Electrostatic Ink Droplet Positioning for Printing Devices

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Solution Overview

Problem

Existing printing technologies face inefficiencies in accurately positioning ink droplets on printed objects due to aerodynamic effects and electrostatic charges, leading to undesirable deflection and ink deposition issues.

Innovation Solution

The implementation of an electrostatic charging system that creates a controlled electric field to influence the trajectory of ink droplets, ensuring precise placement and minimizing microdroplet condensation by aligning the printed object's electrostatic charge with the output device's field, thereby compensating for aerodynamic deflections and preventing unwanted ink deposits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If aerodynamic effects are present during ink droplet delivery, then ink droplets can be delivered contactlessly to predefinable surface areas, but the ink droplet trajectory is deflected leading to positioning inaccuracy

Engineering Contradiction:
Improvecontactless ink deliveryVSAvoidink droplet positioning accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent converts the harmful aerodynamic deflection into a beneficial effect by using electrostatic charging. The printing object is charged electrostatically, creating an electric field that attracts the ink droplets. This electrostatic attraction compensates for and counteracts the aerodynamic deflection, allowing the ink droplets to reach the intended target position despite the air flow effects during contactless delivery.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the electrostatic parameter of the printing object by applying an electrostatic charge. This parameter change creates an electric field that exerts force on the ink droplets, modifying their trajectory. By adjusting the electrostatic charge level, the system can compensate for aerodynamic deflection and achieve accurate positioning during contactless ink delivery.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If electrostatic charging is applied to the printing object, then ink droplet positioning accuracy is improved, but unwanted ink deposits form from microdroplets over time

Engineering Contradiction:
Improveink droplet positioning accuracyVSAvoidmicrodroplet deposition
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent implements a feedback control system with a sensor arrangement that detects the electrostatic charge of the printing object and provides a charge-dependent sensor signal. The control device uses this feedback information to adjust the electrostatic charging level, optimizing it to attract ink droplets accurately while preventing excessive charging that would cause microdroplet deposition. This feedback mechanism allows the system to maintain optimal charging levels dynamically.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies just the right amount of electrostatic charging - not too little to fail attracting ink droplets, but not too much to cause microdroplet deposition. The control device regulates the electrostatic charge to an optimal level that provides sufficient attraction for accurate positioning while avoiding excessive charging that would generate harmful microdroplet effects.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If sensor arrangement detects electrostatic charge to control charging, then charging accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveelectrostatic charge detection accuracyVSAvoidcharging control system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical charging control with an electrostatic field-based control system. Instead of using mechanical mechanisms to control ink delivery, the system uses electrostatic charging and detection, which can be controlled electronically through the sensor arrangement and control device, simplifying the overall system while improving precision.

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 enhances the positioning accuracy of ink droplets on the printed object's surface, reducing unwanted ink deposits and maintaining electrostatic charging without continuous power supply, even for insulating materials, thus improving the overall printing efficiency and quality.

Implementation Method 1

The charging arrangement electrically, and in particular electrostatically, charges the printed object, thereby generating an electric field relative to the output device

Methodology Applied
Scientific EffectElectrostatic charge: Electrostatics

Implementation Method 2

generating an electric field relative to the output device. With appropriate selection of the field strength and direction for this electric field, an attractive force acts on the ink droplets

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 3

an attractive force acts on the ink droplets supplied by the output device, influencing the ink droplet's trajectory between the output device and the printed object

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatic Induction

Implementation Method 4

charging the printed object serves to direct microdroplets, also known as microsatellites, generated when the ink droplet detaches from the output device, onto the printed object, thus preventing these microdroplets from settling elsewhere

Methodology Applied
Scientific EffectElectrostatic direction: Electrostatic Induction

Data Source

PatentEP3088189B1Printing device and method for printing a printed object
Publication Date: 2020.11.18 HINTERKOPF
  • EP3088189B1 patent drawingFigure 1
  • EP3088189B1 patent drawingFigure 2~5

AI summary

The invention relates to a printing device for printing on a print object (6), comprising an output device (22) configured for dispensing ink droplets onto an exit surface (23), and a receiving device (4) for a print object (6), which is configured for relative movement of the print object (6) relative to the output device (22) to carry out the printing process and which is arranged opposite the exit surface (23) to enable contactless delivery of ink droplets onto predefinable surface areas (25) of the print object (6). According to the invention, a charging arrangement (30; 60) is associated with the output device (22) and/or the receiving device (4), which is configured for an electric charge flow onto the print object (6) to generate an electric field opposite the output device (22).