Homebrew PCBs

DJ Delorie wrote:
> 
> The inkjet does the same thing, even though I know the driver isn't
> dithering it.  Apparently, the print head just can't shoot ink drops
> accurately.
> 


Thats what I have observed too. If you look at it under a microscope 
then you can clearly see that line edges parallel to the print head 
travel axis are much less jagged than line edges perpendicular to the 
print head travel axis. It could be that the droplets are not landing on 
the paper at the precise time. Maybe air currents play role here. It 
would be interesting to override printer control and allow the head to 
move 1/10th its normal velocity and see if it improves the effective 
resolution.

I'm sure most printers do not print at the resolution manufactures 
claim. I see pixelation errors when printing 6mil (0.2mm) lines from my 
Canon MP810. This printer is rated at 1200dpi (7 pixels in one 8mill 
line) yet I see some lines are significantly wider than others 
indicating the printer  software is down converting the image to a lower 
resolution. Normally the effect isn't major but visible under a microscope.
The image files in question are 1200dpi and do contains correct number 
of pixels.


Adam