Printers Disappearing From Chooser

We have several MAC g4s running OS 9.2.2. We have 2 hp lj 5000n a laserjet 5si and a techtronics phaser 480. The G4s have Asante 10/100 nics going through a Dell PowerConnect 3048 (with most recent firmware). All printers have a local ip statically assigned.

These printers are disappearing then reappearing then disappearing on a constant basis. It happens more on some macs than others.

Any idea on why this happens and how to fix it.