1st of all: printer is Xerox Phaser 3117 (laser, 8mb buffer, 600dpi, without automatic duplexing), running on Kubuntu 9.04 (...)
SlipX v. 2.0.0
Observations printing from pdf reader Okular.
Always printing with options "Duplex Printing - Short Side" and "2 pages per sheet".
When printing 100 document pages (25 sheets), the pages printed on the first side come out alright. Lights go red, waiting for a response. I put the pages in the feeder, hold down The Button (the only button the printer has, which is intended to switch printing mode between Saving and Normal) and the printer continues the job for only some pages. Then it hangs, and lights go green blinking. According to the printing manager, the job is "in process". So i have no option rather than cancel the job and restart the printing (and throw some sheets or print them manually)
When printing 40 document pages (10 sheets), the whole process happily ends without complaints.
My Conclusions: After printing the first side and sending some "pause" signal to the printer, her buffer is filled with the "other side" information to go on printing after pressing the button. It seems that when the printer buffer is full some bug causes the printing job to hang; leaving the printing job uncomplete, since the only left to print is what the printer buffer has.
Maybe my conclusions are totally wrong.
I would like to suggest one of two possible solutions:
A- Make the duplex printing even more "manually":
1.Print the first side,
2.Don't send a pause signal to the printer,
3.Make a message come out indicating the user what to do and put a "Next/Continue" button to go on,
4.Print the other side of the sheets.
This will also make the printing process in Linux less "test/error, let's see what happens if..." and more intuitive. [which, by the way, is what HP win-drivers work]
B- Check what happens after the pause signal, and/or after the printer buffer is filled as well. See what makes it crash.
Thanks a Lot for paying attention to this bug :)
Sorry if something isn't clear. English is not my default/native language.
Nicolás from Salta, Argentina