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Subject: Re: Printing resist directly on PCBs

From: "Steve" <alienrelics@...>
Date: 2004-03-03

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@g...> wrote:
> On Wed, 03 Mar 2004 12:35:38 -0500, Alan King <alan@n...> wrote:
>
> > Steve wrote:
> >> --- In Homebrew_PCBs@yahoogroups.com, Alan King <alan@n...> wrote:
> >>
> >>
> >>> The Alps printers are full page, discontinued but plenty of them
> >>
> >> kicking
> >>
> >>> around for decal use.
> >>
> >>
> >> Someone already tried. The heads are only designed to print onto
paper
> >> so they just don't put out enough heat, the copper sucks heat away to
> >> quickly.
> >
> I dunno, but i had not the impression that hp bubblejets actually touch
> the surface.
> this is rather impossible because of two plastic "spacers" on the
side of
> the nozzles...
>
> so how should they cool the nozzle?
>
> i think the nozzle gets hot any any bad ink hardens.
>

You are getting confused. We were talking about Alps for those above
statements, and Alps are not inkjets. They are wax thermal (and dye
sub but we're ignoring that as useless for this) which use a ribbon
with a thin layer of wax that moves past a head that consists of tiny
heating elements. When they heat up, the wax is melted to the paper.

In an Alps (or any other ribbon based wax thermal printer) the ribbon
is scrolled at the same speed as the head so there is no apparent
motion between the ribbon and the paper. The head is pressing the
ribbon onto the paper.

But with a sheet of copper, the head elements just can't get hot
enough to reliably transfer the wax. Alps print-heads are already very
fragile so bumping up the head is not an option.

Steve