Does anyone still buy Versatec printers?

[Dave Martindale]

We have several Versatec plotters here and two Imagen printers, so I will
try to compare them for the benefit of the readers.

The Versatec requires little maintenance other than regular cleaning and
changing of toner, premix, etc.  It just sits there and runs until it
breaks.  The Canon laser engine requires having its drum replaced
occasionally, corona wires adjusted, and a number of other apparently-
finicky mechanical adjustments.  Imagen has been very slow in shipping
the specialized tools needed for these adjustments.  On the other hand,
day-to-day operation of the Imagen involves feeding it paper, premix, and
toner concentrate as it asks for them (there is a panel with LEDs indicating
which one is low) and clearing the occasional paper jam.  With the Versatec,
you have to monitor quality yourself, press the "premix add" button
when needed, and change the premix when you judge it's needed.

Output quality of the Imagen is clearly better.  The resolution is higher
(320 vs 200 dpi) and there are no gaps between dot rows where the
Versatec started and stopped, nor black smudges where the image was
overdeveloped due to the paper stopping for too long in the Versatec.

For Troff output, the Imagen seems the winner.  It is driven over a serial
line, and the scan conversion of the characters into raster form is done
in the Imagen, offloading the host.  The output is on standard 8 1/2 by 11
paper, in the correct sequence (the last page is printed first).  The
Versatec requires scan conversion to be done in the host, and the busier
the host is, the more problems you will have with uneven output quality
due to the Versatec pausing.

For graphics, the Versatec still seems to win, though that may change.
It is an extremely dumb device; you just pass it bits.  This makes it
easy to generate whatever image your heart desires.  Our first Imagen
was completely incapable of doing full-page graphics; it just didn't
have enough memory.  We have a newer model now, and have just upgraded
the older one (the upgrade instructions were not complete, we had to
call Imagen to find out that the two boards in the end slots should be
moved) and they are supposed to be capable of graphics.  However, we
don't have any software in place yet to do this.  Some machines run
the Berkeley VLSI tools; they already support the Versatec as an output
device.  I know of no such support for the Imagen.  I do not know if
the Imagen is even capable of doing full-page grey scale images, which
require individual control of every dot on the output page.  Certainly,
transferring this much information over a serial line will take forever.
The Versatec's DMA interface runs at the same speed regardless of what
is to appear on the page.

	Dave Martindale
	University of Waterloo