Aqueous Inkjet Printing With Moisture-Controlled UV Curing
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Solution Overview
Problem
Existing ink jet printing methods using UV-curable inks face issues with non-uniform printed surfaces, curling of printed products, and bleeding between colors, especially with aqueous UV-curable inks, which also struggle to form porous structures.
Innovation Solution
An ink jet printing method utilizing an aqueous ink containing a water-soluble polymerizable component that undergoes polymerization solid-liquid separation, allowing for moisture removal and preventing curling, with controlled moisture concentrations to facilitate the formation of a porous structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV-curable ink is used to achieve high fastness immediately after printing, then the ink components are cured and form a cured product, but the surface heights of the image differ depending on application amount making it difficult to uniformize the printed surface
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by introducing a specific polymerizable compound with hydroxyl groups and controlling its molecular weight and functional group content. This allows the ink to maintain uniform surface heights while achieving high fastness through UV curing, resolving the contradiction between reliability and manufacturing precision.
2Manufacturing precision
If aqueous UV-curable ink is used to uniformize the printed surface and improve safety, then water is used as diluent reducing surface height differences, but the cured product holds moisture causing curling particularly when application amount is large
Solution Approach 1:
The patent modifies the chemical parameters of the polymerizable compound by specifying molecular weight ranges (500-2000) and functional group content (2-10 per molecule), which controls the curing characteristics to minimize moisture retention and prevent curling while maintaining surface uniformity.
Solution Approach 2:
The patent creates a composite ink formulation combining water with specific polymerizable compounds containing hydroxyl groups, which provides both the surface uniformity benefits of aqueous systems and reduced moisture retention through the specific chemical structure of the polymerizable compound.
3Ease of operation
If low-viscosity UV monomer is incorporated to reduce ink viscosity for ejection, then the ink can be ejected from printing head, but the monomer is volatile and emits odor causing environmental concerns
Solution Approach 1:
The patent changes the molecular weight parameter of the polymerizable compound to a specific range (500-2000) that provides adequate viscosity for ejection while reducing volatility and odor compared to lower molecular weight monomers, thus resolving the contradiction between ease of operation and harmful factors.
4Loss of substance
If image is dried before UV irradiation to remove water, then moisture removal is achieved, but the ink cannot be pinned immediately after application allowing bleeding between colors
Solution Approach 1:
The patent applies UV irradiation as a preliminary action immediately after ink application to pin the image before moisture removal, preventing bleeding between colors. The specific polymerizable compound formulation enables effective pinning even in the presence of water, resolving the contradiction between moisture removal and color separation.
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 uniform printed surfaces, prevents curling and bleeding, and allows for on-demand production of porous bodies with desired shapes, enhancing printing quality and versatility.
Implementation Method 1
an ink containing a water-soluble polymerizable component A and water is ejected from a printing head of an ink jet system to apply the ink to a medium M, to thereby form a first image... applying an active energy ray to the first image to form a second image... the polymerizable component A is dissolved in the first image
Implementation Method 2
utilizing an aqueous ink containing a water-soluble polymerizable component that undergoes polymerization solid-liquid separation, allowing for moisture removal and preventing curling, with controlled moisture concentrations to facilitate the formation of a porous structure
Data Source
AI summary
Provided is an ink jet printing method including: a first step of ejecting an ink containing a water-soluble polymerizable component A and water from a printing head of an ink jet system to apply the ink to a medium M, to thereby form a first image; and a second step of applying an active energy ray to the first image to form a second image. The polymerizable component A is dissolved in the first image, and a moisture concentration “x” (mass %) in the first image and a moisture concentration “y” (mass %) in the second image placed under an environment at a humidity of 95% satisfy a relationship of 0<(y/x)≤0.80.