What are the main hazards of static electricity in gravure printing and how do they affect production?

The main hazards of static electricity in gravure printing include ink atomization (fly ink) when the voltage is > ±3kV, which can cause an annual ink loss of up to ¥850,000 for a soft packaging factory and also pollute the equipment and workshop environment. When the surface resistance of materials is > 10¹²Ω, it will lead to dust adsorption on materials, increasing the defective rate of tobacco packaging printing by 18% and affecting brand image and market access. Static electricity with an electrostatic force > 5N/m² can cause registration deviation, for example, a film printing enterprise saw a 9% increase in roll scrap rate due to electrostatic interference, with single-production losses exceeding ¥200,000. These issues seriously threaten product quality and production efficiency, and may also cause brand reputation damage.

What are the effective technical solutions to eliminate static electricity in gravure printing and how do they work?

There are five main technical solutions to eliminate static electricity in gravure printing. The ionizing bar system generates positive and negative ions through high-frequency alternating current to neutralize electrostatic charges on material surfaces, with an ionization balance within ±15V. Conductive guide rolls use carbon fiber composite rollers (resistance ≤10⁴Ω) to rapidly conduct surface static electricity to grounding devices, and the roller surface temperature should be ≤40℃ during operation. Humidity control increases the workshop humidity (50-65% RH) to lower air resistance and inhibit charge accumulation, using ultrasonic humidifiers with ±3% humidity control precision. Antistatic inks add 0.5-1.2% graphene dispersion to reduce the surface resistance of the ink to 10⁸Ω and weaken electrostatic adsorption. Electrostatic elimination brushes discharge static electricity through direct contact with material surfaces using metal fiber brushes, with a distance of 3-5mm maintained between the brushes and materials for effective contact.

How to solve the static electricity problem in gravure printing

Date: May 01 2025 From: Star Color Views:

In the modern packaging and printing industry, gravure printing is widely used in packaging production for food, pharmaceuticals, tobacco, and other sectors due to its high precision, abrasion resistance, and excellent color performance. However, with the trend toward high-speed and automated production, electrostatic problems have become increasingly prominent, seriously threatening product quality and production efficiency. In accordance with the requirements of the national standard GB/T 12703.1-2021, controlling electrostatic voltage below ±1kV and ink atomization rate ≤0.3% has become a core technical goal for the industry. Based on the latest 2023 technological achievements, this whitepaper systematically addresses the hazards, solutions, and implementation paths for electrostatic issues in gravure printing.

1. Quantitative Analysis of Electrostatic Hazards

Electrostatic issues in gravure printing lead to measurable economic losses and quality risks. The table below reveals the severity of these hazards through industry test data:

Problem Manifestation	Critical Threshold	Testing Equipment	Industry Loss Case
Ink Atomization (Fly Ink)	Voltage > ±3kV	Trek 520 Electrostatic Meter	A flexible packaging factory incurred an annual ink loss of ¥850,000 due to fly ink, while also polluting equipment and the workshop environment.
Dust Adsorption on Materials	Surface Resistance > 10¹²Ω	ACL-385 Resistance Tester	Dust adhesion in tobacco packaging printing increased the defective rate by 18%, directly impacting brand image and market access.
Registration Deviation	Electrostatic Force > 5N/m²	Simco Electrostatic Field Mapping System	A film printing enterprise saw a 9% increase in roll scrap rate due to electrostatic interference, with single-production losses exceeding ¥200,000.

Typical Case: In a dry summer environment, a tobacco packaging company failed to control static electricity effectively, causing PET aluminized film to adsorb significant workshop dust. This led to spot defects in printed products, resulting in ¥350,000 in rework and scrap costs in a single month, along with delivery delays and brand reputation damage.

Gravure printing

2. Five Core Electrostatic Elimination Technologies

1. Ionizing Bar System

Principle: Generates positive and negative ions via high-frequency alternating current to neutralize electrostatic charges on material surfaces.
Parameter Standard: Ionization balance must be controlled within ±15V to ensure stable ion output.
Application Case: After installing the Fraser 3055XLR ionizing bar (coverage width 1.2m, response time <0.1s) in a daily chemical packaging production line, electrostatic voltage dropped from ±5kV to ±800V, reducing fly ink loss by 68%.
Cost-Effectiveness: Equipment cost is approximately ¥38,000 per set, with an average payback period of 6 months through reduced ink waste and scrap rates.

2. Conductive Guide Rolls

Principle: Uses carbon fiber composite rollers (resistance ≤10⁴Ω) to rapidly conduct surface static electricity to grounding devices.
Parameter Standard: Roller surface temperature must remain ≤40℃ during operation to avoid material performance degradation.
Test Data: A film printing enterprise reduced fly ink loss from 2.1% to 0.6% (72% decrease) after replacing standard rolls with conductive ones.

3. Humidity Control

Principle: Increases workshop humidity (50-65% RH) to lower air resistance and inhibit charge accumulation.
Equipment Selection: Ultrasonic humidifiers with ±3% humidity control precision ensure environmental stability.
Economic Benefit: A food packaging factory saved ¥24,000 annually in scrap disposal costs and reduced equipment cleaning frequency after implementing humidity control.

4. Antistatic Inks

Principle: Adds 0.5-1.2% graphene dispersion to ink, reducing surface resistance to 10⁸Ω and weakening electrostatic adsorption.
Application Effect: A pharmaceutical packaging company increased yield from 78% to 93% using antistatic inks. Despite a 15% increase in raw material costs, overall profits improved significantly.

5. Electrostatic Elimination Brushes

Principle: Metal fiber brushes discharge static electricity through direct contact with material surfaces for localized charge release.
Installation Standard: Maintain a 3-5mm distance between brushes and materials for safe and effective contact.
Cost Advantage: Single-set installation cost is only ¥6,000, making it suitable for small production lines or localized static control.

3. Production Line Retrofit Steps

1. Electrostatic Mapping and Positioning

Using an electrostatic distribution meter for full-area scanning of the workshop to create a charge thermal map. Field measurements show that high-static zones typically concentrate in the unwinding unit (where initial charges generate due to material friction) and the first color station (where charge accumulation intensifies during ink transfer). Mapping results from a flexible packaging production line reveal that electrostatic voltage at the unwinding unit reaches ±4.2kV, with peaks of ±6.8kV in the first color station area—zones requiring priority treatment.

2. Equipment Selection and Installation

Taking the Fraser 3055XLR ionizing bar as an example, install it 50-80mm from the material surface at a 30° angle to ensure uniform ion coverage. A printing enterprise achieved ±900V electrostatic voltage within 30 seconds of installation, meeting national standards.

3. Process Parameter Optimization

Printing Speed-Ionization Frequency Matching: Use the formula f(Hz)=60×W(mm)v(m/min)×1000 (where W is the printed pattern width) for dynamic adjustment. For example, at 150m/min speed and 800mm pattern width, the ionization frequency should be set to 31.25Hz.
Grounding Resistance Control: Use the Fluke 1630 grounding resistance tester to ensure guide roll grounding resistance ≤4Ω for effective static discharge.

4. Real-Time Monitoring System

Integrate the Keyence FX-500 electrostatic sensor with a PLC control system to automatically trigger ion blower compensation when voltage exceeds standards. A tobacco packaging line reduced anomaly response time to 0.5 seconds, preventing production interruptions from sudden static surges.

Gravure printing

4. Material Modification Solutions

Differentiated antistatic treatments are applied based on substrate properties for long-term static control:

Substrate Type	Antistatic Treatment Process	Surface Resistance Change (Ω)	Effective Period
BOPP Film	Coating 0.8g/㎡ alkyl sulfonate	10⁹ → 10⁷	180 days
PET Aluminized Film	Co-extruded antistatic masterbatch (3% content)	10¹⁵ → 10¹⁰	Permanent
Paper	Spraying nano-indium tin oxide (ITO)	10¹³ → 10⁸	Full printing cycle

Test Data: A paper company’s 30-day continuous printing test on ITO-coated paper showed stable surface resistance at ~10⁸Ω, effectively reducing dust adsorption and lowering the printing defective rate by 15%.

Conclusion

By systematically applying the technical solutions outlined here, enterprises can stabilize electrostatic voltage within the GB/T 12703.1-2021 standard (±1kV) and reduce ink atomization rate below 0.3%. The quantitative data and practical guidelines in this whitepaper provide critical technical support for the industry to achieve efficient, green, and intelligent production.