Document reading apparatus

Abstract

A document reading apparatus includes a table on which a document is set, a sensor which includes a light receiving plane for receiving an image of the document set on the table, and a lens disposed between the table and the light receiving plane which forms an image of the document on the light receiving plane of the sensor. A first extended line of the table extends from the table in a plane of the table, a second extended line of the light receiving plane extends in a plane of the light receiving plane, and a third extended line of the lens which extends in a direction perpendicular to an optical axis of the lens extend so as to intersect at one point.

What is claimed is:  
     
         1 . A document reading apparatus, comprising: 
 a table on which a document is set;    a sensor which comprises a light receiving plane for receiving an image of the document set on the table; and    a lens disposed between the table and the light receiving plane which forms an image of the document on the light receiving plane;    wherein a first extended line of the table extends from the table in a plane of the table, a second extended line of the light receiving plane extends in a plane of the light receiving plane, and a third extended line of the lens extends in a direction perpendicular to an optical axis of the lens, and the first, second and third extended lines extend so as to intersect at one point.    
     
     
         2 . The document reading apparatus according to  claim 1 , wherein the document has a rectangular form, and the arrangement of the document on the table together with the lens and light receiving plan form a trapezoidal image of the document on the light receiving plane.  
     
     
         3 . The document reading apparatus according to  claim 2 , further comprising a controller which changes the trapezoidal image of the document so as to form a rectangular image thereof.  
     
     
         4 . The document reading apparatus according to  claim 1 , wherein the sensor and the lens are disposed at a position offset with respect to the document.  
     
     
         5 . The document reading apparatus for reading a document, comprising: 
 a pedestal on which the document to be read is set at a position with respect to the pedestal;    a line sensor which moves in a sub-scan direction and scans an image of the document optically;    a reading head having the line sensor incorporated therein; and    a supporting leg which extends from the pedestal and supports the reading head above the pedestal;    wherein the line sensor is disposed in the reading head at a position in which a first line extending in the sub-scan direction and a second line which extends in a plane of the pedestal intersect.    
     
     
         6 . The document reading apparatus according to  claim 5 , further comprising a lens which forms the image of the document on the line sensor, the lens being disposed at a position so that an optical axis of the lens and the first line extending in the sub-scan direction intersect without being perpendicular to one another.  
     
     
         7 . The document reading apparatus according to  claim 6 , wherein the first line and the optical axis of the lens intersect at an acute angle.  
     
     
         8 . The document reading apparatus according to  claim 5 , wherein the reading head further comprises: 
 a bearing portion for supporting the line sensor;    a rail for guiding a movement of the bearing portion; and    a motor for driving the line sensor supported by the bearing portion along the rail.    
     
     
         9 . The document reading apparatus according to  claim 5 , wherein the supporting leg is disposed on an edge portion of the pedestal.  
     
     
         10 . The document reading apparatus according to  claim 5 , wherein the supporting leg is disposed on an edge portion of the pedestal.  
     
     
         11 . The document reading apparatus according to  claim 5 , wherein the document is set on the pedestal.  
     
     
         12 . A document reading apparatus, comprising: 
 a pedestal on which a document is set; and    a head comprising an image sensor having a light receiving plane and which reads an image of the document, and a lens having an optical axis and which forms the image of the document on the light receiving plane of the image sensor;    wherein the head has the image sensor and the lens disposed therein with the lens being maintained at a fixed position during reading of the document so that an optical axis of the lens is offset with respect to a center of the document.    
     
     
         13 . The document reading apparatus according to  claim 12 , wherein the head is disposed at a position which does not interfere with setting of the document on the pedestal and the lens is disposed at a position offset with respect to edges of the document.  
     
     
         14 . The document reading apparatus according to  claim 12 , wherein the image of the document formed on a light receiving face of the image sensor is inverted horizontally and vertically with respect to the document.  
     
     
         15 . An document reading apparatus, comprising: 
 a sensor which reads an image of a document, the sensor being disposed at a position deviated from a center of the document so that a distorted image of the document is formed on the sensor; and    a controller which changes the distorted image read by the sensor into an image corresponding to the document.    
     
     
         16 . The document reading apparatus according to  claim 15 , wherein the document is rectangular and the distorted image is a trapezoidal image.  
     
     
         17 . The document reading apparatus according to  claim 15 , wherein the sensor lies in a main scan direction, and the controller controls a motion of the sensor in a sub-scan direction which lies at a right angle to a main scan direction.  
     
     
         18 . The document reading apparatus according to  claim 15 , further comprising: 
 a table on which the document is set; and    a lens which forms the image of the document on the sensor;    wherein a first extended line of the sensor, a second extended line of the table, and a third extended line of the lens intersect at one point.    
     
     
         19 . The document reading apparatus according to  claim 15 , wherein the sensor comprises one of a one-dimensional image sensor and a two-dimensional image sensor.  
     
     
         20 . The document reading apparatus according to  claim 15 , further comprising a motor which drives the sensor in a sub-scan direction, and wherein the sensor is disposed in an arrangement where an extended line of the sub-scan direction and an extended line of a plane of the document intersect.  
     
     
         21 . An image reading apparatus comprising: 
 a table having a setting plane on which a document is set;    a leg which stands on the table;    a head section positioned on the leg; and    a line sensor incorporated in the head and aligned in a first direction which is parallel with the setting plane, the line sensor being movable in a second direction which intersects the setting plane while the sensor reads an image of the document.    
     
     
         22 . The image reading apparatus according to  claim 21 , further comprising a lens which forms the image of a document and having an extended line which intersects a first extended line of the table and a second extended line of the second direction at one point.  
     
     
         23 . The document reading apparatus according to  claim 21 , further comprising a lens which forms the image of the document on the line sensor, the lens being disposed at a position in which a lens optical axis of the lens and a plane formed by moving of the line sensor in a sub-scan direction intersect in an acute angle.  
     
     
         24 . The document reading apparatus according to  claim 21 , wherein the head further comprises: 
 a bearing portion for supporting the line sensor;    a rail for guiding a movement of the bearing portion; and    a motor for driving the line sensor supported by the bearing portion along the rail.    
     
     
         25 . The document reading apparatus according to  claim 21 , wherein the supporting leg is disposed on an edge portion of the pedestal.