Ink Formulation with Acryl Polymer for Stable Inkjet Discharge

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Solution Overview

Problem

Inkjet recording methods using thermal energy face challenges in achieving high discharge stability and highlighter resistance, particularly when using polyurethane polymers with acid values above 30 mg KOH/g and self-dispersing carbon black, as these lead to deposition on the recording head, causing reduced discharge speed and image distortion.

Innovation Solution

Incorporating an acryl polymer with an acid value between 100 mg KOH/g and 200 mg KOH/g into the ink, which balances the cohesive force of the polyurethane polymer with the carbon black, preventing deposition on the recording head and maintaining discharge stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polyurethane polymer with an acid value above 30 mg KOH/g is used to enhance highlighter resistance, then the highlighter resistance on the image is improved, but the ink discharge stability deteriorates due to deposition on the recording head

Engineering Contradiction:
Improvehighlighter resistanceVSAvoiddischarge stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the acid value parameter of the polyurethane polymer from above 30 mg KOH/g to 100-200 mg KOH/g, which fundamentally alters the polymer's chemical properties. This parameter change reduces the polymer's tendency to deposit on the recording head while maintaining sufficient highlighter resistance, thereby resolving the contradiction between discharge stability and highlighter resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining polyurethane polymer (100-200 mg KOH/g acid value) with self-dispersing carbon black pigment. This composite material achieves synergistic effects where the modified polyurethane polymer provides both adequate highlighter resistance and improved discharge stability by preventing pigment deposition on the recording head

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If the cohesive force of the polyurethane polymer with carbon black is increased to improve image density, then the optical density is enhanced, but deposition on the recording head increases causing discharge speed reduction

Engineering Contradiction:
Improveoptical densityVSAvoiddischarge speed
Core Design Contradiction:
Illumination intensityVSSpeed

Solution Approach 1:

The patent modifies the acid value parameter of the polyurethane polymer to 100-200 mg KOH/g, which changes the polymer's surface chemistry and interaction characteristics with carbon black pigment. This parameter adjustment maintains sufficient cohesive force for adequate optical density while reducing excessive adhesion to the recording head, thereby preserving discharge speed

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If self-dispersing carbon black is used to enhance optical density, then the image density is improved, but the ink discharge stability deteriorates due to deposition on the recording head

Engineering Contradiction:
Improveoptical densityVSAvoiddischarge stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent formulates a composite ink system combining self-dispersing carbon black with polyurethane polymer having 100-200 mg KOH/g acid value. This composite formulation achieves optimal balance where the carbon black provides high optical density while the modified polyurethane polymer prevents aggregation and deposition on the recording head, maintaining discharge stability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the acid value parameter of the polyurethane polymer to 100-200 mg KOH/g, which fundamentally alters the dispersant's chemical properties. This parameter change enhances the polymer's ability to stabilize carbon black particles in suspension, preventing deposition on the recording head while maintaining high optical density

Inventive Principle:
Principle #35Parameter changes

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 acryl polymer effectively reduces the cohesive force of the polyurethane polymer, preventing carbon black deposition and maintaining discharge stability, while enhancing highlighter resistance by ensuring the carbon black is discharged with the ink, thus preventing image distortion and maintaining high-quality image production.

Implementation Method 1

the acryl polymer effectively reduces the cohesive force of the polyurethane polymer, preventing carbon black deposition

Methodology Applied
Scientific EffectCohesive force reduction: Cohesion

Implementation Method 2

an ink is discharged from a recording head by an action of thermal energy

Methodology Applied
Scientific EffectThermal energy action: Heating

Implementation Method 3

an ink is discharged from a recording head by an action of thermal energy

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP2662421B1Ink, ink cartridge, and inkjet recording method
Publication Date: 2018.01.31 CANON KK
  • EP2662421B1 patent drawingFigure 1
  • EP2662421B1 patent drawingFigure 2
  • EP2662421B1 patent drawing

AI summary

An ink used for an inkjet recording method for discharging the ink from a recording head by an action of thermal energy contains self-dispersing carbon black, a polyurethane polymer having an acid value of 40 mg KOH/g or more, and an acryl polymer having an acid value of 100 mg KOH/g or more and 200 mg KOH/g or less.