A variety of roles
Setting aside the physical requirements, logistics labels also undertake a variety of important roles. They identify single items at the retail point of sale, in catchweight applications, particularly for foods. Here, the label’s dual readability role – correctly identifying the contents for the consumer and enabling the sales assistant to successfully scan the item at the checkout – is critical. In warehousing and other inventory situations – at single item or pallet level – labels are key players in stock control, both at single item and pallet level. They can also perform a major function in product authentication and tamper-evidence – often at the leading edge of today’s security labelling technology. Using a self-adhesive label as a carrier of security solutions can be a cost-effective solution for brand owners, and converters active in the self-adhesive label production market are contributing extensively in this market.
Self-adhesive labels, whether pre-printed or not, can employ all the types of variable information print (VIP) required to perform these different functions. They will often combine alphanumeric (product name or code) identifiers, for reading with the human eye, with digital identifiers such as barcodes, for use with special readers employed in the track-and trace technologies. Automated stock control makes tough demands on labels; and as well as dependable adhesive technology, the labels must feature a face material – usually paper but, today, also film – that delivers high-quality print by a variety of VIP technologies.
The barcode
Barcodes as product identifiers are today’s most ubiquitous track-and-trace technology. They have been around for nearly half a century, but they still play a key role in supply chain management in many different ways, securing and documenting a variety of information from unique product identifier to production location, batch number, and expiry date. The simple one-dimensional barcode has been joined today by two-dimensional barcodes and, based on the 2D technology, even three-dimensional barcodes. Self-adhesive labels can accommodate even the most advanced barcode technologies – even those associated with today’s product authentication technologies.
Variable information print technologies
In all its transport and logistics applications, a barcode is often applied to a product via a simple label, sometimes pre-printed with a logo or other message, often in partnership with other variable information print. The image today can be created by the direct thermal, thermal transfer, inkjet (including flatbed), and laser print processes. Barcodes may also be applied as unique identifiers on primary product labels via digital print units in modular narrow-web press configurations, or via the standalone reel-to-reel digital label presses.
The mature direct thermal technology, which creates images using heat on a heat-sensitive substrate, primarily serves the retail market, particularly for catchweight food labelling. It offers ease and reliability of use for short-life applications, and delivers relatively low-cost quality barcodes at reasonable print speeds. These characteristics also make direct thermal an obvious choice for transit product identification and tracking labels, eg for parcel distribution, as well as for outer case and pallet markings.
It is worth noting that traditionally self-adhesive Bisphenol-A (BPA) has been used in thermal papers as the standard image developer – but current concerns around its possible toxicity have led the manufacturers of self-adhesive thermal labelstocks to offer non-BPA alternatives.
Thermal transfer, using ink ribbons with a thermal printhead, is one of the most flexible variable information print technologies, due to the variety of ribbons and printable receiver label materials (many UL approved) available, and its ability to print in colour. Image quality and durability can be very high, so thermal transfer has been an ideal choice for industrial label applications such as chemical drum labels and durable component markings for electronic, automotive, or white goods.
