Liquid Ejection Head Tank Sealing Without Screw Fasteners

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Solution Overview

Problem

The use of screws or similar fasteners to fix the sub-tank member to the main body of a liquid ejection head increases the time and cost of fixing work and may lead to uneven contact pressure and reduced sealing reliability due to dimensional errors and increased number of parts.

Innovation Solution

A liquid ejection head design with a main body and tank configuration that uses sealing members interposed between non-parallel connecting portions, allowing for a simpler and more reliable connection through fitting engagement of protrusions and recesses, reducing the need for screws.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If screws or similar fasteners are used to fix the sub-tank member to the main body, then the connection strength is improved, but the number of parts increases and assembly time increases

Engineering Contradiction:

Improveconnection strengthVSAvoidnumber of parts

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The sealing function and fixing function are merged into a single integrated structure. The sealing member is elastically deformed to simultaneously achieve sealing and mechanical fixation, eliminating the need for separate screws or fasteners. This reduces the number of parts while maintaining connection strength.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mechanical screw-fastening system is replaced with an elastic deformation-based fixing mechanism. The sealing member's elasticity provides the necessary clamping force and mechanical interlocking, substituting the traditional screw system with a more integrated elastic mechanical solution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If screws or similar fasteners are used to fix the sub-tank member to the main body, then the connection strength is improved, but the assembly time increases

Engineering Contradiction:

Improveconnection strengthVSAvoidassembly time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The connection structure is segmented into protrusion and recess portions that engage with each other, allowing for simple snap-fit assembly. This segmentation enables quick alignment and connection without requiring multiple fastening operations, significantly reducing assembly time.

Inventive Principle:

Principle #1Segmentation

3Reliability

If multiple fixing members are used to ensure sealing, then the sealing reliability is improved, but the contact pressure becomes uneven due to dimensional errors

Engineering Contradiction:

Improvesealing reliabilityVSAvoiddimensional accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The sealing mechanism utilizes elastic deformation of the sealing member to compensate for dimensional variations. By changing the physical state of the sealing member from rigid to elastic, the system can accommodate manufacturing tolerances and maintain uniform contact pressure across the sealing surface, ensuring reliable sealing without requiring high dimensional precision.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastic sealing member acts as a cushioning element that anticipates and compensates for dimensional errors before they affect sealing quality. The elasticity provides a buffer that equalizes contact pressure even when component dimensions vary within tolerance ranges, preventing uneven stress distribution.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If a simple fitting structure is used to reduce parts, then the assembly productivity is improved, but the sealing reliability may be compromised

Engineering Contradiction:

Improveassembly productivityVSAvoidsealing reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sealing member functions as a flexible elastic element that can deform to conform to the mating surfaces. This flexibility allows the simple fitting structure to maintain reliable sealing by adapting to surface irregularities and dimensional variations, achieving both assembly simplicity and sealing reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20260034797A1Liquid ejection head and liquid ejection apparatus

Publication Date: 2026.02.05 CANON KK

AI summary

A liquid ejection head includes a main body having a first connected portion and a second connected portion, a tank stored within the main body, a first surface provided with a first connecting portion and a second surface provided with a second connecting portion, and a plurality of sealing members interposed between the first connecting portion and the first connected portion and between the second connecting portion and the second connected portion. One of the first connecting portion and the first connected portion is a first protrusion on which the sealing member is externally fitted, the other is a first recess in which the sealing member is internally fitted, one of the second connecting portion and the second connected portion is a second protrusion on which the sealing member is externally fitted, and the other is a second recess in which the sealing member is internally fitted.