Paper feeding mechanism

Abstract

A paper feeding mechanism for automatically adjusting paper supply force includes a swing gear assembly, a lifting plate, and a cam. The swing gear assembly provides a driving force for automatic control, turning the cam to lift or lower the lifting plate and paper, and fine-tuning the lifting force for paper supply to avoid paper miss-feeds or multi-feeds.

What is claimed is:  
     
         1 . A paper feeding mechanism for supplying paper to a pickup roller to pick up, comprising: 
 a swing gear assembly which includes a plurality of gears and at least one linkage bar and has one end fixed and other end swingable to transmit rotational driving power from a driving power source;    a lifting plate for holding paper having one end fixed and other end movable; and    a cam selectively engaged with the swingable end of the swing gear assembly to rotate; and    means for driving the lifting plate, wherein the cam is turned to lift or lower the movable end of the lifting plate to change the relative distance and a contact force between the paper held on the lifting plate and the pickup roller.    
     
     
         2 . The paper feeding mechanism of  claim 1 , wherein the cam has gear teeth formed on the peripheral surface thereof.  
     
     
         3 . The paper feeding mechanism of  claim 1 , wherein the cam is coaxial with a gear and the movable end of the swing gear assembly is selectively engaged with the gear.  
     
     
         4 . The paper feeding mechanism of  claim 1 , wherein the driving means is to locate the cam below the lifting plate, and to rotate the cam to lift or lower the movable end of the lifting plate.  
     
     
         5 . The paper feeding mechanism of  claim 4  further comprising an elastic element located between the lifting plate and the cam.  
     
     
         6 . The paper feeding mechanism of  claim 5 , wherein the elastic element is a spring.  
     
     
         7 . The paper feeding mechanism of  claim 1 , wherein the driving means is to have the movable end of the lifting plate connecting to a swingable end of an arm, the arm having other end fixed, the cam being located below the arm and rotatable to lift or lower the movable end of the lifting plate through the arm.  
     
     
         8 . The paper feeding mechanism of  claim 7 , wherein the arm is connected to the lifting plate through an elastic element.  
     
     
         9 . The paper feeding mechanism of  claim 8 , wherein the elastic element is a spring or an elastic string.  
     
     
         10 . The paper feeding mechanism of  claim 1 , wherein the lifting plate has a straddle section on one side, the cam being located below the straddle section, the method for driving is to turn the cam to push the straddle section to lift or lower the movable end of the lifting plate.  
     
     
         11 . A paper feeding mechanism for supplying paper to a pickup roller to pick up, comprising: 
 a swing gear assembly which includes a plurality of gears and at least one linkage bar and has one end fixed and other end swingable to transmit rotational driving power from a driving power source;    a lifting plate for holding paper having one end fixed and other end movable; and    a cam selectively engaged with the swingable end of the swing gear assembly and rotatable to lift or lower the movable end of the lifting plate to change the relative distance and a contact force between the paper held on the lifting plate and the pickup roller.    
     
     
         12 . The paper feeding mechanism of  claim 11 , wherein the cam has gear teeth formed on the peripheral surface thereof.  
     
     
         13 . The paper feeding mechanism of  claim 11 , wherein the cam is coaxial with a gear and the movable end of the swing gear assembly is selectively engaged with the gear.  
     
     
         14 . The paper feeding mechanism of  claim 11 , wherein the cam is located below the lifting plate such that the movable end of the lifting plate is lifted or lowered when the cam rotates.  
     
     
         15 . The paper feeding mechanism of  claim 14  further comprising an elastic element located between the lifting plate and the cam.  
     
     
         16 . The paper feeding mechanism of  claim 15 , wherein the elastic element is a spring.  
     
     
         17 . The paper feeding mechanism of  claim 11 , wherein the movable end of the lifting plate is connected to a swingable end of an arm, the arm having other end fixed, the cam being located below the arm.  
     
     
         18 . The paper feeding mechanism of  claim 17 , wherein the arm is connected to the lifting plate through an elastic element.  
     
     
         19 . The paper feeding mechanism of  claim 18 , wherein the elastic element is a spring or an elastic string.  
     
     
         20 . The paper feeding mechanism of  claim 11 , wherein the lifting plate has a straddle section on one side, the cam being located below the straddle section and rotatable to push the straddle section to lift or lower the movable end of the lifting plate.