| abstract |
A base film for a thermal transfer ribbon which is a biaxially oriented polyester film comprising polyethylene-2,6-naphthalene dicarboxylate as a main constitutional element, wherein in a temperature-dimensional change curve under load in a longitudinal direction of the film, the dimensional change from the original length of the film at temperatures of up to 200° C. is 1.0% or less and the dimensional change from the original length of the film at temperatures of up to 230° C. is 3.0% or less. This film may have a coating layer of at least one water-soluble or water-dispersible resin selected from the group consisting of an urethane resin, polyester resin, acrylic resin and vinyl resin-modified polyester resin, on one side thereof. The base film gives a thermal transfer ribbon which has excellent adhesion to a sublimation-type ink layer and excellent printing performance without blurred ink at the time of high-speed printing and without wrinkles formed by friction with a head. |