The epson L210 (and all the L series) calculating the ink level, by counting the printed pages. The printer has programmed to recognize a full tank as about 4000 pages. When the count goes upper than 3500 or 3600 pages (I am not sure for the exactly number because I am a user too, no an technician), the printer start to warning you that the ink level is low by blinking continually the ink (orange light)…. When the count reach the 4000 pages the ink light go on permanently and the printer stop to work and it doesn’t print anymore.
All the above is the protecting system of the printer and that is not mean that the machine is broke.
The printer can not recognize if someone put more ink in the tank. For this reason if someone refill the tank before the printer ask it (by blinking permanently the ink light), the machine continues to “think” that the ink level is low so it start the warnings.
Anyway if someone has refill the tank, before the printer ask it, and suddenly after few printed pages the print stop work and the ink light is on permanently, then just unhook the tanks of the printer just like as you will do when you want to refill the ink tanks. There is somewhere in the hooks a switch that help the printer to understand when the tanks is on the machine or not.
So if the ink light is permanently on and you unhook the tanks, the printer thinks that you filling up the ink tank and it removes the warning of the light and the printer start work again.
IT WORKS ONLY IF THE INK LIGHT IS PERMANENTLY ON and no when it blinking. Because the printer needs to make a reset on his page counting and that can be happen right only if the light is on.