HP Officejet J4580 Shared Network Printer using CUPS not working

[Mogweh]

I have 2 computers, both with 11.04 installed and both with fixed ip addresses.

Computer A has an HP Officejet J4580 connected to it. Computer B is trying to print across the network.

I have set up computer A's driver using CUPS installing 'HP Officejet j4500 Series, hpcups 3.11.1' driver and it works well (locally). When I try and install a network printer on computer B (using CUPS) I get the option by "Discovered Network Printers":

HP Officejet J4500 series @ ComputerA (HP HP Officejet j4585 All-in-one Printer)

No idea where it is getting the j4585 from! I select it and install the j4500 driver exactly like I did on computer A and print a test page and I get a popup message:

Printer 'HP_HP_Officejet_j4585_All-in-one_Printer': 'com.apple.print.recoverable'.

closely followed by:

Printer 'HP_HP_Officejet_j4585_All-in-one_Printer' may not be connected.

I used to have the printer connected to Computer B and could happily print across the network from computer A using CUPS.

Any ideas what I am doing wrong?

Thanks