Apparatus for detecting front edge of a document and determining the home position of an image scanning module

Abstract

An apparatus for detecting front edge of a document and determining home position of an image scanning module has a detecting light source near an outlet end of a document feeding track and aligned with an image reader of the image scanning module. The detecting light source emits a detecting light to be received by the image reader. By detecting whether the detecting light is received by the image reader, the front edge of the document can be detected to activate the image scanning module. And it can also determine whether or not the image scanning module has arrived on a home position.

1 . An apparatus for detecting front edge of a document that is installed on a scanning device to detect the front edge of the document, comprising: 
 an image scanning module which includes an image reader and a scanning light source;    a document feeding track which has an inlet end for feeding documents sequentially into the document feeding track and an outlet end for receiving the documents discharged from a paper path of the document feeding track corresponding to the image scanning module; and    a detecting light source located on the document feeding track and over which the document passes corresponding to the image reader to emit a detecting light which is received by the image reader;    wherein when the front edge of the document arrives between the image reader and the detecting light source to block the detecting light, the image scanning module is activated and the scanning light source starts emitting a scanning light to perform a scanning operation.    
   
   
       2 . The apparatus of  claim 1 , wherein the scanning device includes a housing which has a scanning platform on an upper side, the image scanning module being located under the scanning platform.  
   
   
       3 . The apparatus of  claim 2 , wherein the document feeding track has a scanning window corresponding to one side of the scanning platform and opposite to the image scanning module.  
   
   
       4 . The apparatus of  claim 2  further comprising a conveying module located under the scanning platform to drive the image scanning module to move back and forth under the scanning platform.  
   
   
       5 . The apparatus of  claim 4 , wherein the conveying module includes a motor and a conveying element, the conveying element is coupled with the motor and the image scanning module.  
   
   
       6 . The apparatus of  claim 5  further comprising a control circuit to control the image scanning module and the motor.  
   
   
       7 . The apparatus of  claim 1  further comprising a plurality of feeding rollers which are located on two sides of the document feeding track and rotate to drive the document from the inlet end of the document feeding track towards the outlet end.  
   
   
       8 . The apparatus of  claim 1 , wherein the document feeding track has a detecting window over which the document passes corresponding to the image reader, the detecting light source being located in the detecting window.  
   
   
       9 . A scanning device equipped with an apparatus for determining the home position of an image scanning module, comprising: 
 a housing having a scanning platform on an upper surface;    an image scanning module which is located under the scanning platform, having an image reader and a scanning light source;    a conveying module to drive the image scanning module to move back and forth from a home position under the scanning platform; and    a detecting light source which is located above the scanning platform corresponding to the home position of the image scanning module, to emit a detecting light to be received by the image reader.    
   
   
       10 . The scanning device of  claim 9 , wherein the conveying module includes a motor and a conveying element, the conveying element is coupled with the motor and the image scanning module.  
   
   
       11 . The scanning device of  claim 10  further comprising a control circuit to control operations of the image scanning module and the motor.  
   
   
       12 . An automatic document feeding mechanism, comprising: 
 a document feeding track which has an inlet end and an outlet end, to receive a document from the inlet end moving towards the outlet; and    a detecting light source located on the document feeding track and over which the document passes to emit a detecting light.    
   
   
       13 . The automatic document feeding mechanism of  claim 12  further comprising a plurality of feeding rollers located on two sides of the document feeding track rotating to drive a document from the inlet end of the document feeding track moving towards the outlet end.  
   
   
       14 . The automatic document feeding mechanism of  claim 12 , wherein the document feeding track has a detecting window over which the document passes, the detecting light source being located in the detecting window.  
   
   
       15 . The automatic document feeding mechanism of the  claim 12 , wherein the detecting light source is located near the outlet end of the document feeding track.