Ink Jet Printing Method Using Segmented Water-Based Ink Set
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving high-speed printing on non-ink-absorbing or low-ink-absorbing recording media due to issues with abrasion resistance and clogging, as increasing the amount of coloring agents and resin components to improve abrasion resistance leads to instability in ink discharge and potential clogging in the ink jet head.
Innovation Solution
A printing method using a water-based ink set comprising a color ink with a water-insoluble coloring agent, resin component, and surfactant, and a resin ink with thermoplastic resin particles and wax, where the thermoplastic resin particles have a glass transition temperature of 40° C. or higher, and the wax content is between 0.5% to 6% by mass, to enhance abrasion resistance and prevent clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of coloring agent and resin component in ink is increased to improve abrasion resistance, then abrasion resistance is improved, but ink viscosity increases causing discharge instability and clogging in ink jet head
Solution Approach 1:
The ink is divided into multiple types (first ink and second ink) with different functions. The first ink contains coloring agents for image formation, while the second ink contains resin components for abrasion resistance. This segmentation allows each ink to have optimized composition without the constraints of mixing all components in a single ink formulation, resolving the contradiction between abrasion resistance and discharge stability.
Solution Approach 2:
The resin component is extracted from the traditional single ink formulation and applied separately as a second ink layer. This extraction allows the resin to be applied in controlled amounts specifically for abrasion resistance without compromising the discharge stability of the coloring ink, as the two functions are separated into distinct application steps.
2Strength
If the amount of coloring agent and resin component in ink is increased to improve abrasion resistance, then abrasion resistance is improved, but clogging in ink jet head occurs more easily
Solution Approach 1:
The ink system is segmented into two separate inks: first ink for coloring and second ink for resin coating. This segmentation prevents clogging by ensuring that the coloring ink (with potential clogging risks from pigments) and the resin ink (with higher viscosity) are handled separately in the ink jet system, allowing each to be optimized for its specific function without compounding clogging issues.
Solution Approach 2:
The coloring ink is applied first to form the image, followed by the resin ink application for abrasion resistance. This preliminary action sequence allows the coloring layer to be established before adding the protective resin layer, preventing clogging issues that would arise from mixing high-viscosity resin with coloring agents in a single ink formulation.
3Adaptability or versatility
If ink jet recording is performed on non-ink-absorbing or low-ink-absorbing recording medium, then image formation on diverse media is achieved, but dried ink is easily detached due to abrasion
Solution Approach 1:
The abrasion resistance function is extracted from the ink absorption function. By applying a separate resin ink layer specifically for abrasion resistance on top of the colored image, the patent enables image formation on non-ink-absorbing media (like plastics and metals) while providing the necessary protective coating that would otherwise require ink absorption into porous substrates.
Solution Approach 2:
The patent uses a composite ink system combining two different ink formulations: a coloring ink and a resin ink. This composite approach allows the first ink to provide color on diverse non-ink-absorbing media while the second ink provides the resin-based abrasion resistance layer, achieving both versatility and durability simultaneously.
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 achieves high-speed printing with improved abrasion resistance on non-ink-absorbing or low-ink-absorbing media without causing clogging in the ink jet head, ensuring stable ink discharge and high-quality image formation.
Implementation Method 1
thermoplastic resin particles as a resin component that are insoluble in water but compatible in the water-soluble resin solvent
Implementation Method 2
a drying step performed during the printing step and/or after the printing step
Data Source
AI summary
A printing method that uses ink jet recording with a water-based ink set to form an image on a non-ink-absorbing or low-ink-absorbing recording medium, the method includes a printing step including recording with a color ink and recording with a resin ink performed after the recording with the color ink; and a drying step performed during the printing step and/or after the printing step. In the printing method, the water-based ink set includes the color ink containing a water-insoluble coloring agent and the resin ink not containing a coloring agent. The color ink contains the water-insoluble coloring agent, a resin component, a water-soluble solvent, and a surfactant. The resin ink contains a water-soluble resin solvent, a wax, and thermoplastic resin particles as a resin component that are insoluble in water but compatible in the water-soluble resin solvent. A content of the thermoplastic resin particles in the resin ink is 4% by mass or more and 12% by mass or less, and a content of the wax in the resin ink is 0.5% by mass or more and 6% by mass or less.