Sheet conveying device and image forming apparatus with the same

Abstract

A sheet conveying device ( 30 ) includes a plurality of first conveyance rollers ( 31 ) and a plurality of second conveyance rollers ( 32 ). The sheet conveying device ( 30 ) includes stiffening rollers ( 34 ). The stiffening rollers ( 34 ) are disposed coaxially with at least one conveyance rollers ( 32 ) among the first and second conveyance rollers ( 31 ) and ( 32 ), and have diameters larger than diameters of the conveyance rollers ( 32 ). The stiffening rollers ( 34 ) includes first stiffening rollers ( 34 a ), which apply conveying forces to a sheet (P), and second stiffening rollers ( 34 b ), which apply smaller conveying forces to the sheet (P) than the conveying forces to the sheet (P) in the first stiffening rollers ( 34 a ).

1 . A sheet conveying device comprising:
 a plurality of first conveyance rollers;   a plurality of second conveyance rollers that face, one by one, the plurality of first conveyance rollers, the plurality of second conveyance rollers conveying a sheet while sandwiching the sheet between the second conveyance rollers and the first conveyance rollers; and   a stiffening roller disposed coaxially with either or both of the first and second conveyance rollers, the stiffening roller having a diameter larger than a diameter of either or both of the first and second conveyance rollers that are disposed coaxially,   wherein   either of the first or second conveyance rollers are fixed on a single drive roller shaft, and   the other of the first or second conveyance rollers are fixed on a driven roller shaft and arranged in an axial direction of the driven roller shaft.   
     
     
         2 . The sheet conveying device according to  claim 1 , wherein
 the stiffening roller includes a first stiffening roller and a second stiffening roller,   either of the first stiffening roller or the second stiffening roller has a rubber surface, and   the other of the first stiffening roller or the second stiffening roller has a resin surface.   
     
     
         3 . The sheet conveying device according to  claim 1 , wherein
 the stiffening roller includes a first stiffening roller and a second stiffening roller,   the first stiffening roller is configured to integrally rotate with the conveyance rollers, and   the second stiffening roller is configured to freely rotate with respect to the conveyance rollers.   
     
     
         4 . The sheet conveying device according to  claim 1 , wherein
 the stiffening roller includes a first stiffening roller and a second stiffening roller, and   the first stiffening roller and the second stiffening roller have a same outer diameter.   
     
     
         5 . The sheet conveying device according to  claim 1 , wherein
 the stiffening roller includes a first stiffening roller and a second stiffening roller, and   a conveying force applied to the sheet by the second stiffening roller due to surface friction is smaller than a conveying force applied to the sheet by the first stiffening roller due to surface friction.   
     
     
         6 . The sheet conveying device according to  claim 5 , wherein
 the first stiffening roller has a rubber surface, and   the second stiffening roller has a resin surface.   
     
     
         7 . An image forming apparatus comprising the sheet conveying device according to  claim 1 .