When the 
notification icon appears above
an ink color on the LCD screen, the ink color is low or expended.
If one of the installed ink cartridges or ink supply units (ink
packs) is expended, printing cannot be performed until the expended
ink is replaced. If an ink cartridge or ink pack is expended while
printing, the print job will stop and you can continue printing
after replacing the ink.
If you proceed to print with an ink cartridge or ink pack that is running low, you may be required to replace the ink while the print job is still in progress. If you have to install a new ink cartridge or ink pack during a print job, colors in your printout may look different depending on how the ink dries. To avoid this, Epson recommends that you replace any low ink cartridges or ink packs with new ones before printing large jobs. The removed ink can be reinstalled later and used until the remaining ink is expended.
The maintenance box stores ink that gets flushed from the system
during print head cleaning. If a message appears or the notification icon appears above
a maintenance box icon on the LCD screen, the amount of available
space in the maintenance box is low. When a maintenance box is
full, you need to replace it.