A method for determining a present air density for an imaging mechanism is presented. During a first time period: in a determining and storing action, a nominal air density is stored. In an increasing action, a fan input is increased until a known pressure in a cavity coupled to a fan receiving the fan...http://www.google.es/patents/US6621990?utm_source=gb-gplus-sharePatente US6621990 - Method for determining air density
