Printing Sessions not closing

I'm running Windows 2000 Professional.
I'm hosting 2 ip printers. My problem is that when a user prints to one of the printers everything works as it should:::But the connection to my computer is not removed.

In Computer Mangement Console under shared folders the sessions folder shows all connected users. Some disconnect after they print and some stay forever (or until I reboot or disconnect them). When the load reaches 10-12 users only the connected users can print. No new connections to my computer can be made.

Is there any way to auto close these sessions??? Or any other workaround????Disconnect any users that are idle.

Thanks