Over the years there have been a variety of methods for a computer to commit its thoughts to paper. Be it a daisy wheel, a dot matrix, a laser, or an inkjet, we’ve all cursed at a recalcitrant printer. There’s another type of printer that maybe we don’t think of quite as often but is workhorse in a million cash registers and parking ticket machines: the thermal printer. These mechanisms can be readily found as surplus items and have made their way into more than one project here over the years. [HomoFaciens] has taken thermal printing a step further by building a plasma printer from scratch that makes use of the thermal paper.
A thermal printer does its job as its name suggests, by burning the image into the paper. It may not deliver the best quality print, but scores on not needing ink ribbons, cartridges, or toner. This DIY version uses an off-the-shelf battery-powered plasma lighter to do the job, mounted on a 3D printed XY printer mechanism driven by two stepper motors. Behind the scenes is an Arduino Uno, which receives its instructions via USB from a command-line program on a Linux box. It’s admitted that this is hardly the pinnacle of printing technology, but it does at least make for a fascinating project. You can see it in action in the video below the break.
This isn’t [HomoFaciens]’ first printer, we’re instantly reminded of this ink drop printer from a few years ago.
Thanks [Baldpower] for the tip.
I’m really sure that the heating elements in every thermal printer you can buy never reaches the flashpoint of thermal paper. In contrast, I’m just as sure that a plasma lighter mechanism always exceeds that flashpoint. There is obviously a safety issue.
Meh, just make sure it passes the standard fault code…
https://en.wikipedia.org/wiki/Lp0_on_fire
…if someone really wants to bring my printer to the mass market, ship it with a fire extinguisher ;-)
The last command sent to the printer is
Halt and catch fire
Can probably get better precision by placing the electrodes closer together, and better DPI by making multiple low-power passes with slight offsets (i.e. if you can move the print head in .1mm steps, do the first pass with .2mm steps at offset 0.0mm and a second with .2mm steps at offset 0.1mm). It would also give time for the paper to cool down locally to avoid burning for large areas.
Source: tried to write my own Raster Image Processor and Epson print driver to get more control over the ink channels (to open up the possibility of using different colors than it’s standard CYMK + Lm,Lc) and it turns out the model I have can only print at about 720DPI horizontal, but can actually position the print head at about 5760DPI.
If you try to set a new dot too close to an existing one, the plasma arc will rather go through the existing, close-by hole rather than forming a new one. A second issue is that the paper gets destroyed (perforated), so a high pixel density means vaporizing the structure.
That was the standard way to get decent resolution on ye olde dot matrix printers. Some drivers did 3 or 4 offset passes. Beat the paper back into pulp though:
Yep. the Oki320’s “NLQ” mode ran two passes over the same line, with a single step from the feed motor to offset the paper. Slow as heck, but with a ribbon and printer in good condition, it looked pretty good.
(on a printer that’s been beat to hell n back, it looked… _less_ than good. But those were usually candidates for a rebuild anyway…)
Galinha pintadinha?
Really?
Thanx, now I won’t be able to get that song out of my head for the rest of the day.
“ A thermal printer does its job as its name suggests, by burning the image into the paper”
This is not meant literally right? Conventional thermal printer does not burn the paper.
Oxidation is burning, pretty sure thermal paper is rapidly oxidized when heated.
It is chemically treated paper with a compound that has a permanent color change when heated. Early on the print was blue and faded over time and the paper was as thick as “adding machine paper” or 20# paper. The ones used today in cash registers are similar but a LOT faster. I suspect if you put a register receipt near your soldering iron you will see.
striking over it with a fingernail already produces enough friction “heat” to make it turn black
Wikipedia says that most thermal paper consists of a transparent pigment and a developer, and getting it hot allows the two to mix and become dark. So… apparently not?
I remember from watching The Wonderful Life of Machines’ episode on the fax machine, early telefaxes used a similar method to print but used an electrode on a synchronised pendulum
does this even need thermal paper in the first place?
No. I did not use thermal paper in the video. It is normal paper.
Wikipedia says that most thermal paper consists of a transparent pigment and a developer, and getting it hot allows the two to mix and become dark. So… apparently not?
No one has mentioned the venerable ZX Printer (see https://en.wikipedia.org/wiki/ZX_Printer), which used a spark to remove a metallised top layer revealing a black paper underneath. The result is black on silver text.
It has been mentioned on YouTube comments. I did not know about that printer before and it is a really interesting piece of hardware.
Even if it’s probably just a thermal printer with sparks, this really isn’t complete without mentioning: Secret Life Of Machines – The Fax Machine: https://youtu.be/IaCfs5Xb-EI (RIP Rex.)
Thanks Jaap, that was very enlightening! I never made the connection between a lathe and a fax!
The uptalk at the end of each phrase is super annoying.
Since this can print on plastic sheets it would be perfect for making printing sheets for a Gestetner, and if you don’t know what that is check out the link below.
https://en.wikipedia.org/wiki/Gestetner
This type of duplication was used in my early school days (man I am old…). I still remember the smell of that special ink used in those machines.
Does borax treated paper still burn, or just char nicely? ;-)
Think it raises the ignition point way high. On the plus side, if you make enough rolls of boron impregnated paper to stack 3 cases deep all round your house, you’ll be protected from fast neutrons.
“A thermal printer does its job as its name suggests, by burning the image into the paper. It may not deliver the best quality print, but scores on not needing ink ribbons, cartridges, or toner. ”
Yes, but an ordinary off the shelf thermal printer requires special thermal paper impregnated with chemicals that make it turn coors when heated (not to the point of burning). It’s a little like saying You don’t need ink because you are only going to use special paper that comes with the ink already in it.