Ink Set Glossiness Control via Pigment Ratio and Clear Ink Integration
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Solution Overview
Problem
Existing inkjet recording methods face challenges in achieving printed matter-like glossiness and wide color reproducibility while minimizing the influence of image density, as they often require separate ejection heads for clear ink and result in excessive glossiness or variations in glossiness between dark and light inks.
Innovation Solution
An ink set comprising magenta and cyan inks with specific pigment concentration ratios and solid content ratios, along with a treatment liquid containing an aggregation accelerator, is applied to a recording medium to achieve desired glossiness and color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate ejection heads for clear ink are provided in a single-pass inkjet system, then glossiness can be made even, but device complexity and cost increase
Solution Approach 1:
The patent extracts the clear ink ejection function from a separate ejection head and integrates it into the existing pigment ink ejection head by formulating clear ink with the same components (pigment, resin, solvent) as pigment ink, but with different proportions (no added pigment, different resin-to-solvent ratio). This eliminates the need for separate ejection heads while maintaining the ability to control glossiness uniformly.
Solution Approach 2:
The patent makes the single ejection head universal by formulating both pigment ink and clear ink with identical base components (pigment, resin, solvent), allowing the same ejection head to handle both ink types. The clear ink uses the same resin and solvent as pigment ink but with adjusted ratios, enabling one head to perform multiple functions without requiring separate specialized heads.
2Manufacturing precision
If clear ink is applied to achieve even glossiness, then glossiness uniformity improves, but excessive glossiness occurs compared to conventional printed matter
Solution Approach 1:
The patent changes the chemical composition parameters of clear ink by adjusting the resin-to-solvent ratio and eliminating added pigment, while maintaining the same base components as pigment ink. This parameter adjustment allows the clear ink to provide glossiness uniformity without producing excessive glossiness, achieving a balance between uniformity and natural appearance comparable to conventional printed matter.
3Manufacturing precision
If pigment concentration ratios and solid content ratios are adjusted, then color reproducibility and glossiness are improved, but ink formulation complexity increases
Solution Approach 1:
The patent applies local quality by differentiating ink formulations based on their specific function: pigment ink contains pigment for color reproduction, while clear ink contains no added pigment but has adjusted resin-to-solvent ratios for gloss control. Each ink type has optimized local composition (pigment concentration, resin content, solvent ratio) tailored to its purpose, achieving wide color reproducibility and controlled glossiness without excessive overall formulation complexity.
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 ink set provides printed matter-like glossiness and wide color reproducibility while reducing the influence of image density, enhancing curling resistance, rubbing resistance, and jetting stability.
Implementation Method 1
a treatment liquid comprising an aggregation accelerator that coagulates components of the inks
Data Source
AI summary
The invention provides an ink set having at least: a magenta ink containing at least a pigment; and a cyan ink containing at least a pigment. A ratio of M/C, in which M is the concentration of the pigment in the magenta ink, and C is the concentration of the pigment in the cyan ink, is 1.6 or more. A ratio of S2/S1, in which S2 is the solid content of an ink that has the largest solid content among the inks included in the ink set, and S1 is the solid content of an ink that has the smallest solid content among the inks included in the ink set, is 1.2 or less. The invention further provides an image forming method having applying the inks of the ink set onto a recording medium.