On Sat, 13 Dec 2014 23:35:24 -0600, you wrote:
>Yes you have absolutely right, but drums are wasted with the toner cartridges all the time. And also what kind of photo resist is used on those drums. They warn always to cover them for light when servicing. And the laser could be replaced from IR to UV, it is all maybe just dreaming, that is why I posted it here so the smart guy's can wake me up ... LOL
Ok, there's no photoresist on the drums. The drum used to be coated
in a selenium compound (that's one possibility), it's not something
that you can remove, nor is it intended to be a photoresist.
The photoresist is a substance that becomes conductive under the
influence of light, is an insulator otherwise. The drum is charged to
several thousand volts. The laser writes on the drum surface causing
the photoconductor to allow charge to migrate to the surface of the
conductor. When the laser moves to the next spot, the charge remains
if there's any. It's that charge that attracts the toner.
I have utterly no idea what the photoconductor is, but it certainly
does not work the way a photoresist does (polymerizes or breaks apart,
depending on the resist type). I don't think it's made to be removed
easily.
Exposure to excess light will likely change the sensitivity of *part*
of the drum, and give you uneven results when printing.
>
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>Another Idea that came into my mind stems from the old matrix printers. If a small heated punch 0.2 mm would tap the surface of a copper clad, covered with toner, would that be sufficient to make the toner adhere to the copper. Then when the whole pattern is done. Clean the rest of toner and drive it to the fuser from a laser printer ( external setup ) to fuse the toner extra on the copper.
You'd have an easier time spraying resist on the board from an inkjet.
The resolution of a dot matrix printer is pretty poor.
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>My first test with my hacked laser is to intercept the paper coming from the drum, before the fuser, combine it with the copper board and drive it true the fuser, That will be setup externally, but controlled from the laser. ( needs new timing setup, and sensor masking.
It might be a bit nicer if you could print directly on the board
itself.
Another option is simply to use another laser fuser as a substitute
for a laminator, but then you have the problem of removing the paper.
Harvey
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>A lot of idea's but yet not a pcb ... LOL
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>cb
>On 12/13/2014 5:41:52 PM, Harvey White madyn@... [Homebrew_PCBs] <homebrew_pcbs@yahoogroups.com> wrote:
>
>On Thu, 11 Dec 2014 15:01:26 -0600, you wrote:
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>>Hi all, pcb making methode thinkerers,
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>>You all know that the basic concept of a laserprinter is that a laser writes a dotpattern on a electronically charged photosensitive drum. Toner is then attracted to that pattern which is reversed in polarity by the light of the laser. Next the transfer and fusing to the paper gives us the crisp copy's we all like so much.
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>>Now, and this is probably for the engineers among us, could it be possible to make the copper clad board the same photosensitive surface and let the laser write directly on it. Then apply toner on it, and fuse the toner. Then a bath in photo resin desolver where the unprotected surfaces will be cleared from resin and the pattern with toner stays. Then etching and remove toner. For solder mask there are good systems on the market.
>>
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>Hmmm, the copper is not photosensitive. To make it photosensitive,
>you'd need a special kind of coating which is the same as on the drum.
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>What the conventional laser printer does is to transfer the charge
>pattern on the drum, which you know, and then transfer the charge
>pattern to the paper, then fuse that to the paper.
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>There's no good way that I know of to make the board photosensitive,
>other than to coat it in photoresist.
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>That would be the same as a throw away sensitive drum for each board.
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>If you mean to coat the board and write on it with a laser, that has
>been done, however, the laser in a printer is infrared, the laser
>needed to expose photoresist is ultraviolet, if not just plain blue
>(depends).
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>I think that the average photoresist cannot "see" the infrared laser,
>and as such, cannot be exposed by the laser in the printer.
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>Had you a different idea of how this would work?
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>
>Harvey
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>>
>>Wonder what it would take to alter a laser printer to do something like this?
>>Would it be possible anyway?
>>There is a guy who had already rebuild his E 230 lexmark to print on pcb, but he did not used the fuser.
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>>I myself try to do the same with a hp 4100 but all I did so far is broke it down...LOL
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>>I keep you posted of my progress...
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>>camillus
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>>
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