The invention provides a movable cover for a finger receiving surface of an optical platen in a fingerprint imaging device. A heater incorporated into the platen cover applies controlled heat to the finger receiving surface when the cover is closed over the platen. Maintaining the finger receiving...http://www.google.de/patents/US5825474?utm_source=gb-gplus-sharePatent US5825474 - Heated optical platen cover for a fingerprint imaging system
