After an inventor has come up with something which might be patentable, often the first step is to conduct a patent search. This can be done by the inventor, the patent attorney or agent, a professional searcher, or any combination of the above. Often at least two searches are conducted, usually one by the inventor, and one by the patent attorney or agent, and sometimes all three types of searches are conducted.
The purpose of the patent search is to see whether the invention meets one of the major criteria of the United States Patent and Trademark Office (USPTO) - namely whether the invention, or improvement to an existing invention, is new and unobvious. Therefore, the searcher will look for previously filed patents or patent applications which describe the same or similar inventions to the one developed by the inventor.
The searchers typically look for related patents in the USPTO and/or the European Patent Office (EPO), although other patent search databases are available. Both the USPTO and the EPO have web sites of both patents and published patent applications which are available to the public. The USPTO has full text searchable US patent records going back to 1976, and images of all patents granted by the US since 1790. But records prior to 1976 have to be searched manually. For patent searching at the USPTO go to: http://www.uspto.gov/patft/index.html. As you can see at this url issued patents and published applications must be searched separately.
The European Patent Office has a single data base which includes the abstracts of US issued patents and published applications and the abstracts many foreign patent records going back to 1968. We use the advanced search at this office which can be reached at: http://ep.espacenet.com/advancedSearch?locale=en_ep
As a general rule, we prefer to do an initial screening search at the European Patent Office. Thus, we have a common database for US issued patents and published applications which also includes foreign patents, and while the search is limited to abstracts, we find that searching abstracts typically gives a good screening search. An further advantage for others is that the EPO image files are in .pdf format, whereas the US image files are in .tif format, and many of our clients have difficulties in downloading .tif files. At the EPO site, there is a guide for searching found under "Get assistance" and we recommend it.