Sheet-conveying mechanism

Abstract

A sheet transport guide includes a torsion coil spring (X). The spring (X) has a first arm (B 4 ) with an end (B 5 ). Through the end (B 5 ), the spring (X) supports a rotation shaft of driven roller (R 32 ) and applies elastic force to the roller (R 32 ). Through the arm (B 4 ) that is curved, the spring (X) guides a sheet toward a rotation roller R 31. The spring (X) has a coil portion (B 1 ) and an end (B 3 ) of a second arm (B 3 ) both fixed to a frame of an apparatus body. A plurality of driven rollers (R 32 ) are aligned approximately parallel to a shaft (R 31 a ) of the roller (R 31 ). The rollers (R 32 ) are each provided with the springs (X). A largest elastic force is applied to the roller (R 32 ) at a predetermined reference position, and smaller elastic forces are applied to the other rollers (R 32 ) at positions distant from the reference position.

1 ) A sheet transport mechanism, comprising: 
 a rotation roller;    a movable member; and    a sheet transport guide for guiding toward and/or away from the rotation roller a sheet to be transported between the rotation roller and the movable member, the sheet transport guide including an elastic member and having a portion connected to the movable member,    wherein the sheet transport guide applies elastic force to the movable member so that the movable member is elastically biased toward the rotation roller.    
   
   
       2 ) A sheet transport mechanism according to  claim 1 , wherein the elastic member is a torsion coil spring having first and second arms for guiding a sheet to be transported.  
   
   
       3 ) A sheet transport mechanism according to  claim 2 , wherein the movable member is a driven roller that is rotated in association with rotation of the rotation roller.  
   
   
       4 ) A sheet transport mechanism according to  claim 3 , wherein the driven roller is supported by the first arm of the torsion coil spring.  
   
   
       5 ) A sheet transport mechanism according to  claim 2 , wherein the movable member is a separation pad for feeding one sheet at a time.  
   
   
       6 ) A sheet transport mechanism according to  claim 5 , wherein the separation pad is supported by a coil portion of the torsion coil spring.  
   
   
       7 ) A sheet transport mechanism according to  claim 4 , wherein a plurality of the movable members are aligned approximately parallel to a shaft of the rotation roller, and wherein each of the movable members is provided with the sheet transport guide.  
   
   
       8 ) A sheet transport mechanism according to  claim 7 , wherein the sheet transport guide positioned at a predetermined reference position is adjusted to have a larger elastic force than any one of the sheet transport guides positioned at positions distant from the reference position have.  
   
   
       9 ) A sheet transport mechanism according to  claim 8 , wherein the sheet transport guides are adjusted to have respective elastic forces that become progressively smaller with distance from the reference position.  
   
   
       10 ) A sheet transport mechanism according to  claim 8 , wherein the reference position is located in an approximately central part of the shaft of the rotation roller.  
   
   
       11 ) A sheet transport mechanism according to  claim 8 , wherein the reference position is located in either one of opposite end portions of the shaft of the rotation roller.