Inkjet Ink Set Solvent Ratio for Bleeding Control
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Solution Overview
Problem
Inkjet recording systems face challenges in reducing bleeding between black and color inks, particularly with dye-based inks, and maintaining discharge reliability, due to issues with viscosity, permeability, and solvent ratios.
Innovation Solution
An inkjet recording ink set is developed with black and color inks containing dyes, water-soluble solvents, and water, where the viscosity ranges from 5 to 20 mPa·s and specific mass ratios of water-soluble solvent to water are maintained to prevent bleeding and ensure stable discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the permeability of color ink to paper is increased to prevent black ink from penetrating color ink regions, then color bleeding is reduced, but the black ink discharge stability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the water-soluble solvent content in black ink (0.1-5% by mass) while maintaining different solvent-to-water ratios for color inks (S/W ≥ 1) versus black ink (S/W < 1). This parameter optimization resolves the contradiction by achieving both reduced color bleeding and maintained discharge stability through balanced solvent composition.
2Object-affected harmful factors
If the viscosity of black ink is increased to suppress color ink permeability and reduce color bleeding, then color bleeding is reduced, but the black ink discharge reliability deteriorates due to upper viscosity limits
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing viscosity within the range of 5-20 mPa·s at 25°C and carefully controlling water-soluble solvent content (0.1-5% for black ink, ≥10% for color inks). This balanced parameter adjustment achieves both reduced color bleeding and maintained discharge reliability without exceeding viscosity limits.
3Object-affected harmful factors
If a water-soluble solvent is added to ink composition to adjust surfactant properties and reduce color bleeding, then color bleeding is reduced, but the ink discharge stability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling water-soluble solvent content within specific ranges (0.1-5% for black ink, 10-70% for color inks) and maintaining different S/W ratios. This optimized parameter combination resolves the contradiction by achieving reduced color bleeding while maintaining discharge stability through balanced solvent composition.
4Reliability
If the amount of water-soluble solvent in black ink is increased to match color inks (S/W ≥ 1), then discharge stability is improved, but color bleeding between black and color inks increases
Solution Approach 1:
The patent applies asymmetry by deliberately creating different water-soluble solvent compositions between black ink (S/W < 1, 0.1-5%) and color inks (S/W ≥ 1, 10-70%). This asymmetric composition strategy resolves the contradiction by allowing color inks to have high permeability (reducing color bleeding) while maintaining black ink discharge stability through controlled, lower solvent content.
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 set effectively reduces bleeding between black and color inks and improves discharge reliability, enhancing the quality of printed images by maintaining optimal viscosity and solvent balance.
Implementation Method 1
using an ink flying unit configured to make the respective inks fly by applying an impulse to the respective inks
Implementation Method 2
the respective color inks each satisfy a mass ratio relationship of S/W ≥ 1, and the black ink satisfies a mass ratio relationship of S/W < 1
Data Source
Figure 1
Figure 2
AI summary
An inkjet recording ink set including a black ink and color inks, wherein the black ink and the color inks each contain at least a dye, a water-soluble solvent and water and each have a viscosity of 5 mPa-s to 20 mPa-s at 25°C, and wherein the respective color inks each satisfy a mass ratio relationship of S/W = 1, and the black ink satisfies a mass ratio relationship of S/W < 1, where S denotes an amount of the water-soluble solvent contained in the respective inks, and W denotes an amount of the water contained in the respective inks.