Automatic paper feed device, image reading apparatus, and image forming apparatus

Abstract

An automatic paper feed device is provided, including a cover member that has a paper insertion opening in a nearly rectangular shape, the paper insertion opening having a longitudinal direction perpendicular to both a transport direction of the paper and a thickness direction of the paper. The paper insertion opening includes a first end opening portion, a second end opening portion, and a center opening portion arranged in the longitudinal direction of the paper insertion opening. The paper insertion opening connects a placement unit, in which paper is placed, with a separation and transport mechanism, that separates paper placed in the placement unit and transports paper placed in the placement unit in the transport direction. The first and second end opening portions are each larger in size than the central opening portion.

1 . An automatic paper feed device comprising:
 a placement unit in which paper is placed;   a separation unit which is configured to separate paper placed in the placement unit; and   a paper insertion opening in a nearly rectangular shape, the paper insertion opening being elongated in a direction perpendicular to both a transport direction of the paper and a thickness direction of the paper, the paper insertion opening also being configured to communicate the placement unit to the separation unit;   the paper insertion opening comprising:
 a first end opening portion which is positioned at one end portion in a longitudinal direction of the paper insertion opening; 
 a second end opening portion which is positioned at the other end portion in the longitudinal direction of the paper insertion opening; and 
 a center opening portion which is positioned between the first end opening portion and the second end opening portion; 
   wherein the first and second end opening portions are each larger in size than the center opening portion, such that a thickness dimension, parallel to the thickness direction of the paper, of each of the first and second end opening portions is greater than a thickness dimension of the center opening portion.   
     
     
         2 . The automatic paper feed device according to  claim 1 ;
 wherein the first end opening portion includes a first end joint portion which connects with a first central joint portion of the center opening portion at a first opening connection point;   wherein a dimension of the paper insertion opening parallel to the thickness direction of the paper increases smoothly and gradually from the first central joint portion to the first end joint portion, such that dimensions parallel to the thickness direction of the paper of the first end joint portion and the first central joint portion at the first opening connection point are equal to each other;   wherein the second end opening portion includes a second end joint portion which connects with a second central joint portion of the center opening portion at a second opening connection point; and   wherein the dimension of the paper insertion opening parallel to the thickness direction of the paper increases smoothly and gradually from the second central joint portion to the second end joint portion, such that dimensions parallel to the thickness direction of the paper of the second end joint portion and the second central joint portion at the second opening connection point are equal to each other.   
     
     
         3 . The automatic paper feed device according to  claim 1 ;
 wherein the top of the center opening portion extends in the direction opposite, and parallel, to the transport direction of the paper, relative to the tops of the first and second end opening portions.   
     
     
         4 . The automatic paper feed device according to  claim 1 ;
 wherein a size of the center opening portion and a size of the first end opening portion change smoothly from the center opening portion to the first end opening portions; and   wherein the size of the center opening portion and a size of the second end opening portion change smoothly from the center opening portion to the second end opening portions.   
     
     
         5 . The automatic paper feed device according to  claim 1 ;
 wherein a pair of paper guides are provided in the paper placement unit, the pair of paper guides being movable in the longitudinal direction of the paper insertion opening,   wherein the pair of paper guides contacts sides of the paper parallel to the transport direction and guides the transport of the paper;   wherein at least a part of the first end opening portion exists in a location corresponding to a position between the pair of paper guides, even when the distance between the pair of paper guides is at its smallest; and   wherein at least a part of the second end opening portion exists in a location corresponding to a position between the pair of paper guides, even when the distance between the pair of paper guides is at its smallest.   
     
     
         6 . The automatic paper feed device according to  claim 1 ;
 wherein the paper insertion opening is symmetric with respect to a nearly central part of the paper insertion opening in the longitudinal direction of the paper insertion opening.   
     
     
         7 . The automatic paper feed device according to  claim 1 ;
 wherein the automatic paper feed device is provided in an image reading apparatus, having an image pick-up device that (1) generates an electrical signal based on received light and (2) reads an image contained in an original;   the image reading apparatus comprising:
 a reading window for image reading. 
   
     
     
         8 . The automatic paper feed device according to  claim 1 ;
 wherein the automatic paper feed device is provided in an image forming apparatus;   the image forming apparatus comprising:
 an image forming unit that forms an image on paper. 
   
     
     
         9 . An automatic paper feed device comprising:
 a placement unit in which paper is placed;   a transport mechanism which transports the paper in a transport direction from outside the automatic paper feed device to inside the automatic paper feed device; and   a paper insertion opening located in an opening plane, the opening plane marking a location at which an edge of the paper intersecting the transport direction passes from outside the automatic paper feed device to inside the automatic paper feed device, the paper insertion opening having a longitudinal direction perpendicular to both the transport direction of the paper and a thickness direction of the paper, the thickness direction of the paper being perpendicular to a plane of the paper which is parallel to the transport direction;   the paper insertion opening comprising:
 a first end opening portion; 
 a second end opening portion; and 
 a center opening portion; 
 wherein the first end opening portion is disposed on one side of the center opening portion in the longitudinal direction and the second end opening portion is disposed on the other side of the center opening portion in the longitudinal direction; 
 wherein the first end opening portion is larger in size than the center opening portion, such that a thickness dimension, parallel to the thickness direction of the paper, of the first end opening portion is greater than a thickness dimension of the center opening portion; and 
 wherein the second end opening portion is larger in size than the center opening portion, such that a thickness dimension, parallel to the thickness direction of the paper, of the second end opening portion is greater than the thickness dimension of the center opening portion. 
   
     
     
         10 . The automatic paper feed device according to  claim 9 ;
 wherein the top of the center opening portion extends in the direction opposite, and parallel, to the transport direction of the paper, relative to the tops of the first and second end opening portions.