Without pictures or some sort of description, it's hard to respond in anything but the most general of ways. Here's my thoughts on the subject:
It's hard to come up with something that is totally new in pen making. New to you doesn't necessarily mean new to the world. I'm not saying your idea isn't new and revolutionary (I have no idea based on your post). It's just my experience that re-invention is a lot more common than invention.
Generally, someone who invents something truly new, who doesn't want it copied, will get a patent. This doesn't prevent copying, but you can at least take steps to limit production / sale in your home country. New ideas that are not patented are quickly adopted and used by artisans and commercial outfits. If you read about the history of pen making, particularly in the glory days of the early 20th century, it's filled with tales of idea poaching and epic legal battles.
If you read back through this forum, you might be able to figure out who posted the first cigar illusion, steam punk, feather, poly clay, on and on and on pens. Plenty of people making them now. And maybe the first poster here was the originator or maybe they just took an idea and ran with it. Does it really matter? If money is at stake then the answer is generally yes, otherwise not so much. Plenty of ideas offered up here just to advance the art of pen making.
Some people won't post pictures here because they don't want their ideas copied. Not posting pictures here might slow things down, but then you also can't sell online either. If you don't want people copying your designs, then develop skills / processes that the average person won't be able to duplicate. If you invent something that is easy to do, then expect it to be copied. Even if you patent it.
Pens, smart phones, virtual assistants, music, art.....anything. If it's a good idea and it's easy for anybody to do, it will spread like wildfire. Especially if you can make a buck doing it.
Ed