Epson NX400 prints color even when "black & white" is chosen.

[Wesito]

I have a MAC OS X 10.5.8 and an Epson NX400 printer. To print without color, in "Printer Features"
I choose "Color Model:" and then "black&white". Until recently this worked fine. Now only color is
printed. Have long been using Cartridge World cartridges, which work well and seem to have no effect
one way or the other on this problem.

I print a great deal in b&w and don't want to waste color in the black. Is there a repair or adjustment
I can make?

Wesito

[Geek-9pm]

Welcome!
Computer Hope is the number one location for free computer help.
The forum will help everyone with all computer questions.

You need to clarify some things.
A. You are not using new Epson cats and the problem only showed up after you put in some other band. Right?
B. You have not had nay other issues with the printer.
C. You print a black and white document and color fringes show around the letters and so you reason that that it is using color ink to create a black area. Right?

Consider the following...

.. behavior of the Epson ... is not a flaw in the printer software. It is a special feature. When black ink level is low, color ink is used to continue print ...

Does this apply to your printer? Check the documentation.You should find how to disable this thing.
--OR--
Do do you mean that you want to print color photos in black and white? Are you sure you are making then right selections for that? If you really want a photo in monochrome, it should be done in your photo program. Convert the image to monochrome,  print it, then undo the conversion and/or do not  save the change.
Does that help any?
-------------
EDIT: The quotation is a paraphrase, It is documented by Epson. Reference on request.

[Salmon Trout]

Epson Stylus NX400 All-in-One Printer

Q: The color ink cartridge is expended even though I print in black only. Why does this happen?

A: To keep the print head clear, the printer uses a small amount of ink from all the cartridges whenever it prints and to keep the print head primed. Even if you select Black Only, some color ink is still being used.

[Salmon Trout]

The above, I think it is safe to say, is true of all inkjets, in fact they use ink even when you don't print anything at all. They periodically perform a head clean cycle using - what else? - ink.

[Wesito]

Thanks for your input. What I may not have explained all that clearly is that on the To Print page
there is a choice. One can mark "color" or "black&white". I realized that it no longer mattered if
I chose "black&white", any color item would print in color. (First noticed in a banner whose color
didn't matter to me, looked just as good in b&w.
      You wrote:
You need to clarify some things.
A. You are not using new Epson cats and the problem only showed up after you put in some other band. Right? Wrong. Am using non-Epson
cartridges, have been for a long time. There's no correlation with the b&w-color problem
B. You have not had nay other issues with the printer.
Right, I haven't
C. You print a black and white document and color fringes show around the letters and so you reason that that it is using color ink to create a black area. Right?
        No. Per above, I realized it when I printed a color banner. Tested on several other pages. Anything in color printed in color, no matter which I chose on the To Print page. 
       And no, I don't want to print color photos in black and white, as a rule.
    I'm not surprised that, as you say, "When black ink level is low, color ink is used to continue print ..."  Epson, cartridge-wise, couldn't be sleazier. Vampires.

Anyway, thanks for your input.

Wesito