Piezoelectric Liquid Jet Head Electrode Placement

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Solution Overview

Problem

Existing liquid jet head technologies face complexity and increased man-hours due to the need for electrical division of electrodes on wall surfaces, and the oblique vapor deposition method is time-consuming as groove widths narrow, impacting productivity and recording density.

Innovation Solution

A liquid jet head design with a side wall between ejection and non-ejection channels, featuring individual and common electrodes positioned above and below a polarization boundary, respectively, allows for efficient displacement of the side wall to eject liquid droplets using an oblique vapor deposition method, reducing electrode material consumption and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If electrodes are formed on the entire wall surface of side walls using plating method, then electrode coverage is complete, but electrode material is deposited on bottom surfaces of grooves increasing material consumption and complexity

Engineering Contradiction:
Improveelectrode placement precisionVSAvoidelectrode material consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies local quality by positioning electrodes only on specific portions of the side walls (above and below the polarization boundary) rather than covering the entire wall surface. This selective electrode placement reduces material consumption while maintaining the necessary electrical fields for actuator operation, directly addressing the contradiction between complete coverage and material efficiency.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If oblique vapor deposition method is used to form electrodes on side walls, then electrode formation is simplified, but the method becomes time-consuming as groove widths narrow, reducing productivity

Engineering Contradiction:
Improveelectrode formation simplicityVSAvoidproduction speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent segments the electrode formation process by dividing the side wall into distinct regions (above and below the polarization boundary) and placing electrodes only in these specific segments. This segmentation allows for faster deposition methods compared to oblique vapor deposition, as the electrodes don't need to navigate narrow groove widths, thereby improving productivity while maintaining manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If polarization boundary is positioned at the center of side wall height, then symmetry is maintained, but electrode placement flexibility is reduced for optimizing ejection efficiency

Engineering Contradiction:
Improvestructural symmetryVSAvoidelectrode placement flexibility
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent deliberately introduces asymmetry by positioning the polarization boundary at a specific height (above the center) rather than at the midpoint of the side wall. This asymmetric positioning provides flexibility in electrode placement, allowing optimization of the electric field distribution for improved ejection efficiency, while still maintaining sufficient structural stability for actuator operation.

Inventive Principle:
Principle #4Asymmetry

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 design enhances ejection efficiency, reduces production costs, and maintains high recording density while simplifying the electrode formation process, even with narrower grooves, by leveraging the 'leaking electric field' effect and optimizing electrode placement.

Implementation Method 1

The side wall 3 is made of a piezoelectric material... When drive electrodes 119c and 119d of a jet channel 113a to be driven are subjected to a voltage, both side walls 117a and 117d of the jet channel 113a to be driven are subjected to thickness slip deformation

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

allows for efficient displacement of the side wall to eject liquid droplets using an oblique vapor deposition method

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentEP2915670B1Liquid jet head and liquid jet apparatus
Publication Date: 2019.07.31 SII PRINTEK INC
  • EP2915670B1 patent drawingFigure 1
  • EP2915670B1 patent drawingFigure 2A~2B
  • EP2915670B1 patent drawingFigure 3A~3B

AI summary

A liquid jet head includes a side wall installed between channels, and in which two piezoelectric materials having mutually different polarization directions are laminated in a height direction, interposing a polarization boundary, an upper member fixed to an upper end of the side wall and installed on an upper portion of the channel, a lower member fixed to a lower end of the side wall and installed on a lower portion of the channel, and an electrode installed on a wall surface of the side wall, wherein the polarization boundary is positioned above 1/2 the height of the side wall, and the electrode is installed from an upper end of the wall surface, to a vicinity of the polarization boundary, or below the polarization boundary and above a lower end of the wall surface.