The system monitors the correct position of print on labels directly at the dispenser.
Depending on the result, there is a corresponding entry in the line-motion control which means a product which has a missing or faulty print can be automatically removed later from the line by a handling system.
Checking label accuracy
"We monitor the label and its print for correctness before the labels are distributed to the individual pack tracks of the packaging machine," said Robert Vollenkemper, sales manager, Multivac.
As an option, each pack can be checked by a luminescence sensor to see whether the label is on or under the pack.
"One camera and some luminescence sensors are less expensive and less maintenance-intensive than a camera per pack track,” he added.
“Print monitoring directly at the label dispenser already starts to pay off from two pack tracks onwards".
The company claims the system, which is available as an option for the MR600 series of Multivac cross web labellers, reduces investment costs in print monitoring.
“The investment in a print monitoring system is generally expensive,” added Vollenkemper.
“Since the packs are filled, sealed and labelled in several pack rows and tracks on a thermoforming packaging machine, automated print monitoring normally has to be performed on an individual track basis.
“This means, depending on the layout of the packaging machine, two or three or more visual monitoring systems, such as for example barcode scanners or cameras, are required for this task.
“There is a growing trend towards ever larger and wider packaging machines - and therefore towards ever more pack tracks.”
The stages of the machine are; a label strip is unwound from the roll over several deflection rollers and held taut.
A printer prints production-related data such as use-by date, barcode or batch number onto the label.
Print monitoring with an appropriate camera system takes place between the printer and the dispensing edge. After the labels have been deposited onto the packs, they are monitored to check the labels are adhered to the packs.
Fachpack 2013, is at Nuremberg, Germany from September 24-26.