Printers of official documents are always innovating to remain one step ahead of counterfeiters and forgers. A national bank for an OECD country wanted to include a new security feature, optically variable film, on each of the bank notes it printed. The challenge was to develop a process for applying a very thin and delicate film to bank notes of various sizes and paper weights at a high rate with minimal rejects due to quality.
We developed a new process to apply a film of holographic material to a web of bank notes. The process precisely placed each optically variable element on the bank note without damaging the essential, difficult to replicate, properties of the film. A thin web of material was applied to sheets of bank notes, both travelling at different rates through the machine. The bank notes were a pre-cut printed web, small variations in sheet feeding meant that the film needed the ability to be repositioned after every application. A new and novel vacuum accumulator was used so that optically variable film could be positioned precisely with the bank notes using servo-driven rollers.
The new machine was able to operate at 8,000 sheets of bank notes per hour, rivalling contemporary machines with less intricate security features. The film was applied to an area of 12.5mm x 11.0mm with a border tolerance of only 0.33mm. For such a delicate operation, the machine operated with a very high yield, producing 99.94% quality notes for every one processed. The machine provided the most cost-effective means of applying optically variable security film to bank notes, protecting Canada’s currency from counterfeiting.