Inkjet Coating Edge Precision via Single Nozzle Extraction
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Solution Overview
Problem
Conventional multi-nozzle inkjet coating apparatuses face challenges in achieving precise and uniform coatings, particularly at edges, due to variations in ink droplet weight and ejection position, and existing solutions are either complex or cost-ineffective.
Innovation Solution
An inkjet coating method and apparatus that extracts edge image data to form precise edge images by continuously ejecting ink droplets from a single nozzle while moving the substrate or head, followed by internal image formation, allowing for precise control of nozzle position and direction to achieve uniform and sharp edge coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple nozzles are used to eject ink droplets in edge parts, then coating coverage is improved, but edge precision deteriorates due to nozzle position variations
Solution Approach 1:
The patent extracts the edge coating function from the multi-nozzle system and assigns it to a single nozzle. The edge nozzle is specifically positioned and controlled to eject ink droplets only at edge locations, separating the edge coating task from the internal area coating task that is handled by other nozzles. This extraction eliminates the precision problems caused by using multiple nozzles for edge coating.
Solution Approach 2:
The patent applies local quality by giving different nozzles different functions based on their position and capability. The edge nozzle is specifically optimized for edge coating with controlled droplet ejection, while other nozzles handle internal area coating. This localized specialization allows each nozzle to perform its specific function with high precision.
2Manufacturing precision
If ink droplets are ejected to form sharp corners, then edge precision is improved, but coating uniformity deteriorates due to droplet expansion
Solution Approach 1:
The patent applies preliminary anti-action by forming a bank (raised structure) at the outer edge of the coating area before ink ejection. This bank acts as a physical barrier that prevents ink droplets from spreading beyond the desired edge location. The bank is treated with a repellant coating to actively prevent ink adhesion, counteracting the natural tendency of ink to spread and ensuring sharp edge definition.
3Productivity
If conventional multi-nozzle coating is used, then coating speed is improved, but coating precision deteriorates due to variations in droplet weight and ejection position
Solution Approach 1:
The patent implements feedback control by individually adjusting the drive voltage waveforms for each nozzle based on measured droplet characteristics. The system measures the weight and ejection position of ink droplets from each nozzle, then fine-tunes the drive voltage to compensate for variations. This feedback loop ensures that all nozzles produce ink droplets with consistent weight and position, achieving high coating precision while maintaining the productivity benefits of multi-nozzle operation.
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 method enables high-performance coating with a simple system, ensuring precise and uniform coatings over the entire area and sharp edges by controlling ink droplet placement and spreading, thereby overcoming the limitations of existing technologies.
Implementation Method 1
fine-tuning individual drive voltage waveforms impressed on the piezoelectric elements
Implementation Method 2
fine-tuning individual drive voltage waveforms impressed on the piezoelectric elements and heating elements of each nozzle
Data Source
AI summary
An inkjet coating method can achieve high-performance coating with a simple system by forming a precise and uniform coat over a coating area and precise edge parts on the periphery of the coating area. The inkjet coating method, firstly, extracts an edge image and an internal image from coating image. Next, the inkjet coating method forms the edge image including a plurality of edge image portions each extending to different directions, while forming each edge image portion by a single nozzle. And then, the inkjet coating method forms the internal image using a leveling technique.