Hello MikeMGBGT,
Since one printer is working, and the other is not, it appears to be an issue with the printer having problems. The issue could stem from a few things:
- If it's a wireless printer, it may be caused by the Wi-Fi network that is shared by both the iMac and printer.
- The issue may be related to corrupt drivers or a need for newer driver software to be installed.
- Settings on the iMac for this printer in particular.
That being said, here are a couple of troubleshooting steps that may help to resole your issue: Solve printing problems on Mac - Apple Support. Please go through each of the steps offered on that page, in the order which they appear. If the issue remains after following the steps, you may have to reset the printer as a final solution. Steps are offered on that page as well, but here's the link in case you need it: Reset the printing system on your Mac to solve a problem - Apple Support.
*If you're not using macOS Ventura, you can choose the correct version of macOS for your iMac from the dropdown menu.
Kind regards!