Image Bearing Member Crosslinked Surface Layer Thermal Curing
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Solution Overview
Problem
Existing image bearing members with organic photoconductors face challenges in combining high anti-abrasion properties with stable electric characteristics and environmental adaptability, particularly due to the deterioration of charge transport materials under ultraviolet irradiation and environmental changes.
Innovation Solution
A crosslinked surface layer is formed using a specific radical reactive compound with a structure represented by Chemical Formula A, which includes a charge transport curing compound that maintains anti-abrasion properties and stability under varying environmental conditions, including humidity and temperature, by incorporating a monomer with multiple polymerizable function groups and a polymerization initiator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cross linking surface layer is formed by optical curing using ultraviolet light, then anti-abrasion properties are improved, but charge transport materials are dissembled and deteriorated
Solution Approach 1:
The patent changes the curing method from optical curing (ultraviolet light) to thermal curing (heat treatment at 80-200°C for 1-24 hours). This parameter change eliminates the disassembly of charge transport materials while still achieving cross-linking to improve anti-abrasion properties. The thermal curing process forms a dense three-dimensional network structure without the harmful effects of ultraviolet irradiation.
Solution Approach 2:
The patent replaces the optical curing system (ultraviolet light source, photo-initiators) with a thermal curing system (heat treatment). This substitution eliminates the photodissociation of charge transport materials while maintaining the cross-linking function. The thermal energy induces curing reactions without the mechanical disruption of ultraviolet light.
2Duration of action of stationary object
If the thickness of the cross linked surface layer is increased to improve anti-abrasion property, then durability is improved, but sensitivity and charge transportability deteriorate
Solution Approach 1:
The patent optimizes the thickness parameter of the cross-linked surface layer to 1-20 μm, which is sufficient to provide durability while maintaining charge transportability. Additionally, the patent changes the curing method to thermal curing, which creates a more uniform and controlled cross-linking structure that preserves electrical properties even at higher thicknesses.
Solution Approach 2:
The patent uses composite materials consisting of a charge transport curing compound (containing polymerizable function groups) combined with a monomer having multiple function groups. This composite structure creates a cross-linked network that maintains both mechanical strength and charge transport properties, allowing for thicker layers without sacrificing sensitivity.
3Strength
If a charge transport material with polymerizable function groups is used to form cross linking structure, then anti-abrasion property is improved, but the material is dissembled by ultraviolet irradiation
Solution Approach 1:
The patent replaces ultraviolet irradiation with thermal curing to initiate polymerization. This substitution prevents photodissociation of the charge transport material while still achieving cross-linking. The thermal energy activates the polymerizable function groups without breaking the molecular structure of the charge transport material.
Solution Approach 2:
The patent changes the curing condition from optical (ultraviolet) to thermal (heat treatment at 80-200°C). This parameter change fundamentally alters the curing mechanism to one that does not involve photodissociation. The thermal curing process forms stable cross-links without decomposing the charge transport material's molecular structure.
4Reliability
If conventional organic photoconductors are used to achieve high sensitivity, then electric characteristics are improved, but the material is easily abraded under mechanical stress
Solution Approach 1:
The patent creates a composite structure by incorporating a cross-linked surface layer containing a charge transport curing compound with the conventional organic photoconductor. This composite structure combines the high sensitivity of the organic photoconductor with the abrasion resistance of the cross-linked network. The cross-linked layer acts as a protective barrier while maintaining charge transport capability.
Solution Approach 2:
The patent applies cross-linking specifically to the surface layer of the organic photoconductor, creating a localized region with enhanced mechanical strength. This local quality change provides abrasion resistance at the surface where mechanical stress occurs, while the bulk material maintains its charge transport properties. The cross-linked network is concentrated where it is most needed for protection.
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 provides an image bearing member with enhanced anti-abrasion properties and stable electric characteristics, reducing image density variations and maintaining image quality over an extended period, even when exposed to oxidizing gases like ozone and nitrogen oxides.
Implementation Method 1
a cross linking surface layer is formed by optical curing, irradiation of light is greatly influential. In general, ultraviolet is used as a light source for optical curing.
Data Source
Figure 1A~2
Figure 3~4
Figure 5~6
AI summary
An image bearing member including an electroconductive substrate, a photosensitive layer located overlying the electroconductive substrate and a cross linking surface layer comprising a charge transport curing compound and located overlying the photosensitive layer, wherein the charge transport curing compound includes a material including a structure unit represented by the following Chemical formula A: where R1 to R5 and R1' to R5' independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, R6 represents a hydrogen atom or a methyl group and X represents an alkylene group having a straight chain or a branched chain having 2 to 5 carbon atoms.