This doesn't quite add up, and it contains few strong sources. What it says is that O'Reilly invented the rotary tattoo machine, however the same article states that rotaries weren't produced for another 100 years. O'Reilly's article says tattoo machines haven't changed much since then, but the other article says that tattoo machines virtually immediately changed to the 'doorbell' type (usually thought of as the older technology). Even now, rotaries aren't the dominant technology although they have exploded in popularity recently. What I'm taking from this is that a rotary machine was patented by O'Reilly, but it didn't really take off at all during his lifetime. Certainly you would make little money manufacturing them to sell, as tattooing was nowhere near as commercially viable then, and it was a simple matter to make your own machines from doorbell circuits anyway. There's a lot about tattoo history that's largely myth or hearsay, and I think Wiki can be the victim of 'false consensus' a lot of the time. I'm not saying the articles are necessarily wrong, but they seem as though they've been edited by a bunch of people who have agreed on the truth rather than referenced it. Although you can't fault the idea that the electric pen was a 'predecessor' to tattoo machines, it doesn't necessarily follow that they are related. In fact, the only relevant link that worked that I could find in that article, gives no proof other than "1891 : New Yorker Samuel O’Reilly patents the first electric tattoo machine, a modification of Thomas Edison’s perforating pen.". So I think there's a lot that's open to interpretation, and I would personally love to know some real facts on the subject.