Inert UV Inkjet Printing with Dual Curing Modes
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Solution Overview
Problem
Ultraviolet inkjet printing faces challenges with oxygen inhibition, high energy and photoinitiator requirements for curing, increased ink costs due to thick films, and limited control over surface finish and glossiness.
Innovation Solution
Creating a reduced oxygen curing region using atmospheric-barrier films or rollers to isolate ink droplets from oxygen, allowing for lower energy UV curing and adjusting surface appearance by applying pressure and films to spread and smooth ink droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-energy UV sources and high photoinitiator concentration are used to cure ink in air environment, then complete curing is achieved, but ink costs increase and final film properties deteriorate
Solution Approach 1:
The patent applies inert atmosphere by introducing nitrogen gas into the curing chamber to displace oxygen. This creates an oxygen-free environment that eliminates oxygen inhibition, allowing complete curing with lower UV energy and photoinitiator concentration. The nitrogen atmosphere prevents oxygen from interfering with the polymerization process while maintaining a controlled environment suitable for ink curing.
2Object-affected harmful factors
If atmospheric oxygen is completely replaced with inert gas, then oxygen inhibition is eliminated, but system complexity and cost increase
Solution Approach 1:
The patent implements partial inert gas introduction rather than complete atmosphere replacement. Nitrogen gas is introduced at controlled rates to achieve sufficient oxygen displacement for effective curing without requiring a fully sealed and purged system. This partial action approach eliminates oxygen inhibition while maintaining system simplicity and reducing operational complexity.
3Illumination intensity
If thicker films of ultraviolet-curable ink are deposited, then color strength is improved, but ink costs increase
Solution Approach 1:
The inert nitrogen atmosphere enables more efficient UV curing by eliminating oxygen inhibition. This allows thinner ink films to achieve complete curing with sufficient color strength, as the polymerization process proceeds without oxygen interference. The improved curing efficiency means less ink is required to achieve the desired optical properties, reducing material costs.
4Shape
If longer time to lamp is allowed for ink droplet spreading, then dot gain increases and ink layer thickness decreases, but print head size and printer complexity increase
Solution Approach 1:
The nitrogen atmosphere creates optimal curing conditions that allow for controlled droplet spreading before UV exposure. The inert environment prevents premature curing, enabling the ink to spread and form the desired shape without oxygen interference. This allows for shorter time to lamp without compromising droplet formation quality, maintaining simple print head design.
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
Reduces the need for high-energy UV sources and photoinitiator concentration, decreases ink usage, and enables varying surface finishes from matte to glossy.
Implementation Method 1
The photons interact with photoinitiators present within the ink, creating free radicals. The created free radicals initiate and propagate polymerization (cure) of the monomers and oligomers within the ink.
Implementation Method 2
depositing a barrier over the resulting ink droplets in the curing region
Data Source
AI summary
Enhanced printing solutions are enabled by providing ultraviolet curing conditions without requiring complete evacuation of atmospheric oxygen. Increased ink coverage and adjusted surface appearance are also provided.