Can Not Print files over 40 pages using duplex
 

I have a Dell desktop running Vista Ultimate to which I have added a
new HP7780 Officejet Printer. For some reason, I can not print a
file over about 40 pages using 2 sided(duplex)printing. There are no
errors. The spooler just stops thinking that it is complete. Have
tried it on another HP printer with the same result. Printing single
sided is fine. Printing from my HP notebook running Vista works with
no problems.

Sounds like some kind of timing problem since duplex printing
takes a lot longer. Does anyone have any ideas. Would really
appreciate any help.

Bob Hanlon