No ink cartridge/ribbon/toner, the head is "solid state", and they can be very, very fast as the head is a linear array the width of the printable area. Also,

No ink cartridge/ribbon/toner, the head is "solid state", and they can be very, very fast as the head is a linear array the width of the printable area. Also, the cynic in me says that thermal paper is exceptionally fragile and this benefits return policies. Thermal receipt paper falls apart readily when wet, bleaches quickly, and of course turns black if exposed to too much heat.