HP 800 inked area problem

Our office has recently moved from a bigger firm, where we were
using AutoCAD 2000 with a 42" HP DesignJet 800 PS. Now, we are
using a 42" HP DesignJet 800 (no PS) and AutoCAD 2005. (the plotter is
plugged directly to our ethernet network)

We use 36" paper rolls (913 mm wide).

We had the habit to use custom paper size of 910 mm x 2000 mm,
relying on "inked area" option to get the printer to cut the paper
right after the end of the real drawing. It worked perfectly 99% of the
time in our previous setup.

Now, it doesn't work anymore, and the plotter shows strange behaviour.

If the drawing's real height is less than (approx.) 40 cm, it works fine.

If it's higher,
- the printer starts humming (normal),
- countdowns a rather long (30 secs with a very simple drawing)
HP/GL processing,
- the head carrier makes *short* (1 cm displacement) moves, as it was
printing but without going all the way along the paper. It can last
a long time.
- then it starts printing
- and finally unrolls the full custom height of paper, regardless of
"inked area" being set both on the plotter and in the .pc3 file.


The problem isn't linked to drawing complexity, it even happens with 2
lines !

Any ideas on what's happening ?

J. Moosen