Have Epson DX8400. Have tried to to replace the black ink cartridge with Epsons own ink:0711, but printer will not accept. Have tried with a different make but still no joy. Had printer for 2 1/2 years and never had problems before. Can you help? What comes up on the little screen is: "Cannot recognize cartridges". Across the top is the little red band with" x Error"

That is normal behaviour in Epsons. You will have to replace empty cartridges.
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Dear friend,

There may be a problem with the newly purchased black cartridge.Try with another one,if it works then reurn the faulty to the purchased shop for replacement.If all won't help check with the auhorized service centre for problems.

I have an epson dx8400 printer and changed all the cartridges but it still does not recognise the black ink. Any suggestions

use original ink cartridges supply by epson

Epson,. has it rigged, that you must have ink in all the cartridges.............! Doesnt make a difference, if you are printing black and white ONLY.

You have to replace them.

Good Luck......

I Have this problem too with the pink ink, ive replaced it and now it will not detect that there is even an ink cartridge in the printer at all...

on the ink cartridges there should be a little gold chip on them if they dont have that then your printer will not recognise the ink my best bet for you is to buy cheep and reliable placement epson ink or you can buy these ink cartriges which have tubes which feed ink into these replacement cartridges and i have got one of these my self and i would recomend these to anyone

Sorry Desperate. All inkjet printers, from all companies,  are programed to only operate with ink in all containers to avoid other problems. Their is no workaround. Please rate me not harshly just  because you don't like the answer. Rate based upon the truth of an answer. 

replace cartridge, take the cartridge back to get another, this is a common issue.

It is most likely a faulty chip, return the cartridge to the supplier for a replacement. In my experience as many as 5% of compatible cartriges are faulty