Piezoelectric and Electrohydrodynamic Inkjet Actuator for Precision Droplet Control

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Solution Overview

Problem

Inkjet printing apparatuses face challenges in achieving high-resolution and precision printing, particularly in display and printed electronics fields, where controlling ink droplet ejection and minimizing ink usage are crucial.

Innovation Solution

The integration of piezoelectric and electrohydrodynamic techniques in an inkjet printing apparatus, utilizing a piezoelectric actuator to reduce the pressure chamber volume and an electrohydrodynamic actuator to generate and control ink droplets, with specific voltage applications to eject, accelerate, and restore ink droplets efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If piezoelectric method is used to eject ink droplets, then printing operation control is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveprinting operation controlVSAvoidprinting precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent combines piezoelectric actuator and electrohydrodynamic actuator in a single inkjet printing apparatus. The piezoelectric actuator provides controllable drop-on-demand ejection while the electrohydrodynamic actuator forms minute droplets with high precision, achieving both operational control and manufacturing precision

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The inkjet printing apparatus is designed to perform multiple functions: the piezoelectric actuator handles general ink ejection and operational control, while the electrohydrodynamic actuator handles precision droplet formation. This multi-functional design allows the system to achieve both ease of operation and manufacturing precision through different mechanisms

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If electrohydrodynamic method is used to form minute droplets, then manufacturing precision is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveprinting precisionVSAvoidprinting operation control

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The ink ejection function is segmented into two separate actuators: the piezoelectric actuator handles the ejection control operation, while the electrohydrodynamic actuator handles the precise droplet formation. This segmentation allows each component to specialize in its strength without compromising the other

Inventive Principle:

Principle #1Segmentation

3Loss of substance

If conventional inkjet printing is used, then ink usage is excessive, but productivity is maintained

Engineering Contradiction:

Improveink usageVSAvoidprinting productivity

Core Design Contradiction:

Loss of substanceVSProductivity

Solution Approach 1:

The electrohydrodynamic actuator changes the parameters of ink droplet formation by using electrohydrodynamic forces to create minute droplets with precise control over size and placement. This parameter change enables significant reduction in ink consumption while maintaining printing speed and productivity through the controlled ejection process

Inventive Principle:

Principle #35Parameter changes

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 approach enables precise control over ink droplet ejection, allowing for high-resolution printing with reduced ink usage and minimized nozzle clogging, enhancing the reliability and precision of the printing process.

Implementation Method 1

In the piezoelectric method, ink droplets are ejected by deformation of a piezoelectric material

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

In the electrohydrodynamic method, ink droplets are ejected by an electrohydrodynamic force

Methodology Applied

Scientific EffectElectrohydrodynamic force: Electrohydrodynamics

Implementation Method 3

because an inkjet printing apparatus using the electrohydrodynamic method forms minute droplets of ink with relative ease

Methodology Applied

Scientific EffectElectrohydrodynamic force: Electrohydrodynamics

Data Source

PatentUS8186811B2Inkjet printing apparatus and method of driving inkjet printing apparatus

Publication Date: 2012.05.29 SAMSUNG ELECTRONICS CO LTD

AI summary

An inkjet printing apparatus according to example embodiments may include a flow channel plate including an ink inlet for introducing ink, a pressure chamber containing the introduced ink, and a nozzle connected to the pressure chamber and configured to eject ink. A piezoelectric voltage applier may apply a piezoelectric driving voltage to the piezoelectric actuator in such a way that the volume of the pressure chamber is reduced so as to eject an ink droplet. An electrohydrodynamic voltage applier may apply a first electrohydrodynamic driving voltage and a second electrohydrodynamic driving voltage to the electrohydrodynamic actuator. The first electrohydrodynamic driving voltage may generate a jet from the ink droplet such that the jet is ejected towards a printing medium, and the second electrohydrodynamic driving voltage (which has an opposite polarity to that of the first electrohydrodynamic driving voltage) may restore the ink droplet to the nozzle.