Adjustable feed mechanism for various media

Abstract

A media feed mechanism in a printer is provided. The media feed mechanism includes a drive roller for feeding a print medium in the printer, a pinch roller coupled to the drive roller for feeding the print media between the drive roller and the pinch roller, and a spring operatively connected to the pinch roller for biasing the pinch roller against the drive roller to exert a pinch force on the drive roller. Such a pinch force ensures that the print medium remains in contact with and is properly fed by the drive roller. The media feed mechanism further includes means connected to the spring for altering at least one character of the biasing force provided by the spring so as to alter the pinch force exerted on the drive roller.

What is claimed is:  
     
         1 . A media feed mechanism in a printer, comprising: 
 a drive roller for feeding a print medium in the printer;    a pinch roller coupled to the drive roller for feeding the print media between the drive roller and the pinch roller;    a spring operatively connected to the pinch roller for biasing the pinch roller against the drive roller to exert a pinch force on the drive roller, said pinch force ensuring that the print medium remains in contact with and is properly fed by the drive roller; and    means connected to the spring for altering the biasing force provided by the spring so as to alter the pinch force exerted on the drive roller.    
     
     
         2 . The media feed mechanism of  claim 1 , wherein said means includes a linkage rod to which an end of the spring attaches, and a driving means for driving the linkage rod between a first and a second positions in the printer so as to alter the biasing force.  
     
     
         3 . The media feed mechanism of  claim 2 , further comprising a securing means for securing the linkage rod in one of the first and the second positions.  
     
     
         4 . The media feed mechanism of  claim 3 , wherein the linkage rod is substantially parallel to a shaft about which the drive roller rotates.  
     
     
         5 . The media feed mechanism of  claim 4 , wherein the profile is designed to be in an arcuate shape.  
     
     
         6 . The media feed mechanism of  claim 2 , wherein the driving means includes a lever that is connected to the linkage rod and protrudes outside the printer for manual operation, the lever being manually operable so as to drive the linkage rod between the first and the second positions.  
     
     
         7 . The media feed mechanism of  claim 6 , wherein the lever is rotatable about an axle, wherein the linkage rod is movable along a profile in an semicircular shape, and wherein an axis of the axle passes through a center of the profile.  
     
     
         8 . The media feed mechanism of  claim 1 , further comprising a pinch-roller-holder, with the pinch roller mounted at one end and the spring attached to the other end thereof, wherein the spring applies a torque to the pinch-roller-holder so as to bias the pinch roller against the drive roller.