Sherwood's patent for laser marking
UK-based colour-change specialist Sherwood Technology has been awarded a US patent for its innovative method for laser marking edible products. Its coding, marking and printing additive allows a safe, high contrast image to be formed onto edible products in the pharmaceutical and confectionery industries such as pills, capsules, and hard-shelled sweets. The process utilises a unique chemistry that reacts with a beam of low power laser light, changing colour and thereby creating an image. It is a true 'on demand' digital imaging process that allows variable text and images to be printed sequentially in real time.
Previously the most common method of marking pills required a mechanical embossing or surface printing method, both of which result in a significant number of rejects due to damaged or cracked product. Non-contact printing methods such as inkjet are largely unsuitable due to the spread of the ink droplets and slow drying of the ink.
Sherwood's additives, which come in the form of a dry powder or water-based solution, are applied to the surface of the tablet as part of an existing or additional coating process, and then marked by a low power CO2 marking laser. The coating undergoes a chemical colour-change, creating a high contrast, stable image that is 100% edible.
The company says benefits of using this process include no production line consumables or high energy consuming labellers; faster line speeds, lower costs, and less wastage (defective product); compatibility with most pharmaceutical tablets and capsules; and high fidelity image resolution and marking.
'The significance of this invention has been recognised through the awarding of this US patent,' said Andrew Jackson, applications marketing manager of Sherwood Technology. 'The high sensitivity of edible pharmaceutical goods has always been an issue for the marking process. This technique has met the challenge, and offers the perfect solution for the marking of products meant for consumption.'
The technology will be available through a series of application licensing agreements and strategic partnerships.