Homebrew PCBs

Hi,

Just dropping in to report my latest results using the Pulsar 
transfer paper, pic here:
http://groups.yahoo.com/group/Homebrew_PCBs/files/Pulsar/

Filename: Toner transfer smaller.JPG

I scratched at the bottom right with my nail and only a few speckles 
of toner came off.  This PCB is 3 3/4" square.  The connector in the 
center is 0.5mm pitch with 10mil traces leading into 20mil traces.  
Even the thin border line and super small text stayed on.  They 
usually fall off from being too close to the edge and not getting 
enough heat or pressure.

This was with a Konica Minolta PagePro 1350W laser printer and 
replacement toner from here:
http://stores.ebay.ca/TonerKits-SUPERSTORE

A refill for 6000 pages and chip costs $20USD, compared to $100-$125 
for the cartridge retail.  The printer initially comes with only 1/4 
toner capacity; 1500 pages.  The stock toner is very good, but this 
replacement toner is even better.

I've tried several HP printers and this printer/toner combination far 
exceeds anything I've gotten with the HP.  The only drawback is a 
slight skew in the image, but that might be because I'm printing only 
on the right side of the page instead of dead center.  Yup, I screwed 
up when I refilled the toner and put a tiny scratch in the center of 
the drum.

The problem with the skew is that the 2 sides cannot be perfectly 
aligned into a 'sandwich'.  I have to compromise a little and make 
the pads for the vias slightly larger, no big deal.  Then I slip the 
PCB in the paper sandwich and pass it through a H300 laminator about 
12-15 times; flipping the PCB each time through.

Robert
:)

On Thu, 06 Apr 2006 04:21:05 +0200, Robert Hedan  
<robert.hedan@...> wrote:

> Even the thin border line and super small text stayed on.  They
>
> usually fall off from being too close to the edge and not getting
>
> enough heat or pressure.

I have a theory on the "otline problem":

I notice a very small shrinkage when the paper cools after fusing. What if  
this shrinkage pulls the paper in and breaks the small outline off?

There is a simple workaround - i put another, wider outline around the  
whole board just outside the real one. Sometimes that will go partially  
over the edge of the PCB piece but that doesn't matter since as long as  
there is a little left it will protect the outline.

I find if i use a ground plane the effect is strongly reduced already,  
although sometimes flakes of the very outer edge get pulled off, so i also  
use a wider "sacrificial" outline here.

>
> The only drawback is a
>
> slight skew in the image, but that might be because I'm printing only
>
> on the right side of the page instead of dead center.  Yup, I screwed
>
> up when I refilled the toner and put a tiny scratch in the center of
>
> the drum.
>
>
> The problem with the skew is that the 2 sides cannot be perfectly
>
> aligned into a 'sandwich'.  I have to compromise a little and make
>
> the pads for the vias slightly larger, no big deal.


Get the service manual for he printer, skew can usually be adjusted out  
easily. There are normally two adjustments, one to turn the laser assy (to  
get a line parallel with the LE of the paper) and one to make the paper  
run straight (to get a line parallel with the side of the paper).

ST

I ran printing tests on ordinary laser paper and confirmed that the printer
has no skew.  I know what I did wrong.

Since I screwed up the center area of the roller (and some of the left
side),  I used only the right side of the printer.  And since I want to save
on transfer paper I cut it in 4 pieces.  Then I used an ordinary paper as a
carrier, folded the top of the piece of transfer paper over backwards,
hooked it on the right side of the carrier and scotch taped the rear of the
fold in place.

I bet the printer traction rollers pulled unevenly on the transfer paper and
moved it slightly off line.  I have to somehow secure the piece of transfer
paper properly onto the carrier so that it doesn't move.  I can't use tape
on the front 'cause the fuser will melt it and make matters worse.

I just made a test using only 1/2 a sheet of paper and the printer processed
it properly (just a couple blinking lights).  So I'll pass 1/2 a transfer
sheet and print only on the right side, not much else I can do.  At least
that way I'll get perfectly aligned holes again.  I can keep the unused side
for later, hoping that leaving it in the envelope will return it to a flat
shape (it curls up from the heat and jams if I use it again).

Robert
:(


-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@...m] De
la part de Stefan Trethan
Envoyé : avril 6 2006 02:07
À : Homebrew_PCBs@yahoogroups.com
Objet : Re: [Homebrew_PCBs] Update on toner transfer

...

Get the service manual for he printer, skew can usually be adjusted out  
easily. There are normally two adjustments, one to turn the laser assy (to  
get a line parallel with the LE of the paper) and one to make the paper  
run straight (to get a line parallel with the side of the paper).

ST




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http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
Yahoo! Groups Links

You can try to use a cheaper paper so it doesn't matter so much of you  
waste more, i use half sheets too.
To stick a smaller piece down you can use paper tape or laser printer  
labels, but this will always lead to increased paper thickness which means  
less toner density.

If your drum was not damaged you could probably set the printer to  
envelope printing or something to switch off the lights...

ST


On Thu, 06 Apr 2006 19:22:30 +0200, Robert Hedan  
<robert.hedan@...> wrote:

> I ran printing tests on ordinary laser paper and confirmed that the  
> printer
>
> has no skew.  I know what I did wrong.
>
>
> Since I screwed up the center area of the roller (and some of the left
>
> side),  I used only the right side of the printer.  And since I want to  
> save
>
> on transfer paper I cut it in 4 pieces.  Then I used an ordinary paper  
> as a
>
> carrier, folded the top of the piece of transfer paper over backwards,
>
> hooked it on the right side of the carrier and scotch taped the rear of  
> the
>
> fold in place.
>
>
> I bet the printer traction rollers pulled unevenly on the transfer paper  
> and
>
> moved it slightly off line.  I have to somehow secure the piece of  
> transfer
>
> paper properly onto the carrier so that it doesn't move.  I can't use  
> tape
>
> on the front 'cause the fuser will melt it and make matters worse.
>
>
> I just made a test using only 1/2 a sheet of paper and the printer  
> processed
>
> it properly (just a couple blinking lights).  So I'll pass 1/2 a transfer
>
> sheet and print only on the right side, not much else I can do.  At least
>
> that way I'll get perfectly aligned holes again.  I can keep the unused  
> side
>
> for later, hoping that leaving it in the envelope will return it to a  
> flat
>
> shape (it curls up from the heat and jams if I use it again).
>
>
> Robert

I haven't found a cheaper alternative to Pulsar transfer paper that gets
quality results.

I meant drum, not roller.  I just slightly touched it with tweezers to get
some lint out of the roller and that did the job.  It left miniscule
scratches in the finish and that was all it took.  Live and learn.

Robert
:(


-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de Stefan Trethan
Envoyé : avril 6 2006 13:34
À : Homebrew_PCBs@yahoogroups.com
Objet : Re: [Homebrew_PCBs] RE : Update on toner transfer


You can try to use a cheaper paper so it doesn't matter so much of you  
waste more, i use half sheets too.
To stick a smaller piece down you can use paper tape or laser printer  
labels, but this will always lead to increased paper thickness which means  
less toner density.

If your drum was not damaged you could probably set the printer to  
envelope printing or something to switch off the lights...

ST




Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
Yahoo! Groups Links

Robert Hedan(robert.hedan@...) is reported to have said:
> I ran printing tests on ordinary laser paper and confirmed that the printer
> has no skew.  I know what I did wrong.
> 
> Since I screwed up the center area of the roller (and some of the left
> side),  I used only the right side of the printer.  And since I want to save
> on transfer paper I cut it in 4 pieces.  Then I used an ordinary paper as a
> carrier, folded the top of the piece of transfer paper over backwards,
> hooked it on the right side of the carrier and scotch taped the rear of the
> fold in place.
> 
> I bet the printer traction rollers pulled unevenly on the transfer paper and
> moved it slightly off line.  I have to somehow secure the piece of transfer
> paper properly onto the carrier so that it doesn't move.  I can't use tape
> on the front 'cause the fuser will melt it and make matters worse.

I use Avery mailing labels, the sheets are made to print an a laser
printer and take the heat.

Wayne

-- 
Computer and car salesmen differ in that the latter know when they
are lying.
_______________________________________________________

--- Robert Hedan <robert.hedan@...> wrote:

> I ran printing tests on ordinary laser paper and
> confirmed that the printer
> has no skew.  I know what I did wrong.
> 
> Since I screwed up the center area of the roller
> (and some of the left
> side),  I used only the right side of the printer. 
> And since I want to save
> on transfer paper I cut it in 4 pieces.  Then I used
> an ordinary paper as a
> carrier, folded the top of the piece of transfer
> paper over backwards,
> hooked it on the right side of the carrier and
> scotch taped the rear of the
> fold in place.
> 

The 3-fold at the top is probably much too thick for
even traction. What I've had success with, on a
LJ-III, is to first print the board on normal paper,
cut a piece of photo paper to cover it with a good
margin and stick it on with white labels, then print
it again, taking care not to print on the label. The
white labels are more heat resistant than scoth tape.
Unless you're very careful when applying it, scotch
tape may come loose or melt somewhere in the path and
pretty much gum up the works. Spent a not-very-fun
Saturday afternoon finding this out.

As my heater/roller combo requires a rather long
"tongue" I've taken to cut a strip the width of the
paper and long enough to print the board. This seems
to make the printing more even, the drum and/or fuser
don't seem to take well to uneven thickness. Makes
sense, as envelopes and other narrow stock are to be
centered in the manual feeder.

- YD.


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