HP wireless settings the problem?
Hi, i'm looking into buying one of these printers, having a peep about it would seem that the problem you are having is an issue of HP rather than Linux. I'm just a user so can't offer a solution but may be able to point you at something you've not tried yet?
From a post elsewhere for an HP C4380
"There does not seem to be a way to statically define the IP address for the WIFI port. It gets a DHCP address from my WIFI router and then configures a printer to that IP address on the PC. Then you don't use the printer for a while, the DHCP lease is lost and next time you get a different IP address. You then have to change the PC printer port to the new IP address. My linksys router has max 9999 hrs for lease. Not very well thought out HP!"
This guy i think is using Windows and not having one myself i can't vouch for the accuracy of the info.
If the printer requires access via your computer (?) then perhaps your PC should be on attached to router with a static address (?) Sorry all guess work from me!
Hope you sort it though