Blow Molding: Digital Inkjet Printing onto PET Bottles
Printing directly on bottles can substitute for labels and in some cases can take place inside the blow molder.
Digital inkjet printing directly onto PET bottles—in place of labels—made a vivid appearance at K 2019 in Düsseldorf in October (see show report in January issue). Krones showed printing of sophisticated graphics on PET bottles, followed by UV curing (below, left). Atmospheric plasma pretreatment prepares the bottles for printing. Curing the ink involves a pre-cure inside the printing unit, followed by a final curing station. Called DecoType Lab, this printing technology comes from Dekron GmbH, a new Krones subsidiary.
Digital inkjet printing directly on PET bottles: Krones (left), 1Blow (right).
A second example at the show was 1Blow of France. Despite the unusual compactness of its two-stage (reheat) stretch-blow machine, there is room to perform inkjet printing inside the machine. An example (above, right) is a PET honey bottle shaped like a bear, with inkjet-printed eyes and nose.
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Applying a static charge to hold the label in the injection mold eliminates the need for vacuum ports that addsignificantly to the cost of making and maintaining the tool.