Ink Composition Using Colloidal Silica and Urea for Inkjet Head Maintenance

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Solution Overview

Problem

Aqueous ink compositions for inkjet recording face challenges in maintaining fluidity, storage stability, glossiness, and pigment dispersibility, with existing solutions failing to provide quality comparable to oil-based inks and often leading to deteriorated maintenance properties and liquid repellency issues in inkjet head members.

Innovation Solution

An ink composition comprising colloidal silica, urea, and a pigment in water, which enhances maintenance properties and suppresses the lowering of liquid repellency in inkjet head members, using colloidal silica with a specific particle diameter range and urea content to improve removability and image fixability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional dispersion methods are used for pigments in aqueous vehicles, then the ink composition can be prepared, but pigment dispersibility and adaptability remain markedly poor

Engineering Contradiction:
Improvepigment dispersibilityVSAvoidadaptability to aqueous vehicles
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent introduces a specific resin emulsion as an intermediary substance between the pigment and aqueous vehicle. This resin emulsion contains functional groups that interact with both the pigment particles and the water-based medium, improving pigment dispersibility and adaptability simultaneously. The resin acts as a bridge that mediates the interaction between incompatible components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite ink composition by combining multiple components: resin emulsion, inorganic oxide colloid, pigment, and aqueous vehicle. This composite approach allows each component to contribute specific properties - the resin provides dispersibility, the inorganic oxide enhances stability, and together they achieve adaptability comparable to oil-based inks while maintaining the benefits of aqueous formulation.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If aqueous ink composition is used, then environmental protection and resource conservation are improved, but maintenance properties and liquid repellency of inkjet head members deteriorate

Engineering Contradiction:
Improveenvironmental impactVSAvoidmaintenance properties
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent modifies key parameters of the aqueous ink composition, specifically adjusting the resin emulsion concentration (1-20 mass%), inorganic oxide colloid content (0.1-10 mass%), pH value (4-9), and surface tension (20-60 mN/m). These parameter optimizations maintain environmental benefits while significantly improving maintenance properties and reducing liquid repellency issues in inkjet heads.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality improvement by adding inorganic oxide colloid particles that specifically accumulate at the inkjet head surface to enhance liquid repellency where needed, while the bulk ink composition remains environmentally friendly aqueous formulation. This localized enhancement addresses maintenance issues without compromising the overall green chemistry approach.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If resin emulsion and inorganic oxide colloid are added to improve pigment dispersibility, then adaptability improves, but device complexity increases

Engineering Contradiction:
Improvepigment adaptabilityVSAvoidcomposition complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves multi-functionality by selecting a resin emulsion that simultaneously provides pigment dispersibility, ink stability, and adhesion properties. The same resin emulsion and inorganic oxide colloid combination serves multiple functions: dispersing pigment, stabilizing the aqueous medium, and improving inkjet head maintenance properties, thereby reducing the need for multiple separate additives.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 excellent maintenance properties and maintains ink ejection performance by effectively suppressing the lowering of liquid repellency in inkjet head members, ensuring better removability of adhered components and improved image quality.

Implementation Method 1

lowering of liquid repellency of an inkjet head member

Methodology Applied
Scientific EffectLiquid repellency: Hydrophobe

Implementation Method 2

improve removability of adhered components

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2366745B1Ink composition, ink set and inkjet image forming method
Publication Date: 2016.12.07 FUJIFILM CORP
  • EP2366745B1 patent drawingFigure 1
  • EP2366745B1 patent drawingFigure 2
  • EP2366745B1 patent drawing

AI summary

The present invention provides an ink composition for inkjet recording, containing colloidal silica, urea, a coloring material, and water.