The Role Of Press Atmosphere On Ink Transfer & Ink Performance

In flexographic printing, concerns with ink drying and viscosity can be caused by atmospheric conditions. On a similar issue, the pace at which you can efficiently operate your press can be affected by these factors. How your ink reacts and performs with the anilox, image carrier, and the substrate is influenced by the pressroom temperature (whether it's too warm, chilly, humid, or arid).

Failure to maintain the ideal pressroom environment for your printing could result in a variety of flexo printing defects as well as a reduction in print quality.

 

Drying & Solution Of Flexo Inks

 

Monitor these factors and make adjustments as needed to best fit your printing needs. We focus on the environment and its impacts on water-based and solvent-based inks among the four most popular types of flexo printing inks.

 

1- HUMIDITY

 

The water component of water-based inks evaporates from the printed substrate as it dries. Water-based inks dry more slowly in humid circumstances and more quickly in arid settings. To optimize the process, you must balance the conditions appropriately. Too much humidity or aridity, if not monitored and adjusted, can cause serious ink transfer and drying issues.

Evaporation is also used to dry solvent-based inks. When there is a lot of moisture in the air, alcohol or acetate-based inks can absorb it. The extra moisture might make polymers in the inkless soluble, resulting in smudged printing. To prevent evaporation before the ink reaches your substrate, cover your ink-delivery systems.

 

2- TEMPERATURE

 

Consider the weather in the winter. Isn't it true that cold air seems drier? (This is why, in extreme cold, our hands become more dry and cracked.)

Warmer air simply absorbs and retains more moisture. As a result, water-based inks dry faster in warm air with low humidity.

The temperature has an influence on solvent-based inks as well, however, the drying effects are less prominent. Solvents, such as alcohol, evaporate faster as the pressroom temperature rises. However, as the temperature rises, a higher level of humidity can be tolerated for evaporation and printing quality.

 

Important: Alcohol-based inks can take longer to cure than water-based inks due to the drying speed of common solvents.

 

3- AIR CIRCULATION

 

Water-based inks require the most drying air passage feasible. Greater air circulation guarantees that moisture-laden air is pushed out and replaced by air that is less wet, aiding the drying process. Try to stay away from dryers that aren't balanced. These can blast air over your flexo sleeves, cylinders, plates, and/or anilox, causing the ink to dry on the substrate before it can fully wet out. Dirty printing can also occur if the ink dries on the anilox, or image carrier.

Dryers for alcohol-based inks are built to allow more solvent to accumulate before the air is removed. However, due to the higher solvent content in the dryers, less solvent may be removed from the printed web in these conditions. Check to see if your dryers are performing at their best.

 

Best Conditions

 

The best conditions needed for both water-based and solvent-based inks to dry are:

• ·        Warm temperatures
• ·        Low humidity
• ·        Max air circulation

 

It can be difficult to find the best combination. It may take some experimenting and troubleshooting, depending on your location, to find that magical temperature or humidity setting. The journey, however, is worthwhile in the name of high-quality printing and reduced press downtime.