Electrophotographic Photoreceptor Outermost Layer Crosslinking
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Solution Overview
Problem
Electrophotographic photoreceptors face challenges in maintaining mechanical strength and stable electric characteristics over long periods, particularly due to issues with uneven curing and surface roughness caused by highly reactive acryl groups in triphenylamine structures, leading to image unevenness and reduced durability.
Innovation Solution
A cured film composition containing a compound with a triphenylamine structure and four or more methacryloyl groups is used as the outermost layer, which provides high crosslinking density and mechanical strength, and is formed through thermal curing without a polymerization initiator, allowing for simultaneous application of heat and light energy to ensure thorough curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer with highly reactive acryl groups is used to improve mechanical strength, then the mechanical strength is improved, but uneven curing and surface roughness occur leading to image unevenness
Solution Approach 1:
The patent changes the chemical structure parameter from highly reactive acryl groups (C=C) to less reactive methacryloyl groups (C=C with additional carbonyl), and further to compounds with four or more methacryloyl groups. This parameter change reduces the reactivity difference between curing and imaging processes, eliminating surface roughness and uneven curing while maintaining mechanical strength through high crosslinking density achieved by the multi-functional methacryloyl groups.
2Reliability
If thermal curing is applied to ensure thorough curing without polymerization initiator, then curing completeness is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the chemical initiation system (polymerization initiators) with a physical activation method (thermal curing). By using heat energy to directly activate the methacryloyl groups for crosslinking, the system eliminates the need for chemical initiators while achieving thorough curing. The energy input is controlled and efficient, converting thermal energy directly into chemical bond formation without intermediate chemical decomposition steps.
3Duration of action of stationary object
If high crosslinking density is achieved to improve mechanical strength, then durability is improved, but curing uniformity deteriorates due to excessive reactivity
Solution Approach 1:
The patent achieves high crosslinking density (improving durability) by using compounds with four or more methacryloyl groups per molecule, while maintaining curing uniformity by selecting methacryloyl groups with moderate reactivity. The multi-functional structure allows multiple crosslinking points per molecule, creating a dense network, while the controlled reactivity of methacryloyl groups ensures uniform reaction progression throughout the protective layer during thermal curing.
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 mechanical strength, improved surface properties, and stable electric characteristics, capable of withstanding repeated use without significant degradation in image quality.
Implementation Method 1
a cured film of a composition containing at least one compound (a) having a triphenylamine structure and four or more methacryloyl groups in one and the same molecule
Implementation Method 2
which provides high crosslinking density and mechanical strength
Implementation Method 3
simultaneous application of heat and light energy to ensure thorough curing
Implementation Method 4
simultaneous application of heat and light energy to ensure thorough curing
Data Source
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AI summary
The invention provides an electrophotographic photoreceptor having comprising at least an electrically conductive substrate and a photo-sensitive layer provided on the conductive substrate, the outermost layer is being a cured film of comprising a composition containing at least one compound (a) having a triphenylamine structure and four or more methacryloyl groups in one and the same molecule.