Ink Additive Combinations for Printhead Lifetime

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Solution Overview

Problem

Memjet printheads, particularly those with uncoated resistive heater elements, face short lifetimes due to aggressive inks, especially dye-based inks that corrode the heater elements, leading to reduced print quality and premature failure.

Innovation Solution

A synergistic combination of anti-kogation and anti-corrosion additives, such as ethoxylated butyne-1,2-diols and ethoxylated glycerol, is used in inkjet inks to protect thermal actuators, extending printhead lifetime without significantly affecting ink viscosity or surface tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If uncoated heater elements are used, then heat transfer efficiency is improved, but printhead lifetime is reduced due to corrosion from aggressive inks

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidprinthead lifetime
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a protective coating layer as an intermediary between the heater element and the aggressive ink. This coating acts as a mediator that prevents direct contact between corrosive ink components and the heater element, thereby extending printhead lifetime while maintaining adequate heat transfer efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material structures for the protective coating, combining multiple materials with complementary properties. The coating system integrates corrosion-resistant materials with thermally conductive materials to simultaneously achieve protection against ink corrosion and maintain heat transfer efficiency.

Inventive Principle:
Principle #40Composite materials

2Reliability

If protective coating is applied to heater elements, then printhead lifetime is improved, but heat transfer efficiency is reduced

Engineering Contradiction:
Improveprinthead lifetimeVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent utilizes thin film protective coatings that provide corrosion protection while minimizing thermal resistance. The thin film structure allows heat to conduct through the coating with minimal impedance, maintaining heat transfer efficiency while providing sufficient protection against ink corrosion.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent optimizes coating parameters including thickness, composition, and thermal conductivity to achieve the desired balance between protection and heat transfer. By carefully controlling these parameters, the coating provides adequate corrosion protection while maintaining acceptable heat transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If dye-based inks are used, then print quality is improved, but heater element corrosion increases reducing printhead lifetime

Engineering Contradiction:
Improveprint qualityVSAvoidprinthead lifetime
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent converts the harmful corrosive effect of dye-based inks into a benefit by using the ink's own components in controlled concentrations. The formulation includes specific dye concentrations and complementary additives that, when properly balanced, reduce corrosion while maintaining print quality.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent modifies ink formulation parameters including dye concentration, pH, and additive composition to reduce corrosion. By carefully adjusting these parameters, the ink maintains its color performance while becoming less aggressive towards heater elements.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If anti-corrosion additives are added to ink, then heater element protection is improved, but ink viscosity and surface tension are affected

Engineering Contradiction:
Improveheater element protectionVSAvoidink formulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs additives that perform multiple functions simultaneously. The selected additives provide corrosion protection while also serving as humectants, viscosity modifiers, or surface tension regulators, thereby reducing the need for additional separate additives and simplifying the overall formulation.

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

Solution Approach 2:

The patent combines multiple functions into single additive components. By selecting additives that can simultaneously protect against corrosion and perform other necessary ink functions, the formulation complexity is reduced while achieving the desired heater element protection.

Inventive Principle:
Principle #5Merging (Combining)

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 additive combination significantly extends printhead lifetime by 2.5 times compared to using either additive alone, maintaining print quality and reducing the impact on ink characteristics, demonstrating a synergistic effect that improves robustness and efficiency.

Implementation Method 1

anti-corrosion additives, such as ethoxylated butyne-1,2-diols and ethoxylated glycerol, is used in inkjet inks to protect thermal actuators

Methodology Applied
Scientific EffectAnti-corrosion:

Implementation Method 2

anti-kogation and anti-corrosion additives, such as ethoxylated butyne-1,2-diols and ethoxylated glycerol

Methodology Applied
Scientific EffectAnti-kogation: Surfactant

Data Source

PatentEP3204458B1Ink additive combinations for improving printhead lifetime
Publication Date: 2018.09.26 MEMJET TECH LTD
  • EP3204458B1 patent drawingFigure 1
  • EP3204458B1 patent drawingFigure 2~3
  • EP3204458B1 patent drawingFigure 4

AI summary

An inkjet ink for improving printhead lifetimes includes: an aqueous-based ink vehicle; a colorant; an anti-kogation additive; and an anti-corrosion additive having at least one acetylenic group, the acetylenic group being absent any tertiary or quaternary α-carbon atoms.