A patent examiner (or, historically, a patent clerk) is an employee, usually a civil servant with a scientific or engineering background, working at a patent office. Major employers of patent examiners are the European Patent Office (EPO), the United States Patent and Trademark Office (USPTO), the Japan Patent Office (JPO), and other patent offices around the world. Duties Patent examiners review patent applications to determine whether the invention(s) claimed in each of them should be granted a patent or whether the application should instead be refused. One of the most important tasks of a patent examiner is to review the disclosure in the application and to compare it to the prior art. This involves reading and understanding a patent application, searching the prior art (including prior patent applications and patents, scientific literature databases, etc.) to determine what contribution the invention makes over the prior art, and issuing office actions to explain to the applicants and their representatives (i.e., patent attorneys or agents) any objections that may exist against the grant of a patent. In other words, an examiner reviews a patent application substantively to determine whether it complies with the legal requirements for granting of a patent. A claimed invention must meet patentability requirements of novelty, inventive step or non-obviousness, industrial application (or utility) and sufficiency of disclosure. Examiners are expected to be efficient in their work and to determine patentability within a limited amount of time. Some patent applications are easy for an examiner to assess, but others require considerably more time. This has given rise to controversy: On April 13, 2007, a "Coalition of Patent Examiner Representatives" expressed concern that Offices European Patent Office Patent examiners at the European Patent Office (EPO) carry out examination and opposition procedures for patent applications originating anywhere in the world and seeking protection in any of the member states of the European Patent Organisation. The process involves a search for existing documentation in the technical area of the application (prior art) and communication with the applicant in order to bring the application in line with the legal requirements of the European Patent Convention. For every patent application, a division formed by three examiners must decide whether the application is granted or not, and in which scope. EPO examiners are organized in a branched structured by their technical field of expertise and examine patent applications in three official languages, English, French, and German.