Technologies for Inline Printing GS1 Digital Link Barcodes

First Published: January 16, 2024

So, your company has decided to take the plunge and move towards adopting the GS1 Digital Link barcode standard.

This will have benefits for your own company, your retail customers and the end user consumers.

This will change from the UPC barcode currently printed on your packaging or labels. While your UPCs contain static data, your new GS1 Digital Link barcodes will likely have dynamic data such as a link to product information,  the lot number, expiration date and possibly serialization, and the product GTIN. These will be 2D barcodes such as QR codes.

This means they will need to be printed very closely to the packaging time, probably right on your labeling or packaging machine.

Will Your Existing Date Coding Work for These Barcodes?

Depending on the current coding technology you use, it might.

Various types of coding systems are in everyday use today, including:

  • Continuous inkjet printers (CIJ)
  • Thermal inkjet printers (TIJ)
  • Thermal transfer overprinters (TTO)
  • High-resolution piezo inkjet printers (PIJ)
  • Laser Coders

Let’s look at these and discuss which might best meet your requirements.

Continuous Inkjet (CIJ)

Continuous Inkjet Printer by Citronix

The most common date coding technology, CIJ, is used to add variable information to packages on many packaging lines.

While, in most current date coding applications, CIJ printers are asked to print one to three lines of text, they can also print 2D barcodes if needed.

The main issue with using CIJ printers for GS1 2D barcodes is the low resolution of the printing. Most CIJ printers have a maximum print height of about 33 dots, making it challenging to produce high-density barcodes and maintain the quality score needed for GS1 compliance.

A success for CIJ printing (and other technologies) has been with 7-Eleven in Thailand, where GS1 Datamatrix barcodes are used to add the GTIN, Lot Number, and Expiration dates to food products.

See this GS1 case study: https://www.gs1.org/sites/default/files/2023-04/case-study-7-eleven-gs1-thailand.pdf

My understanding is that while 7-Eleven has had success with CIJ printing, a lot of the printing has since been migrated to other technologies.

It’s important to note that using CIJ printers requires the use of solvent-based additive (makeup) fluids, that are needed to replace solvent that evaporates from the inks during use, as well as solvents for cleaning. These fluids need to be handled and disposed of correctly according to your local regulations.

CIJ printers can be configured with environmental protection up to IP65, allowing for use in harsh environments such as those found in protein packaging lines.

Thermal Inkjet (TIJ)

Thermal Inkjet (TIJ) Printer by Videojet

Thermal inkjet printers are capable of producing extremely good print quality on many types of packaging material, making them very useful for printing 2D barcodes as well as other information.

The high-resolution printheads ensure that barcodes that meet or exceed the GS1 standard can be printed, and a wide range of inks that work well for most applications have been developed.

In addition, the relatively low capital cost and minimal maintenance generally make TIJ an attractive option for product coding. The low maintenance and enhanced uptime offset the fact that TIJ inks tend to be more expensive than inks used in other types of printing.

The main downside to TIJ printers when it comes to printing GS1 Digital Link barcodes is the fact that the maximum print height of a single printhead is 12.7 mm (1/2”).

Because the Digital Link barcodes will need a lot of information encoded, the barcode size might be too large for a single TIJ printhead.

Yes, it is possible to stitch more than one printhead output together to produce a larger image, but whether this is ideal for high-density barcodes is debatable.

For difficult environments, some TIJ printers are available in rugged versions, such as the IP printers from Markoprint. It is also possible to mount the printheads in environmental enclosures or remove them for washdown.

Thermal Transfer Overprinter (TTO)

Thermal Transfer Overprinter (TTO) by Domino

TTO printers are a good option for printing these 2D barcodes for labels and flexible packaging.

With 300 dpi print resolution and printing ribbons available that are suitable for a wide range of packaging materials, companies that already use TTO for their date coding should be able to incorporate the new barcodes quite easily.

Already commonly used for printing on labels and packaging films, TTO printers can be used on both intermittent and continuous motion packaging machines and are available with print widths of up to five inches.

For some applications, TTO printers can print additional information, such as nutritional and ingredient information.

For harsh environments, TTO printers can have a level of protection from water or dust ingress, but they would usually need to be covered or mounted in an environmental enclosure for demanding environments.

High-Resolution Piezo Inkjet Printers (PIJ)

Razr – High-Resolution Inkjet Printer by Weber Marking

A new generation of high-resolution inkjet printers has recently been introduced to the package coding market.

This class of print systems uses piezoelectric technology similar to that found in many shipping case coding printers but with a print resolution similar to thermal inkjet (TIJ) printheads.

An advantage of high-resolution PIJ printheads is that they have a higher print height than that found with TIJ, allowing them to print barcodes over 0.5 inches high with a single printhead.

An early entry in this sector is the Razr printer from Weber Marking Systems, which incorporates a 34mm high printhead with a print resolution of up to 600 dpi.

With a much larger ink capacity than thermal inkjet printers, the Razr can operate at high line speeds for extended periods, producing quality GS1 barcodes and other information on both porous and non-porous materials.

Another new solution in this category is from Markem-Imaje, the Super Piezo Inkjet system.

Introduced at Interpack in 2023, information on this concept is still somewhat sparse. The SPI promises to include algorithms that allow the printer to print 2D Digital Link barcodes onto curved surfaces without distortion.

Laser Coders

Laser Coder by Macsa ID

Laser coding technology is unique because it needs no consumables (ink or ribbon) to produce an image onto packaging materials.

As well as being able to create high-quality barcode images onto a range of materials, the fact that no solvents or other chemicals are involved makes laser coders more sustainable than other technologies. They also require minimal maintenance (mainly periodic cleaning of lenses and filter changes).

If you are considering using a laser coder, it is essential to have your vendor carry out testing to ensure compatibility and that a mark with sufficient contrast is produced.

In many cases, a CO2 laser can be used to remove a layer of ink from the package to reveal a contrasting background color below it – a process called laser ablation.

For other applications, a laser can create a high-contrast barcode directly onto packaging material; for example, a UV laser can print a dark image directly to plastics such as HDPE.

In the event that direct coding or ablation is not feasible, an additional option is to have your label or packaging producer add a laser-receptive material from Datalase to the products you buy. Datalase offers various solutions that allow lasers to produce high-quality codes in scenarios where it would not otherwise be feasible.

Finally, an important consideration with laser coding is to ensure your installation is compliant with the laser safety guarding regulations, to ensure the well being of your employees.

Conclusion

So, all of the common product coding technologies are capable of producing the 2D QR codes needed for GS1 Digital Link introduction.

Obviously, when it comes to eventually replacing your pre-printed UPC or EAN code with an online printed Digital Link barcode, you’ll need to assess whether your existing printers will allow you to produce 2D barcodes of the required quality on your packaging and what would be the best alternative technology fir you if you need to change.

If you are beginning this journey, working with one of GS1’s Solution Partners is a great way to get started.

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