The ELMC10 humidity system at VGL

Having installed a new HP Indigo press, Berkshire print company VGL needed to ensure a stable environment for the press to operate in. Humidity Solutions stepped in.

There are very clear and well-documented benefits to maintaining effective humidity control within a print environment. Dry air can cause paper curl, web breaks and static build up; issues that are ever more regular in the winter months. When spooling the paper, printing presses may generate electrostatic charges, and this can then mean that the pages become hard to seperate.

The optimum humidity for printing and paper storage conditions should be between 50-60% relative humidity (RH – the amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature). Issues that can occur if the relative humidity is not at this level include mis-feeds and creasing, and transformation of paper sizes, in turn affecting registration.

Once a humidity solution has been applied, the separation of sheets of paper is improved, paper curl is avoided and productivity increases. The machinery will be able to work at a higher speed as the feed will be more efficient with less paper rejected. It also helps to ensure that the product remains in prime condition.

Low humidity (below 30% RH) can have a negative impact on the health of the workforce and, therefore, on productivity. It is for these reasons that the majority of print companies engage with humidity control specialists to ensure they have the right humidity solution, delivered in the most cost-effective way.

 

One such case has been digital print specialist VGL, which has deployed a humidity control solution for a new HP Indigo 5600 digital printer at its facility in Reading. The system was designed, supplied, installed and commissioned by Humidity Solutions and comprises two ELMC10 electrode boiler humidifiers to maintain the precise and stable humidity control required.

Established since 1976, VGL is a family-run company with a strong track record for investing in the latest print technologies to ensure it is offering its customers the best print quality and service. ‘We recently upgraded to the HP 5600, which is considerably faster than the previous printer we were using,’ VGL’s Russell Fry explained. ‘However, to maintain the required throughput reliably we needed to ensure the relative humidity was stable.

‘We spoke to a number of humidity specialists and it was clear that Humidity Solutions had the best understanding of what our business required, as well as the technical requirements for the printer.’

The two ELMC10 humidifiers are fitted with direct air ventilation units to distribute water vapour directly into the space, and are positioned at high level to ensure efficient distribution with no wetting of machinery. The units have been sized to allow for 12 air changes per hour and achieve a minimum of 50% RH and maximum of 70% RH (non-condensing) at 20-25°C.

In maintaining a stable humidity, the units are ensuring the printed products are of high quality while also eliminating static electricity.

John Barker, sales director at Humidity Solutions, told Digital Printer: ‘The VGL site was not an unusual application. The area where the digital printer is installed needs to be climatically controlled to remove the high heat gains generated by the press. Most people think that climatic control is just regulating the temperature but this is a misunderstanding and can lead to other issues for the press – namely low humidity.

‘In the UK, the natural ambient moisture content is low when the air is brought into our press rooms and heated up due to factory heating or heat given off by the presses. If you then try to reduce this temperature by introducing air conditioning, this process then removes even more moisture from the air, resulting in humidity commonly as low as  20-30% RH. This causes major issues with digital presses and puts them outside of the manufacturers’ stated environmental conditions, so reducing the efficiency of the press, reducing print quality, slowing machine speeds and invalidating warranties from the manufacturers on certain components.

‘Humidity Solutions have installed many systems in digital print, litho, large format, web and gravure printing to create a stable condition for the paper and repeatable conditions for the press, thereby removing one of the printer’s many variables.’