Electrophotographic Photosensitive Member Protection Layer Optimization
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Solution Overview
Problem
Existing electrophotographic photosensitive members face challenges in achieving both image smearing resistance and low torque while maintaining electrophotographic characteristics, as previous technologies either improve abrasion resistance at the cost of image quality or compromise sensitivity.
Innovation Solution
An electrophotographic photosensitive member is designed with a protection layer having a specific developed area ratio (Sdr) of 1.0% to 40.0% and a peak area ratio (A value) of 0.10 to 0.27, utilizing Fourier transform infrared spectroscopy, along with the inclusion of an unsubstituted cyclohexane skeleton, triarylamine compounds, and electroconductive particles to enhance surface properties and discharge product removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a radical-polymerizable resin is used in the surface of the electrophotographic photosensitive member to improve abrasion resistance, then mechanical durability is improved, but image smearing occurs due to change in surface resistance under high-humidity environment
Solution Approach 1:
The protection layer uses a composite material system comprising a polyester resin base combined with specific additives (silane-modified polyester resin, fluorine-containing compound, and/or cyclic carbonate compound) to achieve both mechanical durability and image smearing resistance. This composite approach allows the surface to maintain structural integrity while controlling surface resistance properties.
Solution Approach 2:
The invention controls the surface resistance characteristics by adjusting the composition ratios of polyester resin units and specific additive contents (silane-modified polyester resin at 5-50 mass%, fluorine-containing compound at 1-20 mass%, cyclic carbonate compound at 1-20 mass%). These parameter adjustments enable the surface to resist both abrasion and image smearing under high-humidity conditions.
2Strength
If the surface layer is formed by polymerizing a polymerizable compound with multiple functional groups to improve scratch resistance and abrasion resistance, then mechanical durability is improved, but image smearing resistance and low torque cannot be sufficiently achieved while maintaining electrophotographic characteristic
Solution Approach 1:
The protection layer employs a composite resin system where a polyester resin (providing mechanical strength) is combined with silane-modified polyester resin, fluorine-containing compounds, and/or cyclic carbonate compounds (providing surface resistance control). This composite structure achieves scratch resistance while preventing image smearing and maintaining low torque.
Solution Approach 2:
The invention differentiates the properties within the protection layer by using polyester resin units with specific characteristics (providing base mechanical properties) combined with surface-active additives (silane-modified polyester, fluorine compounds, cyclic carbonate compounds) that specifically address surface resistance and image smearing resistance. Each component contributes locally to different functional requirements.
3Stability of the object's composition
If the surface layer is formed by polymerizing a polymerizable compound with multiple functional groups to improve crack resistance, then mechanical durability is improved, but image smearing resistance and low torque cannot be sufficiently achieved while maintaining electrophotographic characteristic
Solution Approach 1:
The protection layer uses a composite resin system where polyester resin provides crack resistance through its molecular structure, while silane-modified polyester resin, fluorine-containing compounds, and/or cyclic carbonate compounds provide surface resistance control. This composite approach simultaneously achieves crack resistance and image smearing resistance.
Solution Approach 2:
The invention adjusts the composition parameters including polyester resin molecular weight (10,000-100,000), silane-modified polyester resin content (5-50 mass%), fluorine-containing compound content (1-20 mass%), and cyclic carbonate compound content (1-20 mass%) to optimize both crack resistance and image smearing resistance while maintaining low torque.
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 achieves image smearing resistance and low torque while maintaining electrophotographic characteristics by optimizing the surface properties of the protection layer, ensuring effective removal of discharge products and maintaining sensitivity.
Implementation Method 1
peak areas of a spectrum obtained by subjecting the surface of the protection layer to measurement by a Fourier transform infrared spectroscopy total reflection method
Data Source
AI summary
An electrophotographic photosensitive member that is excellent in image smearing resistance and low torque while maintaining its electrophotographic characteristic. The electrophotographic photosensitive member is an electrophotographic photosensitive member including, in this order: a support; a photosensitive layer; and a protection layer as a surface layer, wherein the protection layer has a surface having a developed area ratio Sdr of 1.0% to 40.0%, and wherein an A value represented by the following formula (1) is 0.10 to 0.27: A=S1/S2 . . . formula (1), where, in the formula (1), S1 represents a peak area based on C═C stretching vibration of an aromatic ring by attenuated total reflection Fourier transform infrared spectroscopy, and S2 represents a peak area based on C═O stretching vibration of an ester group by the same method.