Defining the Differences between Direct Thermal and Thermal Transfer Printing

Most companies choose thermal technology to print bar codes due to the high print quality, flexibility with media, low-maintenance, and durable nature of the printers. There are two different thermal printing methods, though: direct thermal and thermal-transfer. Each method utilizes a thermal printhead to apply heat to the surface being printed, but the technologies differ slightly.

With direct thermal, the printer creates an image directly on the label and no ribbons, ink or toner are used. Instead, chemically treated, heat-sensitive media darkens when it passes under a thermal printhead. Direct thermal printers are durable, simple and easy to use. They cost less to operate than inkjet, laser, impact and thermal transfer printers. The media for direct-thermal printers is more sensitive to heat, light and abrasion, though. With direct thermal media, images can fade over time and if they are exposed to a lot of heat or light, the material can darken, making an image unreadable. So, direct thermal printers are not typically used for sensitive lifetime applications, but are often used for shipping labels, pick tickets, coupons, receipts, and tickets.

Thermal transfer printing melts ink onto the material by applying heat to a ribbon. The ink soaks into the material and becomes part of the media. If the label material and ribbon are properly matched, the image quality and durability of thermal transfer printing outlasts direct thermal printers. The printers can also accept a wider variety of media and create extremely durable asset tags, wristbands, certification labels, tags and tickets. Other archival-quality labels can be created to withstand temperature extremes, ultraviolet light, sterilization chemicals and more. This can be especially useful with circuit board tracking, asset tagging, inventory control, laboratory specimens, cold storage and outdoor applications.

It’s important to think about all of your needs when determining which barcode printer is right for your application. While direct thermal printers may be sufficient for most circumstances, thermal transfer printers are needed for special applications. There’s quite a bit of information on choosing thermal label printers at http://www.ryzex.com/light-industrial-printing-knowledge-center.aspx.