Inkjet Recording Ink Set Surface Tension Control
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Solution Overview
Problem
Current inkjet recording inks face challenges with water resistance, weather resistance, and color bleed, especially on poorly water-absorbable coated papers, which affect image quality and paper integrity.
Innovation Solution
A recording ink set comprising black, cyan, and magenta inks with water-insoluble color materials, water-soluble organic solvents, and surfactants, where the surface tension of solvents in non-black inks is higher than in black ink, and the ink set has controlled viscosity and contact angles to prevent color bleed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pigment inks are used to improve water resistance and weather resistance, then image durability is improved, but color bleed on regular paper increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the surface tension of the ink within 20-40 mN/m and viscosity within 6-20 mPa·s at 25°C. These parameter optimizations allow the pigment ink to achieve both water resistance and reduced color bleed on regular paper by balancing the ink's interaction with the paper fibers.
Solution Approach 2:
The patent uses different surfactant combinations and ratios tailored to specific paper types. The ink formulation adjusts its local properties (surface tension, wetting characteristics) to match the absorption characteristics of either regular paper or coated paper, thereby preventing color bleed while maintaining water resistance.
2Reliability
If water-insoluble color materials are used to improve water resistance, then image water resistance is improved, but color bleed on poorly water-absorbable coated paper increases
Solution Approach 1:
The patent optimizes surface tension parameters to 20-40 mN/m and viscosity to 6-20 mPa·s, which enables the ink to properly penetrate and bond with poorly water-absorbable coated papers. This parameter control prevents the ink from pooling on the surface and causing color bleed while maintaining water resistance.
Solution Approach 2:
The patent employs surfactants as intermediary substances that facilitate proper ink-paper interaction on coated surfaces. The surfactant system acts as a mediator between the water-insoluble pigment and the hydrophobic coated paper surface, enabling controlled absorption and preventing color bleed.
3Object-affected harmful factors
If large difference in physical properties between inks is used to control color bleed, then color bleed is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent maintains homogeneity across all ink colors by keeping viscosity differences within 0.7-4.0 mPa·s and surface tension within 20-40 mN/m. This homogeneous formulation approach eliminates the need for complex nozzle selection and device design while still preventing color bleed through optimized physical properties.
Solution Approach 2:
The patent creates a universal ink formulation that works across all color channels (black, cyan, magenta, yellow) with consistent physical properties. This multi-functional ink design prevents color bleed without requiring different nozzle configurations or complex printing system adjustments.
4Ease of operation
If high water content ink is used to improve ease of operation, then ink flow is improved, but paper cockling increases
Solution Approach 1:
The patent optimizes the water content parameter to balance ink flow properties with paper integrity. By controlling water content alongside surface tension (20-40 mN/m) and viscosity (6-20 mPa·s), the ink maintains stable discharge and good flow characteristics while minimizing excessive water absorption that causes paper cockling.
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 achieves excellent image formation with improved water and weather resistance, reducing color bleed on regular and poorly water-absorbable papers, ensuring high-quality prints without paper deformation.
Implementation Method 1
the surface tension of the water-soluble organic solvent(s) used only for the inks other than the black ink is higher than that of the water-soluble organic solvent used only for the black ink
Implementation Method 2
the initial wet property of ink relative to recording media affects color bleed
Implementation Method 3
a surfactant
Implementation Method 4
the difference in dynamic contact angle, and the rate of dot-dimension change
Data Source
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AI summary
The present invention provides a recording ink set containing a black ink, a cyan ink, a magenta ink, and a yellow ink, each of which contains water, a water-insoluble color material, a water-soluble organic solvent, and a surfactant, wherein the black ink and at least one of the inks other than the black ink respectively contain a different water-soluble organic solvent; and the surface tension of the water-soluble organic solvent(s) used only for the inks other than the black ink is higher than that of the water-soluble organic solvent used only for the black ink; and the present invention also provides a recording method using the recording ink set.