Rotary Printing Machine Electrostatic Charge Neutralization

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Solution Overview

Problem

Rotary printing machines face issues with unwanted electrostatic charging of printing materials, leading to voltage flashovers and safety hazards during handling and processing, especially when using insulating materials like plastic films and composite materials.

Innovation Solution

The rotary printing machine incorporates a system with multiple printing units, each with a printing cylinder and impression roller, where devices generate an electrical field using high-voltage sources of different polarities, connected via switching devices to apply either positive or negative polarity voltages, ensuring minimal charging by optimizing the electric field configuration and using field strength measuring devices for automatic control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If electrostatic printing aids with high voltage are used to improve ink transfer and print quality, then print quality is improved, but unwanted electrostatic charging of the printing material occurs leading to safety hazards

Engineering Contradiction:

Improveprint qualityVSAvoidelectrostatic charging and voltage flashovers

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A field strength measuring device detects the charge level on the printing material before it leaves the printing unit, and a discharge device is activated to neutralize the charge. This preliminary detection and counter-action prevents the accumulation of dangerous voltage levels that would otherwise cause flashovers and safety hazards during handling.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The field strength measuring device continuously monitors the electrostatic charge on the printing material and provides feedback to control the discharge device. This feedback mechanism ensures that the discharge device operates only when necessary to maintain safe charge levels, balancing print quality enhancement with safety.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If multiple printing units are arranged one behind the other to process different colors, then printing versatility is improved, but the printing material accumulates very high charges impairing subsequent processing

Engineering Contradiction:

Improveprinting versatilityVSAvoidaccumulated electrostatic charges

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The field strength measuring device is positioned after the last printing unit in the printing direction to detect accumulated charges before the material leaves the printing press. The discharge device then neutralizes these charges in advance, preventing problems during subsequent handling, stacking, and processing operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The high charges accumulated from multiple printing units, which would normally be harmful, are detected and neutralized by the discharge device. This converts the problematic charge accumulation into a controlled process, allowing multi-color printing versatility to be maintained without the associated safety and handling issues.

Inventive Principle:

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

3Reliability

If a semiconductive layer with high electrical resistance is used on the impression roller to reduce current, then safety is improved by avoiding sparks, but the charging of printing material still occurs

Engineering Contradiction:

Improvesafety by avoiding sparksVSAvoidelectrostatic charging of printing material

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The field strength measuring device acts as an intermediary between the printing process and the discharge device. It detects the charge level on the printing material and triggers the discharge device to neutralize excessive charges, providing a safety mechanism that works in conjunction with the semiconductive layer rather than replacing it.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The passive semiconductive layer approach is supplemented by an active electronic monitoring and discharge system. The field strength measuring device and discharge device replace reliance solely on the semiconductive layer's resistance properties, providing a more reliable and controllable solution to the charging problem.

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 configuration significantly reduces unwanted charging on the printing material, enhancing safety and handling by minimizing voltage flashovers and ensuring proper discharge, even when using insulating materials.

Implementation Method 1

A device for generating an electrical field in the printing gap between the printing cylinder and the impression cylinder

Methodology Applied

Scientific EffectElectrical field generation: Electric Field

Implementation Method 2

The impression roller or impression roller has a (semi-)conductive layer on its circumference to which a high voltage is transmitted

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

an electrical field is generated in the area of the printing gap between the printing cylinder and the impression cylinder, which exerts a force on the ink in the cells of the printing cylinder

Methodology Applied

Scientific EffectElectrostatic charge storage: Electrostatics

Implementation Method 4

The resistance of the insulating layer is preferably selected in such a way that it allows the impression roller to discharge slowly after the printing press has been switched off

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP3072689B1Rotary printing machine with devices for reducing charging of print substrate

Publication Date: 2019.01.23 DETTKE HUBERTUS

Figure 1
Figure 2(a)~2(f)
Figure 3

AI summary

Rotary printing press with an electrically essentially insulating substrate (12) on a take-up reel (11), from which the substrate is guided to several printing units (1.1-1.4) arranged one behind the other in the direction of travel of the substrate, each of which has a printing cylinder (2.1-2.4) and an impressionist (4.1-4.4) which unwind in opposite directions, and a device for generating an electric field (9.1-9.4) in the printing gap (10.1-10.4) between the printing cylinder and impressionist, wherein the devices for generating an electric field (9.1-9.4) of different printing units are connected to high-voltage sources (5.1-6.4) which have different polarities, and with a take-up reel (15) onto which the substrate is guided behind the printing units, characterized in that each device for generating an electric field (9.1-9.4) is connected via a switching device (7.1-7.4) to a High voltage source of positive polarity (5.1-5.4) and a high voltage source of negative polarity (6.1-6.4) so that by switching the switching device (7.1-7.4) either a high voltage of positive polarity or a high voltage of negative polarity can be applied to the device for generating the electric field (9.1-9.4).