Non-aqueous Ink Composition for Ejection Stability
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Solution Overview
Problem
Non-aqueous ink compositions for ink jet recording face issues with agglomeration variation, abrasion resistance, and glossiness due to solvent combinations affecting drying speed and fixability, leading to instability in image quality and ejection stability.
Innovation Solution
A non-aqueous ink composition containing a colorant, lactone, a first solvent with high water vapor pressure, and a second solvent selected from (poly)alkylene glycol monoalkyl ether and (poly)alkylene glycol dialkyl ether, optimized in specific mass ranges to improve abrasion resistance, suppress agglomeration, and maintain ejection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solvent having an effect that improves the fixability of the ink is selected, then the fixability of ink is improved, but the glossiness of recorded images degrades
Solution Approach 1:
The patent applies parameter changes by carefully controlling the water vapor pressure parameters of the solvents used. Specifically, it employs a first solvent with water vapor pressure of 2 hPa or more and a second solvent with water vapor pressure of 0.9 hPa or more, maintaining specific content ratios (first solvent: 5-18% by mass, second solvent: 2-80% by mass). This parameter optimization allows achieving both good fixability and glossiness by balancing the evaporative rates and surface tension characteristics of the solvent mixture.
Solution Approach 2:
The patent uses a composite solvent system combining a first solvent (ester-based, ketone-based, alcohol-based, or amide-based) and a second solvent ((poly)alkylene glycol monoalkyl ether or (poly)alkylene glycol dialkyl ether). This composite approach leverages the complementary properties of different solvent types to simultaneously achieve fixability enhancement and glossiness maintenance, where the first solvent provides fixability and the second solvent contributes to surface properties and gloss.
2Stability of the object's composition
If a solvent that can suppress the occurrence of the agglomeration variation of the ink is selected, then the agglomeration variation is suppressed, but the ejection stability of a recording head during recording degrades
Solution Approach 1:
The patent optimizes the water vapor pressure parameters and content ratios of the solvents to balance agglomeration suppression and ejection stability. By selecting solvents with specific water vapor pressures (first solvent: ≥2 hPa, second solvent: ≥0.9 hPa) and controlling their concentrations (first solvent: 5-18%, second solvent: 2-80%), the formulation achieves both suppressed agglomeration variation and maintained ejection stability through controlled evaporation rates and viscosity characteristics.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different solvents within the mixture. The first solvent (with higher water vapor pressure) primarily contributes to preventing agglomeration and ensuring proper flow, while the second solvent (with lower water vapor pressure) primarily contributes to maintaining ejection stability and controlling drying. This functional differentiation allows each component to optimize its specific contribution without compromising the other.
3Reliability
If the drying speed of ink is low, then the ink can be properly fixed, but the components (particularly colorants) can agglomerate and agglomeration variation occurs in images
Solution Approach 1:
The patent resolves this contradiction by optimizing the water vapor pressure and concentration parameters of the solvent mixture. The first solvent with water vapor pressure of 2 hPa or more and the second solvent with water vapor pressure of 0.9 hPa or more work together in specific ratios to create a balanced drying profile that prevents both premature drying (causing agglomeration) and excessive drying (compromising fixability).
Solution Approach 2:
The patent uses the solvent mixture as an intermediary medium that mediates between the conflicting requirements of slow drying for fixability and fast enough drying to prevent agglomeration. The specific combination of first and second solvents creates an intermediary drying rate that is slow enough to allow proper ink fixation but fast enough to prevent colorant agglomeration, effectively mediating between these opposing requirements.
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 composition achieves excellent ejection stability, suppresses agglomeration variation, and maintains image glossiness, even in high-humidity environments, with improved drying properties and abrasion resistance.
Implementation Method 1
a first solvent having a water vapor pressure of 2 hPa or more... the drying speed or fixability of ink attached to a recording medium significantly degraded. When the drying speed of ink is low... components (particularly, colorants such as pigments) contained in the ink can agglomerate
Implementation Method 2
a second solvent having a water vapor pressure of 0.9 hPa or more... there is a case in which the ejection stability of a recording head during recording degrades
Data Source
AI summary
A colorant, lactone having a content in a range of 5% by mass to 40% by mass, a first solvent having a water vapor pressure of 2 hPa or more and a content in a range of 5% by mass to 18% by mass at 20° C., and a second solvent having a water vapor pressure of 0.9 hPa or more and a content in a range of 2% by mass to 80% by mass at 20° C. are contained, a sum of the content of the first solvent and the content of the second solvent is 20% by mass or more, and the second solvent is at least one solvent selected from a group consisting of (poly)alkylene glycol monoalkyl ether and (poly)alkylene glycol dialkyl ether.