Segmented Piezoelectric Actuator Structure for Liquid Ejection Heads

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Solution Overview

Problem

Piezoelectric actuators used in liquid ejection apparatuses, such as inkjet printer heads, are brittle and have a fine shape, making them difficult to mount easily.

Innovation Solution

A liquid ejection head design featuring a first actuator structure with separate first actuator elements and electrodes, connected by a flexible circuit through an anisotropic conductive film or solder, and a substrate arrangement that facilitates easier mounting and electrical connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If piezoelectric elements are divided into fine columnar shapes with grooves, then actuator performance is improved, but ease of mounting deteriorates due to brittleness and fine shape

Engineering Contradiction:
Improveactuator performanceVSAvoidease of mounting
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The piezoelectric body is divided into multiple columnar piezoelectric elements by forming grooves, which segment the structure to improve actuator performance while the external electrodes are configured to facilitate mounting of these segmented elements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A resin layer is introduced as an intermediary material between the piezoelectric elements and the support structure, providing a bonding interface that accommodates the fine columnar shape and brittleness of the piezoelectric elements while enabling secure mounting

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If external electrodes are individually separated on one side of piezoelectric body, then electrical control precision is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical control precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

External electrodes are segmented into individual electrodes on one side of the piezoelectric body to enable precise electrical control of each piezoelectric element, while the other side maintains a common electrode structure to simplify connections

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different electrode configurations are applied to different sides of the piezoelectric body: individual electrodes on one side for precise control and common electrodes on the other side for simplified wiring, creating local optimization of electrical connections

Inventive Principle:
Principle #3Local quality

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

Improves ease of mounting and electrical connectivity for piezoelectric actuators, enhancing the reliability and efficiency of liquid ejection processes.

Implementation Method 1

connected to the first electrodes by an anisotropic conductive film (ACF)

Methodology Applied
Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

A piezoelectric actuator using a piezoelectric body such as lead-zirconate-titanate (PZT) is used as a drive source

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4624163A1Liquid ejection head and liquid ejection apparatus
Publication Date: 2025.10.01 RISO TECH CORP
  • EP4624163A1 patent drawingFigure 1
  • EP4624163A1 patent drawingFigure 2
  • EP4624163A1 patent drawingFigure 3~4

AI summary

A liquid ejection head includes a nozzle plate including nozzles arranged in a first direction, pressure chambers arranged along the first direction and capable of storing liquid, each pressure chamber communicating with one of the nozzles, a structure including a first base portion continuously extending along the first direction and first actuator elements separate from each other, each actuator element extending from the first base portion to one of the pressure chambers, first electrodes separate from each other, each first electrode extending from one side surface of the base portion to one side surface of one of the actuator elements, and a first driving circuit connected to each of the first electrodes on said one side surface of the first base portion and configured to output signals for actuating the first actuator elements to the first electrodes.