Automatic sheet feeder

Abstract

An automatic sheet input tray, first to third passageways, a temporary tray selectively communicating with the first and second passageways, a sheet-feeding mechanism, and a sheet output tray. The sheet-feeding mechanism feeds a first sheet from the sheet input tray to the sheet output tray successively through the first passageway, the temporary tray, the second passageway, the first passageway, and the third passageway in a duplex mode. When the first sheet is fed to the third passageway, a second sheet is fed to the first passageway in the duplex mode. In a simplex mode, the mechanism feeds the first sheet from the sheet input tray to the sheet output ray successively through the first passageway and the temporary tray, and the first sheet falls from the temporary tray to the sheet output tray.

1 . An automatic sheet feeder, comprising: 
 a sheet input tray for storing a plurality of sheets including a first sheet and a second sheet, each of the first and second sheets having a front side and a back side;    a first passageway, a second passageway, and a third passageway, through which the first and second sheets may be successively fed, the first passageway communicating with the sheet input tray, a first end of the second passageway selectively communicating with the first passageway, a second end of the second passageway communicating with the first passageway, and the third passageway selectively communicating with the first passageway;    a temporary tray selectively communicating with the first passageway and the second passageway;    a sheet-feeding mechanism having a duplex sheet-feeding mode and a simplex sheet-feeding mode;    a sheet output tray, in which the first and second sheets after being fed are stored, communicating with the third passageway, wherein:    in the duplex sheet-feeding mode, the sheet-feeding mechanism feeds the first sheet from the sheet input tray to the sheet output tray successively through the first passageway, the temporary tray, the second passageway, the first passageway, and the third passageway, and when the first sheet is fed to the third passageway, the second sheet is fed to the first passageway; and    in the simplex sheet-feeding mode, the sheet-feeding mechanism feeds the first sheet from the sheet input tray to the sheet output tray successively through the first passageway and the temporary tray, and the first sheet falls from the temporary tray to the sheet output tray.    
   
   
       2 . The automatic sheet feeder according to  claim 1 , wherein the first passageway comprises: 
 a main passageway communicating with the sheet input tray;    a first sub-passageway communicating with the main passageway and the second passageway;    a second sub-passageway communicating with the main passageway and the third passageway; and    a main/sub-passageway guiding rod for switchably guiding the first sheet from the main passageway through the first sub-passageway or the second sub-passageway.    
   
   
       3 . The automatic sheet feeder according to  claim 2 , further comprising: 
 a first temporary storage region selectively communicating with the first sub-passageway and the second passageway, the first sheet from the first sub-passageway being temporarily stored in the first temporary storage region; and    a first guiding rod for switchably guiding the first sheet from the first sub-passageway to the first temporary storage region, and guiding the first sheet from the first temporary storage region to the second passageway.    
   
   
       4 . The automatic sheet feeder according to  claim 3 , further comprising: 
 a second temporary storage region selectively communicating with the second sub-passageway and the third passageway, the first sheet from the second sub-passageway being temporarily stored in the second temporary storage region; and    a second guiding rod for switchably guiding the first sheet from the second sub-passageway to the second temporary storage region, and guiding the first sheet from the second temporary storage region to the third passageway.    
   
   
       5 . The automatic sheet feeder according to  claim 4 , wherein the main passageway is formed with an image processing region.  
   
   
       6 . The automatic sheet feeder according to  claim 5 , further comprising a scanning module opposite to the image processing region for scanning the first sheet passing through the image processing region.  
   
   
       7 . The automatic sheet feeder according to  claim 5 , further comprising a printing module opposite to the image processing region for printing the first sheet passing through the image processing region.  
   
   
       8 . The automatic sheet feeder according to  claim 5 , wherein the sheet-feeding mechanism comprises: 
 a sheet-input roller for feeding the first sheet from the sheet input tray to the main passageway;    a first roller set located on the main passageway for assisting in feeding the first sheet from the sheet input tray to the first sub-passageway, and assisting in feeding the first sheet from the second passageway to the second sub-passageway;    a second roller set for feeding the first sheet from the first sub-passageway to the first temporary storage region, and feeding the first sheet from the first temporary storage region to the second passageway;    a third roller set for feeding the first sheet from the second sub-passageway to the second temporary storage region, and feeding the first sheet from the second temporary storage region to the third passageway; and    a sheet-output roller set for feeding the first sheet from the third passageway to the sheet output tray.    
   
   
       9 . The automatic sheet feeder according to  claim 1 , further comprising: 
 a temporary storage region selectively communicating with the first passageway and the second passageway, the first sheet of the first passageway being temporarily stored in the temporary storage region; and    a first guiding rod for switchably guiding the first sheet from the first passageway to the temporary storage region, and guiding the first sheet from the temporary storage region to the second passageway.    
   
   
       10 . The automatic sheet feeder according to  claim 9 , further comprising: 
 a second guiding rod for switchably guiding the first sheet from the first passageway to the temporary storage region or the third passageway.    
   
   
       11 . The automatic sheet feeder according to  claim 10 , wherein the first passageway is formed with an image processing region.  
   
   
       12 . The automatic sheet feeder according to  claim 11 , further comprising a scanning module opposite to the image processing region for scanning the first sheet passing through the image processing region.  
   
   
       13 . The automatic sheet feeder according to  claim 11 , further comprising a printing module opposite to the image processing region for printing the first sheet passing through the image processing region.  
   
   
       14 - 15 . (canceled)  
   
   
       16 . The automatic sheet feeder according to  claim 1 , wherein the sheet-feeding mechanism further has a simplex sheet-feeding mode, in which the sheet-feeding mechanism feeds the first sheet from the sheet input tray through the first passageway and finally to the sheet output tray, a relative order between the first sheet and the second sheet is kept unchanged after the first and second sheets are fed in the simplex sheet-feeding mode or the duplex sheet-feeding mode.  
   
   
       17 - 31 . (canceled)