Using another printer usb hp ... installed ... working ...
I found again usb type choice when adding printer, then I add printer with same hp choice, same usb, modifying text titles from hp to lexmark ... choosing then lexmark ppd: /usr/share/cups/model/Lexmark-Z600-lxz600cj-cups.ppd
the uri is now:
and going in /usr/lib/cups/backend$
now it outputs:
direct z600:/dev/usb/lp0 "Lexmark Lexmark 640 Series" "Lexmark Printer"
Still in place the usbfs mount in /etc/fstab .
PS: My system xubuntu / ubuntu 9.10 / 2.6.31-15-generic / i686 GNU/Linux
PSPS: during disconnecting lexmark I forced from synaptic reinstalling some cups* packets .... blocked system ... restart ...