Humidity Control Vital To Print And Paper Quality

J S Humidifiers is offering printers a digital hygrometer so they can find out exactly what the humidity is around their printing presses and paper stores.

The company said that humidity in those areas should be maintained at above 50 per cent relative humidity to avoid paper curl, static build-up, web-breaks and misregister.

In cold winter months, the internal humidity in printers' facilities can be as low as 20 per cent relative humidity because heating cold air coming in from outside lowers its humidity.

Once paper is exposed to dry air it will start to lose its moisture content, added J S Humidifiers, and when it is stored on reels or in stacks the outside edges will be exposed to dry air and, therefore, have a different moisture content compared to the middle of the sheet.

That causes the paper to curl at the edges, which can lead to problems with feeding on the press.

The company also explained that problems with mis-register can occur if the moisture content of the paper changes between multi-pass print jobs.

That will cause the paper to change shape, resulting in misalignment with previous print runs.

Issues with static electricity can occur when the humidity drops below 40 per cent relative humidity and if that is maintained at above 50 per cent static build-up is eliminated.

J S Humidifiers added that any printer suffering such problems should measure their humidity to see if a dry environment is the cause.

The company's free digital hygrometer is said to show current humidity and temperature and can display minimum and maximum levels across any time period with its memory feature.

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