compatibility issues with hp laserjet 600 M601

 We have a new check printer, hp laserjet 600 M601 which we've had multiple issues where it doesn't print the checks.  A little background we have a virtual printer which merges and then send to the check printer, which is set up as a outqueue.  The process hasn't changed only the physical printer has.  We can see where the checks merge, they go to the printer and seem to stick in sending status.  On occasion it appears the printer tries to reject anything coming from JDE. Has anyone experienced this type of issue or have any suggestion to fix it?

Thanks!