| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic document feeder capable of reducing a processing time required to determine a rear end of a document and a hole on a document to reduce a conveyance interval between documents, an image reading device, and an image forming apparatus.SOLUTION: In an automatic document feeder, a rear end detection sensor 301 upstream in a document conveyance direction has a detection range set wider than detection ranges of any of document detection means of an abutment sensor 11, a document width sensor 13, a reading inlet sensor 15, and a resist sensor 17. In a direction orthogonal to the document conveyance direction, the rear end detection sensor 301 and the plurality of document detection means are arranged with each other such that all the detection ranges of the plurality of document detection means are included in the detection range of the rear end detection sensor 301. When a controller determines, on the basis of a detection result of the rear end detection sensor 301, that a hole is not present on a document, the controller does not determine the presence of a hole on the document and determines only the passage of the rear end of the document on the basis of detection results of the document detection means. |
