High Volume Network Printer Problem

Hi,

Basically we have a high volume Xerox 2060 colour printer which is in constant use by two types of users.
1) NT4 workstation clients printing from various applications via a printer setup on a standard TCP/IP port. The job is then re-spooled by the 2060's Fiery Spool server.
2) Win2K Telnet clients printing via a Sun O/S server, which is passing the jobs directly to the 2060's Fiery Spool server.
The problem is this.. if both sets of clients print at the same time the spool server locks up and has to be restarted, at the moment people are taking it in turns without a problem but it does need to be sorted out.
Any ideas?