Liquid Ejection Head Interface Control via Flow Rate Ratios

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Solution Overview

Problem

Existing liquid ejection heads struggle to control the interface between ejection and bubbling media effectively, leading to unstable ejection operations and performance issues such as inconsistent ejection amount and velocity.

Innovation Solution

A liquid ejection head design that includes multiple modular units with adjustable flow rates and viscosities of ejection and bubbling media, allowing for controlled parallel flows and laminar interfaces, enabling stable ejection operations by adjusting the water phase thickness ratio and flow rate ratio between the two liquids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing liquid ejection heads are used to eject liquid, then ejection operation can be performed, but the interface between ejection and bubbling media cannot be controlled effectively, leading to unstable ejection operations

Engineering Contradiction:

Improveejection operation stabilityVSAvoidinterface control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The liquid ejection head is divided into multiple independent liquid ejection units, each capable of controlling the interface between ejection and bubbling media separately. This segmentation allows for precise control of the liquid-liquid interface in each unit, improving ejection stability without requiring complex system-wide control mechanisms.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each liquid ejection unit is designed with specific local characteristics including defined ejection ports, pressure chambers, and liquid supply paths. The interface between ejection and bubbling media is controlled at the local level within each unit, allowing for optimized performance without increasing overall device complexity.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If existing liquid ejection heads are used, then ejection can be performed, but ejection amount and velocity are inconsistent

Engineering Contradiction:

Improveejection amount and velocity consistencyVSAvoidflow rate and viscosity control complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The liquid ejection head enables dynamic control of flow rates and viscosities of both ejection and bubbling media through adjustable liquid supply paths and pressure chambers. This dynamic adjustment capability allows for precise control of ejection amount and velocity by optimizing the flow characteristics of liquids in real-time, improving manufacturing precision.

Inventive Principle:

Principle #15Dynamics

3Reliability

If modular units with adjustable flow rates and viscosities are implemented, then ejection performance is enhanced, but device complexity increases

Engineering Contradiction:

Improveejection performanceVSAvoidmodular unit configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each liquid ejection unit is designed as a modular component that can perform multiple functions: controlling the interface between liquids, regulating flow rates, adjusting viscosities, and enabling ejection. This multi-functionality reduces the need for separate dedicated components, thereby managing device complexity while enhancing performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design stabilizes the interface between the ejection and bubbling media, enhancing the ejection performance by maintaining a predetermined ejection amount and velocity, and allowing for flexible component selection in the ejection and bubbling media, improving manufacturing yield and reducing replacement costs.

Implementation Method 1

a pressure generation element configured to apply pressure to the first liquid to form a meniscus in contact with the second liquid in the channel

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

an ejection port configured to eject droplets of the second liquid with or without the first liquid

Methodology Applied

Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP3603977B1Liquid ejection head and liquid ejection module

Publication Date: 2024.03.27 CANON KK

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AI summary

A liquid ejection head (1) includes a pressure chamber (18) that allows a first liquid (31) and a second liquid (32) to flow inside, a pressure generation element (12) that applies pressure to the first liquid (31) and an ejection port (11) that ejects the second liquid (32). The first liquid (31) and the second liquid (32) that flows on a side closer to the ejection port (11) than the first liquid flow in contact with each other in the pressure chamber (18). On that basis, the first liquid (31) and the second liquid (32) flowing in the pressure chamber (18) satisfy 0.0<0.44Q2/Q1−0.322η2/η1−0.109<1.0, where η1 is a viscosity of the first liquid (31), η2 is a viscosity of the second liquid (32), Q1 is a flow rate of the first liquid (31), and Q2 is a flow rate of the second liquid (32).