The maintenance box stores ink that gets flushed
from the system during print head cleaning. When an ink cartridge
is expended or the maintenance box is at the end of its service
life, you need to replace it.
WF-3720/WF-3730 Series do not include a user-replaceable
You may also need to replace a cartridge that is more
than six months old if your printouts do not look their best, even
after cleaning and aligning the print head.
dispose of your used Epson branded ink cartridges and maintenance
boxes responsibly and in accordance with local requirements.
If you would like to return your used ink
cartridges and maintenance boxes to Epson for proper disposal,
please go to epson.com/recycle for more