I use different printer:
DELL 3100CN via LAN - no problem at all. Dell is very easy get work

HP LaserJet 700 MFP 775dn: multifuction document center run via LAN. This has been a nightmare over weeks.
I had tried different driver. SUSE support tried to help, HP support tried to help....
I found out, the printer work fine with USB. So driver must be ok.

The trick (this is valid for many HP printer and other modern printer with communication)

is here:

HTML Code:
http://hplipopensource.com/node/375
OpenSUSE

Avahi
Go to Yast Control Center and click on Firewall.
Select Allowed Services on left hand side pane.
Click on Service to Allow drop down which will show list of services we can enable using this firewall utility.
To allow avahi to discover the devices through hp-setup utility select Zeroconf/Bonjour Multicast DNS and select Add from drop down.and click on Next at the bottom right corner.
The OpenSuse Firewall Utility will display Firewall Conguration Summary. Click on Finish to compelete the process.

mDNS/Bonjour
Go to Yast Control Center and click on Firewall
Select Custom Rules on left pane, select Zone as External and then select Add at the bottom. A pop up will appear . Provide the values of the parameter as : Source Network 0/0, Protocol UDP, Ports 5353
Click on Add at the bottom right.
The OpenSuSe rewall utility will display Firewall Conguration Summary Click on Finish to complete the process.

SLP
Go to Yast Control Center and click on Firewall.
Select Custom Rules on left pane, select Zone as External and then select Add at the bottom. A pop up will appear . Provide the values of the parameter as : Source Network 0/0, Protocol UDP, Ports 427
Click on Add at the bottom right.
The OpenSuSe rewall utility will display Firewall Conguration Summary Click on Finish to complete the process.

Open these ports in internal zone, the printer works.