Patent ID: 6977669

Claim:
A thermal printer capable of preventing crease formation in successive dye transfer areas of a dye donor web that can cause line artifacts to be printed on a dye receiver during dye transfer from each dye transfer area to the dye receiver, said printer comprising: a thermal print head for heating a dye transfer area of the dye donor web sufficiently to cause dye transfer from the dye transfer area to the dye receiver, but not heating two opposite edge areas of the dye donor web alongside the dye transfer area sufficiently to allow dye transfer from the two edge areas to the dye receiver, so that the dye transfer area is vulnerable to being longitudinally stretched relative to the two edge areas to possibly form creases in the dye transfer area; a crease-preventing platen roller movable to adjacent said print head for supporting both the dye receiver and the dye transfer area and two edge areas partially wrapped longitudinally about said platen roller, so that respective wrap angles are formed for the dye receiver and for the dye transfer area and two edge areas relative to said platen roller, and being configured to urge the dye transfer area and two edge areas to spread in opposition to crease formation during dye transfer from the dye transfer area to the dye receiver; and a wrap angle regulator movable for increasing at least the wrap angle of the dye transfer area and two edge areas relative to said crease-preventing platen roller, whereby said platen roller can urge more of the dye transfer area and two edge areas to spread.