Label printers usually operate based on the direct thermal printing approach or thermal printing therefore label printers can be alternatively named as thermal printers. The definition of a thermal printer according to Webopedia is a printer that uses heat to transfer a particular impression onto the paper. There are two different types of thermal printers; thermal wax transfer and direct thermal. Majority of label printers usually falls under the category of direct thermal printing.
Direct thermal printing is where the label printer burns dots on the coated paper by the heating elements in the print head when the paper passes over it. Basically this means label printers are non-impact printers that use heat to register an impression on to the paper. This is a common mode of operation involved when the printer is used to print barcodes.
Thermal wax transfer on the other hand uses wax- based ink for printing. The print head melts the wax and transfers it to the ribbon which than transfers it to the paper. The wax will become permanent once it is dried. These printers are fast but the printing results may not seem to be quite realistic and that is why direct thermal printers are given more preference.
Label printers or direct thermal printers are easy to use, low in cost and compact but it has one disadvantage. Direct thermal labels produced by label printers do not have a very long period of lifespan. The labels start to fade and can last from 6 months up to a year only; this process can be hastened if there is exposure to sunlight, presence of humidity and heat.
The fact that the labels start to fade within a period of time is not considered to be a major disadvantage as most label printers produce labels that are used within a limited time span. The ability to provide high quality results in a short period of time at a low cost makes these thermal printers too attractive that the disadvantage seems to be overridden.