Patent Publication Number: US-8542415-B2

Title: Image processing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2009-088247, which was filed on Mar. 31, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image processing apparatus that reads an image recorded on both front and back surfaces of a sheet conveyed by a plurality of rollers. 
     2. Description of the Related Art 
     Conventionally, an image processing apparatus comprising a U-turn conveying path and two image reading portions is known. In such an image processing apparatus, an image of one of the front and back surfaces of the sheet is read by one image reading portion first, and after the front and back surfaces of the sheet is reversed, an image of another of the front and back surfaces of the sheet is read by another image reading portion. 
     SUMMARY OF THE INVENTION 
     In such an image processing apparatus comprising such a U-turn conveying path, a plurality of rotary shafts are disposed in the U-turn conveying path, a conveying roller is mounted on each of the rotary shafts, and each of the conveying rollers is paired with a pinch roller. When the sheet is nipped and conveyed by the conveying rollers and the pinch rollers, a jamming of the sheet may occur. 
     A need has arisen to provide an image processing apparatus that a jamming prevention operation can be easily carried out while being compact. 
     In an embodiment of the invention, an image processing apparatus capable of reading an image recorded on a first surface and a second surface of a sheet, the image processing apparatus comprising a conveying path comprising a first conveying path formed in a substantially plate shape, a second conveying path disposed below the first conveying path and a curved conveying path disposed between the first conveying path and the second conveying path, a conveying mechanism configured to convey the sheet along a conveying direction from the first conveying path to the second conveying path through the curved conveying path, a first image reading section disposed below the first conveying path and comprising a first image sensor which reads the image recorded on the first surface of the sheet conveyed along the first conveying path at a first image reading position, a second image reading section comprising a second image sensor which reads the image recorded on the second surface of the sheet conveyed along the second conveying path from below the second conveying path at a second image reading position, and an upper cover configured to rotate between a closed position where the first conveying path is partly covered and an open position where the first conveying path is exposed, wherein at least the first conveying path is exposed when the upper cover is in the open position. 
     According to the present invention, an image recorded on both front and back surfaces of a sheet can be read without using a reverse conveying path. Moreover, since the upper cover can rotate between the closed position and the open position, a jamming prevention operation can be easily carried out while being compact. 
     Other objects, features, and advantages of embodiments of the present invention will be apparent to persons of ordinary skill in the art from the following description of preferred embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an image processing apparatus according to an embodiment of the present invention. 
         FIG. 2  is a perspective view of the image processing apparatus according to the embodiment of the present invention. 
         FIG. 3  is a perspective view of the image processing apparatus according to the embodiment of the present invention. 
         FIG. 4  is a sectional view taken along line IV-IV in  FIG. 1 . 
         FIG. 5  is a sectional view of the image processing apparatus according to the embodiment of the present invention. 
         FIG. 6  is an enlarged view of the main portion in  FIG. 4 . 
         FIG. 7  is a layout of a driving system of the image processing apparatus according to the embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will hereunder be described in detail on the basis of preferred embodiments with reference to the drawings as required. 
     [General Structure of Image Processing Apparatus] 
       FIG. 1  is a perspective view of an image processing apparatus  10  according to an embodiment of the present invention. 
     The image processing apparatus  10  includes an image reading device  20 , an automatic document feeder (ADF)  11  disposed at the upper portion of the image reading device  20 , and an operation panel  40  provided at the front side of the image reading device  20 . The ADF  11  is rotatably provided with respect to the image reading device  20 . Therefore, the ADF  11  can be used to open and close the upper side of the image reading device  20  (see  FIG. 2 ). When a user perform a reading operation without using the ADF  11 , the user opens the ADF  11  and place original sheets on a predetermined position on an after-mentioned moving reading glass  80 . Then, the user closes the ADF  11  and operates the operation panel  40 , and thereby can read an image of an original sheet placed on the moving reading glass  80 . 
       FIG. 2  is a perspective view of the image processing apparatus  10  in a state in which the ADF  11  is open with respect to the image reading device  20 . Actually, a white original pressing plate is disposed on a surface opposing almost whole surface of the moving reading glass  80  of a lower surface  31  of a body frame  30  of the ADF  11 , but the original pressing plate is omitted in  FIG. 2 .  FIG. 3  is a perspective view of the image processing apparatus  10  in a state in which an upper cover  32  (an example of an upper cover according to the present invention) of the ADF  11  is open.  FIG. 4  is a sectional view taken along line IV-IV in  FIG. 1 . 
     The ADF  11  is disposed so as to cover the upper side of the image reading device  20 , and can change its position between a “closed position” shown in  FIG. 1  and an “open position” shown in  FIG. 2 , as mentioned above. As shown in  FIGS. 3 and 4 , the ADF  11  includes an original tray  12  (an example of a feed tray according to the present invention) on which original sheets are placed, and a sheet-discharge tray  14  to which the original sheets are discharged. The original tray  12  and the sheet-discharge tray  14  are disposed vertically in two levels. More specifically, the original tray  12  is disposed above the sheet-discharge tray  14 . In the embodiment, the sheet-discharge tray  14  has a recessed portion formed in the body frame  30  of the ADF  11 . 
     The ADF  11  conveys an original sheet drawn out from the original tray  12  along a U-turn conveying path  16  (an example of a conveying path, a conveying path according to the present invention), and discharges the original sheet to the sheet-discharge tray  14 . The original tray  12  can hold a plurality of original sheets in a stacked state. In a case that images are recorded on both a front surface and a back surface of the original sheet, the original sheets are held in the stacked state in order of a first page as an uppermost surface, a third page, a fifth page, and so on, that is, odd pages face upward. Even pages are back surfaces of the odd pages and face downward. The ADF  11  continuously takes out the original sheets held in the stacked state one at a time from the original tray  12 . The original sheets taken out from the original tray  12  are oriented in a direction toward the sheet-discharge tray  14  along the U-turn conveying path  16  (that is, a conveying direction), and are automatically conveyed to the sheet-discharge tray  14 . The ADF  11  also includes an image sensor  24 . As shown in  FIG. 4 , when the original sheet is conveyed along the conveying path  16 , the image sensor  24  reads an image recorded on a first surface (back surface) of the original sheet. For the image sensor  24 , a contact image sensor (CIS) or a charged coupled device (CCD) can be typically used, but in this embodiment the image sensor  24  is a CIS. By using a CIS as the image sensor  24 , the image sensor  24  can be downsized, and the ADF  11 , eventually, the image processing apparatus  10  can be downsized. 
     The image reading device  20  includes a contact glass  22 . The contact glass  22  is disposed at the upper surface of the image reading device  20 . An image sensor  25  is provided below the contact glass  22 . When conveying the original sheet along the U-turn conveying path  16 , the image sensor  25  reads an image recorded on a second surface (front surface) of the original sheet. The image sensor  25  also can read the image on the original sheet placed on the moving reading glass  80  while moving along an after-mentioned slide shaft  78 . For the image sensor  25 , a CIS or a CCD is also typically used, but in this embodiment the image sensor  25  is also a CIS. The image reading device  20  may have any structure as long as the ADF  11  is applicable. But, by using a CIS as the image sensor  25 , the image sensor  25  can be downsized, and the image reading device  20 , eventually, the image processing apparatus  10  can be downsized. 
     The embodiment exemplifies the case in which the present invention is carried out by using the image reading device  20  and the ADF  11  applicable thereto. However, the present invention may be carried out by using a copier or a multi-function device (MFD) which is mounted on top of an image recording device that records an image by adhering an image recording material (such as toner or ink) to a recording sheet. 
     [U-Turn Conveying Path] 
     As shown in  FIG. 4 , the U-turn conveying path  16  includes a first conveying path  26  (an example of a first conveying path according to the present invention), a curved conveying path  27  (an example of a curved conveying path according to the present invention), and a second conveying path  28  (an example of a second conveying path according to the present invention). That is, the U-turn conveying path  16  is formed in a substantially U shape so that the original sheet placed on the original tray  12  is conveyed to the sheet-discharge tray  14 . As shown in  FIG. 4 , the first conveying path  26  extends leftwards from the original tray  12 . The original sheets to be conveyed are supplied to the first conveying path  26  by a sheet-feed unit  50  (an example of a feed unit according to the present invention), as mentioned later. In this embodiment, more specifically, as shown in  FIG. 6 , the first conveying path  26  is a conveying path from a left side of after-mentioned conveying roller  61  and pinch roller  65  to a nip point of after-mentioned main roller  64  and pinch roller  62 . A range of the first conveying path  26  is indicated by an arrow  26 A. The first conveying path  26  is formed in a substantially plate shape, as shown in  FIGS. 3 and 6 . The first conveying path  26  includes an image reading position  19  (an example of a first image reading position according to the present invention) where the image sensor  24  reads the first surface of the original sheet. 
     The curved conveying path  27  is connected with the first conveying path  26 , and is curved downward in an arc shape. More specifically, as shown in  FIG. 6 , the curved conveying path  27  is a conveying path from a nip point of after-mentioned main roller  64  and pinch roller  62  to an after-mentioned opening  84 . A range of the curved conveying path  27  is indicated by an arrow  27 A. 
     The second conveying path  28  is connected with the curved conveying path  27 , and extends to the upper right in the figure toward the sheet-discharge tray  14  in  FIGS. 4 and 6 . More specifically, as shown in  FIG. 6 , the second conveying path  28  is a conveying path from an after-mentioned opening  84  to a left side of an after-mentioned discharge unit  70  (a discharge roller  72  and a pinch roller  74 ). A range of the second conveying path  28  is indicated by an arrow  28 A. The second conveying path  28  includes an image reading position  21  (an example of a second image reading position according to the present invention) where the image sensor  25  reads the second surface of the original sheet. 
     The ADF  11  includes a housing. This housing includes a body frame  30 , the aforementioned upper cover  32 , an upper guide  34 , and an under guide  36 . The upper cover  32 , the upper guide  34 , and the under guide  36  are mounted to the body frame  30 . The housing is formed of acrylonitrile-butadiene-styrene (ABS) copolymer, polypropylene (PP), polyacetal (POM), or other types of synthetic resins. 
     The upper guide  34  and the under guide  36  are disposed vertically in two levels. By mounting the under guide  36  to the body frame  30 , the second conveying path  28  is formed between the body frame  30  and the under guide  36 . That is, the under guide  36  forms a guide surface of the second conveying path  28 . The upper guide  34  is mounted above the under guide  36 . As shown in  FIGS. 2 and 4 , an opening  84  is provided in a lower surface  31  of the ADF  11 . The opening  84  is provided at an end situated at a boundary portion between the second conveying path  28  and the curved conveying path  27 . By providing the opening  84 , the boundary portion between the second conveying path  28  and the curved conveying path  27  is exposed to the lower surface of the ADF  11 . The opening  84  is positioned across a width indicated by an arrow  85 . An after-mentioned predetermined position  18  is included in a range of the opening  84 . Therefore, when the image sensor  25  is disposed in the predetermined position  18 , the image sensor  25  can read the front surface of the original sheet at the image reading position  21 . 
       FIG. 5  is a sectional view of the image processing apparatus  10  which is taken along line IV-IV in  FIG. 1 , like  FIG. 4 . But  FIG. 5  shows the image processing apparatus  10  in a state in which the aforementioned upper cover  32  is open, unlike  FIG. 4 . 
     The upper cover  32  is rotatably supported by a support shaft  15  mounted to the left end (in  FIG. 5 ) of the body frame  30 , and can be opened and closed. That is, the upper cover  32  can change its position between a closed position (shown in  FIG. 4 ) and an open position (shown in  FIG. 5 ). When the upper cover  32  is in the closed position, as shown in  FIG. 4 , a portion extending from the first conveying path  26  to the upper guide  34  is covered by the upper cover  32 . A portion of the curved conveying path  27 , the sheet-feed unit  50 , the conveying roller  61 , the pinch roller  65  and a portion of the original tray  12  are also covered by the upper cover  32 . 
     When the upper cover  32  is in the closed position, as shown in  FIG. 6 , the first conveying path  26  is formed between the upper cover  32  and the upper guide  34 . That is, the upper cover  32  partly forms a guide surface of the first conveying path  26 . 
     As shown in  FIG. 5 , when the position of the upper cover  32  changes to the open position, the portion extending from the first conveying path  26  to the upper guide  34  is exposed. A portion of the curved conveying path  27 , the sheet-feed unit  50 , the conveying roller  61 , the pinch roller  65  and a portion of the original tray  12  are also exposed. As shown in  FIGS. 3 and 5 , the pinch roller  62  and a first white member  76  are positioned on the upper cover  32 . More specifically, a rotary shaft  62 A of the pinch roller  62  is supported by the upper cover  32  (see  FIG. 3 ). The first white member  76  is supported by the upper cover  32  via a coil spring  77 . Therefore, when the position of the upper cover  32  changes to the open position, all the first conveying path  26  and a portion of the curved conveying path  27  are exposed. As a result, when a jamming of the original sheet occurs, the user can easily carry out a jamming prevention operation by changing the position of the upper cover  32  to the open position. 
     [Sheet-Feed Unit] 
       FIG. 6  is an enlarged view of the main portion in  FIG. 4 , and shows in detail the U-turn conveying path  16  and the vicinity thereof. 
     As shown in  FIGS. 4 and 6 , a sheet-feed unit  50  is disposed adjacent to the first conveying path  26 . The sheet-feed unit  50  sequentially takes out the original sheets held in the stacked state one at a time in order from top from the original tray  12 . The sheet-feed unit  50  is provided upstream of the first conveying path  26  in the conveying direction (that is, at the right side in  FIGS. 4 and 6 ). The sheet-feed unit  50  includes a take-in roller  52  and a separation roller  54  having a rotary shaft  56 . As is clear from  FIG. 3 , both ends of the rotary shaft  56  are supported by the body frame  30 . The separation roller  54  is secured to the almost center of the rotary shaft  56 . The rotary shaft  56  is rotated in a predetermined direction (clockwise in  FIG. 4 ) by an ADF motor (not shown) serving as a driving source. The separation roller  54  is rotated by rotating the rotary shaft  56 . 
     An arm  58  is supported by the rotary shaft  56  through a bearing. The arm  58  extends toward upstream in the conveying direction from the rotary shaft  56 . The take-in roller  52  is disposed an end upstream of the arm  58  in the conveying direction. The arm  58  is rotated through a predetermined driving transmission mechanism (not shown) by using the ADF motor serving as the driving source. Therefore, the arm  58  can move up and down with respect to the rotary shaft  56  as center. The take-in roller  52  is also connected to the rotary shaft  56  through a predetermined driving transmission mechanism. By this, if the rotary shaft  56  rotates, not only the separation roller  54 , but also the take-in roller  52  rotates clockwise. The outside diameter of the take-in roller  52  and the outside diameter of the separation roller  54  are set the same, so that both of the rollers  52  and  54  are rotated at the same peripheral speed. 
     The sheet-feed unit  50  also includes a separation portion  57 . The separation portion  57  is disposed so as to oppose the separation roller  54 . The separation portion  57  is configured to press-contact the roller surface of the separation roller  54 . The separation portion  57  is typically formed of a cork piece or an elastomer, and provides a large friction force between it and an original sheet. Therefore, if a plurality of original sheets are inserted between the separation portion  57  and the separation roller  54 , at a nip point  89  (see  FIG. 7 ) of the separation roller  54 , only the original sheet that is in contact with the separation roller  54  is separated from other original sheets and conveyed toward the U-turn conveying path  16 . 
     A plurality of original sheets in a stacked state are placed on the original tray  12 . At this time, an original sheet is place in a state that an end of each original sheet is inserted into the sheet-feed unit  50 . Furthermore, at this time, the original sheets are placed on the original tray  12  with the front surface (a surface of odd pages, an upper surface, a second surface) faced upward. An image recorded on the back surface (a surface of even pages, a lower surface, a first surface) of the original sheet taken out from the original tray  12  by the ADF  11  is read by the image sensor  24 . The original sheet is further conveyed along the U-turn conveying path  16 , and its front and back surfaces are reversed when the original sheet passes along the curved conveying path  27 . Then, an image recorded on the front surface of the original sheet is read by the image sensor  25 . Thereafter, the original sheet discharged to the sheet-discharge tray  14  has its front surface faced downward and is placed on the sheet-discharge tray  14 . Therefore, even if a plurality of the original sheet are conveyed by the ADF  11  to read the image thereon, an order of the page of the original sheets will not be changed from a case that the original sheets are placed on the original tray  12  to a case that the original sheets are stacked on the discharge tray  14 , though the original sheets will be turned upside down. 
     [Conveying Unit] 
     As shown in  FIG. 6 , a conveying unit  60  (an example of a conveying mechanism according to the present invention) includes a conveying roller  61  (a first conveying roller), a main roller  64  (an example of a driving roller according to the present invention), a pinch roller  62  (second conveying roller), and a pinch roller  63  (third conveying roller). 
     The conveying roller  61  is disposed adjacent to the first conveying path  26 . More specifically, the conveying roller  61  is disposed immediately in front of the first conveying path  26  in the conveying direction, and is positioned more downstream in the conveying direction than the separation roller  54 . The conveying roller  61  form a pair of rollers with the pinch roller  65  (an example of a pair of conveying rollers according to the present invention). The original sheet conveyed from the separation roller  54  is nipped by the conveying roller  61  and the pinch roller  65 . The conveying roller  61  rotates to supply the original sheet to the first conveying path  26 . 
     As shown in  FIG. 6 , the main roller  64  is disposed at an end portion (left end portion in  FIG. 6 ) of the body frame  30 . The body frame  30 , the upper cover  32  of the ADF  11 , and the main roller  64  form the curved conveying path  27 . That is, the body frame  30 , an inner wall surface of the upper cover  32 , and the outer peripheral surface of the main roller  64  form a guide surface of the curved conveying path  27 . As is clear from  FIG. 3 , the main roller  64  comprises three rollers that are supported by only one driving shaft  67  (an example of a driving shaft according to the present invention) and are disposed at a predetermined interval. The central main roller  64  of the three main rollers  64  forms a pair of rollers with the pinch roller  62  (an example of a pinch roller according to the present invention), and a pair of rollers with the pinch roller  63  (an example of a pinch roller according to the present invention). The pinch roller  62  is disposed at a boundary between the first conveying path  26  and the curved conveying path  27  as mentioned above. The original sheet conveyed along the first conveying path  26  is nipped by the main roller  64  and the pinch roller  62 , and is conveyed along the curved conveying path  27  in the conveying direction. The pinch roller  63  is disposed downstream of the curved conveying path  27  in the conveying direction. The original sheet conveyed along the curved conveying path  27  is nipped by the main roller  64  and the pinch roller  63 , and is conveyed toward the second conveying path  28 . Although, in the embodiment, the main roller  64  comprising only one driving shaft  67  forms pairs of rollers with the pinch rollers  62  and  63 , a plurality of driving rollers that form pairs with these rollers  62  and  63 , respectively, may be provided along the curved conveying path  27 . This is a configuration in which the plurality of the driving rollers each comprising a driving shaft are provided along the curved conveying path  27 , a pinch roller is provided on each of the plurality of the driving rollers. The configuration of this embodiment, in which the main roller  64  comprising only one driving shaft  67  forms pairs of rollers with the pinch rollers  62  and  63 , can realize reduction of configuration and downsizing by reducing the number of the driving rollers and a drive mechanism. At a position along the curved conveying path  27  between the pinch rollers  62  and  63 , other pinch roller may be provided to press the main roller  64 . 
     The conveying roller  61  and the main roller  64  include driving shafts  66  and  67 , respectively. These driving shafts  66  and  67  are driven through a predetermined driving transmission mechanism by the ADF motor (not shown) as the driving source. By this, the original sheet is conveyed in the conveying direction along the first conveying path  26  and the curved conveying path  27 . 
     [Discharge Unit] 
     As shown in  FIG. 6 , a discharge unit  70  includes a discharge roller  72  and a pinch roller  74 . The discharge roller  72  includes a driving shaft  71 . The driving shaft  71  is driven through a predetermined driving transmission mechanism by the ADF motor serving as the driving source. The discharge roller  72  is disposed immediately behind the second conveying path  28  in the conveying direction. The discharge roller  72  and the pinch roller  74  nip the original sheet conveyed along the second conveying path  28 , and convey it in the conveying direction. Since the second conveying path  28  extends obliquely upward as mentioned above, the discharge roller  72  is positioned above the sheet-discharge tray  14 . Therefore, the original sheet that passes the discharge roller  72  and that is discharged falls onto the sheet-discharge tray  14 . Furthermore, since the discharge unit  70  is disposed below the sheet-feed unit  50 , more specifically below the take-in roller  52 , the second conveying path  28  is longer than the first conveying path  26 , as shown by arrows  26 A and  28 A in  FIG. 6 . Therefore, even if an angle that the second conveying path  28  slants obliquely upward is not so large, that is, even if the second conveying path  28  has a gentle slant, an after-mentioned lift amount  88  can be large. As a result, a large amount of the original sheets can be held on the discharge tray  14 , while a height of the ADF  11  can be downsized vertically. 
     The discharge roller  72  and the pinch roller  74  may not be disposed immediately behind the second conveying path  28  in the conveying direction. If the original sheet can be guided from the second conveying path  28  to the discharge tray  14 , the discharge roller  72  and the pinch roller  74  may be disposed in the second conveying path  28  in the conveying direction. 
     [First Image Reading Section] 
     As mentioned above, the first image reading section (an example of a first image reading section according to the present invention) is provided at the ADF  11 . The first image reading section comprises an image sensor  24  (an example of a first image sensor according to the present invention), a first image reading glass  75  (an example of a first platen according to the present invention), a first white member  76  (an example of a first pressing member according to the present invention) and a coil spring  77  (an example of a first urging member according to the present invention). The first image reading glass  75  is tabular and a surface of the first image reading glass  75  is disposed along the substantially planate first conveying path  26 . The first image reading glass is disposed between the conveying roller  61  and the pinch roller  62 , and the image sensor  24  is provided so as to face the first conveying path  26  from below via the first image reading glass  75 . The image sensor  24  is disposed in space enclosed with the first conveying path  26 , the main roller  64  and the second conveying path  28 . Therefore, the original sheet that is conveyed along the substantially planate first conveying path  26  passes near the image sensor  24  along the first image reading glass  75 . Here, an image recorded on the back surface (first surface) of the original sheet is read at the image reading position  19  by the image sensor  24 . The first white member  76  is disposed so as to oppose the image sensor  24  via the first image reading glass  75 . As shown in  FIG. 3 , the first white member  76  has almost the same length as the first image reading glass  75  in a longitudinal direction. A coil spring  77  is provided at the first white member  76 . By this, the first white member  76  is resiliently urged toward the first image reading glass  75 , that is, the image sensor  24 . Therefore, the first white member  76  pushes the original sheet that is conveyed along the first conveying path  26  against the first image reading glass  75 . As a result, a distance between the image sensor  24  and the back surface of the original sheet becomes constant, and a good image reading operation can be performed by a CIS whose depth of focus is smaller than a CCD. At least a surface of the first white member  76  that faces the first image reading glass  75  is white in color. By this, at a predetermined timing before reading an image, a processing of taking a white standard when the image sensor  24  reads an image is performed, but the processing is known and is not described here. 
     As mentioned above, the configuration of this embodiment, in which a plurality of the pinch rollers  62  and  63  are pressed against the main roller  64  comprising only one driving shaft  67 , can realize reduction of configuration and downsizing by reducing the number of the driving rollers and a drive mechanism. But in this case the first image reading section needs to be disposed on the substantially planate first conveying path  26 . 
     If the first image reading section is disposed downstream of the opening  84  of the second conveying path  28  in the conveying direction, a jamming prevention operation becomes more difficult, and the sheet-feed unit  50 , the conveying roller  61  and the pinch roller  65  will be disposed above the first image reading section. By this, the image processing apparatus  10  will be larger vertically in size. 
     The first white member  76  of this embodiment is made of a sheeted member, but may be made of a rotary roller with a white surface instead. In this case, the rotary roller may have almost the same length as the first image reading glass  75  in a longitudinal direction and may be disposed so as to contact the first image reading glass  75  at the first image reading position  19 . In this case, the rotary roller may be resiliently urged toward the first image reading glass  75 , that is, the image sensor  24 , by an urging member such as the coil spring  77 . 
     [Second Image Reading Section] 
     As mentioned above, the second image reading section (an example of a second image reading section according to the present invention) is provided at a side of the image reading device  20 . The second image reading section comprises an image sensor  25  (an example of a second image sensor according to the present invention), a stationary reading glass  79 , a second white member  82  and a coil spring  83 . The image sensor  25  is slidably supported by a slide shaft  78 . The slide shaft  78  is secured to a housing of the image reading device  20 , and extends in the illustrated left-right direction as shown in  FIGS. 4 and 6 . That is, the slide shaft  78  extends in the original-sheet conveying direction and in a direction opposite thereto. The image sensor  25  slides through a predetermined driving transmission mechanism by a motor (not shown) as a driving source. An example of the driving transmission mechanism in this case is a pulley-belt mechanism. 
     The contact glass  22  of the image reading device  20  is divided in two. That is, the contact glass  22  includes a stationary reading glass  79  and a moving reading glass  80 . When the ADF  11  is not used, original sheets are placed at a predetermined position on the moving reading glass  80  one at a time by the user of the image processing apparatus. Then, images that are recorded on the original sheets facing the moving reading glass  80  are read while sliding the image sensor  25  along the slide shaft  78 . 
     When the ADF  11  is used, the original sheets continuously pass the stationary reading glass  79 . An original separation member  81  is provided between the stationary reading glass  79  and the moving reading glass  80 . The original separation member  81  takes up from the stationary reading glass  79  the original sheet that has entered the second conveying path  28  and that has contacted the stationary reading glass  79 . This causes the original sheet to separate from the stationary reading glass  79  and to be conveyed along the second conveying path  28 . 
     When the ADF  11  is used, the image sensor  25  is moved to a predetermined position  18  and is stopped. By stopping the image sensor  25  at the predetermined position  18 , the image sensor  25  is provided so as to face the second conveying path  28  from below via the stationary reading glass  79 . The predetermined position  18  is situated at an end portion of the stationary reading glass  79  and adjacent to the original separation member  81 . The original sheet is conveyed between the stationary reading glass  79  and the second white member  82  and reaches an actual image reading position  21 , and is, then, taken up from the stationary reading glass  79  by the original separation member  81 . The original sheet is always exposed from the opening  84  when it passes the image reading position  21 . That is, an image that has been recorded on the front surface of the original sheet is exposed from the opening  84 . The image sensor  25  in a standby state at the predetermined position  18  reads the exposed image at the image reading position  21 . 
     A second white member  82  is disposed at a position corresponding to the image reading position  21 . As shown in  FIG. 2 , the second white member  82  has almost the same length as the stationary reading glass  79  in a longitudinal direction. More specifically, the second white member  82  is provided at the under guide  36  of the ADF  11  via the coil spring  83 . The second white member  82  faces the image sensor  25  in the standby state at the predetermined position  18  via the stationary reading glass  79 . Therefore, the second white member  82  is resiliently urged toward the stationary reading glass  79 , that is, the image sensor  25 . When an edge of the original sheet that is conveyed along the second conveying path  28  reaches the second white member  82 , the original sheet moves into a space between the second white member  82  and the stationary reading glass  79 . The second white member  76  pushes the original sheet against the stationary reading glass  79 . As a result, a distance between the image sensor  25  and the front surface of the original sheet becomes constant, and a good image reading operation can be performed by a CIS whose depth of focus is smaller than a CCD. At least a surface of the second white member  82  that faces the stationary reading glass  79  is white in color. By this, at a predetermined timing before reading an image, a processing of taking a white standard when the image sensor  25  reads an image is performed, but the processing is known and is not described here. 
     The second white member  82  of this embodiment is made of a sheeted member, but may be made of a rotary roller with a white surface instead. In this case, the rotary roller may have almost the same length as the stationary reading glass  79  in a longitudinal direction and may be disposed so as to contact the stationary reading glass  79  at the second image reading position  21 . In this case, the rotary roller may be resiliently urged toward the stationary reading glass  79 , that is, the image sensor  25 , by an urging member such as the coil spring  83 . 
     If the configuration of this embodiment is used, the first image reading section is disposed below (lower than) the sheet-feed unit  50 . The first white member  76  and the first image sensor  24  of the first image reading section, and the second white member  82  and the coil spring  83  of the second image reading section are vertically disposed in space between the main roller  64  comprising only one drive shaft  67  and the sheet-feed unit  50 . The first white member  76  and the first image sensor  24  of the first image reading section, and the second white member  82  and the coil spring  83  of the second image reading section are also vertically disposed in space between the curved conveying path  27  and the sheet-feed unit  50 . As a result, the image processing apparatus  10  can be downsized vertically. 
       FIG. 7  is a layout of a driving system of the ADF  11 . 
     As shown in  FIG. 7 , in the ADF  11  according to the embodiment, the conveying roller  61  and the pinch roller  62  are positioned between the pinch roller  63  and the discharge roller  72 . More specifically, a distance  91  between the pinch roller  63  and the discharge roller  72  is equal to the distance between a first span point P 1  and a second span point P 2 . The first span point P 1  is a nip point between the pinch roller  63  and the main roller  64 . The second span point P 2  is a nip point between the discharge roller  72  and the pinch roller  74 . A distance  92  between the conveying roller  61  and the pinch roller  62  is the distance between a third span point P 3  and a fourth span point P 4 . The third span point P 3  is a nip point between the conveying roller  61  and the pinch roller  65 . The fourth span point P 4  is a nip point between the pinch roller  62  and the main roller  64 . The distance  91  is greater than the distance  92 , and the conveying roller  61  and the pinch roller  62  are positioned within an imaginary area  95  formed by imaginary lines  93  and  94  extending upward from the first span point P 1  and the second span point P 2 , respectively. 
     The nip point  89  of the separation roller  54  exists within the imaginary area  95 . However, the nip point  89  exists outside an imaginary area  98  formed by an imaginary line  96  and  97  extending upward from the third span point P 3  and the fourth span point P 4 , respectively. Further, the nip point  89  is disposed closer to the second conveying path  28  than the third span point P 3 , that is, below the third span point P 3 . 
     [Operation of Image Processing Apparatus] 
     In the image processing apparatus  10 , the ADF  11  operates and conveys original sheets as follows. 
     As shown in  FIG. 6 , an original sheet separated from other original sheets on the original tray  12  by the sheet-feed unit  50  is conveyed to the first conveying path  26  by the conveying roller  61  and the pinch roller  65 . When the original sheet is conveyed along the first conveying path  26 , an image that has been recorded on its back surface is scanned at the image reading position  19  by the image sensor  24 . The original sheet is conveyed along the curved conveying path  27  by the main roller  64  and the pinch roller  62 , and then is conveyed to the second conveying path  28  by the main roller  64  and the pinch roller  63 . The original sheet that has entered the second conveying path  28  is temporarily exposed from the opening  84 . This time, since an image of the original sheet is scanned by the ADF  11 , the image sensor  25  moves to the predetermined position  18 . Therefore, when the original sheet passes the opening  84 , an image that has been recorded on the front surface of the original sheet is scanned at the image reading position  19  by the image sensor  25 . Thereafter, the original sheet is discharged to the sheet-discharge tray  14  by the discharge roller  72 . 
     Since the second conveying path  28  is tilted obliquely upward, the original sheet that has been conveyed along the second conveying path  28  is raised upward and, then, falls upon the sheet-discharge tray  14 . Here, as shown in  FIG. 8 , the first distance  91  between the discharge roller  72  and the pinch roller  63  is greater than the second distance  92  between the conveying roller  61  and the pinch roller  62 . Therefore, a lift amount  88  of the original sheet that is conveyed along the second conveying path  28  is large. Consequently, in the interior of the image processing apparatus  10 , a large area or space for stacking the discharged original sheets upon each other is ensured. Moreover, since the conveying roller  61  and the pinch roller  62  are disposed in the imaginary area  95 , the conveying roller  61  and the pinch roller  62  can be disposed vertically close to the pinch roller  63  and the discharge roller  72 . That is, the conveying roller  61 , the pinch roller  62 , the pinch roller  63 , and the discharge roller  72  are compactly disposed vertically. 
     Since the conveying roller  61  and the other rollers for conveying the original sheet are compactly laid out vertically, a compact design of the image processing apparatus  10  is possible. Moreover, as mentioned above, since a large area for stacking the discharged original sheets upon each other is provided, the image processing apparatus  10  can handle the required and sufficient number of original sheets while being compact. 
     In the embodiment, since the original tray  12  is disposed above the sheet-discharge tray  14 , the original sheet is moved downward through the U-turn conveying path  16  from the original tray  12  disposed above the sheet-discharge tray  14 , and is held by the sheet-discharge tray  14 . Therefore, the user can easily take out any discharged original sheet. That is, handling of original sheets  58  is facilitated. 
     In the embodiment, since the conveying roller  61  is disposed close to the first conveying path  26 , the distance  91  can be made very small. Therefore, the horizontal dimension (that is, the left-right dimension in  FIG. 4 ) of the image processing apparatus  10  is small, so that the apparatus can be more compactly designed. 
     In particular, in the embodiment, the opening  84  is provided at the lower surface of the ADF  11 . As mentioned above, the original sheet is exposed from the opening  84  when the image sensor  25  scans an image. By providing the opening  84 , the user can deliberately take out the original sheet from the opening  84 . Therefore, if what is called a jamming prevention operation needs to be performed on the original sheet that is being conveyed along the curved conveying path  27 , the original sheet is immediately pulled out from the opening  84 . That is, the jamming prevention operation is facilitated. 
     In addition, in the embodiment, as shown in  FIG. 8 , since the nip point  89  of the separation roller  54  is disposed at the aforementioned position, the separation roller  54  and the separation portion  57  for supplying the original sheet to the conveying roller  61  can be disposed lower than the conveying roller  61 . Therefore, it is possible to make the image processing apparatus  10  thin and compact. 
     In this embodiment, the image processing apparatus  10  is an image processing apparatus for a two-side reading, which has a configuration in which images recorded on both sides of the original sheet are read by two image sensors  24  and  25 . However, by using the same body frame as the body frame  30  and reducing a part of the components, an image processing apparatus for a one-side reading, in which an image recorded on one side of the original sheet is read while conveying from the original tray to the discharge tray, can be inexpensively configured. This is because a part of the components is configured to be removable. In this case, for example, the image sensor  24 , the conveying roller  61 , the pinch roller  65 , the drive shaft  66 , the first image reading glass  75 , the first white member  76  and the coil spring  77  may be reduced. The drive mechanism for driving the drive shaft  66  of the conveying roller  61  may be also reduced. Instead of these components, other replacements required to configure the image processing apparatus for a one-side reading may be replaced as required. That is, instead of the first white member  76  and the first image reading glass  75 , for example, guide members which configure the first conveying path  26  may be replaced separately.