What is dye sublimation?*

Dye sublimation is often used in color printing on a variety of substrates, including paper. A small heater is used to vaporize the solid dye material, which then solidifies upon the paper. As this type of printer allows extremely fine control of the primary color ratios it is possible to obtain a good quality picture even with relatively low printer resolution, as compared to other printer types of similar resolution. Standard black and white laser printers are capable of printing on plain paper using a special "transfer toner" containing sublimation dyes which can then be permanently heat transferred to T-shirts, hats, mugs, metals, puzzles and other surfaces.

The main difference between this and other types of printing has to do with heat. The vaporized colors permeate the surface, creating a gentle gradation at the edges of each pixel, instead of the conspicuous border between dye and paper produced by inkjets. And because the color infuses the surface, it is also less vulnerable to fading and distortion over time.

*Taken from Wikipedia