Sciencemadness Discussion Board

New old printer

ignaro - 7-9-2004 at 07:19

Fax and similar raster printing devices are a little old: s XIX

There was a Paris-Marseille fax service: You wrote a note in Paris, put the paper in a big device similar to a mix of machine tool and pendulum clock, and in Marseille appeared a copy, in a similar device.
The printer had a metallic point which scanned the paper and could carry a weak current.
If the copy paper was moistened with a mixture of iodide of potassium and boiled starch, you got blue lines.
If you used a mixture of cyanide of potassium with hydro-chloric acid and a saturated solution of common salt you got dark blue lines; but in this case the writing point must be of iron or soft steel.
The iodide-starch copies has a short lifetime. The other copies has a long lifetime, but... well, i think that the reader has a short lifetime... Do you read this book http://www.mysteryguide.com/bkEcoRose.html ?

That was was a preamble.

I am searching for a non toxic composition for to humidify the paper, which must produce everlasting traces.

I want to develop a non appropriable design for a low cost printer-and-ink set.
A simple design which permits to build it in a no too high technology shop using standard non proprietary parts; an ink which can be prepared in a hobbyist laboratory using relatively easily available substances. It appears that humid paper and an array of conductive points could be a good method.
The aim is: An hobbyist could make the entire printer, for use or for sale. A high quantity of sellers and the possibility of build-it-yourself will prevent prices to rise. No programmed obsolescence, no artificially high priced parts or consumibles.
And I want to prevent device, ink, and enhancements from patenting or similar appropriation, all in the GPL spirit.

And maybe others pieces of hardware could be designed in this way...

(One) Cause for this initiative:
There is a lot of books and similar documentation freely available, but they are low cost on screen only, to print it is expensive, and the easy use of a printed book can´t be achieved on screen. Then, even if the author permits to print a book, a lot of people can't do it.

FrankRizzo - 24-9-2004 at 18:51

A bit off-topic, but if you can see it on your computer screen at home it's fairly easy to reproduce a copy even if the printing function has been disabled. Can you site a specific example of something that you have access to on-screen, but are unable to print out (assuming that you have a desktop printer)? I'm sure we can figure-out a way around the protection (through java-script disabling, screen-dump & OCR, etc).

Geomancer - 24-9-2004 at 19:49

Ignaro: concerning your goal of creating a printer cost competitive to commercial ones, you don't have a prayer. Regarding the chemistry, though, look into "vat dyes". These dyes have a transparent, soluable reduced (leuco) form and a colored, insoluable oxidized form. Normally, the oxidation can be effected by atmospheric oxegen, but perhaps a modified dye would have a higher oxidation potential.

ignaro - 27-9-2004 at 05:46

Quote:

Can you site a specific example of something that you have access to on-screen, but are unable to print out (assuming that you have a desktop printer)?


BSOD (Blue Screen Of Death).
The screen turns blue and a esoteric list of programs, routines and memory addresses is displayed, followed by a message "Call for tecnical asistance, ask the hardware vendor, pray, or whatever you choice. M$ don't care" :)

Seriously, I agree: if the system works and something appears on screen it can be printed... unless the author don't permits it by means of a simple clause "you can read on screen but you have not permission for to print it". It is not a technical obstacle, it is a legal, ethical or similarly abstract one.

ignaro - 27-9-2004 at 07:18

Quote:

Ignaro: concerning your goal of creating a printer cost competitive to commercial ones, you don't have a prayer.

Excuse me, I can't understand the meaning for "having a prayer"... :( Is it a colloquial expression?
Quote:

Regarding the chemistry, though, look into "vat dyes". These dyes have a transparent, soluable reduced (leuco) form and a colored, insoluable oxidized form. Normally, the oxidation can be effected by atmospheric oxegen, but perhaps a modified dye would have a higher oxidation potential.

Surely they are relatively low cost substances, it appears as useful.
I'll read about it.

ignaro - 1-10-2004 at 05:32

If I understood correctly, it is difficultly applicable:

Change (eventually made by the electric current) affects solubility only, then, it is necessary to rinse for extracting the remaining substance.