How it works: Thermal transfer creates an image by melting the solid ink applied to the ribbon and transferring it to the receiving material. The receiving material may be uncoated paper, coated paper, or film. Although almost all pressure sensitive label paper can be printed by thermal transfer, the best results can be achieved by using carefully selected materials. Depending on the type of printing and the quality level required by the customer, a suitable ribbon and correct printing equipment with the correct settings must be used in combination.
Printers and thermal printheads: Standard thermal transfer printers use flat thermal printheads. When using a flat printhead, the time required to transfer the ink is long enough, so the receiving surface material does not require a special coating to improve its absorbency or smoothness. High-speed printers with a resolution of 300-600 dpi use near-edge/corner-edge printheads. At print speeds higher than 10 in/s, the ribbon will be removed when the ribbon is still molten, so the ink will transfer very quickly. For this type of thermal head, a special ribbon and a special coating on facial paper are required. The coating should have specific absorption properties to achieve rapid ink transfer, but allow the paper to maintain good pre-press performance, including flexographic printing.
Compatibility of label side and ribbon: The chemical and physical characteristics of the surface of the label blank material determine the type of thermal transfer ribbon that will be compatible. There are three main types of ribbons.
WAX ribbon: It is the most commonly used ribbon type, providing an economical solution for thermal transfer. The wax tape is designed for flat printheads and can be used with uncoated glossy paper with high water absorption.
Wax/resin ribbons: provide high performance for various end uses. The mechanical resistance of the printed image is very good. Wax/resin ribbons are suitable for non-absorbent materials such as coated paper and films.
Wax/Resin ribbons can be printed using near-edge/corner-side printheads. Resin Ribbon: Designed for very demanding applications. Images printed with resin ribbons are highly resistant to mechanical abrasion, solvents, and heat. This type of ribbon is commonly used for film surface materials such as PE, PP, and PET.