All 3 of my thinkpads had Ubuntu 12 installed and my printer hp Officejet Pro connected to the router worked fine as a network printer. Now I installed Ubuntu 14.04 on all my computers and the printer will not be detected any more. I can only print when the printer is directly connected to the USB port of the computer.

I tried it with hplip and Samba. With Samba the printer is detected (procedure is very slow) but a testpage will not print. Msg:" unable to communicate with device (code=12).

Since Ubuntu 12 worked fine with network printers my question is what has changed in Ubuntu 14.04? What is missing? What can I do?

Juergen

From your current version 14 (it is using CUPS v. 1.7.2) try downgrade back to CUPS v. 1.5.2. I have had this problem too at Cups version 1.7.2 and I made the same solution. It worked at least in my case.

Later, though, I found out that I was able to print at version 1.7.2 by manually defining the IP of the printer-(or its server) at the /etc/cups/printers.conf. I just happen to hit that solution in the middle of my confusion.

Hope it helps.

Thank you for your help. I looked into printers.conf.
There is a line stating

Device URI:smb://userassword@WORKGROUP/router/Officejet%Pro%208500%20A909a

Explanation to this line
user = my defined user ID
password = my defined password
router = correct name of my router (not the IP)
My HP Officejet Pro printer is always quoted that way, seems to be right.

The problem is during setup the printer will be found but it won't print stating "NT status disk operation failed opening remote spool

If the printer is found by CUPS but it won't print, probably that is a "cups version vs. printer driver version" mismatch. As I said try downgrading to next lower but stable version which is cups v. 1.5.2. Just try, anyway you can reinstall v. 1.7.2 anytime after if the same problem recurs.

Hope that helps.

I had the same problem with hplip, turn out my firewall kept hplip from seeing the network printer, might be the same with CUPS.
I just temporarily stop the firewall and run hp-setup then start the firewall.