JS Humidifiers is offering printers a free digital hygrometer so they can find out exactly what the humidity is around their printing presses and paper stores. Humidity in these areas should be maintained at above 50% relative humidity (%rH) to avoid paper curl, static build-up, web-breaks and mis-register.

In the colder winter months, internal humidity in printers’ facilities can be as low as 20%rH due to the fact that heating the colder air coming in from outside significantly lowers its humidity.

Once paper is exposed to dry air it will start to lose its moisture content. When it is stored on reels or in stacks the outside edges will be exposed to dry air and therefore a have different moisture content to the middle of the sheet. This causes the paper to curl at the edges which can lead to problems with feeding on the press.

Problems with mis-register can occur if the moisture content of the paper changes between multi-pass print jobs. This will cause the paper to physically change shape resulting in misalignment with pervious print runs. Issues with static can occur when the humidity drops below 40%rH. If the humidity is maintained at above 50%rH static build-up is totally eliminated.

Any printer suffering these problems should measure their humidity to see if a dry environment is the cause. The free digital hygrometer from JS Humidifiers shows current humidity and temperature and can display minimum and maximum levels across any time period with its memory feature.

Printers wishing to be sent a free hygrometer should email sales@jshumidifiers.com with their name and address or simply call JS on 01903 850200.

JS Humidifiers is the UK’s largest humidification company and has been humidifying the printing industry worldwide for over 25 years.

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