Understanding Conductivity in Small Character Inkjet Printer Inks

Conductivity is a critical parameter in Continuous Inkjet (CIJ) printing systems, affecting ink droplet charging, deflection accuracy, and overall code quality. Proper conductivity management ensures that your printer delivers consistent, readable codes across a wide range of materials and production speeds.

What Is Ink Conductivity?

Conductivity measures how easily electricity can pass through a fluid, expressed in microsiemens per centimeter (µS/cm). In CIJ printing, ink conductivity influences the ability to charge droplets effectively, a key process for steering droplets onto the substrate to form characters.

Why Conductivity Matters in CIJ Printing

• Precise Droplet Charging: Stable conductivity ensures each droplet is properly charged, enabling accurate deflection and clean character formation.
• Print Stability: Consistent conductivity prevents coding drift, misaligned characters, and print errors.
• Machine Protection: Monitoring conductivity protects the charge electrodes, deflection plates, and gutter systems from operational stress.

Typical Conductivity Range for CIJ Inks

Normal conductivity values for solvent-based CIJ inks typically range between:

• 500 to 2500 µS/cm depending on the ink type and formulation.

Exact values vary based on:
– Ink chemistry (MEK-based, ethanol-based, acetone-based)
– Printer brand and model requirements (e.g., Videojet, Domino, Markem-Imaje, Citronix, Leibinger)
– Specific application needs (e.g., UV-readable inks, high-adhesion inks)

How Conductivity Is Measured and Controlled

• Internal Conductivity Sensors: CIJ printers continuously monitor ink conductivity using built-in sensors located within the fluid system.
• Automatic Solvent Adjustment: If conductivity rises (due to solvent evaporation), the printer automatically adds solvent to dilute and stabilize conductivity levels.
• Alarm Systems: If conductivity moves outside preset tolerances, printers generate alerts like “Conductivity Fault” requiring corrective actions.

Factors Affecting Ink Conductivity

• Evaporation: Loss of volatile solvents increases conductivity.
• Contamination: Introduction of water, dust, or other chemicals can drastically alter conductivity values.
• Ink Aging: Over time, ink formulations may degrade, changing their electrical properties.
• Temperature Changes: Conductivity can vary slightly with temperature, although modern printers compensate for this automatically.

Best Practices for Managing Conductivity

• Refill solvent tanks promptly when notified to maintain ink balance.
• Use approved inks and solvents only, avoiding cross-brand or untested fluids.
• Perform regular system cleaning and replace filters as per the maintenance schedule.
• Check conductivity manually during major maintenance events if the printer offers diagnostic tools.

FAQs

• What happens if ink conductivity is too high? Droplet charging may become unstable, leading to misprints, unreadable codes, or complete printing failure.
• What happens if conductivity is too low? Droplets may not charge adequately, causing characters to blur, collapse, or miss target areas.

Conclusion

Maintaining the correct conductivity in small character CIJ printer inks is vital for achieving precise, high-quality coding. With the right consumables, monitoring practices, and maintenance, businesses can ensure stable production and extend equipment life. Need assistance managing your ink system or choosing the right ink formulations? Contact Cheef Inkjet today at sales@cheef.cn!