Dry air in the printing industry 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, 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% RH. Issues that can occur if the relative humidity is not at the correct level include:
– Paper can be misfed and creasing may occur, as in dry conditions moisture is drawn from the exposed surfaces of the stacks of paper. This means that tight edges can occur as the exposed edges shrink.
– Paper sizes can also transform and this would in turn affect how the colours line up in printing runs of two or more colour processes.
Once the 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 as less paper will be rejected.