Abstract:
Bookbinding unit that, in feeding cover sheets to a predetermined cover-fitting position, is able to feed various sheets/leaves, yet without defacing of or scratch marks in the cover sheets, nor press marks during cover formation, occurring. Provided are an incoming sheet conveyance path for sequentially bringing in printed sheets; a stacking tray unit for stacking and collating into bundles sheets from the conveyance path; a bookbinding process path that transports sheet bundles from the stacking tray unit to a predetermined cover-binding position; and a cover feed path for feeding cover sheets to the cover-binding position. A protective-sheet storage tray for supplying jacketing sheets is annexed to the cover feed path, and a conveyance unit that overlays fed cover sheets with jacketing sheets from their storage tray and transports the jacketed cover sheets to the cover-sheet binding position is disposed in the cover feed path.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention-involving bookbinding units that collate into bundles sheets conveyed out from photocopiers, printers, and the like, and finish the bundles into cover-sheet bound booklets-relates to improvements in cover-sheet feeding mechanisms for the encasing of inner-bound sheet bundles in cover sheets. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, this kind of bookbinding unit collates into sheet bundles on a stacking tray sheets conveyed out from an image-forming unit, and applies adhesive to a spine portion of the sheet bundle. Meanwhile, a cover sheet is fed from an inserter (a feeding apparatus) disposed upstream of the image-forming unit or stacking tray to a cover-sheet binding position provided downstream of the adhesive application position. Then the sheet bundle coated with adhesive at the cover-sheet binding position is joined to the central portion of the cover sheet in an upside-down T-configuration, and the cover sheet is folded to form shoulders on the sheet bundle (to form the booklet). These processes are known in the art. 
         [0005]    This type of system is disclosed in Japanese Unexamined Pat. Pub. App. No. 2005-305822 (cf.  FIG. 1 ). In the disclosure, a stacking tray is linked to a sheet discharge outlet of an image-forming unit. The printed sheets are stacked on that tray. After the spine portion of sheets collated into a bundle is coated with adhesive, the sheet bundle is conveyed to a downstream binding position. A cover-sheet supply path that branches from an incoming sheet conveyance path to convey sheets to the stacking tray is provided in the cover-sheet binding position; cover sheets are conveyed from the cover sheet supply path and set into the cover-sheet binding position. 
         [0006]    Although it is not disclosed in the publication mentioned above, a system configuration is already known wherein an inserter unit (a feeding apparatus) is disposed between the image-forming unit and the cover-sheet binding position (stage) to selectively convey cover sheets from the inserter unit and the image-forming unit. 
         [0007]    When a cover sheet is automatically conveyed to the cover-sheet binding position (the bookbinding stage) as described above, conventionally, the cover sheet is fed either from a stacker in the image-forming unit connected to the bookbinding unit or it is fed from a stacker in the inserter unit connected to the bookbinding unit. In such a case, the cover sheet is either fed from the stacker via the image-forming unit, or from a stacker disposed outside of the bookbinding unit to the bookbinding position via inside the bookbinding unit. Therefore, the bookbinding unit is provided sheet guides and a conveyance roller that convey the cover sheet from the stacking position to a predetermined binding position. 
         [0008]    Various types of paper are used as cover sheets in a bookbinding unit. For example, special sheets such as glossy paper, one surface of which is coated with a varnish, cover-sheet paper covered with fabric, or windowed sheets with an opening to expose a title have been used. There is a problem with those kinds of special sheets in that the conveyance mechanisms, such as rollers, belts, and sheet guides, peel away the cover sheet coating layer. Therefore, special sheets cannot be used as cover sheets in a conventional apparatus configuration. 
         [0009]    In other words, when using special paper like the ones described above as cover sheets, friction marks, abrasions, and other kinds of defacement caused by the conveyance rollers occur on surfaces of coated sheets or fabric-covered sheets. There is also the problem of an edge of a windowed sheet becoming jammed on the paper guides and the like. 
         [0010]    Furthermore, after the cover sheet is conveyed to the cover-sheet binding position, the cover sheet is folded over the spine of the inner-bound leaf bundle by pressing members. The cover sheet at this time is folded by pressing members. When the cover sheet is sandwiched between the pressing members, these members can leave pressing marks on the cover sheet surface, thereby creating the problem of a poor esthetic appearance of the finished book. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    Therein, the inventors arrived at the concept of, when conveying special cover sheets from a stacker to a predetermined binding position, preventing friction marks, abrasions and paper jams by overlaying a for-conveyance protective sheet onto the cover sheets and conveying them. 
         [0012]    A main object of the present invention is to provide a bookbinding unit that feeds various types of sheets when feeding a cover sheet from a stacker to predetermined cover binding position, and does not deface, cause friction marks or pressing marks on the cover sheet surface when forming the cover. 
         [0013]    The present invention employs the following configuration to solve the problems discussed above. A bookbinding unit according to the present invention is equipped with stacking tray means for stacking into bundles, and supporting, sheets on which images have been formed; a bookbinding path for guiding the sheet bundle from the stacking tray means to a predetermined cover-sheet binding position; a cover feed path for feeding a cover sheet to the cover-sheet binding position; and protective-sheet storage tray that supplies a jacketing sheet to the cover feed path. Further, a conveyance means that overlays fed cover sheets with jacketing sheets supplied from the protective-sheet storage tray and that transports these the jacketed cover sheets to the cover-sheet binding position is disposed in the cover feed path. 
         [0014]    The protective-sheet storage tray is disposed in a feeder unit that feeds the cover sheet to the cover feed path, and is configured to selectively supply cover sheets to the cover feed path from either the feeder unit or from the image-forming unit. 
         [0015]    The protective-sheet storage tray is disposed in the feeder unit that feeds cover sheets to the incoming sheet conveyance path. This feeder unit also has a first tray member that stores the cover sheets, and a second tray member that stores jacketing sheets. 
         [0016]    The conveyance means disposed in the incoming sheet conveyance path or the cover feed path has a registration means that momentarily pauses a jacketing sheet from the protective-sheet storage tray and overlays it with a cover sheet conveyed from the incoming sheet conveyance path. The registration means is configured to underlay the jacketing sheet along the spine-cover side of the cover sheet. 
         [0017]    Cutting means is disposed downstream of the cover sheet binding means in the bookbinding path. The cutting means is configured to trim true and align the edges of the covered sheet bundle. The cutting means cuts the jacketing sheets at the same time as trimming the edges of the sheet bundle for alignment. Also, stacking means for storing the bound sheets is provided at a downstream side of the cutting means. The stacking means is configured to store sheet bundles and jacketing sheets that have been trimmed true and aligned by the cutting means. 
         [0018]    An image forming system according to the present invention is composed of an image-forming unit that sequentially forms predetermined images on sheets, and a bookbinding unit connected to a discharge outlet of the image-forming unit, that collates sheets having printed images into a stack or sheet bundle and binds that sheet bundle to a cover sheet. The bookbinding unit is configured as described above. 
         [0019]    The present invention provides a protective-sheet storage tray that stores jacketing sheets in the cover feed path of the bookbinding unit. When conveying a cover sheet to the predetermined binding position, the cover sheet is overlaid with a jacketing sheet during conveyance, which has the following effects. 
         [0020]    The cover sheet is covered by a jacketing sheet when being conveyed through the cover feed path so no markings from abrasion or friction caused by conveyance roller and the like remain on the cover sheet. The cover sheet is also not defaced by rollers and the like. Cover sheets with an opening for a title and the like do not get jammed by the roller or paper guides and the like. In such a case, it is possible to solve the problem of degraded appearance of the cover sheet after the bookbinding process by overlaying a jacketing sheet over the cover sheet. 
         [0021]    Also, the present invention provides a feeder unit in the bookbinding unit. A cover sheet storage tray and a jacketing sheet storage tray are attached to this unit. Because it is configured to overlay a jacketing sheet over a cover sheet when the cover sheet is being fed to the cover-sheet binding position, the structure is simple and low-cost, and can solve the problems of defacing or damaging sheets, and paper jams. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0022]      FIG. 1  is an overall view of an image-forming system equipped with a bookbinding unit of the present invention; 
           [0023]      FIG. 2  is a detailed explanatory view of the bookbinding unit in the system shown in  FIG. 1 ; 
           [0024]      FIGS. 3A and 3B  show a configuration of an adhesive applicator means in the unit shown in  FIG. 2 ;  FIG. 3A  is block diagram of an adhesive container;  FIG. 3B  is an explanatory view of an aspect of an adhesive applicator; 
           [0025]      FIG. 4  is an explanatory view of a configuration of a cover sheet binding means, sheet-bundle attitude biasing means, and cutting means in the unit shown in  FIG. 2 ; 
           [0026]      FIG. 5  is an expanded view of the essential portion of  FIG. 2 , showing a cover feed path; 
           [0027]      FIGS. 6A and 6B  are explanatory views of a cover sheet conveyance state in the unit shown in  FIG. 2 ;  FIG. 6A  shows a cover sheet being conveyed from an inserter unit;  FIG. 6B  shows the cover sheet being conveyed from the image-forming unit; and 
           [0028]      FIG. 7  is a block diagram of a configuration of control means in the system shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    A preferred embodiment of the present invention will now be explained with reference to the drawings provided.  FIG. 1  is an explanatory view of a bookbinding unit according to the present invention, and an overall configuration of an image-forming system using the bookbinding unit;  FIG. 2  is a detailed explanatory view of the bookbinding unit.  FIG. 5  is an expanded view of the essential portion of  FIG. 2 , showing a cover feed path.  FIG. 6  is an explanatory view of the conveyance of the cover sheet. 
         [0030]    As shown in  FIG. 1 , the image-forming system of the present invention is composed of an image-forming unit A that sequentially forms images on sheets, and a bookbinding unit B connected to a discharge outlet  14  of the image-forming unit A, that collates into sheet bundles sheets formed with images, binds the sheet bundle to form a booklet and trims the booklet. Also, a first sheet-supplying tray means  26   a  that stores cover sheets, and a second sheet-supplying tray means  26   b  that stores jacketing sheets are provided in the bookbinding unit B. Also, a finishing unit C is disposed downstream of the bookbinding unit B in the apparatus of  FIG. 1 . The following will now describe the configuration of each unit in detail. 
       Cover Sheet Feeding Method 
       [0031]    First, the feeding method of the present invention will be explained with reference to the schematic drawings of  FIGS. 5 and 6A  and  6 B. The bookbinding unit B according to the present invention has a conveyance path  31  that sequentially conveys sheets out of the image-forming unit A. As described below, the bookbinding unit B is configured to feed a sheet from the conveyance path  31  to the stacking tray means (stacking tray  41 ) that collates the inner leaves of the sheet bundle Sn and the cover-sheet binding position F that binds the cover sheet Sh. The system is configured to feed sheets from the conveyance path  31  to a stacking tray means (hereinafter referred to as stacking tray  41 ) that collates the inner leaves of the sheet bundle Sn as described below, and to convey the cover sheet Sh to the cover-sheet binding position F. 
         [0032]    The present invention equips a protective-sheet storage tray (second feeding tray  26   b ) in the conveyance path (that configures a portion of the cover feed path)  31  described above. For that reason, the protective-sheet storage tray  26   b  and a feeding path  27  that conveys a jacketing sheet from that tray to the conveyance path  31  are connected to the conveyance path  31 . 
         [0033]    It is preferable that the protective-sheet storage tray  26   b  is installed in an inserter unit (paper feeding device)  26  that feeds cover sheets Sh to the conveyance path  31 . In such a case, the inserter unit  26  can be configured to be built-in to the bookbinding unit B or to be a separate unit in a housing separate from the bookbinding unit. The device shown in the drawings is integrated to the inside of the bookbinding unit B, and the first sheet-supplying tray means  26   a  and second sheet-supplying tray means  26   b  that store cover sheets Sh are disposed with one above the other. In this way, the present invention selectively feeds a cover sheet Sh from the image-forming unit A or the inserter unit  26  to the cover-sheet binding position F (bookbinding stage) described below. 
         [0034]    The present invention also overlayingly feeds the cover sheet Sh fed from the image-forming unit A or the inserter unit  26  and a jacketing sheet Sc from the protective-sheet storage tray  26   b  to the cover-sheet binding position F, and creates a booklet by overlaying both sheets simultaneously at that position. Overlaying the jacketing sheet Sc and cover sheet Sh will be explained for (1) feeding the cover sheet Sh from the inserter unit  26 , and (2) feeding the cover sheet Sh from the image-forming unit A. 
         [0000]    Feeding Cover Sheets Sh from Inserter Unit  26   
         [0035]    As shown in  FIG. 5 , the inserter unit  26  is disposed in a position where it is linked to the conveyance path  31 . The first sheet-supplying tray means  26   a  and the second sheet-supplying tray means  26   b  are arranged with one above the other in the inserter unit  26 . A kick-roller  26   k  and separating means (a roller or belt or the like)  26   s  are disposed in each tray. Also, the feeding path  27  that is connected to the conveyance path  31  is equipped downstream of the separating means  26   s . Aligning means  27   a  that overlays sheets from the first sheet-supplying tray means  26   a  and second sheet-supplying tray means  26   b  is equipped in the feeding path  27 . This aligning means  27   a  is composed of a mechanism such as a gate stopper or pair of registration roller and the like, for example, to engage the leading edges of the cover sheet Sh and jacketing sheet Sc fed simultaneously to the feeding path  27  to overlay the sheets. Note that the present invention is configured to either have a plurality of sheets set in the second sheet-supplying tray means  26   b  that stores jacketing sheets and sends them separately as shown in the drawing, or to manually feed one cover sheet at a time in the tray (not shown). 
         [0036]      FIG. 6A  shows aligning means  27   a  composed of a gate stopper. This gate stopper  27   a  is composed, as described below, to be moved from the feeding path  27  to a retreated position (dashed lines in the drawing) by a solenoid, not shown. Two sheets the leading edges thereof stopped by the aligning means  27   a  are overlaid and fed to the conveyance path  31  by downstream conveyance roller  27   b . The cover sheet Sh and jacketing sheet Sc fed to the conveyance path  31  using this configuration are fed to a predetermined cover-sheet binding position F from the cover feed path  34 , described below. 
         [0000]    Feeding Cover Sheets Sh from Image-Forming Unit A 
         [0037]    As shown in  FIG. 5 , only the jacketing sheet Sc from the second sheet-supplying tray means  26   b  of the inserter unit  26  is fed to the feeding path  27 , and from this path the jacketing sheet Sc is conveyed to the conveyance path  31 . A buffer path  34   t  is provided in the conveyance path  31  to temporarily idle the jacketing sheet Sc. The drawing shows that the buffer path  34   t  is disposed downstream of the conveyance roller  31   b  disposed in the conveyance path  31 . This buffer path  34   t  is disposed in the cover feed path  34  described below. An aligning mechanism  35  that aligns the cover sheet Sh and forward and reverse rotating roller  35   r  for aligning the sheets are disposed in this path.  35   a  in the drawing denotes a nipping claw for aligning;  35   b  denotes an aligning member that aligns sheets in a direction perpendicular to the conveyance direction. The jacketing sheet Sc fed from the conveyance path  31  to the forward and reverse rotating roller  35   r  is switched back by the forward and reverse rotating roller  35   r . When this happens, the jacketing sheet Sc is idled at the buffer path  34   t  directly below the conveyance roller  31   b.    
         [0038]    In this state, as shown in  FIG. 6B , the cover sheet Sh is fed from the image-forming unit A to the conveyance path  31 . At this time, the conveyance roller  34   a  and the forward and reverse rotating roller  35   r  of the cover feed path  34  are configured to be retreated upward from the cover feed path. Therefore, the cover sheet Sh fed to the conveyance path  31  is conveyed over the jacketing sheet Sc temporarily idled in the buffer path  34   t  and both sheets are overlaid one over the other. Then, both sheets are aligned by the aligning mechanism  35  described below and fed to the downstream cover-sheet binding position F. 
       Configuration of Image-Forming Unit 
       [0039]    As shown in  FIG. 1 , the image-forming unit A can adopt a variety of structures of a copier, printer or printing machine. The drawing shows an electrostatic printing system. This image-forming unit A has a feeding unit  2 , printing unit  3 , discharge unit  3  and control unit in the casing  1 . A plurality of cassettes  5  corresponding to sheet sizes is prepared at the feeding unit. Sheets of the size specified by the control unit are fed to the sheet feed path  6 . A registration roller  7  is equipped at the sheet feed path  6 . After the leading edge of the sheet is registered by this roller, it is fed at a predetermined timing to the downstream printing unit. 
         [0040]    A static electric drum  10  is equipped at the printing unit  3 . A print head  9 , a developer  11  and a transfer charger  12  are disposed around this drum  10 . The print head  9  is composed of a laser emitter, for example, to form electrostatic latent images on the electrostatic drum  10 . Toner ink adheres to the latent image at the developer  11 , and this is transferred and printed on the sheet at the transfer charger  12 . The printed sheet is the fixed at the fixer  13  and discharged to the discharge path  17 . A discharge outlet  14  formed in the casing  1  and a discharge roller  15  is disposed at the discharge unit  4 . The symbol  16  in the drawing denotes a recirculation path. A printed sheet from the discharge path  17  is turned over from front to back at the switchback path and fed to the registration roller  7  to be formed with images on its backside. In this way, a sheet formed with images on one side or both sides is conveyed from the discharge outlet  14  by the discharge roller  15 . 
         [0041]    The symbol  20  in the drawing denotes a scanner unit. This optically reads original images to print using the print head  9 . As is generally known in the art, the scanner is composed of a platen  23  where an original sheet is set; a carriage  21  that scans the original image along the platen  23 ; and an optical reading means (for example, a CCD device) that photo-electrically converts optical images received from the carriage  21 . The drawing shows an original feeding apparatus  25  that automatically feeds the original sheet to the platen, installed over the platen  23 . 
       Configuration of Bookbinding Unit 
       [0042]    Next, the bookbinding unit B connected to the image-forming unit A will now be explained with reference to  FIG. 2 . The bookbinding unit B is composed of a stacker  40  that stacks and aligns printed sheets into bundles; an adhesive applicator means  55  that applies adhesive to the sheet bundle conveyed from the stacker  40 ; and cover sheet binding means  60  that binds the cover sheet to the sheet bundle applied with adhesive, in the casing  30 . 
       Configurations of Conveyance Paths 
       [0043]    A conveyance path  31  having a conveyance inlet  31   a  linked to the discharge outlet  14  of the image-forming unit A is provided in the casing  30 , and the inner sheet conveyance path  32  and cover feed path  34  are linked from this conveyance path  31  via the path switching flapper  36 . The bookbinding process path  33  is linked to the cover feed path  34  via the stacker  40 , and a finishing path  38  is connected to the cover feed path  34 . The bookbinding process path  33  is disposed to traverse the apparatus longitudinally in a substantially vertical direction, and the cover feed path  34  is disposed in a direction to traverse the apparatus in a horizontal direction. 
         [0044]    The bookbinding process path  33  and the cover feed path  34  mutually intersect (orthogonally); the cover sheet binding means  60 , described below, is disposed in the intersection. The conveyance path  31  configured as described above is linked to the discharge outlet  14  of the image-forming unit A to receive printed sheets from the image-forming unit A. Sheets Sn printed with content information (the inner leaves of sheets), and a sheet Sh printed with a title and the like to be used as a cover sheet (a cover sheet) are conveyed out from the image-forming unit A. This conveyance path  31  is branched into the inner sheet conveyance path  32  and the cover feed path  34 , and sorts printed sheets to convey them into each path by the use of a path switching flapper  36 . 
         [0045]    On the other hand, the inserter unit  26  is connected to the conveyance path  31 . This is configured to feed a cover sheet Sh not printed at the image-forming unit A one at a time from the first sheet-supplying tray means  26   a  to the conveyance path  31 . The first sheet-supplying tray means  26   a  and second sheet-supplying tray means  26   b  are arranged with one above the other in this inserter unit  26  as described above. The first sheet-supplying tray means  26   a  stores the cover sheets Sh; the second sheet-supplying tray means  26   b  stores the jacketing sheets Sc. The kick-roller  26   k  and separating means  26   s  are provided in each tray; sheets are kicked out of the tray by the kick-roller  26   k , and separated into single sheets by the separating roller  26   s  and conveyed downstream. Also, the feeding path  27  that is connected to the conveyance path  31  is equipped downstream of the separating means  26   s . Aligning means  27   a  that overlays sheets from the first sheet-supplying tray means  26   a  and second sheet-supplying tray means  26   b  simultaneously or in tandem is equipped in the feeding path  27 . 
         [0046]    The conveyance roller  31   b  is disposed in the conveyance path  31 ; the conveyance roller  32   b  is disposed in the inner sheet conveyance path  32 ; the gripping conveyance means  47 , the sheet-bundle attitude biasing means  64  described below, and discharge roller (discharge means)  66  are disposed in the bookbinding process path  33 . The conveyance roller  34   a  is disposed in the cover feed path  34 , the conveyance roller  38   a  is disposed in the finishing path  38 , and each of these rollers is connected to a drive motor. 
         [0047]    A configuration of the cover feed path  34  will now be explained with reference to  FIGS. 4 and 5 . This path is arranged to intersect the bookbinding process path  33  branching from the conveyance path  31 ; the cover-sheet binding position (bookbinding stage) F is disposed in this intersection. The conveyance roller  34   a  that convey the cover sheet Sh and the aligning mechanism  35  are disposed in the bookbinding process path  33 . Also, the path guide that forms the cover feed path  34  is composed of a guide  34   g  that is movable in up and down directions between a guide posture and retreat posture upstream and downstream of the cover-sheet binding position F. This is so that it is positioned in the guide posture (see  FIG. 2 ) when guiding the cover sheet Sh to the cover-sheet binding position F, and can shift to the retreated posture (see  FIG. 4 ) when the cover sheet Sh is being folded. 
         [0048]    The aligning mechanism  35  is composed of a nipping claw  35   a  disposed in the cover feed path  34  to engage a trailing end of the cover sheet Sh, an aligning member  35   b  that offsets the cover sheet Sh gripped by the nipping claw in a direction perpendicular to the direction of conveyance, and the forward and reverse rotating roller  35   r  that switches back the cover sheet Sh fed to the cover feed path  34  to touch the nipping claw  35   a . The forward and reverse rotating roller  35   r  is configured to rise and lower to and from an idling position retreated above the cover sheet Sh. 
         [0049]    The cover sheet Sh conveyed into the cover feed path  34  is switched back and conveyed by the reverse rotation of the forward and reverse rotating roller  35   r  after its trailing end passes the aligning means  27   a . When doing so, the trailing end of the sheet is aligned to remove any skewing (traveling at an angle) of the sheet by abutting the nipping claw  35   a . In this state, the nipping claw  35   a  grips the trailing end of the sheet and the aligning means  35   b  mounted with the nipping claw  35   a  moves in a direction perpendicular to the direction of conveyance to align the sides of the sheet. This corrects any skewing in the cover sheet Sh in the front and back directions, and corrects the position of the width direction of the sheet (side position correct). The cover sheet Sh having been aligned in this way is conveyed toward the downstream cover-sheet binding position F by the forward and reverse rotating roller  35   r  and set at that position. The cover sheet Sh is conveyed and set at the cover-sheet binding position F by being conveyed from the aligning position a predetermined conveying amount. Note that the present invention aligns and corrects skewing while the jacketing sheet Sc is overlaying the aligned cover sheet Sh. 
       Configuration of Stacker 
       [0050]    The stacking tray  44  arranged at the discharge outlet  32   b  of the inner sheet conveyance path  32  stacks and stores sheets from the discharge outlet  32   b  in a bundle. As shown in  FIG. 2 , the stacking tray  41  is composed of a tray member disposed substantially laterally, and is equipped thereabove with forward and reverse rotating roller  42   a  and conveyance guide  42   b . Also, printed sheets from the conveyance outlet  32   b  are guided onto the stacking tray  41  by the conveyance guide  42   b  and stored by the forward and reverse rotating roller  42   a . The forward and reverse rotating roller  42   a  moves the printed sheet to the leading edge of the stacking tray  41  with a forward rotation, and controls the trailing end of the sheet to abut an aligning member  43  provided at a trailing edge of the tray (see  FIG. 2 ) with a reverse rotation. Sheet side aligning means, not shown, are provided in the stacking tray  41  to align the sides of the printed sheet in the tray using the both sides as a reference. The printed sheets from the inner sheet conveyance path  32  are sequentially lifted into the stacking tray  41  and collated to form a sheet bundle. 
         [0051]    A sheet bundle thickness identifying means, not shown, is installed on the stacking tray  41  to detect the thickness of the sheet bundle stacked in the tray. With this configuration, a paper touching piece is installed to touch the top sheet on the tray. A sensor detects the position of the paper touching piece to identify the thickness of the sheet bundle. As another sheet bundle thickness identifying means, a discharge sensor Se 3  detects sheets conveyed out to the stacking tray. A counter is provided to count the signals emitted from the sensor. It is possible to determine the thickness of the sheet bundle by multiplying the total number of sheets counted at the job end signal sent from the image-forming unit A by the average thickness of a single sheet. 
       Configuration of Sheet-Bundle Conveyance Means 
       [0052]    Gripping conveyance means  47  is disposed in the bookbinding process path  33  to move the sheets from the stacking tray  41  to the downstream adhesive application position E. This gripping conveyance means  47  changes the orientation of the sheet bundle stacked on the stacking tray  41  as shown in  FIG. 2  from a horizontal posture to a vertical posture, and conveys the sheet bundle to the adhesive application position E along the bookbinding process path  33  disposed in a substantially vertical direction. For that reason, the stacking tray  41  moves to a handing-over position (dashed lines in  FIG. 2 ) from the stacking position (solid lines in  FIG. 2 ) to hand-over the sheet bundle to the gripping conveyance means  47  ready at the handing-over position. 
       Configuration of Adhesive Application Unit 
       [0053]    Adhesive application means  55  is provided in the adhesive application position E of the bookbinding process path  33 . As shown in  FIG. 3(   a ), the adhesive application means  55  is composed of an adhesive container  56  that stores hot-melt adhesive, an applicator roller  57  and a roller rotating motor MR. The adhesive container  56  is separated into a liquefied adhesive compartment (hereinafter referred to as the liquid adhesive compartment)  56   a  and a solid adhesive compartment  56   b , and the applicator roller  57  is rotatably installed in the liquid adhesive compartment  56   a . An adhesive sensor  56 S (see  FIG. 2)  is installed in the liquid adhesive compartment  56   a  to detect the amount of adhesive remaining therein. The adhesive sensor  56 S shown in the drawing also functions as an adhesive temperature sensor. In other words, it detects the temperature of the liquefied adhesive in the liquid adhesive compartment  56   a  and at the same time, it detects the amount of adhesive remaining according to the temperature difference of the portion immersed in the adhesive. Heating means  50  such as an electric heater and the like is embedded in the adhesive container  56 . The adhesive sensor  56 S and heating means  50  are connected to a control CPU  75  to adjust the temperature of the adhesive in the liquid adhesive compartment  56   a  to a predetermined melting temperature. The adhesive roller  57  is composed of a porous material that is heat-durable. It is configured to allow a layer of adhesive form around the circumference of the roller by being permeated with adhesive. 
         [0054]    The adhesive container  56  configured this way is reciprocatingly driven along the spine of the sheet bundle. As shown in the conceptual drawing of  FIG. 3(   b ), the adhesive container  56  is formed to be shorter (dimensions) than the bottom edges S 1  of the sheet bundle S (the spine cover sheet portion when forming the booklet), and is supported on a guide rail  52  of the apparatus frame to move along with the adhesive roller  57  along the bottom edges S 1  of the sheets. Also, the adhesive container  56  is connected to a timing belt  53  mounted to the apparatus frame, and a driver motor MS is connected to the timing belt  53 . 
         [0055]    The adhesive container  56  is reciprocated by the drive motor MS between a home position HP and a return position RP where it starts the operation to move along the sheet bundle. Each position is set to relationships shown in  FIG. 3(   b ), and the return position RP is set according to the size information of the sheet width. When the power is turned on, this is set at the home position HP, and after a predetermined amount of time after a sheet grip signal is issued from a grip sensor Sg disposed on the gripping conveyance means  47  for example, this moves from the home position HP to the return position RP. At the same time as the movement, the roller rotating motor MR starts rotating the applicator roller  57 . Note that SP denotes the home position sensor of the adhesive container  56 . With the adhesive application means  55  configured as described above, the rotation of the drive motor MS starts moving the adhesive container  56  along the guide rail  52  from the left side to the right side of  FIG. 3B . In the outward path, the applicator roller  57  presses against the sheet bundle to separate the sheet edges. Then, in the return path where it returns from the return position RP to its home position HP, an elevator motor, not shown, adjusts a feed amount of the gripping conveyance means  47  to form a predetermined gap with the sheet edges and to apply adhesive. 
       Configuration of Cover-Sheet Binding Means 
       [0056]    Cover sheet binding means  60  is disposed in the cover-sheet binding position F of the bookbinding process path  33 . The cover sheet binding means  60  is composed of a spine pressing plate  61 , a spine folding plate  62 , and folding roller  63  as shown in  FIG. 4 . The cover feed path  34  is disposed in the cover-sheet binding position F, and feeds the cover sheet Sh from either the image-forming unit A or the inserter unit  26 . The spine pressing plate  61  is composed of a plate-shaped member to backup and support the cover sheet Sh, and is advancably disposed in the bookbinding process path  33 . The inner leaves of the sheet bundle Sn are joined in an upside-down T shape to the cover sheet Sh supported by this spine pressing plate  61  using adhesive. The spine folding plate  62  is composed of a pair of left and right pressing members. In order to fold the spine of the cover sheet joined in an upside-down T-shape, these members are configured to be mutually brought close together and moved apart by a drive means, not shown. The folding rollers  63  are composed of a pair of rollers that nip the sheet bundle formed with a folded spine to finish the booklet. 
         [0057]    Note that the present invention folds the spine of the cover sheet while the jacketing sheet Sc is overlaying the cover sheet Sh. The jacketing sheet Sc at this time is arranged at a side touching the spine pressing plate  61 , the spine folding plate  62  and the folding roller  63 . Therefore, in the folding process, the cover sheet Sh is not soiled or damaged by touching these pressing members. 
       Configuration of Sheet-Bundle Attitude Biasing Means 
       [0058]    A sheet-bundle attitude biasing means  64  that changes the orientation of the sheet bundle and trimming means  65  that trims edges of the sheet bundle are disposed in the cutting position G downstream of the folding roller  63 . The sheet-bundle attitude biasing means  64  turns the sheet bundle covered with sheet from the cover-sheet binding position F to a predetermined direction (orientation) and conveys it to the downstream trimming means  65  or to a storage stacker  67 . Also, the trimming means  65  cuts the edges of the sheet bundle to align them. For that reason, the sheet-bundle attitude biasing means  64  is provided rotating tables  64   a ,  64   b  that nip the sheet bundle fed from the folding rollers  63  and rotate it. As shown in  FIG. 4 , the rotating tables  64   a  and  64   b  are provided on a unit frame  64   x  risibly mounted to the apparatus frame. The pair of rotating tables  64   a ,  64   b  nip the bookbinding process path  33  and are rotatably supported on the unit frame. On movable rotating table  64   b  is supported to move in a sheet bundle thickness direction (in a direction perpendicular to the bookbinding process path  33 ). Revolving motors Mt 1 , Mt 2  are installed on each rotating table  64   a ,  64   b  to change the orientation of the sheet bundle in the bookbinding process path  33 . A gripping motor Mg that moves in the left and right directions of  FIG. 4  is installed in the rotating table  64   b  of the movable side. 
       Configuration of Trimming Means 
       [0059]    Trimming means  65  is disposed downstream of the sheet-bundle attitude biasing means  64 . As shown in  FIG. 4 , the trimming means  65  is composed of a trimming edge pressing member  65   b  that pressingly supports a trimming edge of the sheet bundle against the blade bearing member  65   a  and a trimming blade unit  65   c . The trimming edge pressing unit member  65   b  is disposed in a position opposing the blade bearing member  65   a  disposed in the bookbinding process path  33 , and is composed of a pressing member that moves in a direction perpendicular by drive means, not shown, to the sheet bundle. The trimming blade unit  65   c  is composed of a flat, blade-shaped cutting blade  65   x  and a cutter motor Mc that drives the blade. With the trimming means  65  of this configuration, predetermined amounts of the edges of the sheet bundle, excluding the spine portion, are cut to finish the booklet. 
         [0060]    Discharge roller (discharge means)  66  and a storage stacker  67  are provided downstream of the cutting position G. As shown in  FIG. 2 , the storage stacker  67  stores the sheet bundle in an upright posture. As shown in  FIG. 1 , the storage stacker  67  is drawably disposed in the casing  30  and can be drawn to the front side of the apparatus (the front side of the sheet of  FIG. 1 ). The user can view from the top direction when it is drawn out to the front side of the apparatus.  67 Sf denotes a full detection sensor. This detects when the sheet bundles stored in the storage stacker have reached a full state and issues a warning to remove them to the operator. 
         [0061]    Note that the present invention trims the sheet bundle when cutting the sheet bundle as described above with the jacketing sheet Sc covering the cover sheet Sh. Therefore, the cover sheet Sh is neither soiled or damaged by directly touching the rotating tables  64   a ,  64   b , and cutting edge pressing means in the cutting process. 
       Configuration of Finishing Unit 
       [0062]    A finishing unit C is disposed in the bookbinding unit B; a finishing path  38  connected to the cover feed path  34  is provided in the finishing unit C; a finishing device such as a stapler, punching unit or stamping unit is disposed in the finishing path  38 . A printed sheet conveyed out of the image-forming unit A is received via the cover feed path  34 , is stapled, punched with a hole or marked, then discharged to the discharge tray  37 . Also, sheets conveyed from the image-forming unit without undergoing any finishing process are stored in the discharge tray  37 . 
       Configuration of Control Means 
       [0063]    The configuration of the control means in the apparatus described above will be now explained with reference to  FIG. 7 .  FIG. 7  shows a control block diagram. In a system linking the image-forming unit A and bookbinding unit B as shown in  FIG. 1 , a control panel  71  and mode setting means  72  are provided in the control CPU  70  installed in the image-forming unit A. Also, the control CPU  75  is provided in the control unit of the bookbinding unit B. The control CPU  75  reads a bookbinding process execution program from ROM  76  and executes each process in the bookbinding process path  33 . 
         [0064]    The control CPU  75  receives from the control CPU  70  in the image-forming unit A a finishing mode instruction signal, job end signal, sheet size information, and other information and command signals required in bookbinding. On the other hand, sheet sensors Se 1  to Se 6  are disposed in the positions shown in the drawing in the conveyance path  31 , bookbinding process path  33  and the cover feed path  34  to detect conveying sheets (sheet bundle). The control CPU  75  is transmitted the detection signals from the sheet sensors Se 1  to Se 6 . The control CPU  75  is provided a stacker control unit  75   a , an adhesive application means control unit  75   b , a cover sheet binding control unit  75   c , a trimming means control unit  75   d , a stacker control unit  75   e , and an adhesive temperature control unit  79 . 
         [0065]    It is to be noted that the present application claims priority rights from Japanese Pat. App. No. 2007-182603, which is herein incorporated by reference.