Please do post your results.
It is something that bothers lot of people...
Ioannis
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I will do...but I'm one of those guys that needs the project to "talk to me" - no I don't mean I'm going insane, but now I've stripped it down, there appears to be several options & there's no clear winner at the moment...so rather than rush into it, over the coming days/weeks eventually one option will percolate to the top.Originally Posted by Ioannis
Quick option - have this printer print onto pcbs only (that would just mean raising the print head a little - easy)
Less quick option - convert this to a flat bed printer, where I can feed all manner of stuff below the print head. This would need a significantly different approach (much more clearance need below)...the roller 'feed' would need to be binned - a leadscrew would likely need t be the way etc etc.
the initial probem facing many conversions is that there's an optical 'paper detect' sensor - the printer feeds the paper in, but then backs it out a little until the leading edge of the paper is detected - it the proceeds to print .....now that's a great idea when printing on paper, but for pcbs...all the to'ing & fro'ing is not welcome.
so at this early stage, I can feel a pic being brought into the equation to spoof the optical sensor! (something that surprisingly nobody seems to have done - they mainly go low tech with a mechanical approach to spoofing the optical sensor)
Last edited by HankMcSpank; - 1st September 2010 at 11:49.
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Don't worry about the time this will take. I'll be subcribed to this thread for ever (sort of speak...)
Now about the sensor, why that bothers you?
If it works, leave it. I suppose it contributes to the initial position of the paper/pcb, right?
Ioannis
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If you have some sort of tray to place the PCBs on then the sensor could be used as a locator as it is designed to. Then when the etching is finished the PCBs could run again for the silks.
Maybe...
Dave
Always wear safety glasses while programming.
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At this early stage, I'm not even sure why it bothers me!
I know it's certainly appears to be a hassle for a lot of diy 'direct to pcb' printer conversions.....it's my understanding that it's only role is to find the leading edge of the paper - but the end goal here is near perfect repeatability & 'registration' - not sure how achievable that will be with a system that use friction rollers & an optical edge finder.
....but like I say, it'll become clearer in head the best strategy for me to pursue over the coming days.
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I do not like the friction too. And this technology is not suposed to have good repeatability. Every time the rollers move the paper/pcb/whatever, they are losing a little of their diameter. So it is sure that this cannot be very accurate.
Another idea might be to use the steppers that move the rollers, to move a table having the pcb on it. Difficult as there are no datas about the motors and the gear involved.
Ioannis
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Well fortunately this particular printer (Epson C66) appears to use a stepper for the paper feed motor, so in principle it should be just a matter of feeding those wires to either the original stepper but relocated to the front/middle of the printer driving a leadscrew (or use my own stepper - there's seems a little small!). Then just a matter of dividing the pulses to achieve the right feed rate.
I believe someone has done this (albeit with an HP printer) as I saw a youtube video relating to it.
The hour or so of dabbling to date....shows I'm in diffs already. Apparently the optical sensor has to be relocated very precisely to get the right timing - else the printer just gives a paper feed error. Hey ho!
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Ok, making some progress.
I've decided on the easy option - don't dick with the head height & simply feed 0.8mm copper into the printer! (no outlandish hacking needed)...
This is 0.8mm double sided copper....
So the procedure is...
1. Buy a secondhand epson printer that uses durabrite ink (this is pigmented ink & means your 'possible contender' printer is capable of doing direct to copper printing)
2. Remove just about all the paper feed mechanisms *except* for the friction roller which pulls the copper through)
3. Relocate the optical sensor to a more appropriate place (this was an earlier test using paper to establish how to spoof the sensor)...
(that's the optical sensor to the right of picture with the blu-tack holding it in place)
4. Tape a little bit of card to the copper (to spoof the optical sensor that it has found the paper edge)
An then reference this video for the actual feed sequence...
About 2 hours work in total (less now that I've done one & therefore know the shortcuts!)
Last edited by HankMcSpank; - 2nd September 2010 at 20:04.
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