Aqueous Ink Composition for Nozzle Decapping and Image Ruggedness

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing aqueous inks for inkjet recording face challenges in maintaining ink ejection properties, ruggedness, and decapping properties while adhering to VOC regulation standards, often leading to nozzle clogging and image clarity issues due to solvent evaporation and viscosity adjustments.

Innovation Solution

An aqueous ink formulation with specific solvent and thickener ratios, including a binder polymer, maintains viscosity between 10-14 mPa·s, and incorporates a solvent group with controlled evaporation to prevent nozzle clogging, ensuring ink ejection and image quality without violating VOC regulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the viscosity of the aqueous ink is increased to improve ruggedness, then the image quality becomes sharper, but the ink ejection property deteriorates and the nozzle is more likely to be clogged

Engineering Contradiction:
Improveimage quality (ruggedness)VSAvoidink ejection property
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the viscosity within the range of 10 to 14 mPa·s and regulating the solvent group A content at 25.0-30.0 wt%, thereby optimizing both image quality and ink ejection properties simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite ink formulation combining water, solvent group A, thickener, and binder polymer in specific proportions to achieve a balance between viscosity for image quality and fluidity for ejection

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If the viscosity of the aqueous ink is increased to improve ruggedness, then the image quality becomes sharper, but the decapping property deteriorates due to quick drying of the ink attached to the nozzle

Engineering Contradiction:
Improveimage quality (ruggedness)VSAvoiddecapping property
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent controls the solvent group A content at 25.0-30.0 wt% to regulate evaporation rate, preventing quick drying of ink on the nozzle while maintaining sufficient viscosity for sharp images

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a thickener as an intermediary substance that increases viscosity for image quality without causing rapid drying, thereby protecting the nozzle from clogging

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the solvent ratio is increased to improve ink ejection property, then the viscosity is reduced and ejection becomes easier, but the VOC regulation standard may be violated and the ink dries quickly causing nozzle clogging

Engineering Contradiction:
Improveink ejection propertyVSAvoidVOC regulation compliance and decapping property
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent precisely controls the solvent group A content at 25.0-30.0 wt%, which is sufficient for good ejection properties while remaining below the VOC regulation limit of 30.0 wt%

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses water as the base solvent and supplements with controlled amounts of solvent group A, creating an ink formulation that achieves ejection performance without relying on high VOC content

Inventive Principle:
Principle #26Copying

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 retains ink ejection properties, ruggedness, and decapping properties, preventing nozzle clogging and ensuring clear images while adhering to environmental regulations.

Implementation Method 1

A viscosity of the aqueous ink is 10 mPa·s to 14 mPa·s. The viscosity of the aqueous ink is adjusted to 10 mPa·s or more by the thickener, and thus, an image formed by the ink is hard to become unclear.

Methodology Applied
Scientific EffectViscosity adjustment:

Implementation Method 2

A weight percent of the solvent group A in the total amount of the aqueous ink is 25.0 wt% to 30.0 wt%. The weight percent of the solvent group A in the total amount of the aqueous ink is 30.0 wt% or less, and thus the aqueous ink does not violate a VOC regulation standard.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

The binder polymer may be a polymer in which a low viscosity binder polymer dispersion liquid containing the polymer has a viscosity of 10 mPa·s to less than 100 mPa·s when the polymer is added to a low viscosity binder polymer dispersion medium so as to be 38.0 wt% in the low viscosity binder polymer dispersion liquid.

Methodology Applied
Scientific EffectFilm formation:

Data Source

PatentEP4660261A1Aqueous ink, ink ejection device, image recording device and printing method
Publication Date: 2025.12.10 BROTHER KOGYO KK
  • EP4660261A1 patent drawingFigure 1
  • EP4660261A1 patent drawingFigure 2
  • EP4660261A1 patent drawingFigure 3

AI summary

An aqueous ink retaining an ink ejection property, ruggedness, and a decapping property without violating a VOC regulation standard, is provided. An aqueous ink contains water, a solvent group A having a weight change amount of more than 0.01 g when 1.5 g ± 0.1 g of the solvent group A is placed in an upwardly opened aluminum foil box of 40 mm × 40 mm × 10 mm and heated at a temperature of 100°C ± 5°C for 30 minutes indoors at a room temperature of 25°C and a humidity of 65%, a thickener, and a binder polymer. A weight percent of the solvent group A in the total amount of the aqueous ink is 25.0 wt% to 30.0 wt%. A weight percent of the thickener in the total amount of the aqueous ink is 10.1% or more. A viscosity of the aqueous ink is 10 mPa·s to 14 mPa·s.