Non-circular Ejection Port and Groove for Liquid Circulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional liquid ejection heads face challenges in extending the liquid circulation effect near the meniscus while suppressing the mixing of bubbles, which can disrupt ejection operations.

Innovation Solution

A liquid ejection head design featuring a non-circular ejection port and a groove portion extending in the circulation direction, connected to the ejection port, which reduces bubble mixing and enhances liquid circulation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the meniscus is retreated to extend liquid circulation effect, then the circulation effect is improved, but the risk of bubble intake increases

Engineering Contradiction:

Improveliquid circulation effectVSAvoidbubble mixing risk

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The ejection port is designed with a non-circular shape, creating asymmetric flow patterns that extend liquid circulation near the meniscus while suppressing bubble intake through directional flow control

Inventive Principle:

Principle #4Asymmetry

2Productivity

If a groove is provided to extend circulation effect, then the circulation effect is improved, but bubbles are guided into the pressure chamber

Engineering Contradiction:

Improveliquid circulation effectVSAvoidbubble guidance into pressure chamber

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The non-circular ejection port shape creates asymmetric flow resistance that directs liquid circulation along specific paths while preventing bubbles from being guided into the pressure chamber through the groove

Inventive Principle:

Principle #4Asymmetry

3Productivity

If the meniscus is exposed to atmosphere, then liquid circulation is enhanced, but the meniscus takes in atmosphere as bubbles

Engineering Contradiction:

Improveliquid circulationVSAvoidatmosphere intake as bubbles

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The asymmetric non-circular ejection port shape creates directional flow patterns that enhance liquid circulation while the flow resistance distribution prevents atmosphere from being drawn into bubbles at the meniscus

Inventive Principle:

Principle #4Asymmetry

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

The design effectively extends the liquid circulation effect near the meniscus while minimizing bubble mixing, ensuring stable ejection operations by optimizing the flow resistance and circulation efficiency.

Implementation Method 1

an inkjet printing head uses a thin-film piezoelectric element as an ejection energy generation element

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10875305B2Liquid ejection head

Publication Date: 2020.12.29 CANON KK

AI summary

A liquid ejection head includes a substrate in which an ejection port for ejecting liquid is formed, a pressure chamber to house the liquid to be ejected from the ejection port and apply pressure to the liquid in the ejection, and a flow passage connected to the pressure chamber and configured to cause the liquid in the pressure chamber to circulate along the substrate. The ejection port has a non-circular shape, and the substrate is provided with a groove portion extending in a direction of the circulation and connected to the ejection port. According to the above-described configuration, the liquid ejection head can sufficiently extend a liquid circulation effect to a position near a meniscus while suppressing mixing of bubbles.