Operation Manual

back-end determines how many unsuccessful attempts are appropriate until the data
transfer is reported as impossible. As further attempts would be in vain, cupsd disables
printing for the respective queue. After eliminating the cause of the problem, the system
administrator must reenable printing with the command cupsenable.
13.8.7 CUPS Browsing: Deleting Print Jobs
If a CUPS network server broadcasts its queues to the client hosts via browsing and a
suitable local cupsd is active on the client hosts, the client cupsd accepts print jobs
from applications and forwards them to the cupsd on the server. When cupsd on the
server accepts a print job, it is assigned a new job number. Therefore, the job number
on the client host is different from the job number on the server. As a print job is usually
forwarded immediately, it cannot be deleted with the job number on the client host This
is because the client cupsd regards the print job as completed as soon as it has been
forwarded to the server cupsd.
When it becomes desirable to delete the print job on the server, use a command such
as lpstat -h cups.example.com -o to determine the job number on the
server, provided the server has not already completed the print job (that is, sent it
completely to the printer). Using this job number, the print job on the server can be
deleted:
cancel -h cups.example.com queue-jobnumber
13.8.8 Defective Print Jobs and Data
Transfer Errors
If you switch the printer off or shut down the computer during the printing process,
print jobs remain in the queue. Printing resumes when the computer (or the printer) is
switched back on. Defective print jobs must be removed from the queue with cancel.
If a print job is defective or an error occurs in the communication between the host and
the printer, the printer prints numerous sheets of paper with unintelligible characters,
because it is unable to process the data correctly. To rectify this situation, follow these
steps:
Printer Operation 213