Liquid Discharge Head Release Grooves for Adhesive Containment

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Solution Overview

Problem

The issue of adhesive overflow and processing failure in liquid discharge heads due to inadequate release grooves between bonded plates, particularly between the cavity plate and piezoelectric actuator substrate, leading to potential adhesive entry into the pressurizing chamber.

Innovation Solution

Incorporation of a release groove system on the cavity plate surface and through-holes connecting to the exterior, ensuring effective discharge of excess adhesive during bonding, preventing overflow and maintaining chamber integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a release groove is formed along the outer peripheral part of the plate to prevent adhesive overflow, then adhesive containment is improved, but the release groove may still allow adhesive to enter the pressurizing chamber through gaps or insufficient coverage

Engineering Contradiction:

Improveadhesive containmentVSAvoidchamber integrity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The release groove is segmented into multiple sections: a first release groove surrounding the piezoelectric actuator substrate, a second release groove surrounding the cavity groups, and a third release groove connecting to the exterior. This segmentation ensures comprehensive adhesive containment while maintaining chamber integrity through multiple barrier layers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cavity plate acts as an intermediary structure between the bonding process and the pressurizing chamber. By incorporating release grooves within the cavity plate structure, excess adhesive is captured and redirected before it can compromise the chamber integrity, serving as a protective mediator.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the cavity plate and piezoelectric actuator substrate are bonded together to form a functional liquid discharge head, then device functionality is improved, but adhesive overflow during bonding can cause processing failure

Engineering Contradiction:

Improvedevice functionalityVSAvoidprocessing success

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The release groove structure is pre-formed in the cavity plate before the bonding process. This preliminary preparation ensures that when adhesive is applied during bonding, any excess adhesive is automatically contained and redirected through the pre-designed groove pathways, preventing processing failures while maintaining device functionality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The potential harm of adhesive overflow is converted into a beneficial feature by designing the release groove to actively channel excess adhesive away from critical areas. The adhesive that would otherwise cause processing failure is instead redirected through the groove system to exit ports, turning a potential defect into a controlled process feature.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If multiple cavity groups are arranged on the cavity plate to increase discharge capacity, then productivity is improved, but the complexity of ensuring proper adhesive release and containment increases

Engineering Contradiction:

Improvedischarge capacityVSAvoidadhesive management

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The cavity plate design provides universal adhesive management functionality that serves all cavity groups simultaneously. The first and second release grooves create a unified adhesive containment system that protects multiple cavity groups and piezoelectric actuator substrates with a single integrated structure, rather than requiring separate adhesive management for each cavity group.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Prevents adhesive overflow, reduces processing failures, and maintains the functionality and reliability of the liquid discharge head by ensuring clean bonding between the cavity plate and piezoelectric actuator substrate.

Implementation Method 1

a piezoelectric actuator substrate configured to change a volume of the pressurizing chamber and discharge liquid from the nozzle

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4082798B1Liquid discharge head and recording device

Publication Date: 2025.10.22 KYOCERA CORP

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AI summary

A liquid discharge head includes a base plate, a cavity plate located on the base plate and including a cavity, and a piezoelectric actuator substrate located on the cavity plate. The cavity plate includes: a first groove located inside a contact region with the piezoelectric actuator substrate and configured to release an adhesive for bonding the cavity plate and the piezoelectric actuator substrate; and a second groove located in a manner to surround the contact region with the piezoelectric actuator substrate and configured to release the adhesive. The base plate includes a third groove configured to open the first groove to the atmosphere. The third groove is configured to communicate between the first groove and the outside through a first hole communicating with the first groove and a second hole located outside the contact region of the cavity plate and the piezoelectric actuator substrate.