🚀 go-pugleaf

In article <13530@pasteur.Berkeley.EDU>, oliver@fire.berkeley.edu writes:
> About a week ago, I posted a question asking about low-end Postscript
> printers.  I was particularly curious about the QMS PS410, the TI
> MicroLaser, and the Printer Works JetScript/Canon engine combination.
> 
> 
> So, I'm still not quite sure whether to get the TI or the QMS.  I'm leaning
> towards the former because it is small and a bit cheaper, but I have been
> left with a very good impression of the 410 and I may go ahead and spring


I think that I'd ask whether the TI is a black or white writer.  The 410, I
belive is a black writer.  The diffrence in output is subtle, but important.

A blackwriter generates black dots everywhere the laser hits the drum.  The
normal unexposed drum will generate a white page.  The whitewriter on the
other hand REMOVES toner everywhere the beam touches the drum.  Now, since
lasers are essentialy round rather than ssquare pixels, you have to somehow
fint a round dot in a square (1/300th inch) spot.  There are 3 ways to do this.
1.  Make the dot stay within the bounds of the square pixel.  Draw a box, with
a dot in it that just touches the inside edges of the box.  2. expand the
dot a bit, so that it stays INSIDE the box at the corners, but bulges outside
of the box at the 4 edges.  3.  Encompass the entire box with the dot.
Most blackwriters use number 2 and adjust the toner, charge, and laser such that
the small unexposed diamonds between the dots will fill in anyway.  (draw 4
circles so the edges all touch, and you will see the diamond that I am talking
about here.  This will not work with a white writer.  You wind up with little
thin black lines etc over your page.  For a white writer, you have to use
option number 3.  This has the effect that a single row of pixels will have
nibbles taken out of the side.  You can get some graph paper and prove this
quite easily.  The bottom line, is that a whitewriter tends to have intense
solid blacks, but often times single pixels won't image properly.   3, 4 or
5 point type for example, TImes-Roman wiil have open spaces at the top and 
bottom of things like o's and e's.  In general, for find detail you want
one of the blackwriters.  If you are going to be doing something like creating
silkscreen masks, where the screen is say 150 mesh, then the loss of fine
resolution won't matter, because you need the solid blacks more than
the resolution.

Cheers
Woody