength
If the outermost layer is made thicker to improve durability, then mechanical strength is improved, but surface resistance decreases leading to adsorption of ionic materials
Solution Approach 1:
The patent optimizes the thickness and composition parameters of the outermost layer by controlling the absorption peak intensity ratio (IA/IC) of the charge transporting compound and ensuring the width at half maximum is 25 cm⁻¹ or more. These parameter adjustments allow the layer to achieve optimal balance between mechanical durability and electrical properties, preventing surface resistance degradation while maintaining adequate thickness for protection.
3Reliability
If charge transporting compound and polycarbonate resin are mixed to improve miscibility, then electrical characteristics are improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent establishes specific parameter ranges for the charge transporting compound (IA/IC ratio of 0.5 to 10 and width at half maximum of 25 cm⁻¹ or more) that optimize both electrical characteristics and manufacturing controllability. These parameter specifications ensure adequate miscibility between the charge transporting compound and polycarbonate resin while maintaining layer thickness within controllable manufacturing tolerances.
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 results in an electrophotographic photoreceptor with enhanced electrical characteristics, mechanical strength, and controlled film thickness, reducing image degradation and extending the photoreceptor's lifespan by inhibiting surface roughness and improving miscibility between the charge transporting compound and polycarbonate resin.
Implementation Method 1
an outermost layer of the electrophotographic photoreceptor including a cured film of a composition which includes at least one charge transporting compound (a) having a charge transporting skeleton and at least two structural units represented by R—O—CO—CR′═CH—R′′ in the same molecule
Implementation Method 2
a ratio (IA/IC) of an absorption peak intensity (IA) resulting from stretching vibration of a carbonyl group originating from the structural unit represented by R—O—CO—CR′═CH—R′′ of the charge transporting compound (a) to an absorption peak intensity (IC) resulting from stretching vibration of a carbonyl group originating from the polycarbonate resin in an IR absorption spectrum
Data Source
AI summary
The present invention provides an electrophotographic photoreceptor including a photosensitive layer on a conductive substrate, an outermost layer of the electrophotographic photoreceptor including a cured film of a composition which includes at least one charge transporting compound (a) having a charge transporting skeleton and at least two structural units represented by R—O—CO—CR′═CH—R″ in the same molecule, and at least one polycarbonate resin; a ratio (IA/IC) of an absorption peak intensity (IA) resulting from stretching vibration of a carbonyl group originating from the structural unit represented by R—O—CO—CR′═CH—R″ of the charge transporting compound (a) to an absorption peak intensity (IC) resulting from stretching vibration of a carbonyl group originating from the polycarbonate resin in an IR absorption spectrum of the outermost layer being from about 0.5 to about 10, and a width at half maximum of the absorption peak of the absorption peak intensity (IA) being about 25 cm−1 or more.