Direct thermal printing uses chemically treated, heat-sensitive media  that blackens when it passes under the thermal printhead. Direct thermal  printers have no ink, toner, or ribbon. 


Their simple design  makes thermal printers durable and easy to use. Because there is no  ribbon, direct thermal printers cost less to operate than inkjet, laser,  impact, and thermal transfer printers. Most mobile printers use direct  thermal technology. 

Thermal media images may fade over time. If  the label is overexposed to heat, light, or other catalysts, the  material will darken and make the text or bar code unreadable. For these  reasons, direct thermal printing is not used for lifetime  identification applications. The readability of direct thermal labels,  wristbands, and receipt papers varies greatly, depending on the usage  conditions, but the technology provides ample lifespan for many common  bar code printing applications including shipping labels, patient and  visitor identification, receipts, and ticket printing. 

For  example, direct thermal labels can easily remain scannable after  spending six months in storage in a distribution center, and direct  thermal patient wristbands have a special coating that makes them water-  and chemical-resistant. Common thermal printing applications include:  shipping labels, including compliance labels; receipts; pick tickets;  coupons; event tickets; citations and parking tickets; name tags;  visitor passes; and more. 

In thermal transfer printing, a  thermal printhead applies heat to a ribbon, which melts ink onto the  material to form the image. The ink is absorbed so that the image  becomes part of the media. This technique provides image quality and  durability that is unmatched by other on-demand printing technologies. 

Thermal transfer printers can accept a wider variety of media than direct thermal  models, including paper, polyester, and polypropylene materials. Thermal  transfer printers can create extremely durable wristbands, asset tags,  and certification labels, in addition to common labels, tags, and  tickets. The specific label material and ribbon must be carefully  matched to ensure print performance and durability. 

By selecting  the right media-ribbon combination, as well as specialty adhesives,  users can create archival-quality labels to withstand temperature  extremes, ultraviolet exposure, chemicals, sterilization, and more.  Typical thermal transfer applications include: product identification;  circuit board tracking; permanent identification; sample and file  tracking; asset tagging; inventory identification; certification labels  such as UL/CSA; laboratory specimens; cold storage and freezers; and  outdoor applications.