If you make an item and someone else patents it later, Can you still make and sell your item .

Question

I made something in 2010 and sold some via a website. I did not patent it due to prohibitive patent cost. 
 
Someone else patented a similar item 6 yrs later.  When they received that patent the patent examiner cited my item and website in the approved patent. 
 
Can I still make and sell my item without fear of legal issues.

Peter D. Mlynek · Answer

This is a common question, that has been litigated a number of times.  The good news for you is that the courts usually rule against the patent owner, and in favor of people in your position. 
 
This has to do with fairness.  If you are making and selling your invention, you cannot all of the sudden start infringing a patent that was filed after you’ve been selling it.   
 
It also has to do with logic.  Either your product lies within the scope of the claims or it does not.  If it does not, then you are not infringing, and you win.  If it does, then at least some of the claims of the patent are invalid, and you win.   
 
There are instances when one person invented something, kept his invention a secret, and later a second person independently invented the same thing, got a patent, sued the first person and won.  But this is not the case in your situation -- we know that you did not keep your invention a secret because the Examiner cited it. 
 
Can the patent owner cause a problem for you?  Well, yes, if you are a small operation and they have lots of money, even if you win, it will still be expensive for you.  And there may be some bizarre situation that the court would find against you. 
 
Make sure not to tweek your design that would actually bring you within the scope of the claims of the patent.   
 
Good luck!

Q: If you make an item and someone else patents it later, Can you still make and sell your item .