Vervolg:
For those that don't know, this isn't the first time that an edrum maker/manufacturer was forced to stop selling in the states because of the threat of legal action on the part of Roland. Chances are Roland is most likely citing patent number US 7,385,135 B2 (or some variant of it) as the patent that is being infringed. Roland doesn't have a patent on mesh heads. Their patent (that I listed above) is for an entire system. All one has to do to infringe on that patent is to have two or more of the listed parts of the system in their design. The patent is very specific on general aspects of a mesh head based edrum system (Yes, that sounds odd, but read the patent for yourself). So, if you use a mesh head and foam touching the drum head to make connection with the sensor, you just infringed on Roland's patent.
Zo simpel is het dus, Roland kan waarschijnlijk in de US alle concurrentie tegenhouden doordat ze het concept hebben gepatenteerd. Beetje ranzig, naar mijn bescheiden mening. Aan de andere kant ligt zoiets in Europa een stuk lastiger.