Abstract:
A page turning apparatus of a passbook printer, which detects a turning error or the like at the early stage of turning irrespective of the size and characteristics of passbooks and allows retry of turning in a short time. The apparatus includes: a passbook conveying path; a detecting device placed on the conveying path; storing means that stores a passbook holding position and a threshold value corresponding to a determined size; a page turning mechanism configured to buckle the paper of an turning target page and to turn the buckled paper at the passbook holding position; a buckling sensor that senses a buckling status; a conveying mechanism that can convey the passbook to a designated position on the conveying path; and control means configured to drive the conveying mechanism so that the passbook is conveyed to the passbook holding position, and drive the page turning mechanism to buckle the paper, wherein the control means, if the buckling status sensed by the buckling sensor indicates that the buckling extent does not reach over the threshold value within a predetermined time, determines that the buckling has failed and drives the conveying mechanism so that the passbook is conveyed from the passbook holding position to a revised position apart therefrom by a predetermined adjusting distance.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a technique of turning pages in passbook printing available printers (passbook printers), and more specifically, it relates to an apparatus, method, and control program for executing optimum page turning in the event of a turning error or multiple turning. 
       BACKGROUND ART 
       [0002]    Passbook printers which can print on notebooks such as passbooks have a built-in page turning apparatus which is a mechanism to automatically turn pages without involvement by the user. Specifically, when entries to a page in printing are finished and entries to the next page are necessary, the printers themselves execute automated page turning without ejecting passbooks. 
         [0003]    To execute the automated passbook page turning, a turning mechanism has been used in which a turning roller is first landed on (brought into contact with) a turning target page, that is, the latter of the spread pages of the passbook, and is then rotated to shift the paper by friction, thereby raising the paper between the landed position and the folding axis of the passbook (or the central fold) (this is referred to as buckling). Then, when a sensor or the like senses that the buckling of the paper has reached a predetermined level, the turning roller is further rotated to bounce the paper onto the turning roller, thereby placing it onto the first half of the spread pages. 
         [0004]    However, when various types passbooks of different sizes, particularly, different lengths from the folding axis to the opposed side of the spread pages (hereinafter, referred to as “passbook length”) are handled by the same turning mechanism, the turning behavior must be changed from one passbook to another. In other words, for passbook printers for use in countries in which the passbook length has a unified standard, page turning apparatuses can be optimized to the passbook length. However, a significant number of countries use passbooks of different lengths. Conventional passbook printers used in such countries must be optimized to some of the passbook lengths. Therefore, turning of the pages of passbooks of significantly different sizes is prone to cause troubles such as double turning or page folding. 
         [0005]    Referring to the accompanying drawings, the conventional technique will be described hereinbelow, wherein like reference numerals designate like or corresponding components throughout. 
         [0006]      FIG. 1  shows an example of the mechanism of a page turning apparatus  100  for use in conventional passbook printers. Page turning rollers (also referred to as turning rollers)  102  are fixed to a roller shaft  104  and are retained by arms  106 . At the time a passbook is conveyed from the left to the page turning apparatus  100 , the arms  106  are held substantially horizontal with pins  110  fixed to an actuating shaft  108 , and the turning rollers  102  are retracted upward from the path of the passbook. The passbook is conveyed to a predetermined “passbook holding position” through the path between a bed plate  112  and a guide plate  114 . A feed roller  116  that conveys the passbook also serves to fix the passbook to the position during page turning operation by the turning rollers  102 . 
         [0007]      FIG. 2  shows the page turning apparatus  100  of  FIG. 1 , as viewed from the side. The procedure of conventional page turning will be described with reference to  FIG. 1  and  FIGS. 2(   a ) to  2 ( e ). 
         [0008]    A passbook  202  is conveyed to a “passbook holding position”, that is, a position at which the almost center of the latter of the spread pages is directly under the turning rollers  102  (the position at which A=B holds in  FIG. 2(   a )) (see  FIG. 2(   a )). The actuating shaft  108  is rotated counterclockwise through an angle by the attraction of an external solenoid (not shown) to tilt the pins  110  at the corresponding angle, thereby removing the restriction of the arms  106 , so that the turning rollers  102  are pushed against the surface of the latter of the spread pages by the force of springs  118  (see  FIG. 2(   b )). The turning rollers  102 , which are slowly driven counterclockwise via a belt  120  by the power of an external motor, shift only the uppermost paper  212  of the latter page by friction to “buckle” it in an angular form. At that time, the guide plate  114  made of a lightweight material is raised with a shaft  204  as a pivot (fulcrum) by the swell of the paper  212 . The curved surface  206  on the pivot is detected by a reflective sensor  208  (see  FIG. 2(   c )). 
         [0009]    As the detection by the sensor  208  triggers the removal of the attraction of the external solenoid, the actuating shaft  108  returns to the initial position to retract the turning rollers  102  upward. The turning rollers  102  then rotate counterclockwise at high speed for a predetermined time to bounce the angled paper  212  in contact with the surface of the turning rollers  102  above the turning rollers  102  (see  FIG. 2(   d )). The paper  212 , when bounced, becomes substantially flat between the turning rollers  102  and the guide plate  114  (see  FIG. 2(   e )). Thereafter, as the passbook is conveyed to the left in  FIG. 2 , the bounced paper  212  is rolled under the turning rollers  102  to be placed on the first half of the spread pages. Thus, the turning operation is completed, and the guide plate  114  returns to the initial horizontal position by gravity (see  FIG. 2(   a )). 
         [0010]    To execute the above-described turning operation to different-length passbooks by the same mechanism, it is desirable that the paper to be buckled be swelled at the same angle, and that the “passbook holding position” be set so that the distance from the passbook folding axis  210  to the position to which the turning rollers  102  land is held constant (that is, B is fixed in  FIG. 2(   a )). However, for short passbooks, this setting reduces the distance from the lower end of the passbooks to the turning rollers  102  landing position. This causes the lower end of the object paper to pass through the contact point of the turning rollers  102  at the stage of generating the same angled shape, to swell also the next page by the turning rollers  102 . As a result, two sheets of paper are bounced above the turning rollers  102  to cause the problem of double turning. 
         [0011]    Therefore, passbooks have generally been conveyed with the “passbook holding position” fixed so that the distance from the lower end of the passbook to the turning rollers  102  landing position is fixed (that is, A is fixed in  FIG. 2(   a )) irrespective of the passbook length. However, with such a “passbook holding position”, the distance from the turning rollers  102  landing position to the folding axis  210  is in turn decreased. This makes the swell of buckled paper distorted and sharp as compared with that of standard-length passbooks to cause unsmooth bouncing, thus increasing troubles such as folds. Such troubles occur more frequently in passbooks made of limp paper (or soft paper). 
         [0012]    To address these problems, Japanese Unexamined Patent Application Publication No. 2000-318349 describes an apparatus for turning pages in such a manner as to automatically adjust the position of a passbook in the optimum passbook holding position corresponding to passbook length information obtained by a sensor. 
         [0013]    However, under this method, a page turning error or double (or multiple) turning cannot be recognized until page identification information such as printed page numbers is read by an optical page reader (OPR) after completion of the page turning process. In other words, in the event of a page turning error, the apparatus cannot move to a passbook-holding position adjusting process until the turning roller makes one rotation, then the passbook is conveyed to a position at which the page identification information can be read, and the information is read. This is not desirable because it takes much time. In the event of double turning, without a reverse turning mechanism, the passbook must be ejected, and the user must correct the page of the ejected passbook and insert it again, resulting in troublesome time-consuming work. This method is not useful for preventing a turning error or the like which is often caused directly by paper quality (the hardness or coefficient of friction of paper) and the property of the spread pages because it adjusts the passbook holding position in the event of a turning error or the like only with passbook length information. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides an apparatus, method, and control program for executing optimum page turning. More specifically, the present invention detects the occurrence of a page turning error or multiple turning in the early stage of turning operation irrespective of the size and characteristics of an inserted passbook and allow page turning to be retried in a short time without the involvement of the user. Another object of the invention is to provide a learning function to prevent a turning error and multiple turning irrespective of the size and characteristics of an inserted passbook. 
         [0015]    A first aspect of the present invention is directed to an apparatus equipped in a passbook printing available printer, for turning one of the pages of a passbook that is unfolded on both sides of the folding axis, and a method and control program for the same. The apparatus includes: (1) a conveying path through which the passbook is conveyed, (2) a detecting device placed in a position of the conveying path, for detecting the size of the pages of the passbook, (3) storing means for storing a passbook holding position on the conveying path corresponding to the size, and a threshold value corresponding to the size, (4) a page turning mechanism placed in the vicinity of the passbook holding position and configured to buckle the paper of a turning target page of the passbook conveyed to the passbook holding position and to turn the buckled paper about the folding axis until the paper is overlapped on the previous page of the turning target page, (5) a buckling sensor placed in the vicinity of the page turning mechanism, for sensing a buckling status for the paper, (6) a conveying mechanism for conveying with a position control and a driving control the passbook to a designated position on the conveying path, and (7) control means configured to drive the conveying mechanism so that the passbook passes through the detecting device, to recognize the passbook holding position corresponding to the size and the threshold value corresponding to the size by referencing the storing means, drive the conveying mechanism so that the passbook is conveyed to the passbook holding position, and drive the page turning mechanism so that it starts buckling of the paper, wherein the control means, if the buckling status sensed by the buckling sensor indicates that the buckling extent does not reach over the threshold value within a predetermined time, determines that the buckling has failed and drives the conveying mechanism so that the passbook is conveyed from the passbook holding position to a first revised position apart therefrom by a first adjusting distance. 
         [0016]    A second aspect of the present invention is directed to an apparatus equipped in a passbook printing available printer, for turning one of the pages of a passbook that is unfolded on both sides of the folding axis, and a method for the same. The apparatus includes: (1) a conveying path through which the passbook is conveyed, (2) a detecting device placed in a position of the conveying path, for detecting the size of the pages of the passbook and the identification of the passbook, (3) storing means for storing a passbook holding position on the conveying path corresponding to the size, a threshold value corresponding to the size, and an offset distance corresponding to the identification, (4) a page turning mechanism placed in the vicinity of the passbook holding position and configured to buckle the paper of a turning target page of the passbook conveyed to the passbook holding position and to turn the buckled paper about the folding axis until the paper is overlapped on the previous page of the turning target page, (5) a buckling sensor placed in the vicinity of the page turning mechanism, for sensing a buckling status for the paper, (6) a conveying mechanism for conveying with a position control and a driving control the passbook to a designated position on the conveying path, and (7) control means configured to drive the conveying mechanism so that the passbook passes through the detecting device, to recognize the passbook holding position corresponding to the size and the threshold value corresponding to the size by referencing the storing means, to recognize the offset distance corresponding to the detected identification by referencing the storing means, to drive the conveying mechanism so that the passbook is conveyed to an offset holding position apart from the passbook holding position by the offset distance, and to drive the page turning mechanism so that it starts buckling of the paper, wherein the control means, if the buckling status sensed by the buckling sensor indicates that the buckling extent does not reach over the threshold value within a predetermined time, determines that the buckling has failed and drives the conveying mechanism so that the passbook is conveyed from the passbook holding position to a first revised position apart therefrom by a first adjusting distance. 
         [0017]    A third aspect of the present invention is directed to an apparatus equipped in a passbook printing available printer, for turning one of the pages of a passbook that is unfolded on both sides of the folding axis, and a method for the same. The apparatus includes: (1) a conveying path through which the passbook is conveyed, (2) a detecting device placed in a position of the conveying path, for detecting the size of the pages of the passbook and the identification of the passbook, (3) storing means for storing a passbook holding position on the conveying path corresponding to the size, a threshold value corresponding to the size, and an offset distance corresponding to the identification, (4) a page turning mechanism placed in the vicinity of the passbook holding position and configured to buckle the paper of a turning target page of the passbook conveyed to the passbook holding position and to turn the buckled paper about the folding axis until the paper is overlapped on the previous page of the turning target page, (5) a buckling sensor placed in the vicinity of the page turning mechanism, for sensing a buckling status for the paper, (6) a conveying mechanism for conveying with a position control and a driving control the passbook to a designated position on the conveying path, (7) a multiple sheet sensor placed so as to sense the paper turning about the folding axis and configured to determine whether multiple papers including the paper are being turned, and (8) control means configured to drive the conveying mechanism so that the passbook passes through the detecting device, to recognize the passbook holding position corresponding to the size and the threshold value corresponding to the size by referencing the storing means, to recognize the offset distance corresponding to the detected identification by referencing the storing means, to drive the conveying mechanism so that the passbook is conveyed to an offset holding position apart from the passbook holding position by the offset distance, and to drive the page turning mechanism so that it starts buckling of the paper, wherein the control means, if the buckling status sensed by the buckling sensor indicates that the buckling extent does not reach over the threshold value within a predetermined time, determines that the buckling has failed and drives the conveying mechanism so that the passbook is conveyed from the passbook holding position to a first revised position apart therefrom by a first adjusting distance, and wherein if the multiple sheet sensor detects that the multiple papers are being turned, the control means drives the conveying mechanism so that the multiple papers return to the position before the buckling and that the passbook is conveyed to a second revised position apart from the passbook holding position by a second adjusting distance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    These and other aspects and features of the present invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings. 
           [0019]      FIG. 1  shows an example of a mechanism of a page turning apparatus for use in conventional passbook printers. 
           [0020]      FIG. 2  shows the operation of the conventional page turning apparatus of  FIG. 1 . 
           [0021]      FIG. 3  shows an example of a hardware configuration of a page turning apparatus of a passbook printer according to an embodiment of the present invention and a passbook printer equipped with the page turning apparatus. 
           [0022]      FIG. 4  shows the mechanism of turning the pages of a passbook according to a first embodiment of the invention. 
           [0023]      FIG. 5  is a flowchart for the turning operation of the first embodiment. 
           [0024]      FIG. 6  shows an example of a buckling sensor that can measure the angle of the guide plate raised by buckling. 
           [0025]      FIG. 7  shows the mechanism of turning the pages of a passbook according to a second embodiment of the invention. 
           [0026]      FIG. 8  is a flowchart of the turning operation of the second embodiment. 
           [0027]      FIG. 9  shows the mechanism of turning the pages of a passbook according to a third embodiment of the invention. 
           [0028]      FIG. 10  is a flowchart of the turning operation of the third embodiment. 
       
    
    
       [0029]    The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0030]      FIG. 3  depicts an example of a hardware configuration of a passbook printer page turning apparatus  302  according to an embodiment of the invention and a passbook printer  300  equipped with the page turning apparatus  302 . 
         [0031]    In this configuration, a memory  314  including a flash ROM  310  and a static random access memory (SRAM)  312  is connected to a common bus  308  that is connected to a processor  306  (also referred to a central processing unit (CPU) or a microprocessing unit (MPU)) that controls the entire operation of the passbook printer  300 . A control program for achieving the invention can be stored in the memory  314 . The control program can be either a combination of a real-time operating system (OS) for embedded systems such as Windows CE® and application software which operates under the real-time OS or program code for a single embedded system having no hierarchical structure. 
         [0032]    The memory  314  may have the function of storing a reference table for various settings used by the invention. That is, a given area of the memory  314  can be used as storing means such as a reference table or the like, to be described later. 
         [0033]    The common bus  308  also connects to various logic devices such as a sensor controller  320 , an operation panel controller  322 , a communication controller  324 , a mechanical-system controller  326 , and a turning controller  328  for controlling the turning of pages according to the invention. The controllers are equipped in one custom LSI  330 , while they may be equipped in different LSIs, divided into some LSIs, and/or equipped in different discrete circuits. 
         [0034]    The turning controller  328  connects to a turning mechanism  344  composed of various mechanisms for executing the page turning of the invention, such as a sensor system including a passbook sensor (passbook detector)  332 , a buckling sensor (buckling detector)  336 , and a multiple turning sensor (multiple-turning detector)  338  and a driving system including a turning roller (turning mechanism)  340  and a passbook transfer roller (conveying mechanism)  342 . The turning controller  328  transmits and receives signals to/from the mechanisms to control the function of the mechanisms. The turning controller  328  can function correctly according to a printer control program (or part of the control program) stored in the memory  314 . 
         [0035]    Thus, the page turning apparatus  302  of a passbook printer according to the invention comprises the turning mechanism  344 , the turning controller  328 , the control program (or part of the control program) stored in the memory  314 , and storing means stored in the memory  314 , such as a reference table. A method for turning pages of a passbook printer, according to the invention, is achieved by the page turning apparatus  302 . The control program for the page turning apparatus  302  to achieve the turning method is stored in the memory  314 . 
         [0036]    Referring to  FIGS. 4 and 5 , a first embodiment of the present invention with the above structure will be described. 
         [0037]      FIG. 4  shows the mechanism of turning the pages of a passbook according to the first embodiment as viewed from the side; and  FIG. 5  is a flowchart for the turning operation of the first embodiment. 
         [0038]    Before the start of a series of page turning processes, the optimum position to fix a passbook  402  (hereinafter, referred to as a “passbook holding position”) corresponding to the passbook length is set (stored) in a storing means in advance (PS 502 ). The “passbook length” denotes the distance from the upside of the latter of spread pages (or the passbook folding axis  410 ) to the opposing lower side. The passbook holding position corresponding to the passbook length can generally be set so that almost the center of the latter page is located directly under the turning rollers  340 , although it can be set at a different position. 
         [0039]    The passbook holding position can be set in such a manner that optimum passbook holding positions for different passbook lengths determined by experiment or the like are stored as a reference table in the memory  314  or a calculation rule to determine a passbook holding position from a passbook length (e.g., “about the center of the latter of spread pages”) can be incorporated in a control program. In PS 502 , a buckling determining threshold value corresponding to the passbook length is also set. 
         [0040]    Suppose that the passbook  402  is in the passbook printer and spread pages are being printed. The spread pages include two pages of the first half and the latter half. When the printing of the latter half is completed and the next page needs to be printed, the passbook printer issues a request to turn the page to the page turning apparatus of the printer. Thus, the passbook page turning process by the page turning apparatus is started in response to the reception of a turning request from the part of the passbook printer other than the page turning apparatus (PS 504 ). 
         [0041]    At that time, the passbook  402  is conveyed to the page turning apparatus, with the pages that have just now been printed spread. A passbook sensor  332  is placed in the passbook conveying path so as to determine the length of a conveyed passbook. The length of the inserted passbook  402  is determined by the passbook sensor  332  (PS 506 ). Various known types of passbook sensors can be used as the passbook sensor  332 . One example is an optical medium sensor (a combination of an LED and a phototransistor), which is placed on the passbook conveying path to calculate the passbook length from the number of pulses of a passbook conveying stepping motor from the time the upper end of the passbook is detected until the time the lower end is detected. 
         [0042]    Upon detection of the passbook length, the passbook conveying roller  342  conveys the passbook  402  to the passbook holding position that is set corresponding to the passbook length in PS 502  (see  FIG. 4(   a ), PS 508 ). In other words, the passbook  402  is conveyed to the passbook holding position (the position at which A=B holds in  FIG. 4(   a )) at which almost the center of the latter of the spread pages is located directly under the turning rollers  340 . 
         [0043]    After the passbook is fixed to the passbook holding position, the turning rollers  340  placed in the vicinity of the passbook holding position are pushed against the paper  412  of the latter half of the passbook  402  to be turned, and rotated counterclockwise in  FIG. 4  so that the buckling of the paper  412  is started by the friction of the roller surface of the paper  412  (see  FIG. 4(   b ), PS 510 ). 
         [0044]    Upon starting of the buckling of the paper  412 , a guide plate  414  is raised with a shaft  404  as a pivot (fulcrum) by the swell of the paper  412 . The tilt angle of the raised guide plate  414  is measured by the buckling sensor  336  placed in the vicinity of the turning roller  340 . It is determined whether the measured angle exceeds the buckling determining threshold value that is set corresponding to the passbook length in PS 502  within a predetermined time from the start of the buckling (BS 512 ).  FIG. 6  shows an example of the buckling sensor  336  that can measure the angle of the guide plate  414  raised by buckling. An encoder plate  602  is fixed to the guide plate  414  with spacers  604  therebetween, and can be rotated about a shaft  606 , thus monitoring the tilt angle of the guide plate  414  by the count of the encoder pulses sensed by a photo-interrupter sensor  608 . 
         [0045]    Table 1 is a reference table that shows illustrative buckling determining threshold values corresponding to passbook lengths, for the buckling sensor  336 . The reference table can be stored in the memory  314 . The reference table illustrates the relationship between passbook lengths, corresponding optimum tilt angles of the guide plate  414 , and the counts of corresponding encoder pulses. Specifically, when the count of the encoder pulses read by the buckling sensor  336  exceeds the buckling determining threshold value on the reference table, that is, the count of the encoder pulses corresponding to the determined passbook length in a predetermined time, it is determined that the buckling has succeeded; conversely, when the count has not exceeded the threshold value in a predetermined time, it is determined that a buckling error has occurred. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Optimum 
                 Count of 
               
               
                   
                 Tilt Angle of 
                 Corresponding 
               
               
                 Passbook Length 
                 Guide Plate 
                 Encoder Pulses 
               
               
                   
               
             
             
               
                  60 mm or more and below 69 mm 
                 30° 
                 5 
               
               
                  69 mm or more and below 72 mm 
                 32° 
                 6 
               
               
                 . 
                 . 
                 . 
               
               
                 . 
                 . 
                 . 
               
               
                 . 
                 . 
                 . 
               
               
                 111 mm or more and below 114 mm 
                 62° 
                 21  
               
               
                   
               
             
          
         
       
     
         [0046]    When it is determined in BS 512  that buckling has succeeded, the turning rollers  340  moves slightly upward apart from the spread surface of the passbook  402  in response to that, and rotate counterclockwise in  FIG. 4  at high speed for a predetermined time to bounce the angled paper  412  that has landed on the surface of the turning rollers  340  above the turning rollers  340  (see  FIG. 4(   c ), PS 514 ). 
         [0047]    The paper  412 , when bounced, becomes substantially flat between the turning rollers  340  and the guide plate  414 . Thereafter, the passbook  402  is conveyed to the left in  FIG. 4 , so that the bounced paper  412  is turned so as to be placed on the first half of the spread pages (the first half of the pages to be turned), and the turning operation is completed (PS 516 ). The guide plate  414  returns to the initial horizontal position by gravity. 
         [0048]    Thus, the turning operation has successfully been completed and as such the passbook  402  is conveyed to the position to print the turned new page (PS 518 ). 
         [0049]    On the other hand, when it is determined in BS 512  that buckling has failed, that is, the count of the encoder pulses has not exceeded the buckling determining threshold value within a predetermined time, the buckling error must have occurred because the turning rollers  340  have landed too close to the passbook folding axis  410 . Therefore, the turning rollers  340  need to be moved a little apart from the folding axis  410  and then execute buckling again. In this case, the passbook  402  is conveyed so that the folding axis  410  becomes a first adjusting distance C apart from the present roller landing position (see  FIG. 4(   c ), PS 520 ). 
         [0050]    The buckling of the paper  412  is started again with the conveyed position as a new passbook holding position (PS 510 ). 
         [0051]    When it is determined in BS 512  that the buckling has failed, and the count of the failures has exceeded a predetermined maximum number, then it is determined that the buckling error cannot be corrected by the adjustment of the passbook holding position in PS 518  because of some other factors, and the adjustment of the passbook holding position is abandoned. Thus, the process step of ejecting the passbook from the printer and displaying an error message on an operation panel may be added (BS 522  and PS 524 ). 
         [0052]    Referring to  FIGS. 7 and 8 , a second embodiment of the present invention will be described.  FIG. 7  shows the mechanism of turning the pages of a passbook according to the second embodiment as viewed from the side; and  FIG. 8  shows the flow of the turning operation of the second embodiment. 
         [0053]    As in the first embodiment, a passbook holding position and a buckling determining threshold value corresponding to the passbook length are set in advance before the start of a series of page turning processes (PS 802 ). Furthermore, an offset distance D of the passbook holding position corresponding to the passbook ID and the page number of the passbook is set in advance (PS 803 ). The offset distance refers to an offset value not for conveying the passbook to a passbook holding position corresponding to the passbook length with reference to the passbook holding position, but for conveying the passbook to a position offset therefrom (corrected). The offset includes an offset in the direction in which the folding axis moves away from the turning-roller landing position and an offset in the direction in which the folding axis comes close to the landing position. Thus, it is desirable to set the offset distance as a value with a positive or negative sign. For example, an offset distance for offsetting the passbook apart from the landing position is set as a positive value. 
         [0054]    A buckling error, or particularly, double turning tends to occur during a turning operation, depending on the type and a specific page of the passbook. Thus, an offset distance suitable for such tendency is preset. 
         [0055]    Table 2 illustrates examples of the correlation between the types of passbook (passbook ID) and specific pages of the passbook, the characteristics, tendency during turning, and offset distances set in view of them. The table shows that the passbook of passbook ID 001 tends to cause double turning of all the pages because of larger friction between papers than normal ones, and thus an offset distance of −10 mm is set so that the turning rollers are landed to a position 10 mm closer to the folding axis than normal ones. For the passbook of passbook ID 002, the hardness of all the pages is lower (softer) than normal ones, so that it easily buckles, and thus double turning is prone to occur. Therefore, an offset distance of −7 mm is set. 
         [0056]    For the passbook of passbook ID 003, the binding is not so tight that the central pages tend to open (there is a clearance between central pages even if closed). Thus, turning of two pages before the central spread pages (that is, four pages before the latter of the central pages) tends to be double turning to spread the central pages. Thus, the offset distance is set to −12 mm. 
         [0057]    For the passbook of passbook ID 004, all the pages have lower friction than normal ones, causing little buckling. Thus, the offset distance is set to +10 mm so that the turning rollers land to a position 10 mm more apart from the folding axis than normal ones. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Pass- 
                   
                   
                   
                   
               
               
                 book 
                   
                 Characteristics of 
                 Tendency 
                 Offset 
               
               
                 ID 
                 Passbook Page 
                 Passbook/Paper 
                 during Turning 
                 Distance 
               
               
                   
               
             
             
               
                 001 
                 All pages 
                 High friction 
                 Tendency to 
                 −10 mm 
               
               
                   
                   
                 between papers 
                 cause double 
               
               
                   
                   
                   
                 turning 
               
               
                 002 
                 All pages 
                 Low hardness of 
                 Tendency to 
                  −7 mm 
               
               
                   
                   
                 paper 
                 cause double 
               
               
                   
                   
                   
                 turning 
               
               
                 003 
                 Four pages 
                 Binding Is Not so 
                 Tendency to 
                 −12 mm 
               
               
                   
                 before the latter 
                 Tight that central 
                 cause double 
               
               
                   
                 of central pages 
                 pages tend to open 
                 turning 
               
               
                 004 
                 All pages 
                 Low friction 
                 Tendency to 
                 +10 mm 
               
               
                   
                   
                 between 
                 cause buckling 
               
               
                   
                   
                 papers 
                 error 
               
               
                 . 
                 . 
                 . 
                 . 
                 . 
               
               
                 . 
                 . 
                 . 
                 . 
                 . 
               
               
                 . 
                 . 
                 . 
                 . 
                 . 
               
               
                   
               
             
          
         
       
     
         [0058]    Upon reception of a turning request from the part of the passbook printer other than the page turning apparatus, the page turning apparatus starts turning of pages in response to that (PS 804 ). 
         [0059]    First, the passbook sensor determines the length of a passbook  702  (PS 806 ), and then determines the passbook ID and the numbers of the present spread pages (PS 807 ). 
         [0060]    Then, the passbook conveying roller  342  conveys the passbook  702  to the position offset from the passbook holding position by the offset distance D with reference to the passbook holding position preset in PS 802  corresponding to the determined passbook length and the offset distance D preset in PS 803  corresponding to the determined passbook ID (see  FIG. 7(   a ), PS 808 ). 
         [0061]    After the passbook  702  is fixed to the conveyed position, the turning rollers  340  are pushed against the paper  712  of the latter of the spread pages, and are rotated counterclockwise in  FIG. 7  to start the buckling of the paper  712  by the friction between the turning rollers  340  and the paper  712  (see  FIG. 7(   b ), PS 810 ). 
         [0062]    It is determined by the buckling sensor  336  whether the buckling of the paper  712  has succeeded (BS 812 ), wherein when it is determined that the buckling has succeeded, the paper  712  is bounced above the turning rollers  340  (PS 814 ), and is then placed onto the first half of the spread pages. The turning operation is thus completed (PS 816 ). Upon completion of the turning, the passbook  702  is conveyed to the position to print the new page (PS 818 ). This is the same as the first embodiment. 
         [0063]    When it is determined that the buckling of the paper  712  has failed, the passbook  702  is conveyed from the present turning rollers  340  landing position to the position apart from the passbook folding axis by a first adjustment distance C (see  FIG. 7(   c ), PS 820 ). Then the buckling of the turning target page is started again, with the conveyed position as a new passbook holding position (PS 810 ). 
         [0064]    The failure of the buckling may be caused by the incorrect offset distance that is preset in PS 803  and used in PS 808 . Therefore, it is desirable to update the offset distance set in PS 803  so that when the same type of passbook is inserted into the page turning apparatus, the new passbook is offset directly to the new passbook holding position. The updating step may be provided around the step PS 820  (PS 826 ). 
         [0065]    Referring to  FIGS. 9 and 10 , a third embodiment of the present invention will be described.  FIG. 9  shows the system of turning the pages of a passbook according to the third embodiment as viewed from the side; and  FIG. 10  shows the flow of the turning operation of the third embodiment. 
         [0066]    A passbook holding position and so on corresponding to the passbook length are set in advance before the start of a series of page turning processes (PS 1002  and PS 1003 ). A turning operation is started in response to a turning request (PS 1004 ). A passbook sensor determines the length of the passbook and so on (PS 1006  and PS 1007 ). Then, the passbook  902  is conveyed to the position offset from the passbook holding position by the offset distance (PS 1008 ), at which buckling is started by the rotation of the turning rollers  340  (PS 1010 ), and it is determined whether the buckling has succeeded (BS 1012 ). Those steps are the same as those of the second embodiment. 
         [0067]    The processes in case of failure of the buckling (PS 1020  and PS 1026 , BS 1022 , and PS 1024 ) are also the same as those of the second embodiment. 
         [0068]    When it is determined in BS 1012  that the buckling has succeeded, the turning rollers  340  are moved slightly upward apart from the spread pages of the passbook  902  in response to that, and are rotated counterclockwise in  FIG. 9  at high speed for a predetermined time to bounce the angled paper  912  that has landed on the surface of the turning rollers  340  above the turning roller  340  (PS 1014 ). When the passbook  902  whose paper  912  is bounced is conveyed to the left in  FIG. 9 , the paper  912  becomes substantially perpendicular to the spread surface (see  FIG. 9(   a )). This timing, that is, the timing at which the folding axis  910  of the passbook  902  comes almost directly under the right outer circumference of the turning rollers  340  can easily be determined by the conveying roller  342  which controls the conveyance. 
         [0069]    At normal buckling, only one object paper is bounced perpendicularly; however, when two or more papers have been buckled, the two or more papers are sometimes bounced. Therefore, the apparatus has a multiplex sensor  338  including an LED  930  of a transmissive sensor (or a sound transmitter of an ultrasound sensor) on one side of the bounced paper and a phototransistor  932  of a transmissive sensor (or a sound receiver of an ultrasound sensor) on the other side, with which it is determined whether two or more papers have been bounced after the success of buckling (BS 1030 ). 
         [0070]    When it is determined in BS 1030  that two or more papers have been bounced, the passbook  902  is conveyed to the right in  FIG. 9 . This movement causes the bounced two or more papers to be held by the guide plate  414  into the state before buckling (see  FIG. 9(   b ), PS 1032 ). 
         [0071]    Such buckling and bouncing of two or more papers may be caused by the excessively long distance of the turning rollers  340  landing position from the passbook folding axis. This requires moving the turning rollers  340  landing position a little closer to the folding axis, and executing buckling again. Thus, in this case, the passbook  902  is conveyed so that the present turning rollers  340  landing position comes close to the passbook folding axis by a second adjusting distance (PS 1034 ). 
         [0072]    Then, the buckling of the turning target page is started to execute turning again, with the conveyed position as a new passbook holding position (PS 1010 ). 
         [0073]    As for a buckling error, the updating of the offset distance set in PS 1003  may be provided around PS 1034  (PS 1026 ). 
         [0074]    When it is determined in BS 1030  that two or more papers have been bounced, and the count of the bouncing has exceeded a predetermined maximum number, then it is determined that the buckling of two or more papers cannot be corrected by the adjustment of the passbook holding position in PS 1034  because of some other factors, and the adjustment of the passbook holding position is abandoned. Thus the process step of ejecting the passbook from the printer and displaying an error message on an operation panel may be added (BS 1036  and PS 1024 ). 
         [0075]    When it is determined in BS 1030  that only one paper has been bounced, it indicates that normal buckling and bouncing have been performed. Therefore, the passbook  902  is conveyed to the left in  FIG. 9(   a ) so that the bounced paper  912  is placed on the first half of the spread pages, and the turning operation is completed (PS 1016 ). Then the passbook  902  is conveyed to the position to print a new page (PS 1018 ). 
         [0076]    The foregoing description of the embodiments of this invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible.