A three-dimensional printer uses inkjet-type printheads to rapidly prototype, or print, a three-dimensional model. A powder feeder includes a conveyor system and a metering system to deliver powder to a build area in measured quantities. The powder feeder also includes a vacuum system for loading powder...http://www.google.com.au/patents/US20100151136?utm_source=gb-gplus-sharePatent US20100151136 - Three-Dimensional Printer
