Paper-feeding device with automatic paper detecting function

Abstract

A paper-feeding device includes a paper tray for holding paper, a paper advance module for picking up the paper held on the paper tray and outputting the paper, a sensing module for sensing the deformation of the paper during the feeding process and outputting a sensing signal when the paper advances in a sensing area, and a control unit for determining the paper feeding status according to the sensing signal generated from the sensing module.

1 . A paper-feeding device comprising: 
 a paper tray for holding paper;    a paper advance module for picking up the paper held on the paper tray and outputting the paper;    a sensing module for sensing the deformation of the paper during the feeding process and outputting a sensing signal when the paper advances in a sensing area; and    a control unit for determining the paper feeding status according to the sensing signal generated from the sensing module.    
   
   
       2 . The paper-feeding device of  claim 1  wherein the paper advance module further comprises: 
 a pickup roller installed above the paper tray in a rotatable manner for picking up the paper held on the paper tray;    a feed roller installed in front of the bottom of the paper tray in a rotatable manner for driving the paper to move in an advancing direction; and    a motor for driving the pickup roller and the feed roller.    
   
   
       3 . The paper-feeding device of  claim 1  further comprising a paper holder for holding the paper before the paper advances in the sensing area.  
   
   
       4 . The paper-feeding device of  claim 1  wherein the motor is a stepping motor.  
   
   
       5 . The paper-feeding device of  claim 1  wherein the motor is a DC motor.  
   
   
       6 . The paper-feeding device of  claim 1  wherein the sensing module outputs a sensing signal according to a buckling deformation of the paper during the feeding process.  
   
   
       7 . The paper-feeding device of  claim 6  further comprising a paper constrainer for constraining the buckling deformation of the paper during the feeding process.  
   
   
       8 . The paper-feeding device of  claim 7  wherein the distance between the paper constrainer and the sensing module is less than 5 mm.  
   
   
       9 . The paper-feeding device of  claim 6  wherein the sensing module is a reflective-type sensor for emitting a sensing signal to the paper and receiving the sensing signal reflected from the paper to calculate the deformation of the paper.  
   
   
       10 . The paper-feeding device of  claim 6  wherein the control unit comprises an amplifier for amplifying the buckling deformation of the paper detected by the sensing module, and an analog-to-digital converter for converting analog signals outputted from the amplifier into digital signals.  
   
   
       11 . The paper-feeding device of  claim 1  wherein the sensing module comprises: 
 a transmission link with one end used to contact the paper;    a spring sheathed on the transmission link; and    a deformation sensor installed on the spring for sensing deformation of the spring tugged by the deformation of the paper during the feeding process.    
   
   
       12 . The paper-feeding device of  claim 11  wherein the deformation sensor is a strain gauge.  
   
   
       13 . The paper-feeding device of  claim 11  wherein the deformation sensor is a sensor made of piezoelectric material.  
   
   
       14 . The paper-feeding device of  claim 1  wherein the control unit can output a feedback signal to the paper advance module for modifying action of the paper advance module according the sensing signal outputted by the sensing module.  
   
   
       15 . The paper-feeding device of  claim 14  wherein when the paper advance module receives the feedback signal transmitted from the control unit, the paper advance module stops the feeding process.  
   
   
       16 . A paper-feeding method comprising: 
 feeding a paper;    outputting a sensing signal according to deformation of the paper during the feeding process; and    determining whether the paper advances normally or not according to the sensing signal.    
   
   
       17 . The method of  claim 16  further comprising if the paper advances normally, continuing feeding the paper until the paper slides out completely, and if the paper advances abnormally, stopping the feeding process.  
   
   
       18 . The method of  claim 16  wherein the deformation of the paper during the feeding process is a buckling deformation.