Aqueous Black Ink Composition Ozone Resistance
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Solution Overview
Problem
Current inkjet recording methods face challenges in achieving stable, neutral black to gray colors with high print density and excellent ozone-gas resistance, particularly in ink compositions used for inkjet recording, where ozone gas causes discoloration and fading of recorded images.
Innovation Solution
An aqueous black ink composition is developed containing specific coloring matters represented by formulas (I), (II), and (III), which include tautomers and salts, providing a blend that ensures stability, neutral coloration, and enhanced fastness properties such as ozone-gas resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional aqueous inks with water-soluble dyes are used, then ease of manufacture and solubility are improved, but gas resistance deteriorates due to discoloration and fading from ozone gas oxidation
Solution Approach 1:
The patent employs composite coloring matter systems combining multiple dye types (azo dyes, anthraquinone dyes, indigo dyes, and phthalocyanine dyes) with specific chemical structures and properties. This composite approach creates synergistic effects where the combination provides superior ozone resistance compared to individual dyes, while maintaining good solubility and ease of manufacture. The composite material strategy allows selection of dyes with complementary properties to achieve both manufacturing ease and environmental stability.
Solution Approach 2:
The patent systematically optimizes multiple parameters including dye concentration ratios, molecular weight ranges, solubility characteristics, and chemical structure parameters of the coloring matters. By adjusting these parameters within specific ranges and combinations, the ink formulation achieves enhanced ozone resistance while maintaining adequate solubility and manufacturability. The parameter optimization includes controlling the ratio of different dye types and their respective concentrations to balance performance and ease of manufacture.
2Shape
If multiple coloring matters are mixed to achieve neutral black color, then color neutrality is improved, but discoloration from decomposition increases
Solution Approach 1:
The patent assigns specific functional roles to different coloring matter components based on their local chemical properties and stability characteristics. Each dye type is selected for its specific contribution to color neutrality and its resistance to particular degradation mechanisms. This localized functional assignment allows the mixture to achieve overall neutrality while individual components resist decomposition, reducing total discoloration.
Solution Approach 2:
The patent transforms the potential harm of using multiple dyes (which could lead to decomposition and discoloration) into a benefit by carefully selecting dye combinations where the interactions stabilize the system. The mixture creates a synergistic effect where the presence of multiple dye types actually enhances overall stability and reduces individual decomposition rates, converting the risk of mixing into a protective mechanism against discoloration.
Data Source
AI summary
An aqueous black ink composition that produces a black recorded image that is stable even when stored for a long time period, exhibits a neutral black to gray color with low color saturation and no tinge, has a high printed image density and exhibits excellent fastness properties of the recorded image, particularly ozone-gas resistance. The ink composition contain at least one kind of coloring matter (I), which a coloring matter represented by formula (1) below, a tautomer thereof, or a salt of the coloring matter or the tautomer; at least one kind of coloring matter (II), which is a coloring matter represented by formula (2) below or a salt thereof; and coloring matter (III), which is a coloring matter having an azo group other than coloring matters (I) and (II), or a salt thereof.