Annular Conductor for Liquid Potential Stability in Piezoelectric Ejectors

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Solution Overview

Problem

Existing liquid ejecting devices face challenges in maintaining the potential of the liquid at a constant level without increasing the device size, as electrical charges can cause short circuits and instability in ink droplet direction.

Innovation Solution

An annular conductor is placed on the piezoelectric actuator to surround the through-hole, keeping the liquid supply member bonded via this conductor, ensuring the liquid's potential equals the constant potential, thus maintaining stability without additional structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a structure is added to maintain liquid potential at a constant level, then the potential stability is improved, but the device size increases

Engineering Contradiction:
Improveliquid potential stabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The annular conductor is integrated into the existing piezoelectric actuator structure, serving dual functions: as an electrical component for potential control and as part of the liquid supply pathway. This eliminates the need for separate potential control structures, maintaining liquid potential stability without increasing device size.

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

Solution Approach 2:

The invention combines the potential control function with the existing through-hole structure by forming an annular conductor around the through-hole. The liquid supply member is bonded via this annular conductor, merging the electrical potential control function with the liquid delivery pathway into a single integrated structure.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the liquid is electrically charged, then the potential difference may cause short circuit, but adding potential control structures increases device complexity

Engineering Contradiction:
Improveshort circuit preventionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The annular conductor serves multiple functions simultaneously: it controls liquid potential to prevent short circuits, provides bonding for the liquid supply member, and maintains structural integrity. This multi-functionality prevents short circuits without adding complex separate structures.

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

3Reliability

If the liquid potential becomes unstable, then ink droplet direction control is improved, but additional potential control structures are required

Engineering Contradiction:
Improveink droplet direction stabilityVSAvoidcontrol structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The potential control function is merged with the liquid supply structure through the annular conductor. As liquid flows through the through-hole surrounded by the annular conductor, its potential is stabilized without requiring separate control mechanisms, ensuring stable ink droplet direction while avoiding additional structural complexity.

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

This configuration maintains the liquid's potential at a constant level without enlarging the device, preventing short circuits and ensuring stable ink droplet direction, enhancing the reliability and efficiency of the liquid ejecting process.

Implementation Method 1

a piezoelectric layer, and an upper electrode layer... One piezoelectric element is constituted by the lower electrode layer, the piezoelectric layer, and the upper electrode layer for giving a pressure to ink in a corresponding one of the pressure chambers

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3147122B1Liquid ejecting device
Publication Date: 2020.07.08 BROTHER KOGYO KK
  • EP3147122B1 patent drawingFigure 1
  • EP3147122B1 patent drawingFigure 2
  • EP3147122B1 patent drawingFigure 3

AI summary

A liquid ejecting device (16), including: a flow-path defining member (21) having a pressure chamber (26) formed therein; a piezoelectric actuator (22) constituted by a plurality of layers (22, 32, 37, 40, 41; 72, 75) which includes a piezoelectric layer (37), a common electrode (32; 72), and an individual electrode (34; 74), superposed on the flow-path defining member, and having a through-hole (29) communicating with the pressure chamber; an annular conductor (45) disposed on one of opposite surfaces of the piezoelectric actuator remote from the flow-path defining member such that a part (40, 41; 75) of the layers are sandwiched between the annular conductor and the common electrode, the annular conductor surrounding a periphery of the through-hole; and a liquid supply member (23) having a supply path (64) communicating with the through-hole and bonded to the one of the opposite surfaces via the annular conductor, wherein the annular conductor is connected to a terminal (47) configured to be given a predetermined constant potential and is exposed to a flow path defmed by the through-hole.