As I had printing problems with my Lexmark X6170, which I bought at the time because it looked a good deal, I started to work on a solution.

I think this problem is also applicable for a number of other printers. The symptom is that the spooler in windows displays a progress for 99%. If you want to delete the job from the queue, you could end up restarting the print spooler.

The solution is rather simple (it took me a while to find out though).

If you go to the properties for your printer and click on the tab <advanced> and on the button <print processor>, just select the [winprint] processor instead of the manufacturer processor (in my case lexmark...). In the right pane select one of the [NT EMF...] processors and this should do the trick.
ALSO disable the bidirectional support on the <ports> tab...

As I thought the problem lies in the signal which has to be send back from the printer to the processor that the job has finished. As there is now way for the printer to send back the signal over the same printing port (RAW/9100), the spooler still thinks the job hasn't finished.
I searched the technet site and found some notes where a similar problem is described. In the case a problem like this occurs (apparently only with printers which use their own software and need bidirectional support...) they (the dark side) advises to use a Microsoft driver instead...

Hope I could help somebody with a frustrating problem.
(ps. printer works fine, the lexmark software not.)