Buying a used offset press with inline coating? The spec sheet usually says only with coating unit — yet that can mean a plain water-based coater on one machine, or a double coater with UV end-of-press drying on another. The jobs it can take, and the price, differ by more than a factor of two. The global market for offset UV dryers is worth about USD 1.007 billion in 2026, growing at roughly 8.81% a year, with demand coming almost entirely from packaging and commercial work — which is why presses with a complete drying package carry a clear premium second-hand.
- Choose the coating chemistry from the job mix: water-based for protection, UV for high-end packaging, hybrid inks only with dual-purpose rollers and blankets.
- Count the inter-deck drying stages and note their position — short-wave 1.2 µm pre-drying and medium-wave carbon 2.5 µm inter-deck drying are separate modules.
- UV coating is never complete without an end-of-press dryer; two inter-deck UV units after the last printing unit are recommended.
- Check whether the delivery is extended or compact — its length governs film formation and top speed.
1. Identify which coater is actually fitted
Three configurations dominate: a single water-based coater applies protective coating only; a UV coater delivers high gloss and special effects; a double coater — primer plus finish — does both in one pass. Metallic, pearlescent, gold and silver effects, or coatings that foam easily, call for a flexo module ahead of the printing units, which handles substrates from onion-skin paper up to 1 mm board and can lay down opaque white before the offset units. For presses of similar age and format, the coater typically adds more than 20% to the asking price.
2. Inter-deck drying is the real dividing line
Whether coating actually runs comes down to drying. A mature double-coater line has four stages: a pre-drying module below the walkway after the last printing unit fitted with a short-wave 1.2 µm infrared dryer; an inter-deck dryer behind the coater carrying a medium-wave carbon 2.5 µm infrared emitter; an intermediate drying station; and a further inter-deck dryer under the walkway. At the delivery, combined systems supply hot air plus infrared at about 62 W/cm, with water-cooled sheet guide plates holding sheet temperature in check. At inspection, power every stage: modules should be plug-in cassettes with intact quick locks, and lamps and reflectors free of blackening — replacing dead lamps costs far more than the discount won at the table.
3. UV coating also needs the right rollers, blankets and final cure
Hybrid ink blends conventional and UV ink, so it requires dual-purpose rollers and blankets. The UV inter-deck dryer belongs immediately after the last printing unit — two units are recommended where possible — and the end-of-press dryer is not optional. Heavy solids are the classic weak spot: a 400% black field coated directly tends to lose adhesion, so a primer goes down first and the UV finish coat on top. A press badged for UV but running standard rubber rollers with no final dryer will rework packaging jobs again and again.
4. Three hard checks before you sign
Fire every infrared and UV stage individually and log current draw and warm-up time — one missing stage breaks the chain. Match the drying modules to the delivery: extended delivery suits heavy board, compact delivery suits thin-paper short runs. Run a genuine coated job and look for set-off, orange peel and uneven gloss; those three symptoms expose lamp ageing and a wrong coating weight faster than any spec sheet.
Conclusion: Judge coating and drying as a chain — number of coating decks, number and wavelength of the drying stages, roller and blanket compatibility, and delivery-end drying capacity. Miss one link and the press loses much of its high-end packaging capability, and that missing link is exactly where the bargaining room is.
