What does a patent examiner actually do? In the UK Patent Office, the main duty is to ensure that patent applications meet the requirements of the patents section of the 1977 Copyright, Designs, and Patents Act. If the application does, a patent can be granted to the applicant(s).
So what does this mean on a daily basis? A person, usually using a patent agent (a highly recommended, although not strictly necessary choice) decides they want to have a patent for their invention, so they send in an application. There are certain requirements to be fulfilled, mainly that there's at least a minimum of a request for the grant of a patent and a description (which includes any drawings) of what's been invented. Eventually, the application must have a set of claims, an abstract too. Patent claims are what define the monopoly that will be given protection by the patent. These define the invention itself, and are NOT about how much it will be sold for, or that it's a really good kind of teapot. Ack.
Every examiner will have a field that they work in, usually with a few other colleagues doing the same kind. There is a large and detailed patent classification key, with people in charge of small sub-divisions of it. Sticking to a small number (or indeed just one) field of technology allows the examiner to build up a degree of expertise that is invaluable.
Once the claims have been submitted, then the first part of an examiner's job can begin - which is the search stage. There are several methods used for this, and the most common one is the use of specialised databases (in the UK, these are actually linked to the European Patent Office's computer systems). Also used, but with less frequency are an extensive collection of documents in physical filing systems. These are used for areas of technology that for one reason or another don't lend themselves to key-word searching. The invention, as defined by the claims, is searched using these techniques, and any previously existing prior art that comes close or matches the claimed monopoly is sent to the applicant, alongside a report on what was searched. After this process, the application is published, and now any member of the public can see it.
The second part of an examiner's job is the actual process of substantive examination. This get down to the basics of whether the patent is allowable or not. There are certain criteria to be fulfilled before grant, and it is rare for an application to meet them at the first examination, although it does sometimes occur. Because of this, amendments to the application are made by the applicant or the applicant's agent are made until either the application is dropped or granted.
The main criteria for a granted patent are that it must be:
Others are that it must only relate to one inventive concept, not a whole bunch of them, and it must be clearly described.
So, based upon the results of the search, the examiner will carry out a series of tests on the application to ensure it matches these criteria. If it doesn't, then a report is written to detail the objections, to which the applicant is given time to respond or submit amendments to over come them. If it's all in order, it is granted after a small delay.
Search and examination are the two basic jobs of the patent examiner. Others include maintaining the classification keys, classifying inventions, attending hearings on cases where no agreement between the applicant and agent is possible and other functions, such as training.
The life of a patent examiner is always intense.
See:
http://www.patent.gov.uk/
http://www.intellectual-property.gov.uk/
for more information about the UK patent system