Items won't print...sometimes print after restart or wake from sleep?

Hi all - I have a Phaser 6600DN on Windows 10. I have the printer connected by ethernet to my network. I installed the printer through the Windows Control Panel using 'Add a Printer' and it found it and installed drivers automatically, no problem. The printer seems to have automatically picked up an IP address through DHCP correctly as I can see it listed in the router and Windows is showing no errors other than 'no toner' as the Cyan cartridge is empty, so it will not print normally....fine, when I print I set the document to 'Black and White' so all should be fine there.

The issue is, printed documents never seem to reach the printer. Items sent to print will SOMETIMES print if I put the printer to sleep and wake it back up (they print once it wakes up), or sometimes print if I turn the printer off and then back on again.

It's been, probably, 6 months since I've last used it, but this was not an issue when I used it before.

What could the issue be? Thanks for any suggestions and help!