Ink Jet Nozzle Meniscus Stabilization via Agitation Pulses

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Solution Overview

Problem

Pressure fluctuations in ink jet printing systems lead to degraded image quality due to unstable droplet formation and nozzle wetting, as existing methods struggle to maintain constant ink pressure amidst varying nozzle consumption.

Innovation Solution

Applying sub-threshold agitation pulses to nozzles that stop printing to stabilize the meniscus by replacing ink and reducing surfactant concentration, mitigating pressure fluctuations and maintaining ink stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a common ink supply passage is used to supply liquid ink to multiple nozzles, then the device complexity is reduced, but pressure fluctuations occur at the nozzles leading to degraded print quality

Engineering Contradiction:
Improveink supply system complexityVSAvoidprint quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system performs preliminary detection of the printing situation to identify when multiple nozzles stop printing simultaneously. Based on this detection, agitation pulses are applied in advance to the meniscus of affected nozzles to prevent pressure fluctuations and nozzle wetting before they can degrade print quality. This proactive approach maintains print quality without requiring complex individual pressure regulation for each nozzle.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the ink supply system is designed to maintain constant pressure at nozzles, then print quality is improved, but the system cannot respond to transient states when multiple nozzles stop printing simultaneously

Engineering Contradiction:
Improveprint qualityVSAvoidresponse to transient printing states
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the agitation pulse application based on real-time detection of printing conditions. When the detection unit identifies that a plurality of nozzles have stopped printing simultaneously, the control unit activates agitation pulses for the affected nozzles. This dynamic response allows the system to adapt to transient states while maintaining overall pressure stability, preventing the harmful effects of pressure fluctuations during these transient periods.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If agitation pulses are applied to nozzles that stop printing, then pressure fluctuations are suppressed and meniscus stability is improved, but additional control complexity is introduced

Engineering Contradiction:
Improvemeniscus stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system uses the existing actuators associated with each nozzle to generate agitation pulses, making the nozzles self-regulating. When a nozzle's meniscus becomes unstable due to pressure fluctuations from multiple nozzles stopping simultaneously, the same actuator that controls droplet ejection is used to apply agitation pulses that restore meniscus stability. This approach maintains meniscus stability without requiring additional dedicated components for each nozzle.

Inventive Principle:
Principle #25Self-service

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 method effectively suppresses the negative effects of pressure fluctuations, improving print quality by maintaining stable meniscus shape and surface tension, even during transient states of nozzle inactivity.

Implementation Method 1

activating at least one actuator associated with one of the nozzles that stop printing with sub-threshold agitation pulses which cause an agitation of a meniscus in the nozzle

Methodology Applied
Scientific EffectMeniscus agitation: Vibration

Implementation Method 2

replacing some of the ink that forms this meniscus will at least temporarily reduce the concentration of surfactants and will thereby stabilize the meniscus against the pressure fluctuations

Methodology Applied
Scientific EffectSurface tension stabilization: Surface Tension

Data Source

PatentEP3415322B1Method of ink jet printing
Publication Date: 2020.04.15 CANON PRODN PRINTING HLDG BV
  • EP3415322B1 patent drawingFigure 1
  • EP3415322B1 patent drawingFigure 2
  • EP3415322B1 patent drawingFigure 3

AI summary

A method of ink jet printing, wherein liquid ink is supplied to a plurality of nozzles (26) via a common ink supply passage (22), and actuators (32) associated with the nozzles (26) are controlled to cause ink droplets to be expelled from the nozzles (26) in accordance with image information (46, 48) to be printed, characterized by the steps of: - detecting a situation where a number of the nozzles (26) which are connected to the common ink supply passage (22) and are presently active but stop printing within a given time interval is larger than a given maximum number; - if that situation is detected, activating at least one actuator (32) associated with one of the nozzles (26) that stop printing with sub-threshold agitation pulses which cause an agitation of a meniscus (34) in the nozzle (26) without a droplet being expelled.