The challenge

• Double-sided printing on pallets
• Labelling of pallets in continuous operation
• Ambient temperature from minus 5 to minus 23 degrees
• Label printing in plain text and machine-readable in the form of a Code 128 barcode.

The result

• 20 pallets per hour in teamwork
• Printing of QR codes with a resolution of up to 600 dpi
• In addition to high-speed printing, the system can also label at lightning speed
• It applies up to 80 labels per minute to product surfaces

‘In more than 150 years, a small consumer cooperative has grown into an international company in retail, wholesale and production,’ explains Mahendran Neshanth, maintenance planner for technology at Coop in Schafisheim. The Coop Group employs around 95,000 people. Schafisheim is home not only to the Coop bakery, but also to a distribution centre for frozen products. Around 200 pallets full of goods are delivered to Coop stores every day from the local high-bay warehouse alone.

Double-sided pallet labelling

‘Our pallets must be reliably labelled with all relevant information,’ explains Nebojsa Vasic, Logistics Group Manager. ’That's why we label them on both sides with the SSCC, best-before date, recipient, sender, ramp number, tour number and total weight.’ In addition to plain text, most of the information is also encoded in machine-readable form as a Code 128 barcode and printed on the labels. Part of this 18-digit code is the SSCC – Serial Shipping Container Code. This information enables the pallets to be labelled in accordance with GS1 standards and uniquely identified worldwide. The SSCC is also suitable for intralogistics purposes. It helps with internal pallet management.

To do this, Coop uses two Legi-Air 4050 P pallet labellers from Bluhm Weber Group. In Schafisheim, they work in tandem to label around 20 pallets per hour simultaneously on the front and back. In terms of labelling speed, the Legi-Air 4050 P is entirely dependent on the conveyor belt speed. At peak performance, it can label up to 240 pallets per hour on both sides. That corresponds to four pallets per minute. The pallets do not have to stop for this. Labelling takes place in a continuous process.

To ensure that each pallet is labelled with the correct data, Coop's ERP system sends the individual print information to the print modules installed in the labellers. They print the data in plain text and as SSCC barcodes on the pallet labels and feed them to the respective dispensing stamps. Once the corresponding pallet is in position, the stamps extend and label the passing pallet on the front and back. The pallet then continues on to dispatch.

The Legi-Air 4050 P is equipped with numerous safety features. If, for example, there were a power failure during the labelling process, a pallet weighing several hundred kilograms would continue to roll slowly, damaging the extended applicator. The swivel arm of the Legi-Air 4050 P is therefore designed in such a way that a passing pallet would not damage it, but simply push it to the side. This technology has been patented by Bluhm Weber Group.

Product marking with QR code

The national distribution centre for frozen products has ambient temperatures ranging from minus 5 to minus 23 degrees Celsius. The frozen products are also labelled fully automatically. Four Legi-Air 4050 E label dispensers mark the cardboard boxes with a QR code. As the packaged products pass the labeller on the conveyor belt, the print module prints the label, the dispensing stamp dips down and blows the shipping label onto the cardboard box without touching it. A sensor on the stamp plate detects the respective surface and stops the applicator a few millimetres away. The large label supply roll of up to 450 running metres ensures high availability.

The Legi-Air 4050 E is designed for continuous operation and is therefore particularly suitable for labelling shipping units such as cartons or pallets. The system can control print modules from all leading manufacturers and thus print labels with a resolution of up to 600 dpi. High resolution is important to ensure that QR codes can be read automatically.

A Zebra print module has been integrated at Coop, which can print labels at a speed of more than six millimetres per second. In addition to its rapid printing, the system can also label at lightning speed: it can apply up to 80 labels per minute to product surfaces.

Film printing in Switzerland's largest bakery

Coop operates Switzerland's largest bakery at its Schafisheim site. Marking technology from Bluhm Weber Group is also used here. A Linx continuous inkjet printer marks the film used to wrap the baked goods with an SSCC number in alphanumeric form. The printer not only has to cope with temperature fluctuations, but also achieve an abrasion-resistant print result on the smooth film while ensuring that the marking is food-safe. ‘The print may come into contact with the baked goods, so it must of course be completely food-safe,’ explains Thomas Stöhr, UHB Technical Mechanic.

Inks that could come into contact with food must not contain any ingredients that are on the so-called raw material rejection list. Therefore, each individual ink composition must be tested by independent institutes and laboratories and declared safe. The food-safe inks used in Linx continuous inkjet printing systems contain only EU-approved food additives and colours and are therefore considered safe.

The Linx continuous inkjet printer uses a food-safe ink mixed with solvent. This mixture has the advantage that the ink adheres reliably to the smooth surface immediately. The printhead of the marking device is mounted directly in the packaging machine. This means that the films are marked automatically as they move past the conveyor belt in the unsealed cardboard boxes.

The Linx is renowned for its production reliability. The device not only continuously monitors the ink and solvent levels, but also constantly determines the viscosity of the ink in order to automatically adjust it to the ambient temperature. In addition, excess pressure in the printhead housing prevents moisture from entering.