Konica Minolta Bizhub C200 Hangs.

I have a Konica Minolta C200 that hangs when connected to the network, after aprox. 5 min. Connected by USB it works well but I can't use the scanner.
I have tried it to several network connections, also tried to connect directly to a Laptop but allways hangs after a while.
Connected by USB to a Windows 7 (X64), the scanner doesn't operate with the Twain driver installed.