I have an old Kyocera FS-1500 over cups.

When i try to print, sometimes everything works. but most of time, it prints alright the first 2/3 or 3/4 of the page and then the rest of the page is blank, simply not printed...

To print it full, i have to print to a .ps file and print it through lpr or lp. sometimes it works with lp and sometimes with lpr, depending on document.
Sometimes it works directly from the program.
The worst case was today. I had to make a .ps file, which didnt work neither with lp nor with lpr. So i converted it to pdf with ps2pdf and printed it through acroread, which finally worked.

When I print from Windows through samba, everything's fine.

Anyone got an idea? Would be very nice, i wouldn't use so much paper anymore...

Have you tried going to linuxprinting.org and seeing what issues there are, if any, with your printer, or if there are substitute drivers?

Also, do you have page formatting issues? What are you doing differently (or even had been doing) when you have the problem as opposed to when you don't?

Moxieman