Low Voltage Electrostatic Aid for Rotogravure Printing

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Solution Overview

Problem

Existing electrostatic assistance apparatuses for rotogravure printing pose safety risks due to high-voltage cables near pressing cylinders and require excessive pressure to ensure ink transfer, leading to issues like 'missing dots' and potential fires.

Innovation Solution

An electrostatic assistance apparatus powered by low voltage (24Vdc) with an integrated generator body and antistatic systems for eliminating static electricity, using a direct or non-contact electrostatic transmitter to charge the pressing cylinder, eliminating the need for high-voltage cables and reducing pressure on the pressing cylinder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external high-voltage generators are used with high-voltage cables connected to pressing cylinders, then electrostatic assistance for ink transfer is achieved, but safety risks increase due to cable deterioration and fire hazards

Engineering Contradiction:

ImprovesafetyVSAvoidfire hazard

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the external high-voltage generator and high-voltage cables from the system. Instead, it uses a low-voltage generator (24Vdc) positioned away from the pressing cylinder, connected through a rotary joint that allows safe rotation while maintaining electrical connection. This extraction of the high-voltage source eliminates the fire hazard associated with high-voltage cables near the pressing cylinder.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a rotary joint as an intermediary component between the low-voltage generator and the pressing cylinder. This rotary joint safely transmits electrical power while accommodating the rotation of the pressing cylinder, eliminating the need for high-voltage cables that would otherwise be subject to deterioration and fire risks.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If pressure of the pressing roll is increased to eliminate missing dots, then ink transfer completeness improves, but device complexity and potential safety risks increase

Engineering Contradiction:

Improveink transfer completenessVSAvoidpressing mechanism complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the purely mechanical pressure-based ink transfer system with an electrostatic assistance system. By applying electrostatic charge to the pressing cylinder through the low-voltage generator and rotary joint, ink particles are attracted to the substrate electrostatically, ensuring complete transfer without needing to excessively increase mechanical pressure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If low-voltage generator is positioned inside the apparatus rather than externally, then safety is improved by eliminating high-voltage cables, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidapparatus structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent nests the low-voltage generator inside the printing apparatus structure, specifically positioning it within the framework of the printing unit. This integration allows the generator to be close to the pressing cylinder for effective electrostatic assistance while maintaining safety by using low voltage and eliminating external high-voltage cable connections.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

Ensures safe and accurate ink transfer to materials at higher production speeds without excessive pressure, reducing the risk of fires and improving print quality by generating the required high voltage internally, thus avoiding the hazards associated with external high-voltage cables.

Implementation Method 1

an electrostatic transmitter (11, 111, 207) for the electrostatic charging of the pressing cylinder (1)

Methodology Applied

Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 2

produce an electrostatic field between a web and a printing roller for aiding transfer of ink from the printing roller to the web

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Implementation Method 3

antistatic systems for eliminating the static electricity

Methodology Applied

Scientific EffectStatic electricity elimination: Electrostatic Discharge

Data Source

PatentEP3231610B1Apparatus for providing an electrostatic aid to a rotogravure printing

Publication Date: 2018.05.09 ACE DI BARBUI DAVIDE & FIGLI SRL

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AI summary

An electrostatic assistance apparatus for rotogravure printing comprising a pressing cylinder (1), antistatic systems for eliminating the static electricity, and an electrostatic transmitter (11, 111, 207) for the electrostatic charging of the pressing cylinder (1); the apparatus is characterized in that it comprises a generator (8, 108, 208) powered with low voltage, advantageously 24Vdc.