USB printer goes off-line regularly in windows xp

Hi,
I have a Lexmark E321 printer connected through USB
I just like to tell you that my printer goes off-line regularly, I have updated service pack 1A and did a Bios update on the computer as well as install the USB 2 driver, yet I keep getting a error message – USB going OFF – LINE.

This always happens when I leave the machine idling for a awhile and come back to take printouts.
Here are some details of my computer.
TYPE&MODEL – 8434-P1A (IBM)
Operating system – WinXP
Please help me regarding the above
Thanks
Eshan