If colour moves during a long run, check the ink condition before changing impression or anilox settings. Solvent or water loss and rising temperature alter how ink circulates and transfers from the anilox to the plate and substrate. The viscosity target must belong to that ink, press and job. Measure it in a repeatable way, record temperature with the reading and control additions so the final reel is produced under the same conditions as the approved first reel.
Why viscosity changes on press
Evaporation, heat generated by circulation and the surrounding production environment can change an ink’s flow behaviour. Manual cup readings provide useful spot checks, but they only describe the sample at one moment and depend on consistent sampling technique and temperature.
As viscosity moves, colour strength, transfer, drying and print cleanliness may move with it. Operators can then spend more time making corrections, while ink and substrate are consumed during the adjustment.
How automatic control works
An inline system continuously measures the circulating ink and compares the reading with an approved setpoint. When the measured condition moves outside the selected tolerance, the controller can make a controlled fluid addition and allow sufficient mixing time before evaluating the next correction.
Temperature should be considered alongside viscosity because the two are linked. Monitoring both gives the operator a clearer picture of the ink condition and helps avoid treating a temperature-driven change as a formulation problem.
- Continuous measurement rather than occasional sampling
- Controlled correction around an approved setpoint
- Clear visibility of viscosity and temperature
- Repeatable settings for recurring work
- Reduced dependence on reactive manual adjustment
Define the process before choosing equipment
Document the ink type, solvent or water addition, number of stations, flow rate, temperature range, cleaning method, hazardous-area requirements and the information operators need to see. A control system must suit the actual circulation loop and production practices.
Good automation does not replace ink preparation. The ink should reach the press close to the intended condition, and the target should be established from an approved colour match or process specification.
Application support in India
Royal Coat represents Canadian manufacturer InkSpec in India for viscosity, temperature and ink-process control solutions. A productive evaluation begins with the press, ink system, current measurement method and quality issue—not simply a request for a sensor.
Questions from production and purchasing teams
What to ask about ink process control
Is an efflux cup still useful with automatic viscosity control?
Yes. Cup readings can support setup and cross-checking, while an inline system provides continuous measurement and control during production.
Why should temperature be monitored with viscosity?
Fluid viscosity responds to temperature. Observing both helps operators understand whether a reading reflects evaporation, temperature change or another process condition.
Does automatic control remove the need for operator checks?
No. Operators still verify ink preparation, colour, circulation, calibration and cleaning. Automation makes the approved condition easier to maintain consistently.