What's a thermal transfer printer?
A thermal transfer printer is a type of printer that creates labels and signs by melting wax or resin-based “ink” onto paper, tape (made of nylon, polyester or vinyl), and even materials like heat shrink tubing. Thermal transfers printers are known for their smear-proof images and resistance to fading and are particularly well suited for creating barcodes.
How do thermal transfer printers work?
The main functional component of a thermal transfer printer is its printhead, which spans the width of whatever tape or printing medium the printer is built to handle. The thermal printhead is made up of tiny heating pins, each of which represents a single pixel (pixel size and density differ by the printer – many handheld models range between 203 and 300 dpi, or dots per inch).
The key material used in thermal transfer printing is wax or resin-based ink, which is loaded into the printer in the form of a ribbon: in a solid state, applied in a very thin layer to a backing of polyester film. This “ink” ribbon is drawn through the printer between the printing medium (paper or tape, as discussed earlier) and the printhead.
The printhead is controlled by a microprocessor, which determines which heating pins need to be activated in order to form a specific image. From there, signals are sent to the selected pins, causing them to rapidly heat and cool against the ink ribbon, melting and transferring ink off of its backing film and onto the blank label surface.
What is the difference between wax-based and resin-based thermal ink ribbons?
The final results might not differ much to the eye, but the truth is that all thermal transfer inks are not created equal. Always be well aware of the demands of your particular application before you choose which type of transfer ribbon to use.
Because of their distinctly different characteristics, wax and resin generally can't be interchanged, but in some cases, they're actually combined into a wax-resin hybrid ink. Below, read a little more about the traits of – and best uses for – the 3 main types of thermal transfer inks.
Wax: Wax thermal transfer ribbons are most commonly used for printing onto paper labels. The images they produce can last for years, but not without protection: wax-printed labels need to stay dry, and are highly sensitive to abrasives, chemicals, and oils, which can wear or melt wax inks away.
Wax-Resin: Wax-resin compounds work well with smooth - as well as coated -paper labels. The wax-resin combination produces a more refined image, and while it still needs to be guarded against excessive moisture, it offers much more durability than plain wax.
Pure Resin: Out of the three, the pure resin is the toughest stuff you can print a thermal transfer label from, but it isn't designed for use with paper. Resin-based thermal inks are engineered to fuse onto vinyl, polyester and polypropylene labels, and are incredibly durable. Plastic label/resin ribbon combinations are made to weather the harshest environments: they won't fade in sunlight, can be immersed in water, and – depending on the material – can be resistant to damage from oils and chemicals. Resin is the “ink” of choice for marine, automotive, aircraft, industrial, and hazardous chemical applications.