Summary of How Thermal Fax Machines Work
This article explains thermal transfer fax machines, which use heat to melt ink from a ribbon onto plain paper. Unlike direct thermal methods requiring special paper, this technique employs a ribbon with wax, resin, or composite ink layers. The process involves a printhead heating specific areas of the ribbon to transfer the image. While wax is cheaper but prone to smudging, resin offers high durability at a higher cost, and composites provide a balanced option.
Parts used in the Thermal Transfer Fax Machine:
- Heating element printhead
- Thermal transfer ribbon
- Polyester base film
- Ink layer (Wax, Resin, or Wax/Resin Composite)
- Protective coating
- Plain paper
Meltdown: Thermal Transfer Fax Machine
Though thermal paper is still useful for thermal printers of receipts and bar codes, a different kind of thermal method has taken over for most modern thermal fax machines [source: Sems]. Whereas thermal paper allows for direct application of heat to the paper, the thermal transfer method uses a third agent between the heating element printhead and the paper. This middleman is a ribbon that contains the necessary “ink.” However, it’s still considered a thermal fax machine because heat is necessary to transfer the ribbon’s ink onto the paper.
Unlike with the direct method, you don’t have to buy special paper for thermal transfer machines; instead this kind of machine can use plain paper. However, the printhead uses roughly the same basic technology as the one that prints on thermal paper. The printhead provides heat to the thermal transfer ribbon in the appropriate places and melts these areas down. This melting process makes the ribbon release the ink it contains onto the paper fed through the machine.
The ribbon itself can consist of a base film made of a material such as polyester, and attached to that is the substance that makes up the ink[source: Watanabe]. Another layer of protective coating keeps it from sticking to the printhead. The ink layer is typically made of one of three materials:
- Wax: Thermal ribbons consisting of wax are often the cheaper option. However, these ribbons don’t produce the highest quality print-outs. Documents printed using wax thermal ribbons can easily smudge after being exposed to heat or scratched.
- Resin: Resin is a material secreted naturally from certain plants or artificially manufactured. Though it originates in a viscous (gooey and sticky) state, it later hardens. Resins are extremely useful in the manufacturing of such things as paints and plastic. Using a resin material, thermal ribbons print a higher quality document that doesn’t easily smudge. However, it’s more expensive than the wax kind.
- Wax/Resin Composite: This is a popular middle-of-the-road choice material for thermal ribbons because it’s not as expensive as resin and not as low quality as wax.
So, in the thermal transfer method, the printhead receives the encoded information about when and where to heat up, just as in the direct thermal method. However, this time, the ribbon runs along between the paper and the printhead. As the printhead heats the ribbon’s ink material, it releases the ink, which proceeds to melt onto the paper.
Knowing the thermal methods of these kinds of fax machines allows us to understand their advantages, which we’ll discuss on the next page.
For more detail: How Thermal Fax Machines Work
- How does thermal transfer differ from direct thermal printing?
Thermal transfer uses a third agent, a ribbon containing ink, between the heating element and the paper, whereas direct thermal applies heat directly to special paper. - Can thermal transfer fax machines use plain paper?
Yes, unlike direct thermal machines that require special paper, thermal transfer machines can use plain paper. - What materials are typically used for the ink layer in thermal ribbons?
The ink layer is typically made of one of three materials: wax, resin, or a wax/resin composite. - Which type of thermal ribbon produces the highest quality print-outs?
Resin ribbons produce a higher quality document that does not easily smudge compared to wax ribbons. - What are the disadvantages of using wax thermal ribbons?
Documents printed with wax ribbons can easily smudge after being exposed to heat or scratched. - Why might someone choose a wax/resin composite ribbon?
It is a popular middle-of-the-road choice because it is not as expensive as resin and not as low quality as wax. - What role does the protective coating play in the ribbon?
The protective coating keeps the ink from sticking to the printhead. - How is the ink transferred onto the paper in this method?
The printhead heats the ribbon's ink material, causing it to release and melt onto the paper fed through the machine.
