Yeah, that's the funny thing. I used to work at a print shop and book publisher, so I've got some background on this. Here's how you usually handle black in four-color printing:

- If you have plain black text and line art, you simply use black ink for that part.

- If you have four-color-process graphics, it includes all four colors including black.

- If you have an area of solid black where you want it to be super saturated and dark, you mix in some of the C,M,Y colors into it, so that you get an even darker black than just black ink will provide. You'll even do tricks with chokes and spreads to make sure that a slight misregistration in the printing plates doesn't cause rainbows to bleed out of the black area. And even when you do mix some CMY into the K, you never do it at 100 percent saturation because that's going to oversoak your paper and plates and cause hickeys on your final output.

- You would not normally do plain black text by using all-four-CMYK-colors, because on the fine lines of text, you can't get the necessary control over chokes and spreads to hide registration problems. Plus, that would waste ink.

All of the above is, in professional printing, carefully controlled by the separations software with a billion little settings and various tricky stuff you can do. But on a consumer inkjet printer, it's done automatically by the printer driver and whatever app you're printing from.

What I believe to be happening here is that Adobe Reader is doing the Bad Thing of using all four inks, even for plain black. Possibly, it's doing it for the same reason I originally stated, that it's rasterizing the whole thing down to a single graphic and printing that, so the printer treats it like it was a single large CMYK graphic and thus uses all four inks. The other pieces of software are doing the right thing and sending the fonts and graphics to the printer separately.

Anyway, in the end, you don't have a software problem here, you've got a clogged or empty black ink cartridge. Have fun. :-)