Thermal Transfer Printers:

This is a raster hard copy device. Pigments from coloured wax paper are transferred to plain paper by finely spaced heating nibs. Both of the papers are drawn together over the strip of heating nibs that are selectively heated to cause the pigment transfer. Nibs may be heated and cooled quickly and single colour hard copy image may be created in less than one minute.

Thermal Sublimation Dye Transfer Printers

These are similar to thermal transfer printers in acting except the heating and dye transfer process allow 256 intensity each of cyan, magenta and yellow. The procedure is slower than wax transfer, but the quality is near photographic.