Did you know that one ton of paper (appr. 2000 lbs) may contain up to 100 litres (appr. 26,5 gallons) of water? Paper is a natural substance which may absorb water and also release it. Quite a number of binderies and bindery departments have experienced that...
During printing and further processing under the worst conditions a sheet may shrink or stretch by milimetres. For that reason air conditioning is not only essential in the press-room but in the whole plant. If the paper is processed outside of the printing shop you still need a uniform humidity.
Here are a few hints on how to avoid register deviations, doubling, wrinkling and cutting differences when handling paper:
- Have the paper delivered ahead of processing in order to have it acclimatised to the temperature and humidity in your plant. Optimalvalues of humidity: uncoated paper 45-50%, coated paper 50-55% and cardboard 55-60%. Acclimatisations time 2 to 3 days.
- Dry paper tends to develop a lot of dust.
- Avoid processing paper which has the grain running in different directions in the same pile.
- Consider appropiate wrapping. Picture 1 shows a wavy pile as the cover is not rigid enough and the bands have been tightened too much.
- Use correct size palettes. Even when storing the piles for a short time, the palettes have to be big enough. Picture 2 shows how the pile distorts on a small palette.
- Never store paper next to open doors and never expose it to direct sunlight (Picture 3).
- The reams should always be stacked correctly and neatly and not as shown as in picture 4.