Black print head clogged, not printing.
My blck ink is not out, the panel shows that it's about 2/3 full. But it won't print anything black, printer is HP 6500 Office jet E709a
First check the HP 920 ink cartridge vents are properly cleared
Then run up to three cleaning cycles from the toolbox or printer front panel.
If the above does not resolve the issue the initialization following a hard reset may.
Perform a hard reset as follows: turn on the printer and wait for any printer motions to stop. With the printer turned on and idle unplug the power cord for thirty seconds, then plug the cord back in. Turn the printer on and allow it to go through any required initialization. There will likely be a warning message
afterwards suggesting keeping the printer plugged into a live outlet. This is good advise in general, but can be ignored for this case