Ink Composition Pigment Surface Area Control

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Solution Overview

Problem

Current pigment-containing ink compositions for ink jet printing face challenges in dispersion stability and control of coarse pigment particles, leading to instability and reduced print quality, especially at higher speeds and with increased durability demands.

Innovation Solution

An ink composition containing water, a surfactant, and a pigment with a specific surface area between 10 m2/g and 50 m2/g, as determined by pulsed NMR, which ensures stable dispersion and reduced agglomeration of pigments, enhancing ejection stability and print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pigment-containing ink compositions are used for ink jet printing, then color stability and print quality are improved, but dispersion stability deteriorates and coarse pigment particles form during water evaporation

Engineering Contradiction:
Improveprint stabilityVSAvoiddispersion stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the specific surface area of pigment particles within 10-50 m2/g and adjusting the HLB value of nonionic surfactants to match the pigment's specific surface area according to the formula 0.15≤H−(Sp×0.25)≤3.75. This optimization of physical parameters prevents pigment agglomeration during water evaporation while maintaining stable dispersion in the ink composition, thereby resolving the contradiction between print stability and dispersion stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces nonionic surfactants as intermediary substances that mediate between pigment particles and water. The surfactant's HLB value is specifically matched to the pigment's specific surface area, creating a stable interface that prevents direct contact and agglomeration of pigment particles during the evaporation process. This intermediary action maintains dispersion stability while ensuring reliable print quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If ink jet printing operates at higher speeds with increased durability demands, then productivity is improved, but print stability deteriorates due to coarse particle formation

Engineering Contradiction:
Improveprinting speedVSAvoidprint stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent optimizes the parameter of specific surface area to 10-50 m2/g and establishes a quantitative relationship between surfactant HLB value and pigment specific surface area. This parameter optimization ensures that pigment particles remain stably dispersed even under high-speed printing conditions with increased water evaporation, thereby maintaining print stability while achieving high productivity.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If water evaporates from the ink composition on the ejection nozzle surface, then ink deposition is improved, but pigment agglomeration increases reducing ejection stability

Engineering Contradiction:
Improveink depositionVSAvoidejection stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses nonionic surfactants as intermediary substances that remain effective during water evaporation on the nozzle surface. The surfactant molecules form protective layers around pigment particles, preventing agglomeration even as water evaporates and pigment concentration increases. This intermediary protection maintains ejection stability while ensuring proper ink deposition on the substrate.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 composition achieves high print stability and fastness, with reduced formation of coarse particles, resulting in superior ejection reliability and high-quality prints with improved durability and speed.

Implementation Method 1

The specific surface area of the pigment as determined by pulsed NMR at 30° C. is 10 m2/g or more and 50 m2/g or less

Methodology Applied
Scientific EffectPulsed NMR: Electron Paramagnetic Resonance

Implementation Method 2

When an ink composition according to an aspect of the invention is ejected, for example by ink jetting, the water in the ink composition evaporates on the surface of the ejection nozzles

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10633548B2Ink composition and recording method
Publication Date: 2020.04.28 SEIKO EPSON CORP

AI summary

An ink composition contains water, at least one surfactant, and a pigment. The pigment has a specific surface area of 10 m2/g or more and 50 m2/g or less as determined by pulsed NMR at 30° C.