Sheet conveying device

Abstract

A sheet conveying device for in an image forming apparatus includes a first guide. A second guide faces the first guide to define a sheet conveyance passage therebetween. A driving shaft is mounted on the first guide and carries driving rollers. A supporting shaft extends substantially orthogonal to a sheet conveying direction. Driven rollers are at opposite ends of the supporting shaft and correspond to the driving rollers. A holder holds the supporting shaft so that the supporting shaft can move towards the driving shaft. Urging members are at opposite sides of an axially center of the supporting shaft for pushing the driven rollers against the driving rollers. The holder is attached to the second guide to swing at a pivotal axis extending in the sheet conveying direction, the pivotal axis is on a plane orthogonally passing the supporting shaft at a center thereof.

1 . A sheet conveying device for conveying a sheet, which is to be installed in an image forming apparatus for forming an image on a sheet, comprising: 
 a first guide member;    a second guide member facing the first guide member so as to define a sheet conveyance passage therebetween;    a driving shaft mounted on the first guide member and carrying driving rollers;    a supporting shaft extending in a direction substantially orthogonal to a sheet conveying direction, the supporting shaft rotatably supporting driven rollers at opposite ends thereof, the driven rollers corresponding to the driving rollers, respectively;    a holder for holding the supporting shaft in such a manner that the supporting shaft is able to move toward the driving shaft; and    urging members provided at opposite sides of an axially center of the supporting shaft for urging the supporting shaft in a direction of pushing the driven rollers against the driving rollers, wherein the holder is attached to the second guide member in such a manner that the holder is able to swing at a pivotal axis extending in the sheet conveying direction, the pivotal axis is on a plane orthogonally passing the supporting shaft at a center thereof.    
   
   
       2 . A sheet conveying device according to  claim 1 , wherein the holder has a bearing recess which is opened toward the driving shaft and in which the supporting shaft is placed movably toward the driving shaft.  
   
   
       3 . A sheet conveying device according to  claim 2 , wherein the holder has a shaft restrainer in a position closer to the driving shaft than the supporting shaft placed in the bearing recess for keeping the supporting shaft from leaving from the bearing recess.  
   
   
       4 . A sheet conveying device according to  claim 3 , wherein the shaft restrainer includes restraining projections on opposite walls of the bearing recess, the opposite walls face each other in the sheet conveying direction, and a gap between the restraining projections is smaller than a diameter of the supporting shaft under a specified pressure, but the gap is expandable owing to elastic shifts of the opposite walls when being applied with a pressure greater than the specified pressure.  
   
   
       5 . A sheet conveying device according to  claim 1 , the second guide member includes a pair of retainers which are opposite to each other in the sheet conveying direction and are adapted for retaining the holder swingably.  
   
   
       6 . A sheet conveying device according to  claim 5 , wherein the pivotal axis is defined by an engagement of a pivotal stem formed on an outer surface of the holder and a pivotal hole formed in an inner surface of the retainer or an engagement of a pivotal stem formed on the inner surface of the retainer and a pivotal hole formed in the outer surface of the holder.  
   
   
       7 . A sheet conveying device according to  claim 6 , wherein the retainer is elastically shiftable in the sheet conveying direction.  
   
   
       8 . A sheet conveying device according to  claim 6 , wherein a plurality of pivotal holes are provided in a direction parallel with a plane orthogonally passing the respective axes of the driving shaft and supporting shaft.  
   
   
       9 . An image forming apparatus comprising a sheet conveying device provided with: 
 a first guide member;    a second guide member facing the first guide member so as to define a sheet conveyance passage therebetween;    a driving shaft mounted on the first guide member and carrying driving rollers;    a supporting shaft extending in a direction substantially orthogonal to a sheet conveying direction, the supporting shaft rotatably supporting driven rollers at opposite ends thereof, the driven rollers corresponding to the driving rollers, respectively;    a holder for holding the supporting shaft in such a manner that the supporting shaft is able to move toward the driving shaft;    urging members provided at opposite sides of an axially center of the supporting shaft for urging the supporting shaft in a direction of pushing the driven rollers against the driving rollers, wherein the holder is attached to the second guide member in such a manner that the holder is able to swing at a pivotal axis extending in the sheet conveying direction, the pivotal axis is on a plane orthogonally passing the supporting shaft at a center thereof.