Patent ID: 6975341

Claim:
A thermal printer for use with a dye donor web having successive dye transfer areas and two opposite edge areas alongside each dye transfer area, and capable of preventing crease formation in a dye transfer area that can cause line artifacts to be printed on a dye receiver, said printer comprising: a thermal print head in pressure contact with the dye transfer area and two opposite edge areas alongside the dye transfer area, and adapted to heat the dye transfer area sufficiently to cause a dye transfer from the dye transfer area to a dye receiver, but not heating the two edge areas sufficiently to allow a dye transfer from the two edge areas to the dye receiver, so that the dye transfer area is vulnerable to being stretched relative to the two edge areas to possibly form creases in the dye transfer area; a sensor and control device for determining variations in at least one operating parameter at said print head that can cause stretching of the dye transfer area relative to the two edge areas, during pressure contact of said print head with the dye transfer area and the two edge areas; and a pressure applying device connected to said sensor and control device to adjust pressure contact of said print head with the dye transfer area and two edge areas in accordance with variations that are determined via said sensor and control device, to prevent the dye transfer area from being stretched relative to the two edge areas, whereby creases will not be formed in the dye transfer area.