Abstract:
An automatic document feeding apparatus comprises a document rest for allowing a document to be placed thereon, a conveying belt for conveying the document onto the document rest, an urging roller for urging the conveying belt toward the document rest, a retaining member for retaining the urging roller, a support member for supporting the retaining members in a way to be slidable in a direction intersecting with the conveying direction of the document, a projection provided at one end of the retaining member, a slider mounted on the support member to slide along a conveying direction of the document, an oblique guide hole formed in the slider in a way to be made oblique with respect to the slide direction and slidably inserting the projection of the retaining member therein, and moving means which, by causing the slider to slide in the conveying direction of the document, moves the projection of the retaining member along the oblique guide hole to allow the urging roller to move in a direction intersecting with the conveying direction of the document.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an automatic document feeding apparatus for automatically feeding a document used for, for example, an electrophotographic type copier to a document glass. 
     As this type of automatic document feeding apparatus, a type is known by which a document is fed to a document glass by the running of a conveying belt. In this automatic document feeding apparatus, in order to impart an enhanced conveying capability to the document, the conveying belt is urged by urging rollers from its inner side toward the document glass. 
     In the conventional apparatus, since the urging roller is fixedly arranged at all times in a predetermined position, a band-like contact mark is formed at the same area on the conveying belt in a manner to correspond to a width dimension of the urging roller. And the dirty spot, wear, etc., are locally concentrated on the conveying belt at that place. 
     This necessitates the cleaning of the cleaning belt or frequent exchange of conveying belts. And more time and labor and more cost are required in these operations, thus posing a problem. 
    
    
     BRFIEF SUMMARY OF THE INVENTION 
     It is accordingly the object of the present invention to provide an automatic document feeding apparatus which can urge a conveying belt by urging rollers without locally concentrating a smudge, wear, etc., on the conveying belt. 
     An automatic document feeding apparatus of the present invention comprises a document rest for allowing a document to be placed thereon, a conveying belt for conveying the document onto the document rest, urging rollers for urging the conveying belt toward the document rest, and moving means for moving the urging roller in a direction intersecting with the document conveying direction. 
     An automatic document feeding apparatus of the present invention comprises a document rest for allowing a document to be placed thereon, a conveying belt for conveying the document onto the document rest, urging rollers for urging the conveying belt toward the document rest, a retaining member for retaining the urging roller, a supporting member for supporting the retaining member in a way to be slidable in a direction intersecting with the conveying direction of the document, and moving means for moving the retaining member to allow the urging roller to be moved. 
     An automatic document feeding apparatus of the present invention comprises a document rest for allowing a document to be placed thereon, a conveying belt for conveying the document onto the document rest, an urging roller for urging the conveying belt toward the document rest, a retaining member for retaining the urging roller, a support member for supporting the retaining member in a way to be slidable in a direction intersecting with the conveying direction of the document, a projection provided at one end of the retaining member, a slider mounted on the support member to slide along the conveying direction of the document, an oblique guide hole formed in the slider in a way to be made oblique with respect to the slide direction and slidably inserting the projection of the retaining member therein, and moving means which, by causing the slider to slide in the conveying direction of the document, moves the projection of the retaining member along the oblique guide hole to allow the urging member to be moved in a direction intersecting with the conveying direction of the document. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a front view showing an electrophotographic type copier equipped with an automatic document feeding apparatus according to a first embodiment of the present invention; 
     FIG. 2 is an exploded perspective view showing a moving mechanism of urging rollers for urging a conveying belt; 
     FIG. 3 is a perspective view showing a drive system of the conveying belt; 
     FIG. 4 is a perspective view showing a practical form of a slider of the first embodiment; 
     FIG. 5 is a plan view showing a moving state of urging rollers; 
     FIG. 6 is a perspective view showing a second practical form of a slider of a second embodiment; 
     FIG. 7 is a plan view showing a moving state of urging rollers; 
     FIG. 8 is a perspective view showing a third practical form of a slider of a third embodiment; and 
     FIG. 9 is a plan view showing a moving state of urging rollers. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiments of the present invention will be explained below with reference to the accompanying drawing. 
     FIG. 1 shows an electrophotographic copier. Reference numeral  1  in FIG. 1 shows a body of the copier. At the upper surface section of the body  1  a document glass  2  is provided as a document rest. 
     An automatic document feeding apparatus  3  is provided on a document glass  2  to automatically feed a document sheet onto the document glass  2 . The automatic document feeding apparatus  3  includes a document sheet supply rest  5  on which document sheets are set. The document sheet set on the document sheet supply rest  5  is picked up by a pick-up roller  6  and conveyed along a supplying system conveying path  7 . At the supplying system conveying path  7 , a sheet supply roller  8  for supplying the document sheets one by one and aligning rollers for arraying the supplied document sheet are arranged sequentially along the conveying direction of the document. 
     The automatic document feeding apparatus  3  includes a conveying belt  10  for allowing the document sheet which is arrayed by the aligning roller  9  to be conveyed along the document glass  2  and a discharging system conveying path  11  for allowing the document sheet which is conveyed from the conveying belt  10  to be discharged. 
     That portion of the conveying belt  10  facing the document glass  10  is urged by urging rollers  16 a to  16   c  from its inner side toward the document glass. The conveying belt  10  is trained between a drive roller  17  and a driven roller  18 . The urging rollers  16   a , . . . ,  16   c  are arranged, as a plurality of rollers, at predetermined intervals over the feeding direction of the document. 
     A discharge sensor  12  for detecting the document sheet and sheet discharge roller  13  for discharging the document sheet are arranged in the discharge system conveying path  11 . A document discharge section  14  is provided at the upper surface section of the automatic document feeding apparatus  3  to receive the document sheet discharged from the sheet discharge roller  13 . 
     FIG. 2 is a perspective, exploded view showing a moving mechanism  19  of the urging rollers  16   a , . . . ,  16   c.    
     A drive motor  26  (shown in FIG. 3) is connected to a drive roller shaft  17   a  of the conveying belt  10  through a gear train  24  comprising first to fourth gears  20  to  23  and clutch  25 . A shaft  32  of the aligning roller  9  is connected to the fourth gear  23  through a fifth gear  28 , timing belt  29  and sixth gear  30 . A shaft  37  of the sheet discharge roller  13  is connected to a driven roller shaft  18   a  of the conveying belt  10  through seventh to ninth gears  33  to  35 . 
     A pinion  39  and clutch  40  are connected to the driven roller shaft  18   a  of the conveying belt  10 . A rack section  42  is provided on one end portion of a slider  41  and is in mesh with the pinion  39 . Elongated holes  43  are provided one at each end portion of the slider  41  along a longitudinal direction of the slider. A plurality of (three) oblique guide holes  44   a , . . . ,  44   c  are provided between these elongated holes  43  and  43  such that these guide holes  44   a  to  44   c  are obliquely formed relative to the longitudinal direction (moving direction) of the slider  41 . 
     The pushing rollers  16   a , . . . ,  16   c  are retained in two units on a retaining member  47  in a direction perpendicular to the document conveying direction. The retaining member  47  is so supported on a support member  48  as to be slidable in a direction perpendicular to the document conveying direction. 
     The urging rollers  16   a  (. . . ,  16   c ) is retained by urging springs  50  on the retaining member  47 . Elongated holes  51 ,  51  are provided one at each end portion of the retaining member  48 . And stepped screws  53 ,  53  are inserted into the elongated holes  51 ,  51  and the threaded into the end portions of the support member  48 . That is, the retaining member  47  is so mounted on the support member  48  as to be slidable along its longitudinal direction. 
     A projection member  55  is provided on one end of the retaining member  1  and inserted into the oblique guide hole  44   a  (. . . ,  44   c ) of the slider  41  through an elongated hole  56  in one end portion of the support member  48 . 
     The above-mentioned slider  41  is slidably coupled between one-end side portions of the support members  48 ,  48 . That is, the slider  41  is slidably and detachably mounted by threadably inserting stepped screws  57 ,  57  from below the elongated holes  43 ,  43  into screw holes  58 ,  58  of the support members  48 ,  48 . 
     A sensor  59  is provided in the other end direction of the slider  41  to detect the position of the slider  41 . 
     FIG. 3 is a perspective view showing a drive system of a document supply section. 
     Reference numeral  61  in FIG. 3 shows a drive motor. Gears  64 ,  65  are coupled to a drive gear  62  of the drive motor  61  through a drive belt  63 . A shaft  58  of the pick-up roller  6  is connected to a gear  64  through gears  66 ,  67 , a shaft  70  of the sheet supply roller  8  is connected to the gear  66  through the gear  69 , and a shaft  71  of the aligning roller  9  is connected to the gear  65 . 
     The automatic document feeding operation will be explained below. 
     With the drive motor  61  rotated, the gears  64 ,  65  are rotated through the drive belt  63 . With the rotation of the gear  64 , the pick-up roller  6  is rotated through the gear  67  and shaft  68  and the sheet supply roller  8  is rotated through the gear  69  and shaft  70 . With the rotation of the gear  65 , the aligning roller  9  is rotated through the shaft  71 . 
     With the rotation of the pick-up roller  6 , the document sheet on the document sheet rest  5  is picked up. In this case, the document sheets are supplied one by one through the rotation of the sheet supply roller  8  and, with the rotation of the aligning roller  9 , the document sheet is arrayed and sent out onto the conveying belt  10 . 
     Further, with the rotation of the aligning roller  9 , the drive roller shaft  17   a  of the conveying belt  10  is rotated through the gear  30 , timing belt  29 , gear  28 , gear  23 , gear  22 , gear  21  and gear  20  and the conveying belt  10  is run. The conveying belt  10  is urged by the urging rollers  16   a , . . . ,  16   c  from its inner side and, while pushing the document sheet toward the document glass  21 , conveys the document sheet and feeds the document sheet onto the document glass  2 . When the document sheet is sent to a predetermined position, the clutch  25  is released and a power transmission is stopped and the document sheet is stopped. The stopped document has its image information read out by an optical system not shown. After the image information is read out from the document sheet, the clutch  25  is coupled and again the conveying belt  10  is run to allow the document sheet to be sent out and discharged through the sheet discharge roller  13  to the sheet discharge section  14 . 
     Incidentally, the positions of the above-mentioned urging rollers  16   a , . . . ,  16   c  are periodically changed to prevent the conveying belt  10  being soiled and worn. 
     Then the operation of moving the urging rollers  16   a , . . . ,  16   c  will be explained below. 
     When the clutch  40  is coupled with the conveying belt  10  in a running state, a rotation force of a driven roller shaft  18   a  of the conveying belt  10  is transmitted to the pinion  39  and the pinions  39  is rotated. By this rotation, the slider  41  is moved n the conveying direction of the document through the rack section  42 . By this movement, the projection member  55  of the retaining member  47  is guided in the oblique guide hole  44   a  (. . . ,  44   c ) to allow the retaining member  47  to be moved in a direction perpendicular to the conveying direction of the document sheet. And the urging-roller  16   a  (. . . ,  16   c ) is moved in the same direction. By the movement of this urging roller  16   a  (. . . ,  16   c ), the position of the contacting of the urging roller  16   a  ( 16   c ) with the conveying belt  10  is made variable as shown, for example, in FIG.  5 . 
     When the slider  41  is moved by a predetermined amount, the sensor  59  detects it. Upon this detection, the clutch  40  is released and the retaining member  47  stops its movement and the movement of the urging roller  16   a  (. . . ,  16   c ) is stopped. 
     As a condition under which the urging roller  16  (. . . ,  16   c ) is moved, for example, an initializing operation is done each time the number of document sheets sent reaches a predetermined sheet number and, by doing so, the movement is started. 
     That is, whether or not the slider  41  is detected by the sensor  25  is acknowledged. If it is detected, the slider  41  is moved. 
     If it is not detected, the conveying belt  10  is reverse-rotated and the clutch  40  is coupled and the slider  41  is moved until the sensor  25  detects the slider  41 . 
     According to the present embodiment, since the urging rollers  16   a , . . . ,  16   c  of the conveying belt  10  are moved in the direction perpendicular to the conveying direction of the document, it is possible to change the urging position of the conveying belt  10  by the urging rollers  16   a , . . . ,  16   c . As a result, it is possible to alleviate the wear and soiling of the conveying belt  10  and extend the life of the conveying belt. 
     FIG. 6 shows a second embodiment of the slider. 
     Although, in the above-mentioned embodiment, the guide holes  44   a , . . . ,  44   c  are formed in the slider  41  in the same oblique direction, the second embodiment is such that, out of three guide holes  44   a , . . . ,  44   c , the middle guide hole  44   b  are formed in a “back-slash” direction relative to the other oblique guide holes  44   a  and  44   c.    
     According to this embodiment, at a time of moving the slider  41 , the moving direction of the middle urging roller  16   b  is reverse to those of the remaining oblique rollers  16   a ,  16   c  and it is possible to shift the contacting position of the middle urging roller relative to the conveying belt  10 . 
     FIG. 8 shows a third embodiment of the slider. 
     In this embodiment, out of three oblique guide holes  44   a , . . . ,  44   c , the leftmost oblique guide hole  44   a  is formed in a “back-slash” direction relative to the other oblique guide holes  44   b ,  44   c.    
     According to this third embodiment, at a time of moving the slider  41 , as shown in FIG. 9, the moving direction of a leftmost urging roller  16   a  is reverse to those of the other urging rollers  16   b ,  16   c  and it is possible to shift the contacting position of that urging roller relative to the conveying belt  10  in a reverse direction. 
     That is, the moving amount and moving direction of the urging roller  16  are determined by the oblique angles and oblique directions of the oblique guide holes  44   a , . . . ,  44   c.    
     Further, the slider is detachably mounted on the support members  48 ,  48  and it is possible to change a slider having oblique guide holes of desired oblique angles and oblique directions. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.