Preventing crease formation in donor web in dye transfer printer that can cause line artifact on print

Abstract

A thermal printer capable of preventing crease formation in a dye transfer area of a dye donor web that can cause a line artifact to be printed on a dye receiver during a dye transfer from the dye transfer area to the dye receiver, includes a print head having a bead of selectively heated resistive elements that make contact across the dye transfer area of the dye donor web and opposite edge areas of the dye donor web that are alongside the dye transfer area as the dye transfer area and the edge areas are progressively advanced under a longitudinal tension over the bead of resistive elements. Also, a control is adapted to selectively heat those resistive elements that make contact with the dye transfer area to effect a dye transfer from the dye transfer area to a dye receiver, and adapted to variably heat those resistive elements that make contact with the edge areas alongside the dye transfer area to effect a gradual drop in heat substantially from respective boundaries between the dye transfer area and the edge areas to an outer edge of each edge area that is spaced from the dye transfer area. As a result, when the heated transfer area and edge areas are subjected to a longitudinal tension, a relative resistance to being stretched will steadily increase towards each outer edge to maintain strength at each outer edge, but to avoid a sharp transition at the boundaries in order to prevent crease formation that can cause a line artifact.