Liquid Ejecting Head with Split Piezo Elements for Higher Throughput

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Solution Overview

Problem

Existing liquid ejecting heads using a shared piezoelectric element for both liquid ejection and residual vibration detection face limitations in driving frequency and throughput due to real-time detection of residual vibrations, and the structure of separate piezoelectric elements for these functions is not sufficiently examined.

Innovation Solution

A liquid ejecting head with separate first and second piezoelectric elements, where the first element applies pressure for ejection and the second element detects residual vibration, with distinct neutral axes and differing thickness ratios of piezoelectric bodies and insulating layers to optimize performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single piezoelectric element is used for both liquid ejection and residual vibration detection, then device complexity is reduced, but driving frequency and throughput are limited due to real-time detection requirements

Engineering Contradiction:
Improvestructure complexityVSAvoidthroughput
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The piezoelectric element is divided into two functionally independent elements: a first piezoelectric element for liquid ejection and a second piezoelectric element for residual vibration detection. This segmentation allows simultaneous operation of ejection and detection functions without mutual interference, thereby increasing driving frequency and throughput while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Both the first and second piezoelectric elements are integrated into the same pressure chamber structure, allowing the pressure chamber to serve multiple functions: liquid ejection when the first element is activated and residual vibration detection when the second element is activated. This multi-functionality approach resolves the contradiction by enabling both functions within a unified structural framework

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

2Device complexity

If a single piezoelectric element is used for both liquid ejection and residual vibration detection, then manufacturing cost is reduced, but driving frequency is limited due to real-time detection requirements

Engineering Contradiction:
Improvestructure complexityVSAvoiddriving frequency
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The piezoelectric element is divided into two functionally independent elements: a first piezoelectric element for liquid ejection and a second piezoelectric element for residual vibration detection. This segmentation allows simultaneous operation of ejection and detection functions without mutual interference, thereby increasing driving frequency while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first piezoelectric element operates in periodic cycles for liquid ejection while the second piezoelectric element continuously monitors residual vibrations. This periodic action pattern allows the ejection function to operate at high frequency while the detection function runs continuously, resolving the contradiction between driving frequency and real-time detection requirements

Inventive Principle:
Principle #19Periodic action

3Productivity

If separate piezoelectric elements are used for liquid ejection and vibration detection, then driving frequency and throughput are improved, but the structure becomes more complex

Engineering Contradiction:
ImprovethroughputVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The first piezoelectric element for ejection and the second piezoelectric element for detection are merged into a single integrated pressure chamber structure. This merging allows both separate functions to operate simultaneously with improved throughput while minimizing structural complexity through unified design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure chamber is designed to serve multiple functions: liquid ejection when the first piezoelectric element is activated and residual vibration detection when the second element is activated. This multi-functionality approach allows separate piezoelectric elements to operate independently while maintaining a compact, low-complexity overall structure

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

4Productivity

If separate piezoelectric elements are used for liquid ejection and vibration detection, then throughput is improved, but manufacturing complexity increases

Engineering Contradiction:
ImprovethroughputVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The first piezoelectric element for ejection and the second piezoelectric element for detection are merged into a single integrated pressure chamber structure. This merging allows both separate functions to operate simultaneously with improved throughput while minimizing manufacturing complexity through unified design and assembly processes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure chamber is designed to serve multiple functions: liquid ejection when the first piezoelectric element is activated and residual vibration detection when the second element is activated. This multi-functionality approach simplifies manufacturing by reducing the number of separate components and assembly steps compared to completely separate systems

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

Enhances driving frequency and throughput by allowing independent operation of ejection and vibration detection, improving the overall efficiency and effectiveness of the liquid ejecting process.

Implementation Method 1

a first piezoelectric element, a pressure chamber that applies a pressure for ejecting a liquid from a nozzle when the first piezoelectric element is driven

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a second piezoelectric element, and a detection chamber in which the second piezoelectric element detects a residual vibration of the pressure applied in the pressure chamber

Methodology Applied
Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentEP4670978A1Liquid ejecting head
Publication Date: 2025.12.31 SEIKO EPSON CORP
  • EP4670978A1 patent drawingFigure 1
  • EP4670978A1 patent drawingFigure 2
  • EP4670978A1 patent drawingFigure 3

AI summary

A liquid ejecting head includes a pressure chamber that applies a pressure of a liquid for ejecting a liquid from a nozzle when a first piezoelectric element is driven, and a detection chamber in which a second piezoelectric element detects a residual vibration of the pressure of the liquid applied in the pressure chamber. The first piezoelectric element includes a first piezoelectric body, a first upper electrode, a first lower electrode, and a first vibration plate provided below the first lower electrode, the second piezoelectric element includes a second piezoelectric body, a second upper electrode, a second lower electrode, and a second vibration plate provided below the second lower electrode, and a neutral axis of the second piezoelectric element is positioned below a neutral axis of the first piezoelectric element.