A patent search is performed so that all applicable prior art is found. While a search is not required before a patent is filed it is a good idea for a few reasons:

Any prior art that comes to the attention of anyone involved with the prosecution of the application, must be disclosed to the PTO. This disclosure is called an Information Disclosure Statement (IDS). This document can be filed at various times, with various costs. Its purpose is to disclose any information that could be considered “material to patentability”.

Any published patent, publication or similar document can be included in an IDS. An IDS can be filed for free during the first 3 months after the filing of the application. After the 3 months passes the cost is more and/or the proof that the information was newly discovered is more rigid. If the IDS is not filed before the issue fee is paid, the application can not be issued, and a continuation would need to be filed.

Many times a invention can be made that is the same as an existing patent or disclosed in a published document. A search can find such prior art and the inventor can then choose to not file a patent, or can also choose to add some new, novel, non-obvious improvement so that the invention “clears” the prior art. There are patenting agencies like InventHelp that are here to help new inventors patent their inventions – learn more about InventHelp.

A patent examiner will do their own search of existing patents and other document from various sources. The results of this search will be used against an applicant, in the form of a rejection in an Office Action. Finding as much prior art as possible is necessary to see that the examiner has as little to work with as possible.

So it is in the best interests of an inventor to do a good job searching for prior art.

It is possible for an inventor to do their own search. One way is via various search engines on the Internet. However, Internet. Searches may only be able to find prior art up from about the 1980’s on. Any prior art previous to this might be needed and could not be searched on the Internet.

The next best place to search would be one of the Patent and Trademark Depository Libraries (PTDL). These libraries are set up at universities and in major cities and they have excellent search facilities. They also have staff that will help an inventor understand the search tools, but they will not perform a search for you. These libraries have all patents ever issued in bound volumes. They also have automated tools that will search for keywords or concepts and return the patent numbers of matching documents.

It can also be useful for a third party to perform a search at the PTO’s office. This search will simulate the searches that the examiners would use. They will be performed at the PTO’s search facility and examiners may be consulted by searchers.

But a searcher can only search to the extent they understand your invention. So the best search of all would be performed by an applicant traveling to the PTO, in Washington, DC and performing the search and talking with examiners in person. The third party search can cost about $400 – $600, depending on the firm and the subject matter. A third party search can take 3 to 6 weeks to be returned, although the actual search will take not more than 8 hours as explained on https://azbigmedia.com/business/why-new-inventors-turn-to-inventhelp-for-support/.