Patent ID: 7984906
Filing Date: 2011-07-26
Classification: B65H

Abstract:
1. A medium detection method, comprising steps of: conveying a medium along a transportation path; detecting, based on information obtained at a first position on the transportation path, a first length in a transportation direction of the medium passing the first position; detecting, based on information obtained at a second position that is separated a specific distance from the first position on the transportation path, a second length in the transportation direction of the medium passing the second position; detecting, based on information obtained at a third position on the transportation path, a thickness of the medium passing the third position, including detecting any substantial change in thickness of the medium as it is passes the third position; calculating a third length in the transportation direction of the medium of the substantial change in thickness when it is detected; calculating a corrected difference based on the first, second and third lengths when the substantial change in thickness is detected; and determining if the medium is being conveyed skewed to the transportation direction based on the corrected difference when the substantial change in thickness is detected.