Liquid Discharge Head Bonding Structure for Nozzle Pitch Accuracy

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Solution Overview

Problem

Existing liquid discharge heads face issues with positional accuracy of nozzles due to deformation during metal diffusion bonding, leading to variations in nozzle pitch and reduced precision.

Innovation Solution

Implementing cylindrical connecting portions on the bonding surface of the housing to reduce the bonding area and minimize deformation, ensuring uniform pressure distribution during diffusion bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal diffusion bonding is used to bond multiple metal plates and housing, then bonding strength is improved, but deformation of metal plates increases leading to decreased nozzle positional accuracy

Engineering Contradiction:
Improvebonding strengthVSAvoidnozzle positional accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The bonding surface is divided into multiple discrete bonding regions (first bonding region, second bonding region, third bonding region) instead of a continuous large bonding area. This segmentation reduces the total bonding area and distributes the bonding pressure, thereby minimizing deformation of the metal plates while maintaining sufficient bonding strength through multiple localized bonds.

Inventive Principle:
Principle #1Segmentation

2Strength

If high pressure (1 MPa or more) is applied during diffusion bonding, then bonding strength is improved, but deformation of metal plates increases

Engineering Contradiction:
Improvebonding strengthVSAvoidmetal plate deformation
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

High bonding pressure is applied locally at specific bonding regions (first bonding region at the end surface, second bonding region at the side surface, third bonding region at another side surface) rather than uniformly across the entire bonding surface. This localized pressure application achieves strong bonding at critical interfaces while minimizing overall deformation of the metal plates.

Inventive Principle:
Principle #3Local quality

3Strength

If large bonding area is used for diffusion bonding, then bonding strength is improved, but deformation and thinning of metal plates increases

Engineering Contradiction:
Improvebonding strengthVSAvoidmetal plate thickness
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The bonding interface is segmented into multiple discrete bonding regions distributed across different surfaces (end surface, side surfaces) rather than a single large bonding area. This approach achieves comprehensive bonding coverage and strong overall bonding strength while minimizing the thickness reduction at any single location by distributing the bonding process across multiple localized regions.

Inventive Principle:
Principle #1Segmentation

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

Enhances the positional accuracy of nozzles by reducing deformation and maintaining consistent nozzle pitch, thereby improving the durability and reliability of the liquid discharge head.

Implementation Method 1

a housing (340) that supports the nozzle plate (303) and is bonded to the nozzle plate (303) by a step including diffusion bonding

Methodology Applied
Scientific EffectDiffusion bonding: Diffusion Welding

Data Source

PatentEP4434753B1Liquid discharge head, liquid discharge apparatus, and method for manufacturing liquid discharge head
Publication Date: 2026.02.18 RICOH CO LTD
  • EP4434753B1 patent drawingFigure 1
  • EP4434753B1 patent drawingFigure 2
  • EP4434753B1 patent drawingFigure 3

AI summary

A liquid discharge head includes: a nozzle plate (3, 303, 303a, 303b, 303c, 2303, 2303a, 2303b) having multiple nozzle holes from which a liquid is dischargeable, the multiple nozzle holes arrayed in a nozzle array direction; a housing (140, 340, 340a, 340b, 340c, 2340) bonded to the nozzle plate (3, 303, 303a, 303b, 303c, 2303, 2303a, 2303b) by a diffusion bonding to support the nozzle plate (3, 303, 303a, 303b, 303c, 2303, 2303a, 2303b); multiple connecting portions (310, 310a, 310b, 310c): and disposed on one of the nozzle plate (3, 303, 303a, 303b, 303c, 2303, 2303a, 2303b) or the housing (140, 340, 340a, 340b, 340c, 2340); contacting the nozzle plate and the housing (140, 340, 340a, 340b, 340c, 2340) to bond the nozzle plate (3, 303, 303a, 303b, 303c, 2303, 2303a, 2303b) and the housing (140, 340, 340a, 340b, 340c, 2340).