In sublimation printing, colours are not laid down as individual dots, as is done in inkjet printers. If you looked inside a dye-sublimation printer, you would see a long roll of transparent film that resembles sheets of red, blue, yellow, and grey colour cellophane stuck together end to end. Embedded in this film are solid dyes corresponding to the four basic colours used in printing: cyan, magenta, yellow and black. The print head heats up as it passes over the film, causing the dyes to vaporize and permeate the glossy surface of the paper before they return to solid form.
So the main difference between this and other types of printing has to do with heat. The vaporized colours permeate the surface of the paper, 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 colour infuses the paper, it is also less vulnerable to fading and distortion over time.