Inkjet Recording Method for Suppressing Color Bleeding
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Solution Overview
Problem
Ink jet recording methods using aqueous ink compositions with microcapsules face issues with color bleeding and uneven fixation due to differences in evaporation rates and absorbance, particularly when combining multiple colors, leading to poor image quality and spreading of ink droplets.
Innovation Solution
An ink jet recording method that involves jetting ink compositions A and B onto a substrate, where composition A contains a polymerizable compound, high boiling solvent, water, and a colorant, and composition B contains a polymerizable compound, high boiling solvent, and carbon black, with specific absorbance and concentration ratios to control evaporation and aggregation of microcapsules, ensuring uniform fixation and minimizing color bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If aqueous ink compositions with different colorants are used for multi-color printing, then color variety is improved, but evaporation rate uniformity deteriorates due to different absorbance at 800-1400 nm wavelengths
Solution Approach 1:
The patent adjusts the high boiling solvent concentration parameter in each ink composition to compensate for different absorbance characteristics of colorants. By changing this concentration parameter, the evaporation rates of different colored inks are equalized during infrared heating, ensuring uniform fixation across all colors despite their different optical properties
Solution Approach 2:
The patent applies different high boiling solvent concentrations to different ink compositions based on their specific colorant absorbance characteristics. Each ink formulation is locally optimized with a specific solvent concentration tailored to its absorbance properties, creating a customized solution for each color while maintaining overall system compatibility
2Quantity of substance
If black ink containing carbon black is used, then color absorption is improved, but microcapsule destruction increases due to excessive heat generation
Solution Approach 1:
The patent reduces the high boiling solvent concentration in black ink containing carbon black compared to other colors. This parameter adjustment lowers the infrared absorption and heat generation in black ink regions, preventing microcapsule destruction while maintaining adequate color absorption through the carbon black pigment
Solution Approach 2:
The patent converts the harmful heat-generating property of carbon black into a beneficial control mechanism. By deliberately reducing the high boiling solvent concentration in black ink, the excessive heat absorption by carbon black is counterbalanced, transforming a potential source of microcapsule destruction into a controlled parameter that ensures uniform fixation without damage
3Manufacturing precision
If conventional heating is applied to multi-color ink compositions, then fixation is achieved, but color bleeding occurs due to differential evaporation rates
Solution Approach 1:
The patent changes the high boiling solvent concentration parameter in each ink composition to equalize evaporation rates during heating. This parameter adjustment ensures that all color inks evaporate and fix at the same rate under identical heating conditions, achieving uniform fixation while preventing color bleeding between adjacent ink regions
Solution Approach 2:
The patent creates equipotential conditions for evaporation across different ink compositions by adjusting their high boiling solvent concentrations. This ensures that all ink types have equal evaporation potential under the same heating conditions, eliminating the differential evaporation that causes color bleeding and achieving uniform fixation across the entire printed image
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 method effectively suppresses color bleeding and ensures uniform fixation of ink droplets, resulting in improved image quality and stability by controlling the evaporation rates and aggregation of microcapsules, even when combining multiple colors.
Implementation Method 1
an ink jet recording method in which, after ink jetted on a substrate is heated by being irradiated with infrared rays
Implementation Method 2
an evaporation rate of water in the ink composition is different in a heating step
Implementation Method 3
an ink jet ink that can be cured by being irradiated with active energy rays such as ultraviolet rays
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is an ink jet recording method, including a step of jetting, on a substrate, an ink composition A that contains a microcapsule having at least a polymerizable compound within the microcapsule, a high boiling solvent, water, and a colorant, and an ink composition B that contains a microcapsule having at least a polymerizable compound within the microcapsule, a high boiling solvent, water, and carbon black; and a step of heating the ink composition A and the ink composition B which have been jetted on the substrate, in which absorbance ABSA of the ink composition A and absorbance ABSB of the ink composition B satisfy Formula (1), and a concentration MA of the high boiling solvent contained in the ink composition A and a concentration MB of the high boiling solvent in the ink composition B satisfy Formula (2). ABSA<ABSB MA<MB