In some print cycles a very small amount of surplus ink may be collected in the maintenance box. To prevent ink leakage from the maintenance box, the printer is designed to stop printing when the absorbing capacity of the maintenance box has reached its limit. Whether and how often this is required will vary according to the number of pages you print, the type of material that you print and the number of cleaning cycles that the printer performs.
When a message is displayed prompting you to replace the maintenance box, refer to the animations displayed on the control panel. The need for replacement of the box does not mean that your printer has ceased to operate in accordance with its specifications. The Epson warranty does not cover the cost of this replacement. It is a user-serviceable part.
When it is full, you cannot print and clean the print head until the maintenance box is replaced to avoid ink leakage.