Barcode printers and labels - a basic guide
Updated: Aug 3, 2021
Commonly used barcode printing options for retail, industrial and asset tracking.
Barcode label printers
Barcode printers are used for producing self-adhesive UPC-A or EAN-13 barcode labels which can be applied directly to your product ready for retail. They are especially useful in cases where your packaging has already been printed without an embedded barcode or if your product comes in a transparent plastic wrapping. If you produce many products which require labels it may make financial sense to invest in your own printer, which can also be used in an internal barcoding system to track and trace cartons, boxes or pallets for shipment. Barcode printers are also widely used for asset tracking systems such as warehousing or storage facilities.
A computer peripheral device, barcode printers require software (often included by the manufacturer in the printer purchase) for the design and alignment of the label size and the transfer this data to the printer. Fast industrial printers, with large paper capacities, are generally used in factories and warehouses whereas smaller desktop printers are utilised in the retail sector. Small portable units are available for creating asset tracking labels. Label printers were originally prohibitively expensive and could only be utilised by very large retail chains, today however, thanks to advances in microelectronic technologies, they have become increasingly more affordable.
The two most common type of barcode printers are ‘thermal transfer’ printers and ‘direct thermal’ printers.
Thermal transfer printers
Thermal transfer printers use a thermal print head to transfer a solid ink image from a ribbon onto a label. The ribbon is usually made from wax, resin, or a combination of the two, depending on the type of labelling material required and the application for which the labels are to be used and bonded to the label surface with heat and pressure. The majority of ribbons are black but are also available in colour.
The thermal transfer ribbon cannot be reused, however the print quality is higher than the direct thermal method. The resulting labels remain readable and scannable for an extended period of time and are therefore ideal for retail barcode labelling. Since thermal transfer printers require ribbon, supply costs are higher than direct thermal printing methods however, thermal transfer printheads last longer than direct thermal printheads.
Thermal transfer printing produces consistent, reliable printing on every label.
Direct thermal printers
Direct thermal printers use chemically-treated paper that darkens when heated by a thermal print head. Although generally less expensive than thermal transfer printers, sunlight, display lighting, chemical vapours or other catalysts may cause the label to fade over time rendering it illegible. Direct thermal printers are therefore generally recommended for use on labels that are only to be used for a short period time, such as barcoded tickets, shipping labels, patient and visitor identification tags and receipts, whereas barcode labels for retail products, with a shelf life of a week or longer, should be printed with a thermal transfer barcode printer.
The printhead comes into direct contact with the label material causing it to be worn out faster than in thermal transfer methods where the smoothness of the ribbon protects it. In terms of cost this may be a consideration, although with recyclable materials available, direct thermal printers have economical and environmental benefits.
Thermal label printers are therefore ideal for barcode printing as they produce accurate, high-quality images with excellent edge definition. They are are designed to print within narrow tolerances and to produce the exact bar widths required in successful barcode printing and scanning.
DPI (Dots Per Inch)
Different makes of barcode label printers have varying DPI values which range from 152 to 600 DPI and correspond directly to the number of tiny heating elements found on the printhead of the machine.
For barcode label printing, a DPI of 300 is recommended although the size of the labels will also influence which DPI can be used. If the original barcode image is increased in size then 152 or 203 DPI may be sufficient, and a 600 DPI printer can be used to print barcodes which are smaller than the original size. Therefore a barcode which is one inch (2.54 cm) wide and scannable when printed on a 200 DPI printer could be reduced to a third of an inch (0.85cm) wide when printed with a 600 DPI printer.
It's important to remember when resizing a barcode that the dimensions of the barcode need to be scaled up or down proportionately in order for the barcode to remain readable. See our handy guide https://www.barcodeireland.ie/dimensions-and-sizing
Higher resolution DPI printers are obviously more expensive and hence consideration should be given to the available space for the label on your product. If you have a large amount of space available and can therefore print larger sized labels, a 200 DPI printer may be sufficient.
Also, consider if you want to include an image such as your logo, or additional text such as product details or contact details. High resolution printers are capable of producing 2D barcodes such as QR codes or data matrix barcodes and using their coloured thermal ribbon, you can create your very own product label - including image and text!
It is important to choose the correct substrate on which to print your barcodes. Labels come in an array of materials from ordinary paper, to polypropylene, to polyester the choice of which is dependent on the environment in which it will be scanned. The differing label materials will require a corresponding thermal ribbon.
These are the most widely used, least expensive, easy to apply barcode labels that are printed with a wax ribbon - although direct thermal options are available. The vast majority of retail products can be barcoded with these standard semi-gloss labels, except in high moisture environments or high wear and tear areas. They are available in an large array of sizes and colours, the standard being either 40mm x 30mm or 30mm x 20mm.
These plastic based labels are suitable for environments where your product may be exposed to water or wear and tear, for example, the refrigerated and frozen food industries and pharmaceuticals. They are especially useful for asset tracking due to their longevity, oil and alcohol resistance and are only marginally more expensive than paper labels. These labels need to be printed using a wax resin combination ribbon but are also available in thermal varieties.
A significant advantage of these labels is that they are recyclable.
Polyimide is a plastic material designed specifically for long-term durability in temperatures in excess of 250°C. Thermally very stable and particularly useful in the electronic field.
Incredibly durable, these labels are advised for harsh outdoor environments where products will be exposed to UV light, heat, chemical or corrosive elements. Because of their durability they are a much more expensive option which generally can only be printed with a thermal transfer printer using a resin ribbon.
Polyethylene is water and chemical resistant and a less rigid material than polyester, ideal for use on curved surfaces such as bottles.
There are many other materials onto which barcodes can be printed such as aluminium, teflon and stainless steel. Aluminium is exceptionally useful in tracking high value assets as the barcode tag is virtually impossible to remove without destroying the label or the underlying surface. These tags are extremely strong and will remain legible and attached to the item for its lifetime. Alternatively, Vinyl labels combined with a strong adhesive are particularly tamper-resistant, shattering into small pieces if removal is attempted.
Our barcodes work internationally. Should you require barcodes for your product, please visit our Buy page www.barcodeireland.ie/buy, or contact us on email@example.com or through the contact form on our website www.barcodeireland.ie/contact and let Barcode Ireland help your business.