They have a short useful lifespan, but in many cases that is all you need, and in addition, if you keep the labels out of UV radiation, they will have an extended lifespan. Direct Thermal printing should be considered when you have applications that only need temporary labels. Thermal Transfer Printing , on the contrary does require a roll of heat-sensitive ink ribbon. Because it utilizes a ribbon it does not require heat-sensitive paper media.
Heat transfers the appropriate image from the ribbon onto the paper label.
Please give us a call if you have any questions or need more clarification between the differences of these two printing methods. We can recommend the appropriate choice for your unique application.