The three types of thermal technologies are thermal transfer, thermal dye sublimation, and thermal wax transfer.

Thermal Transfer

With thermal transfer technology, an image is transferred to the substrate from a plastic ribbon that is impregnated with colored pigments. A thermal head heats the ribbon, transferring the pigment to the printing surface. The process produces very high quality results, but it is slower and more costly than other technologies, such as ink-jet. Some types of products printed with the thermal transfer process include barcoded applications, labels, and colorful logos.

Thermal Dye Sublimation

Thermal dye sublimation is similar to the thermal transfer method except that dye pigments are used rather than thermoplastic ink. The dyes are contained in a transfer ribbon made of plastic film. The printing head contains thousands of heating elements, which are each capable of producing as many as 256 different temperatures. The varying temperatures of the heating elements cause varying amounts of pigment to be deposited from the transfer ribbon onto the printing surface. The result is different densities of color that are created in the image. When the dye pigments are heated, they go through a process called "sublimation", in which a solid changes directly into a gas. When the dye, in the form of a gas, makes contact with a specially coated paper, it changes back into a solid. The individual spots of dye created with the thermal dye sublimation process blend together to make an almost continuous tone image similar to that of an actual photograph.

Thermal Wax Transfer

Like the dye sublimation process, many heating elements are contained within the printing head, which control the amount of pigment that reaches the substrate. Instead of using a dye, a wax-based ink is used. The heating elements melt the wax-based ink and it is deposited onto the printing surface. With many wax thermal transfer printers, it is necessary to send the substrate through the equipment multiple times in order to print an image in full color. One pass is necessary for each of the process colors of cyan, magenta, yellow, and black. Even with this drawback, thermal wax transfer systems produce a very intense color image and the printed piece is resistant to moisture and ultraviolet light. Systems using thermal wax transfer technology are typically used for color proofing, presentation applications, and T-shirt printing.