What is reissue?
Patent law states "On taking up an application for examination or a patent in a reexamination proceeding, the examiner shall make a thorough study thereof and shall make a thorough investigation of the available prior art relating to the subject matter of the claimed invention." This means that prior art could disqualify your application for a patent.patented invention
When you conduct the online patent searches, you'll be able to read the full text of the patents and see diagrams. Don't be discouraged if you do find your invention idea is already patented. You may be able to come up with a variation that's not patented...And double check the patent. Sometimes, what looks like the same invention idea may actually be quite different. Some of the free searches may not involve a complete search of all granted patent archives and patent applications for all time. You may want to consider hiring a registered patent attorney to find this information for you.More on Prior Art
Remember, while patent searching is a big part of prior art , it is not everything. If someone has made your invention before you without patenting that still counts against your patentablity. A complete search for prior art might include for example: searching non-patent literature such as any magazine, newspaper, or trade paper article written about inventions like yours also a complete search would include international patent documents (online) and not just those found at the USPTO. Do not make the mistake of believing that just because no one else is selling your product that it does not already exist. After determining that your idea is patentable and qualifies for a patent - you now need to decide if the expense of patenting is worth it.how to find out if an idea has been patented
how do i do a patent search - Learn about using the USPTO's AppFT product for searching patent applications.The Do-It-Yourself Patent Search
If you decide to do the patent search yourself, you have several search methods available: The USPTO (United States Patent Trade Office) Public Search Facility. The USPTO operates a Patent Public Search Facility located in Alexandria, Virginia. Here every U.S. patent granted since 1790 may be searched and examined. Many inventors like to make at least one pilgrimage to the Patent Public Search Facility. It's located fewer than 15 minutes from National Airport by taxi; Metro Rail serves it off the Blue and Yellow lines, King Street Station; and several hotels are within walking distance, so it's easy to get to and around.