A hospital lab technician recently asked, “I want to upgrade from handwritten labels. Which is better for lab labeling: a direct thermal or thermal transfer printer?”

Here’s the simple answer: Use a direct thermal printer for temporary and general-purpose labels and a thermal transfer printer for sample and specimen labels that come in contact with chemicals, extreme temperatures, changing lab conditions, and long-term storage.

Here’s why. Direct thermal and thermal transfer print technologies function differently. Direct thermal labels are chemically treated to blacken when the print head applies heat to the label surface. This means you don’t need ink, toner, or ribbon for printing, but there is a trade off – you’ll need to replace your print head more often.

Unlike direct thermal, thermal transfer labels require a printer ribbon. As the label stock passes through the printer, the print head instantly melts the ribbon onto the label for a long-lasting impression. Ribbon material comes in resin (highest quality), wax-resin (medium quality) and wax (most economical). It is very important that the right ribbon material is selected to work with your printer and label stock so that the label material will perform to meet the needs of your application. For cryovial and microscope slide labels, it is best to use a polyester label stock with a permanent acrylic adhesive and matched with a resin printer ribbon that has been lab-tested to endure harsh chemicals, extreme temperatures, and changing lab conditions.

Direct thermal print technology is an affordable choice for short-term lab identification applications such as patient ID wristbands and general-purpose labeling. Direct thermal technology is not suitable for long-lasting identification, because over time, light and heat will cause legends and barcodes to fade away while the label material darkens. This makes text hard to read and barcodes virtually unscanable.

For your lab specimen identification, choose reliable, long-lasting, thermal transfer print technology. Dasco supplies Brady thermal transfer labels which are designed and lab-tested to endure harsh chemicals, liquid nitrogen, autoclave, hot water baths, and long-term storage without smearing or fading or falling off.

Whether you choose a direct thermal or thermal transfer printer will ultimately depend upon the nature of your lab application, the length of your label life, and the conditions of your label environment.

If your application requires your labels to endure extreme temperatures, harsh chemicals, changing lab conditions, and long-term storage, then a thermal transfer label printer would be your best choice. If you have a short-term label application, then a direct thermal label printer would be an affordable solution. If you think you’ll need both, some label printers are equipped with thermal transfer and direct thermal print technologies in the same unit.

For assistance in choosing a label printer or selecting the right label stock and ribbon for your application, call Dasco toll-free at 1-877-855-2235 or visit www.DascoLabel.com.