Improve print productivity with optimum humidity! In the extremely competitive print market, humidity control is essential to maintain productivity at all stages of production and avoid machine downtime and waste.
Paper loses moisture rapidly when exposed to dry air. Sheet and web roll paper is typically produced and wrapped to stay in equilibrium with air at a humidity of 50±5%RH. When the ambient humidity falls below this level, paper loses water to the environment from exposed surfaces, changing its shape, dimensions and physical properties.
Below 40%RH, the movement of paper on paper and other surfaces generates electrostatic charges, which cause it to stick together, attract dust and become difficult to handle.
Sheet Fed Offset
Unwrapped paper in a dry press hall will lose moisture from any exposed surface. Tight edges result, making the paper curl, causing misfeed, misregister, dot doubling and creasing as the paper passes between blanket and impression cylinders. Misfeed also occurs due to electrostatic build-up, making stacking difficult. Printed work awaiting another pass continues to change shape, resulting in misregister.
During finishing, paper that has low moisture content will crack along folds resulting in a lesser quality product or increased wastage. Maintaining a relative humidity of 50-55%RH in the press hall and bindery resolves these issues.