Ink Set With Water-Soluble Resins For Granularity Control
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving high image quality, particularly in medium to low density areas, due to ink bleed and insufficient image quality caused by low pigment content in thin inks, leading to reactivity issues with process liquids.
Innovation Solution
An ink set comprising a process liquid with a flocculant, a thick ink composition with high pigment content, and a thin ink composition with lower pigment content, where the thin ink is mixed with a 5% calcium propionate solution at a specific ratio to increase viscosity, and includes pigments dispersed with block copolymer resins and water-soluble resins like maleic acid, acrylic, and urethane resins to enhance aggregation and reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin ink is used to reduce granularity in light-colored portions, then granularity is reduced, but ink bleed occurs and image quality becomes insufficient
Solution Approach 1:
The patent changes the chemical parameters of the thin ink by incorporating specific water-soluble resins (maleic acid resin, acrylic resin, or urethane resin) that react with the process liquid to form a gel structure. This chemical modification allows the thin ink to achieve both low granularity and sufficient reactivity, resolving the contradiction between granularity control and image quality.
Solution Approach 2:
The patent creates a composite system by combining thin ink containing specific water-soluble resins with a process liquid containing a flocculant. The interaction between the resin components and the flocculant forms a gel structure that simultaneously achieves fine granularity and prevents ink bleed, resolving the quality contradiction.
2Manufacturing precision
If thin ink with lower pigment content is used, then granularity is reduced, but reactivity with process liquid becomes low
Solution Approach 1:
The patent modifies the chemical composition parameters of the thin ink by incorporating water-soluble resins (maleic acid resin, acrylic resin, or urethane resin) that provide functional groups capable of reacting with the process liquid. This allows the thin ink to maintain low pigment content for fine granularity while achieving sufficient reactivity through the resin-process liquid interaction.
Solution Approach 2:
The water-soluble resins act as intermediaries between the low-pigment thin ink and the process liquid. These resins provide the necessary chemical functionality for reaction with the process liquid, enabling the thin ink to achieve both low granularity and adequate reactivity without relying solely on pigment content.
3Reliability
If thick ink is used to improve reactivity with process liquid, then reactivity is enhanced, but granularity increases in light-colored portions
Solution Approach 1:
The patent segments the ink system into two distinct components: thick ink for high-density areas requiring high reactivity, and thin ink with water-soluble resins for light-colored areas requiring fine granularity. The thin ink's resin components provide the necessary reactivity without the granularity problems of conventional thick ink, allowing each area to use the appropriate ink type.
Solution Approach 2:
The patent applies different ink compositions to different recording density areas: thin ink with water-soluble resins is used for light-colored portions where fine granularity is critical, while thick ink is used for dark portions where high reactivity is more important. This local differentiation resolves the contradiction between reactivity and granularity control.
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 improves image quality by reducing ink bleed, enhancing color development, and providing better fixability and friction resistance, especially in medium to low density areas, while maintaining excellent image quality and stability.
Implementation Method 1
a process liquid containing a flocculant
Implementation Method 2
the pigment is dispersed with a dispersant resin, and the dispersant resin is a block copolymer including a block having a carboxy group and a block not having a carboxy group
Implementation Method 3
the dispersant resin is a block copolymer including a block having a carboxy group
Data Source
AI summary
An ink set includes a process liquid containing a flocculant; a first ink composition that contains a color material, is a thick ink, and is an aqueous ink; and a second ink composition that contains a color material, the content of the color material being smaller than that of the color material in the first ink composition, is a thin ink in a similar color to that of the first ink composition, and is an aqueous ink. When the second ink composition and a 5 mass % aqueous solution of calcium propionate are mixed at a mass ratio of “the former: the latter=10:1”, the viscosity increasing rate of the former is 2.2 times or more. The second ink composition satisfies one or more of the following requirements (1) and (2): (1) containing a pigment as the color material, wherein the pigment is dispersed in a dispersant resin, and the dispersant resin is a block copolymer including a block having a carboxy group and a block not having a carboxy group; and (2) containing one or more of maleic acid, acrylic, and urethane water-soluble resins that are soluble in a solvent component of the ink.