Thermal Transfer Printing – 3
Print heads are available in several resolutions. For example; options are 203 dpi, 300 dpi, and 600 dpi. Each dot is digitally addressed. That is why it is called a digital printing method. When a dot is addressed, it immediately heats up to a pre-set (adjustable) temperature.
The heated element immediately melts the wax or resin-based ink on the side of the ribbon film facing the substrate, and this process, in combination with the constant pressure being applied by the print-head locking mechanism immediately transfers it onto the substrate.
When a dot "turns off", that element of the print head immediately cools down. The melting stops in that part of the ribbon. When the substrate (paper, cardboard, fabric, vinyl, …) comes out of the printer, it is dry and can be used immediately.
Carbon ribbons are on rolls and are fitted onto a spindle or reel holder within the printer. The used ribbon is rewound by a take-up spindle, forming a roll of "used" ribbon. It is termed a "one-trip" ribbon because once it has been rewound, the used roll is discarded and replaced with a new one.
If one were to hold a strip of used carbon ribbon up to the light, one would see an exact negative of the images that have been printed. The main benefit of using a one-trip thermal transfer ribbon is that providing the correct settings are applied prior to printing, a 100% density of the printed image is guaranteed, in contrast to a pre-inked ribbon on a dot-matrix impact printer ribbon, which gradually fades with usage.
For more: https://en.wikipedia.org/wiki/Thermal-transfer_printing