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Author: Paul Kipp, Area Sales Manager, Condair Limited


Control humidity and improve productivity in digital printing

Humidity control in digital printing is essential during the cold, winter months to maintain optimum productivity. Without it internal air conditions can drop to around 25%RH. This is a long way from the typical ideal humidity level for printing facilities of 50-55%RH, as specified by paper and print machine manufacturers.

Low indoor humidity levels will impact a printer’s profits in many ways. It will detrimentally effect the performance of paper and ink as well as increase electrostatic build-up.

In low humidity environments paper loses moisture from all exposed surfaces, which are typically the edges of a reel or stack. It can change rapidly. Dimensional changes of 1-2% can occur in as little as 10 minutes. This can be visually seen in stacks of paper with tight edges causing the sheet to become concave and curl at the edges. This can lead to mis-feeds, mis-registration, doubling or wrinkling during printing.

The larger the sheet, the greater the impact of any dimensional change, so this is of particular importance for wide format printing.

Incorrect work area humidity levels will also inhibit the performance of aqueous or solvent based inks. Too dry and it will mean the solute evaporates prematurely. The ink droplet will change its viscosity impacting on its adhesion to the paper. Rapid ink drying can also block the print heads resulting in a diffused spray pattern.

Conversely, if the humidity is too high in the print room and the ink or paper pick up moisture from the air, this can lead to image smudging, as well as ink spread across the surface of the paper. This can reduce the image definition due to extended drying time.

In addition to ink and paper issues, air at low humidity increases the build-up of electrostatic. Dry air is incapable of dissipating naturally occurring electrostatic charge. It therefore becomes a much more prevalent problem in the winter, when internal humidity levels are at their lowest.

Using a properly designed and installed humidification system is the only way to ensure air humidity does not drop below that recommended by the print machine or paper manufacturer. Condair has been serving the global print industry for over 60 years. The company offers printers on-site expert assessments of their humidity management, giving advice on how best to achieve increased productivity by maintaining optimum humidity.

Get expert advice on digital printing humidity control


Get expert advice on humidity control in digital printing

Arcade

Joss Williams

Senior Project Manager

“The humidifier meets Polestar’s requirements and the customer is happy. Previous experience of Condair has been good. The guys that attended site changed the design to suit the site location with no issues in relation to price. The installation was of a high standard and looks good.”

Elopak

Jan Thidex Kristensen

Maintenance & Engineering Manager

“We can clearly see a difference in our production after we got the new humidification system. We experience less variation in our production, which means we can ensure a uniform and stable quality for our customers.

For our employees, this means a stable and healthy indoor climate independent of seasonal fluctuations in humidity and temperature.”

BluePrint AG

Gerhard Meier

Geschäftsführer

“With Condair Systems, we reliably guarantee optimum humidity, which ensures greater quality and standardisation.”

John Watson & Co

Chris Fyfe

Quality Assurance Manager

“When paper loses moisture, ink will not adhere properly, which could cause a problem for our printing company whose reputation for quality is high. Not only has the JetSpray been proven in our industry, it is also uncomplicated, energy efficient and extremely hygienic in operation.

Due to the conditions in our print room, the humidifier has been running 99% of the day since installation, keeping RH at a perfect 50%.”

Fujifilm

Steve Freeman

Jet Press Solutions Manager

“Humidity control is important for paper handling consistency when running lighter weight stock on the Jet Press 720S in both the feeder and jetting area. We aim to maintain an RH of between 40% and 60%. Below this could potentially cause an increase in paper handling issues on light weight paper.

Once the humidifier was up and running correctly, it has performed well. It now easily and quickly gets the room up to the required RH and maintains this after start-up.”

Harrier Group

Jeremy Rawley

Safety and Facilities Manager

“We already knew Condair, as we have a couple of their units in other print rooms. The quality of their equipment is right up there. Paper is susceptible to changes in environmental conditions so humidity is really important.

Their service is second to none as well. We work to tough deadlines and one of the key things for us is that Condair could supply the equipment quickly within the required timescale.

Having a local service engineer on call to maintain them in tip-top condition is important for us too.”

PODCAST: HOW TO SELECT & SIZE A HUMIDIFIER

Learn how to plan a humidification project.

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