The U.S. Patent and Trademark Office (USPTO) has the responsibility for approving patents, but also for denying them as well.
The examiner’s role
Your patent application will be assigned to a patent examiner, who will conduct a search and make an initial determination of patentability of the patent claims. What follows next happens for nearly every patent application – some or all of the patent claims are ‘rejected’.
Reasons for an examiner rejecting your claims include that the invention was not new (someone had done it before), or it was obvious, or that it is for the type of thing that cannot be patented.
Fortunately this is only the start of the patenting process. Usually your patent attorney, working with you, will be able to come up with reasons and arguments for why the claims should be approved. A response to the initial rejection including those arguments needs to be submitted within 6 months. The examiner will then consider the response, and allow the application or, often, reject it again. This cycle can continue – rejection, response, etc. – for some time.
Increasing your odds of success
What can be done to increase the changes that your patent will be approved? One of the most important is to have a patentability search, for ‘prior art’, done before a patent application is prepared and filed.
If it is determined by the search that someone else had previously disclosed or patented the exact same idea as yours, then you will not be able to get a patent.
The more common situation is that some similar prior art is found, but your idea has enough differences that it is still worth pursuing a patent. An experienced patent attorney can help with the searching as well as helping you make judgments about your chances for success.