Ink Set Surface Tension Control for Inkjet Image Quality
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Solution Overview
Problem
The existing inkjet recording methods face challenges in achieving high image quality due to issues like bleeding, beading, and mottling, which are exacerbated by inappropriate control of the static and dynamic surface tensions of the treatment liquid and ink.
Innovation Solution
The solution involves formulating an ink set with specific components, including a pigment, resin fine particles, a water-soluble solvent, and a surfactant, and a treatment liquid containing a polyvalent metal salt, a water-soluble solvent, and a surfactant. By controlling the static and dynamic surface tensions within specific ranges, the ink set ensures proper aggregation and diffusion, thereby suppressing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the treatment liquid and ink are applied with appropriate surface tension control, then image quality is improved, but the complexity of the process increases due to precise parameter control requirements
Solution Approach 1:
The patent applies parameter changes by precisely controlling the static surface tension (γs) and dynamic surface tension (γd) of both the treatment liquid and ink within specific numerical ranges. The treatment liquid is designed with γs of 20-30 mN/m and γd of 15-25 mN/m, while the ink has γs of 25-35 mN/m and γd of 30-40 mN/m. This quantitative parameter control resolves the contradiction by providing clear, measurable targets that improve image quality while maintaining manageable process complexity through defined specifications.
2Reliability
If the ink aggregation is increased to prevent bleeding, then adhesion is improved, but the glossiness of the image deteriorates due to excessive aggregation
Solution Approach 1:
The patent resolves this contradiction by controlling the surface tension parameters within specific ranges that balance aggregation and glossiness. The treatment liquid's dynamic surface tension (15-25 mN/m) is lower than its static surface tension (20-30 mN/m), creating optimal conditions for controlled aggregation that prevents bleeding while maintaining image glossiness. This quantitative control ensures sufficient adhesion without excessive aggregation.
Solution Approach 2:
The patent applies the dynamics principle by utilizing the difference between static and dynamic surface tension of the treatment liquid. The dynamic surface tension (γd) is designed to be lower than the static surface tension (γs), creating a time-dependent surface property that facilitates controlled ink aggregation during the printing process. This dynamic characteristic allows the system to adapt during application, preventing bleeding while preserving image quality and glossiness.
3Reliability
If the treatment liquid is applied in advance to improve adhesion, then base material adhesion is enhanced, but image defects such as bleeding and beading occur if surface tension is not appropriately controlled
Solution Approach 1:
The patent resolves this contradiction by establishing specific surface tension parameter ranges for the treatment liquid. The static surface tension is controlled at 20-30 mN/m and dynamic surface tension at 15-25 mN/m, with the dynamic tension being lower than the static tension. These quantitative specifications ensure that the treatment liquid provides excellent base material adhesion while preventing image defects such as bleeding and beading when used with compatible inks.
Solution Approach 2:
The treatment liquid acts as an intermediary between the base material and the ink, with its surface tension properties carefully tuned to facilitate proper interaction. By controlling the treatment liquid's static and dynamic surface tensions within specific ranges, it serves as a mediator that enhances adhesion to the base material while preventing harmful interactions with the ink, thereby avoiding image defects.
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
This approach results in high image quality with improved adhesion to the base material, enhanced injection stability, and storage stability, while effectively preventing bleeding and maintaining the clarity of outlined characters and thin lines.
Implementation Method 1
the ink contains a pigment, resin fine particles, a water-soluble solvent having a boiling point within the range of 150 to 250°C, and a surfactant, the treatment liquid contains a polyvalent metal salt, a water-soluble solvent having a boiling point within the range of 150 to 250°C, and a surfactant
Implementation Method 2
a treatment liquid (also referred to as a 'pretreatment liquid' or a 'primer') containing a flocculant such as an organic acid or a polyvalent metal salt is applied to a base material in advance, whereby pigments contained in the ink are aggregated to pinning by an organic acid or a polyvalent metal salt
Implementation Method 3
a dynamic surface tension in a surface life of 15ms of the ink is in the range of 35 to 45mN/m, and a dynamic surface tension in the surface life of 15ms of the treatment liquid is in the range of 25 to 35mN/m
Data Source
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AI summary
The ink set of the present invention is an ink set including an ink and a treatment liquid, wherein the ink contains a pigment, resin fine particles, a water-soluble solvent having a boiling point within a range of 150 to 250°C, and a surfactant, the treatment liquid contains a polyvalent metal salt, a water-soluble solvent having a boiling point within a range of 50 to 250°C, and a surfactant, a static surface tension of the ink at 25°C is 5mN/m or higher than that of the treatment liquid at 25°C, a dynamic surface tension in a surface life of 15ms of the ink at 25°C is 5mN/m or higher than that of the treatment liquid in a surface life of 15ms at 25°C, a dynamic surface tension in the surface life of 15ms of the ink is in the range of 35 to 45mN/m, and a dynamic surface tension in the surface life of 15ms of the treatment liquid is in the range of 25 to 35mN/m.