We have two Sharp MX-2310U network printers in our office building. They're both in the same subnet, and both set up in the print services console on our file & print box (Server 2008) with the standard Sharp postscript driver. Energy saving settings are identical for both units, and yet one of them is showing up as "offline", both on the print server and to any client PCs that it's set up on (a mixture of XP and Win7 clients).
The weird part is, jobs that get sent to the "offline" printer still get printed! Does anyone have any idea why this might be? It's not much of a problem, as most of my users don't even notice the status, but it's definitely bugging me.
As mentioned in the comments, check the SNMP setting. In Windows 7..
In my case, I changed the SNMP community. In your case, just try disabling it and see if that helps.