Homebrew PCBs

matt clement wrote:

>okay after doing some reading, it looks like the laser printers 
>spray a charge onto the paper and the toner statically attracts to 
>the charged spots.  therefore using a copper sheet will redistribute 
>the charge.  looks like a laser printer wont work, but i did see 
>some people use an inkjet printer directly on copper.
>
>matt
>
>  
>


  They depend on the high insulation properties of paper to hold the 
charge, and it's induced by the corona wire.

Yes copper will redistribute the charge.  Instead of inducing a charge, 
directly contact and give about what's needed at the drum. 

Might want to look back at the discussions Stefan and I had last year or 
so on it, probably everything you're likely to hit anytime soon and then 
some..

End conclusions:

  Tape your board edges, and with reasonably good surface you're not 
scratching your drum, or not much.  Cost of doing easy prints is maybe a 
toner cartridge sooner rather than later, $20 now and then.

  My HP6L prints great onto large areas of aluminum foil taped to a 
page.  Get wrinkles from not being attached, and flakes off here and 
there from being too smooth and also flexible.  Way, way better than I 
expected to print on straight metal.  Transfers rather well, metal beats 
the heck out of paper for getting heat to the copper.  Thin copper sheet 
and adhere to board would probably work fairly well for me, but other 
things do well enough and haven't worked on it too much beyond tests.

  With mods for straight board and keeping the right weak charge on the 
copper, it's likely it will work, at least on my 6Ls.  Even straight 
path printers aren't straight, major work required on the path for the 
board.  TT works ok enough, so while it'd be great and I have extra 
printers at hand for it, it's still a very back burner project.

  Heck not too much point reading the old discussions now.  That's where 
mine was at, and I think mine was going as well as anyone's trying it.

  Feed direction alignment is easy enough, do it optically at the same 
point on the board edge, and top and bottom should be aligned well in 
the feed axis.  Other axis would be mechanically aligned, but still 
should be able to get it pretty good too.

Alan