The high-capacity ink tank system is the reason the Epson L3256 can store more ink.
Each tank is designed for a different color.
There is a text label above the transparent window of each tank.

This ink pad is added into the printer to fulfill one purpose only.
Just like every other component in the printer, it has its own lifetime.
Unfortunately, Epson doesnt provide enough information about the ink pad.

Also worth mentioning is that the ink pad replacement isnt free even though the printer is still in warranty.
Meet Epson L3256 Resetter.
It offers the simplest approach to the problem that doesnt even require you to replace the ink pad.

This is what Epson L3256 Resetter is capable of.