Background
Thermal media can be direct thermal paper/film, dye diffusion ribbon or thermal mass transfer ribbon. For thermal mass transfer printing to occur, the ribbon and a receptor paper must be pressed against the printhead. When a heater is fired, a wax/resin binder containing pigment melts and re-solidifies on the surface of the receptor paper. It is bimodal, meaning that a dot is either 100% printed or 0% printed, with no gray levels in between. The advantages of thermal mass transfer printing are highest optical density, highest speed and most flexibility with respect to receptor media.
![[CORNER EDGE RIBBON PEEL]](../images/IMG_tph_tech_QRP-KCE.gif)
Ribbon Peel-Off Issues
The geometry of conventional flat printheads requires that the ribbon remain in contact with the receptor for some distance after the melt. By the time the ribbon can be pulled away from the receptor, the wax/resin will be somewhat solidified. To make sure that it transfers 100%, it is required that it be completely solidified. This essentially requires a cooling time, which limits the speed of the printer. Solid peel off also limits the choice of receptors to those to which the wax/resin will bond more strongly than it bonds to the ribbon substrate.
With the Kyocera corner edge printhead, the ribbon substrate is immediately separated from the liquid wax/resin. The extremely fast performance of Kyocera corner edge printheads certainly comes from their high print energy, small glaze volume, history control and straight paper path. But it also comes from very quick ribbons, which are enabled by the quick peel off geometry. Once a liquid peel off can be assumed, a new class of resins can be used that will adhere to receptors which could not previously be thermally printed.
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