Ink Jet Print Head Using Lorentz Force for Droplet Acceleration

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Solution Overview

Problem

Inkjet printheads face challenges in maintaining image quality when printing on uneven surfaces due to the inability to bring the printhead close enough, resulting in blurring caused by ink droplets being slowed and deflected by air molecules over longer distances.

Innovation Solution

An inkjet printhead with an exit channel that generates a current flow through electrically conductive liquid droplets, utilizing a magnetic field to accelerate them via Lorentz force, ensuring a stable trajectory and increased kinetic energy without increasing droplet mass or speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ink jet print head is brought closer to the substrate surface to maintain image quality, then the trajectory stability of liquid droplets is improved, but the adaptability to uneven surfaces is worsened

Engineering Contradiction:
Improvetrajectory stabilityVSAvoidadaptability to uneven surfaces
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by transitioning from a static printing system to a dynamic one where the liquid droplet is continuously accelerated after ejection. The acceleration means (electrodes generating electric field) actively modifies the droplet's motion state in real-time, allowing the system to maintain trajectory stability regardless of the distance to the substrate, thus resolving the contradiction between proximity requirement and surface adaptability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the velocity parameter of the liquid droplet dynamically after ejection. By applying acceleration through electric fields generated by electrodes, the droplet's speed is increased during flight, which stabilizes its trajectory and compensates for the effects of air molecules. This parameter change allows printing at variable distances while maintaining image quality

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the distance between the ink jet print head and the substrate is increased to accommodate uneven surfaces, then the adaptability to complex surfaces is improved, but the image quality is worsened due to droplet blurring

Engineering Contradiction:
Improveadaptability to complex surfacesVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system becomes dynamic by continuously accelerating the droplet during its flight path through electric fields. This dynamic acceleration compensates for the destabilizing effects of increased flight distance and air molecule collisions, allowing the system to operate at larger distances from uneven surfaces while maintaining precise droplet placement and image quality

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The acceleration means (electrodes generating electric field) acts as an intermediary between the droplet ejection and the substrate. This intermediary mechanism actively modifies the droplet's trajectory and velocity during flight, enabling the system to bridge larger gaps to complex surfaces without sacrificing precision

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the kinetic energy of the liquid droplet is increased by increasing droplet speed to stabilize trajectory, then the trajectory stability is improved, but the device complexity is worsened due to additional acceleration components

Engineering Contradiction:
Improvetrajectory stabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrodes in the acceleration means serve multiple functions: they generate the electric field for droplet acceleration, control the droplet trajectory, and can be integrated with the existing ink jet print head structure. This multi-functionality reduces the need for separate complex acceleration mechanisms, thereby limiting the increase in device complexity while achieving trajectory stability

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

Solution Approach 2:

The patent replaces potential mechanical acceleration systems with an electromagnetic field-based acceleration mechanism. By using electric fields generated by electrodes to accelerate the conductive liquid droplet, the system avoids complex mechanical moving parts, reducing device complexity while achieving the required trajectory stability through non-contact force application

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for more stable and accelerated ink droplet trajectories, enabling high-quality printing over larger distances without compromising image quality, even on complex surfaces.

Implementation Method 1

an acceleration means is provided at the outlet channel, which is adapted to generate a current flow through the electrically conductive liquid droplet and a magnetic field in order to accelerate the electrically conductive liquid droplet by means of a force in the outlet channel in the direction of the substrate to be printed

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP4126551B1Ink jet print head
Publication Date: 2023.08.23 PHOENIX CONTACT GMBH & CO KG

AI summary

The invention relates to an ink jet print head for printing on a substrate, comprising: at least one nozzle, adapted to dispense at least one electrically conductive liquid droplet; and an outlet duct arranged on the nozzle, through which outlet duct the electrically conductive liquid droplet can be dispensed in the direction of the substrate to be printed on; wherein an accelerating means is provided on the outlet duct and is adapted to generate a current flow through the electrically conductive liquid droplet and to generate a magnetic field in order to accelerate the electrically conductive liquid droplet by means of a force in the outlet duct in the direction of the substrate to be printed on. The invention also relates to a printing apparatus and a method for printing on a substrate.