Water-Based Ink Set Gloss Uniformity via Particle Diameter Control
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving uniform gloss across images printed with multiple color inks, leading to perceived flaws due to differences in gloss levels when viewed from various angles.
Innovation Solution
A water-based ink set comprising two or more inks with different pigments and resin particles, mixed with a 5% by mass water-based solution of magnesium sulfate heptahydrate to achieve a volume average particle diameter difference of 40% or less, along with a treatment liquid containing an aggregating agent, to enhance aggregation and reduce gloss differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple color inks are used for recording, then color variety and image content are improved, but gloss uniformity deteriorates causing perceived flaws
Solution Approach 1:
The patent applies local quality by adjusting the particle diameter of resin components specifically in inks that tend to produce high gloss (such as yellow and cyan inks). By making the resin particles in these inks smaller (0.01-0.1 μm) compared to other inks (0.03-0.2 μm), the patent creates localized modifications in particle characteristics to balance the gloss across different color regions, thereby resolving the gloss uniformity issue while maintaining color variety
Solution Approach 2:
The patent employs parameter changes by systematically varying the particle diameter parameter of resin components across different ink formulations. The resin particle diameters are precisely controlled within specific ranges (0.01-0.2 μm) and adjusted according to the ink color type. This parameter optimization ensures that the volume average particle diameters of all inks fall within 40% of each other, achieving gloss uniformity across multiple colors
2Strength
If resin particles are aggregated to improve adhesion, then ink adhesion is improved, but particle diameter increases causing gloss differences
Solution Approach 1:
The patent resolves this contradiction by optimizing the particle diameter parameter of resin components to a specific range (0.01-0.2 μm) that balances adhesion and gloss uniformity. By controlling resin content (0.1-20% by mass) and particle size, the patent achieves effective aggregation for adhesion while preventing excessive particle growth that would cause gloss differences. The volume average particle diameter of all inks is maintained within 40% of each other
Solution Approach 2:
The patent applies local quality by differentiating resin particle characteristics based on ink type. Yellow and cyan inks use smaller resin particles (0.01-0.1 μm) to control gloss, while other inks use slightly larger particles (0.03-0.2 μm). This localized differentiation allows each ink to achieve optimal adhesion while maintaining overall gloss uniformity across the color set
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 effectively reduces gloss differences between colors, resulting in images with fewer perceived flaws and improved image quality by ensuring uniform particle aggregation and better ink adhesion on the recording medium.
Implementation Method 1
the first ink and the second ink are mixed with a 5% by mass water-based solution of magnesium sulfate heptahydrate to increase a volume average particle diameter of the inks
Implementation Method 2
a treatment liquid including an aggregating agent for aggregating the components of the water-based ink compositions
Data Source
AI summary
An ink set includes a first ink and a second ink which are water-based ink compositions, in which each of the first ink and the second ink includes a pigment and resin including resin particles, the first ink includes a first pigment and the second ink includes a second pigment different from the first pigment, the first ink and the second ink are mixed with a 5% by mass water-based solution of magnesium sulfate heptahydrate to increase a volume average particle diameter of the ink and a difference in the volume average particle diameter for the inks in the inks after mixing is 40% or less, and the ink set is used for recording together with a treatment liquid including an aggregating agent for aggregating the components of the water-based ink compositions.