Printing takes place by applying heat to a heat-sensitive ribbon containing wax- or resin-based ink. The coloured ink ribbon is heated over a certain area, and the melted ink is then fully transferred from the ribbon on to the substrate. Depending on the heating process the size of the transferred area of ink can be varied. Halftones are generated by rasterisation (screening). The transfer of a homogeneous layer of colour leads to dots or areas with sharp edges. Special ink ribbons, e.g. with metallic pigments, can also be used. Thermal transfer printing is a possible integration technique for biodata / photo / signature integration.
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