UV-Curable Ink Composition for High-Speed Printing
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Solution Overview
Problem
High-speed printing with ultraviolet curable ink-jet recording methods faces issues with insufficient curing and adhesion due to increased ink layer thickness, leading to curing wrinkles and poor image texture, especially with cationic polymerizable inks that have high light blocking effects and require precise polymerization initiator amounts.
Innovation Solution
An ink-jet recording device and method that uses a combination of cationic polymerizing compounds, such as epoxy compounds with oxetane rings, and controlled light irradiation to achieve efficient curing, with ink quantities above 5 g/m2 and polymerization initiator levels below 5 weight %, ensuring thorough curing and adhesion without wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ink quantity per one time ejection is increased to improve productivity, then the printing speed and efficiency are improved, but the ink layer thickness increases causing insufficient curing in the interior
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating specific photopolymerizable compounds with different curing characteristics and controlling the polymerization initiator content within 0.1-10% by weight. This allows the ink to maintain curability even when deposited in thicker layers that can be applied in fewer passes, thereby improving printing speed while ensuring complete curing.
2Speed
If the amount of polymerization initiator is increased to improve curing sensitivity, then the curing speed is improved, but the interior curing capability deteriorates due to increased ultraviolet ray absorption
Solution Approach 1:
The patent optimizes the polymerization initiator content to a specific range (0.1-10% by weight) and selects photopolymerizable compounds with appropriate ultraviolet absorption characteristics. This balanced composition ensures sufficient curing sensitivity for rapid curing while maintaining adequate ultraviolet ray penetration to the ink layer interior, resolving the contradiction between curing speed and interior curing capability.
3Productivity
If a large ink quantity is cured during one time ultraviolet irradiation, then the printing efficiency is improved, but insufficient curing is caused due to deterioration of interior curing capability
Solution Approach 1:
The patent creates a composite ink formulation combining multiple photopolymerizable compounds (epoxy compounds, oxetane compounds, and other polymerizable monomers or oligomers) with controlled polymerization initiator content. This composite composition enables the ink to be deposited in thicker, more productive layers while maintaining uniform curing throughout the ink layer thickness by balancing surface and interior polymerization rates.
4Quantity of substance
If the ink adhesion quantity is increased to improve image coverage, then the image quality is improved, but bleeding among multi-colors is caused
Solution Approach 1:
The patent replaces reliance on substrate absorption (mechanical/physical process) with photochemical curing as the primary ink fixation mechanism. By using photopolymerizable compounds that cure upon ultraviolet irradiation, the ink can be applied in larger quantities for better coverage without causing color bleeding, as the curing process occurs chemically rather than relying on absorption rates that vary with ink quantity.
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 high-speed printing with improved adhesion and reduced curing wrinkles, maintaining image quality by balancing curing rates between the ink surface and interior, even with thick ink layers.
Implementation Method 1
a polymerization initiator, and an ink-jet recording device, which utilizes a combination of cationic polymerizing compounds
Data Source
AI summary
An ink-jet recording device which is equipped with a recording head to eject one type or plural types of inks containing a photo-curable component onto a recording medium and a light irradiation device to cure the ink by irradiating light onto the ink having deposited on the recording medium, wherein ink quantity cured by one time light irradiation is not less than 5 g/m2, and an amount of a photo-polymerization initiator in the ink is not more than 5 weight % based on the total weight of the ink.