Patent Publication Number: US-7584949-B2

Title: Bookbinding system, image forming apparatus, and bookbinding apparatus

Description:
This application is based on Japanese Patent Application No. 2005-232893 filed on Aug. 11, 2005 and No. 2006-076262 filed on Mar. 20, 2006 in Japanese Patent Office, the entire content of which is hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to bookbinding systems, image forming apparatuses, and bookbinding apparatuses that prepare booklets of bundles of sheets on which image forming has been carried out, wherein the bundles of sheets are covered with cover sheets on which images have been recorded by an image recording device. 
   In general, a sheet on which an image is recorded by a main body of an image forming apparatus such as a copying machine, a facsimile machine, a printer or a multifunctional machine including functions of the preceding machines is processed in many ways such as, for example, punching holes, stapling, saddle stitching, center folding, attaching a cover, folding, stamping or pasting and bookbinding, as post-processing. 
   Further, the title of the book or the like is commonly printed on the cover sheet of the bound book in order to clearly indicate the content of the book, and it is widely known to bind the printed cover sheet along with the bundle of sheets by punching holes and passing a spiral ring or the like through the holes, or to bind by stapling with staples, or to bind by applying a paste. 
   In Patent Document 1, a bookbinding apparatus has been disclosed that is provided with a printing section for printing on the spine portion of cover sheet bonded to the bundle of sheets, and for restricting the character sizes that can be printed according to the thickness of the bundle of sheets. 
   Further, in Patent Document 2, in an image forming apparatus provided with a bookbinding apparatus, a bookbinding apparatus has been disclosed that is provided with a section for trimming and adjusting the length of the sheets by detecting the sheet size, the sheet thickness and the number of sheets beforehand. 
   However, in the case of the apparatus described in Patent Document 1, the width of the cover on the spine portion has been determined beforehand. Therefore the apparatus is not one which trims an edge part of the cover sheet in the width direction of the cover sheet on the spine portion according to the thickness of the bundle of sheets and further is not one which properly adjusts the location of printing in the width direction with respect to the cover sheet on the spine portion. 
   Further, in the bookbinding apparatus of Patent Document 2, although description has been given about the device that cuts to adjust the length of the cover sheet, no description has been given of the device for recording images on the cover sheet. 
   Patent Document 1: Non-examined Japanese Patent Publication No. Hei 8-85275 
   Patent Document 2: Non-examined Japanese Patent Publication No. 2004-209869 
   SUMMARY 
   The present invention is as follows: 
   (1) A bookbinding system with the feature that it has an image recording device that records images on a cover sheet, a trimming device that cuts the edge part of said cover sheet that enwraps a bundle of sheets made up of a plurality of sheets based on the thickness information of said bundle of sheets, a binding device that binds said bundle of sheets after wrapping it with said cover sheet, and a control device that controls the recording position of images on said cover sheet recorded by said image recording device based on said thickness information of said bundle of sheets. 
   (2) An image forming apparatus with the feature that it is an image forming apparatus to which a bookbinding apparatus can be attached, and which includes a cover sheet storage section that can store cover sheets that enwrap bundles of sheets using the bookbinding apparatus, and a control device that controls the recording position of images on said cover sheet based on said thickness information of said bundle of sheets. 
   (3) A bookbinding apparatus that can be attached to an image forming apparatus, with the feature that said bookbinding apparatus includes a sheet bundle thickness detection device that detects the thickness of the bundle of sheets, a trimming device that cuts the edge part of a cover sheet that enwraps said bundle of sheets based on the result of detection by said sheet bundle thickness detection device, a binding device that binds said bundle of sheets after wrapping it with said cover sheet, and a transmission device that transmits the thickness information of said bundle of sheets based on the result of detection by said sheet bundle thickness detection device to said image forming apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an overall configuration diagram of an image forming system provided with an image forming apparatus and a pasting and bookbinding apparatus. 
       FIG. 2  is a cross-sectional view diagram of a pasting and bookbinding apparatus. 
       FIG. 3  shows the process of coating an adhesive while holding a bundle of sheets Sa in the vertical position in the collection section. 
       FIG. 4  shows the adhesive coating process. 
       FIG. 5  is an outline cross-sectional view diagram related to the cover sheet supporting section that supports the cover sheet. 
       FIG. 6(   a ) is the top view diagram of the cover sheet supporting section, and  FIG. 6(   b ) is the cross-sectional view diagram at the cross-section C-C in  FIG. 6(   a ). 
       FIG. 7  is a diagram showing that the pressing on the cover sheet S 2  by cover sheet pressing member is being released after the cover sheet S 2  is joined. 
       FIG. 8  shows the book S 3  being dropped onto belt  98 A and  98 B and discharged. 
       FIG. 9  is a flow chart of the bookbinding system according to the present invention. 
       FIG. 10  is a flow chart of the bookbinding system according to the present invention. 
       FIG. 11  is a flow chart of the bookbinding system according to the present invention. 
       FIG. 12  is a flow chart of the bookbinding system according to the present invention. 
       FIG. 13  is a diagram showing the cover sheet sizes and the ranges of the printing position. 
       FIG. 14  is an outline cross-sectional view diagram of an image forming system provided with an image forming apparatus and a stapling-bookbinding apparatus. 
       FIG. 15(   a ) is a diagram showing square spine formation and  FIG. 15(   b ) is a perspective view diagram showing a booklet joined with a cover sheet, on which a square spine has been formed and which is being stapled using staples by the stapling device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Next, a bookbinding apparatus, an image forming apparatus and a bookbinding system of the invention will be explained as follows, referring to the drawings. 
   &lt;Image Forming Apparatus A&gt; 
     FIG. 1  is an entire structure diagram of a bookbinding system equipped with an image forming apparatus A and a bookbinding apparatus B. 
   Image forming apparatus A has an image recording device in which rotary image carrier  1 , charging unit  2 , image exposure unit  3 , developing unit  4 , transfer unit  5 A, neutralizing unit  5 SB and cleaning unit  6  are arranged around rotary image carrier  1  in an image forming apparatus main body. In the image recording device, exposure scanning based on image data obtained from a document through reading by a laser beam of the image exposure unit  3  is conducted after a surface of the image carrier  1  is charged evenly by the charging unit  2 , to form a latent image, and the latent image is developed reversely by the developing unit  4 , and a toner image is formed on a surface of the image carrier  1 . The image data can be image information made in and received from image data generating device such as a personal computer PC as an exterior apparatus. 
   Further, in the following descriptions, the constitutive sheets are denoted by S 1 , the bundle of sheets is denoted by Sa, the sheet for the cover sheet is denoted by S 2 , and the booklet formed by joining the bundle of sheets and the cover sheet is denoted by S 3 . In addition, the cover sheet S 2  may be indicated as the cover sheet S 2 A on which images have been printed by the image forming apparatus, while distinguishing it from the cover sheet S 2 B which is the cover sheet that is stored inside the bookbinding apparatus. 
   The sheet storing section is provided with sheet storing section  7 A storing sheet S 1  and cover sheet storing section  7 F capable of storing cover sheet S 2  and sheet S 1  fed from sheet storing section  7 A is transported to a transfer position. In the transfer position, the toner image stated above is transferred onto sheet S 1  by the transfer unit  5 A. After that, charges on the reverse side of the sheet S 1  is eliminated by the neutralizing unit  5 B and the sheet S 1  is separated from the image carrier  1  to be transported by transportation section  7 B, and then, is heated and fixed by fixing unit  8  to be ejected from sheet ejection roller  7 C. 
   When forming images on both sides of sheet S 1 , sheet S 1  subjected to heating and fixing by fixing unit  8  is diverted from an ordinary sheet ejection path by transportation path changeover plate  7 D, then, is reversed upside down through a movement in a form of a switchback in reversing transportation section  7 E, and passes the image forming section again so that an image is formed on the back of sheet S 1 , and is ejected out of the apparatus from sheet ejection roller  7 C through fixing unit  8 . Sheet S 1  ejected from the sheet ejection roller  7 C is fed into bookbinding apparatus B. 
   In addition, when carrying out image formation on the cover sheet S 2  in the image forming apparatus A, the cover sheet S 2  that is heat fixed by the fixing section  8  is diverted from the normal sheet discharge path by the transportation path changeover plate  7 D, and at the point of time when the trailing edge of the cover sheet S 2  has passed over the branching point, the direction of rotation of the respective transporting rollers gripping the cover sheet S 2  is changed and the leading and trailing edges are reversed and transported towards the sheet discharge roller  7 C, and the cover sheet is discharged to the outside of the equipment by the discharge roller  7 C. 
   The document feeder A 2  conveys the document one sheet at a time to the reading position. The image reading section A 3  reads out the images in the document that has been transported by the document feeder A 2  or in the document placed on the document table  9 , and generates image signals. The communication section A 4  carries out communication with the network equipment, and generates the image signals as the image information upon receiving the image formation command transmitted from the network. 
   With respect to the surface of image carrier  1  after image processing, developing agents remaining on the surface are removed by cleaning device  6  so that the image carrier  1  turns out to be ready for the succeeding image forming. 
   Next, although a bookbinding apparatus according to the present invention is described as a first preferred embodiment based on a pasting and bookbinding apparatus B that uses paste as the bookbinding medium, the present invention shall not be restricted to the preferred embodiments given hereunder. 
   &lt;Bookbinding Apparatus B&gt; 
     FIG. 2  is an outline front cross-sectional view diagram of the bookbinding apparatus B. 
   The bookbinding apparatus B has a conveying section  10  that conveys the sheet S 1  discharged from the image forming apparatus A to the sheet discharge tray  20  or to the sheet inverting section  40 , a collection section  50  that collects the sheets S 1  sent one sheet at a time from the sheet inverting section  40 , a coating device  60 , a cover sheet storage section  80  as a second cover sheet storage section that stores the sheets S 2 B, sheet feeding rollers  83  that feed the cover sheets S 2 B, a cutter  81  as a trimming device that trims the cover sheets S 2  to a length corresponding to the bundle of sheets S 1 , a cover sheet supporting section  90  that supports the cover sheets, and a book discharging section  100 . 
   The changeover gate G 1  changes the transportation path of the sheet S 1  or the cover sheet S 2  discharged from the image forming apparatus A. 
   When the sheet discharged from the image forming apparatus A is a sheet S 1 , the sheet S 1  is sent to the transportation path  10  due to the selection of the changeover gate G 1 , and is either discharged to the sheet discharge tray  20  after passing through the discharge path  12 , or is transported to the sheet inverting section  40  depending on the selection of the changeover gate  11  provided in the transportation path  10 . When the bookbinding designation has not been made in the operation section or the like of the image forming apparatus A, the sheet S 1  is discharged to the sheet discharge tray  20 . 
   When the sheet discharged from the image forming apparatus A is a cover sheet S 2 A, the cover sheet S 2 A is sent to the transportation path H 1  due to the selection of the changeover gate G 1 . In addition, the cover sheet S 2 A passes through the cutter  81  to the cover sheet supporting section  90  through the changeover gate G 2  that selects between it and the cover sheet S 2 B sent from the cover sheet storage section  80 . 
   When the bookbinding designation has been made in the operation section or the like of the image forming apparatus A (this is called the bookbinding operation mode), the sheet S 1  is conveyed to the sheet inverting section  40  via the transportation path  13 , and after it is switched back in the sheet inverting section  40 , it is transported to the collection section  50 . In the collection section  50 , the sheets S 1  of the set number are accumulated, and once sheets of the set number have been accumulated in the collection section  50 , they are gripped and rotated, and the resultant bundle of sheets Sa made of sheets S 1  is held in the approximately vertical state. 
   An adhesive is coated by coating device  60  on the spine surface of the bundle of sheets Sa (the bottom end surface in  FIG. 2 ) held in the approximately vertical state in the collection section  50 . The cover sheet S 2  comes into contact with and gets adhered to the bundle of sheets Sa on which the adhesive has been coated thereby preparing the book S 3  to be discharged to the book discharging section  100 . 
   Detailed explanation is given about the respective sections of the bookbinding apparatus in the following. 
   The sheet S 1  conveyed through the transportation path  13  is discharged by the sheet discharging rollers  14  and transported by the swinging press contact rollers  401 . After the sheet S 1  rising on the inclined inverting tray  402 , the swinging press contact rollers  401  rotate in the opposite direction conveying the sheet S 1  in the downward direction. The sheet S 1  conveyed in the downward direction falls into and gets collected in the collection section  50 . 
   The sheet S 1  that has been conveyed in the downward direction in the sheet inverting section  40  is supported in the inclined state in the collection section  50  by the sheet supporting unit including a supporting plate  502  and a receiving plate  506 . 
   The sheets S 1  discharged successively from the image forming apparatus are collected in the collection section  50 , thereby forming a bundle of sheets Sa. The number of sheets S 1  constituting the sheet bundle Sa is recognized not only from the number of document sheets counted using the automatic document feeder A 2  mounted on the image forming apparatus or from the number of document sheets obtained from the original document image information transmitted via a personal computer or the like, but also from the number of document sheets inputted beforehand by the operator or the like. 
   The part designated by the number  504  is a member for suppressing the rising-up of the accumulated sheet S 1 , and gets separated and again comes into contact every time a sheet S 1  is fed to the collection section  50  thereby pressing the sheet S 1 . The part designated by the number  505  is an alignment plate that aligns the side edges of the sheets. 
   As soon as sheets S 1  of the set number is collected in the collection section  50 , a holding plate  503  is actuated thereby gripping and holding the sheet bundle Sa. 
   With the sheet bundle Sa in the gripped and held state, the collection section  50  rotates with the shaft  501  as the axis, and the sheet bundle Sa is changed from the inclined state to the vertical state. 
   &lt;Adhesive Coating Process&gt; 
     FIG. 3  shows the adhesive coating process while retaining the sheet bundle Sa in the collection section  50  in the vertical state. 
   Before describing the coating process, the supporting of the sheets by the holding plate  503  in  FIG. 3(   a ) is described below. 
   Before rotating the collection section  50  to the vertical state, the holding plate  503  moves due to the drive of the motor M 4 , and presses the sheet bundle Sa. By stopping after detecting that the driving torque for pressing has reached a prescribed value, the sheet bundle Sa is retained strongly by the supporting plate  502  and the holding plate  503 . The stopping position of the holding plate  503  is detected by the sensor  510  and the encoder  509 , and is stored in the storage device of the position detection device  511 . Because of this, it is possible to grasp the thickness of the sheet bundle Sa accumulated in the collection section  50  by actual measurement. The collection section  50  is rotated until it goes into the vertical state while strongly retaining the sheet bundle Sa by the supporting plate  502  and the holding plate  503  with the shaft  501  as the axis. 
   With the sheet bundle Sa in the retained state, the receiving plate  506  is rotated by 90 degrees thereby making it recede as shown in  FIG. 3(   b  ). 
   In the state of  FIG. 3(   c  ), the bottom surface SA of the sheet bundle Sa is separated from the coating roller  63 . 
   As is shown in  FIG. 3(   d  ), the coating device  60  in which a hot melt adhesive material  653  is stored rises up due to the drive of a motor M 2 , and the coating roller  63  touches the bottom surface SA of the sheet bundle Sa in the figure. The coating roller  63 , while being driven in a rotating manner by a motor M 1  via a chain  64  shown in  FIG. 2 , moves in a direction at right angles to the surface of the paper on which  FIG. 3  is illustrated, thereby coating the bottom surface of the sheet bundle Sa with the adhesive material  653 . 
   The coating process is described next referring to  FIG. 4 . 
   At the stage of starting the bookbinding in  FIG. 4(   a  ), the coating device  60  is at the right end position (the first position) which is its home position. This position is located at the deep end when viewed from the front of the bookbinding apparatus B shown in  FIG. 2 . In this right end position, solid adhesive material is replenished to the adhesive container via the replenishment path  66  because the door  64  becomes open. At the beginning of the bookbinding process, the coating device  60  moves from the home position towards the left in  FIG. 4(   a  ), the movement from this home position to the left end position (the second position) is carried out by the drive of a belt  67  (the second moving device) which is driven by a motor M 3 . The starting of the motor M 3  is conducted based on the signal of the detection of the passing of the leading edge of the last of the sheets S 1  constituting the sheet bundle Sa collected in the collection section  50 , transmitted from the sheet sensor SE which is provided immediately below and on the downstream side of the inverting tray  402  (see  FIG. 2) . While the coating device  60  is moving to the left end position, the coating roller  63  is separated from the bottom surface SA of the sheet bundle Sa. 
   Further in the stage of  FIG. 4(   b  ) in which the coating device  60  moves from the left end position towards the right end position, the coating roller  63  rises due to the drive of the motor M 2  and comes into contact with the bottom surface SA of the sheet bundle Sa thereby applying the adhesive material  653 . The timing of starting the coating process of  FIG. 4(   a  ) is controlled so that, when the sheet bundle Sa has been put in the vertical state in which it can be coated, the coating is started after waiting for the transportation of the cover sheet to stop after trimming by the cutter  81 . 
   Because of such timing control, the operations of respective parts are performed continuously and the bookbinding operation is conducted with a high efficiency. After the coating device  60  moves to the home position, the cover sheet S 2  is joined to the sheet bundle Sa. 
   &lt;Joining Process&gt; 
   Next, the process of joining the sheet bundle Sa and the cover sheet S 2  is explained below referring to  FIG. 5  to  FIG. 8 .  FIG. 5  is an outline cross-sectional view diagram related to the cover sheet supporting section  90  that supports the cover sheet. 
   The cover sheet S 2  can be either the cover sheet S 2 A that is discharged from the image forming apparatus A and stored in the cover sheet supporting section  90  due to the selection of the transportation path changeover gate G 1 , or is the cover sheet S 2 B stored in the sheet feeding tray  801  of the cover sheet storage section  80  provided at the bottom part of the bookbinding apparatus as shown in  FIG. 2 . 
   The cover sheet S 2 B is used when an already printed cover sheet is to be used or when it is necessary to use a cover sheet on which it is not necessary to print. Further, when the bookbinding apparatus B is provided with a second image recording section as is described later, this is also used when printing is done directly on the cover sheet S 2 B using the second image recording section. In addition, by using the cover sheet S 2 B, since image recording on sheets S 1  can be started without having to wait for the cover sheet S 2 A to be discharged from the image forming apparatus, there is the advantage compared to using the cover sheet S 2 A discharged by the image forming apparatus that the time taken for completion of bookbinding can be shortened and the productivity can be increased. 
   When the bookbinding apparatus B is provided with a second image recording unit  85  that records images on the cover sheets S 2 B, as is shown in  FIG. 2 , the second image recording unit  85  is placed in a transportation path from the cover sheet storage section  80  to the cover sheet supporting section  90 . The second image recording unit  85  has a recording section using an ink jet method of the line head shape, or a thermal recording device having a thermal head and ink ribbons or the like, and can print directly on the cover sheet S 2 B. 
   The cover sheet S 2 A or S 2 B, after being aligned and switched back in the cover sheet supporting section  90 , is cut to a length corresponding to the bundle of sheets S 1  by the cutter  81  as a cutting device, conveyed by the transporting rollers, and is placed in the horizontal condition on the cover sheet supporting unit  901  indicated by a single-dot and dash line. The cover sheet supporting unit  901  is constituted using a plurality of members such as the pressing members  91  and  92 , the cams  93  and  94  that drive the pressing members  91  and  92 . 
   Further, the cutter  81  cuts the edge part of the cover sheet S 2  to a length based on the information of the size of the cover sheet S 2 , the information of the size of sheets S 1 , and the information of the thickness of the sheet bundle Sa that is stored in the position detection device  511 . However, regarding the information of the thickness of the sheet bundle Sa, apart from using the information obtained by actual measurement, it is also possible to calculate by multiplying the number of sheets based on the count of the document sheets, or the number of sheets obtained from the image information received from an external equipment, or from the received image information that has been inputted in the operation section of the image forming apparatus, by the thickness per sheet of the sheets S 1  on which recording is to be made. The cutting shreds of the cover sheet S 2  after trimming are stored in the storage box  82 . 
   The cover sheet S 2  cut to a prescribed length is conveyed by transporting rollers and is inserted between a top guide plate  955  and a bottom guide plate  956  provided with a spacing of about 5 mm. The cover sheet S 2  is transported by the cover sheet transporting rollers  951  and the follower rollers  952  provided at the tips of the cover sheet pressing members  95  and  96 . The cover sheet S 2  is controlled so that it stops when it arrives at a prescribed position based on the size information of the cover sheet S 2 , and the information of the thickness of the bundle of sheets S 1 . 
     FIG. 6(   a  ) is the top view diagram of the cover sheet supporting unit  901 , and  FIG. 6(   b  ) is the cross-sectional view diagram at the cross-section C-C. 
   The belts  98 A and  98 B carry out a function of alignment operation of correcting the inclination of the cover sheet S 2  that has been conveyed, and an operation of conveying the book S 3  that has been bound, to the book discharging section  100 . 
   As a device for the alignment of the cover sheet S 2 , the aligning members  981 A and  981 B are provided, that carry out alignment of both end surfaces of the cover sheet S 2  in directions parallel to the direction of transportation, and drum-shaped rollers are provided on the aligning members  981 A and  981 B to extend the belts  98 A and  98 B. The aligning members  981 A and  981 B carry out the aligning operation every time a cover sheet S 2  is supplied. In addition, when the cover sheet supporting unit  901  to be described later rises, the aligning members  981 A and  981 B and the belts  98 A and  98 B recede to the position shown by two-dots and one dash line in  FIG. 6(   a  ). 
     FIG. 5(   b  ) is a diagram showing the cover sheet S 2  pressed by pressing members  95  and  96 , and being raised in that state along with the cover sheet supporting unit  901  due to the motor M that drives the belts  99 A and  99 B (see  FIG. 2) . 
   The cover sheet supporting unit  901  rises further by a few millimeters from the position shown in  FIG. 5(   b  ). This position after rising by a few millimeters is the position shown in  FIG. 5(   c  ). After rising, the pressing members  91  and  92  press the cover sheet S 2  from left and right, make corners at the boundary between the front cover sheet and the spine cover of the book, and at the boundary between the spine cover and the back cover sheet, and the book S 3  is formed by closely contacting the cover sheet S 2  with the sheet bundle Sa. The duration for which the pressing members  91  and  92  are pressing is about 5 seconds, and the pressing force is about 200 Nf. 
   Further, the movement in the lateral direction of the pressing members  91  and  92  is obtained from the cams  93  and  94  (see  FIG. 6 ) that are driven by motors (not shown in the figure). In addition, the device for the movement of the pressing members  91  and  92  can also have a configuration in which a rack is provided for, each member, so that the member can be moved by the rotation of a pinion that engages with the rack. 
   The processing of the cover sheet S 2  after it has been joined is explained below using  FIG. 7 . 
   When the cover sheet supporting unit  901  rises, the pressing members  95  and  96  are pressing the cover sheet S 2  from above and maintain the cover sheet S 2  in the flat state. A prescribed time period after the cover sheet S 2  rises, the pressure of the pressing members  95 ,  96 , and  97  is released due to the drive of a motor (not shown in the figure), and the state becomes that shown in  FIG. 7 . At this time, the cover sheet S 2  goes into the state in which it is being lifted up by the cover sheet pressing member  97  that has been positioned below the cover sheet S 2 . 
   When the joining of the cover sheet S 2  has been completed, the cover sheet supporting unit  901  that released the pressing members  91  and  92 , lowers by about 100 mm due to the drive of the belts  99 A and  99 B (see  FIG. 2 ) and returns to the home position. 
   At this time, in order to lift up the left and right sides of cover sheet S 2  by about 50 mm, the cover sheet pressing members  95 ,  96 , and  97  once go to the horizontal state from the vertical state, and then are again swung in the opposite direction. 
   Next, the belts  98 A and  98 B are moved so as to return to the position of narrower than the width of the cover sheet S 2 , and the cover sheet supporting unit  901  is raised by about 70 mm. 
   The holding plate  503  moves to the retracted position, so that the holding pressure is released. Because of this, the book S 3  made up of the bundle of sheets S 1  and the cover sheet S 2  falls on the belts  98 A and  98 B ( FIG. 8(   a  )). While lowering again the cover sheet supporting unit  901 , the belts  98 A and  98 B are rotated, and the book S 3  is conveyed toward the book discharging section  100  and is made to tumble there (see  FIG. 8(   b  )). At this time, the cover sheet supporting members  96  and  97  are swung to a large extent toward the upward direction, and the left side cover sheet is lifted up. As is shown in  FIG. 8(   c  ), the book S 3  is conveyed up to the left end by the belts  98 A and  98 B and is discharged, as it is, to the book discharging section  100 . 
   The book discharge table  101  is raised and lowered due to the drive of a belt, and the book discharge table  101  on which the book S 3  is placed is lowered, the book S 3  is transferred to the belt  102 , and the book S 3  is conveyed by the belt  102  and is discharged from the bookbinding apparatus. 
   &lt;Flow chart&gt; 
   Next the bookbinding system according to the present invention is described using the flow charts of  FIG. 9  to  FIG. 12 . Further, in these flow charts, the parts during which the image forming apparatus carries out warming up from the start and until the initial checks of the respective sections have been completed are omitted for the sake of simplicity. 
   In the present system, the information of the images of the cover sheet and the image of the respective sheets can not only be received via a communication section A 4  from a personal computer PC connected as an external equipment to the image forming apparatus A, but also can be obtained from the image reading section A 3 . In addition, when the image forming apparatus A itself can also have functions equivalent to that of a personal computer PC, and in the case of an apparatus in which images can be formed in the operation panel, the images formed on the operation panel can also be obtained as the image information. 
   Firstly, at the time of starting the preparation of the book S 3 , in Step  1 , a judgment is made as to whether the image information of the cover sheet S 2  has been received via the personal computer PC or has been received after the image information was prepared in the operation panel. The image information that is received can be only the image information of the front cover sheet, or else can also include other image information for the spine cover part or the image information of the back cover sheet. The operation jumps to Step  5  if the image information for the cover sheet S 2  either has been received via a PC or has been received after being prepared in the operation panel. However, if the image information for the cover sheet S 2  has not been received, the operation proceeds to Step  2 , wherein the image being read out by the image reading section A 3  of the image forming apparatus A is awaited. When the image for the cover sheet S 2  is read out by the image reading section A 3 , the operation proceeds to Step  3 , and a judgment is made as to whether the read out image is to be image-formed, as it is, in the cover sheet S 2 , or else, the image formation is to be done after changing the size of the read out image, or changing the recording position, or after carrying out some processing. (Step  4 ) When the judgment is made, the operation proceeds to Step  5 . 
   In Step  5 , a judgment is made as to whether or not the image information for each of the sheets S 1  has already been received via the PC or the like. If the image information has already been received, the operation proceeds to the point indicated by A in  FIG. 10  or to the point indicated by B in  FIG. 11 . If it is judged in Step  5  that the image information has not been received, the reading of the images of each of the sheets S 1  by the image reading section A 3  of the image forming apparatus A is awaited. When each of the images has been read out and the image information for each of the sheets S 1  has been obtained, the operation proceeds to A in  FIG. 10  or to B in  FIG. 11 . 
   Next, the operation proceeds to A in  FIG. 10  if the thickness information of the sheet bundle Sa is to be obtained by actual measurement. On the other hand, the operation proceeds to B in  FIG. 11  if the thickness information of the sheet bundle Sa is to be obtained by the multiplication of the number of sheets obtained from the image information for sheets S 1  received via the personal computer PC or the like, by the thickness of the thickness information per each sheet of the sheets S 1 . In addition, the operation proceeds to B in  FIG. 11  even when the thickness information of the sheet bundle Sa is to be obtained by the multiplication of the number of sheets obtained from the number of original document sheets counted by the document feeder A 2  of the image forming apparatus A by the thickness of the thickness information per each sheet of the sheets S 1 . 
   In the following, in order to simplify the explanations, the descriptions are given for the case when only one of the book S 3  is to be formed. 
   To begin with, description is given below for the case when the thickness information of the sheet bundle Sa is obtained by actual measurement. 
   After the Step  5  or the Step  6  of  FIG. 9 , the operation proceeds to Step  7  of  FIG. 10 , and the image formation for each of the sheets S 1  constituting the sheet bundle Sa is started. The image formation is repeated until the image formation for all the sheets S 1  has been completed (Step  8 ). When the image formation for all sheets S 1  has been completed and the all the sheets S 1  have been accumulated in the collection section  50  of the bookbinding apparatus B, the operation proceeds to Step  9  so that the motor M 4  moves the holding plate  503 , and the sheet bundle Sa is gripped by the supporting plate  502  and the holding plate  503  of the collection section  50 . As has been described earlier, the stopping position of the holding plate  503  is detected by the encoder  509 , and this information is stored in the storage device of the position detection device  511 . From this stopping position, the information of the thickness of the sheet bundle Sa can be obtained. 
   Next, the operation proceeds to Step  10 , the CPU of the image forming apparatus A, based on the stopping position stored in the storage device, computes the amount of trimming of the edge part of the cover sheet S 2  and the position of recording the image of the cover sheet S 2  after trimming it. At this time, in the case of an apparatus in which it is possible to select the size of the sheets S 1  constituting the book S 3  and the size of the cover sheet S 2 , the amount of trimming and the recording position are derived considering also the size information of the sheets S 1  and the size information of the cover sheet S 2 . 
   On the other hand, in the case of a system in which the size of the sheets S 1  that can be book-bound is limited to only one size and also cover sheet S 2  of only one pre-determined size can be used, it is not necessary to consider the size information of the sheets S 1  or the size information of the cover sheet S 2  at the time of computing the amount of trimming and the recording position. Although the image recording on the cover sheet S 2  is made before trimming its edge part, the recording positions of the images respectively on each of the areas of the front cover page, the spine cover part, and of the back cover page are shifted at the time of recording corresponding to the amount of trimming. 
   For example, in the case when equally spacing has been specified for the respective recording positions in each of the areas, at the time of recording the images, each image is recorded at a position that is shifted by an amount corresponding to the amount of trimming of the edge of the sheet from the position of the equally spacing of each area. In addition, for example, if in each area, the margin has been specified from the edge part of the area to the position of starting the image recording, the starting position of recording of each image will be the position shifted by a distance corresponding to the amount of trimming of the edge of the sheet from the margin part of that area. By shifting the recording position in this manner, the images can be recorded at the desired positions on the cover sheet S 2  irrespective of the thickness of the sheet bundle Sa. 
   When the positions of recording the images in the respective areas of the cover sheet S 2  have been obtained, the operation proceeds to Step  11 , and the images are recorded on the cover sheet S 2  in the image forming section of the image forming apparatus A.  FIG. 13  is a diagram showing, for the cover sheet S 2 , the printing positions of the images in the front cover sheet, the spine part of the cover sheet, and on the back cover sheet along with the trimming area of the edge part of the cover sheet S 2  determined based on the thickness information of the sheet bundle Sa.  FIG. 13  shows the cover sheet S 2  in the state in which the front side and back side of the sheet have been reversed after the images have been recorded. 
   The cover sheet S 2  after recording is sent to the cover sheet supporting section  90  of the bookbinding apparatus B, after its front and back sides have been reversed in the image forming apparatus A. After it is aligned in the cover sheet supporting section  90 , the cover sheet S 2  is transported to the trimming position of the cutter  81  by switching back by an amount corresponding to the amount of trimming of its edge part, and has its edge part trimmed (Step  12 ). Thereafter, the operation proceeds to Step  13 , the cover sheet S 2  with its edge part trimmed is joined with the bundle of sheets Sa, and the bookbinding operation is conducted by wrapping the cover sheet S 2  around the sheet bundle Sa. The bound book S 3  is discharged to the book discharging section  100  of the bookbinding apparatus B (Step  14 ), and the sequence of the operations of preparing the book S 3  is completed. 
   Next, explanation is given below for the case when the thickness information of the sheet bundle Sa is obtained by the multiplication of the number of sheets obtained from the image information for sheets S 1  received via the personal computer PC or the like, or the number of sheets obtained from number of original document sheets counted by the document feeder A 2  of the image forming apparatus A, by the thickness of the thickness information per each sheet of the sheets S 1 . 
   After Step  5  or Step  6  of  FIG. 9 , the operation proceeds to Step  15  of  FIG. 11 . The number of sheets S 1  required is grasped from the image information for sheets S 1  received via the personal computer PC or the like, or from the information of the number of sheets inputted from the operation section of the image forming apparatus A, or from the number of sheets obtained from number of original document sheets counted by the document feeder A 2  of the image forming apparatus A. 
   The operation then proceeds to Step  16 , and the CPU of the image forming apparatus A computes the thickness of the sheet bundle Sa by multiplying the number of required sheets S 1  by the value of the thickness of each sheet S 1 . The value of the thickness of each sheet S 1  have been stored beforehand in the storage device ROM of the image forming apparatus A for each type of sheets such as thick sheet, ordinary sheet, thin sheet, or according to the basis weight of the paper. Thus, by specifying the type of sheet S 1  used by the operator, the value of the thickness of the sheet S 1  can be determined. 
   Next, in Step  17 , according to the thickness of the sheet bundle Sa that has been obtained, the amount of trimming of the edge part of the cover sheet S 2  is determined. Further, according to this amount of trimming, the recording positions of the images is determined in each of the areas of the front cover page, the back cover page, and the spine part of the cover sheet S 2 . At this time, similar to the explanation that was given for Step  10 , in the case of an apparatus in which the size of the sheets S 1  constituting the book S 3  and the size of the cover sheet S 2  can be selected, the amount of trimming and the recording positions are derived considering also the size information of the sheets S 1  and the size information of the cover sheet S 2 . On the other hand, in the case of a system in which the size of the sheets S 1  that can be book-bound is limited to only one size and also cover sheet S 2  of only one pre-determined size can be used, it is not necessary to consider the size information of the sheets S 1  or the size information of the cover sheet S 2  at the time of computing the amount of trimming and the recording position. The same is true even regarding shifting the position of recording images according to the amount of trimming. 
   Next, the operation proceeds to Step  18 , and the respective images are recorded by the image forming section of the image forming apparatus A at the image recording positions in each of the area of the cover sheet S 2  as determined earlier. Here, by carrying out image forming on the cover sheet S 2  before carrying out image forming on each of the sheets S 1 , the operations of the succeeding Step  19  and Step  20  can be carried out in parallel, and hence the productivity of producing the book S 3  can be enhanced. 
   The cover sheet S 2  on which images have been formed is sent to the bookbinding apparatus B after its front and back sides are inverted in the image forming apparatus A, and in Step  19 , the edge part of the cover sheet S 2  is trimmed by the cutter  81  of the bookbinding apparatus B based on the amount of trimming determined in Step  17 . After the cover sheet S 2  with images formed on it is sent to the cover sheet supporting section  90  of the bookbinding apparatus B and has been aligned there, it is switch-back transported by a distance based on the amount of trimming of its edge part and sent to the cutting position, whereupon it is trimmed by the cutter  81 . After trimming the edge part of the cover sheet S 2 , the operation proceeds to Step  22 . 
   On the other hand, simultaneously with Step  19 , in the image forming apparatus A, the image forming is carried out of each of the sheets S 1  (Step  20 ). When the image forming of all the necessary sheets S 1  has been completed (Step  21 ), the operation proceeds to Step  22 . In Step  22 , the cover sheet S 2  whose edge part has been trimmed is joined with the sheet bundle Sa and the processing of bookbinding by wrapping the cover sheet S 2  around the sheet bundle Sa is carried out. The bound book S 3  is discharged to the book discharging section  100  of the bookbinding apparatus B (Step  23 ), and the sequence of operations for preparing book S 3  ends. 
   The above explanations of the flow charts are for the case in which the image recording on the cover sheet S 2  and the image recording on the sheets S 1  are both carried out in the image forming apparatus A. However, in a system in which the bookbinding apparatus B is provided with a second image recording unit  85  and a second cover sheet storage section  80 , while the cover sheet S 2  is sent from the second cover sheet storage section  80  and images are recorded on the cover sheet S 2  in the second image forming unit  85 , image recording on the sheets S 1  can be carried out in the image forming section of the image forming apparatus A. Because of this type of control, since it is possible to carry out separately the image recording on the cover sheet S 2  and the image recording on the sheets S 1 , the productivity of preparing the book S 3  can be enhanced. The flow chart shown in  FIG. 12  is a flow chart related to such a type of control. 
   The operations proceed to Step  24  after Step  5  or Step  6  in  FIG. 9 . The number of sheets S 1  required is grasped from the image information for sheets S 1  received via the personal computer PC or the like, or from the information of the number of sheets inputted from the operation section of the image forming apparatus A, or from the number of sheets obtained from number of original document sheets counted by the document feeder A 2  of the image forming apparatus A. 
   The operations moves on to Step  25 , and the CPU of the image forming apparatus A computes the thickness of the sheet bundle Sa by multiplying the number of required sheets S 1  by the value of the thickness of each sheet S 1 . However, the value of the thickness of each sheet S 1 , similar to the case that has already been described above, have been stored beforehand in the storage device ROM of the image forming apparatus A for each type of sheets such as thick sheet, ordinary sheet, thin sheet, or according to the basis weight of the paper. Thus, by specifying the type of sheet S 1  used by the operator, the value of the thickness of the sheet S 1  can be determined. 
   Subsequently, the operation proceeds to Step  26 , and the amount of trimming of the edge part of the cover sheet S 2  is determined according to the obtained thickness of the sheet bundle Sa. Further, in accordance with that trimming amount, the positions of recording images are determined for each of the areas of the front cover page, the spine part of the cover, and for the back cover page. At this time, similar to the case that has been described above, in the case of an apparatus in which the size of the sheets S 1  constituting the book S 3  and the size of the cover sheet S 2  can be selected, the amount of trimming and the recording positions are derived considering also the size information of the sheets S 1  and the size information of the cover sheet S 2 . On the other hand, in the case of a system in which the size of the sheets S 1  that can be book-bound is limited to only one size and also cover sheet S 2  of only one predetermined size can be used, it is not necessary to consider the size information of the sheets S 1  or the size information of the cover sheet S 2  at the time of computing the amount of trimming and the recording position. The same is true even regarding shifting the position of recording images according to the amount of trimming. 
   Next, the operation moves on to Step  27 , and the recording of images starts on sheets S 1  in the image forming section of the image forming apparatus A. The image recording is continued in the image forming apparatus A until the recording is completed on all the sheets S 1  constituting the book S 3  (Step  28 ). In parallel with the image recording in the image forming apparatus A, in the bookbinding apparatus B, a cover sheet S 2 B is sent out from the second cover sheet storage section  80  of the bookbinding apparatus B, and image recording is conducted on the cover sheet S 2 B by the second image recording unit  85  (Step  29 ). At this time, recording of the respective images on the cover sheet S 2 B is made so that the image recording positions match with those in each of the areas of the front cover page, the spine cover part, and the back cover page of the cover sheet S 2  determined in Step  26 . 
   Subsequently, the operation moves on to Step  30 , the cover sheet S 2 B with images formed in each of the areas of it is sent to the cover sheet supporting section  90 , and after it has been aligned there, it is switch-back transported by a distance based on the amount of trimming of its edge part and is sent to the cutting position of the cutter  81 . After that, the edge part of the cover sheet S 2 B is trimmed. 
   When all the image recording on the sheets S 1  and the trimming of the edge part of the cover sheet S 2 B has been completed, the operation proceeds to Step  31 , the cover sheet S 2 B is joined with the sheet bundle Sa and the processing of bookbinding by wrapping the cover sheet S 2 B around the sheet bundle Sa is carried out, and the bound book S 3  is discharged to the book discharging section  100  of the bookbinding apparatus B (Step  32 ), and the sequence of operations of preparing the book S 3  ends. 
   &lt;Stapling-bookbinding Apparatus C&gt; 
   Next, as the second preferred embodiment, a stapling-bookbinding apparatus C using staples as the device for bookbinding is described below. 
     FIG. 14  is an outline cross-sectional view diagram of a stapling-bookbinding apparatus. The parts with the same numbers as in  FIG. 1  are abbreviated here. Also, further explanations are omitted because the operations are almost the same as in the case of the pasting and bookbinding operation excepting that stapling is used as the bookbinding method. 
   In  FIG. 14 , a stapling device  140  is used instead of the paste coating device  60 , and  FIG. 15(   a  ) is a diagram showing the process of square spine formation without coating paste on the bottom surface SA of the bundle of sheets Sa. 
     FIG. 15  ( b ) a perspective view diagram showing a booklet that has been joined with a cover sheet and has have a square spine formed being lowered to the position of the stapling section  141 . After this, the stapling section  141  moves in the direction of the arrow, and the staples  142  are stapled at the prescribed positions. Although the staples are exposed in the case of the stapling-bookbinding method and the product quality get deteriorated compared to the pasting and bookbinding method, this type of bookbinding is used widely because the structure is simple.