Is there a utility to inspect the jobs that a printer has completed?
With CUPS (the standard printing system on Mac OS X, also used by many but not all other unices):
lpstat -W completed
CUPS provides a list of all jobs on a printer on its web front-end. Go to http://localhost:631/jobs?which_jobs=completed or whatever machine is hosting the print server.
That depends on which printing system you are using. When using CUPS you would like to have a look at the page logifile, which shows you every page that has been printed. The default location of that file is: /var/log/cups/page_log