Question to Ask when Labeling a Carton using a Label Printer Applicator

When deciding to label a carton on a new or existing conveyor line there are several things to take into consideration. Where the label is to be applied on the product, line speed, product handling and environment are just a few.

For this paper we will be discussing using a Label Printer Applicator to label a carton on a production line. The basic label printer applicator (LPA) consists of a print engine, a label application module, label unwind and label rewind.

Label formats and data are sent to the print engine from a host PC or other input device to print on the label. There are many off the shelf label creation packages to choose from to create these label formats. Using a PC the label generation software allows for the design of a label, saving the label and sending it to the print engine.

When triggered the printer prints on the label material using either direct thermal technology or using thermal transfer ribbon. Sato, Zebra and DataMax are a few of the top selling print engines to consider. All the print engines mount on the base plate of the applicator the exact same way, using only five bolts.

The first question to ask is where the label is to be applied on the product. Will it be on the side, top, leading panel, trailing panel, around the corner or on two adjacent panels?

Side Apply or Top Apply Labeling

Side Apply:  Label is applied on the same side of the product as the applicator is mounted.

Top Apply:  The applicator is suspended over the conveyor and applies the label to the top of the product.

Application Cycle

  • product enters the labeling station from a customer supplied source
  • a label is dispensed onto a Delrin tamp-jet pad
  • product is detected with a photo cell
  • at a specified time, determined by the photo cell: the tamp cylinder extends towards the product’s presented panel
  • as the tamp pad comes into contact with the product, the label is pressed onto the panel
  • a blast of air is expelled through the tamp pad to ensure the label adheres to the carton
  • tamp pad returns to the home position, ready to receive another label

The label is delivered to the side panel/top panel by means of a vacuum tamp pad mounted on the end of an air cylinder. The distance from the LPA to the conveyor and the placement of the product on the conveyor determine the required stroke length of the air cylinder. The preferred method is to have the product justified to the labeling side of the conveyor. This keeps the labeling surface in the same location, every time.

Label placement is affected by the line speed and distance to the carton from the applicator. It is best to have the applicator as close to the labeling surface as possible for optimum throughput. The product detector sees the product, sends a signal to the printer applicator to fire. Delays can be introduced to affect the amount of time after triggering before the cylinder is extended, thus fine tuning label placement.

If the distance between the product and applicator varies, a sensor can be mounted to the tamp pad. The sensor can be a close proximity detector or a mechanical switch that is activated by compression. This “smart tamp” then allows the air cylinder to stroke out and stop at the surface of a product that is not a consistent distance from the applicator. It is set to apply the label at the moment it finds the surface and then stop the forward momentum and retract.

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