http://www.morfon.com/white-inkjet-cartridge/

Does the ink jet printer cartridge runs out over time if not even ever used?
In other words, I have a printer HP inkjet cartridges with two of them. One is black and the other is color. I only print in black and white (grayscale) because I know that if you print in color, the color cartridge will run out soon. Well, I've written something in the color of a couple of months ago in an accident, and Printer Software companion measure ink levels (among other things) said that the color cartridge was 90% capacity. I have not used since then, but now says it's about 70% of its capacity. I have read that these programs are a bit vague when measuring levels of ink, but the ink in printer cartridges dry up or something if not always used?
When you turn the printer uses some ink to erase the ink-jets to prepare for printing. Therefore, even if you do not use the streams of color, every time you use the printer with a small amount of ink color will be used.
Replacement Phaser 108R00605 Cyan Ink Sticks