Other than prior art, what can prevent a patent from being obtained?

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18. Other than prior art, what can prevent a patent from being obtained?

Several occurrences can prevent a patent from being obtained. In the U.S., if an invention is exposed, such as at a trade show, in a magazine or other printed publication, sold, offered for sale, used in public, or the like, then the inventor only has one year from the time of exposure to submit a patent application. If an application is not filed within the one year grace period, and depending upon the exact circumstances of the exposure, it may not be possible to obtain a patent on the invention. For example, if a sample of the invention is sold at a trade show, the inventor must submit an application within one year or a patent can never be obtained. Another requirement for obtaining a patent is that the inventor must make a complete disclosure of the invention. That is, the inventor cannot withhold or otherwise keep secret any pertinent information regarding the invention. If this is not done, either the patent will not be allowed, or worse, after issue may be found invalid.