Building a plain paper printer

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This discussion on hackaday.io, itself a most interesting web resource for a universe of ideas, questions the lack of hardware choices for persons keen on enjoying the freedom to hack one’s own printer, either at work or home.

It may seem hard to believe, but early printers for computers actually came with code that users could load up on their (room sized) devices, and tweak to achieve some needed variation, or just for the heck of it.

One day, at MIT, a new printer was delivered, and it came with locked code. One of the researchers using the department computer was outraged, and tried to persuade the manufacturer to make the code available for modification.

This did not happen. Out of that small loss, a great victory emerged, the world of Free Software, and the Free Software movement. The researcher, Richard Stallman, has become the lead figure in a pantheon of great people who have been at the forefront of a demand that technology be at the service of people, and not the other way around, which is the foundation of the industrial society.

That husbanding of knowledge is also the underlying philosophy of fiercely competing political systems, despite claims to the contrary.

To return to the first linked page, do read the exchanges between James Newton, Starhawk and Peter Walsh, in particular, though the whole thread makes for good reading.

It seems that it is actually quite possible to purchase some of the sub assemblies that a modern printer comprises, and put them together with hacked code, and some good assembly skills (given appropriate tools in the workshop, of course). But nobody seems to be actually doing it, or to have done it.

There are some interesting ideas in the thread — for instance, instead of using ink/toner in a b/w printer (like a laser printer), the paper itself can be scorched black, or blackish.

There could be other ideas the makers of inkjet printers aren’t doing.

Even inkjets themselves (the printing heads) don’t need to be mounted only on an x-y assembly. They can be mounted on handles, and used to place ink on large or random sheets of paper, to create artworks on a massive scale. This has been done in the past, and publishing a project to do it again could be a very useful service to artists.

And there are probably a lot of ideas that haven’t been tried, in a world conditioned to think that x-y printers should print on A4 sheets of paper.

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Epson Ecotank printers are the nearest inkjet printers.

The problem is the head. Actually head and ink combo.
Printer heads are made by OEM component makers like Kyocera, Alps, Matsushita etc. Unless you have bulk orders or a very strong introduction to the OEM they will not provide any info or samples.
Once you have the info driving the head requires fairly complex electronics.
Designing from specs is time consuming and expensive. (Having designed fax machines from reading CCITT specs and a whole lot of OEM manuals ). There are several print heads available for assembly line label printing.
https://global.kyocera.com/prdct/printing-devices/inkjet-printheads/

It is definitely doable though. Over the past 5 years the cost of very powerful Cortex M4 microcontrollers has dropped to cheap hobby levels. This removes the need for a custom asic and parallelizes the process of software development.
One could easily 3dprint a good enclosure. OR even leave it wholly open.

The industrial printers are similar to Epson Ecotank machines without the housing and with large static tanks. Essentially you avoid moving the head and instead move the print surface along a conveyor while covering the print surface with a large number of heads to provide parallelism and speed. Dont know the cost of these industry standard heads.

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This describes the potential for making an inkjet machine. Even conceptually, inkjet machines are complex in principle, so much so that I suspect it drove the makers to jump quickly to the development of colour printers. Meaning, so much effort needed that the next step was worth exploiting quickly.

But that leaves the possibility of simpler single colour printing worth exploring, I should think. Making a prototype machine, slow, or even handheld, does not appear to be a path filled with hidden pitfalls.

Some thoughts:

  1. The printer head. This would be a cheap laser pointer. Work is needed to discover whether a more complicated lens is needed, in order to focus the light to the paper in sufficient intensity to char it. Once that is achieved, the amount of time to keep the light switched on needs to be controlled.

  2. The placement. A second laser pointer, placed perpendicularly to the first, coupled with a light sensing diode, can ‘read’ the x-y coordinates of the operating pointer relative to a piece of paper placed in a tray with mirrors at each corner. This is a simple computation.

  3. The ‘pen’ holder. This actually doesn’t need a major guidance system. Rather, the image file, translated as a bitmap, can be used to confirm that the pen has moved over all the points where a black point is needed on the paper. The holder is then a fairly simple jig that holds the pointer perpendicular to the page, and it can be lightly ‘scratched’ all around, pretty much randomly, to create the final image on the paper. An additional visual counter connected to the bitmap reader can inform the user what percentage of the image has been completed, or a full-screen display can describe visually what parts are omitted or incomplete. Of course, for pages of text, the user will herself know whether the print quality is acceptably readable, even when not fully printed.

I suspect that even if an RPi is dedicated to this tool, the total cost will be within Rs 5k, not counting the time and effort of the prototype maker, of course. But if the RPi is just being cycled through different jobs, then the overall cost will drop to a few hundred, max. I don’t know if an Arduino will be even cheaper.

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Charing paper with a dvd writer laser diode:

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A charming paper, indeed!

Considering that the maker recycled a regular dvd recorder, probably a broken one, and that the Arduino can probably be plugged in and out of the finished machine, his out of pocket expenses are close to nil.

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