Resistive-head thermal dye transfer printing is a digital printing method in which thermal energy is used to create photographic quality output by the transfer of dyes from a donor ribbon to a receiver that are in intimate contact. Dye donor elements consist of support, dye layers, adhesive layers, laminate overcoat layers, and slipping or heat-resistant layers. Slipping (or slip) layers are coated on the opposite side from the dyes on the thermal donor. The primary function of the slipping layer is to facilitate transport of the donor under the thermal printhead. These layers have several characteristics, including the ability to provide low and constant friction over the entire printing temperature range, to be noncontaminating and nonabrasive to the printhead, and noninteractive with the other layers when spooled. Slipping layers typically contain lubricants, polymeric binders, solvents, and other addenda to achieve photographic quality printing. Work over the past few years has focused on the redesign of the slipping layer for enhanced performance features. The result is a layer that provides enhanced lubrication, improved retransfer protection from the dye side to the slip side upon spooling, improved fold performance in the printing operation, and cleaner printheads during printing.
David G. Foster, "Slipping Layer for Thermal Donor" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP23), 2007, pp 155 - 158, https://doi.org/10.2352/ISSN.2169-4451.2007.23.1.art00039_1