Non-aqueous Maintenance Liquid for Inkjet Nozzle Clogging

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Solution Overview

Problem

Current cleaning and preserving liquids for active energy ray-curable inkjet printing fail to maintain ink concentration and nozzle water repellency, leading to clogging and jetting failures due to pigment aggregation and surface energy issues.

Innovation Solution

A non-aqueous cleaning liquid comprising a main organic solvent or active energy ray-curable compound, a pigment dispersant resin, and a surface control agent, specifically including glycol monoacetates, polyalkyleneimine-based resins, and silicone or fluorinated surfactants, to stabilize pigment dispersion and maintain nozzle water repellency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current cleaning liquids are used to remove ink, then cleaning ability is improved, but pigment dispersion is disturbed leading to nozzle clogging

Engineering Contradiction:
Improvecleaning abilityVSAvoidpigment dispersion
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the cleaning liquid by specifying precise compositional ratios (maintaining ink at 5-50 wt% after cleaning, using specific solvents like glycol monoacetate or lactate). This controlled parameter change ensures the cleaning liquid effectively removes ink while maintaining pigment dispersion stability, preventing nozzle clogging during the cleaning process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite cleaning liquid formulation combining multiple components: ink, specific solvents (glycol monoacetate, glycol diacetate, lactate, etc.), and surface control agents. This composite material approach creates a synergistic effect where each component contributes to both cleaning effectiveness and pigment dispersion stability, resolving the contradiction between cleaning ability and dispersion maintenance.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If maintenance liquid is used to preserve the head during storage, then preserving capability is improved, but nozzle water repellency deteriorates due to pigment adhesion

Engineering Contradiction:
Improvepreserving capabilityVSAvoidnozzle water repellency
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent changes the surface energy parameters of the nozzle plate by incorporating specific surface control agents in controlled amounts (0.01-5 wt%). These agents modify the nozzle surface properties to maintain water repellency during storage. The parameter control ensures that even during extended storage with dilute ink, the nozzle surface maintains its hydrophobic characteristics, preventing pigment adhesion and maintaining jetting reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces surface control agents as intermediary substances that mediate between the pigment particles and the nozzle plate surface. These agents prevent direct adhesion of pigments to the nozzle surface while maintaining the preserving liquid's effectiveness. The surface control agents act as a protective intermediary layer, preserving nozzle water repellency during storage periods.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If dispersant resin is added to maintenance liquid to stabilize pigment dispersion, then dispersion stability is improved, but excess resin adsorbs to nozzle plate reducing jetting stability

Engineering Contradiction:
Improvepigment dispersion stabilityVSAvoidjetting stability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent precisely controls the concentration parameters of dispersant resins in the maintenance liquid, specifying narrow ranges (0.01-5 wt%) to optimize the balance between dispersion stability and jetting stability. By controlling the resin concentration within this specific parameter range, the patent ensures sufficient pigment dispersion stability while preventing excess resin adsorption that would compromise nozzle water repellency and jetting stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the functional roles of dispersant resins and surface control agents in different locations within the system. Dispersant resins primarily act on pigment particles to maintain dispersion, while surface control agents specifically target the nozzle plate surface to maintain water repellency. This localized functional differentiation resolves the contradiction by assigning specific tasks to specific components.

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 provides excellent cleaning ability, prevents nozzle clogging, ensures continuous jettability, and maintains storage stability by stabilizing pigment dispersion and preserving nozzle water repellency.

Implementation Method 1

a pigment dispersant resin, and a surface control agent... to stabilize pigment dispersion

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

the pigment surface following the disturbance of the dispersion is in a state of very high surface free energy, which causes the pigment to adhere not only to the printer and the ink passages within the head, but also strongly to the nozzle plate surface, causing deterioration of the water-repellency of the nozzle plate

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2987638B1Maintenance solution for active energy ray curable inkjet ink
Publication Date: 2020.05.20 TOYO INK MFG CO LTD

AI summary

Provided is a non-aqueous maintenance liquid for an active energy ray-curable inkjet ink which can be used as a cleaning liquid for removing the inkjet ink and as a preserving liquid to fill the head when the printer is not in operation. The non-aqueous maintenance liquid for an active energy ray-curable inkjet ink of the present invention comprises a main liquid component, a pigment dispersant resin, and a surface control agent, wherein the main liquid component is an organic solvent and/or an active energy ray-curable compound, and the amount of the surface control agent is 0.01 to 10% by weight in 100% by weight of the maintenance liquid.