We recently fixed the connection from Gary’s iMac (OS X 10.10) to a network connected photo printer, a Canon iPFS 5100 which uses 17 inch wide roll paper. Gary tried to print several times which failed but left the print job “stuck” in the print queue on his computer. When we finally got the connection working, and that printer is an SOB to use but it prints really well, the old stuck print jobs came spewing out of the printer. If you have ever bought photo paper and ink, you know these items are very expensive and it’s maddening to watch them being consumed on unwanted prints.
OS X, as you likely know, has a full fledged Unix system at its core. The Unix/Linux printing system is called CUPS, and it’s pretty well hidden from the OS X user interface. But with a bit of command line magic you can recover access to it. Here’s how.
1) open Terminal, the command line interface to your iMac.
2) type in exactly the following line (or cut and paste from here) and then press return
sudo cupsctl WebInterface=yes
it will ask for an administrative password
3) close Terminal
4) open a new Safari window or tab, enter http://localhost:631
5) you now have the CUPS web interface. bookmark it.
6) click the Administration tab, then manage printers, select the one you want. You can then see and cancel print jobs.