Print Head State Determination via Composite Residual Vibration Signals

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Solution Overview

Problem

Existing liquid ejection apparatuses lack a method to effectively determine the ejection state of liquid from a nozzle in configurations with multiple pressure chambers driven by piezoelectric elements.

Innovation Solution

A method involving a first and second pressure chamber, each with a piezoelectric element generating residual vibration signals, which are combined and converted into a digital composite wave signal to determine the state of the print head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple pressure chambers are used to eject liquid from a single nozzle, then the amount of liquid ejected and the ability to handle high viscosity liquids is improved, but the complexity of determining the ejection state worsens

Engineering Contradiction:

Improveamount of liquid ejectedVSAvoidcomplexity of determining ejection state

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent combines the residual vibration signals from multiple piezoelectric elements into a single composite signal for state determination. Instead of analyzing each signal separately, the system merges them into one comprehensive indicator that reflects the overall ejection state, thereby simplifying the determination process while maintaining accuracy for multi-chamber configurations

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite signal serves multiple functions: it indicates ejection state, reflects liquid viscosity effects, and monitors system performance across all pressure chambers simultaneously. This universal indicator replaces the need for separate analysis of individual chamber signals, making the determination system adaptable to various multi-chamber configurations

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple piezoelectric elements drive a single nozzle, then the ejection performance for high viscosity liquids is improved, but the measurement precision of ejection state deteriorates

Engineering Contradiction:

Improveejection performance for high viscosity liquidsVSAvoidprecision of ejection state determination

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By merging the residual vibration signals from multiple piezoelectric elements into a composite signal, the system achieves more reliable ejection state determination. The composite signal integrates information from all driving elements, providing a more accurate and precise measurement of the overall ejection performance than individual signals could provide alone

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If residual vibration signals from multiple piezoelectric elements are combined, then the determination accuracy of ejection state is improved, but the signal processing complexity increases

Engineering Contradiction:

Improvedetermination accuracy of ejection stateVSAvoidsignal processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple residual vibration signals into a single composite signal through straightforward signal addition or superposition. This merging process improves determination accuracy by integrating information from all piezoelectric elements while maintaining relatively simple processing logic that avoids complex algorithms or multiple processing stages

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

Enables accurate determination of the ejection state of the liquid, improving the reliability and efficiency of the liquid ejection process.

Implementation Method 1

a first piezoelectric element configured to output a first residual vibration signal according to a first residual vibration generated in accordance with a volume change of the first pressure chamber, and a second piezoelectric element configured to output a second residual vibration signal according to a second residual vibration generated in accordance with a volume change of the second pressure chamber

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS20250162309A1Method of determining state of print head, head unit, and liquid ejection apparatus

Publication Date: 2025.05.22 SEIKO EPSON CORP

AI summary

A method of determining a state of a print head including a first pressure chamber and a second pressure chamber volumes of which vary in accordance with a drive signal, a nozzle which is communicated with the first pressure chamber and the second pressure chamber, and ejects a liquid, a first piezoelectric element configured to output a first residual vibration signal, and a second piezoelectric element configured to output a second residual vibration signal, includes a residual vibration generation step of generate a first residual vibration and a second residual vibration, a signal conversion step of converting a composite signal obtained by combining a first residual vibration signal and a second residual vibration signal with each other into a digital composite wave signal, and a determination step of determining the state of the print head based on the digital composite wave signal.