Medium feeding apparatus, medium feeding method, and non-transitory recording medium

Abstract

A medium feeding apparatus includes a media tray, a feed roller to sequentially feed a plurality of media placed on the media tray, a separation roller located facing the feed roller, and circuitry. The circuitry detects a leading end position of each of a plurality of media in a nip between the feed roller and the separation roller, determines a distance between a leading end position of a preceding medium, which is of the plurality of media in the nip, and a leading end position of a medium following the preceding medium, and sets a characteristic value of the separation roller based on the distance.

1 . A medium feeding apparatus, comprising:
 a media tray;   a feed roller to sequentially feed a plurality of media placed on the media tray;   a separation roller located facing the feed roller; and   circuitry configured to:
 detect a leading end position of each of a plurality of media in a nip between the feed roller and the separation roller; 
 determine a distance between a leading end position of a preceding medium, which is one of the plurality of media in the nip, and a leading end position of a medium following the preceding medium; and 
 set a characteristic value of the separation roller based on the distance. 
   
     
     
         2 . The medium feeding apparatus according to  claim 1 , wherein
 the characteristic value is a torque value,   the separation roller is set to rotate in the same direction as the feed roller when a torque equal to or greater than the torque value is applied to the separation roller, and   the circuitry sets the torque value to a first torque value when the distance is equal to or greater than a threshold value, and sets the torque value to a second torque value greater than the first torque value when the distance is less than the threshold value.   
     
     
         3 . The medium feeding apparatus according to  claim 2 , wherein the circuitry sets the torque value to a third torque value, which is greater than the first torque value and less than the second torque value, when the detected leading end position of the preceding medium is downstream from a predetermined position in the nip in a medium conveying direction and the distance is equal to or greater than the threshold value. 
     
     
         4 . The medium feeding apparatus according to  claim 2 , wherein the circuitry sets the torque value to the second torque value or a fourth torque value greater than the second torque value when the detected leading end position of the preceding medium is downstream from the predetermined position in the nip in the medium conveying direction and the distance is less than the threshold value. 
     
     
         5 . The medium feeding apparatus according to  claim 1 , further comprising a pressing device to press the separation roller toward the feed roller,
 wherein the characteristic value is a pressing force with which the pressing device presses the separation roller toward the feed roller, and   the circuitry sets the pressing force to a first pressing force when the distance is equal to or greater than a threshold value, and sets the pressing force to a second pressing force less than the first pressing force when the distance is less than the threshold value.   
     
     
         6 . The medium feeding apparatus according to  claim 1 , wherein the circuitry detects the leading end position immediately before the feed roller starts to rotate. 
     
     
         7 . The medium feeding apparatus according to  claim 1 , further comprising an imager to image the leading end position of the medium in an area overlapping the nip when viewed from a direction perpendicular to a medium conveying direction and generate an input image,
 wherein the circuitry detects the leading end position of the medium in the nip based on the input image.   
     
     
         8 . The medium feeding apparatus according to  claim 7 , wherein the imager is located downstream from the nip in the medium conveying direction. 
     
     
         9 . The medium feeding apparatus according to  claim 8 , further comprising a light emitter that is located upstream from the nip in the medium conveying direction and irradiates the area overlapping the nip when viewed from the direction perpendicular to the medium conveying direction. 
     
     
         10 . The medium feeding apparatus according to  claim 9 , further comprising a second light emitter that is located upstream from the nip in the medium conveying direction and irradiates the area overlapping the nip when viewed from the direction perpendicular to the medium conveying direction from a direction different from the light emitter. 
     
     
         11 . A medium feeding method, comprising:
 sequentially feeding a plurality of media placed on a media tray by a feed roller;   detecting a leading end position of each of a plurality of media in a nip between the feed roller and a separation roller located facing the feed roller;   determining a distance between a leading end position of a preceding medium, which is one of the plurality of media in the nip, and a leading end position of a medium following the preceding medium; and   setting a characteristic value based on the distance.   
     
     
         12 . A non-transitory recording medium storing a plurality of instructions which, when executed by one or more processors of a medium feeding apparatus, causes the one or more processors to perform a method, the method comprising:
 sequentially feeding a plurality of media placed on a media tray by a feed roller;   detecting a leading end position of each of a plurality of media in a nip between the feed roller and a separation roller located facing the feed roller;   determining a distance between a leading end position of a preceding medium, which is one of the plurality of media in the nip, and a leading end position of a medium following the preceding medium; and   setting a characteristic value of the separation roller based on the distance.