Electrophotographic Photoreceptor Coating Liquid Dispersion Stability
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Solution Overview
Problem
The challenge in producing electrophotographic photoreceptors is the poor dispersion stability of particulate silicon compounds in coating liquids, leading to aggregation and image defects such as density unevenness and colored spots, which affects the mechanical and electrical properties of the photoreceptors.
Innovation Solution
Incorporating a charge transport substance with a specific structure, a binder resin, and a particulate silicon compound, and subjecting the particulate silicon compound to surface treatment with a reactive organosilicon compound, to enhance dispersion stability without the need for additional homogenization operations, even at high particulate silicon compound concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large amount of inorganic compound is added to improve abrasion resistance, then mechanical properties are improved, but dispersion stability deteriorates causing particle aggregation
Solution Approach 1:
A dispersing agent comprising a polyester resin and an acrylic resin is introduced as an intermediary substance to mediate between the inorganic particles and the organic coating liquid. The dispersing agent adsorbs onto the inorganic particle surfaces and provides steric and electrostatic repulsion, preventing particle aggregation even at high inorganic compound concentrations (10-30 mass%). This resolves the contradiction by enabling both high abrasion resistance and stable dispersion simultaneously.
Solution Approach 2:
The invention creates a composite dispersion system combining inorganic compounds (for abrasion resistance) with a specifically formulated dispersing agent (polyester resin + acrylic resin combination). This composite approach allows the inorganic particles to be stably incorporated in high concentrations without aggregation, achieving both improved mechanical properties and maintained dispersion stability.
2Strength
If inorganic particles are added to improve mechanical properties, then abrasion resistance is improved, but image quality deteriorates due to density unevenness and colored spots
Solution Approach 1:
The dispersing agent acts as an intermediary that ensures uniform distribution of inorganic particles throughout the coating liquid. By preventing particle aggregation, the dispersing agent eliminates density unevenness and colored spots in the coated film, thereby maintaining high image quality even when inorganic particles are present at concentrations that provide sufficient abrasion resistance.
Solution Approach 2:
The invention achieves homogeneous distribution of inorganic particles through the use of the dispersing agent combination. The polyester resin and acrylic resin work together to create a uniform dispersion, ensuring that inorganic particles are evenly distributed at the molecular level in the coating liquid, which prevents image defects while maintaining mechanical strength.
3Stability of the object's composition
If conventional dispersing agents are used to maintain particle dispersion, then dispersion stability is improved, but electrical properties deteriorate
Solution Approach 1:
The invention uses a composite dispersing agent system combining polyester resin and acrylic resin in specific proportions. This composite dispersing agent provides superior dispersion stability while having minimal negative impact on electrical properties compared to conventional single-component dispersing agents. The synergistic effect of the two resins allows for optimized performance balance.
Solution Approach 2:
The invention optimizes the composition parameters of the dispersing agent, specifically the ratio of polyester resin to acrylic resin and their respective molecular weights. By carefully controlling these parameters, the dispersing agent achieves maximum dispersion stability while minimizing interference with charge transport, thus preserving electrical properties.
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 achieves excellent dispersion stability and uniform film formation, suppressing image defects and maintaining electrical properties under varying temperature and humidity conditions, thereby improving the overall performance and productivity of electrophotographic photoreceptor production.
Implementation Method 1
subjecting the particulate silicon compound to surface treatment with a reactive organosilicon compound
Implementation Method 2
reactive organosilicon compound
Data Source
AI summary
Provided is a lamination-type electrophotographic photoreceptor comprising a conductive substrate, and a charge transport layer and a charge generation layer both on the conductive substrate, wherein the charge transport layer comprises a charge transport substance represented by the general formula (1), a binder resin, and a particulate silicon compound.