Mustek 600CP/1200CP/1200CP+ Print spooler interference problems

If your scanned images contain solid-colored horizontal lines (typically blue, green, and/or red parts), like in the picture below, this may be a sign of your print spooler interfering with the scanner driver.

It is possible that the print spooler is periodically polling the parallel port while trying to communicate with a (non-existing) printer. To verify that this is indeed the cause of the scanning problem, try shutting down the print spooler (usually cups) and make a few test scans. If no lines appear, it is almost certain that the print spooler caused the problem.

Another indication that the print spooler may be involved, is when the scanner appears to pause for a fraction of a second every now and then. This happens when the printer spooler blocks trafic to the parallel port.

How do you solve this problem, without having to shut down the printer spooler ever time? It's difficult to answer this in general, but for the Cups printer spooler, your best chance is to look at /etc/printcap. If that file contains an entry like this:

       lp|Generic dot-matrix printer entry:\
       :lp=/dev/lp0:\
       :sd=/var/spool/lpd/lp:\
       :af=/var/log/lp-acct:\
       :lf=/var/log/lp-errs:\
       :pl#66:\
       :pw#80:\
       :pc#150:\
       :mx#0:\
       :sh:
  

then try commenting it out and restart the printer spooler daemon. That should do the trick.

Thanks to Vasily Levin for providing this information.

Last update: $Date: 2005/10/15 10:48:17 $