Some workstations do not have any network printers listed in their inventory even though there are printers installed and working on the machine.
For ZAM 7.5 - Fixed in ZENworks Asset Management 7.5 Interim Release 22 or newer
Interim Releases can be scheduled to run automatically or can be downloaded manually at https://download.novell.com/patch/finder. The Interim releases can be set up within the ZAM Manager for the Task server to check the site on a scheduled basis, and download and apply them automatically. Please refer to the Help Section details of how to set up automatic downloads if desired.