Ink Set Segmentation for Fast Drying and Bleeding Prevention
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Solution Overview
Problem
Current inkjet recording methods face challenges in producing high-speed, high-resolution color images with minimal bleeding at color boundaries on regular paper with poor ink absorbability or on coating mediums without an aqueous ink-receiving layer, especially when using inks with high pigment concentration or solid content.
Innovation Solution
An ink set comprising two aqueous inks with different colors, where one ink contains a water-dispersible colorant without a surfactant-based dispersant and the other contains a surfactant-based dispersant, allowing for aggregation and forming a sharp image with specific ratios of water-dispersible colorants and anionic compounds, along with the use of wetting agents and surfactants to enhance wettability and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If ink permeability is enhanced to increase ink dry speed, then drying time is reduced, but bleeding occurs in the printed image
Solution Approach 1:
The patent applies different types of colorants (pigment-based vs. dye-based) to different ink components (black ink vs. color inks) to create local quality differences. Black ink uses pigment-based colorants with low permeability to prevent bleeding, while color inks use dye-based colorants with higher permeability for fast drying, achieving both fast drying and bleeding prevention in different regions of the printed image
Solution Approach 2:
The ink set is segmented into different components (black ink and color inks) with different properties. Black ink is formulated with pigment-based colorants and specific binders for low permeability, while color inks use dye-based colorants for higher permeability, allowing each segment to optimize its function without compromising the other
2Manufacturing precision
If multi-pass printing is employed to suppress ink permeation and increase image density, then image density is improved, but printing speed is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the inks, specifically the ratio of binder to colorant and the type of colorant used. Black ink uses a high binder content (5-20 parts by weight per 100 parts colorant) with pigment-based colorants to control permeability, while color inks use dye-based colorants with different binder ratios, allowing single-pass printing with appropriate image density without requiring multiple passes
3Object-generated harmful factors
If pigment-based ink is used to suppress permeability and increase image density, then bleeding is prevented, but water resistance and light resistance are reduced in two-color composite portions
Solution Approach 1:
The patent applies different colorant types locally: pigment-based colorants in black ink for bleeding prevention and dye-based colorants in color inks for better water and light resistance. This local differentiation allows each ink type to optimize its properties for its specific function
Solution Approach 2:
The ink set uses composite formulations combining different colorant types (pigment and dye) with specific binders and additives. The black ink is a composite of pigment-based colorant, binder, and water, while color inks are composites of dye-based colorant, binder, and water, creating materials with optimized properties for their respective functions
4Duration of action of moving object
If dye-based inks are used with high permeability for fast drying, then ink dry speed is improved, but bleeding occurs at boundaries between black and other colors
Solution Approach 1:
The ink set is segmented into black ink using pigment-based colorants with low permeability and color inks using dye-based colorants with higher permeability. This segmentation allows color inks to dry quickly while black ink provides a bleeding-resistant base, preventing bleeding at color boundaries
Solution Approach 2:
Different permeability characteristics are assigned locally to different ink components. Black ink has low permeability to prevent bleeding, while color inks have higher permeability for fast drying. This local quality differentiation resolves the contradiction between fast drying and bleeding prevention at color boundaries
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 enables high-speed printing of sharp, high-resolution color images with reduced bleeding and improved storage stability, ensuring excellent image formation on regular paper with poor ink absorbability or on coating mediums without an aqueous ink-receiving layer.
Implementation Method 1
the inks A and B undergo aggregation when homogenously mixed and retained at 25°C for 60 minutes
Implementation Method 2
the ink B contains water-dispersible colorant B1 containing a surfactant-based dispersant
Implementation Method 3
along with the use of wetting agents and surfactants to enhance wettability and permeability
Data Source
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AI summary
An ink set includes at least two aqueous inks A and B with different colors, the inks A and B used in an inkjet recording method in which the inks A and B are superimposed for formation of a color image, wherein the ink A contains water-dispersible colorant A1 free of a surfactant-based dispersant, and anionic compound A2, and wherein the ink B contains water-dispersible colorant B1 containing a surfactant-based dispersant.