Microsoft Words and other programs have a bad habit of making black type out of all 4 colors. Even though the type may look black on your screen, be sure to check your separation preview when viewing your exported PDF and check to be sure.
Printing fine black type out of all 4 process ink colors requires exact registration. If the registration is off even slightly, you will instantly loose the crispness and clarity of your type. See “Figure A” above for an exaggerated representation of this situation.