Radra wrote:
> Have you had the opportunity to examine your artwork transparency
> (mask) using a microscope? I wonder if it is better than mine. Wish
> I had some way to take a photomicrograph so I could post a photo.
>
> I was having some difficulty during the developing process. Some
> areas where the resist was supposed to dissolve away were not
> becoming completely clean. Assumed it might be due to the dark areas
> of my mask not being sufficiently opaque to UV. The dark areas
> actually appear grey, not black, when held up to a light. So I
> overlaid two masks to increase effective opacity. Placed the toner
> side of one mask against the toner side of a mirror image mask. The
> down side of this technique is that the toner image is now 4 mils
> away from the PCB due to the transparency thickness which, as you
> observed, will degrade resolution; but the resulting PCB was
> acceptable. In retrospect, I now suspect I did not have to overlay
> the masks, but instead only needed to improve the developing process.
>
> So the question I now have is "Does an inkjet printer produce better
> masks than does a laserjet printer?".
Only if the inkjet transparency is decent stuff ∗and∗ the ink is compatible
with it ∗and∗ it's not a crappy printer.
If the ink is incompatible, you usually get pinholing, slow drying, and
sometimes smudging. Crappy printers are slow drying, leave streaks, and
smudging anyway. Decent printers can be a cheap base model (like an epson
stylus 400 color, long discontinued). I've found epsons better because they
use piezo-mechanical ejectors on room-temperature ink, and the ink is absorbed
into the gelatine coating of epson transparencies which dries really fast.
Other slower-drying printers and non-genuine ink/film combinations can
give decent results, but you'll have to experiment to find the right ones.
Laser printers often give dark edges but not-very-dark interiors when
printing larger areas. The heat can deform the printout, depending on
what it's made of. Laser printouts are always grainier and can show more
pinholes if you change to a new cartridge with different toner.