Oxazole-Modified Photoconductor Protective Layer
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Solution Overview
Problem
Electrophotographic photoconductors with three-dimensionally crosslinked protective layers face issues with charge transportability, mechanical strength, and image quality due to decomposition and nonuniformity caused by active energy beam irradiation, which conventional additives like ultraviolet ray absorbers and singlet oxygen quenchers fail to address effectively.
Innovation Solution
Incorporating a specific oxazole compound into the protective layer of the photoconductor, which suppresses the decomposition of charge-transporting compounds during irradiation, maintaining electric and mechanical properties and reducing charge trapping, thereby enhancing charge transportability and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a three-dimensionally crosslinked protective layer is formed by irradiating a radical polymerizable charge-transporting compound with active energy beam, then scratch resistance and abrasion resistance are improved, but charge transportability degrades due to decomposition of the charge-transporting compound
Solution Approach 1:
The patent introduces a photopolymerization initiator as an intermediary substance that enables crosslinking through a different mechanism. Instead of directly exciting the charge-transporting compound, the photopolymerization initiator absorbs UV light and generates radicals that initiate polymerization of the charge-transporting compound, thereby preventing direct decomposition while achieving crosslinked structure formation
Solution Approach 2:
The patent changes the irradiation parameters by using UV light with specific wavelength ranges (300-400nm) and controlling irradiation dose, combined with changing the chemical state of the protective layer from linear to crosslinked structure through controlled photopolymerization, thereby achieving both durability and charge transportability
2Stability of the object's composition
If conventional ultraviolet ray absorbers or singlet oxygen quenchers are added to suppress decomposition, then stability is improved, but charge transportability and crosslink density are degraded
Solution Approach 1:
The patent extracts and eliminates conventional additives like ultraviolet ray absorbers and singlet oxygen quenchers from the system, replacing them with a photopolymerization initiator that performs the protective function without interfering with charge transport or crosslinking efficiency
Solution Approach 2:
The patent changes the chemical composition parameters by removing traditional stabilizers and introducing a photopolymerization initiator, thereby altering the mechanism from passive protection to active controlled crosslinking that preserves charge transportability
3Strength
If high crosslink density is achieved through direct excitation, then mechanical strength is improved, but in-plane nonuniformity increases due to nonuniform decomposition
Solution Approach 1:
The photopolymerization initiator acts as a spatially distributed intermediary that uniformly absorbs UV energy throughout the protective layer and converts it to chemical energy for crosslinking, ensuring uniform crosslink density and eliminating in-plane nonuniformity
Solution Approach 2:
The patent replaces the direct photochemical excitation mechanism with a radical polymerization mechanism initiated by photopolymerization initiators, substituting a non-uniform direct excitation process with a uniform radical chain reaction that proceeds throughout the material
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 use of an oxazole compound in the protective layer of electrophotographic photoconductors improves charge transportability, reduces potential variations, and achieves high-quality image output with reduced in-plane nonuniformity and extended operating life, meeting the demands of commercial printing.
Implementation Method 1
suppresses the decomposition of charge-transporting compounds during irradiation
Implementation Method 2
enhancing charge transportability
Implementation Method 3
obtained through chain polymerization of at least a radical polymerizable hole-transporting compound by irradiating the radical polymerizable hole-transporting compound with an active energy beam
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
An electrophotographic photoconductor including a conductive support, a charge generating layer, a hole transporting layer, and a hole transporting-protective layer, these layers being laminated in this order on the conductive support, wherein the hole transporting-protective layer contains a three-dimensionally crosslinked product which is obtained through chain polymerization of at least a radical polymerizable hole-transporting compound by irradiating the radical polymerizable hole-transporting compound with an active energy beam, and wherein the hole transporting-protective layer contains an oxazole compound represented by General Formula (1) or (2) below: