Sheet feeding apparatus

Abstract

A sheet feeding apparatus includes a sheet loading tray configured to be loaded with a sheet, an intake unit configured to take in the sheet loaded in the sheet loading tray to an apparatus body, a feeding unit configured to feed the sheet taken in by the intake unit, a separation unit configured to contact the feeding unit and separate a sheet to be fed from a plurality of sheets, and a sheet detection unit configured to emit light and detect presence or absence of a sheet between the feeding unit and the separation unit.

What is claimed is: 
     
         1 . A sheet feeding apparatus comprising:
 a sheet loading tray configured to be loaded with a sheet;   an intake unit configured to take in the sheet loaded in the sheet loading tray to an apparatus body;   a feeding unit configured to feed the sheet taken in by the intake unit;   a separation unit configured to contact the feeding unit and separate a sheet to be fed from a plurality of sheets; and   a sheet detection unit configured to emit light and detect presence or absence of a sheet between the feeding unit and the separation unit.   
     
     
         2 . The sheet feeding apparatus according to  claim 1 ,
 wherein the feeding unit includes a first feed roller part and a second feed roller part that have a rotation axis extending in a sheet width direction,   the separation unit includes a first separation roller part and a second separation roller part having a rotation axis extending in the sheet width direction, and   the sheet detection unit is provided such that the light passes at least between the first feed roller part and the second feed roller part.   
     
     
         3 . The sheet feeding apparatus according to  claim 2 ,
 wherein the first feed roller part and the first separation roller part are configured to contact to each other to form a first nip range,   the second feed roller part and the second separation roller part are configured to contact each other to form a second nip range, and   a range over which the sheet detection unit detects presence or absence of the sheet is within a range of the first nip range and the second nip range in a conveyance direction of the sheet and between the first nip range and the second nip range in a sheet width direction.   
     
     
         4 . The sheet feeding apparatus according to  claim 3 ,
 wherein the sheet detection unit includes a light emitting unit and a light receiving unit, and   the light emitted by the light emitting unit is obliquely incident on a surface of a sheet present in the first nip range and the second nip range.   
     
     
         5 . The sheet feeding apparatus according to  claim 2 ,
 wherein the sheet detection unit is provided such that the light passes between the first separation roller part and the second separation roller part and between the first feed roller part and the second feed roller part.   
     
     
         6 . The sheet feeding apparatus according to  claim 1 , further comprising:
 a moving unit configured to move the intake unit between an intake position in contact with the sheet loaded in the sheet loading tray and a retracted position away from the sheet; and   a control unit configured to control the feeding unit and the moving unit,   wherein, in a case where a sheet is detected by the sheet detection unit when starting sheet feeding by the feeding unit, the control unit controls the moving unit such that the intake unit maintains the retracted position.   
     
     
         7 . The sheet feeding apparatus according to  claim 6 ,
 wherein, in a case where a sheet is not detected by the sheet detection unit when starting sheet feeding by the feeding unit, the control unit controls the moving unit such that the intake unit moves to the intake position.   
     
     
         8 . The sheet feeding apparatus according to  claim 3 ,
 wherein the sheet detection unit includes a light emitting unit and a light receiving unit, and   the light emitted by the light emitting unit is perpendicularly incident on a surface of a sheet present in the first nip range and the second nip range.   
     
     
         9 . The sheet feeding apparatus according to  claim 4 , further comprising:
 a light guide configured to change a direction of the light emitted from the light emitting unit.   
     
     
         10 . The sheet feeding apparatus according to  claim 4 ,
 wherein the sheet detection unit includes a reflective photoelectric sensor, and   the light emitting unit and the light receiving unit are located downstream of a rotation center of the feeding unit in the conveyance direction of the sheet.   
     
     
         11 . The sheet feeding apparatus according to  claim 9 ,
 wherein the light receiving unit is located downstream of a rotation center of the feeding unit in the conveyance direction of the sheet, and   the light emitting unit and the light guide are located upstream of a rotation center of the separation unit in the conveyance direction of the sheet.   
     
     
         12 . The sheet feeding apparatus according to  claim 11 ,
 wherein the light guide includes a first end portion that receives the light emitted from the light emitting unit, and a second end portion that is different from the first end portion and discharges the light, and   the light guide has a curved shape such that the second end portion is oriented toward the light receiving unit.   
     
     
         13 . The sheet feeding apparatus according to  claim 12 ,
 wherein the second end portion is located between a rotation center of the separation unit and an upper end portion of the separation unit.   
     
     
         14 . The sheet feeding apparatus according to  claim 12 , further comprising:
 a holding unit configured to cover the separation unit, such that the separation unit is partially exposed in a conveyance path of the sheet,   wherein the holding unit includes a first holding part and a second holding part configured to be attached to and detached from the first holding part and to hold the light guide.   
     
     
         15 . The sheet feeding apparatus according to  claim 12 ,
 wherein a shaft portion of the light guide is inclined from an upstream side in the conveyance direction of the sheet to a downstream side in the conveyance direction of the sheet.