I found a fairly recent book (released last April) discussing the role of black inventors, called The Inventive Spirit of African Americans: Patented Ingenuity, by Patricia Carter Sluby, an ex patent examiner.
Here is an article about the book. In part, the article states:
Ms. Sluby's book grew out of her job as an examiner at the U.S. Patent and Trademark Office. After being asked by an administrator there to put together a list of African American inventors, she began searching back through history for names. She was surprised by what she found.
"The African American inventor has invented in every subject any other person has invented in," Ms. Sluby says. "From agriculture to games to computers, they have turned around industries, bringing us a better level of living."