The real problem with laser printers and backup is that the paper
physically changes size between printing the front and back side. This
is especially true in high-humidity areas (like here on the Wet Coast
:).
I've measured 1/8" shrinkage. If you run the paper through once (and say
print something off in a corner), you get MUCH less front-back
misregistration.
I was a Principal Software Developer at Creo (they manufacture
Computer-to-plate imagers for the printing industry), and one of the
products I was involved with was called Digital Blueline. This is
proofing software for doing backup proofs. We had the ability to shift
the back page to optimize alignment with the front page, and once the
paper was dehumidified, backup was pretty good.
So having said all that, I don't see any problem getting backup on a
media which doesn't change size, espcially if you have the ability to
apply an external shift.
Doing backup with an inkjet should be MUCH easier.
--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/ > -----Original Message-----
> From: ballendo [mailto:ballendo@...]
> Sent: Thursday, April 29, 2004 2:31 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Re:laser jet consistency and registration
>
>
> Hello,
>
> In a previous life I was a copier service tech. Prior to laser
> printers, but as most know now photocopiers use the same process.
>
> We used to have a heck of a time with page registration, and I know
> the truth of Russell's comments below having adjusted many optics
> sets to<wards> 1:1...
>
> So I'm wondering, Has anyone taken the time to see if he or she can
> get a good back to back registration on PAPER?
>
> Because if you can't get the sheet of paper to reliably go through
> twice accurately; isn't it kinda unlikely that the mods to allow a
> board to go through are gonna improve things?
>
> Next, IF it is possible and likely for the registration of two passes
> to line up with respect to the board edges: Has anyone held this up
> to a light and checked if all the holes line up all across the board?
>
> For a eurocard sized board?
>
> Thank you in advance,
>
> Ballendo
>
> P.S. I was really getting gung ho about direct etch resist
> printing-- even posted awhile back about the CD tray printer
> I saw at Fry's, and
> was talking to avecia about their resist and soldermask, when...
>
> The above questions popped into my head. For me, if ya can't
> do two- sided, it's a no-starter. SMD and SMT are not going
> away, and they
> require two-sided layouts more often than not (means always<G>)
>
> I truly LOVE the idea. And with a print head on a cnc machine the
> registration problems go away... For others to take their place<G>
>
> But if I'm gonna have to TT the second side anyways...
>
>
> In Homebrew_PCBs@yahoogroups.com, Russell Shaw <rjshaw@n...> wrote:
> > The similar interests are to achieve the ∗end∗ result. I'd
> rather see
> > CNC discussions here than boring old laser printer crap
> which i know
> > is inconsistant between models and toner brands anyway.
>
>
>
> ------------------------ Yahoo! Groups Sponsor
> ---------------------~--> Buy Ink Cartridges or Refill Kits
> for your HP, Epson, Canon or Lexmark Printer at MyInks.com.
> Free s/h on orders $50 or more to the US & Canada.
http://www.c1tracking.com/l.asp?cid=5511http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/bGYolB/TM---------------------------------------------------------------------~->
Be sure to visit the group home and check for new Bookmarks and files:
http://groups.yahoo.com/group/Homebrew_PCBs Yahoo! Groups Links