Liquid Discharge Head Bonding Recess Design for Adhesive Curing

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Solution Overview

Problem

The existing liquid discharge head bonding process faces issues with adhesive squeeze-out and insufficient curing due to the design of recesses in the bonding faces, leading to temporary bonding strength variations.

Innovation Solution

The introduction of a recess configuration with a first recess and a second recess extending in an inclined direction to guide ultraviolet light and prevent adhesive squeeze-out, ensuring uniform curing and enhanced bonding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a recess is formed in the bonding face to apply adhesive, then adhesive application is facilitated, but adhesive squeeze-out occurs and curing becomes insufficient

Engineering Contradiction:

Improveadhesive applicationVSAvoidbonding strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The recess is divided into two distinct parts: a first recess for adhesive application and a second recess for light transmission. This segmentation allows each part to fulfill its specific function independently, preventing the adhesive from being exposed to light while ensuring proper curing in the bonding area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second recess acts as an intermediary structure that guides ultraviolet light from the outer peripheral end to the inner side face of the first recess. This intermediary passage enables light to reach the adhesive without directly exposing the adhesive application area, solving the contradiction between ease of application and curing reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the recess is open to the outer peripheral end, then adhesive application is easier, but ultraviolet light cannot reach the inner side face for curing

Engineering Contradiction:

Improveadhesive applicationVSAvoidcuring uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The recess is segmented into a first recess (for adhesive) and a second recess (for light transmission), allowing the adhesive application area to be separated from the light exposure path. This enables easy adhesive application while ensuring uniform curing through the second recess.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution transitions from a two-dimensional surface recess to a three-dimensional structured recess with multiple levels. The second recess extends from the outer peripheral end toward the inner side, creating a light pathway that penetrates depth-wise to reach the adhesive in the first recess, achieving uniform curing throughout.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If adhesive is applied in a recess, then bonding is facilitated, but adhesive squeeze-out reduces bonding reliability

Engineering Contradiction:

Improvebonding processVSAvoidbonding strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The recess is divided into a first recess for controlled adhesive application and a second recess that prevents squeeze-out by directing excess adhesive away from critical bonding areas. This segmentation maintains bonding reliability while facilitating the bonding process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second recess converts the potentially harmful adhesive squeeze-out into a beneficial light-guiding structure. By providing a dedicated passage for light transmission, the structure that could cause reliability issues instead becomes essential for achieving uniform curing and enhancing bonding strength.

Inventive Principle:

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

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 achieves 100% adhesive curing with zero squeeze-out, significantly improving the temporary bonding strength and reliability of the liquid discharge head components.

Implementation Method 1

the second recess includes a first wall face and a second wall face opposed to the first wall face. The first wall face and the second wall face define side walls of the second recess in a width direction orthogonal to the extending direction of the second recess. The extending direction of the second recess is inclined with respect to a perpendicular line perpendicular to the inner side face of the first recess.

Methodology Applied

Scientific EffectLight transmission and guidance: Light

Data Source

PatentUS12090759B2Liquid discharge head, liquid discharge apparatus, and bonded unit

Publication Date: 2024.09.17 RICOH CO LTD

AI summary

A liquid discharge head includes a first component having a bonding face having a recess and a second component bonded to the bonding face of the first component. The recess includes a first recess to which an adhesive is applied and a second recess extending in an extending direction to connect the first recess and an outer peripheral end of the first component. The first recess includes an inner side face that is an interior of the first component. The second recess includes a first wall face and a second wall face opposed to the first wall face. The first wall face and the second wall face define side walls of the second recess in a width direction orthogonal to the extending direction of the second recess. The extending direction is inclined with respect to a perpendicular line perpendicular to the inner side face of the first recess.