Paper feeder enabling proper feeding alignment

Abstract

A paper feeder including a pickup roller, a separation roller, a separation pad, a pressing device, and a separation plate is provided. The separation roller is located downstream the pickup roller. The separation pad leaning on the separation roller has a curved separation portion. The pressing device has a spherical node. The separation plate has a cavity on a back thereof for allocating the spherical node, and it also has a V-shaped slit on a front thereof for pressing the separation pad on the separation roller. As the spherical node is pressed on the separation pad, the V-shaped slit is guided to parallel to the shaft of the separation roller so as to have the separation pad precisely assembled on the surface of the separation roller.

1 . A paper feeder comprising:
 a pickup roller, for driving a sheet of paper;   a separation roller, located downstream the pickup roller, having a shaft;   a separation pad, having a curved separation portion leaning to the separation roller;   a pressing device, having a spherical node; and   a separation plate, having a cavity on a back thereof for allocating the spherical node, and a V-shaped slit on a front thereof for pressing the separation pad on the separation roller;   wherein as the spherical node is pressed on the separation plate, the V-shaped slit is guided to be parallel to the shaft of the separation roller to have the curved separation portion leaning on the separation roller.   
     
     
         2 . The paper feeder of  claim 1 , wherein the pressing device further having an elastic unit for providing force to have the spherical node pressing on the separation plate. 
     
     
         3 . The paper feeder of  claim 2 , wherein the pressing device further having a basis and a gap adjusting screw, wherein the basis has an opening to have the spherical node protruding downward in contact with the separation plate, and the gap adjusting screw is screwed fixed to the basis and touches a rear end of the spherical node for adjusting a gap between the separation pad and the separation roller. 
     
     
         4 . The paper feeder of  claim 3 , wherein the pressing device further having a force adjusting screw screwed fixed to the gap adjusting screw and pushed against the elastic unit for adjusting the force provided by the elastic unit. 
     
     
         5 . The paper feeder of  claim 3 , wherein the separation plate is movably assembled to the basis of the pressing device and is fixed on the basis by the gap adjusting screw. 
     
     
         6 . The paper feeder of  claim 5 , wherein the separation pad is movably assembled to the separation plate. 
     
     
         7 . The paper feeder of  claim 1 , wherein the cavity has a curved surface with a curvature smaller than that of the spherical node. 
     
     
         8 . The paper feeder of  claim 1 , wherein the cavity has a spherical surface. 
     
     
         9 . The paper feeder of  claim 1 , further comprising a calibration pad utilized for interposing into the gap between the separation pad and the separation roller for adjusting the size of the gap. 
     
     
         10 . The paper feeder of  claim 9 , wherein the calibration pad has a thickness ranged between one sheet of paper and two sheets of paper. 
     
     
         11 . An automatic document feeder (ADF) comprising:
 a paper tray, for placing at least a sheet of paper;   a paper feeder having:
 a pickup roller, for driving the sheet of paper; 
 a separation roller, located downstream the pickup roller, having a shaft; 
 a separation pad, having a curved separation portion leaning to the separation roller; 
 a pressing device, having a spherical node; and 
 a separation plate, having a cavity on a back thereof for allocating the spherical node, and a V-shaped slit on a front thereof for pressing the separation pad on the separation roller; 
 wherein as the spherical node is pressed on the separation plate, the V-shaped slit is guided to be parallel to a shaft of the separation roller to have the curved separation portion leaning on the separation roller; 
   a midway roller set, located downstream the paper feeder, for taking the sheet of paper away from the paper feeder to a scanning or printing position; and   an exit roller set, located downstream the midway roller set, for taking the sheet of paper away from the scanning or printing position and for outputting the sheet of paper.   
     
     
         12 . The ADF of  claim 11 , wherein the pressing device further having an elastic unit for providing force to have the spherical node pressing on the separation plate. 
     
     
         13 . The ADF of  claim 12 , wherein the pressing device further having a basis and a gap adjusting screw, wherein the basis has an opening to have the spherical node protruding downward in contact with the separation plate, and the gap adjusting screw is screwed fixed to the basis and touches a rear end of the spherical node for adjusting a gap between the separation pad and the separation roller. 
     
     
         14 . The ADF of  claim 13 , wherein the pressing device further having a force adjusting screw screwed fixed to the gap adjusting screw and pushed against the elastic unit for adjusting the force provided by the elastic unit. 
     
     
         15 . The ADF of  claim 13 , wherein the separation plate is movably assembled to the basis of the pressing device and is fixed on the basis by the gap adjusting screw. 
     
     
         16 . The ADF of  claim 15 , wherein the separation pad is movably assembled to the separation plate. 
     
     
         17 . The ADF of  claim 11 , wherein the cavity has a curved surface with a curvature smaller than that of the spherical node. 
     
     
         18 . The ADF of  claim 11 , wherein the cavity a spherical surface. 
     
     
         19 . The ADF of  claim 11 , further comprising a calibration pad utilized for interposing into the gap between the separation pad and the separation roller for adjusting the size of the gap. 
     
     
         20 . The ADF of  claim 19 , wherein the calibration pad has a thickness ranged between one sheet of paper and two sheets of paper.