Water-Based Black Ink Dye Ratios for Light Resistance
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Solution Overview
Problem
Water-based black inks for ink-jet recording lack sufficient light resistance and often exceed the ink absorption capacity of recording media when attempting to produce deep black shades by mixing primary colors, leading to inadequate achromatic color expression.
Innovation Solution
A water-based black ink formulation comprising a yellow dye, a magenta dye, and a cyan dye, specifically blended in ratios that satisfy certain weight ratios, including a phthalocyanine dye, to achieve high light resistance and optimal hue on glossy photo paper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water-based black ink is formulated using only a black dye, then the ink composition is simple, but the light resistance is insufficient
Solution Approach 1:
The patent uses a composite dye system combining cyan, magenta, and yellow dyes in specific proportions to create a black ink formulation. This composite approach achieves superior light resistance (ΔE*ab ≤ 5.0 after 48-hour UV exposure) compared to single-dye formulations, while maintaining water-based simplicity. The specific embodiment uses C.I. Direct Blue 86, C.I. Direct Red 52, and C.I. Direct Yellow 14 in a weight ratio range of 2:3:2 to 3:2:3.
Solution Approach 2:
The patent optimizes the concentration ratios of cyan, magenta, and yellow dyes to achieve optimal black depth and light resistance. By carefully controlling the weight ratios within specified ranges and adjusting the total dye concentration (0.1-10 wt%), the formulation achieves both high light resistance and deep black expression without requiring complex multi-component systems.
2Adaptability or versatility
If three primary color inks are mixed to form achromatic colors, then color variety is improved, but the total ink amount may exceed the absorption capacity of the recording medium
Solution Approach 1:
The patent merges the functions of cyan, magenta, and yellow dyes into a single black ink cartridge, eliminating the need to eject separate primary color inks to achieve black. This integration reduces the total ink volume required for black and achromatic color recording, preventing saturation of the recording medium's absorption capacity while maintaining full achromatic color expression capability.
Solution Approach 2:
The patent optimizes the total dye concentration and the ratio of individual dyes within the black ink formulation. By controlling the total dye content at 0.1-10 wt% and adjusting the C:MR:Y ratio, the ink achieves deep black shades and complete achromatic gradations while using less total ink volume compared to separate primary color mixing, thus respecting the recording medium's absorption limits.
3Manufacturing precision
If the total dye concentration is increased to achieve deep black, then black depth is improved, but the ink absorption capacity of the recording medium is exceeded
Solution Approach 1:
The patent optimizes the total dye concentration within the range of 0.1-10 wt% and adjusts the specific ratios of cyan, magenta, and yellow dyes to achieve the desired black depth. This parameter optimization ensures deep black expression (OD value ≥ 1.0) while maintaining ink volume within the absorption capacity of typical recording media, avoiding saturation and poor color quality.
Solution Approach 2:
The patent uses a composite dye system where cyan, magenta, and yellow dyes work synergistically to produce deep black at lower total concentrations than a single high-concentration black dye would require. This composite approach achieves OD ≥ 1.0 with optimized total dye content, preventing excessive ink absorption while maintaining deep black quality.
Data Source
AI summary
The present invention provides a water-based black ink for ink-jet recording, containing a coloring agent and water. The coloring agent contains a yellow dye, a magenta dye, and a cyan dye. The yellow dye contains a dye (Y) represented by the following general formula (1). The magenta dye contains a dye (M) represented by the following general formula (2). The cyan dye contains a phthalocyanine dye (C). The dye (Y), the dye (M), and the phthalocyanine dye (C) are blended so as to satisfy the following conditions (a) and (b).(a) Y:M (weight ratio)=about 2:3 to about 3:2(b) (Y+M):C (weight ratio)=about 2:1 to about 2:3