Ink Composition Surfactants Prevent Bubble Formation

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Solution Overview

Problem

Ink jet recording systems face issues with discharging failures due to bubble formation caused by air contact with deaerated ink in conventional ink tanks and supply methods, leading to poor initial filling characteristics and continuous printing stability.

Innovation Solution

An ink composition containing an alkylene oxide adduct of acetylenic glycol with a main chain of 12 or more carbon atoms, acetylenic glycol with a main chain of 10 or more carbon atoms, and polyoxyalkylene alkyl ether, along with an ink supply system featuring a filter in the ink supply path, which captures bubbles and ensures stable ink flow to the print head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If deaerated ink is used in conventional ink tanks, then initial filling characteristics improve, but dissolved oxygen increases over time causing discharging failures

Engineering Contradiction:
Improveinitial filling characteristicsVSAvoiddissolved oxygen concentration
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by adding specific surfactants (acetylenic glycol-based surfactant with HLB value of 3.5-4.5 and polyoxyethylene alkyl ether with HLB value of 10-16) and adjusting their concentrations within specific ranges. This parameter change enables the ink to maintain stability and prevent bubble formation even when exposed to atmospheric oxygen, resolving the contradiction between initial filling performance and long-term compositional stability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If open type ink tanks are used for easy refilling, then ease of operation improves, but air contact with ink causes bubble formation and discharging failures

Engineering Contradiction:
Improverefilling convenienceVSAvoiddischarging stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces surfactants as intermediary substances that mediate between the ink and atmospheric oxygen. These surfactants form protective interfaces that prevent oxygen from dissolving into the ink and forming bubbles, thereby enabling open-type ink tanks to maintain discharging stability while preserving refilling convenience.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By changing the surface tension parameters of the ink through surfactant addition, the patent enables the ink to resist bubble formation at the air-liquid interface. This parameter change allows open-type tanks to operate reliably without compromising discharging stability.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If air introducing ports are provided for ink supply, then ink flow stability improves, but bubbles are introduced into the ink tank causing filling failures

Engineering Contradiction:
Improveink flow stabilityVSAvoidfilling characteristics
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent converts the potentially harmful effect of air introduction into a beneficial one by using the introduced oxygen to form stable surfactant layers at the air-liquid interface. These layers prevent further oxygen dissolution and bubble formation, thereby maintaining ink flow stability while preventing filling failures.

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

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 initial filling characteristics and continuous printing stability by preventing bubble formation and ensuring effective ink flow, even in systems where the atmosphere contacts the ink, thereby enhancing the reliability of ink jet recording.

Implementation Method 1

an ink supply system featuring a filter in the ink supply path, which captures bubbles and ensures stable ink flow to the print head

Methodology Applied
Scientific EffectBubble capture and removal: Filter (physical)

Implementation Method 2

An ink composition containing an alkylene oxide adduct of acetylenic glycol with a main chain of 12 or more carbon atoms, acetylenic glycol with a main chain of 10 or more carbon atoms, and polyoxyalkylene alkyl ether

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentEP2843010B1Ink composition for ink-jet recording, ink supply system, and ink-jet recording device
Publication Date: 2018.12.19 SEIKO EPSON CORP
  • EP2843010B1 patent drawingFigure 1~2
  • EP2843010B1 patent drawingFigure 3
  • EP2843010B1 patent drawing

AI summary

There is provided an ink composition which has excellent initial filling characteristics and continuous printing stability even in a case of an ink composition (for example, dissolved nitrogen is equal to or greater than 5 ppm) which is almost not deaerated or an ink composition (for example, dissolved nitrogen is equal to or greater than 7 ppm) which is not deaerated at all. The ink composition includes an alkylene oxide adduct (A) of acetylenic glycol in which a main chain has 12 or more carbon atoms, acetylenic glycol (B) in which a main chain has 10 or more carbon atoms, and polyoxyalkylene alkyl ether (C).