Direct thermal printing uses virtually the same process as thermal transfer printing - with one exception. Direct thermal printers do not use ribbon. In direct thermal printing, the thermal process occurs on the paper substrate itself - requiring a specially coated paper for optimal performance. The heat generated from the print head causes a chemical reaction with the top layer of the coated paper that essentially burns the transmitted image onto the paper.
Advantages
Images produced by direct thermal printing are clear and defined; and direct thermal printers are cheap, simple to operate and easy to maintain. Direct thermal printing for bar code labeling is certainly an improvement over ink jet and laser technology, especially when it comes to speed and resolution.
Disadvantages
Direct thermal images are far less durable than thermal transfer printed images; and direct thermal technology is also constrained by substrate restrictions. The coated paper required by direct thermal printing is very sensitive to light, heat, and abrasion - limiting the range of applications for direct thermal printing to short-term projects. Direct thermal images have no chemical resistance, and very short life spans. Primary uses for direct thermal printing are "Point-A-to-Point-B" applications, such as baggage checking in airports, or parcel delivery. Bar coding projects requiring durable images and substrate flexibility are not well served by direct thermal printing technology. |
