Unreadable barcodes can cause your business all kinds of headaches, including misplaced shipments or your products being rejected by retailers.

When printing with thermal transfer technology one simple and often overlooked method for ensuring readable barcodes is the orientation of the barcode on your product. This means choosing either a “picket fence” orientation or a “ladder” orientation. Both options have their pros and cons which we'll address for you here.

The picket fence orientation refers to barcodes where the lines of the barcode are printed in the direction the substrate travels.

The benefit of this orientation is that it results in straighter lines and crisper barcode edges as the printhead can print each line entirely in one go, allowing the printhead to heat itself evenly for a set length of time. It's important to note that to take advantage of the picket fence orientation, you must also ensure your barcodes are properly dimensioned with your printhead's native resolution. Each bar and space in your barcode must align with the pixels of your printhead or your label quality will be reduced.

The other catch to this method is that if even just one heater in the printhead burns out an entire barcode line might not be printed properly, rendering the entire barcode unreadable. This is further compounded by these print issues being very difficult to spot with the human eye. Unless they are checked by a barcode verifier before being shipped, any problems scanning the barcode are often not discovered until it's too late to correct.

The ladder orientation refers to the lines of the barcode being printed perpendicular to the direction the substrate travels in.

One of the benefits of printing with a ladder orientation is that the barcodes are still readable even if you have a faulty heater in the printhead. This will only result in a white space through the length of the barcode but this will not stop the barcode from being read by a scanner. This white space is also detectable by the human eye, making it easy to know when your printhead needs changing which can be done when convenient as the barcodes will still be readable.

There are of course trade-offs when printing with a ladder orientation. As the printhead has to turn off and on quickly to print each line individually this can result in lines that are less crisp, and for very small barcodes sometimes hard to read. This orientation can also cause increased wear to the printhead due to the rapid heating and cooling required by the printhead and is not recommended for high print speed applications.

Different thermal printhead technologies also lend themselves better to different approaches. Standard “flat head” technology, as found in most desktop label printers, is better suited to picket fence printing. Newer “near edge” technology, with its sharper printing and higher speed capabilities, lends itself better to ladder printing applications. This is especially true with automatic carton labelling where near edge technology allows high-speed direct-dispense of labels on the sides of cartons.

No matter what your application requires, get in touch with the experienced team at Reynolds Group who will help you choose the right printing technology and ensure it's set up to deliver reliable, high-quality barcodes day in day out.