Water-Based Ink Composition for Stability and Image Density
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Solution Overview
Problem
Existing inks struggle to balance preservation stability and image density, often requiring multiple compounds that increase production costs and may compromise solvent compatibility.
Innovation Solution
A water-based ink formulation using a specific surfactant with a butylene oxide chain and ethylene oxide chains, combined with a water-soluble solvent of specific hydrophobicity, to achieve both high preservation stability and image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pigments are highly dispersed in the solvent using multiple compounds, then preservation stability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent combines the functions of multiple compounds (dispersant and affinity enhancer) into a single surfactant molecule with specific structure (general formula (1)). This surfactant simultaneously provides pigment dispersion in the solvent and enhances affinity with cellulose fibers, thereby improving preservation stability while reducing the number of compounds from two to one.
Solution Approach 2:
The surfactant of general formula (1) performs multiple functions: it acts as a dispersant to maintain pigment stability in the solvent, and simultaneously enhances the affinity between pigment and cellulose fiber. This multi-functionality eliminates the need for separate compounds, reducing production complexity while maintaining high preservation stability.
2Reliability
If pigments are highly dispersed in the solvent, then preservation stability is improved, but image density deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the surfactant to achieve optimal balance. By specifying that x is 4-10 and y is 1-5 in general formula (1), the surfactant provides sufficient hydrophilic character for good dispersion (preservation stability) while maintaining adequate hydrophobic character through the butylene oxide chain for strong pigment-fiber affinity (image density).
Solution Approach 2:
The surfactant represents a composite molecular structure combining ethylene oxide chains (for water solubility and dispersion) and butylene oxide chains (for hydrophobic interaction with pigment and fiber). This composite structure enables simultaneous achievement of preservation stability and image density by balancing opposing requirements.
3Reliability
If multiple compounds are used to improve preservation stability and image density, then both properties are enhanced, but production cost increases
Solution Approach 1:
The patent merges the functions of two separate compounds (dispersant and affinity enhancer) into a single surfactant of general formula (1). This reduces the number of raw materials that need to be procured, stored, and processed, thereby lowering production costs while maintaining both preservation stability and image density enhancement.
Solution Approach 2:
The patent extracts and eliminates the need for the second compound (affinity enhancer) by incorporating its function directly into the surfactant structure. The butylene oxide chain in the surfactant provides the necessary hydrophobic interaction with cellulose fibers, making a separate affinity enhancer unnecessary and thus reducing production costs.
4Reliability
If strong pigment-solvent interaction is used to improve preservation stability, then image density deteriorates
Solution Approach 1:
The surfactant exhibits local quality differentiation: the ethylene oxide chains (hydrophilic portion) interact with the solvent to provide stability, while the butylene oxide chain (hydrophobic portion) interacts with the pigment and cellulose fiber to enhance image density. This spatial separation of functions within the single molecule resolves the contradiction between strong solvent interaction and strong fiber interaction.
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 both high preservation stability and image density, with clear and durable images on various recording media, while reducing the number of required raw materials and maintaining ejection stability.
Implementation Method 1
a surfactant represented by the following general formula (1)
Implementation Method 2
a water-soluble solvent having a log Kow of −1.0 or more and 0.85 or less
Data Source
AI summary
An ink includes: a surfactant having a main skeleton represented by the following general formula (1), a water-soluble solvent having a log Kow of −1.0 or more and 0.85 or less, a pigment, and water. A content of the water-soluble solvent is 20 mass % or more and 50 mass % or less.In the general formula (1), x represents an integer of 4 or more and 10 or less, and y represents an integer of 1 or more and 5 or less.