An image scanning apparatus can obtain, using a simple optical detection system, original sheet information including size and displacement information of an original sheet before an image scanning operation starts. The image scanning apparatus comprises a single beam emitting unit for emitting a coherent...http://www.google.es/patents/US5479274?utm_source=gb-gplus-sharePatente US5479274 - Optical image scanning apparatus detecting sheet size and displacement
Optical image scanning apparatus detecting sheet size and displacement
