Patent Publication Number: US-9421810-B2

Title: Page-turning device and document camera system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a Divisional of U.S. application Ser. No. 14/094,295, filed Dec. 2, 2013, which is based upon and claims the benefit of priority under 35 USC 119 of Japanese Patent Application No. 2012-275300, filed Dec. 18, 2012, the entire contents of both of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a page-turning device and a document camera system. 
     2. Description of Related Art 
     Conventionally, as an automatic page-turning device to turn pages of a book or the like, there is known a page-turning device which sticks to each page of piled pages to turn pages, which is disclosed, for example, in Japanese Patent Application Laid-Open Publication No. H05-155179. 
     SUMMARY OF THE INVENTION 
     The sticking to the page is released at a destination position. After the release, there is a possibility that the page returns to the departure position due to resilience of the page itself. 
     Hence, objects of the present invention include turning pages more reliably by preventing the pages from returning to the departure position from the destination position. 
     In order to achieve at least one of the objects, according to a first aspect of the present invention, there is provided a page-turning device turning a page of a book including: a turning unit which holds the page at a departure position of the page of the book being opened and which releases the holding of the page at a destination position of the page; and a blower which sends air above the page at the departure position to blow against the page at the destination position. 
     In order to achieve at least one of the objects, according to a second aspect of the present invention, there is provided a document camera system including: the page-turning device; and an image pickup unit which images the page of the book. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinafter and the appended drawings, which are given byway of illustration only and thus are not intended as a definition of the limits of the present invention, wherein: 
         FIG. 1  is a perspective view schematically showing the configuration of a document camera system according to an embodiment of the present invention; 
         FIG. 2A  is a top view showing the configuration of the essential part of the document camera system in  FIG. 1 ; 
         FIG. 2B  is a side view showing the configuration of the essential part of the document camera system in  FIG. 1 ; 
         FIG. 3  is an elevation view showing a route of a sticking part provided on the top end of an arm part according to the embodiment; 
         FIG. 4A ,  FIG. 4B  and  FIG. 4C  schematically illustrate how inclination of a drive shaft of a first drive unit according to the embodiment affects a page-turning operation; 
         FIG. 5A ,  FIG. 5B  and  FIG. 5C  are respectively a top view, a side view and an elevation view, schematically showing difference of routes of the sticking part between a case where the drive shaft of the first drive unit is horizontal and a case where the drive shaft is inclined with respect to the vertical line standing perpendicular to the seam; 
         FIG. 6  is a schematic view schematically showing the configuration of the arm part according to the embodiment; 
         FIG. 7  is an elevation view schematically showing the configuration of the sticking part according to the embodiment; 
         FIG. 8  is a perspective view schematically showing the structure of an adhesive component according to the embodiment; 
         FIG. 9A  and  FIG. 9B  illustrate a process of removing the adhesive component when the adhesive power has weakened; 
         FIG. 10  is a block diagram showing the main control configuration of the document camera system according to the embodiment; 
         FIG. 11  is a flowchart of page-turning processing by the page-turning device of the embodiment; 
         FIG. 12  is an elevation view showing a route and a rotating direction of the sticking part in an outward movement of the arm part according to the embodiment; 
         FIG. 13  is a timing chart showing drive timings of the first drive unit and the second drive unit in the page-turning operation for one page according to the embodiment; 
         FIG. 14  is a schematic view showing a modification of the sticking part; 
         FIG. 15  shows a modification of the embodiment illustrating a circuit in a case that an air volume of a fan unit of a blower is switched; and 
         FIG. 16  shows a modification of the embodiment and is a perspective view schematically showing the configuration of a document camera system with two blowers. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Though various technical limitations which are preferable to carry out the present invention are added to the after-described embodiment, the scope of the invention is not limited to the following embodiment and the illustrated examples. 
       FIG. 1  is a perspective view schematically showing the configuration of a document camera system according to an embodiment of the present invention.  FIG. 2A  and  FIG. 2B  illustrate the configuration of the essential part of the document camera system, wherein  FIG. 2A  is a top view, and  FIG. 2B  is a side view.  FIG. 3  is an elevation view showing the essential part of the document camera system. In the explanation hereinafter, pages P of a book B are turned from left to right. 
     As shown in  FIG. 1  to  FIG. 3 , a document camera system  1  includes: a document camera  2  as an image pickup unit which picks up images of the pages P of the book B; a page-turning device  3  which turns the pages P of the book B; and a personal computer  4  connected to the document camera  2  and the page-turning device  3  such that the computer  4  can communicate with the document camera  2  and the page-turning device  3 . 
     The document camera  2  includes a stand part  21  and a camera  22  attached to the upper end of the stand part  21 . The stand part  21  is inclinable in the front-back direction and the left-right direction, and extensible in the up-down direction, so that a positional relationship of the book B and the camera  22  can be adjusted. A lens of the camera  22  faces downward such that the book B comes within an angle of view. A position-adjustment mechanism is disposed at the joining portion of the camera  22  and the stand part  21 , so that the facing direction of the lens of the camera  22  can be adjusted. 
     The page-turning device  3  includes: a support base  6  which supports the book B being opened; a turning unit  30  which holds the page P at a departure position of the page P of the book B and which releases the holding of the page P at a destination position of the page P; a blower  5  which sends air above the page P at the departure position to blow against the page P at the destination position; and a control unit  36  which controls these parts and the like. 
     As shown in  FIG. 3 , the support base  6  includes a couple of support plates  61 ,  62 . The support base  6  can be folded up by using a hinge, which is not shown in drawings. When the pages P of the book B are turned from left to right as shown in  FIG. 3 , a first support plate  61  of the support plates  61 ,  62  which is disposed on the left is laid on the desk D, and a second support plate  62  which is disposed on the right is placed on the desk D such that the second support plate  62  is inclined at a predetermined angle as if the second support plate  62  approaches the first support plate  61 . The page P at the departure position is placed on the first support plate  61 , while the page P at the destination position is placed on the second support plate  62 . 
     When the pages P of the book B are turned from right to left, the second support plate  62  which is disposed on the right is laid on the desk D, and the first support plate  61  which is disposed on the left is placed on the desk D such that the first support plate  61  is inclined at a predetermined angle as if the first support plate  61  approaches the second support plate  62 . The page P at the departure position is placed on the second support plate  62 , while the page P at the destination position is placed on the first support plate  61 . 
     Thereby, the support base  6  supports the book B such that a destination position inclined angle between the page P at the destination position and a horizontal plane is larger than a departure position inclined angle between the page P at the departure position and the horizontal plane. Since the support base  6  can be folded up by using a hinge between the support plates  61 ,  62 , an angle between the support plates  61 ,  62  is adjustable. Therefore the destination position inclined angle θ between the page P at the destination position and the horizontal plane is adjustable. The destination position inclined angle θ is preferably adjusted to 30 to 45 degrees. 
     The turning unit  30  includes: a base  31 ; a first drive unit (drive unit)  33 , such as a motor, disposed on the base  31  and having a drive shaft  32 ; an arm part  34  which swings around the drive shaft  32 ; and a sticking part  35  attached to the top end of the arm part  34 , the sticking part  35  sticking to or separating from a page P of the book B. 
     The base  31  is disposed on a desk D such that one side of the base  31  is parallel to the upper side b 1  of the book B opened on the support base  6 . In the explanation hereinafter, “back” is defined as a side where the book B is disposed, i.e. the book B side, and “front” is defined as a side where the base  31  is disposed, i.e. the base  31  side. The seam b 2  of the book B is along the front-back direction. The base  31  includes a main base  311  and a sub base  312  which is superposed on the main base  311  and can adjust an angle α between the main base  311  and the sub base  312 . On the back end (the end on the book B side) of the sub base  312 , a hinge (not shown) is disposed. This hinge makes the angle α between the sub base  312  and the main base  311  adjustable. The sub base  312  is provided with a rotating plate  313  which is rotatable and supports the first drive unit  33 . The drive shaft  32  of the first drive unit  33  is disposed parallel to the upper surface of the rotating plate  313 . 
     When the pages P of the book B are turned from left to right, the angle of the rotating plate  313  is determined such that the back end (the end on the book B side) of the drive shaft  32  turns to right-hand side with respect to the seam b 2  of the pages P and the front end (the end on a side opposite to the book B side) of the drive shaft  32  as the base end turns to left-hand side with respect to the seam b 2  of the pages P. On the other hand, when the pages P of the book B are turned from right to left, the angle of the rotating plate  313  is determined such that the back end (the end on the book B side) of the drive shaft  32  turns to left-hand side with respect to the seam b 2  of the pages P and the front end (the end on the side opposite to the book B side) of the drive shaft  32  turns to right-hand side with respect to the seam b 2  of the pages P. 
     Whichever the turning direction is, the drive shaft  32  is inclined such that the base end of the drive shaft  32  is on a side where a departure position of the pages P exists (departure position side) with respect to the seam b 2  of the book B and also inclined at the angle α with respect to a plane on which the book B is put (horizontal plane). 
     Also, a mark  314  for locating is formed at the back end (the end on the book B side) of the sub base  312 . It is preferable to locate the base  31  such that this mark  314  is on the extension of the seam b 2 . 
     The arm part  34  is inclined with respect to the drive shaft  32  toward the book B side. As the drive shaft  32  rotates, the arm part  34  goes to and fro (shuttle operation) between the departure position and a destination position of the pages P as if the arm part  34  draws a circular arc around the drive shaft  32 . That is to say, the drive shaft  32  is a symmetry axis of swing of the arm part  34 . In the explanation hereinafter, a movement from the departure position to the destination position of the pages P is referred to as an outward movement (a motion of going), and a movement from the destination position to the departure position is referred to as a homeward movement (a motion of return). 
       FIG. 3  is an elevation view (viewed in a direction along an axis of the seam b 2  of the pages P or viewed from a plane side, the normal line of which is parallel to the seam b 2 ) showing a route of the sticking part  35  provided on the top end of the arm part  34 . As shown in  FIG. 3 , in the outward movement, the sticking part  35  on the top end of the arm part  34  moves from a position which contacts the departure position of the pages P to the destination position of the pages P as if the sticking part  35  draws a circular arc over the pages P. 
       FIG. 4A ,  FIG. 4B  and  FIG. 4C  schematically illustrate how the inclination of the drive shaft  32  affects the page-turning operation of the pages P.  FIG. 4A ,  FIG. 4B  and  FIG. 4C  show the book B placed not on the support base  6  but directly on the desk D so that the configuration can be easily understood.  FIG. 4A  illustrates a case where the drive shaft  32  is horizontally disposed on the extension of the seam b 2 . In this case, since the sticking part  35  moves along a route the symmetry axis of which corresponds to the seam b 2 , the sticking part  35  keeps in contact with the right-side page P at the destination position of the pages P without being able to separate from the page P. 
       FIG. 4B  illustrates a case where the drive shaft  32  is horizontal and inclined such that the back end of the drive shaft  32  turns to right-hand side with respect to the seam b 2  of the pages P and the front end of the drive shaft  32  as the base end turns to left-hand side with respect to the seam b 2  of the pages P. In this case, after the sticking part  35  sticks to a page P at the departure position, the arm part  34  rotates around the drive shaft  32 , and at the end point of the outward movement, the sticking part  35  separates from the book B forward. Therefore, the sticking part  35  can easily separate from the sticking page P. 
     In this case, however, the pages P cannot always be turned smoothly. One possible cause is that the distance between the book B and the sticking part  35  becomes long in the first phase to the middle phase (the ellipse S) of the page-turning operation. 
       FIG. 4C  illustrates a case where the drive shaft  32  is inclined with respect to the seam b 2  of the book B and is also inclined with respect to the horizontal plane, i.e. a case of the drive shaft  32  according to the embodiment. In this case, the distance between the book B and the sticking part  35  in the first phase to the middle phase (the ellipse S) of the page-turning is shorter than that in the case shown in  FIG. 4B . 
     To be more specific,  FIG. 5A ,  FIG. 5B  and  FIG. 5C  schematically illustrate difference of routes of the sticking part  35  between a case where the drive shaft  32  is horizontal and a case where the drive shaft  32  is inclined with respect to the horizontal plane, wherein  FIG. 5A  is a top view,  FIG. 5B  is a side view, and  FIG. 5C  is an elevation view. In  FIG. 5A ,  FIG. 5B  and  FIG. 5C , the left-right direction, the up-down direction and the vertical direction of the book B are respectively defined as an x direction, a y direction and a z direction. In  FIG. 5A ,  FIG. 5B  and  FIG. 5C , the drive shaft  32  aligns with the seam b 2  of the book B in order to clarify the point that the drive shaft  32  of the embodiment is inclined with respect to the horizontal plane. As shown in  FIG. 5A ,  FIG. 5B  and  FIG. 5C , in the case where the drive shaft  32  is horizontal (dot lines in the figures), the locus n 1  of the sticking part  35  is a straight line along the left-right direction in the top view ( FIG. 5A ), a straight line along the vertical direction in the side view ( FIG. 5B ) and a semicircle in the elevation view ( FIG. 5C ). On the other hand, in the case where the drive shaft  32  is inclined with respect to the horizontal plane (solid lines in the figures), the locus n 2  of the sticking part  35  is a circular arc being convex backward in the top view ( FIG. 5A ), a straight line with its upper end being inclined backward in the side view ( FIG. 5B ) and a deformed semicircle in the elevation view ( FIG. 5C ). The locus n 2  in  FIG. 5B  shows the locus plane of the driven sticking part  35  viewed from the side. It shows that the locus n 2  is inclined with respect to a plane (x-z plane) including the left-right direction of the book B and a normal line of the book B. 
     As is known from  FIG. 5C , the distance from the sticking part  35  to the seam b 2  when the sticking part  35  passes over the seam b 2  is shorter than the distance from the sticking part  35  to the seam b 2  when the sticking part  35  sticks to a page P at the departure position. That is to say, the locus n 2  can make the distance from the book B to the sticking part  35  when the sticking part  35  passes over the seam b 2  shorter than the locus n 1 . 
     Thus, according to the embodiment shown in  FIG. 4C , in the second phase of the page-turning, the distance between the book B (the seam b 2 ) and the sticking part  35  becomes long, so that the sticking part  35  can easily separate from the sticking page P. Also, in the first phase to the middle phase (the ellipse S) of the page-turning operation, the distance between the book B (the seam b 2 ) and the sticking part  35  becomes short, so that a page P can be slackened appropriately. Therefore, the pages P can be reliably turned. 
     In the homeward movement, the moving direction is opposite to that in the outward movement, and the sticking part  35  takes the same route as that of the outward movement, moves keeping a distance from the pages P and, in the end, sticks to another page P at the departure position of the pages P. 
     Repeating this shuttle operation progresses the page-turning operation of the pages P. 
     In the present embodiment, the drive shaft  32  is inclined with respect to the seam b 2  of the opened book B and is also inclined with respect to the horizontal plane as shown in  FIG. 4C  as an example. It is needless to say that if the drive shaft  32  is inclined with respect to either the seam b 2  or the horizontal plane, these cases have their respective effects. 
     If the drive shaft  32  is inclined only with respect to the horizontal plane, as described later, a second drive unit  37  is driven or the sticking part  35  is configured in such a way as to stay at a higher position on the right than that on the left so that the sticking part  35  can easily separate from a page P. 
     Next, specific configurations of the arm part  34  and the sticking part  35  will be explained.  FIG. 6  is a schematic diagram schematically showing the configuration of the arm part  34 . The arm part  34  is a plate component the base end of which is attached to the drive shaft  32  as shown in  FIG. 6 . The sticking part  35  is attached to the top end of the arm part  34  via the second drive unit  37  such as a motor. 
     The second drive unit  37  is disposed such that a drive shaft  39  of the second drive unit  37  is along a direction perpendicular to the longitudinal direction of the arm part  34 . The sticking part  35  is removably attached to the drive shaft  39 , and the sticking part  35  rotates as the drive shaft  39  rotates. 
       FIG. 7  is an elevation view schematically showing the configuration of the sticking part  35 . As shown in  FIG. 7 , the sticking part  35  includes a columnar rotating roller  351  and an adhesive component  352  wound around the rotating roller  351 . 
     There has been desire to improve working efficiency in replacement of the sticking parts  35  with respect to the drive shaft  39  of the second drive unit  37 . Hence, the rotating roller  351  is made of an elastic body such as a sponge, and a fit hole  353  into which the drive shaft  39  is fitted is formed at the center of the rotating roller  351 . Other than the sponge, examples of the elastic body include rubber and foam. The inner diameter of the fit hole  353  is formed to be smaller than the outer diameter of the drive shaft  39 . By pushing the drive shaft  39  into the fit hole  353 , the rotating roller  351  contracts, and the drive shaft  39  fits in the fit hole  353 . Consequently, at the replacement, the rotating roller  351  can be removed from the drive shaft  39  only by pulling the rotating roller  351  to be detached from the drive shaft  39 . Thus, since the rotating roller  351  is elastic, the sticking part  35  can be easily put on and removed from the drive shaft  39 , and accordingly the sticking part  35  can be easily replaced with another. 
       FIG. 8  is a perspective view schematically showing the configuration of the adhesive component  352 . As shown in  FIG. 8 , the adhesive component  352  is sheet-shaped and has, for example, a double-sided adhesive structure like a double-sided tape. The adhesive component  352  has a two-layer structure of a weak adhesive layer  354  and a strong adhesive layer  355 . The weak adhesive layer  354  is provided on a side which sticks to the book B (surface side). The weak adhesive layer  354  has: weak adhesive power so that pieces of the weak adhesive layer  354  do not remain after the adhesive component  352  is removed; and a property that the weak adhesive layer  354  can be used multiple times. On the other hand, the strong adhesive layer  355  is provided on the opposite side. The strong adhesive layer  355  has adhesive power stronger than the weak adhesive layer  354  so that the strong adhesive layer  355  maintains a state of being wound around the rotating roller  351 . Perforations  356  are formed at predetermined length intervals on the adhesive component  352 . 
       FIG. 9A  and  FIG. 9B  illustrate a process of removing the adhesive component  352  when the adhesive power has weakened. When a user feels that the adhesive power has weakened, the user removes the most outer surface of the adhesive component  352  by one round to expose a new portion of the weak adhesive layer  354  of the adhesive component  352  as shown in  FIG. 9A . Then, the portion, the adhesive power of which has weakened, can be cut along the perforation  356 . At the time of cutting, if a portion thereof temporarily peels off as shown in  FIG. 9B , the user puts the portion back. Thus, a new portion of the weak adhesive layer  354  is exposed, so that the page-turning operation can be appropriately resumed. 
     As shown in  FIG. 1  to  FIG. 3 , the blower  5  is disposed upstream from the departure position of the book B. For example, when the page P of the book B is turned from left to right, the blower  5  is disposed on the left side of the page P which is placed at the departure position of the book B. When the page P of the book B is turned from right to left, the blower  5  is disposed on the right side of the page P which is placed at the departure position of the book B. Therefore the blower  5  is disposed outside the angle of view of the camera  22 . The blower  5  includes a blower body  52  and a blower base  53  which supports the blower body  52 . The blower body  52  includes an air outlet  51  which sends out air. 
     The blower body  52  is provided with a fan unit  54  (see  FIG. 10 ) and a wind-direction control unit  55  (see  FIG. 10 ). The fan unit  54  sends air from the air outlet  51 . The wind-direction control unit  55  changes a moving direction of air (a wind direction) sent from the fan unit  54 . The wind-direction control unit  55  changes the wind direction such that the wind blows upward or downward (the direction of the arrow Y 2  in  FIG. 3 ) from the air outlet  51 . 
     The blower base  53  supports the blower body  52  at a predetermined height. This blower base  53  is configured such that the air outlet  51  is disposed higher than the page P at the departure position. Therefore a wind which blows from the air outlet  51  passes above the page P at the departure position and blows against the page P at the destination position. The page P at the departure position is not much affected by the wind, while the page P at the destination position is much affected by the wind. 
     Next, the main control configuration of a document camera system  1  according to the embodiment will be explained.  FIG. 10  is a block diagram showing the main control configuration of the document camera system  1 . As shown in  FIG. 10 , the control unit  36  of the page-turning device  3  includes: a motor driver  361  which drives the first drive unit  33 ; a motor driver  362  which drives the second drive unit  37 ; a motor driver  368  which drives the fan unit  54 ; a motor driver  369  which drives the wind-direction adjustment unit  55 ; a ROM  363  where a variety of programs are stored; a RAM  364  where the programs stored in the ROM  363  are opened when the programs are executed; an operation unit  365  where a variety of instructions are inputted; a CPU  366  which controls the motor drivers  361  and  362  by opening and executing the programs, which are stored in the ROM  363 , in the RAM  364  on the basis of the instructions from the operation unit  365 ; an I/F  367  to which the computer  4  is connected; and a power source  370 . 
     The operation unit  365  includes a start switch  365   a  for starting page-turning processing and a stop switch  365   b  for stopping the page-turning processing. The CPU  366  counts turned pages as a value N from the time when the start switch  365   a  is operated to the time when the stop switch  365   b  is operated. The value N is stored in the RAM  364 . Thus the control unit  36  functions as a page-turn-amount detector of the present invention which detects the amount of the pages P turned by the turning unit  30 . 
     The page-turning processing by the document camera system  1  will be explained hereinafter.  FIG. 11  is a flowchart of the page-turning processing. 
     First, preparation before execution of the page-turning processing will be explained. In the page-turning device  3 , the position of the arm part  34  is adjusted such that the sticking part  35  is disposed at the starting point (the end point of the homeward movement) in advance. At the time, a user checks the adhesive power of the adhesive component  352 . If the adhesive power is weak, the user removes the weak portion to expose a new portion of the adhesive component  352 . Then, the user opens the book B such that one page (one double-page spread) P before a page (a double-page spread) P from which the user would like to start image pickup is exposed and moves the sticking part  35  to the end point of the outward movement (the start point of the homeward movement). When the power source of the page-turning device  3  is turned on, the CPU  366  opens in the RAM  364  a program for the page-turning processing stored in the ROM  363  to execute the program. 
     As shown in  FIG. 11 , at Step S 1 , the CPU  366  determines whether or not the start switch  365   a  is operated. When determining that the start switch  365   a  is not operated, the CPU  366  keeps the state as it is. When determining that the start switch  365   a  is operated, the CPU  366  shifts the processing to Step S 2 . 
     At Step S 2 , the CPU  366  resets the value N, which is stored in the RAM  364 , at zero. 
     At Step S 3 , the CPU  366  drives the fan unit  54  to carry out blowing with the blower  5 . At this time, an air volume of the fan unit  54  is set at an initial air volume. In the beginning of turning pages P, a large number of pages P exist at the departure position, so the thickness of the pages P as a whole is large. Therefore the wind-direction adjustment unit is controlled such that a wind from the blower  5  blows in a direction slightly upward from a horizontal plane. 
     At Step S 4 , the CPU  366  controls the first drive unit  33  such that the arm part  34  moves from right to left (homeward movement). 
     At Step S 5 , the CPU  366  determines whether or not a driving time of the first drive unit  33  exceeds a first predetermined time. When determining that the driving time does not exceed the first predetermined time, the CPU  366  keeps driving the first drive unit  33 . When determining that the driving time exceeds the first predetermined time, the CPU  366  shifts the processing to Step S 6 . The first predetermined time is set at a time length enough for the arm part  34  to move from the start point to the end point of the homeward movement. 
     At Step S 6 , the CPU  366  stops the first drive unit  33 . Thereby, the sticking part  35  sticks to a page P on the left with rotation of the sticking part  35  stopped. 
     At Step S 7 , the CPU  366  controls the first drive unit  33  such that the arm part  34  moves from left to right (outward movement). 
     At Step S 8 , the CPU  366  determines whether or not a driving time of the first drive unit  33  exceeds a second predetermined time. When determining that the driving time does not exceed the second predetermined time, the CPU  366  keeps driving the first drive unit  33 . When determining that the driving time exceeds the second predetermined time, the CPU shifts the processing to Step S 9 . The second predetermined time is set at a time (time length) shorter than the first predetermined time. In particular, it is preferable that the second predetermined time period is set from a time for the arm part  34  to move from the start point to around the middle point of the outward movement to a time for the arm part  34  to move from the start point to almost the end point of the outward movement. 
     At Step S 9 , the CPU  366  controls the second drive unit  37  to rotate the sticking part  35  while continuing driving of the first drive unit  33 . This rotation changes the adhesive power of the sticking part  35  when the sticking part  35  separates from a page P, so that the sticking part  35  can reliably separate from the page P. As shown in  FIG. 12 , the arm part  34  rotates clockwise (arrow Y 1 ) in the outward movement. In order to improve the separation performance, it is preferable that the second drive unit  37  rotate the sticking part  35  in a direction opposite to the swing direction of the arm part  34 , i.e. counterclockwise. 
     At Step S 10 , the CPU  366  determines whether or not the driving time of the first drive unit  33  exceeds the first predetermined time. When determining that the driving time does not exceed the first predetermined time, the CPU  366  keeps driving the first drive unit  33  and the second drive unit  37 . When determining that the driving time exceeds the first predetermined time, the CPU  366  shifts the processing to Step S 11 . 
     At Step S 11 , the CPU  366  stops the first drive unit  33  and the second drive unit  37 . The sticking page P is separated from the sticking part  35  while the second drive unit  37  rotates. Thereby, the sticking part  35  is located at a position apart from the pages P of the destination position with no page P sticking thereto. The sticking part  35  and the arm part  34  at this position are outside the angle of view of the camera  22 . Thus the whole turning unit  30  is outside the angle of view of the camera  22 . (See  FIG. 2A .) 
       FIG. 13  illustrates drive timings of the first drive unit  33  and the second drive unit  37  in the page-turning operation for one page. 
     In the embodiment, a drive end timing when the second drive unit  37  stops coincides with a drive end timing when the first drive unit  33  stops. However, the drive end timing when the second drive unit  37  stops may be earlier than the drive end timing when the first drive unit  33  stops. 
     At Step S 12 , the CPU  366  outputs a signal which indicates completion of the page-turning processing to the computer  4 . 
     At Step S 13 , the computer  4  controls the camera  22  on the basis of the inputted signal which indicates completion of the page-turning operation so that the pages P opened at present (spread state) are imaged (image pickup). At the time, since the turning unit  30  and the blower  5  are outside the angle of view of the camera  22 , only the pages P opened at present are imaged. Picked-up image data generated by the camera  22  are numbered one by one (each imaging) and stored in a storage unit  41  of the computer  4 . 
     At Step S 13 , both of the pages P in a spread state at present may be imaged. However, preferably, imaging is executed as follows. First, only the pages P at the departure position which are not inclined, for example, odd pages are imaged. Next, even pages P are placed at the departure position, and only even pages are imaged. Then the images are arranged alternately so that pages line up in numerical order, and are integrated as a set of images obtained by scanning all pages. 
     At Step S 14 , the CPU  366  adds one to the value N and stores the result in the RAM  364 . 
     At Step S 15 , the CPU  366  determines whether or not the value N exceeds a first threshold. When determining that the value N exceeds the first threshold, the CPU  366  shifts the processing to Step S 16 . When determining that the value N does not exceed the first threshold, the CPU  366  shifts the processing to Step S 17 . When many pages P are piled up at the destination position, the pages P are likely to return to the departure position. Therefore the first threshold is set at such an amount of turned pages that a wind of the initial air volume can reliably push the pages P against the destination position. 
     At Step S 16 , the CPU  366  controls the fan unit  54  to make the air volume larger than the initial air volume. 
     At Step S 17 , the CPU  366  determines whether or not the value N exceeds a second threshold. When determining that the value N exceeds the second threshold, the CPU  366  shifts the processing to Step S 18 . When determining that the value N does not exceed the second threshold, the CPU  366  shifts the processing to Step S 19 . As many pages P are turned, the height of the pages P at the departure position as a whole gets lower, and the lower edge of the last turned page P at the destination position gets lower. Therefore the second threshold is set at such an amount of turned pages that a wind in the initial wind direction can reliably push the pages P against the destination position. 
     At Step S 18 , the CPU  366  controls the wind-direction adjustment unit  55  to make the wind direction downward as compared with the initial wind direction. 
     At Step S 19 , the CPU  366  determines whether or not the stop switch  365   b  is operated. When determining that the stop switch  365   b  is not operated, the CPU  366  shifts the processing to Step S 2 . When determining that the stop switch  365   b  is operated, the CPU  366  ends the page-turning processing. In this way, the page-turning operation and the image pickup operation are alternately carried out, and image pickup of desired pages P is completed. 
     As described above, according to the embodiment, the blower  5  sends air above the page P at the departure position to blow against the page P at the destination position. Therefore the page P at the departure position is not affected by a wind, while the page P at the destination position is pushed by the wind. Thus the page P is prevented from returning to the departure position from the destination position, and is reliably turned. 
     Further, the air outlet  51  of the blower  5  is placed higher than the page P at the departure position. Thereby, a wind blowing from the air outlet  51  can reliably pass above the page P at the departure position. Thus the page P at the departure position can be reliably prevented from being affected by the wind. 
     Further, due to the support base  6 , the destination position inclined angle between the page P at the destination position and a horizontal plane is larger than the departure position inclined angle between the page P at the departure position and the horizontal plane. Thereby, a wind which has passed above the page P at the departure position can easily blow against the page P at the destination position although the page-turning device  3  has a simple configuration. 
     Further, the destination position inclined angle is adjustable. Thereby, even if thicknesses of the books B are different from each other, the destination position inclined angle can be adjusted for each thickness such that the page P at the destination position can be effectively blown by the wind. 
     A restoring force of the page P to return to the departure position changes in accordance with the amount of pages at the destination position. However, since the air volume of the blower  5  is adjustable, the air volume can be adjusted in accordance with the amount of pages at the destination position. Therefore, a balance of an ability to prevent pages from returning, electricity and noise reduction (silent performance) can be appropriately adjusted. 
     Further, since the air volume of the blower  5  is adjusted on the basis of the amount of turned pages P, the air volume can be automatically adjusted to the most appropriate volume. 
     As the amount of the pages P at the destination position gets larger, the restoring force of the page P gets stronger. However, since the air volume after many pages have been turned is larger than the air volume after only a few pages have been turned, the pages P are reliably prevented from returning to the departure position even after the amount of pages P at the destination position has increased. 
     Further, the direction of a wind from the blower  5  is adjustable. Therefore, although the amount of pages P at the departure position is changeable, the wind direction can be adjusted so that a wind passes above the page P at the departure position to blow against the page P at the destination position. 
     Further, the wind direction of the blower  5  is adjusted on the basis of the amount of turned pages P (the value N). Thereby, the wind direction can be automatically adjusted to the most appropriate direction. 
     As the amount of the pages P at the destination position increases, the thickness of the pages P at the departure position decreases. However, the wind direction after many pages have been turned is made downward as compared with the wind direction after a few pages have been turned. Therefore the pages P are reliably prevented from returning even after the amount of turned pages (the value N) has changed. 
     Further, since the document camera system  1  with the camera  22  which images the pages P of the book B is provided with the page-turning device  3 , the pages P can be reliably imaged while the pages P are automatically turned. 
     Further, since the turning unit  30  and the blower  5  are outside the angle of view of the camera  22  when the camera  22  images the pages P, the turning unit  30  and the blower  5  are prevented from getting into the images, so that appropriate images can be obtained. 
     The invention is not limited to the above embodiment, and several modifications can be applied thereto appropriately. 
     In the above embodiment, the sticking part  35  has the adhesive component  352 , and the sticking part  35  sticks to a page P by the adhesive power of the adhesive component  352 . However, it is also possible that the sticking part  35  sticks to a page P by suction etc. In this case, for example, a communicating hole which communicates with an inner space of the sticking part  35  is formed on the circumference surface of the sticking part  35  so that the inner space of the sticking part  35  and a pump communicate with each other, and by driving the pump such that the inner space is under negative pressure, sucking power acts onto the communicating hole. 
     Thereby, the sticking part  35  can stick to a page P by the suction power. 
     Other than suction and adhesion, sticking by electrostatic attraction can be applied to the sticking part  35 . 
     In the above embodiment, the drive shaft  39  of the second drive unit  37  is disposed along a direction perpendicular to the longitudinal direction of the arm part  34 . However, as shown in  FIG. 14 , the second drive unit  37  may be disposed such that the drive shaft  39  is along the longitudinal direction of the arm part  34 . In this case, the rotation axis of the sticking part  35  is also along the longitudinal direction, so that the arm part  34 , the second drive unit  37  and the sticking part  35 , as a whole, can be compact. 
     In the above embodiment, the air volume is automatically switched between two levels according to whether or not the amount of turned pages P (the value N) is more than the first threshold. However, it is also possible to set a plurality of thresholds so that the air volume is gradually changed through more levels. 
     Further, it is also possible to switch the air volume by hand. For example,  FIG. 15  illustrates a circuit in a case where an air volume of the fan unit  54  of the blower  5  is switched. As shown in  FIG. 15 , the fan unit  54  is connected to a power source and the ground via two resistances R 1 , R 2 . A switch SW is connected to the resistance R 1  in parallel. When the power source is ON and the switch SW is OFF, a voltage which has passed through the resistance R 2  is applied to the fan unit  54 . On the other hand, when the switch SW is OFF, a voltage which has passed through the two resistances R 1 , R 2  is applied to the fan unit  54 . Thus the different voltages are applied to the fan unit  54  by turning the switch SW ON/OFF. Thereby, the air volume shifts between two levels (OFF: low speed, ON: high speed). 
     At Steps S 15  and S 16  shown in the flowchart of  FIG. 11 , the switch SW can be automatically closed or opened according to which one is larger between the value N and the first threshold. 
     It is also possible that the wind direction of the blower  5  is adjusted by hand. For example, the fan unit  54  includes movable fins for adjustment of the wind direction. The wind direction is adjusted by adjusting inclination of the fins by hand. 
     Further, it is also possible that the wind direction is gradually changed in accordance with the value N in the same manner as the air volume. 
     Sometimes the page P at the departure position rises due to resilience of the page P itself, etc. It is not appropriate to image the page P in this state since a twisted (distorted) image is picked up. In order to prevent the page P from rising, the wind may be directed somewhat downward as compared with the wind direction shown in  FIG. 3  so that a part of the wind blows the page P at the departure position (the page P to be imaged) from above. 
     Further, it is also possible that a position of the wind is adjusted by adjusting the height of the blower base  53 . 
     In the above embodiment, only one blower  5  is provided. However, it is also possible that a plurality of blowers  5  is provided. For example,  FIG. 16  is a perspective view schematically showing the configuration of a document camera system  1 A with two blowers  5 . As shown in  FIG. 16 , the document camera  2  is disposed between the two blowers  5 . This arrangement is preferable because the distance between the pages P on one side and the camera  22  is shortened when the pages P on only the side of the pages P of the opened book B is imaged. 
     In the above embodiment, the amount of pages P turned by the turning unit  30  is detected by counting turned pages P. However, it is also possible that a thickness sensor is provided. The thickness sensor measures the thickness of the pages P at the destination position and the pages P at the departure position. The control unit  36  calculates the amount of turned pages on the basis of a measured result of the thickness sensor. In this case, the thickness sensor and the control unit  36  function as a page-turn-amount detector of the present invention. 
     Though several embodiments of the present invention are illustrated, the scope of the invention is not limited to the above embodiments but includes the scope of claims attached below and the scope of their equivalents.