Electrophotographic Photosensitive Member Protective Layer Film Exfoliation
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Solution Overview
Problem
Electrophotographic photosensitive members experience film exfoliation due to large differences in elastic deformation rates between the protective and charge transport layers, leading to reduced durability and increased stress distortion, which existing solutions like Japanese Patent Applications Laid-Open No. 2010-66672 and No. 2017-161718 are insufficient to address effectively.
Innovation Solution
A single-layer protective layer structure represented by specific formulas, with a mass ratio of 20% to 240% based on another structure, is used, where the A value determined by total reflection Fourier transform infrared spectroscopy under specific conditions is controlled within certain ranges to reduce elastic modulus differences and enhance adhesion between layers, preventing film exfoliation while maintaining mold releasability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crosslinked cured film is used as the protective layer to improve abrasion resistance, then the durability is enhanced, but the elastic deformation rate becomes too high causing film exfoliation at the interface
Solution Approach 1:
The patent changes the chemical composition parameters of the protective layer by incorporating both acryloyloxy groups (for crosslinking and durability) and carboxyl groups (for adhesion and interface stability). This compositional parameter change allows the protective layer to achieve both high abrasion resistance and reduced elastic deformation rate, preventing film exfoliation while maintaining durability.
Solution Approach 2:
The protective layer uses a composite material system combining acryloyloxy-containing compounds (for crosslinking) and carboxyl-containing compounds (for adhesion). This composite approach allows the layer to exhibit both the durability of crosslinked structures and the interface stability provided by polar functional groups, resolving the contradiction between durability and interface stability.
2Stability of the object's composition
If the elastic deformation rate of the protective layer is increased to improve adhesion, then the interface stability is enhanced, but the abrasion resistance deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters by controlling the ratio and types of acryloyloxy groups and carboxyl groups. This parameter optimization enables the protective layer to achieve the right balance: sufficient polar functional groups for adhesion and interface stability, while maintaining crosslinked structure for abrasion resistance.
Solution Approach 2:
The protective layer employs a composite material system where acryloyloxy-containing compounds provide crosslinking for abrasion resistance, while carboxyl-containing compounds provide polar functional groups for adhesion. This composite structure simultaneously achieves both interface stability and abrasion resistance, resolving the contradiction between these two properties.
3Device complexity
If a single-layer protective layer is used to simplify the structure, then the manufacturing complexity is reduced, but the control over elastic modulus distribution becomes difficult
Solution Approach 1:
The patent uses parameter changes in the chemical composition (incorporating acryloyloxy and carboxyl groups in specific ratios) to achieve spatial variation in elastic modulus within a single-layer structure. This allows the protective layer to have different effective properties at different depths, with the composition and curing characteristics creating a gradient that improves interface adhesion while maintaining abrasion resistance, all within a simple single-layer configuration.
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 suppresses film exfoliation during long-term use by reducing elastic modulus differences and promoting interaction between the protective and charge transport layers, enhancing adhesion and durability without compromising mold releasability.
Implementation Method 1
irradiating the coated film with an electron beam
Implementation Method 2
a charge transport material having radical polymerization groups for the upper layer of the charge transport layer
Implementation Method 3
curing the coated film by heating
Data Source
AI summary
To provide an electrophotographic photosensitive member which does not cause film exfoliation in long-term use. An electrophotographic photosensitive member, having: a support; a layered photosensitive layer; and a protective layer in this order, wherein the protective layer is a single layer, the protective layer includes: at least two specific structures, the two specific structures are included in the protective layer at a mass ratio of 20% or more and 240% or less, and a peak area based on in-plane deformation vibration of terminal olefin (CH2═) of the protective layer and a peak area based on stretching vibration of C═O of acryloyloxy groups, the peak areas being determined by total reflection Fourier transform infrared spectroscopy under conditions where an internal reflection element is Ge, and an incidence angle is 45°, have a fixed relationship.