Liquid Ejecting Head Ground Separation Against Static Damage

Solution Overview

Problem

Static electricity transmitted to the ejection surface of a liquid ejecting head can potentially damage the integrated circuit due to direct electrical coupling between the head cover and the wiring substrate, posing a risk of circuit failure.

Innovation Solution

The liquid ejecting head incorporates a conductive head cover and a wiring substrate with separate ground wirings, where the first ground wiring is coupled to the head cover and the second ground wiring is coupled to the integrated circuit, ensuring electrical separation between them, and a generation circuit provides a reference potential through one of these ground wirings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the wiring substrate is electrically coupled to the head cover through a single ground wiring, then the structure is simple, but static electricity can damage the integrated circuit

Engineering Contradiction:

Improveground wiring structureVSAvoidintegrated circuit protection

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The ground wiring is divided into two separate wirings: a first ground wiring that is electrically coupled to the head cover, and a second ground wiring that is electrically coupled to the integrated circuit. These two ground wirings are electrically separated from each other, creating independent grounding paths that prevent static electricity from the head cover from reaching and damaging the integrated circuit, while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the first ground wiring and second ground wiring are electrically separated, then the integrated circuit is protected from static electricity, but the device complexity increases

Engineering Contradiction:

Improveintegrated circuit protectionVSAvoidwiring substrate structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The ground wiring is divided into two separate wirings: a first ground wiring that is electrically coupled to the head cover, and a second ground wiring that is electrically coupled to the integrated circuit. These two ground wirings are electrically separated from each other, creating independent grounding paths that prevent static electricity from the head cover from reaching and damaging the integrated circuit, while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If a single ground connection is used, then the manufacturing process is simple, but static electricity transmission to the integrated circuit cannot be prevented

Engineering Contradiction:

Improveground wiring fabricationVSAvoidstatic electricity damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The ground wiring is divided into two separate wirings: a first ground wiring that is electrically coupled to the head cover, and a second ground wiring that is electrically coupled to the integrated circuit. These two ground wirings are electrically separated from each other, creating independent grounding paths that prevent static electricity from the head cover from reaching and damaging the integrated circuit, while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250367929A1Liquid ejecting head and liquid ejecting apparatus

Publication Date: 2025.12.04 SEIKO EPSON CORP

AI summary

A liquid ejecting head includes a liquid ejecting section including a plurality of drive elements for causing a plurality of nozzles to eject the liquid, a conductive head cover for exposing the plurality of nozzles to an outside, and a wiring substrate on which an integrated circuit is mounted, in which the wiring substrate includes a first ground wiring that is electrically coupled to the head cover without being electrically coupled to an electrode of the drive element and a second ground wiring that is electrically coupled to the integrated circuit, and the first ground wiring and the second ground wiring are electrically separated from each other in the wiring substrate.