Liquid Ejection Head Dual Pressure Chamber Ink Circulation

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Solution Overview

Problem

Existing liquid ejection heads face challenges in maintaining efficient ink flow and circulation, leading to ink ejection failures due to ink thickening during volatile component evaporation, and struggle to effectively utilize ejection energy for both ink ejection and circulation.

Innovation Solution

The design incorporates a liquid ejection head with a configuration that includes a first pressure chamber for ink ejection and a second pressure chamber for ink circulation, utilizing heating elements or piezoelectric elements to generate energy for both ejection and circulation, with a smaller diameter hole (19) that enhances pressure propagation towards the circulation flow path, allowing for efficient ink circulation and stirring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pressure chamber, ejection energy generating element, and ejection port are used for ink ejection only, then the ink ejection function is simple and reliable, but efficient ink circulation or stirring cannot be performed

Engineering Contradiction:
Improveink circulation efficiencyVSAvoidchamber configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the single pressure chamber into two separate chambers: a first pressure chamber for ink ejection and a second pressure chamber for ink circulation. This segmentation allows each chamber to be optimized for its specific function, enabling efficient ink circulation without compromising the simplicity and reliability of the ejection function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ejection energy generating element is designed to serve dual purposes: it can generate ejection energy for ink ejection from the first pressure chamber and generate flow energy for ink circulation in the second pressure chamber. This multi-functionality allows efficient ink circulation while maintaining the simplicity of using a single ejection energy generating element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If a single pressure chamber is used for both ink ejection and circulation, then the device structure is simple, but efficient ink circulation or stirring cannot be performed with ease

Engineering Contradiction:
Improveink circulation easeVSAvoidchamber structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent divides the single pressure chamber into two separate chambers: a first pressure chamber for ink ejection and a second pressure chamber for ink circulation. This segmentation allows each chamber to be optimized for its specific function, enabling efficient ink circulation without compromising the simplicity of the overall device structure.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the ejection energy generating element is used to generate flow energy for ink circulation, then ink thickening is suppressed, but energy consumption increases

Engineering Contradiction:
Improveink ejection reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The ejection energy generating element is designed to serve dual purposes: it can generate ejection energy for ink ejection from the first pressure chamber and generate flow energy for ink circulation in the second pressure chamber. This multi-functionality allows efficient ink circulation while maintaining reasonable energy consumption by utilizing the existing ejection energy generating element for both functions.

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 configuration ensures a satisfactory ink ejection state by generating a circulating ink flow that prevents ink thickening, maintains efficient ink flow, and allows for precise control of ink ejection, reducing energy consumption and minimizing ink wastage.

Implementation Method 1

suppress the occurrence of an ink ejection failure attributable to thickening of the ink during volatile ink component evaporation from the ejection port

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

capable of ejecting liquid ink in a pressure chamber from an ejection port by pressurizing the ink supplied into the pressure chamber with an ejection energy generating element

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

This printing head has a circulation path for circulating the ink in the pressure chamber

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP3421241B1Liquid ejection head and liquid ejection apparatus
Publication Date: 2020.04.15 CANON KK
  • EP3421241B1 patent drawingFigure 1
  • EP3421241B1 patent drawingFigure 2A~2B
  • EP3421241B1 patent drawingFigure 3A~3B

AI summary

An ejection energy generating element (2) is provided in a first pressure chamber (7) so that a liquid in the first pressure chamber (7) is ejected from an ejection port (9). A pressurization energy generating element (12) is provided in a second pressure chamber (17) so that the liquid in the first pressure chamber (7) is pressurized. An opening area of a hole (19) open to the second pressure chamber (17) is smaller than an opening area of the ejection port (9).