Black Ink Formulation for Neutral Tone and Light Fastness
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Solution Overview
Problem
Ink jet recording methods face challenges in maintaining image stability, particularly with black ink, as it tends to exhibit poor light fastness and color tone changes when exposed to light, humidity, or environmental gases, and existing solutions often compromise ink reliability or ejection performance.
Innovation Solution
A black ink formulation comprising a combination of three specific coloring materials, represented by general formulas (I), (II), and (III), which optimize the distribution and interaction of these materials within the ink-receiving layer to achieve a neutral color tone and balanced light fastness, using aromatic or heterocyclic groups and solubilizing agents to control permeation depth and aggregation, thereby stabilizing the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additives such as ultraviolet absorbent and antioxidant are increased in content to inhibit deterioration of coloring material, then light fastness is improved, but ink reliability deteriorates causing ejection failure or sticking
Solution Approach 1:
The patent changes the chemical structure parameters of the coloring material itself rather than adding additives. By designing specific molecular structures ( formulas (I), (II), and (III) with defined aromatic groups,azo bonds, and solubilizing groups), the coloring material inherently resists light-induced deterioration without requiring high concentrations of additives that would compromise ejection performance.
Solution Approach 2:
The patent combines three different coloring materials with complementary structures into a composite ink formulation. This composite approach allows each component to contribute different properties: one provides high optical density, another ensures neutral color tone, and the third enhances light fastness, achieving both reliability and operational performance through synergistic combination.
2Manufacturing precision
If a single azo dye is used to achieve high optical density, then image density is improved, but color tone neutrality deteriorates
Solution Approach 1:
The patent merges three distinct coloring materials into a single ink formulation, where each material is optimized for a specific function. One compound provides high optical density through its extended conjugated system, another ensures neutral color tone by balancing absorption across the visible spectrum, and the third enhances stability. The combination achieves both high density and color neutrality that cannot be obtained with a single dye.
3Manufacturing precision
If multiple different dyes are combined to achieve neutral color tone and high optical density, then image quality is improved, but ink composition complexity increases
Solution Approach 1:
The patent assigns specific functional qualities to each of the three coloring material positions in the formulation. Rather than using three dyes with overlapping similar functions, each compound is designed with localized specialization: one optimized for maximum optical density through specific aromatic group arrangements, another for neutral color balance through controlled absorption characteristics, and a third for enhanced stability. This functional differentiation reduces the need for complex ratios and simplifies formulation while maintaining high image quality.
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 provides an image with an initial neutral color tone that remains stable after light fastness testing, maintaining a balanced color tone and optical density across wavelength regions, ensuring excellent light fastness and reduced color change, even in gradation properties.
Implementation Method 1
optimize the distribution and interaction of these materials within the ink-receiving layer
Data Source
AI summary
Provided is a black ink which provides an image with excellent color tone, little color tone change after a light fastness test and excellent balance of color tone change and light fastness. The black ink further provides an image with a gradation property having a color tone close to a neutral color tone even before and after a light fastness test. The ink contains at least a compound represented by the general formula (I) as a first coloring material, a compound represented by the general formula (II) as a second coloring material and a compound represented by the general formula (III) as a third coloring material