Electrohydrodynamic Print Head Layout to Prevent Nozzle Ink Pooling

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Solution Overview

Problem

Ink pools can submerge the nozzles in electrohydrodynamic print heads, disrupting their operation.

Innovation Solution

The print head design includes nozzles with projections facing the print target, ejection electrodes on the front side, ink retainers positioned behind the nozzles to prevent ink pooling, and suction ducts to manage ink flow, along with guard electrodes to control the electrical field and reduce ink wetting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nozzles form projections extending along the ejection direction, then ink ejection is enabled, but ink pools can submerge the nozzles and disrupt operation

Engineering Contradiction:

Improveprinting reliabilityVSAvoidink pooling

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A hydrophobic coating is applied to the nozzle projections to create an intermediary layer between the ink and the nozzle surface. This coating repels ink and prevents it from adhering to or submerging the nozzles, allowing the nozzles to maintain their projection structure while avoiding ink pooling issues

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface properties of the nozzle projections are changed by applying a hydrophobic coating, which alters the surface energy and wettability parameters. This parameter change causes ink to bead up and roll off the nozzle surfaces rather than forming pools, resolving the contradiction between maintaining nozzle projections and preventing ink submersion

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If ejection electrodes are placed on the front side of nozzles, then droplet ejection is achieved, but ink can wet the support elements and form pools

Engineering Contradiction:

Improvedroplet ejection capabilityVSAvoidink wetting of support elements

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A hydrophobic coating is applied to the support elements to create an intermediary protective layer. This coating acts as a barrier that prevents ink from wetting and adhering to the support elements, allowing the ejection electrodes to function on the front side without causing ink pooling on the support structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of ink wetting is extracted from the support elements by applying hydrophobic coating, separating the support elements from direct ink contact while maintaining the ejection electrode functionality on the front side

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If guard electrodes are added to protect ink retainers from electrical field, then ink wetting is reduced, but device complexity increases

Engineering Contradiction:

Improveink wetting around retainersVSAvoidnumber of electrodes

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A hydrophobic coating is applied to the ink retainers to create an intermediary protective layer that repels ink. This eliminates the need for guard electrodes by providing a passive chemical barrier, reducing device complexity while still preventing ink from wetting around the retainers

Inventive Principle:

Principle #24Intermediary (Mediator)

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 prevents nozzle submersion by ink pools, ensuring reliable and uniform ink ejection, enhancing printing reliability and efficiency.

Implementation Method 1

electrohydrodynamic print head

Methodology Applied

Scientific EffectElectrohydrodynamics: Electrohydrodynamics

Implementation Method 2

the electric field of the ejection electrode tends to decrease the surface tension of the ink

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS12558896B2Electrohydrodynamic print head with ink pinning

Publication Date: 2026.02.24 SCRONA AG

AI summary

The electrohydrodynamic print head comprises a nozzle carrier with a plurality of nozzles arranged thereon. A plurality of electrodes associated with the nozzles are located on the front side of the nozzles. A support structure supporting the electrodes is located on the nozzle carrier and comprises a plurality of support elements arranged between the nozzles. Ink retainers are arranged between the nozzles and the support elements. The front surfaces of the ink retainers are located behind the front ends of the nozzles in order to prevent the nozzles from being submerged by ink. Guard electrodes can be provided between the ejection electrodes and the ink retainers to reduce the electrical fields at the ink retainers and thereby to improve their efficiency to pin the ink. Suction ducts surrounding each nozzle allow to remove ink from the nozzles.