Inkjet Piezoelectric Ink Sediment Detection

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Solution Overview

Problem

Existing liquid ejection apparatuses, such as ink jet printers, cannot accurately determine whether pigment sedimentation occurs in the ink, leading to unnecessary flushing processes and ink consumption, as they cannot differentiate between ink thickening and pigment sedimentation.

Innovation Solution

Incorporating a piezoelectric element and a residual vibration detection unit that generates and detects a residual vibration waveform, allowing for the determination of pigment sedimentation by analyzing the waveform's cycle and amplitude, enabling selective flushing or stirring processes based on the sedimentation state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flushing process is performed to recover ejection function, then ejection abnormality is resolved, but ink consumption increases unnecessarily

Engineering Contradiction:

Improveejection functionVSAvoidink consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention changes the detection parameter from general ejection state to specific pigment sedimentation state by analyzing the cycle period of residual vibration waveform. This allows distinguishing between ink thickening (normal aging) and pigment sedimentation (abnormal state requiring flushing), enabling selective flushing only when necessary, thus reducing unnecessary ink consumption while maintaining ejection function reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical flushing operation with a detection-based decision system. By using the piezoelectric element to detect vibration characteristics and determine pigment sedimentation state, the system substitutes blind mechanical flushing with intelligent, condition-based recovery actions, minimizing unnecessary ink waste

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If pigment sedimentation is not detected, then ejection process continues, but image quality deteriorates due to uneven component distribution

Engineering Contradiction:

Improveejection continuityVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention implements a feedback mechanism where the piezoelectric element continuously monitors the cycle period of residual vibration waveform during ejection operations. When pigment sedimentation is detected (cycle period outside predetermined range), the system provides feedback to trigger recovery processes, ensuring image quality is maintained while allowing continuous ejection during normal conditions

Inventive Principle:

Principle #23Feedback

3Measurement precision

If residual vibration detection is implemented, then pigment sedimentation can be determined, but device complexity increases

Engineering Contradiction:

Improvesedimentation detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention makes the piezoelectric element multi-functional by using it both for ink ejection (applying voltage to generate pressure waves) and for detection (measuring residual vibration waveform cycle period). This eliminates the need for separate detection hardware, reducing device complexity while maintaining high measurement precision for pigment sedimentation detection

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach allows for precise determination of pigment sedimentation, minimizing unnecessary ink consumption by performing flushing only when required and using stirring for slight sedimentation, thereby optimizing the ejection process and reducing ink waste.

Implementation Method 1

a piezoelectric element provided in the pressure chamber; a driving signal generation unit that generates a driving signal which allows the piezoelectric element to be displaced such that the pressure chamber expands or is contracted

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a residual vibration detection unit that detects a cycle of a residual vibration waveform of the piezoelectric element which is generated by the driving signal being applied to the piezoelectric element and which indicates a value according to change of pressure in the pressure chamber

Methodology Applied

Scientific EffectResidual vibration: Vibration

Data Source

PatentUS9221253B2Liquid ejection apparatus

Publication Date: 2015.12.29 SEIKO EPSON CORP

AI summary

An ink jet printer includes an ejection unit including a nozzle which ejects a liquid containing a pigment; a cavity which communicates with the nozzle; and a piezoelectric element which is provided in the cavity, and a driving signal generation unit which generates a driving signal allowing the piezoelectric element to be displaced such that the cavity expands or is contracted. The ink jet printer includes a detection unit that detects a cycle of a residual vibration waveform of the piezoelectric element which is generated by the driving signal being applied to the piezoelectric element and indicates a value according to change of the pressure inside of the cavity and a determination unit that determines the pigment is settled based on the cycle of the residual vibration waveform detected by the detection unit.