Patent ID: 8448517
Filing Date: 2013-05-28
Classification: B65H,G01N,G03G

Abstract:
1. A sheet processing device comprising: an ultrasonic wave generator configured to irradiate ultrasonic waves to a sheet being conveyed, from one side of the sheet; a first detecting array arranged on the other side of the sheet in a noncontact manner with the ultrasonic wave generator, configured to detect sound pressure of the ultrasonic waves passing through the sheet; a judging unit configured to judge a state of the sheet by comparing a predetermined value with the sound pressure; a second detecting array arranged on the other side of the sheet at a different position from that of the first detecting array in a conveyance direction of the sheet, configured to detect sound pressure of the ultrasonic waves passing through the sheet wherein the sheet being conveyed crosses first the second detecting array and then the first detecting array; and a position detecting unit configured to detect a position of the sheet at which the first detecting array detects the sound pressure by measuring a time elapsed after the sound pressure detected by the second detecting array has changed.