Piezoelectric Ejection Nozzles for Uniform Photoreceptor Coating
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Solution Overview
Problem
Conventional methods for forming electrophotographic photoreceptors, such as dip coating, roll coating, blade coating, and spraying, face issues with non-uniform film thickness, clogging of ejection nozzles due to dryness and aggregation, and poor production efficiency, especially when using organic photoconductive materials like phthalocyanine compounds.
Innovation Solution
A coating composition with a viscosity of 1 mPa·s to 10 mPa·s, containing high-boiling point solvents (120° C. to 260° C.) and a specific ratio of high-boiling to low-boiling point solvents, is ejected from nozzles as droplets to form a uniform charge-generating layer, preventing nozzle clogging and ensuring stable ejection and uniform film thickness, using a piezoelectric ejection mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating methods (dip coating, roll coating, blade coating, spray coating) are used to form photosensitive layers, then coating can be applied to conductive substrates, but the film thickness is non-uniform and production efficiency is poor
Solution Approach 1:
The patent segments the coating composition into discrete droplets that are ejected from multiple nozzles arranged in arrays. Each nozzle deposits controlled amounts of material, and the segmented droplet pattern coalesces to form a uniform continuous film. This segmentation approach enables precise control over film thickness while maintaining high production efficiency through parallel deposition from multiple nozzles.
2Loss of substance
If coating composition is stored and reused, then cost efficiency improves, but the solvent evaporates causing the composition to dry and clog ejection nozzles
Solution Approach 1:
The patent changes the physical parameter of the solvent by selecting one with a high boiling point (120°C to 260°C). This parameter change reduces the solvent's evaporation rate, allowing the coating composition to be stored and reused without significant solvent loss. The high boiling point solvent maintains the composition's fluidity and prevents nozzle clogging during storage and repeated use, while still enabling adequate drying after application.
3Ease of operation
If the coating composition viscosity is reduced for easy ejection, then ejection stability improves, but the composition becomes difficult to handle and may aggregate
Solution Approach 1:
The patent optimizes the viscosity parameter of the coating composition to fall within the range of 1 mPa·s to 10 mPa·s. This parameter change achieves a balance between ejection stability and composition homogeneity. The viscosity is low enough to allow smooth ejection from nozzles without clogging, yet high enough to prevent premature aggregation of the photoconductive particles and maintain uniform distribution of components throughout the composition.
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 enables stable ejection and uniform application of the coating composition, preventing nozzle clogging and achieving a uniform charge-generating layer with improved leveling performance, leading to enhanced image quality and production efficiency.
Implementation Method 1
using a piezoelectric ejection mechanism
Implementation Method 2
the solvent contains one or at least two high-boiling point solvents having a boiling point of 120° C. to 260° C.
Data Source
AI summary
A coating composition for an electrophotographic photoreceptor that forms a charge-generating layer by being ejected from ejection nozzles in a form of droplets, comprises a charge-generating substance, a binding resin, and a solvent, has a viscosity of 1 mPa·s to 10 mPa·s, and the solvent contains at least one kind of high-boiling point solvent having a boiling point of 120° C. to 260° C., and the high-boiling point solvent is contained at a ratio of 5 parts by weight to 40 parts by weight with respect to 100 parts by weight of the coating composition for an electrophotographic photoreceptor.