Sheet feeder and printer

Abstract

A paper feeding apparatus according to the present invention has a pickup roller, which includes a drive shaft disposed so as to cross a sheet tray and a plurality of roller parts intermittently attached to the drive shaft, and elastic supporting means, which substantially independently supports a plurality of exposed parts of the drive shaft so as to apply pressure towards a base plate of the sheet tray. In the paper feeding apparatus, respective exposed parts of the drive shaft, which has a narrow diameter and being flexible, are independently pressurized towards the sheet tray of the base plate, so that the respective roller parts contact tightly with the sheets substantially independently. Accordingly, sheets can be fed with high reliability by making the most of the flexibility of the drive shaft. The extremely slim and highly reliable paper feeding apparatus with the extremely slim pickup roller is provided. By stacking a plurality of these paper feeding apparatuses, a compact multitray can be provided.

1 . A paper feeding apparatus comprising: 
 a sheet tray that is capable of storing a plurality of sheets and includes, at a front thereof, a separation wall that is struck by an edge the plurality of sheets in a paper feeding direction;    a pickup roller including a drive shaft disposed so as to cross the sheet tray and a plurality of roller parts intermittently attached to the drive shaft;    elastic supporting means for substantially independently supporting a plurality of exposed parts of the drive shaft so as to apply pressure towards a base plate of the sheet tray; and    a driving mechanism that drives the drive shaft of the pickup roller and is disposed on the outer surface side of the sheet tray.    
   
   
       2 . A paper feeding apparatus according to  claim 1 , 
 wherein the driving mechanism drives the drive shaft via a one-way clutch.    
   
   
       3 . A paper feeding apparatus according to  claim 1 , 
 wherein the drive shaft of the pickup roller is a flexible shaft.    
   
   
       4 . A paper feeding apparatus according to  claim 1 , 
 wherein the elastic supporting means supports the drive shaft so as to swing in a direction of the base plate about a support point at some distance above the base plate.    
   
   
       5 . A paper feeding apparatus according to  claim 4 , 
 wherein the elastic supporting means includes a plurality of frames that support the drive shaft so that the drive shaft swings and a plurality of elastic bodies that apply pressure to the plurality of exposed parts of the drive shaft or the plurality of frames towards the base plate.    
   
   
       6 . A paper feeding apparatus according to  claim 4 , 
 wherein the elastic supporting means includes a plurality of plate springs for supporting the plurality of exposed parts of the drive shaft with elastically deform parts extending in the paper feeding direction.    
   
   
       7 . A paper feeding apparatus according to  claim 1 , 
 further comprising connecting parts that connect the elastic supporting means and the plurality of exposed parts of the drive shaft on an opposite side of the base plate with a distance no greater than a diameter of the plurality of roller parts.    
   
   
       8 . A paper feeding apparatus according to  claim 1 , 
 wherein the plurality of roller parts are eccentric or noncircular.    
   
   
       9 . A paper feeding apparatus according to  claim 1 , wherein a channel in which the plurality of roller parts are received is formed in the base plate of the sheet tray so as to face the plurality of roller parts.  
   
   
       10 . A paper feeding apparatus according to  claim 1 , 
 wherein the sheet tray is stackable, and a channel in which roller parts of a sheet tray on a lower level are received is formed in a rear surface of the base plate of the sheet tray so as to face the roller parts.    
   
   
       11 . A paper feeding apparatus according to  claim 1 , 
 wherein convex parts formed so as to widen in the paper feeding direction and/or concave parts formed so as to narrow in the paper feeding direction are formed on the separation wall.    
   
   
       12 . A paper feeding apparatus according to  claim 11 , 
 wherein a plurality of types of sheets of different widths are set in the sheet tray and the convex parts are formed at parts of the separation wall that are struck by ends in a sheet width direction of respective types of sheets.    
   
   
       13 . A paper feeding apparatus according to  claim 11 , 
 wherein the concave parts of the separation wall are formed at positions substantially corresponding in the paper feeding direction to the plurality of roller parts of the pickup roller.    
   
   
       14 . A paper feeding apparatus according to  claim 13 , 
 wherein a plurality of types of sheets of different widths are set in the sheet tray and parts of the separation wall that are struck by ends in a sheet width direction of respective types of sheets are non-concave parts.    
   
   
       15 . A paper feeding apparatus according to  claim 11 , further comprising: 
 a sheet width adjusting plate that moves on a surface of the base plate of the sheet tray to set a plurality of types of sheets of different widths; and    a mask plate that moves together with the sheet width adjusting plate and forms parts for raising ends of the respective types of sheets in a sheet width direction at a surface of the separation wall.    
   
   
       16 . A paper feeding apparatus according to  claim 1 , 
 wherein a first angle between a front end part of the separation wall in the paper feeding direction and the base plate of the sheet tray is smaller than a second angle between a back end part of the separation wall in the paper feeding direction and the base plate of the sheet tray.    
   
   
       17 . A paper feeding apparatus according to  claim 11 , 
 wherein a first angle between front end parts of the convex parts in the paper feeding direction and the base plate of the sheet tray is smaller than a second angle between back end parts of the convex parts in the paper feeding direction and the base plate of the sheet tray.    
   
   
       18 . A paper feeding apparatus according to  claim 3 , 
 wherein the sheet tray supports sheet set in the sheet tray so that at least parts near both ends in a sheet width direction bend in the sheet width direction.    
   
   
       19 . A paper feeding apparatus according to  claim 18 , 
 wherein the sheet tray supports the plurality of sheets set in the sheet tray so that a pickup roller-side of the plurality of sheets are bent in a concave manner.    
   
   
       20 . A paper feeding apparatus according to  claim 18 , 
 further comprising bending parts that are located at side wall sides of the base plate of the sheet tray and support the sheet so that at least parts near both ends bend in the sheet width direction.    
   
   
       21 . A paper feeding apparatus according to  claim 20 , 
 wherein at least one of side walls of the sheet tray moves together with one of the bending parts in the sheet width direction.    
   
   
       22 . A paper feeding apparatus according to  claim 18 , 
 wherein the base plate of the sheet tray is curved and both side walls of the sheet tray symmetrically move about a center in the sheet width direction.    
   
   
       23 . A printing apparatus, comprising: 
 a paper feeding apparatus according to  claim 1;  and    a printing mechanism that prints on a sheet fed from the paper feeding apparatus.    
   
   
       24 . A multiple paper feeding apparatus in which a plurality of paper feeding apparatuses according to  claim 1  are stacked.  
   
   
       25 . A multiple paper feeding apparatus according to  claim 24 , wherein the plurality of paper feeding apparatuses are of equal width.  
   
   
       26 . A multiple paper feeding apparatus according to  claim 24 , 
 wherein respective paper feeding apparatuses include a sheet width adjusting plate that moves on a surface on the base plate of the sheet tray to set various types of sheets with different widths on a same side, out of a left side and a right side, of the respective sheet trays.    
   
   
       27 . A multiple paper feeding apparatus according to  claim 24 , 
 wherein respective paper feeding apparatuses have the driving mechanism disposed on an outer surface on either a left or a right side and paper feeding apparatuses with driving mechanisms disposed on different outer surfaces are alternately stacked.    
   
   
       28 . A printing apparatus, comprising: 
 a multiple paper feeding apparatus according to  claim 24;  and    a printing mechanism that prints on a sheet fed from the multiple paper feeding apparatus.    
   
   
       29 . A paper feeding apparatus comprising: 
 a sheet tray that is capable of storing a plurality of sheets and includes, at a front thereof, a separation wall that is struck by an edge of the plurality of sheets in a paper feeding direction; and    a pickup roller disposed so as to cross the sheet tray,    wherein the edge of the plurality of sheets remaining in the sheet tray strike the separation wall, and a first angle between a front end part of the separation wall in the paper feeding direction and the base plate of the sheet tray is smaller than a second angle between a back end part of the separation wall in the paper feeding direction and the base plate of the sheet tray.    
   
   
       30 . A printing apparatus, comprising: 
 a paper feeding apparatus according to  claim 29;  and    a printing mechanism that prints on a sheet fed from the paper feeding apparatus.    
   
   
       31 . A paper feeding apparatus comprising: 
 a sheet tray that is capable of storing a plurality of sheets and includes, at a front thereof, a separation wall that is struck by an edge of the plurality of sheets in a paper feeding direction; and    a pickup roller disposed so as to extend along the separation wall,    wherein convex parts formed so as to widen in the paper feeding direction and/or concave parts formed so as to narrow in the paper feeding direction are formed on the separation wall.    
   
   
       32 . A paper feeding apparatus according to  claim 31 , 
 wherein the pickup roller includes a drive shaft disposed so as to cross the sheet tray and a plurality of roller parts intermittently attached to the drive shaft and the concave parts of the separation wall are formed at positions substantially corresponding in the paper feeding direction to the roller parts of the pickup roller.    
   
   
       33 . A paper feeding apparatus according to  claim 31 , 
 wherein a first angle between front end parts of the convex parts in the paper feeding direction and the base plate of the sheet tray is smaller than a second angle between back end parts of the convex parts in the paper feeding direction and the base plate of the sheet tray.    
   
   
       34 . A printing apparatus, comprising: 
 a paper feeding apparatus according to  claim 31;  and    a printing mechanism that prints on a sheet fed from the paper feeding apparatus.    
   
   
       35 . A paper feeding apparatus comprising: 
 a sheet tray that is capable of storing a plurality of sheets and supports the plurality of sheets set in the sheet tray so that it least parts near both ends in a sheet width direction bend in the sheet width direction; and    a flexible pickup roller, intermittent parts thereof are independently pressurized by a plurality of springs, disposed so as to cross the sheet tray.    
   
   
       36 . A paper feeding apparatus comprising: 
 a sheet tray that is capable of storing a plurality of sheets and supports sheet set in the sheet tray so that at least parts near both ends in a sheet width direction bend in the sheet width direction:    a flexible pickup roller disposed so as to cross the sheet tray: and    bending parts that are located at side wall sides of a base plate of the sheet tray and support the plurality of sheets set in the sheet tray so that at least parts near both ends bend in the sheet width direction.    
   
   
       37 . A paper feeding apparatus according to  claim 35 , wherein a base plate of the sheet tray is curved.  
   
   
       38 . A printing apparatus, comprising: 
 a paper feeding apparatus according to  claim 35;  and    a printing mechanism that prints on a sheet fed from the paper feeding apparatus.    
   
   
       39 . A printing apparatus, comprising: 
 a paper feeding apparatus according to  claim 36;  and    a printing mechanism that prints on a sheet fed from the paper feeding apparatus.    
   
   
       40 . A paper feeding apparatus according to  claim 1 , wherein 
 the driving shaft is a metal stranded wire.    
   
   
       41 . A paper feeding apparatus according to  claim 35 , wherein the flexible pickup roller includes a driving shaft made of a metal stranded wire.