To add to the basic diagnostic suggestions made by Canadian_Dave:
'Print' a sample document, but select the 'print to file' option in the driver preferences.
'Send' the contents of the resultant file (e.g. testfile.PRN) to the printer port (to confirm that the fault still occurs), by issuing (from a Windows command-prompt session):
lpr -S ip_address -P any testfile.PRN
where ip_address is the TCP/IP address of the target printer port.
You can then also send the contents of the file to another similar printer, for comparison, to eliminate (or not) the possibility of a random driver error.