Direct thermal fax machines can feed out faxes that immediately curl up, making them frustrating to work with.

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Disadvantages of Thermal Fax Machines

Although the advent of thermal fax machines allowed for faster and easier business communication for decades, the machines have some weaknesses, especially compared to newer technologies. Because of the distinctly chemical smell and feel of thermal paper, many people dislike using it. And because it's originally fed from a roll, thermal paper faxes have a tendency to curl up. The fact that it's difficult to write on can make it particularly frustrating as well.

But perhaps the biggest problem associated with thermal paper comes from the very quality that allows it to work. Because it's made to darken with heat, the documents might darken after printing if the paper is stored in a warm place. Leaving your important fax in a hot car, for instance, can easily ruin it. And, because laminating is a heat-related process, laminating thermal paper doesn't work very well [source: Leech Printing].

Even if you protect the thermal paper from extreme temperatures, it doesn't have a very long shelf life. Gradual fading can render it useless after too long, despite the fact that it often comes with a protective coating. Different sources say that we can only expect documents on thermal paper to be useful for about three to five years. Even in optimal conditions, which are at temperatures lower than 77 degrees Fahrenheit (25 degrees Celsius), thermal paper probably won't last much longer than that [source: Sandt Products].

Many organizations in charge of record-keeping make sure to avoid keeping documents printed on thermal paper. Instead, they recommend converting any important records to plain paper by using a photocopier. Office workers often do this by habit when they receive faxes on thermal paper. However, by using up both thermal and plain paper this way, the cost benefits of the thermal fax machine can go to waste and even make it more expensive than other fax machines [source: Passaic County].

Though it used to dominate the faxing world, thermal paper retreated to the back burner in the year 2000, when the use of plain paper officially over took "fax paper" itself in fax machines [source: Kenmochi]. Since then, it has continued to fall in popularity for fax purposes.

Even though thermal transfer fax machines don't use thermal paper, they have some disadvantages as well. For instance, especially when the thermal ribbon consists of mostly wax, the print tends to easily smudge. And unlike with the direct method where the only refillable need is the paper, replenishing the thermal ribbon periodically is necessary for the transfer method machines.

Both direct and transfer methods tend to only print documents of average quality at best, especially compared to ink-jet fax printers. Both kinds of thermal fax machines have environmental disadvantages as well. Thermal paper is not recyclable like plain paper is, and the ribbon used in the transfer method cannot be recycled either.

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