Curl Management
Substrate conditioning techniques apply a controlled amount of moisture to the back of a sheet to counteract the tension created by printing or coating. The reverse side dampening process is used to keep the paper flat when a heavy layer of ink or varnish has been applied to the front. This prevents the edges of the sheet from rolling inward as the material dries.
Fluid Application
Mechanical systems for this task usually involve a series of rollers or spray nozzles located after the final drying station. During reverse side dampening, the moisture penetrates the fibres and causes them to expand, which balances the shrinking effect of the dry ink on the opposite side. The operator must adjust the volume of water carefully to match the coverage of the print job.
If too much water is added, the paper may become too soft or develop a curl in the opposite direction. If too little is used, the sheets will not stack properly in the delivery pile and may jam in the finishing equipment. This technique is especially useful for one-sided labels and posters that must remain perfectly flat for application.
Dimensional Stability
Maintaining the correct moisture profile ensures that the finished product performs well in the customer’s hands. Successful reverse side dampening reduces the risk of paper jams in high-speed copiers and offset presses. Proper moisture balance is the key to high-quality finishing operations.
