Ink Composition for Ozone Resistance and Color Stability
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Solution Overview
Problem
Ink jet recording methods face challenges with image ozone resistance, color tone stability, and sticking resistance due to the use of water-soluble organic solvents, leading to color tone changes and reduced image quality.
Innovation Solution
An ink composition is developed with a first black coloring material that exhibits a significant difference in maximum absorption wavelength between low and high polarity environments, combined with a second coloring material that minimizes this shift, ensuring uniform color tone and improved ozone resistance, while maintaining sufficient sticking resistance by controlling the total content of these materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coloring material with an easily associating molecular structure is used to improve ozone resistance, then ozone resistance is improved, but color tone change occurs due to association state changes
Solution Approach 1:
The patent uses a composite coloring material system comprising multiple dyes (e.g., cyan, magenta, yellow dyes in specific combinations) to achieve both ozone resistance and color tone stability. The composite system balances the association behavior of individual dyes, preventing color tone changes while maintaining high ozone resistance through synergistic interactions among the dye components.
Solution Approach 2:
The patent optimizes specific parameters including the concentration ratios of different dyes, the presence of co-solvents with controlled dielectric constants, and pH adjustments to control the association state of the coloring materials. By carefully adjusting these parameters, the system achieves stable color tone while maintaining the easily associating structure necessary for ozone resistance.
2Ease of operation
If water-soluble organic solvents are used in ink composition, then ink jet recording performance is improved, but color tone change occurs due to influence on easily associating coloring material
Solution Approach 1:
The patent introduces co-solvents with specific dielectric constants as intermediary substances that mediate between the water-soluble organic solvents and the easily associating coloring materials. These intermediary substances buffer the effect of water-soluble solvents on dye association, maintaining color tone stability while preserving the benefits of water-soluble formulations for ink jet recording.
Solution Approach 2:
The patent carefully selects and controls the dielectric constant of co-solvents and the overall polarity of the ink formulation. By adjusting these physical parameters, the system maintains optimal balance between ink jet recording performance (requiring water-solubility) and color tone stability (requiring controlled association).
3Quantity of substance
If coloring material concentration is increased to improve image density, then image density is improved, but sticking resistance decreases due to cohering of coloring material
Solution Approach 1:
The patent optimizes the concentration of coloring materials within specific ranges and adjusts related parameters such as pH, ionic strength, and presence of complexing agents. These parameter adjustments prevent excessive cohering of coloring material molecules even at higher concentrations, thereby achieving high image density while maintaining adequate sticking resistance.
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 achieves enhanced ozone resistance, suppressed color tone changes, and improved sticking resistance, even in environments with varying water-soluble organic solvents, ensuring consistent image quality and reduced bronzing phenomena.
Implementation Method 1
a first black coloring material (1) exhibiting a difference Δλmax1 (=λmaxD1-λmaxW1) of 20.0 or more between a maximum absorption wavelength (λmaxD1) in a 20.0% by mass aqueous solution of 1,2-hexanediol and a maximum absorption wavelength (λmaxW1) in water
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An ink containing a first coloring material and a second coloring material, the sum total of these contents being 6.0% by mass or less. The first coloring material is a black coloring material exhibiting a difference Δλmax1 of 20.0 or more between a maximum absorption wavelength in a 20.0% by mass aqueous solution of 1,2-hexanediol and a maximum absorption wavelength in water, the second coloring material is a specific coloring material exhibiting a difference Δλmax2 of 12.0 or less between a maximum absorption wavelength in a 20.0% by mass aqueous solution of 1,2-hexanediol and a maximum absorption wavelength in water, and the sum of the Δλmax1 and the Δλmax2 is 35.0 or less.