Every time you submit a print request, CUPS creates a print job that contains information about the print queue to which you are sending the request, the name of the document, and the page description. Print jobs are numbered, for example, queue-1, queue-2, so that you can monitor each print job as it is printed or cancel the print job, if necessary.
When a print request is submitted, CUPS does the following:
Determines which programs to use (filters, print drivers, port monitors, and back-end programs).
Runs these programs to complete the print job.
Removes the job from the print queue when the print job is complete, and then prints the next print job that is submitted. You can configure CUPS to notify you when a print job is complete or if any errors occur during printing.