Liquid Ejecting Head Wiring Substrate Positioning

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Solution Overview

Problem

Existing liquid ejecting apparatuses face issues with deformation of flow paths due to the pressing load of wiring substrates, which affects ink flow and printing quality, particularly in inkjet printing systems where viscosity changes and sedimentation occur, leading to pressure variations and potential deformation of the shared flow path shape.

Innovation Solution

The design incorporates a wiring substrate that is electrically coupled to the piezoelectric element through a lead electrode, with the coupling portion overlapping with the flow path area of individual recovery paths, allowing the pressing load to be received by partition walls, thereby minimizing deformation of the flow path shape and ensuring secure electrical coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wiring substrate is mounted on the flow path formation substrate, then electrical coupling is achieved, but the pressing load deforms the flow path shape

Engineering Contradiction:
Improveelectrical couplingVSAvoidflow path shape
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The flow path area is divided into multiple individual recovery paths, each with its own partition walls. The wiring substrate is positioned to overlap with these partition walls rather than the center of the flow path area, distributing the pressing load across multiple structural supports and preventing deformation of any single flow path shape.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the wiring substrate is positioned over the flow path area, then electrical coupling is simplified, but ink flow is affected by deformation

Engineering Contradiction:
Improveelectrical couplingVSAvoidink flow
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The wiring substrate is strategically positioned to overlap with specific regions (partition walls) within the flow path area that have higher structural support. This local positioning allows electrical coupling to be achieved while the pressing load is concentrated on rigid partition walls rather than being distributed across the entire flow path area, thus maintaining ink flow reliability.

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

This configuration effectively suppresses deformation of the flow path shape, enhances ink ejection stability, and improves the quality of printed matter by maintaining the integrity of the flow paths and reducing the impact of ink ejection pressure variations.

Implementation Method 1

a piezoelectric element (44) per nozzle (N), which causes pressure variations in the liquid

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3587116B1Liquid ejecting head, liquid ejecting apparatus, and manufacturing method thereof
Publication Date: 2023.10.18 SEIKO EPSON CORP
  • EP3587116B1 patent drawingFigure 1
  • EP3587116B1 patent drawingFigure 2A
  • EP3587116B1 patent drawingFigure 2B

AI summary

A flow path formation substrate to which a nozzle plate having a plurality of nozzles is mounted includes a shared supply path shared in liquid supply to a nozzle, an individual supply path branching off from the shared supply path and leading to a pressure chamber per nozzle, an individual recovery path including a communication flow path per nozzle, through which the nozzle and the pressure chamber communicate with each other, and a shared recovery path into which a plurality of individual recovery paths merge and which is shared in liquid recovery from the nozzles. A conduction unit electrically coupled through a lead electrode to a pressure generator causing a pressure of the pressure chamber to vary is located at a position where the conduction unit overlaps with a flow path area of at least one individual flow path of the individual supply path or the individual recovery path in a plan view from a lamination direction in which the nozzle plate and the flow path formation substrate are laminated.