For many years multiple Coca Cola sites have relied on Domino's innovative laser coders for primary marking. The printers are used for marking PET bottles as well as the coding of bottle labels with best before dates and batch codes.
Up until now Coca Cola used ink jet printers for marking shrink wrapped packs. A KHS Kisters shrink packer cloaks 6 PET-bottles into one pack. The ink jet printers were installed at the outlet of the shrink tunnel.
In order to increase the stability of the process, the effectiveness of the wrapper marking and therefore the overall effectiveness of the shrink wrap packing; Coca Cola has decided to integrate thermal transfer printers.
Following internal project discussions, Domino advised Coca Cola to select thermal transfer overprinting technology (TTO) for the application of best before dates.
When shrink wrapped packs are marked with continuous ink jet printers, the printing system is typically located at the outlet of the shrink wrapping tunnel. The ventilators positioned here (to cool the system) can generate air turbulence. This may have a negative effect on the behavior of the ink jet system, potentially resulting in a dirty print head that reduces the print quality. In order to perform a visual inspection of the printed code, the operator must walk back and forth between the operating terminal of the shrink packer and the ink jet printer.
The TTO technology on the other hand is positioned directly behind the web cutting and spreading station. This has a positive effect, significantly improving the typeface without the risk of smudging. In addition, it has the advantage - in contrast to alternative marking processes - that the shrink packer can be stopped immediately and controlled if a code is incorrect. This prevents the time consuming, manual sorting of incorrectly coded shrink packs. This contributes to a more dynamic production line, which in turn increases the overall efficiency of the shrink wrapping process.
V320i printing onto shrink wrap packs at Coca Cola in Knetzgau
Following a successful pilot project at a facility in Fürstenfeldbruck, the Coca Cola site in Genshagen approved of the V320i purchase.
At the start of 2012, the site in Knetzgau decided to integrate two V320i thermal transfer printers to their KHS Kisters shrink packer. The shrink packer web runs at variable speeds, with two lines running at 40 to 80 sixpacks per minute. A best before date is printed on the pack.
The signal to print is triggered via a print mark detected at the fork light barrier. An additional web positioning module, including two vertically adjustable guide rollers, ensures successful marking despite variable speeds.
In order to provide operators improved access for threading in new or different shrink wrap packaging, the bracket - including the web positioning module and the V320i thermal transfer printers - is placed on a horizontal, moving sled.
The data to be printed can be entered using Domino's intuitive TouchPanel which is mounted away from the shrink wrapper. This allows the operator to easily see which print job is being processed and to visually inspect the product. This minimizes potential errors. The integrated label design software that allows for individual configuration of a print job facilitates the design of layouts on-site.