>I'd guess that it will need two identical toner cartridges and be
physically
>a little larger than otherwise similar performance machines.

I believe this is highly unlikely.  The web page says "duplexing at the
engine speed".  In this case the engine speed is probably measured in
"surfaces per minute" rather than "pages per minute".  The current crop of
HP printers duplex at less than half the simplex speed because it takes a
second or so to turn the paper around in order to print on the back side.
The LJ 9000 probably prints the front of the second page while the first
page is being turned over.  This means that the engine is not held up
waiting for the paper to turn over.  No magic and I'm afraid the speed isn't
doubled, but it *is* faster.  Xerox has printers that do this already, but I
think this is the first HP to do it.

Regards,
Rob

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *