HP inkjet printer kicks out environmentally friendly circuit
By Darren Murph 
posted Apr 19th 2007 12:08PM
posted Apr 19th 2007 12:08PM
It's been nearly three years since we first reported on printable circuit boards, but researchers in the UK are still working to hone the process. Leeds University's Seyed Bidoki was recently able to load a "standard Hewlett Packard inkjet printer with a solution of metal salts and water" and print out an actual electronic circuit. The mysterious "silver salt solution" and vitamin C mixture could be used to "pave the way for safer and cheaper electronics manufacturing," and moreover, this cheap and easy alternative should certainly be a hit with the environmentally conscience crowd. This method utilizes a water-soluble base, which differs from the less green solvents used in polymer ink / graphite paste varieties from before, but even individuals working with the project admit that ousting the current regime will be difficult. Still, the crew is pressing forward with this toxin-free approach, and hopes to elicit the help of "industrial jet printers" before long to speed things up.
Leeds Uni! Got an offer from them actually, going York instead...
I wonder how you'd solder onto the paper...
idiots... if you payed attention, you'd realize that the letters are BACKWARDS which means its a transfer. you probally iron it onto a blank board.
idiots... if you payed attention, you'd realize that the letters are BACKWARDS which means its a transfer. you probally iron it onto a blank board.
Don´t throw a glass of water over it my friend!!!
This will have no effect on how cheap electronics are, only on "homebrew", small scale efforts.
Just like Scholastic doesn't print Harry Potter books with inkjets, large-production boards will never be manufactured like this. And thus, the electronics you buy will not change from this.
Now, if you want to make your own board, this could make a huge difference. Right now your options for a 1 off board are limited and generally more expensive than this.
So... I can eat the circuit without getting poisoned but getting vitamin C instead? Awesome.
1: Read the actual paper:
http://www.iop.org/EJ/abstract/0960-1317/17/5/017
2: THEN look at the pictures.
3: Post politely.
Truth is this is only a "process" for depositing silver particles. Paper was used in the experiment, but any flexible substrate can be used. My coment was made in jest. Yours in ignorance.
If you actually *read* the article, you'll see that the "mysterious 'silver salt solution'" is simply silver nitrate, which is readily available from chemical supply houses—it's the basis of photographic film (or used to be, I suppose).
If you're interested in the details, the New Scientist article links to the journal where it was published, where it's currently available for free (with registration). There's enough information there to do it yourself—although it may not be cheap; I priced silver nitrate and ascorbic acid at Sigma-Aldrich, and found it'd come to something like $250 to fill a cartridge.
DAMNIT - that stack of papers you threw out was MY COMPUTER.
From what I gather from the research paper, the current system produces traces with only 3% the conductivity of current copper traces. It's a start, but we're not going to be printing circuit boards on t-shirts with our Deskjets anytime soon.
@blackfeather - when working with printed electronics, we generally use conductive epoxy - so our work doesn't go up in flames! Also, it can't be printed on just any old paper - because it uses a sputtering method, and needs to maintain a good conductivity, then usually specific papers/substrates are used (smoother ones, such as clay coated paper, to allow for less break-up between conductive particles).
@why not the LS2/LS7 - although this process is designed for inkjets (which as you correctly state, is only really feasible for small scale projects), there are a few other processes being developed which utilise offset-litho printing, designed for a much larger manufacturing scale.
Fraggle
Give this technology some time, when used with a colour printer each "colour" could be a compound with different elecrical properties allowing many components to be fabricated as part of the board. I can easily see how resistors, capacitors and simple semiconductors could be formed, the potential is stunning.
And after you print one or two layers of the silver nitrate/citric acid, you then dip it into a solution of copper sulfate and electroplate some copper onto it.
done and done.