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Subject: Re: [Homebrew_PCBs] the naked truth about Laser Jet

From: Hans Wedemeyer <hans@...>
Date: 2003-07-04

Russel,
OK I said no more, but as you are asking serious questions here are the
answers:



> > Results are very good. Clear space between the pins, I can etch this
>
> > size no problem.
>
> I assume you mean very few if any shorts between pads?
>

ZERO shorts, I got two short when I tried to put (silly idea) the 2.5mil
trave between the 8 mil spaced pads... Can't do that

>
> I get sharper results by using spray-on PRP positive resist because
> the
> plastic coating sheet on pre-coated boards causes more undercut with a
>
> close-in uv light source.
>

As I said get to know your ligth source, and it appears you got to know
yours. the UV lights close up will casue scatter.
I use a bulb at 6 inches and it is god enoguht to NOT casue that
problem.
Also the shortened exposure time will help prevent that also. With
these 500Watt bulbs I expose for 70 seconds.

>
> > I still think there has to be a reason so many people are dumping
> Epson
> > Inkjet printers for $5 ! as you are referring to eBay.au I assume
> > Australian dollars...
>
> I've seen similar prices on US ebay too. Most users want to print
> photos
> sharper or faster (USB) and new printers are cheap.
>

Ok... My two inkjet USB is no faster that the LPT1 version, just more
convenient. I agree Inkjet are wonderful for phot printing...

>
> I've used laserjets, but the results were hopeless. What model is
> yours
> and how old is it? Genuine toner?
>

The first one (now retired) was a HP LaserJet 5L it did excellent PCB
work. The two I have now are both HP LaserJet 1100
One is used to clerical work the other is for me and my stuff.

Ink jet's are HP DeskJet 1220C(for schematics B-size and Yes... D-size
(two halves) ), HP 932C (the work horse for photo's), and the third one
is HP Photo Smart Photo Printer (six color) . The Photo printer could
have been a nice printer, I convinced this is one of the worst HP
products I have ever owned. The cartridge connection assembly is so
poorly done, rubber pads behind flex printer) , HP has to be ashamed of
it... I still have but hardly use it anymore, my old Fargo Premier
Photo printer, it uses dye sublimation. If you have ever seen this in
action it's a strange beast... resolution 144 dots per inch ! however
the results are as good as wet processed photo's from film, truly photo
quality. I know, can't be with only 144 dots per inch.... as I said
"strange beast".... but it really works... also costs US$2 per sheet of
paper and add to that the dye film comes to about $4.75 per 8" X 10"
still cheap . Today we are all locked into dots per inch as the only way
to judge photo quality, well... dye sublimation has been used to make
TechniColor (spelling) films since 1930's and is a wonderful process...

OK now I am shutting down, I don't have anymore time for this. I have
nothing against Ink jet's but just remember if you had a bad experience
with Laser, that doe snot mean every Laser user has the same....

Best Regards
Hans W



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