An important factor that determines print quality, particularly in rotogravure and flexographic processes is ink temperature. A constant ink temperature minimises viscosity variations, ensures consistent ink transfer, and delivers superior print quality, even under fluctuating ambient conditions.
Why does ink cooling matter in printing?
Ink cooling systems maintain ink temperature within a defined range, helping to:
- Reduce solvent loss
- Lower VOC (volatile organic compound) odour
- Improve ink pick-up
- Maintain colour consistency throughout the print run
This is why ink cooling systems are now a standard feature in high-performance printing presses.
Graph: solvent consumption at different ink temperatures
Source: GAA study – gravure association of the Americas
Why does ink temperature rise during printing?
In printing presses, ink is constantly recirculated from the ink tank to the ink tray and back. As it travels through pumps, filters, and connecting pipes, it absorbs heat. While agitation in the tank and pump contributes slightly, the main sources of heat include:
- Friction between the doctor blade and the gravure or anilox roller
- Heat from freshly dried film entering the next print station
- Ambient temperature in a closed pressroom
An independent study by the Gravure Association of the Americas (GAA) found that maintaining ink temperatures between 21°C and 25°C can significantly reduce solvent evaporation during the printing process.
The impact of high ink temperatures
When ink temperature rises beyond a certain point, solvents evaporate rapidly, increasing ink solids and altering the pigment-to-solvent ratio. To maintain print quality, operators add more solvent, creating a cycle of constant top-ups and strong VOC odours on the shopfloor.
These effects translate into:
- Higher production costs due to greater ink and solvent usage
- Health risks for machine operators from prolonged VOC exposure
- Increased fire hazards due to greater solvent volatility
Ink cooling systems: a reliable solution for economically maintaining quality
Ink cooling systems, typically mounted at each print station, are compact heat exchangers designed to stabilise the ink temperature during printing. Their core function is to maintain the ink temperature within a pre-set band, typically between 21°C and 25°C, ensuring a consistent ink-solvent mix at each print station, during the production run.
A temperature sensor on each heat exchanger monitors the ink temperature, and a control system opens a solenoid valve for chilled water when cooling is needed. The ink loses heat to the chilled water, remaining within the desired temperature band.
Key benefits of ink cooling systems
Ink cooling systems offer measurable advantages:
- Lower operational costs over time
- Reduced solvent consumption and VOC emissions
- Improved safety and working conditions on the shopfloor
- Consistent colour quality and ink transfer
Conclusion
Ink temperature is a critical parameter in achieving print consistency, managing solvent use, and maintaining shopfloor health. With the right ink cooling system, such as Valflow, printers can achieve high-speed, high-quality output with lower environmental and safety risks.
At AxisValence, we are committed to supporting safety, health, and environmental best practices in industrial printing. Our Valflow ink temperature stabiliser has earned the trust of leading printers across domestic and international markets.