In this article we aim to give you a basic understanding of the more commonly used barcode label printing options available for retail, industrial and asset tracking purposes. We cover the pros and cons between direct thermal printing versus thermal transfer printers, and what label material you should use for their varying applications.
Barcode printers are used for producing self-adhesive labels or stickers which can be applied directly to the product which you need to sell. They are useful in cases where your packaging has already been printed without including a barcode or if your product comes in a transparent wrapping such as clear plastic. If you produce a large amount of products which need labels it may make financial sense to invest in a printer of your own, especially if you also make use of 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 in the case of libraries, blood banks and large warehousing or storage facilities.
A barcode printer is a computer peripheral device, and will therefore require that you install the appropriate software for the design and alignment of the label size you have chosen, and to transfer this data to the printer itself. Very fast industrial printers are available for use in factories and warehouses whereas desktop printers are utilised in the retail sector. There are even small portable units available for creating asset tracking labels. Originally of course label printers were incredibly expensive and could only be utilised by very large retail chains, but thanks to dramatic improvements in microelectronic technologies, they became vastly cheaper in exactly the same way that desktop inkjet printers did. Most companies will include the software which you require with the printer when you purchase it, although for very large businesses where networking is required you may need to invest in a more elaborate system.
The most common type of barcode printers are ‘thermal transfer’ printers and ‘direct thermal’ printers. The thermal transfer method involves a printhead which generates sufficient heat to melt a wax or resin (or combination) ribbon which runs in tandem with the label material itself, transferring the ink contained in the carbon ribbon to the paper or other substrate to create the barcode image and text. There are various types of ribbon available, some even in colour – although the majority of course are black. The pigment mixes available are either wax or resin based, or a wax-resin combination, depending on the type of labelling material required and the application for which the labels or tags are to be used. The thermal transfer ribbon cannot be reused, however the print quality is higher and the labels will remain readable and scannable for a considerable time. They are therefore ideal for retail barcode labelling.
In the direct thermal process heat is also generated, but causes a chemical reaction with the impregnated thermosensitive coating of the label material itself, turning the heated area black in a process very similar to the original fax machines and today’s retail receipt printers. These direct thermal printers are generally less costly, but involve the risk of external factors such as sunlight, display lighting or chemical vapours rendering the label illegible, and they will fade and yellow over time. Direct thermal printers are therefore generally recommended for use on labels that are only to be used for a short period, such as barcoded visitor passes or tickets, whereas barcodes for a retail product with a shelf life of around a week or more should be printed via a thermal transfer barcode printer. Because the printhead comes into direct contact with the label material this does also tend to cause the printhead to be worn out faster than in thermal transfer methods where the smoothness of the ribbon protects it.
DPI (Dots per Inch):
Different makes of barcode label printers have varying DPI values, ranging from 152 to 600 DPI. This number corresponds 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, however, the size of the labels themselves also influences 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. For example, a barcode which is one inch wide and scannable when printed on a 200 DPI printer could be reduced to a third of an inch wide when printed with a 600 DPI printer. Remember when resizing a barcode that the dimensions of the code need to be scaled up or down proportionately for the bacode to remain readable.
As higher DPI printers are obviously more expensive, you will need to take into consideration 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, then a 200 DPI printer may be sufficient. Consider as well if you want to include an image such as your logo, or additional text such as a product description or size, or contact details for your company. High resolution printers have the additional benefit of being able to produce 2D barcodes such as QR codes or data matrix barcodes; and because you are also able to print using coloured thermal ribbon, you can potentially create an entire monochrome product label – complete with graphics and text – with your barcode printer if you wish. (and are willing to pay a larger investment sum, of course!)
Choosing the right substrate to print your barcodes on is also a big consideration. Barcode labels can come in a variety of materials ranging from normal paper to polypropylene and even polyester, depending on the environment in which the barcodes need to be scanned. Each different material will require the corresponding thermal ribbon type to be used in conjunction. Barcode labels can be printed onto plain straight-edged labels or to rounded or ‘butt cut’ labels which may be less likely to peel up at the corners.
Paper or semi-gloss labels:
These are the most commonly used labels and are printed with a wax ribbon, although direct thermal options are available as well. They are the least expensive form of barcode label and are relatively easy to use and apply. The vast majority of retail products can be labelled with standard semi-gloss paper labels and these can be ordered through SA Barcodes – you can find some more information on our website here. Unless the labels need to be used in an environment which is very high in moisture, or where there is the risk of the labels tearing, then these labels should be fine for most purposes. Another advantage of these labels is the wide variety of sizes available. Most standard semi-gloss barcode labels are either 40mm wide x 30mm high or the slightly smaller 30mm wide x 20mm high – although there is a huge range of larger sizes available as well, and some companies can supply them in a wide range of colours.
Polypropylene or Syntex labels:
These plastic-based labels are ideal for situations where there is a strong possibility of your labels being exposed to water or general wear and tear. They are especially useful for asset tracking systems as they will easily last for the lifetime of your assets and are not vastly more expensive than normal semi-gloss labels. Other uses include in the refrigerated and frozen food industries as well as haircare and pharmaceutical products. Polypropylene labels need to be printed with a wax-resin combination thermal ribbon, but do come in direct thermal varieties as well. Interestingly they may appeal to the ‘greenies’ out there as they are also recyclable. They are also oil- and alcohol-resistant.
These labels are incredibly tough and are advised for harsh outdoor environments or applications where the labels may come into contact with chemicals or other potentially damaging or corrosive conditions. They are resistant to scratching and tearing, as well as able to tolerate UV and heat exposure. Due to their rugged and durable nature they are of course a much more expensive option than the paper or Syntex labels discussed above, and in the vast majority of cases can be printed via thermal transfer method only. These labels require a full resin ribbon.
Other label types and applications:
There are many other materials on which barcodes may appear including vinyl, aluminium, polyolefin, Teflon and even stainless steel. ‘Piggy back’ labels with two peelable layers can also be created in cases where a label needs to be affixed to an object, and then removed and attached to another object. Aluminium tags in particular are an excellent choice for tracking assets which have a very high value, as they are virtually impossible to remove – especially when using the option where the adhesive is activated through the application of acetone. When used correctly the barcode cannot be removed from the asset without destroying the label or damaging the underlying surface. The tags include an anodised aluminium surface, are extremely strong, and remain legible and attached to the asset for its useful lifetime. Slightly cheaper peel and stick adhesive options are available as well when such a permanent solution is not necessary.
We hope that this covers most of the basic barcode labelling questions which you may have – if you have a very specific requirement do feel free to get in touch with SA Barcodes and we can always help you to source the best option for your needs.