Inclined Descender Liquid Ejection Head Bubble Management

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Solution Overview

Problem

In liquid ejection heads, air bubbles can collect in areas with slower ink flow rates, leading to ink ejection failures due to absorption of pressure required for droplet ejection.

Innovation Solution

The liquid ejection head incorporates a descender with a specific inclination relative to the communication channel, directing liquid flow to prevent stagnation and facilitate air bubble discharge, thereby ensuring consistent ink ejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the channel extends in a direction orthogonal to the discharge channel, then the structure is simple and easy to manufacture, but air bubbles collect in the downstream portion of the channel causing ink ejection failure

Engineering Contradiction:

Improvechannel structureVSAvoidink ejection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The channel is designed to extend in the X direction (parallel to discharge channel) rather than orthogonally, creating an asymmetric flow path that prevents bubble accumulation while maintaining manufacturing simplicity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The channel orientation is changed from a Y-direction extension (orthogonal to discharge) to an X-direction extension (parallel to discharge), utilizing a different spatial dimension to resolve the bubble accumulation problem

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the flow rate in the downstream portion of the channel is slower, then the ink flow is stable, but air bubbles collect in the slower flow area causing pressure loss

Engineering Contradiction:

Improveink flowVSAvoidpressure

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The channel is positioned asymmetrically parallel to the discharge channel, creating a flow path that maintains stable ink flow while preventing bubble accumulation through optimized geometry

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The design converts the potential harm of slow flow (bubble accumulation) into a benefit by positioning the channel parallel to the discharge channel, where the slow flow does not cause bubble collection and pressure is maintained

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

The solution effectively reduces pressure loss and enhances air bubble discharge, ensuring reliable ink ejection by maintaining smooth liquid flow and preventing stagnation.

Implementation Method 1

the first direction in which the descender extends from the second end toward the first end is inclined toward the communication channel relative to a Y direction orthogonal to the X direction

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11273637B2Liquid ejection head

Publication Date: 2022.03.15 BROTHER KOGYO KK

AI summary

A liquid ejection head includes a nozzle, a pressure chamber configured to receive a pressure to eject liquid from the nozzle, a descender, and a communication channel. The descender has a first end and a second end opposite to each other. The first end is connected to the pressure chamber. The communication channel is connected to the second end and extends from a connection with the second end in an X direction. A first direction in which the descender extends from the second end toward the first end is inclined toward the communication channel relative to a Y direction orthogonal to the X direction.