To apply images onto a blank plastic ID card, most ID badge printers use either dye sublimation or thermal transfer printing. Both processes use a thermal printhead to heat an ID card printer ribbon. Print heads used during the thermal transfer process heat (and melt) ink, while print heads used during dye-sublimation printing heat and vaporize dye.
Frequently an ID card printer and the ribbon it uses combine both technologies. This is most commonly used to produce a dense black color. While combining the colors cyan, magenta, and yellow – the dyes used in dye sublimation printing - do produce the color black, it is a sad, grayish black. More importantly, this black contains no carbon because it is made from dye, rather than ink and is therefore invisible to some bar code scanners.
Whatever single color of ink a thermal transfer ribbon has this color can be made to vary in intensity. For instance, a black resin ribbon can produce the color gray. But it does so by reducing the number of dots of black that are printed, rather than by actually transferring gray ink. Such pixilated effects produce an image that appears rough and coarse-grained.
Monochrome resin ID printer ribbons are easier on the budget than the ID printer ribbons that produce multiple colors. ID badge printers that use thermal transfer printing are ideal for organizations looking to print monochrome images, text and barcodes.