Medium ejection device

Abstract

A medium ejection device includes a housing, an ejection roller, an opposing roller, and a tray. The housing includes: a medium conveyance path tilted to be lower toward a downstream end of the path in a medium ejecting direction to eject a medium downward; and a wall portion disposed below a nip surface between the ejection roller and the opposing roller. The wall portion is not overlapped, when viewed from a direction perpendicular to the medium ejecting direction, with a circle that is centered at an intersection point between an extension line of the nip surface and a placement surface of the tray and passes through a point closest to the intersection point on outer circumference surfaces of the ejection roller and the opposing roller such that, when the ejected medium falls down, a rear end of the medium does not come into contact with the wall portion.

1 . A medium ejection device, comprising:
 a housing;   an ejection roller disposed in the housing to eject a medium;   an opposing roller opposed to the ejection roller; and   a tray disposed in the housing to stack the medium ejected by the ejection roller,   the housing including:
 a medium conveyance path tilted such that the medium conveyance path is lower toward a downstream end of the medium conveyance path in a medium ejecting direction to eject the medium downward; and 
 a wall portion disposed below a nip surface between the ejection roller and the opposing roller, the wall portion not overlapped, when viewed from a direction perpendicular to the medium ejecting direction, with a circle that is centered at an intersection point between an extension line of the nip surface of the ejection roller and the opposing roller and a placement surface of the tray and passes through a point closest to the intersection point on outer circumference surfaces of the ejection roller and the opposing roller such that, when the medium ejected by the ejection roller falls down, a rear end of the medium does not come into contact with the wall portion. 
   
     
     
         2 . The medium ejection device according to  claim 1 ,
 wherein the tray includes a first placement surface on which at least a part of the medium ejected by the ejection roller is placed, and   the housing includes a second placement surface that is connected to the wall portion and on which at least another part of the medium ejected by the ejection roller is placed.   
     
     
         3 . The medium ejection device according to  claim 1 ,
 wherein at least one of the opposing roller or the ejection roller further includes an elastic roller disposed on an outer circumference surface of the at least one of the opposing roller or the ejection roller.   
     
     
         4 . The medium ejection device according to  claim 1 ,
 wherein the wall portion is disposed so as not to be overlapped with an involute curve that has, as a base circle, a circle passing through a first position located upstream from the intersection point in the medium ejecting direction on the placement surface of the tray and a second position closest to the first position on the outer circumference surfaces of the ejection roller and the opposing roller when viewed from a direction perpendicular to the medium ejecting direction.   
     
     
         5 . The medium ejection device according to  claim 1 ,
 wherein the wall portion is mirror polished or fluororesin coated.   
     
     
         6 . The medium ejection device according to  claim 1 ,
 wherein the wall portion includes a plurality of holes.   
     
     
         7 . The medium ejection device according to  claim 6 ,
 wherein the plurality of holes are disposed in the housing at positions closer to a lowest end of the ejection roller and the opposing roller than the placement surface of the tray.   
     
     
         8 . The medium ejection device according to  claim 6 , further comprising:
 a motor to rotate a roller to convey the medium; and   a blade disposed in the housing to rotate with rotation of the motor.   
     
     
         9 . The medium ejection device according to  claim 6 ,
 wherein the placement surface of the tray is tilted such that the placement surface is lower toward an upstream end of the placement surface in the medium ejecting direction.   
     
     
         10 . The medium ejection device according to  claim 6 ,
 wherein the plurality of holes are arranged in a staggered pattern.   
     
     
         11 . The medium ejection device according to  claim 6 ,
 wherein the plurality of holes have opening areas per unit area that are larger toward the bottom.   
     
     
         12 . The medium ejection device according to  claim 6 ,
 wherein the plurality of holes have opening areas per unit area that are larger at outer positions in the direction perpendicular to the medium ejecting direction.   
     
     
         13 . The medium ejection device according to  claim 6 ,
 wherein the tray has a recessed portion disposed at an upstream end of the placement surface of the tray in the medium ejecting direction or at an end of the placement surface of the tray in the direction perpendicular to the medium ejecting direction.   
     
     
         14 . The medium ejection device according to  claim 6 ,
 wherein another wall portion different from the wall portion includes a plurality of holes.