printer problems

Larry Grover lgrover at
Fri Oct 28 13:20:33 UTC 2005

James Tappin wrote:
> On Thu, 27 Oct 2005 12:32:58 -0400 (Eastern Daylight Time)
> "KC1DI" <elbc2 at> wrote:
> K> Hi Larry ,
> K> Mine used to work in 5.04 also but when I Upgraded to 5.10 it will
> K> not longer work.
> K> I've done the set up several times Cups recognizes the printer just
> K> fine suggest the drive which is installed and when you send a
> K> document to the printer que it show up in the printer Icon. but never
> K> prints then just disappears.

One thing that may help figure out why your jobs are not moving from 
the queue to the printer is the cups error log.  Can you try the 

(1) Before you start a print job, open up a terminal window 
(gnome-terminal or konsole, etc), and enter the following command:

sudo tail -f /var/log/cups/error_log

and then enter your password, when prompted.

The 'tail' command with the '-f' option will continuously track the 
last several lines in a file; when used with a log file, it's a useful 
tool for debugging system problems (appologies for the newb 
explanation, if you already new this).

(2) Next, send a job to the printer.  It shouldn't matter what the job 
is, just about anything that should produce a little bit of printer 
output should be fine.

(3) Go back to the ternimal window, and wait watch the output.  You 
may see quite a few lines scroll by or maybe only a couple of lines of 
output.  If the print job fails, then at some point some type of error 
message should show up in the cups error_log.  Let us know what the 
error message says.  If you can't figure out which line or lines are 
relevant, just post the contents of the terminal window, once your 
sure the print job has failed and the log messages have settled down.

Hopefully this information will help us pin down the cause of your 
printing problem.

> I had a similar problem, I think the permissions and/or group assigments
> are screwed up -- when I changed the permissions of /dev/usb/lp0 to
> rw-rw-rw- the  queued jobs promptly appeared. (Probably not the correct
> fix, I think the real problem is that there is an lp/lpadmin group
> misassignment somewhere -- maybe someone else on this list can give the
> correct answer).

I had the exact same problem when I upgraded my system form warty to 
hoary (4.10 to 5.04).  Here's what I did to fix it:

I saw that /dev/lp0 belonged to the 'lp' group:
$ ls -l /dev/lp0
crw-rw----  1 root lp 6, 0 Oct 28 08:47 /dev/lp0

So I edited the /etc/cups/cupsd.conf file.  The section which needed 
editing was the Group section:

from /etc/cups/cupsd.conf:

# Group (Group)
# The group the server runs under.  Normally this
# must be lpadmin, however you can configure things for another
# group as needed.
# ex: lpadmin
#Group lpadmin

Group lp

The cups server needed to run under the 'lp' group, not the 'lpadmin' 

Your fix (making /dev/lp0 readable & writable by everyone) works 
(obviously) and is probably fine for a single user system, or system 
where all users can be trusted, but in some situations you would want 
to control who can use the printer.  In this case you would probably 
be better off changing the cups configuration so the server runs under 
the group which owns the device, or else changing the group ownership 
of lp0 to match the group that the cups server runs under.


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