Driven roller, transport roller device, and liquid ejecting apparatus

Abstract

A driven roller operates together with a driving roller to form a nip area for a medium to be transported. The driven roller includes a roller shaft and a roller element having a through hole through which the roller shaft extends. A contact position at which the roller shaft and an inner surface of the through hole are in contact with each other is located within the nip area.

1 . A driven roller that operates together with a driving roller to form a nip area for a medium to be transported, the driven roller comprising:
 a roller shaft; and   a roller element having a through hole through which the roller shaft extends,   wherein a contact position at which the roller shaft and an inner surface of the through hole are in contact with each other is located within the nip area.   
     
     
         2 . The driven roller according to  claim 1 , wherein the driven roller has a convexly curved outer surface so that an outer circumference of the driven roller at the center thereof in an axial direction is larger than an outer circumference of the driven roller at ends thereof in the axial direction. 
     
     
         3 . The driven roller according to  claim 1 , wherein the contact position at which the roller shaft and the inner surface of the through hole are in contact with each other is located in a central area of the roller element in an axial direction. 
     
     
         4 . The driven roller according to  claim 1 , wherein the through hole has a small-diameter portion and a large-diameter portion, and the small-diameter portion is at the contact position. 
     
     
         5 . The driven roller according to  claim 4 , wherein the through hole has a symmetrical shape in an axial direction about a central portion of the roller element. 
     
     
         6 . A transport roller device, comprising:
 a driving roller;   a driven roller that operates together with the driving roller to form a nip area for a medium to be transported; and   a pressing-force applying unit that applies a relative pressing force between the driving roller and the driven roller,   wherein the driven roller includes
 a roller shaft, and 
 a roller element having a through hole through which the roller shaft extends, 
 wherein a contact position at which the roller shaft and an inner surface of the through hole are in contact with each other in the driven roller is located within the nip area. 
   
     
     
         7 . The transport roller device according to  claim 6 , wherein the driven roller has a convexly curved outer surface so that an outer circumference of the driven roller at the center thereof in an axial direction is larger than an outer circumference of the driven roller at ends thereof in the axial direction. 
     
     
         8 . The transport roller device according to  claim 6 , wherein the contact position at which the roller shaft and the inner surface of the through hole are in contact with each other is located in a central area of the roller element in an axial direction. 
     
     
         9 . A liquid ejecting apparatus, comprising:
 a transporting unit that transports a medium to be transported;   a liquid ejecting unit that ejects liquid toward the medium; and   an ejecting unit that ejects the medium after the liquid is ejected toward the medium,   wherein the transporting unit includes the transport roller device according to  claim 6 .