Liquid Ejection Head with Segmented Piezoelectric Elements

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Solution Overview

Problem

Existing liquid ejection apparatuses, such as ink jet printers, face reduced determination accuracy due to electrical noise generated by switching piezoelectric elements used for both driving and detecting residual vibration waveforms, which affects the accuracy of ink state determination.

Innovation Solution

A liquid ejection head unit with separate energy generating elements for driving and detecting, allowing for simultaneous operation without the need to switch the piezoelectric elements, thereby minimizing electrical noise and improving determination accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same piezoelectric element is used for both driving and detecting residual vibration waveforms, then device complexity is reduced, but electrical noise generated by switching lowers determination accuracy

Engineering Contradiction:

Improvestructure complexityVSAvoiddetermination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The piezoelectric element is divided into two functionally independent parts: a drive piezoelectric element for generating pressure waves and a detect piezoelectric element for detecting residual vibration waveforms. This segmentation eliminates the need to switch the same element between driving and detecting modes, thereby preventing electrical noise from contaminating the detection signal and improving determination accuracy.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the same piezoelectric element is used for both driving and detecting, then the number of components is reduced, but electrical noise interferes with the residual vibration waveform

Engineering Contradiction:

Improvenumber of piezoelectric elementsVSAvoidelectrical noise interference

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The piezoelectric element is segmented into separate drive and detect elements. The drive piezoelectric element generates pressure waves without interfering with the detection circuit, while the detect piezoelectric element exclusively monitors residual vibration waveforms. This physical and functional separation eliminates electrical noise interference from switching operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The detection function is extracted from the drive piezoelectric element and assigned to a separate detect piezoelectric element. This extraction removes the source of electrical noise (switching operations) from the detection path, allowing clean detection of residual vibration waveforms for accurate determination of liquid ejection state.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If switching is required between driving and detecting states, then device structure is simplified, but determination accuracy of ejection state is lowered

Engineering Contradiction:

Improvecontrol operation complexityVSAvoidejection state determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The control system is segmented to independently control drive and detect piezoelectric elements. The drive circuit controls the drive element for liquid ejection, while the detection circuit monitors the detect element for residual vibration analysis. This segmentation eliminates the need for state switching and enables simultaneous or sequential operation without electrical noise contamination, improving ejection state determination accuracy.

Inventive Principle:

Principle #1Segmentation

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 configuration enhances the accuracy of determining the ejection state of the liquid by reducing noise interference and improving ejection efficiency, leading to better image quality and reliability.

Implementation Method 1

a piezoelectric element that apply pressure to the pressure chamber

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

detects a residual vibration waveform based on the vibration of ink after supplying a drive signal to the pressure element

Methodology Applied

Scientific EffectVibration detection: Vibration

Data Source

PatentUS11426998B2Liquid ejection head unit, liquid ejection apparatus, and liquid ejection state determination method of liquid ejection apparatus

Publication Date: 2022.08.30 SEIKO EPSON CORP

AI summary

A liquid ejection head unit includes a first energy generating element that generates energy that applies pressure to a liquid in the first pressure chamber; a second energy generating element that generates energy that applies pressure to a liquid in the second pressure chamber; a nozzle flow path which communicates the first pressure chamber and the second pressure chamber and in which a nozzle that ejects a liquid is provided; a drive circuit that drives the first energy generating element and the second energy generating element by applying a drive pulse; a detection circuit that detects a parameter related to a physical property of a liquid in the second pressure chamber; wherein a controller drives the first energy generating element by the drive circuit, and performs a first detection operation of detecting the parameter in the second pressure chamber by the detection circuit.