A dye-sublimation printer is a computer printer which uses heat to transfer dye onto materials such as a plastic, card, paper, or fabric. The sublimation name was first applied because the dye was considered to make the transition between the solid and gas states without going through a liquid stage. This understanding of the process was later shown to be incorrect. There is some liquifying of the dye. Since then, the process is sometimes known as dye-diffusion, though this has not eliminated the original name. Many consumer and professional dye-sublimation printers are designed and used for producing photographic prints, ID cards, clothing, and more.
These are not to be confused with dye sublimation heat transfer imprinting printers, which use special inks to create transfers designed to be imprinted on textiles, and in which the dyes do indeed sublimate. These are done at lower temperatures but higher pressures, particularly in all-over print processes.
Some dye-sublimation printers use CMYO (cyan magenta yellow overcoating) colors, which differs from the more recognized CMYK colors in that the black is eliminated in favour of a clear overcoating. This overcoating (which has numerous names depending on the manufacturer) is also stored on the ribbon and is effectively a thin layer which protects the print from discoloration from UV light and the air, while also rendering the print water-resistant.
For ID card printing, text and bar codes are necessary, and they are printed by means of an additional black panel on the (YMCKO) ribbon. This extra panel works by thermal transfer printing instead of dye diffusion: a whole layer, instead of just some of the dye in the layer, transfers from the ribbon to the substrate at the pixels defined by the thermal head. This overall process is then sometimes called dye diffusion thermal transfer (D2T2).
The dye-sublimation printing process is used to print on polyester or other synthetic fabrics. It is used for applications such as T-shirts, banners, table covers, id cards, sportswear and flags. The original printers were an electrostatic technology using toners but now are generally large format inkjet printers using specially formulated inks. The dye sublimation inks are a disperse dye suspended in a liquid solvent, like water. The images are initially printed on coated heat-resistant transfer paper as a reverse image of the final design, which is then transferred onto polyester fabric in a heat press operating at a temperature around 180 to 210 C (375 F). Under high temperature and pressure, the dye turns into a gas and permeates the fabric and then solidifies into its fibers. The fabric is permanently dyed so it can be washed without damaging the quality of the image. Shelfies and Blue Notes are two such companies that use this method.
Advantages of dye-sublimation over other methods of textile printing: images are permanent and do not peel or fade, dye does not build up on the fabric.
Colors can be extraordinarily brilliant due to the bonding of the dye to the transparent fibers of the synthetic fabric, truly continuous tones can be achieved that are equivalent to photographs, without the use special techniques such as half-screen printing, and the image can be printed all over the entire item, with no difficulty in printing all the way to the edges.
Disadvantages are the printer speed is low and any creases in the apparel during printing leave blank spots.