Historically speaking, thermal printers have been monochromatic. In fact, this is the feature that allows them to be so cost-effective. However, more recent models are offering the possibility of printing two or even three colors. This feature is in high demand in stores that print labels, as they can save on long-standing preprinted labels.
Black remains the most common color because thermal printers were initially (and still are) very popular for creating barcodes. After black, red and blue are the most popular colors for these types of devices. This difference in color is obtained by heating the head pins to distinct temperatures. » learn more