Did Xerox ever sue people/businesses for using the Xerox trademark to generically refer to any old photocopier?
The reason Xerox lost control of the Xerox brand-name as a trade-mark was specifically because they did *not* enforce use of the Xerox name to mean their photocopies only and not photocopies in general. That’s one of the things about trade-marks… if you don’t defend them, then the default position of the courts is that it didn’t matter to you, which means you missed your chance to hang onto the trade-mark, and so you have to let it go. The same thing happened with the term “escalator”, which used to be a specific brand-name, but now is a generic term because the escalator company didn’t enforce application of the term escalator to their product only.