Aqueous Ink Composition Reducing Granularity on Non-Absorbent Media

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Solution Overview

Problem

Inkjet recording methods face challenges with aqueous inkjet inks when printing on less-ink-absorbent or non-ink-absorbent recording media, resulting in granular unevenness and insufficient image fastness, especially when transitioning to ink-absorbent media.

Innovation Solution

An aqueous ink composition combining specific pigments and dyes, such as black pigments with black dyes, cyan pigments with blue dyes, magenta pigments with red dyes, and yellow pigments with yellow dyes, along with acid-modified polypropylene resin and oxidized polyethylene wax, to enhance image fastness and reduce granularity across various recording media types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a pigment and a dye are used in combination as a color material, then granularity is reduced, but image fastness becomes insufficient and ink coating peels off

Engineering Contradiction:
Improvegranularity of ink coatingVSAvoidimage fastness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the concentration ratios of pigment to dye within specific ranges (pigment 0.1-5% by mass, dye 0.01-1% by mass) and adjusting pH (6-9) and ionic strength to optimize the interaction between pigment and dye particles, achieving both reduced granularity and maintained image fastness through precise parameter optimization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining pigment particles and dye molecules in a controlled aqueous medium with specific surfactants and polymers, creating a hybrid color system that leverages the granularity-reducing effect of dyes while maintaining the fastness properties of pigments through synergistic interactions

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If aqueous inkjet ink is printed on less-ink-absorbent or non-ink-absorbent recording medium, then printing capability is expanded, but ink is repelled causing dots to combine and resulting in granular unevenness

Engineering Contradiction:
Improveprinting capability on different mediaVSAvoiduniformity of ink coating
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces surfactants and polymers as intermediary substances that mediate between the aqueous ink and the recording medium surface, reducing surface tension and improving wetting properties to prevent ink repulsion and dot combination on less-ink-absorbent media while maintaining coating uniformity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adjusts physical parameters including surface tension (through surfactant selection), viscosity (through polymer additives), and pH to optimize ink behavior across different recording medium types, enabling consistent printing quality from ink-absorbent to non-ink-absorbent surfaces

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional aqueous inkjet ink is used on ink-absorbent recording medium, then good absorption is achieved, but image fastness is insufficient when subjected to friction and moisture

Engineering Contradiction:
Improveink absorptionVSAvoidimage fastness under friction and moisture
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs composite materials by combining pigment particles with specific polymers and binders that form a protective matrix, creating an ink formulation that maintains good absorption on ink-absorbent media while providing enhanced resistance to friction and moisture through the composite structure

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating different functional zones within the ink coating - the pigment particles provide fastness in critical areas subject to friction and moisture, while the polymer matrix ensures good absorption and uniform distribution, with each component performing its specialized function in the appropriate location

Inventive Principle:
Principle #3Local quality

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 solution achieves reduced granularity and improved image fastness on both less-ink-absorbent and ink-absorbent recording media, ensuring even and uniform ink coatings with high printing density and resistance to friction and moisture.

Implementation Method 1

the aqueous ink composition further contains an oxidized polyethylene wax

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Implementation Method 2

the aqueous ink composition further contains an acid-modified polypropylene resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20220403193A1Aqueous ink composition, ink set, printed material, and method of producing printed material
Publication Date: 2022.12.22 DIC CORP

AI summary

Provided is an aqueous in ink with which the granularity of an ink coating caused in printing on a less-ink-absorbent or non-ink-absorbent recording medium is reduced while sufficient image fastness is achieved even printing on an ink-absorbent recording medium. The present invention relates to an ague-gas ink composition for use in an inkjet recording method. The aqueous ink composition contains an aqueous medium, a pigment, and a dye, and a combination of the pigment and the dye is a predetermined combination.