You would need to fully remove and manually clean the printhead.
Again this is highly unlikely to help though.
Open up the printer, and look for the "carriage" that goes back and forth (on metal rails) over the paper while printing. This is the printhead.
You'll remove the ink cartridges from the printer, then clean on the bottom of them (focus on the ink port/hole) as well as inside the printer where they mate up using qtips and rubbing alcohol.
If you can, remove the carriage/print head (there will be a small lever at the side/rear of it that lifts up to release) and clean the bottom this way as well.
When cleaning the port on the print head that the ink flows into from the cartridge, also try using a qtip to "pump" the liquid down into the port and force it through, which will help to dissolve any clogs. If possible, you'll get better results by using a syringe and appropriately sized rubber tubing (that will fit into the ink inlet port) to force the alcohol to flush through the head)
After all of this swab again with a few dry qtips or give a blast of compressed air to dry everything well, then put it all back together.
Then reset the machine:
unplug power at the wall outlet
wait 5 minutes
press and hold the power/on button for 60+ seconds
keep holding while plugging back in, and for another 60 seconds after, then release
You can now try to print, or run the automated print head cleaning function in the setup menu. You may have to run a few pages through before everything starts flowing properly again.
If that still doesn't help, then that does confirm a hardware fault and again at that point replacement of the printer is the best option.
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