SHEET FEEDING DEVICE, CONTROL METHOD THEREOF, IMAGE READING DEVICE AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To detect an abnormal conveyance state of a type that a sheet bundle does not jump up even if a user forgets to return a multifeed detection means from a non-detection state to a detection state when a sheet abnormality detection means and the multifeed detection means are adopted as a means for detecting the abnormal conveyance state of the sheet bundle.SOLUTION: A document feeding device 101 feeds sheets one by one from a platen 1 to a conveying passage. A document abnormality detection sensor 35 detects the deformation of the sheet fed by the document feeding device 101. A multifeed detection sensor 32 is arranged at the downstream side of the document abnormality detection sensor 35 in the conveying direction, and detects a plurality of sheets which are fed in an overlapping state. An operation part 46 sets the document abnormality detection sensor 35 to be activated or deactivated. A control part 45 sets the multifeed detection sensor 32 to be also activated when the document abnormality detection sensor 35 is set to be activated.