A curl control system applicable to an electrophotographic copier for sensing the conditions of curls of a paper being transported and correcting the curls includes a curl sensing device and a curl correcting device. Two distance sensor units illuminate the paper and receive a reflection from the paper...http://www.google.fr/patents/US4926358?utm_source=gb-gplus-shareBrevet US4926358 - System for controlling curls of a paper
