Inkjet Head Vibration Analysis for Clog Detection

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Solution Overview

Problem

Current liquid droplet ejecting apparatuses, such as inkjet printers, face challenges in accurately determining the ejection state of liquid droplets and the necessity for replacing the droplet ejecting head due to issues like clogging and ink thickening, which leads to inefficient ink consumption and incomplete printing.

Innovation Solution

A liquid droplet ejecting apparatus equipped with an ejection abnormality detecting section that analyzes residual vibration patterns of the vibration plate within the droplet chamber, combined with a maintenance unit for cleaning and a remote monitoring system, to assess the ejection state and determine the need for head replacement based on detected abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cleaning mechanism is repeatedly performed on clogged nozzle, then cleaning operation continues, but ink is uselessly consumed and clogging is not recovered

Engineering Contradiction:
Improvenozzle discharging functionVSAvoidink consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The system performs preliminary inspection of the nozzle's discharging state using vibration detection before executing cleaning operations. By detecting residual vibrations of the liquid chamber through the piezoelectric element, the system identifies nozzles that require cleaning in advance, preventing unnecessary ink consumption on already severely clogged nozzles that cannot be recovered by cleaning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the discharging state of nozzles by detecting vibration characteristics and provides feedback on the actual condition. This feedback mechanism allows the system to adjust cleaning operations based on real-time nozzle status, stopping cleaning when no further improvement is possible and preventing wasteful ink consumption.

Inventive Principle:
Principle #23Feedback

2Loss of substance

If inspection is performed only by detecting residual vibration of liquid chamber, then ink consumption is reduced, but accuracy of determining ejection state and replacement necessity is insufficient

Engineering Contradiction:
Improveink consumptionVSAvoidejection state detection accuracy
Core Design Contradiction:
Loss of substanceVSMeasurement precision

Solution Approach 1:

The system merges multiple detection methods: vibration detection (acoustic signal from liquid chamber), optical detection (imaging the ejection state of liquid droplets), and analysis of both internal (liquid chamber) and external (droplet trajectory) characteristics. This combination provides comprehensive and accurate determination of nozzle discharging state and replacement necessity without requiring actual ink ejection for testing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses an intermediary imaging device to capture optical information about the ejection state without requiring the nozzle to actually eject ink during inspection. The imaging device acts as a mediator that translates the ejection state into detectable optical signals, enabling accurate assessment without ink consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of substance

If cleaning operation is performed without accurate detection, then cleaning may be executed unnecessarily, but accurate detection requires complex monitoring system

Engineering Contradiction:
Improveink consumptionVSAvoidmonitoring system complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The piezoelectric element serves multiple functions: it acts as both the actuator for ejecting liquid droplets and the sensor for detecting residual vibrations of the liquid chamber. This multi-functionality eliminates the need for separate inspection mechanisms, reducing system complexity while enabling accurate detection of nozzle discharging state without ink consumption.

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

Solution Approach 2:

The liquid chamber and piezoelectric element perform self-inspection through their inherent vibration characteristics during normal operation. The system leverages the natural residual vibrations that occur during droplet ejection to monitor nozzle health, eliminating the need for dedicated inspection hardware and reducing overall system complexity.

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

This solution allows for accurate determination of the ejection state and timely replacement of the droplet ejecting head, reducing ink consumption and ensuring consistent printing quality by identifying and addressing issues like clogging and ink thickening.

Implementation Method 1

a piezoelectric element that changes a capacity of a liquid chamber storing ink

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an ejection abnormality detecting section that analyzes residual vibration patterns of the vibration plate within the droplet chamber

Methodology Applied
Scientific EffectVibration analysis: Vibration

Data Source

PatentEP3369575B1Liquid droplet ejecting apparatus, remote monitoring system, and method of determining replacement necessity of liquid droplet ejecting head
Publication Date: 2021.03.10 SEIKO EPSON CORP
  • EP3369575B1 patent drawingFigure 1
  • EP3369575B1 patent drawingFigure 2
  • EP3369575B1 patent drawingFigure 3

AI summary

A liquid droplet ejecting apparatus includes a liquid droplet ejecting head that includes a plurality of nozzles from which a liquid supplied from a liquid supply source through a liquid supply path is ejected as a liquid droplet, and ejects the liquid droplet from the nozzle to a recording medium to perform a recording process, a first detecting section that detects a vibration waveform of the pressure chamber, which is vibrated when an actuator is driven to cause the pressure chamber communicating with the nozzle to vibrate, to detect a state inside the pressure chamber, and a second detecting section that reads a pattern formed on the recording medium by ejecting the liquid droplet from the nozzle to detect an ejection state of the liquid droplet.