In this article, we're going to focus on inkless printers - it might sound like black magic, but it's actually quite simple once I explain a few basics. Let's jump in!

Inkless printers

You've probably handled something printed by an inkless printer today - they're used in cash machines, petrol pumps, till receipts and National Lottery booths, to name only a few. There are two kinds we're going to look at today - the standard thermal printer, and Xerox's futuristic UV printer, which is currently under development.

Of course, if there's no ink, something else has to bear the changes associated with print. Paper is the best candidate for this - and, in a thermal printer, the paper works the magic. Special, thermochromic - from thermos (heat) and chromia (colour) - paper is heated at different points. Where it's heated, it turns black (most thermochromic paper). Some thermal printers can vary the heat they apply at the printhead, and this is occasionally taken advantage of by dually thermochromic paper, which will turn another colour in addition to black.

Where is this stuff used? Well, we've given a few examples above, but they're also used in fields such as oceanography and engineering, where their simple design and low cost are important factors.

So what's going on with a UV printer? Again, it's all in the paper - Xerox has been working to manufacture per coated with a UV-chromic covering: it changes colour depending on the amount of ultraviolet light shone on it. This also means that the paper is reusable - it can be 'wiped clean' by one frequency of UV light and rewritten on by another.

The catch? As of 2007, Xerox have only managed to create paper that holds the print for a few days. So, unless you're a fast reader, a UV printer isn't for you just yet.

Pros and Cons of Inkless printers

  • The obvious one. They don't need ink! You never, ever need to buy ink again.
  • They're simpler than other printers. That means they're cheap to buy, easy to maintain and cheap to run. It also means they can afford to be much smaller than regular printers (in fact, Nintendo produced a Gameboy printer not so long back designed to be plugged in to the cartridge port on a Gameboy).
  • They don't do colour. Well, not more than two. So if you're thinking of a thermal printer for printing photos, you might need to think again.
  • You have to buy thermochromic paper. While you might save on ink, you'll spend on paper. And, to make things harder, thermochromic paper is easy enough to come by in till receipt sizes, but harder to find in A3. So, if you're thinking this is a cheap way to print out your latest novel, you might want to consider a laser printer instead.

And that's it! That brings us to the end of this comparison series. Hopefully it's helped you to pick a printer, troubleshoot yours or just think about printers more deeply. All the best, and let us know what you think, below!

Happy printing!