The length of dryers- function of amount of ink or coating coverage that the unit was specified to. The cover swings from the bottom easy access for roller cleaning and web threading. All gravure dryers should have some movable covers, which allow the operator to work inside the dryer. IR heater to preheat the wet inks before entering drying chamber. Excess heat- printed substrate can shrink, curl, become brittle.
Ink can skin over- trap solvent in the ink, causing odor, picking on subsequent rollers.
Heat increases the process, excessive heat- shrinkage curl, brittleness of substrate. Dryers- constructed in specific sections Zones of the drying unit. Single zone unit the temperature and air flow are same throughout the unit. Multi-zone dryers can operate independently or with air recirculation from one zone to another within the unit. Drying parameters put into formulas to predict results.