Surface Transfer
Relief printing plates transfer fluid inks onto corrugated and folding boxboards through mechanical pressure. Flexographic printability dictates the degree of success for this ink delivery on porous cellulose substrates. Surface smoothness and local compressibility determine how uniformly a photopolymer plate deposits low viscosity inks across a corrugated linerboard or folding carton surface.
Plate relief depth prevents background fouling while dot gain control preserves image fidelity during high speed converting operations.
Ink Chemistry
Low viscosity solvent, water, or ultraviolet curable formulations dictate drying rates and final bond strengths on paperboard surfaces. Pigment concentration and resin ratios govern transfer efficiency and trap characteristics during multi station printing passes. Solvent retention limits must balance against drying tunnel temperatures to avoid blistering or substrate distortion on lightweight liners.
Viscosity drift during long press runs alters dot sharpness and demands continuous monitoring of fluid rheology to maintain visual consistency.
Substrate Interaction
Cellulose fiber orientation and surface sizing agents regulate fluid absorption rates and final ink penetration depths. Excessive porosity causes lateral wicking of liquid vehicles, which reduces optical density and blurs fine text elements on unbleached kraft papers. Controlled surface tension ensures adequate wetting by aqueous formulations without requiring excessive thermal energy from dryer sections.
Coating pick resistance prevents fiber lifting during high speed separation of the plate from the substrate.
