Ink Composition Dye Spectrum Width for Dark Tone Reproduction
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Solution Overview
Problem
Magenta inkjet inks used in recording processes suffer from poor dark tone reproduction, resulting in rough and non-smooth images due to the combination of anthrapyridone and azo dyes, which are effective in color strength and lightfastness but inadequate in reproducing dark tones.
Innovation Solution
An ink composition combining dyes A and B, where dye A has a narrow absorption spectrum width (≤50 nm) for high chroma and resistance, and dye B has a broader width (≥70 nm) for improved dark tone reproduction, along with a surfactant and water-soluble organic solvent to enhance printing stability and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anthrapyridone and azo dyes are combined to improve color strength and lightfastness, then color strength and resistance to gases are improved, but dark tone reproduction deteriorates
Solution Approach 1:
The patent combines three types of dyes (anthrapyridone dye, azo dye, and phthalocyanine dye) in specific proportions to create a composite ink formulation. The phthalocyanine dye is specifically added to improve dark tone reproduction while maintaining the color strength and gas resistance provided by the anthrapyridone and azo dyes. This composite approach allows the ink to achieve balanced performance across multiple parameters that were previously contradictory.
2Reliability
If dye concentration is increased to improve color strength, then color strength is improved, but image smoothness deteriorates
Solution Approach 1:
The patent optimizes the concentration ratios of different dye components rather than simply increasing total dye concentration. Specifically, it controls the ratio of anthrapyridone dye to azo dye to be within 95:5 to 50:50 by mass, and adds phthalocyanine dye at controlled concentrations. This parameter optimization ensures sufficient color strength while maintaining image smoothness by preventing excessive dye aggregation.
3Duration of action of stationary object
If ink formulation is optimized for lightfastness using anthrapyridone dye, then lightfastness is improved, but dark tone reproduction deteriorates
Solution Approach 1:
The patent creates a composite dye system where anthrapyridone dye provides lightfastness, azo dye provides color strength, and phthalocyanine dye specifically addresses dark tone reproduction. The synergistic combination allows the ink to maintain excellent lightfastness from the anthrapyridone component while the phthalocyanine component ensures proper dark tone reproduction, resolving the contradiction between these two properties.
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 composition produces images with improved color strength, dark tone reproduction, and resistance to gases, maintaining stability during prolonged printing processes, especially when using continuous-supply ink containers.
Implementation Method 1
dye A, having the width at half height of the largest peak in the absorption spectrum between 380 nm and 780 nm is 50 nm or less
Implementation Method 2
dye B, having the width at half height of the largest peak in the absorption spectrum between 380 nm and 780 nm is 70 nm or more
Data Source
AI summary
An ink composition contains dyes A and B. Dye A has a width at a half height of the largest peak in the absorption spectrum between 380 nm and 780 nm that is 50 nm or less. Dye B has a corresponding width at the half height that is 70 nm or more. Dye A is present in an amount of 40% by mass or more and 90% by mass or less of the total mass of the dyes.