Hot Effects with Cold Foiling Technology

(NPES International E-commerce Website, August 12, 2008) Cold failing technology is a further option for combining processes and pursuing inline finishing that has been developed by the manufacturers. Foil transfer itself requires two printing units. In the first a special adhesive delivered by the Ink unit is transferred to the substrate with the resolution and fineness of detail of an offset plate. In the following unit the foil is transferred to the partially adhesive coated substrate. The portion of the foil that is not transferred is rewound with the carder layer.

MAN Roland presses for example feature two additional towers. These can be positioned on any two adjacent printing units and they allow a torsion free foil path. By placing the foil rewind and unwind elements in two separate towers the stresses are evenly distributed and a single tower is not subjected to excessive stress.

The high resolution that is possible with cold foil transfer opens up new design possibilities in relation to type and fine details. The letterpress forme required far classic hot foil stamping immediately means that the system is capable of resolving less detail. Compared with the inline cold transfer process, offline hot foil stamping offers less accurate register. An inline foiler that is integrated into the printing process delivers an accuracy of register that matches that of offset printing.

One major advantage of cold foil transfer over offline hot foil stamping that is worth stressing is the ability to overprint it. Unlike hot foil stamping, the transferred foil lies fiat on the substrate and it can therefore be printed immediately after transfer without any problem.

The combination of cold foil transfer with subsequent overprinting opens up many new design possibilities and this possibility also means that the acquisition and storage costs associated with the process are lower; a particularly important combination of plus points in the highly competitive printing industry. In classic hot foil stamping a foil generally consists of a carrier material to which a transfer layer which is in fact usually double- layered is applied. The situation is quite different for the user of an inline foiler, since the ability to overprint the foil means that nearly any color tone can subsequently be achieved and creativity knows no bounds.

Cold foil transfer means that one is no longer tied to predefined color tones and it is even possible to print entire images on the foiled elements. Effects of this kind are closed off to the hot foil user because in hot foil stamping it is very difficult to overprint the stamped foils - and in any event this is usually carried out through an additional, second printing pass. The subsequent overprinting also improves the adhesion to the substrate of cold-foiled foils. Transfer foils can be overprinted with conventional, UV or hybrid inks.

The third dimension
Help is on the way for users of hot foil stamping, who frequently continue to lament the lack of the third dimension in the cold foil transfer process. MAN Roland is currently working with partners from the supply industry on the development of a stamping process that will deliver a stamped, cold-foiled transfer that is rich in detail. Although the process is still under development, it is already showing great potential in terms of improvements in change-over times and quality. In future, this process should allow flat foils to take on a new, third dimension on the printed sheet through a stamped structure. MAN Roland has applied for a patent for this combination of processes, which it refers to as 'cold foil transfer and 3D stamping in one'.