Inkjet & Digital Printing

Quantum leap for coin printing

Thursday 25. February 2021 - The colouring of coins and other precious metals is a growth market - all the more important is an efficient, economical printing process. THIEME now provides a quantum leap in efficiency with a new type of digital coin printer:

With this system, which is unique on the market, more than 600 coins per hour can be printed in multiple colours for the first time in a largely automated, highly productive printing process.
Coloured coins, where parts of the minted motif are coloured, are real “eye-catchers” and are therefore becoming increasingly popular, not only among collectors. At the same time, the colour application brings additional variety to the otherwise limited design spectrum in coinage, so that almost all official mints now offer coloured coins. For a perfect printing result on the three-dimensionally minted reliefs, it is crucial that the coin blanks are precisely aligned before printing; moreover, the ink application must be so stable that the coloured coins survive the final rolling process undamaged.
Up to now, mainly screen printing or pad printing processes have been used for printing coins and other precious metals. In cooperation with a German mint, Thieme has now developed a new type of digital coin printer that considerably speeds up the printing process. The inkjet printing system, which is unique on the market, works with tested special inks that guarantee optimum adhesion and abrasion resistance of the ink application on the metal substrates. The system offers a total of seven colour channels (CMYK, white as well as primer and topcoat); a fluorescent clearcoat is also available for special lighting effects.
Efficient loading, automatic alignment
A high degree of automation and easy loading are essential for an economical printing process. The Thieme coin printer operates according to a completely new concept with exchangeable adapter plates (trays) in which a large number of coins or ingots can be loaded simultaneously. The double table system allows parallel loading/unloading and printing with a cycle time of approx. 180 seconds per tray. When 32 coins are loaded, this means a throughput of 640 coins per hour.
Another efficiency boost is provided by the innovative, automatic alignment system: thanks to Digital Image Alignment, the blanks can be inserted into the press in any position – the stored print layout is automatically adjusted to the angular position of each individual coin using a scanning process. The digital alignment takes only one to two seconds at a time and is thus significantly faster than the mechanical positioning of the coin receptacle in classic printing processes. “In this way we achieve a multiple of the previously possible throughput,” explains Oliver Beck, Sales Manager Printing Systems at Thieme. The innovative system is also unbeatable in terms of printing costs, he adds: “The ink costs per 32-millimetre coin are less than one euro cent.”
High print quality and productivity
The higher productivity does not come at the expense of print quality: with the print resolution of 800 x 1200 dpi, even very filigree embossing motifs can be coloured with high quality. The automatic alignment is also very precise with a repeat accuracy in the range of ± 0.1 mm. “Our new inkjet printing system revolutionises the previous process of coin colouring,” promises Oliver Beck. “In the future, the previously rather laborious printing process can be carried out much more efficiently, flexibly and at the same time in the highest quality.” In times of increasing demand, this gain in efficiency is crucial: “For the mints, this is a real quantum leap.”

www.thieme.eu
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