Printing Process
Rotary printing methods represent the primary industrial route for high-volume decoration of corrugated containers and flexible liners. Within this category, flexographic packaging relies on raised elastomeric or photopolymer plates to transfer fast-drying fluid inks to the moving web. The process employs a cell-patterned anilox roll to meter the ink volume before it reaches the raised image areas of the plate.
This mechanical transfer ensures that consistent ink volumes are deposited across wide webs, maintaining color uniformity over long production runs. Because the printing pressure is low, the process prevents the flute crushing that degrades the structural performance of corrugated boards.
Substrate Interaction
Surface energy governs the adhesion of liquid inks to non-porous polymer barriers and uncoated paperboards. When flexographic packaging uses water-based inks on recycled board, the absorptive nature of the fibres dictates the drying speed. Synthetic polymers require corona treatment to elevate their surface energy and prevent the wet ink from reticulating before the drying tunnel.
Press Operation
Plate mounting accuracy determines the final registration of multi-color images on high-speed lines. Modern presses run flexographic packaging at speeds exceeding three hundred metres per minute, which demands precise balance in the ink metering system. Chambered doctor blades seal the ink supply against the anilox roll to prevent foaming and evaporation of the solvents.
Maintaining stable ink viscosity during the run ensures that the density of the halftone dots remains within the specified tolerances.
