Duplex printing stoped working after one of the recent updates.

Question

Hi,
For some reason my HP Laserjet P3015 stoped printing duplex. Some dialogs show the "beidseitig drucken" option and I can check this and get duplexing. But I configured duplexing in the HP printer settings and it is ignored. I had system settings from earlier times with the option enabled but they seem to not work any longer. So how do I set up a printer to print duplex from all applications?
Thanks for helping me saving trees!
Best
  Stefan

Answer 1

It is possible to set duplex as the default setting via CUPS - the core printing system used in OS X. Using a web browser you open an internal web page, select the printer you want to modify, make your changes and then save this as the default. Then when you print, this setting will stop you from having to access the driver menus.
But there is a caveat to this setitng being used and that is based on the application being used. If the application uses or involves the default print dialog in the print job submission, then you will get a duplex print job. But there are applications that bypass the default print dialog and will therefore submit the print job without the settings you have set. The Print icon in Word for Mac 2011, part of the MS Office 2011 suite, is an example of the print dialog and thus the default settings being ignored. But if you select File > Print in Word, this will invoke the print dialog and your defaults will be honoured.
To access CUPS, open Safari and type
http://127.0.0.1:631/printers
Note that for OS X 10.8, the CUPS page is blocked by default. To enable it, open Terminal and type "sudo cupsctl WebInterface=yes" (without the quotation marks). Enter the admin password when prompted and then refresh the browser view.
With the CUPS web page open, select the printer you want to modify. Then from the Administration drop menu, change to "Set Default Options".
This will show a new page with some menu headings (links). You may have to check each one but one of them will have the duplex (or two sided) setting. With the option selected you then need to scroll down the list to the bottom of the page where you will see the ‘Set Default Options’ button. Click this and you will then be presented with an authentication window. Enter the account name and password that has been set as the admin for this Mac. And then press the Log In button. You will then see another page stating that the information change is completed.
You can now check that the change has been successful by selecting to print this page from Safari. With the correct printer selected, change to the relevant menu to ensure you modification has worked.