Auto-document feeder and document feeding method

Abstract

An auto-document feeder includes: a document placing section on which an original document is placed; a sheet detection sensor configured to detect the original document, length in a feeding direction of the original document being first length larger than second length; a length detection sensor configured to detect the length of the original document while the original document is fed; a first feeding path for feeding the original document to a reading section for reading an image of the original document; a second feeding path for feeding the original document to the reading section, the second feeding path being different from the first feeding path; a switching section configured to selectively switch the first feeding path and the second feeding path; and a control section configured to divert, with the switching section, the original document to the first feeding path if the sheet detection sensor detects the original document.

1 . An auto-document feeder comprising:
 a document placing section on which an original document is placed;   a sheet detection sensor configured to detect the original document placed on the document placing section, a length in a feeding direction of the original document being a first length larger thap a second length;   a length detection sensor configured to detect the length in the feeding direction of the original document while the original document is fed;   a first feeding path for feeding the original document placed on the document placing section to a reading section for reading an image of the original document, a distance from the length detection sensor to the reading section in the first feeding path being larger than the first length;   a second feeding path for feeding a different sheet of the original document placed on the document placing section to the reading section, the second feeding path being different from the first feeding path;   a switching section configured to selectively switch between the first feeding path and the second feeding path; and   a control section configured to divert, with the switching section, the original document to the first feeding path if the sheet detection sensor detects the original document.   
     
     
         2 . The auto-document feeder according to  claim 1 , wherein the first length is a maximum length in the feeding direction of the original document that the auto-document feeder can feed. 
     
     
         3 . The auto-document feeder according to  claim 1 , wherein, in the second feeding path, a distance from the length detection sensor to the reading section is smaller than the first length. 
     
     
         4 . The auto-document feeder according to any one of  claim 1 , wherein, if the sheet detection sensor does not detect an original document having the second length smaller than the first length placed on the document placing section, the control section alternately diverts, with the switching section, the original document to the first feeding path and the second feeding path. 
     
     
         5 . The auto-document feeder according to  claim 1 , wherein, if plural documents are placed on the document placing section, the control section receives input of a mixed document mode indicating that an original document, a length in the feeding direction of which is the first length or the second length smaller than the first length, is included and, if the input of the mixed document mode is received, diverts the original documents to the first feeding path or the second feeding path on the basis of a detection result by the sheet detection sensor. 
     
     
         6 . The auto-document feeder according to  claim 5 , wherein, if the sheet detection sensor does not detect the original document having the second length placed on the document placing section, the control section alternatively diverts, with the switching section, the original document having the second length to the first feeding path or the second feeding path. 
     
     
         7 . A document feeding method for an auto-document feeder including: a sheet detection sensor provided in a document placing section; plural feeding paths for feeding an original document placed on the document placing section to an image reading section, lengths of the plural feeding paths at least from a length detection sensor to the reading section being different from one another; and a switching section configured to selectively switch the plural feeding paths, the method comprising:
 determining whether an original document, the original document having a length in a feeding direction of which is first length larger than second length, is detected by the sheet detection sensor; and   diverting, if the original document placed on the document placing section is detected by the sheet detection sensor, with the switching section, the original document to a first feeding path, a length of which is larger than the first length of the original document, among the plural feeding paths.   
     
     
         8 . The method according to  claim 7 , wherein the first length is a maximum length in the feeding direction of the original document that the auto-document feeder can feed. 
     
     
         9 . The method according to  claim 7 , further comprising receiving, in reading plural original documents, input of a mixed document mode indicating that an original document, length in the feeding direction of which is the first length or the second length smaller than the first length, is included and, if the input of the mixed document mode is received, diverting, with the switching section, at least the original document having the first length to the first feeding path on the basis of a detection result by the sheet detection sensor. 
     
     
         10 . The method according to  claim 8 , wherein
 the auto-document feeder includes a second feeding path, and   the method further comprises alternately diverting, with the switching section, the original document to the first feeding path and the second feeding path if the sheet detection sensor does not detect an original document having the second length.