Photoshop save to Black (K=100) Only

How do I adjust a greyscale image in Photoshop to only use Black (K=100)?

The issue I am faced with is that greyscale seems to use different shades of black.

Thanks,
Kim

Do these threads help?

http://graphicdesign.stackexchange.com/questions/3752/how-do-i-change-a-single-layer-to-grayscale-in-photoshop-cs4

http://forums.adobe.com/message/3198649

http://forums.adobe.com/thread/1105677

http://forums.adobe.com/thread/802752

http://www.photoshopessentials.com/photo-editing/black-and-white/black-and-white-intro/