Liquid Ejection Unit Pressure Adjustment Displacement Member

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Solution Overview

Problem

Existing liquid ejection devices, such as those described in Japanese Patent No. 5716213, are not suitable for ejecting highly viscous liquids as they often result in liquid droplets adhering to the ejection port rather than being successfully ejected.

Innovation Solution

A liquid ejection unit comprising a liquid holding section, a pressure adjustment section, and a displacement member that adjusts the pressure of the liquid and displaces it from the holding section, allowing for effective ejection of highly viscous liquids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piezoelectric element is used to deform the flow path and push out liquid, then liquid ejection is achieved, but highly viscous liquids cannot be properly ejected and droplets adhere to the ejection port

Engineering Contradiction:
Improveliquid ejection reliabilityVSAvoidadaptability to different liquid viscosities
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention transforms the static flow path into a dynamic system by introducing a movable displacement member that can be positioned at different locations within the liquid holding section. This displacement member dynamically adjusts the liquid's position and pressure distribution, enabling effective ejection of highly viscous liquids that cannot be handled by the fixed piezoelectric element alone

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The displacement member acts as an intermediary between the pressure adjustment section and the liquid. It receives pressure adjustments and translates them into effective liquid displacement and ejection, mediating the force transmission to overcome the high viscosity resistance that the piezoelectric element cannot directly overcome

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If pressure is applied from the piezoelectric element to the flow path, then liquid is pushed out, but liquid droplets form on the ejection port and do not fly to the target object

Engineering Contradiction:
Improveliquid ejection efficiencyVSAvoidliquid droplet detachment reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The displacement member performs preliminary action by positioning itself to adjust liquid pressure and create proper pressure distribution before the actual ejection occurs. This preliminary pressure adjustment ensures that when the liquid is pushed toward the ejection port, it maintains proper momentum and detaches cleanly rather than adhering to the port

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the pressure distribution parameters within the liquid holding section by introducing the displacement member. This creates a gradient pressure field that differs from the uniform pressure applied by the piezoelectric element alone, enabling proper liquid flow and detachment dynamics for highly viscous liquids

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the flow path is deformed using the piezoelectric element, then liquid is pushed out through the flow path, but the mechanism is not appropriate for highly viscous liquids

Engineering Contradiction:
Improveejection mechanism simplicityVSAvoidsuitability for different liquid types
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The displacement member is designed with multi-functionality: it can be positioned at different locations within the liquid holding section to handle different liquid viscosities and ejection requirements. This universal component enables the same ejection mechanism to effectively handle various liquid types including highly viscous liquids, dispersion liquids, and solutions without requiring different specialized mechanisms

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

The proposed solution enables the appropriate ejection of highly viscous liquids by adjusting the pressure and displacing the liquid, reducing the risk of droplets adhering to the ejection port and ensuring successful delivery.

Implementation Method 1

a pressure adjustment section which is configured to adjust a pressure of a liquid held in the liquid holding section

Methodology Applied
Scientific EffectPressure adjustment: Pressure Increase

Implementation Method 2

a displacement member which is configured to displace at least a part of the liquid whose pressure is adjusted and eject the liquid from the liquid holding section

Methodology Applied
Scientific EffectPressure-driven displacement: Pressure Gradient

Data Source

PatentEP3827990B1Liquid ejection unit and liquid ejection device
Publication Date: 2025.05.14 RICOH CO LTD
  • EP3827990B1 patent drawingFigure 1
  • EP3827990B1 patent drawingFigure 2
  • EP3827990B1 patent drawingFigure 3A~3D

AI summary

A liquid ejection unit includes: a liquid holding section which has an ejection port through which a liquid is ejected and which holds the liquid; a pressure adjustment section which is configured to adjust a pressure of a liquid held in the liquid holding section; and a displacement member which is configured to displace at least a part of the liquid whose pressure is adjusted and eject the liquid from the liquid holding section.