Electrophotographic Photoreceptor Surface Layer Optimization
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Solution Overview
Problem
Electrophotographic photoreceptors face challenges in achieving both excellent electrical characteristics and scratch resistance, with existing protective layers often compromising on either property due to the movement of charge transporting materials or binder resins during the coating process.
Innovation Solution
A configuration involving a conductive substrate, a charge generating layer, a charge transporting layer with a polycarbonate binder, and an outermost surface layer formed from a chain polymerizable compound with specific A and B values, determined by Attenuated total reflection Fourier transform infrared spectroscopy, to optimize the ratio of charge transporting material and polycarbonate concentration, enhancing both electrical properties and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer is formed with acrylic materials to increase strength, then scratch resistance is improved, but electrical characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the protective layer by using a cured film formed from a chain polymerizable compound with specific A and B values (A=(S1/S13)−(S0/S03), B=S2/S23) determined by ATR-FTIR spectroscopy. This parameter control optimizes both scratch resistance and electrical characteristics simultaneously
Solution Approach 2:
The protective layer is formed as a composite structure combining a chain polymerizable compound with specific functional groups and a cured film matrix. This composite approach allows simultaneous optimization of mechanical strength and electrical properties that cannot be achieved with single materials
2Reliability
If the concentration of charge transporting material is increased to improve electrical characteristics, then electrical properties are improved, but scratch resistance deteriorates
Solution Approach 1:
The patent optimizes the concentration ratio of charge transporting material to binder resin by controlling the A and B values of the chain polymerizable compound. This parameter adjustment achieves the optimal balance between electrical characteristics and scratch resistance
Solution Approach 2:
The protective layer is designed with spatially differentiated properties where the chain polymerizable compound provides electrical functionality while the cured film matrix provides mechanical strength. The specific A and B value control ensures appropriate local distribution of functional and structural components
3Strength
If the coating process is performed to form a protective layer, then scratch resistance is improved, but charge transporting material moves causing electrical characteristics to worsen
Solution Approach 1:
The patent incorporates the chain polymerizable compound into the protective layer formulation before coating, allowing it to remain in place during the coating process. The specific A and B value control prevents material migration during coating while still achieving the desired protective and electrical properties
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 configuration results in an electrophotographic photoreceptor with improved electrical characteristics and scratch resistance, stabilizing image concentration and extending the lifetime of process cartridges and image forming apparatuses.
Implementation Method 1
an outermost surface layer provided on the charge transporting layer, which is constituted with a cured film formed of a composition including a chain polymerizable compound having at least a charge transporting skeleton and a chain polymerizable functional group in the same molecule
Implementation Method 2
has an A value represented by the following equation (1) being from 0.1 to 0.3, and a B value represented by the following equation (2) being 0.02 or less, each of which is determined by an Attenuated total reflection Fourier transform infrared spectroscopy
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate; a charge generating layer provided on the conductive substrate; a charge transporting layer provided on the charge generating layer, which is configured to include a charge transporting material and a polycarbonate; and an outermost surface layer provided on the charge transporting layer, which is constituted with a cured film formed of a composition including a chain polymerizable compound having at least a charge transporting skeleton and a chain polymerizable functional group in the same molecule, and has an A value represented by the following equation (1) being from 0.1 to 0.3, and a B value represented by the following equation (2) being 0.02 or less, each of which is determined by an Attenuated total reflection Fourier transform infrared spectroscopy:A=(S1/S13)−(S0/S03) Equation (1)B=S2/S23 Equation (2).