Introduction
In Continuous Inkjet (CIJ) printing, the quality of the printed code depends on more than just ink color or drying time. Three essential physical parameters — viscosity, surface tension, and conductivity — govern how ink behaves inside the printer and on the substrate.
This article explains what each of these terms means, how they influence inkjet performance, and what to watch for when choosing or troubleshooting CIJ ink.
1. What Is Viscosity in Inkjet Ink?
Viscosity measures a fluid’s resistance to flow — or in simpler terms, how “thick” the ink is. Measured in centipoise (cP), CIJ inks typically fall in the range of 2–4 cP.
Why Viscosity Matters:
- Affects ink drop formation and flight path
- Too low: splashing, satellite drops, poor contrast
- Too high: jet instability, missed codes, nozzle clogging
How CIJ Printers Manage It:
CIJ printers automatically adjust viscosity by adding make-up fluid to compensate for solvent evaporation. That’s why solvent selection and make-up fluid compatibility are critical.
2. What Is Surface Tension?
Surface tension describes the cohesive force between ink molecules that lets a drop form cleanly. It’s typically measured in dynes/cm. CIJ ink surface tension usually ranges from 25 to 40 dynes/cm.
Why Surface Tension Matters:
- Ensures proper drop breakup from the ink stream
- Prevents nozzle dripping or misting
- Ensures adhesion and spread control on the substrate
Low vs. High Surface Tension:
- Too low: overspreading on surface, fuzzy codes
- Too high: poor adhesion, inconsistent drop formation
3. What Is Conductivity in Inkjet Inks?
Conductivity is the ability of the ink to carry an electric charge. It is measured in microsiemens per centimeter (µS/cm). In CIJ printers, ink needs to be conductive so the ink stream can be charged and deflected by the printer’s electrodes.
Why Conductivity Matters:
- Enables precise ink droplet deflection for character formation
- Too low: weak charge, drop misses target, distorted codes
- Too high: electrical noise, signal interference, misprints
Typical Conductivity Ranges:
- CIJ dye-based ink: 500–2000 µS/cm
- CIJ pigment ink: 800–2500 µS/cm
4. How These Three Parameters Work Together
| Parameter | Main Function | Risk When Out of Spec |
|---|---|---|
| Viscosity | Controls ink flow and jet formation | Nozzle clogging or poor drop ejection |
| Surface Tension | Maintains drop shape and substrate contact | Overspreading or adhesion failure |
| Conductivity | Enables precise droplet charging | Distorted or unreadable codes |
5. Monitoring and Maintenance
CIJ printers monitor viscosity and conductivity in real-time using built-in sensors. However, issues can still arise due to:
- Wrong ink or make-up fluid used
- Long idle times leading to solvent evaporation
- Environmental changes (temperature, humidity)
Tips:
- Use only ink-matched make-up fluids
- Keep ink tanks sealed to minimize solvent loss
- Schedule regular maintenance and calibration
6. Cheef CIJ Inks Are Engineered for Balance
At ChinaCIJInk.com, all Cheef inks are formulated with optimal ranges of viscosity, surface tension, and conductivity:
| Ink Code | Viscosity | Conductivity | Notes |
|---|---|---|---|
| C-V420MEK | 2.7 cP | 1150 µS/cm | General-purpose black ink |
| C-V393UV | 2.9 cP | 1200 µS/cm | Invisible UV-readable ink |
| C-W485WHITE | 3.4 cP | 1800 µS/cm | White pigment ink for cables |
Conclusion
Understanding and controlling viscosity, surface tension, and conductivity is essential for successful CIJ printing. These physical properties ensure that ink flows, breaks, charges, and adheres correctly across diverse industrial conditions. At ChinaCIJInk.com, every batch is tested and tuned for optimal balance — delivering reliable, high-quality coding for every application.
