Epson's built-in cleaning cycles solve the vast majority of streaking and missing-color issues, but running them too aggressively can waste ink without fixing anything.
Symptoms to look for
Streaks, gaps, or faded sections in printed output
One specific color missing from prints
Print quality declined after a period of not printing
What causes it
Dried ink in the fine nozzle openings, most often from infrequent use, is by far the leading cause of these symptoms on inkjet and EcoTank models alike.
How to fix it
Run a nozzle check pattern from the printer utility to identify which colors are clogged.
Run one head cleaning cycle, then reprint the nozzle check.
Repeat up to 3 cycles maximum, waiting a few minutes between each.
If nozzles remain clogged after 3 cycles, run a 'power cleaning' cycle if your model supports it.
Persistent clogging after power cleaning may indicate a cartridge or print head replacement is needed.
Technician's tip
Printing something small at least once a week, even a test page, is the single best way to prevent nozzle clogs from forming in the first place.