The digital revolution has its sights on a new challenge, and decorating three-dimensional objects offers no shortage of puzzles or possibilities.
By Debbie Thorp
One of the often-cited benefits of inkjet is that it is a noncontact technology. Industrial inkjet printheads have been designed to print onto flat surfaces with an optimal throw distance between the printhead and substrate of less than 1 millimeter for small drops. Such small drops decelerate quickly as they travel to the surface; if the throw distance is too great, then the drops may not land in the intended place and image quality deteriorates. Larger drops can jet further (up to approximately 5 millimeters), but compromise the graphical image quality. Printers are finding they can mitigate this through careful selection of images, using inkjet to great effect to decorate objects with textured or contoured surfaces where it would have been impossible to apply a label. Krones, a major beverage machinery supplier, took this approach when they launched the Decotype R at Drinktec in 2014. At the show, they printed shampoo bottles with shaped surfaces, creating interesting visual and haptic effects that not only replaced the label, but also surpassed it with effects that would have otherwise been impossible. The technique has been widely applauded: Cycling bottles from Krones won a 2015-2016 A’Design Award, and the shampoo bottles were awarded an Oscar dell’Imballaggio by the Italian Packaging Institute in 2015.
We’re also seeing more systems that can accommodate larger or taller objects. The FJet XL from EPS, for example, can take items up to 5.9 inches high; the Azon UV Matrix can print on products up to 7.9 inches high; and Mimaki’s UJF-3024 HG (High Gap) unit can accommodate objects up to 5.9 inches high. German company Ritzi has the first installation of the Heidelberg Omnifire 1000 to decorate large automotive components, such as trim strips, switches, dashboards, and other finished components as part of their production process.
Designing inkjet systems that print well onto flat surfaces is challenging enough, requiring a multidisciplinary approach – including, but not limited to, mechanical, electrical, electronic, fluidic, and software engineering; image processing; color management; and system control. Building an inkjet system to print directly onto a bottle or tube requires all of the same disciplines, but with the added complexity of the third dimension. In order to create a good quality print, the developers must consider the curvature of the object to be printed, the orientation of the printhead, and the time of flight of each drop from each nozzle.
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