Patent Publication Number: US-9902586-B2

Title: Sheet processing apparatus capable of creating fold section, method of controlling the same, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a sheet processing apparatus, a method of controlling the same, and a storage medium. 
     Description of the Related Art 
     In conventional sheet processing apparatuses, during production of saddle-stitched books, a folding position for center-fold processing is sometimes displaced from the center of a sheet. The displacement of the folding position from the middle of a sheet is caused e.g. by an assembly error of a sheet processing apparatus, variation in sheets between production lots of the sheets, and a change in sheets due to changes in environmental conditions, such as humidity and temperature. 
     To cope with this, conventionally, several copies are printed for test printing before final production of saddle-stitched books so as to check whether or not a folding position is at an expected position. Then, if the folding position is displaced from the expected position, fine adjustment is performed physically or by software such that the folding position is arranged at the expected position. 
     In relation to this, there has been proposed a sheet processing apparatus that is capable of correcting displacement of a folding position within approximately ±1 mm, by providing two setting items for adjusting the folding position and the stitched position such that they are accurately arranged in the middle of each sheet during production of saddle-stitched books (see e.g. Japanese Patent Laid-Open Publication No. 2001-206626). 
     The two setting items are an item which can be set only by a service technician for correcting the above-mentioned displacement due to an assembly error, and an item which can be set by a user for correcting displacement due to a sheet. 
     This makes it possible to prevent the position on which saddle-stitch processing and center-fold processing are performed from being displaced from the middle of a sheet. 
     For production of saddle-stitched books, in some cases, processing operations up to center-fold processing are performed by a sheet processing apparatus, and subsequent processing operations including saddle-stitch processing are performed using another sheet processing apparatus (off-line apparatus) which is different from the above-mentioned sheet processing apparatus. Further, the off-line apparatuses include one configured to feed sheets one by one by pinching an extending portion (portion of a sheet, which does not overlap when being folded) of an end of a sheet with rollers. In the off-line apparatus of this type, if a sheet is folded in the middle, an extending portion of an end of the sheet is not generated, and as a result, the off-line apparatus cannot accurately feed the sheet (fold section, i.e. signature). 
     A production method in which saddle-stitch processing and processing steps thereafter are performed using an off-line apparatus is generally determined from the viewpoint of productivity, based on related factors, such as a difference in the number of sheets which can be bound, a level of the accuracy of binding, and a level of speed at which the off-line apparatus can perform processing. 
     When producing saddle-stitched books using the above-mentioned production method, a print product generated by the sheet processing apparatus is required to have a center-folding position shifted from the center of a sheet by a predetermined length. 
     The sheet processing apparatus disclosed in Japanese Patent Laid-Open Publication No. 2001-206626 is capable of performing fine adjustment for correcting the displacement of a folding position from the center of a sheet, caused by the above-mentioned assembly error, and displacement of a folding position from the center of a sheet, caused by the above-mentioned variation in sheets. 
     On the other hand, the sheet processing apparatus disclosed in Japanese Patent Laid-Open Publication No. 2001-206626 does not take into consideration shifting of a folding position from the center of a sheet, and further, is not capable of performing adjustment large enough to create a fold section, a fore edge of which is generally required to have a length of 5 mm to 10 mm, demanded by the above-mentioned production method. 
     Further, when shifting a folding position from the center of a sheet, it is necessary to adjust the position of an image to be printed on the sheet in accordance with the adjustment of the folding position. In the sheet processing apparatus disclosed in Japanese Patent Laid-Open Publication No. 2001-206626, however, the image position adjustment is not taken into consideration. 
     SUMMARY OF THE INVENTION 
     The present invention provides a sheet processing apparatus that is capable of creating fold sections which are suitable for an apparatus that performs saddle-stitch processing on fold sections, a method of controlling the sheet processing apparatus, and a storage medium. 
     In a first aspect of the present invention, there is provided a sheet processing apparatus capable of performing folding processing on sheets, comprising a receiving unit configured to receive a distance between a first sheet end and a second sheet end of each sheet assumed to have been folded in two, and a control unit configured to control folding of the sheet such that the distance between the first sheet end and the second sheet end becomes the distance received by the receiving unit. 
     In a second aspect of the present invention, there is provided a method of controlling a sheet processing apparatus capable of performing folding processing on sheets, comprising receiving a distance between a first sheet end and a second sheet end of each sheet assumed to have been folded in two, and controlling folding of the sheet such that the distance between the first sheet end and the second sheet end becomes the received distance. 
     In a third aspect of the present invention, there is provided a non-transitory computer-readable storage device storing a computer-executable program for causing a computer to execute a method of controlling a sheet processing apparatus capable of performing folding processing on sheets, wherein the method comprises receiving a distance between a first sheet end and a second sheet end of each sheet assumed to have been folded in two, and controlling folding of the sheet such that the distance between the first sheet end and the second sheet end becomes the received distance. 
     According to the present invention, it is possible to provide a sheet processing apparatus that is capable of creating fold sections suitable for an apparatus that performs saddle-stitch processing on fold sections, a method of controlling the same, and a storage medium. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing the mechanical configuration of a sheet processing apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a diagram useful in explaining the construction and operation of a finisher appearing in  FIG. 1 . 
         FIG. 3  is a diagram useful in explaining the construction and operation of the finisher appearing in  FIG. 1 . 
         FIG. 4  is a diagram useful in explaining the construction and operation of the finisher appearing in  FIG. 1 . 
         FIG. 5  is a diagram useful in explaining the construction and operation of the finisher appearing in  FIG. 1 . 
         FIG. 6  is a diagram useful in explaining the construction and operation of the finisher appearing in  FIG. 1 . 
         FIG. 7  is a diagram useful in explaining the construction and operation of the finisher appearing in  FIG. 1 . 
         FIG. 8  is a diagram showing the electrical configuration of the sheet processing apparatus according to the first embodiment. 
         FIG. 9  is a diagram showing software module configuration of the sheet processing apparatus according to the first embodiment. 
         FIGS. 10A to 10F  are schematic diagrams of screens which are displayed on a console section appearing in  FIG. 8 . 
         FIG. 11  is a flowchart of a waiting-time process executed by a CPU appearing in  FIG. 8 . 
         FIG. 12  is a flowchart of a scanning process executed by the CPU appearing in  FIG. 8 . 
         FIG. 13  is a flowchart of an output sheet-setting process executed by the CPU appearing in  FIG. 8 . 
         FIG. 14  is a flowchart of a bookbinding determination process executed by the CPU appearing in  FIG. 8 . 
         FIG. 15  is a flowchart of a printing process executed by the CPU appearing in  FIG. 8 . 
         FIG. 16  is a flowchart of a finishing process executed by the CPU appearing in  FIG. 8 . 
         FIG. 17  is a flowchart of a fold setting process executed by the CPU appearing in  FIG. 8 . 
         FIG. 18  is a view of an example of an output obtained when a bookbinding lap is set and processing operations up to center-fold processing have been performed by the sheet processing apparatus according to the first embodiment. 
         FIGS. 19A and 19B  are schematic diagrams showing post-processing steps executed by a post-processing apparatus. 
         FIG. 20  is a cross-sectional view of a fold section-supplying unit appearing in  FIG. 19B . 
         FIGS. 21A and 21B  are diagrams useful in explaining automatic print adjustment performed in accordance with bookbinding lap adjustment, by a sheet processing apparatus according to a second embodiment of the present invention. 
         FIG. 22  is a flowchart of a print instruction process executed in the second embodiment by the CPU appearing in  FIG. 8 . 
         FIG. 23A  is a diagram useful in explaining a change of an imposition reference position calculated by the CPU in a step in the print instruction process shown in  FIG. 22 . 
         FIG. 23B  is a diagram useful in explaining a creep correction amount calculated by the CPU in a step in the print instruction process shown in  FIG. 22 . 
         FIG. 23C  is a diagram useful in explaining a print position adjustment amount calculated by the CPU in a step in the print instruction process shown in  FIG. 22 . 
         FIG. 24  is a diagram showing a saddle-stitch processing apparatus registration screen used in a third embodiment of the present invention, for registering a device that performs saddle-stitch processing. 
         FIG. 25  is a flowchart of a fold setting process executed in the third embodiment by the CPU appearing in  FIG. 8 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The present invention will now be described in detail below with reference to the accompanying drawings showing embodiments thereof. 
       FIG. 1  is a diagram showing the mechanical configuration of a sheet processing apparatus  90  according to a first embodiment of the present invention. 
     In the present embodiment, a multifunction peripheral having functions of a copy machine, a printer, a facsimile machine, and so forth will be described as an example of the sheet processing apparatus  90 . However, the sheet processing apparatus  90  may be a single-function apparatus. 
     In  FIG. 1 , the sheet processing apparatus  90  includes a scanner  119 , a document feeder (DF)  2 , a printer engine  120  including drums for four colors, a sheet feeding deck  14 , and a finisher  109 . 
     First, a scan operation performed mainly by the scanner  119  will be described. 
     When the scan operation is performed by setting an original on an original platen glass, not shown, a user sets the original on the original platen glass, and closes the document feeder  2 . When an opening/closing sensor, not shown, detects that the document feeder  2  has been closed, a reflective original size detection sensor, not shown, disposed within a casing of the scanner  119  detects the size of the set original. 
     Upon detection of the original size, a light source  10  irradiates the original with light, and reflected light enters a CCD  43  through a reflective plate  11  and a lens  12 . The CCD  43  converts the light having entered therein to a digital signal, and sends the converted signal to a controller unit  100  (see  FIG. 8 ) of the scanner  119 . 
     The controller unit  100  performs desired image processing on the received digital signal, converts the processed signal to a laser recording signal, and stores the laser recording signal in a memory (RAM  102 : see  FIG. 8 ) provided therein as image data. 
     When an original is read by setting the original on the document feeder  2 , the user places the original on a tray of an original setting section  3  of the document feeder  2  in a face-up manner. When the original is placed, an original detection sensor  4  detects that the original has been set. 
     When the original detection sensor  4  detects that the original has been set, the controller unit  100  causes an original feeding roller  5  and a conveyance belt  6  to rotate to thereby convey the original to a predetermined position on the original platen glass. 
     After the original is conveyed to the predetermined position, the controller unit  100  performs the same scan operation as that performed on the original platen glass, and stores the scanned image data in the memory. Then, the controller unit  100  discharges the original having been read onto an original discharge tray  9 . 
     If a plurality of originals are set on the document feeder  2 , the controller unit  100  causes an original having been read to be discharged, and at the same time causes a next original to be fed to the original platen glass via the original feeding roller  5  to thereby perform the operation for scanning the next original. Thus, the operation for reading the plurality of originals is performed. 
     Next, a description will be given of a print operation performed by the printer engine  120  as an image forming unit that forms an image on a recording sheet. 
     A recording signal (print image data) temporarily stored in the memory within the controller unit  100  is transferred to the printer engine  120 , and is converted to recording laser beams for respective colors of yellow, magenta, cyan, and black by a laser recording section. 
     Then, the converted recording laser beams are irradiated onto photosensitive members  16  for the respective colors to thereby form electrostatic latent images on the respective photosensitive members. Then, the electrostatic latent images are developed with toner supplied from toner cartridges  17 , respectively, and the thus visualized images are primarily transferred onto an intermediate transfer belt  21  as a primary transfer image. 
     Then, the intermediate transfer belt  21  is rotated clockwise, and when a recording sheet fed from one of sheet feed cassettes  18  or the sheet feeding deck  14  along a sheet feeding conveying path  19  has reached a secondary transfer position  20 , the primary transfer image is transferred from the intermediate transfer belt  21  onto the recording sheet. 
     The recording sheet having the image transferred thereon is pressed and heated by a fixing device  22  to have the toner fixed thereon, and is conveyed along a discharge conveying path. Then, the recording sheet is discharged onto a center tray  23  in a face-down manner or is switched back to a discharge outlet  24  which guides the recording sheet to the finisher  109 , or is discharged onto a side tray  25  in a face-up manner. 
     Flappers  26  and  27  are used for switching the conveying path in order to switch these discharge outlets. In double-sided printing, the flapper  27  switches the conveying path after the recording sheet passes the fixing device  22 , and then the recording sheet is switched back and conveyed downward through a double-sided printing conveying path  31  to the secondary transfer position  20  again, whereby a double-sided printing operation is achieved. 
     Double-sided printing circulation control is performed using the conveying paths including the double-sided printing conveying path  31 , the secondary transfer position  20 , and the fixing device  22 . Five-sheet circulation control is performed for A-4 size sheets and LTR size sheets, and three-sheet circulation control is performed for sheets having a size larger than the A-4 and LTR sizes. 
     Next, a description will be given of an operation performed by the finisher  109  as a creation unit configured to create a fold section (signature). The finisher  109  performs post-processing on a sheet according to settings designated by the user. More specifically, the finisher  109  has functions of stapling (one-point stapling/two-point stapling), punching (two-hole punching/three-hole punching), and saddle-stitch processing. 
     The finisher  109  appearing in  FIG. 1  includes discharge trays  28 ,  29 , and  30 , and a sheet having passed through the discharge outlet  24  which guides a sheet to the finisher  109  is discharged onto one of the discharge trays associated with the respective functions of copying, printing, and facsimile, according to a setting designated by the user. 
     When the sheet processing apparatus  90  is used as a printer, various settings, such as settings for monochrome printing, color printing, a sheet size, 2-up/4-up printing/N-up printing, double-sided printing, stapling, punching, saddle-stitching, a lining board, a cover, and a back cover, can be made using a driver. 
     Next, a description will be given of the construction and operation of the finisher  109  appearing in  FIG. 1  with reference to  FIGS. 2 to 7 . 
     In  FIG. 2 , the finisher  109  includes conveying rollers  61  to  69 , leading edge detection sensors  50  and  53 , a skew correction roller  51 , a loop space  52 , a conveying path  71 , a stapler  72 , a thrusting plate  73 , a stopper  74 , folding rollers  75  and  76 , and bundle conveying roller pairs  77  and  78 . Further, S denotes a sheet. 
     The finisher  109  may be operated according to commands from the controller unit  100  of the sheet processing apparatus  90 , or may be operated by a controller unit of its own. 
     A sheet conveyed from the sheet processing apparatus  90  is discharged onto one of the discharge trays  28 ,  29 , and  30  according to a type of sheet processing set by the user. 
     For example, when sheet processing is not executed, the sheet is discharged onto the discharge tray  28 . When normal staple processing is executed, the sheet is discharged onto the discharge tray  29 , and when saddle-stitch bookbinding processing or center-fold bookbinding processing is executed, the sheet is discharged onto the discharge tray  30 . Note that center-fold bookbinding processing includes center-fold processing and saddle-stitch bookbinding processing includes center-fold processing and saddle-stitch processing. 
     The sheet conveyed from the sheet processing apparatus  90  is conveyed by the conveying rollers  61  to  68  until a leading edge of the sheet reaches the leading edge detection sensor  50 . Then, as shown in  FIG. 3 , when the leading edge of the sheet is detected by the leading edge detection sensor  50 , a speed of the conveying roller  68  nipping the sheet is reduced, and the leading edge of the sheet is brought into abutment with a nip of the skew correction roller  51 . 
     Even after the leading edge of the sheet has been brought into abutment with the nip of the skew correction roller  51 , the conveying roller  68  continues to be rotated for a while. Then, the sheet forms a loop or bend in the loop space  52 , and then the conveying roller  68  is stopped. 
     Next, the skew correction roller  51  starts rotation thereof. If the sheet is skewed, the skew is corrected by the skew correction roller  51 . The sheet subjected to skew correction is conveyed toward the conveying roller  69 . 
     Then, as shown in  FIG. 4 , the sheet is conveyed by a predetermined amount from the time point when the leading edge of the sheet is detected by the leading edge detection sensor  53 , whereby the leading edge of the sheet is brought into abutment with a stopper  74   a.    
     At this time, as shown in  FIG. 4 , the sheet is positioned by the stopper  74   a  such that a stapling position to be stapled by the stapler  72  is arranged in the center of the sheet. By repeating the above-described operation, a plurality of sheets are sequentially conveyed into the conveying path  71 . 
     Then, when all of sheets forming a booklet have been conveyed into the conveying path  71 , these sheets are aligned in a direction of the width thereof by a width direction-aligning plate, not shown, and as shown in  FIG. 5 , a sheet bundle  81  is formed within the conveying path  71 . 
     At this time, the sheets to be conveyed into the conveying path  71  are sequentially conveyed in such a manner that a sheet material to be set at the innermost location of the booklet is first conveyed, and a cover of the booklet is finally conveyed. 
     Further, when the settings are made such that saddle-stitch bookbinding processing is to be performed, the stapler  72  performs binding processing on the sheet bundle  81 . When the sheet bundle  81  has been bound or stapled by the stapler  72 , the stopper  74   a  having supported the sheet bundle  81  is moved downstream in a conveying direction, and serves as a stopper  74   b  as shown in  FIG. 5 . 
     The sheet bundle  81  is moved downstream in the conveying direction in accordance with the movement of the stopper. On the other hand, when the settings are not made such that saddle-stitch bookbinding processing is to be performed, but are made such that center-fold bookbinding processing is to be performed, the stopper is positioned at a location of the stopper  74   b  from the start of conveying the sheets, and stapling by the stapler  72  is omitted. 
     The stopper  74   b  positions the sheet bundle  81  such that the center of the sheet bundle  81  is arranged at a location of the thrusting plate  73 . Then, a front end of the thrusting plate  73  is brought into abutment with a portion of the sheet bundle  81  positioned by the stopper  74   b , where a fold line is to be formed, and as shown in  FIG. 6 , the sheet bundle is thrust in a nip between the folding rollers  75  and  76  to thereby form a fold line on the sheet material. 
     The sheet bundle  81  folded and formed with the fold line by the folding rollers  75  and  76  is discharged onto the discharge tray  30  by the bundle conveying roller pairs  77  and  78  as shown in  FIG. 7 . 
     When conveying the folded sheet bundle  81  by the bundle conveying roller pairs  77  and  78 , if binding processing (stapling) has been executed, the sheet bundle has been bound, and hence the sheet bundle is stably conveyed. 
     However, in a case where binding processing has not been executed, when a plurality of sheets are conveyed in a folded state, if the number of sheets is large, the sheet bundle is conveyed with lower stability than the case where binding processing has been executed. As the number of sheets included in a sheet bundle is larger, the stability of the conveyed sheets becomes lower, and a paper jam is more likely to occur due to a jam of a displaced sheet in a conveying path. 
       FIG. 8  is a diagram showing the electrical configuration of the sheet processing apparatus  90  according to the first embodiment of the present invention. 
     In  FIG. 8 , the sheet processing apparatus  90  includes the controller unit  100  that controls the overall operation of the sheet processing apparatus  90 , the finisher  109  that performs post-processing, and the scanner  119  as an image input device. The sheet processing apparatus  90  further includes the printer engine  120  as an image output device, and a console section  121  used for inputting instructions from an operator and displaying information to the operator. 
     The finisher  109 , the scanner  119 , the printer engine  120 , and the console section  121  are connected to the controller unit  100 , and are controlled according to instructions from the controller unit  100 . The scanner  119  is connected to a scanner image processing section  117  of the controller unit  100 , and the printer engine  120  is connected to a printer image processing section  118  of the controller unit  100 . 
     The controller unit  100  includes a CPU  101 . The CPU  101  is connected to the RAM  102 , a ROM  103 , an HDD  104 , an image bus interface  105 , a console section interface  106 , an accessory interface  108 , and a network interface  107 , via a system bus  110 . 
     The RAM  102  is a memory for providing a work area for the CPU  101 . The RAM  102  is used as a set value-storing memory for temporarily storing parameter setting values, and an image memory for storing part of image data. 
     The ROM  103  is a boot ROM which stores a system boot program. The HDD  104  stores system software, history of the parameter setting values, image data, and so on. 
     The CPU  101  is capable of loading the system boot program stored in the ROM  103  into the RAM  102 . By thus loading the system boot program in the RAM  102 , the CPU  101  becomes capable of executing a controller program. 
     The console section interface  106  is an interface for inputting and outputting information and data to and from the console section  121 . The console section interface  106  outputs image data to be displayed to the console section  121  according to instructions from the CPU  101 , and transfers information input by the operator via the console section  121  to the CPU  101 . 
     The accessory interface  108  is connected to the finisher  109 , and transfers data of a type of post-processing, set values, adjustment values, and a device status, to the finisher  109  according to instructions received from the CPU  101 . The finisher  109  is a device for performing post-processing, and the types of the finisher to be connected include a stapling unit, a folding machine, and a puncher. 
     The network interface  107  is connected to a LAN  122 , and performs inputting and outputting of information to and from the LAN  122 . 
     The image bus interface  105  is a bus bridge that connects between the system bus  110  and an image bus  111 , and converts data structure. A RIP  112  rasterizes a PDL code received from the LAN  122  into a bitmap image. An image-editing image processing section  114  performs image processing on data of original images read by the scanner  119  or stored in the HDD  104 . 
     An image expansion section  115  decodes and expands image data stored in the HDD  104  in a compressed and encoded state before the image data is subjected to image processing by the printer image processing section  118  and is then output to the printer engine  120 . 
     Further, an image compression section  116  encodes image data processed by the RIP  112  and the scanner image processing section  117  by a predetermined compression method before storing the same in the HDD  104 . 
     The device interface  113  is connected to the scanner  119  and the printer engine  120  via the scanner image processing section  117  and the printer image processing section  118 , respectively, and performs synchronous-to-asynchronous or asynchronous-to-synchronous conversion of image data, and transfer of data of set values, adjustment values, and a device status. 
     The scanner image processing section  117  performs various kinds of processing, including correction, processing, image area separation, scaling, binarization, and other editing processing, on image data input from the scanner  119 . 
     The scanner  119  is capable of reading both sides of each of a plurality of originals as described with reference to  FIG. 1 . Further, as described with reference to  FIG. 1 , the scanner  119  includes the sensors for detecting opening/closing of the document feeder  2 , presence of an original, and a size of an original. The detected information and the status information of the scanner  119  are sent to the CPU  101  via the scanner image processing section  117  and the device interface  113 . 
     The printer image processing section  118  performs processing on image data to be printed out, such as correction and resolution conversion dependent on the printer engine  120 , and adjustment of print position of an image. 
     Further, the sheet feed cassettes  18  described with reference to  FIG. 1  each detect a size of sheets stored therein, and notifies the CPU  101  of the detected size via the printer engine  120 , the printer image processing section  118 , and the device interface  113 . 
     Further, device status information indicative of the remaining amount of sheets in each sheet feed cassette  18 , an opened/closed state of each cassette, etc., is sent to the CPU  101  via the printer image processing section  118  and the device interface  113 . 
       FIG. 9  is a diagram showing software module configuration of the sheet processing apparatus  90  according to the first embodiment. 
     The software modules shown in  FIG. 9  are mainly operated on the CPU  101 . A job control processing section  201  controls the software modules shown or not shown in  FIG. 9 , and controls every job generated in the sheet processing apparatus  90 , such as a copy job, a print job, a scan job, and a user interface processing job. 
     An user interface processing section  202  performs control associated mainly with the console section  121  and the console section interface  106 . The user interface processing section  202  notifies the job control processing section  201  of a user&#39;s operation using the console section  121 , and controls contents to be displayed on a display screen of the console section  121  based on instructions from the job control processing section  201 . The user interface processing section  202  further controls editing of image data to be displayed on the console section  121 . 
     A network processing section  203  is a module for controlling external communication mainly via the network interface  107 , and controls communication with the apparatuses on the LAN  122 . 
     When the network processing section  203  receives a control command or data from each apparatus on the LAN  122 , the network processing section  203  notifies the job control processing section  201  of the received contents. Further, the network processing section  203  transmits a control command or data to each apparatus on the LAN  122  based on instructions from the job control processing section  201 . 
     A RIP processing section  204  performs interpretation of a PDL (page description language) based on instructions from the job control processing section  201 , and causes the RIP  112  to perform rendering to thereby rasterize PDL data into a bitmap image. 
     A finishing processing section  205  controls the finisher  109  based on instructions from the job control processing section  201  to perform control of sheets and finishing processing on the sheets by the finisher  109 . Further, the finishing processing section  205  acquires status information of the finisher  109 , and notifies the job control processing section  201  of the acquired status information. 
     An image-editing processing section  206  controls the image-editing image processing section  114  based on instructions from the job control processing section  201  to thereby perform image processing on a designated image. 
     The image-editing processing section  206  receives image data, and image information indicative of a size, a color mode, and resolution of the image data, from the job control processing section  201 . Then, the image-editing processing section  206  controls the image-editing image processing section  114 , the image expansion section  115 , and the image compression section  116 , to thereby perform proper image processing on the image data, and notifies the job control processing section  201  of the processed image. 
     A scanning processing section  207  controls the scanner  119  and the scanner image processing section  117  based on instructions from the job control processing section  201  to thereby read an original set on the scanner  119 . 
     Then, the scanning processing section  207  instructs the scanner image processing section  117  to perform image processing on the read original image. Further, the scanning processing section  207  acquires status information of the scanner image processing section  117  and the scanner  119 , and notifies the job control processing section  201  of the acquired information. 
     A printing processing section  208  controls the image-editing image processing section  114 , the printer image processing section  118 , and the printer engine  120 , based on instructions from the job control processing section  201 , to thereby perform printing processing on a designated image. 
     The printing processing section  208  receives image data, and information, such as the above-mentioned image information, layout information, and output sheet information, from the job control processing section  201 . The layout information is information indicative of offset, scaling, imposition, and so on. Further, the output sheet information is information indicative of a size, a printing direction, and so on. 
     Then, the printing processing section  208  controls the image expansion section  115 , the image compression section  116 , the image-editing image processing section  114 , and the printer image processing section  118 , to thereby perform proper image processing on the image data, and controls the printer engine  120  to thereby print the processed image data on a printing sheet. 
     The printing processing section  208  controls the printer image processing section  118  and the printer engine  120  to thereby perform printing on a printing sheet. Further, the printing processing section  208  acquires status information of the printer image processing section  118  and the printer engine  120 , and notifies the job control processing section  201  of the acquired information. 
       FIGS. 10A to 10F  are schematic diagrams of screens which are displayed on the console section  121  appearing in  FIG. 8 . 
       FIG. 10A  shows a creep correction screen  300 .  FIG. 10B  shows a bookbinding setting screen  310 .  FIG. 10C  shows a sheet selection screen  330  used in the copy function.  FIG. 10D  shows a print position adjustment screen  340 .  FIG. 10E  shows a bookbinding lap adjustment screen  350 .  FIG. 10F  shows a folding position fine adjustment screen  360 . 
     Note that although an example using the settings for the copy function will be described hereafter, it is assumed that there are screens for configuring settings for similar functions of a print job to the above. When a print job is input from an information processing apparatus, not shown, via the LAN  122 , settings made on associated screens for setting the respective functions for the print job are made effective. 
     Upon receipt of a request for using a creep correction function from an operator via the console section  121 , the creep correction screen  300  shown in  FIG. 10A  is displayed in a manner switched from a standby screen, not shown. The creep correction screen is a screen used for configuring how to perform creep correction and setting a correction amount. 
     The creep correction function is a function for automatically shifting a print position, by taking into consideration that when sheets for bookbinding printing are stacked and folded, an inner sheet protrudes more outward than an outer sheet, depending on the thickness of each sheet. By using the creep correction function, printing is performed in such a manner that spacing between pages to be printed on one side of a sheet is gradually reduced as the sheet is a more inner one. 
     Finally, the sheets are trimmed such that the protruding portions are cut off. The creep correction function is enabled only when a button  311  named as “execute bookbinding imposition” is selected in  FIG. 10B , described hereinafter, and at the same time a sheet to be used enables bookbinding imposition. 
     Buttons  301  and  302  are used for selecting a method of determining a correction amount. The button  301  named as “use setting for sheet” is button for selecting application of a creep correction amount set for sheets from a detailed sheet settings screen, not shown. 
     In a state where the button  301  is selected, the operator cannot input an adjustment amount for creep correction from the creep correction screen  300  which is displayed. The user sets a creep correction amount for a sheet type from the detailed sheet settings screen, not shown, in a state where the “use setting for sheet” button  301  is selected and stored. Further, when the user selects the sheet type to which the creep correction amount is set as a type of sheets to be used, from the screen shown in  FIG. 10C , referred to hereinafter, the creep correction is enabled. 
     The button  302  named as “specify value” is used to select specifying a creep correction amount, and when the user selects the button  302 , a plus button  304  and a minus button  303  are made selectable. 
     Although the creep correction amount specified here is a length of shift between an outermost sheet and an innermost sheet of a finished book, a correction amount per one sheet may be set as the creep correction amount. The plus button  304  and the minus button  303 , or a numerical keyboard, not shown, included in the console section  121  are/is used to specify the creep correction amount. 
     Only one of the “use setting for sheet” button  301  and the “specify value” button  302  can be set to the selected state. When the operator selects the “specify value” button  302  after selecting the “use setting for sheet” button  301 , the “use setting for sheet” button  301  is released from the selected state, and the “specify value” button  302  is set to the selected state. This applies vice versa. 
     In a state where the “specify value” button  302  is selected, the minus button  303  and the plus button  304  are placed in an enabled state enabling the operator to operate them. When the minus button  303  or plus button  304  is operated on the creep correction screen  300 , a value of the creep correction amount is entered. 
     When the minus button  303  is operated on the creep correction screen  300 , the creep correction amount is temporarily decremented, and the displayed creep correction amount is updated. 
     When the plus button  304  is operated on the creep correction screen  300 , the creep correction amount is temporarily incremented, and the displayed creep correction amount is updated. 
     Further, when the minus button  303  and the plus button  304  are in the enabled state, the operator may perform the creep correction by entering a value using the numerical keyboard, not shown, included in the console section  121 . 
     A cancel button  305  aborts the creep correction setting. When the cancel button  305  is operated on the creep correction screen  300 , the creep correction setting information which has been temporarily stored is abandoned, and the standby screen is displayed. 
     A return button  306  terminates the creep correction setting. When the return button  306  is operated on the creep correction screen  300 , the standby screen is displayed without temporarily storing the creep correction setting information. 
     An OK button  307  completes the creep correction setting. In a state where one of the “use setting for sheet” button  301  and the “specify value” button  302  is selected, the operator can select the OK button  307 . 
     When neither the “use setting for sheet” button  301  nor the “specify value” button  302  is set, the OK button  307  is not enabled. 
     Further, when the OK button  307  is operated on the creep correction screen  300 , the method of setting a creep correction amount according to a selected one of the “use setting for sheet” button  301  and the “specify value” button  302  is temporarily stored, and the standby screen is displayed. Further, if the “specify value” button  302  has been selected, the set creep correction amount is temporarily stored, and the standby screen is displayed. 
     The bookbinding setting screen  310  shown in  FIG. 10B  is an example of a screen used for configuring settings for printing and settings for finishing, so as to perform bookbinding printing according to a copy job. 
     Setting items for bookbinding include three items for setting whether bookbinding imposition is to be executed, whether folding in the middle of a print product is to be executed after printing, and whether stitching in the middle of a print product is to be executed after printing, as well as items for setting a cover, setting a direction of opening a finished book, and so forth. These items can be set in combination. 
     Note that imposition refers to the laying out of pages for printing. If normally scanned images are printed in the scanned order, the printed pages are not in a proper order in a saddle-stitched book. A function for performing printing such that the saddle-stitched book has a correct page order is referred to as the bookbinding imposition function. 
     The “execute bookbinding imposition” button  311  and an “inhibit bookbinding imposition” button  312  are used to select whether or not to use the bookbinding imposition function. 
     The “execute bookbinding imposition” button  311  is set to a selected state when the operator operates the “execute bookbinding imposition” button  311 . If the settings are stored when the “execute bookbinding imposition” button  311  is in the selected state, bookbinding imposition is performed for copy jobs to be executed thereafter. The operator has to select sheets having a size which enables bookbinding imposition in association with read original sheets, from the sheet selection screen shown in  FIG. 10C , referred to hereinafter. 
     The “inhibit bookbinding imposition” button  312  is set to a selected state when the operator operates the “inhibit bookbinding imposition” button  312 . If the settings are stored when the “inhibit bookbinding imposition” button  312  is in the selected state, copy jobs to be executed thereafter are executed without performing bookbinding imposition. 
     When the operator desires to perform bookbinding using a center-folding function, referred to hereinafter, without performing bookbinding imposition, originals read by the scan operation has to be originals on which bookbinding imposition has been performed. 
     Only one of the “execute bookbinding imposition” button  311  and the “inhibit bookbinding imposition” button  312  can be set to the selected state. If the operator selects the “inhibit bookbinding imposition” button  312  after selecting the “execute bookbinding imposition” button  311 , the “execute bookbinding imposition” button  311  is released from the selected state, and the “inhibit bookbinding imposition” button  312  is set to the selected state. This applies vice versa. 
     Finishing processing to be performed on print products after printing is selected through operation of buttons  313  to  315  by the operator. 
     Of the button  313  named as “folding+saddle-stitching”, the button  314  named as “non-folding”, and the button  315  named as “folding only”, buttons which the operator can operate are limited by the capabilities of the finisher  109  connected to the sheet processing apparatus  90  via the accessory interface  108 . 
     The CPU  101  acquires capability information of the connected finisher  109  via the accessory interface  108 . If the CPU  101  determines based on the acquired capability information that the finisher  109  is capable of performing center-fold processing, the CPU  101  makes the “folding only” button  315  selectable. 
     Further, if the CPU  101  determines that the finisher  109  is capable of performing saddle-stitch processing for stapling sheets in the middle, the CPU  101  makes the “folding+saddle-stitching” button  313  selectable. If the CPU  101  determines that the finisher  109  is not capable of performing center-fold processing, the CPU  101  makes only the “non-folding” button  314  selectable. 
     The “folding+saddle-stitching” button  313  is set to a selected state when the operator operates the “folding+saddle-stitching” button  313 . If the settings are stored when the “folding+saddle-stitching” button  313  is in the selected state, center-fold processing and saddle-stitch processing are performed for copy jobs to be executed thereafter. The operator has to select sheets which enable center-fold processing and saddle-stitch processing, from the sheet selection screen shown in  FIG. 10C , referred to hereinafter. 
     Depending on the number of sheets of a print product, there is a case where at least one of center-fold processing and saddle-stitch processing cannot be performed. This determination is performed by the CPU  101 , and the copy job is cancelled or terminated without performing center-fold processing or saddle-stitch processing. 
     The “non-folding” button  314  is set to a selected state when the operator operates the “non-folding” button  314 . If the settings are stored when the “non-folding” button  314  is in the selected state, neither center-fold processing nor saddle-stitch processing is performed for copy jobs to be executed thereafter. 
     The “folding only” button  315  is set to a selected state when the operator operates the “folding only” button  315 . If the settings are stored when the “folding only” button  315  is in the selected state, center-fold processing is performed for copy jobs to be executed thereafter. The operator has to select sheets which enable center-fold processing, from the sheet selection screen shown in  FIG. 10C , referred to hereinafter. 
     Depending on the number of sheets of a print product, there is a case where center-fold processing cannot be performed. This determination is performed by the CPU  101 , and if it is determined that center-fold processing cannot be performed, the copy job is cancelled or terminated without performing center-fold processing. 
     As described hereinbefore, center-fold processing is a function used also in a case where binding processing is performed using another system (off-line apparatus) which is different from the sheet processing apparatus  90 , from the viewpoints of productivity, quality, and binding performance. In a case where binding processing is executed for bookbinding, opposite ends of sheets, which are to form a fore edge of a book, referred to hereinafter, are required to be made different in position when the sheets are folded. The difference in position of the opposite ends, i.e. opposite fore edge portions, of each folded sheet (a distance between a first sheet end and a second sheet end of each sheet assumed to have been folded in two) is generally referred to as the lap. The lap can be set using the screen shown in  FIG. 10E , referred to hereinafter. 
     Only one of the “folding+saddle-stitching” button  313 , the “non-folding” button  314 , and the “folding only” button  315  can be set to the selected state. When the operator operates another button when one of the above-mentioned buttons is in the selected state, the button which has been selected is released from the selected state, and then the button which the operator has newly operated is set to the selected state. 
     When the operator operates a cover setting button  316 , the screen is shifted to a cover setting screen, not shown, for configuring the settings of a cover. On the cover setting screen, it is possible to set a printing side of a sheet for a page corresponding to a cover of a finished book, and a printing sheet separately from the settings of text of the book. 
     When the operator operates an opening direction button  317 , the screen is shifted to an opening direction-setting screen, not shown, for setting a direction of opening a finished book (binding direction). On the opening direction-setting screen, the operator can operate the cover setting button  316  only when the “execute bookbinding imposition” button  311  has been selected. When the “execute bookbinding imposition” button  311  has not been selected, even if the operator has set the opening direction on the cover setting screen in advance, the CPU  101  disables the setting of the opening direction. 
     When the operator operates a detailed settings button  318 , the screen is shifted to a detailed settings screen, not shown, for configuring other detailed bookbinding settings. 
     A cancel button  319  is used for aborting the bookbinding setting. When the operator operates the cancel button  319 , the bookbinding setting information which has been temporarily stored is abandoned, and the standby screen is displayed. 
     A return button  320  is used for terminating the bookbinding setting. When the operator operates the return button  320 , the standby screen is displayed without temporarily storing the bookbinding setting information. 
     An OK button  321  is used for completing the bookbinding setting. The operator can operate the OK button  321  in a state where one of the “execute bookbinding imposition” button  311  and the “inhibit bookbinding imposition” button  312 , and one of the “folding+saddle-stitching” button  313 , the “non-folding” button  314 , and the “folding only” button  315  are selected. 
     When neither the “execute bookbinding imposition” button  311  nor the “inhibit bookbinding imposition” button  312  is selected, or neither the “folding+saddle-stitching” button  313  nor “non-folding” button  314  nor the “folding only” button  315  is selected, the OK button  321  cannot be operated. 
     When the operator operates the OK button  321 , information on the selected ones of the buttons  311  to  315 , indicating that those buttons have been selected, is temporarily stored. 
     Further, the settings configured on the cover setting screen, the opening direction-setting screen, and the detailed settings screen, none of which are shown, are similarly stored, and the standby screen is displayed. 
     The sheet selection screen  330  shown in  FIG. 10C  is displayed for indicating sheet sizes and sheet types currently set to the respective sheet feed cassettes  18  provided in the printer engine  120 , and enabling the operator to set output sheet size and type information for printing. 
     The output sheet size information indicates regular sheet sizes, such as A4, A3, B4, B5, and Letter, and an irregular sheet size which is input by the operator on an irregular size input screen, not shown, via the console section  121 , and each sheet size is associated with a longitudinal length and a lateral length. 
     Further, the sheet type information indicates two kinds of sheet types: a sheet type stored in an area of the HDD  104  of the sheet processing apparatus in advance, and a sheet type input by the operator on a sheet type registration screen via the console section  121  and stored in an area of the HDD  104 . 
     The sheet type information includes information on a weight per unit area of a sheet, surface properties, such as matte paper, glossy paper, and plain paper, and a shape, such as an index sheet and an envelope. The above-mentioned information is used to perform printing by the printer engine  120  according to the optimum settings for a sheet. 
     An automatic setting button  331  is used for specifying that output sheet setting is to be automatically performed according to the size of an original image for printing and the print settings. When the operator operates the automatic setting button  331 , the output sheet setting is performed by an output sheet-setting process, described hereinafter. The automatic setting button  331  is set to a selected state when the operator operates the automatic setting button  331 . 
     Sheet setting buttons  332  are associated with the sheet feed cassettes  18 , respectively, which are held in the printer engine  120 . The sheet setting buttons  332  are displayed in number corresponding to the number of sheet feed cassettes which varies with the configuration of the sheet processing apparatus  90 . 
     In this example, the printer engine  120  includes four sheet feed cassettes  18 , and hence the four sheet setting buttons  332  are displayed. 
     The settings information stored in the RAM  102  includes sheet size information and sheet type information set as the sheet size and sheet type of sheets contained in each sheet feed cassette  18 . The sheet size information and the sheet type information set as the sheet size and the sheet type, respectively, are set by the operator via the console section  121 . Alternatively, in a case where each sheet feed cassette  18  has a function for automatically detecting a sheet size, the detected size is notified to the CPU  101  via the printer engine  120 , the printer image processing section  118 , and the device interface  113 , as the sheet size information, and then set as the sheet size. 
     Further, when it is detected that any of the sheet feed cassettes  18  contains no sheets, the CPU  101  receives no-sheet information, and sets one of the sheet setting buttons  332  associated with the corresponding sheet feed cassette to a non-selectable state. 
     On each sheet setting button  332 , the output sheet size information and output sheet type information set to an associated one of the sheet feed cassettes  18 , and a rough indication of a remaining amount of sheets in the associated one of the sheet feed cassettes  18 , which is detected by the sheet feed cassette, are displayed. 
     The rough indication of the remaining amount of sheets is set by notifying the CPU  101  of the remaining amount via the printer engine  120 , the printer image processing section  118 , and the device interface  113 . 
     Each sheet setting button  332  is set to the selected state when the operator operates the sheet setting button  332  in a state where the sheet setting button  332  is in the selectable state. 
     Only one of the automatic setting button  331  and the sheet setting buttons  332  is set to the selected state. As far as the selected state is concerned, the automatic setting button  331  is regarded as one of the sheet setting buttons  332 , and operates similarly to the sheet setting buttons  332 . 
     After one of the sheet setting buttons  332  has been selected, if another sheet setting button  332  is selected, the one sheet setting button  332  which has been selected is released from the selected state, and the another sheet setting button  332  which is newly selected is set to the selectable state. 
     A details button  333  can be selected only in a state where one of the sheet setting buttons  332  is selected, and cannot be selected when the automatic setting button  331  is selected. 
     When the operator operates the details button  333  in the selectable state, a sheet type details screen, not shown, for displaying sheet type information set to one of the sheet feed cassettes  18  associated with the sheet setting button  332  selected at that time is displayed. 
     This screen displays associated sheet type information stored in the HDD  104  as the sheet type information, and the operator can change the registered sheet type information, as required, by operating the console section  121 . 
     A cancel button  334  is used for aborting the output sheet selection. When the operator operates the cancel button  334 , the standby screen is displayed without temporarily storing the output sheet information. 
     An OK button  335  is used for completing the output sheet selection. The operator can operate the OK button  335  when the automatic setting button  331  or one of the sheet setting buttons  332  is in the selected state. 
     The OK button  335  cannot be operated when neither the automatic setting button  331  nor one of the sheet setting buttons  332  is in the selected state. When the operator operates the OK button  335 , information indicative of the output sheet size and type, associated with the selected button, is temporarily stored in the setting information in the RAM  102  as the output sheet information in the copy settings, and the standby screen is displayed. 
     The print position adjustment screen  340  shown in  FIG. 10D  is displayed for enabling the operator to perform adjustment of a print position for a copy job. 
     The print position adjustment is a function for setting layout by shifting the position of an original image with respect to an output sheet. A front side button  341  and a reverse side button  342  are used to select whether or not to set a set value used in printing of a front side of a sheet, and whether or not to set a set value used in printing of a reverse side of the sheet, respectively. 
     Shift direction designation buttons  343 ,  344 ,  345 , and  346  are associated with upward, leftward, rightward, and downward directions respectively. 
     When the front side button  341  or the reverse side button  342  is operated for selection, the button operated by the operator is set to a selected state. Only one of the front side button  341  and the reverse side button  342  is set to the selected state. After one of the front side button  341  and the reverse side button  342  has been selected, if the other is selected, the precedingly selected button is released from the selected state, and the newly selected button is set to the selected state. 
     The operator can operate the shift direction designation buttons  343 ,  344 ,  345 , and  346  when the front side button  341  or the reverse side button  342  is in a selected state. If the operator operates any of the shift direction designation buttons  343 ,  344 ,  345 , and  346  in this state, the operated shift direction designation buttons  343 ,  344 ,  345 , and  346  is set to the selected state. In a state where neither the front side button  341  nor the reverse side button  342  is selected, none of the shift direction designation buttons  343 ,  344 ,  345 , and  346  can be operated. 
     Only one of the shift direction designation buttons  343 ,  344 ,  345 , and  346  is set to the selected state. After one of the shift direction designation buttons  343 ,  344 ,  345 , and  346  has been selected, if another one is selected, the precedingly selected shift direction designation button is released from the selected state, and the newly selected shift direction designation button is set to the selected state. 
     The operator can input a shift amount by operating the numerical keyboard, not shown, included in the console section  121 , when one of the shift direction designation buttons  343 ,  344 ,  345 , and  346  is in the selected state. 
     When the numerical keyboard is operated, the shift amount in a direction corresponding to the selected printing side and shift direction designation button is temporarily changed, and the displayed shift amount is updated. 
     A cancel button  347  is used for aborting the print position adjustment. When the operator operates the cancel button  347 , the temporarily stored print position adjustment is abandoned, and the standby screen is displayed. 
     A return button  348  is used for terminating the print position adjustment. When the operator operates the return button  348 , the standby screen is displayed without temporarily storing the print position adjustment. 
     An OK button  349  is used for completing the print position adjustment. The operator can operate the OK button  349  when one of the front side button  341  and the reverse side button  342  and one of the shift direction designation buttons  343 ,  344 ,  345 , and  346  are in the selected state. 
     When neither the front side button  341  nor the reverse side button  342  is in the selected state, or none of the shift direction designation buttons  343 ,  344 ,  345 , and  346  is in the selected state, the OK button  349  cannot be operated. When the operator operates the OK button  349 , the side of a sheet to be subjected to the print position adjustment, the shift direction, and the shift amount are temporarily stored, and the standby screen is displayed. 
     The bookbinding lap adjustment screen  350  shown in  FIG. 10E  is displayed for enabling the operator to perform bookbinding lap adjustment for a copy job. 
     The bookbinding lap adjustment is, as mentioned above, a function for adjusting a lap which is a difference in position of opposite ends, i.e. opposite fore edge portions, of sheets, which are to form the fore edge of a book, provided when the sheets are folded. The lap is necessary when binding processing is executed for bookbinding printing processing. 
     A minimum necessary lap is approximately 5.0 mm, and a lap of approximately 10 mm is considered as a most preferable lap. The bookbinding lap adjustment set on the screen shown in  FIG. 10E  is enabled only when a copy job is executed in a state where the “folding only” button  315  has been selected and stored for the finishing processing function shown in  FIG. 10B . 
     When the operator operates a minus button  352  and a plus button  353 , a bookbinding lap adjustment value is set. 
     When the operator operates the minus button  352 , the bookbinding lap adjustment value is temporarily incremented, and the displayed bookbinding lap adjustment value is updated. 
     When the operator operates the plus button  353 , the bookbinding lap adjustment value is temporarily decremented, and the displayed bookbinding lap adjustment value is updated. 
     When the operator operates a plus-minus button  351 , the sign of the bookbinding lap adjustment value is reversed, and the displayed bookbinding lap adjustment value is updated. 
     Further, in a state where the screen shown in  FIG. 10E  is displayed, the operator may set a bookbinding lap adjustment value using the numerical keyboard, not shown, included in the console section  121 . 
     Note that when the value of the bookbinding lap adjustment value is positive, it indicates a set value for advancing a fore edge portion of each sheet, which is associated with a larger page number of a finished book set to a left-to-right page layout, i.e. increasing the distance of the fore edge portion from the fold line of the sheet. The value thus set is generally referred to as a value of high lap. 
     On the other hand, when the value of the bookbinding lap adjustment value is negative, it indicates a set value for advancing a fore edge portion of the sheet, which is associated with a smaller page number of the finished book set to the left-to-right page layout, i.e. increasing the distance of the fore edge portion from the fold line of the sheet. The value thus set is generally referred to as a value of low lap. Note that when the finished book is set to a right-to-left page layout, the fore edge portions which are advanced according to the high lap and low lap, respectively, are opposite to the above. 
     A cancel button  354  is used for aborting the bookbinding lap adjustment. When the operator operates the cancel button  354 , the temporarily stored bookbinding lap adjustment is abandoned, and the standby screen is displayed. 
     A return button  355  is used for terminating the bookbinding lap adjustment. When the operator operates the return button  355 , the standby screen is displayed without temporarily storing the bookbinding lap adjustment. 
     An OK button  356  is used for completing the bookbinding lap adjustment. When the operator operates the OK button  356 , the bookbinding lap adjustment is temporarily stored, and the standby screen is displayed. 
     The folding position fine adjustment screen  360  shown in  FIG. 10F  is displayed for enabling the operator to performing folding position fine adjustment. 
     The folding position fine adjustment is a function for correcting a slight amount of erroneous shift of a folding position from the center of a sheet, caused by an error inherent to the sheet processing apparatus or variation between production lots of sheets. 
     When the operator operates a minus button  362  or a plus button  363 , a folding position fine adjustment value is set. 
     When the operator operates the minus button  362 , the folding position fine adjustment value is temporarily incremented, and the displayed folding position fine adjustment value is updated. 
     When the operator operates the plus button  363 , the folding position fine adjustment value is temporarily decremented, and the displayed folding position fine adjustment value is updated. 
     When the operator operates a plus-minus button  361 , the sign of the folding position fine adjustment value is reversed, and the displayed folding position fine adjustment value is updated. 
     Further, in a state where the screen shown in  FIG. 10F  is displayed, the operator may set a folding position fine adjustment value using the numerical keyboard, not shown, included in the console section  121 . 
     Note that a positive direction in the folding position adjustment is a direction of adjusting the folding position leftward and a negative direction is a direction of adjusting the folding position rightward, for bookbinding of a book set to a left-to-right page layout. 
     A cancel button  364  is used for aborting the folding position fine adjustment. When the operator operates the cancel button  364 , the temporarily stored folding position fine adjustment is abandoned, and the standby screen is displayed. 
     A return button  365  is used for terminating the folding position fine adjustment. When the operator operates the return button  365 , the standby screen is displayed without temporarily storing the folding position fine adjustment. 
     An OK button  366  is used for completing the folding position fine adjustment. When the operator operates the OK button  366 , the folding position fine adjustment is temporarily stored, and the standby screen is displayed. 
       FIG. 11  is a flowchart of a waiting-time process executed by the CPU  101  appearing in  FIG. 8 . 
       FIG. 11  shows the waiting-time process which is started upon receipt of a request for using a copy function from an operator. Although the description is given of a case of the copy function by way of example, a similar process is executed for a print job. 
     The CPU  101  displays the standby screen, not shown, on the console section  121  (step S 401 ), and waits until a button operation by the operator is received (step S 402 ). 
     Upon receipt of an operation from the operator in this state, the CPU  101  determines whether or not a creep correction setting button, not shown, has been operated (step S 403 ). 
     If it is determined in the step S 403  that the creep correction setting button has been operated (YES to the step S 403 ), the CPU  101  displays the creep correction screen  300  on the console section  121 . Then, the CPU  101  executes the creep correction setting process for accepting the creep correction operation performed by the operator (step S 404 ). 
     The creep correction process executed at this time has been described with reference to  FIG. 10A . When the creep correction setting is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 403  that the creep correction setting button has not been operated (NO to the step S 403 ), the CPU  101  determines whether or not a bookbinding setting button, not shown, has been operated (step S 405 ). 
     If it is determined in the step S 405  that the bookbinding setting button has been operated (YES to the step S 405 ), the CPU  101  displays the bookbinding setting screen  310  on the console section  121 , and executes the bookbinding setting process for accepting the bookbinding setting operation performed by the operator (step S 406 ). 
     The process executed at this time has been described with reference to  FIG. 10B . When the bookbinding setting is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 405  that the bookbinding setting button has not been operated (NO to the step S 405 ), the CPU  101  determines whether or not a print position adjustment button, not shown, has been operated (step S 407 ). 
     If it is determined in the step S 407  that the print position adjustment button has been operated (YES to the step S 407 ), the CPU  101  displays the print position adjustment screen  340  on the console section  121 . Then, the CPU  101  executes the print position adjustment setting process for accepting the print position adjustment setting operation performed by the operator (step S 408 ). 
     The process executed at this time has been described with reference to  FIG. 10C . When the print position adjustment setting is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 407  that the print position adjustment button has not been operated (NO to the step S 407 ), the CPU  101  determines whether or not an output sheet selection button has been operated (step S 409 ). 
     If it is determined in the step S 409  that the output sheet selection button has been operated (YES to the step S 409 ), the CPU  101  proceeds to a step S 410 . Then, the CPU  101  displays the sheet selection screen  330  on the console section  121 , and executes the output sheet-setting process for accepting the output sheet selection operation performed by the operator (step S 410 ). 
     The process executed at this time has been described with reference to  FIG. 10D . When the output sheet setting is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 409  that the output sheet selection button has not been operated (NO to the step S 409 ), the CPU  101  determines whether or not a bookbinding lap adjustment button, not shown, has been operated (step S 411 ). 
     If it is determined in the step S 411  that the bookbinding lap adjustment button has been operated (YES to the step S 411 ), the CPU  101  displays the bookbinding lap adjustment screen  350  on the console section  121 . Then, the CPU  101  executes the bookbinding lap adjustment process for accepting a bookbinding lap adjustment operation performed by the operator (step S 412 ). The step S 412  corresponds to the operation of a setting unit configured to set a bookbinding lap which is defined as a difference in distance from a fold line to opposite fore edge portions of each recording sheet of a fold section to be formed by forming the fold line on recording sheets having images formed thereon by the printer engine  120 , or a distance between opposite ends of each sheet assumed to have been folded in two. The finisher  109  forms a fold line on each recording sheet along a reference line shifted from the centerline indicative of a fold position in a case where no bookbinding lap is provided, by the bookbinding lap set in the step S 412 . 
     The process executed at this time has been described with reference to  FIG. 10E . When the bookbinding lap adjustment is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 411  that the bookbinding lap adjustment button has not been operated (NO to the step S 411 ), the CPU  101  determines whether or not a folding position fine adjustment button has been operated (step S 413 ). 
     If it is determined in the step S 413  that the folding position fine adjustment button has been operated (YES to the step S 413 ), the CPU  101  displays the folding position fine adjustment screen  360  on the console section  121 . Then, the CPU  101  executes the folding position fine adjustment process for accepting a folding position fine adjustment operation performed by the operator (step S 414 ). The step S 414  corresponds to the operation of a fine adjustment unit configured to finely adjust a position of a fold line formed by the finisher  109 . 
     The process executed at this time has been described using the folding position fine adjustment screen  360  with reference to  FIG. 10F . When the folding position fine adjustment is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 413  that the folding position fine adjustment button has not been operated (NO to the step S 413 ), the CPU  101  determines whether or not an other-function button has been operated (step S 415 ). Note that the other function refers to any print setting function other than the functions of creep correction, bookbinding setting, print position adjustment, output sheet setting, bookbinding lap adjustment, and folding position fine adjustment. 
     If it is determined in the step S 415  that the other-function button has been operated (YES to the step S 415 ), the CPU  101  displays a setting screen associated with the other function on the console section  121 . Then, the CPU  101  executes the other setting process for accepting an operation performed by the operator, for setting the other function (step S 416 ). A detailed description of the other setting process is omitted. When the other setting is accepted or canceled, the CPU  101  proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 415  that the other-function button has not been operated (NO to the step S 415 ), the CPU  101  determines whether or not a reset button, not shown, has been operated (step S 417 ). 
     If it is determined in the step S 417  that the reset button has been operated (YES to the step S 417 ), the CPU  101  executes a reset process for resetting all copy settings stored in the RAM  102  to initial values (step S 418 ), and proceeds to the step S 401 . 
     On the other hand, if it is determined in the step S 417  that the reset button has not been operated (NO to the step S 417 ), the CPU  101  determines whether or not a copy start button, not shown, has been operated (step S 419 ). 
     If it is determined in the step S 419  that the copy start button has been operated (YES to the step S 419 ), the CPU  101  proceeds to a scanning process shown in  FIG. 12 , followed by terminating the present process. On the other hand, if it is determined in the step S 419  that the copy start button has not been operated (NO to the step S 419 ), the CPU  101  proceeds to the step S 402 . 
       FIG. 12  is a flowchart of the scanning process executed by the CPU  101  appearing in  FIG. 8 . 
     In  FIG. 12 , the CPU  101  displays an original reading standby screen on the console section  121  (step S 501 ). 
     Next, the CPU  101  instructs the scanner  119  to start reading of an original to thereby read the original (step S 502 ). 
     Then, the CPU  101  performs image processing on the original image read by the scanner  119  (step S 503 ). Details of the image processing are determined based on the copy settings which have been set and temporarily stored according to the waiting-time process in  FIG. 11 . 
     The CPU  101  determines whether image processing on the read original image is to be performed by the scanner image processing section  117  or by the image-editing image processing section  114 , and instructs one of the scanner image processing section  117  and the image-editing image processing section  114 , which is determined by the CPU  101 , to perform image processing. 
     The CPU  101  checks whether or not an image processing completion notification has been received from the scanner image processing section  117  or the image-editing image processing section  114 , and until it is confirmed that the image processing completion notification has been received, the CPU  101  remains at the step S 503 . If it is confirmed that the image processing completion notification has been received, the CPU  101  proceeds to a step S 504 . 
     In the step S 04 , the CPU  101  instructs the image compression section  116  to compress the original image subjected to image processing in the step S 503 , and when image compression processing is completed, the CPU  101  stores the compressed original image in the HDD  104 . 
     When the original image has been stored, the CPU  101  acquires the size of the original image, i.e. the longitudinal and lateral sizes of the original image which has been subjected to image processing in the step S 503  (step S 505 ), and temporarily stores the acquired original image size. 
     When the original image size has been stored, the CPU  101  determines whether or not the scanner  119  has read all of the originals (step S 506 ). This is determined according to whether or not a notification indicative of completion of reading of the originals has been received from the scanner  119 . 
     If it is determined in the step S 506  that the scanner  119  has not read all of the originals (NO to the step S 506 ), the process returns to the step S 502 . 
     On the other hand, if it is determined in the step S 506  that the scanner  119  has read all of the originals (YES to the step S 506 ), the CPU  101  determines whether or not the output sheet setting is set to the automatic setting (step S 507 ). 
     If it is determined in the step S 507  that the output sheet setting is not set to the automatic setting (NO to the step S 507 ), the CPU  101  proceeds to a step S 510 . 
     On the other hand, if it is determined in the step S 507  that the output sheet setting is set to the automatic setting (YES to the step S 507 ), the CPU  101  executes an output sheet-setting process (step S 508 ). The output sheet-setting process will be described hereinafter with reference to the  FIG. 13 . 
     When the output sheet-setting process is terminated, the CPU  101  sets sheet settings associated with the sheet setting button in the selected state as the output sheet setting to thereby sets one of the sheet feed cassettes  18  selected by the operator for the output sheet (step S 509 ). 
     Next, the CPU  101  determines whether or not bookbinding setting has been made (step S 510 ). If it is determined in the step S 510  that the bookbinding setting has not been made (NO to the step S 510 ), the CPU  101  proceeds to a printing process, described hereinafter, with reference to  FIG. 15 . 
     On the other hand, if it is determined in the step S 510  that the bookbinding setting has been made (YES to the step S 510 ), the CPU  101  executes a bookbinding determination process based on the original image and the output sheet setting, and a capability value of the finisher  109  (step S 511 ). The bookbinding determination process will be described hereinafter with reference to  FIG. 14 . 
     When the bookbinding determination process is terminated, the CPU  101  determines whether or not bookbinding printing processing is determined to be executable by the bookbinding determination process in the step S 511  (step S 512 ). If it is determined in the step S 512  that bookbinding printing processing is determined to be executable (YES to the step S 512 ), the CPU  101  proceeds to the above-mentioned printing process. 
     On the other hand, if it is determined in the step S 512  that bookbinding printing processing is determined to be inexecutable (NO to the step S 512 ), the CPU  101  cancels the copy operation. Then, the CPU  101  instructs deletion of the original image stored in the HDD  104  in the step S 504  (step S 513 ), and deletes the setting information which has been temporarily internally stored. 
     Further, the CPU  101  notifies the scanner  119 , the printer engine  120 , and the console section  121  of cancellation of the copy operation, and proceeds to the step S 401  in  FIG. 11 , followed by terminating the present process. 
       FIG. 13  is a flowchart of the output sheet-setting process executed by the CPU  101  appearing in  FIG. 8 . 
     In the output sheet-setting process shown in  FIG. 13 , first, the CPU  101  calculates the size (resolution) of an original image to be printed based on the longitudinal and lateral sizes of the original image, which have been stored in the step S 505 , the print settings stored in the RAM  102 , and the print resolution of the printer engine  120 . 
     Then, the CPU  101  determines whether or not there is a sheet feed cassette set to a sheet size that enables printing of the original image of the calculated size. In addition, the CPU  101  determines whether or not the sheet type of the sheet feed cassette enables printing according to the print settings stored on the RAM  102 . 
     That is, the CPU  101  determines whether or not there is a sheet feed cassette  18  suitable for the print settings and the original image size (step S 601 ). 
     If it is determined in the step S 601  that there is a sheet feed cassette  18  suitable for the print settings and the original image size (YES to the step S 601 ), the CPU  101  proceeds to a step S 603 , wherein the CPU  101  selects the sheet feed cassette  18  set to the printable sheet size, which has been determined in the step S 601 , for the output sheet setting, followed by terminating the present process (step S 603 ). 
     On the other hand, if it is determined in the step S 601  that there is no sheet feed cassette  18  suitable for the print settings and the original image size (NO to the step S 601 ), the CPU  101  displays a warning on the console section  121 , indicating that there is no optimum sheet (step S 602 ). 
     Then, the CPU  101  waits until a button operation is performed by the operator (step S 604 ). More specifically, the CPU  101  checks whether or not the operator has operated the console section  121 , and if the operator has operated the console section  121 , the CPU  101  proceeds to a step S 605 , whereas if not, the CPU  101  remains at the step S 604 . 
     Then, the CPU  101  determines whether or not what the button operated in the step S 604  is a cancel button, not shown (step S 605 ). 
     If it is determined in the step S 605  that the button operated in the step S 604  is the cancel button (YES to the step S 605 ), the CPU  101  cancels the copy operation. Then, the CPU  101  instructs deletion of the original image stored in the HDD  104  in the step S 504  (step S 606 ), and deletes the setting information which has been temporarily stored therein. 
     Further, the CPU  101  notifies the scanner  119 , the printer engine  120 , and the console section  121  of cancellation of the copy operation, and proceeds to the step S 401  in  FIG. 11 , followed by terminating the present process. 
     On the other hand, if it is determined in the step S 605  that the operated button is not the cancel button (NO to the step S 605 ), the CPU  101  determines whether or not the button operated in the step S 604  is the output sheet selection button (step S 607 ). 
     If it is determined in the step S 607  that the operated button is the output sheet selection button (YES to the step S 607 ), the present process is terminated. On the other hand, if it is determined that the operated button is not the output sheet selection button (NO to the step S 607 ), the process returns to the step S 604 . 
       FIG. 14  is a flowchart of the bookbinding determination process executed by the CPU  101  appearing in  FIG. 8 . 
     In the bookbinding determination process shown in  FIG. 14 , the CPU  101  acquires the sheet size of the output sheet setting (step S 701 ). Next, the CPU  101  acquires the copy settings and output layout information which have been temporarily stored (step S 702 ). The output layout information indicates how an original image reference position is to be laid out with respect to the output sheet reference position. 
     Then, the CPU  101  acquires the original image size temporarily stored in the step S 505  (step S 703 ), and calculates, based on the copy settings, an original image size to be obtained after being subjected to image processing for printing. The CPU  101  temporarily stores the calculated original image size as an output-time original image size. 
     Next, the CPU  101  calculates a printable area based on the information acquired in the step S 702  and the output-time original image size (step S 704 ). The CPU  101  temporarily stores the calculated printable area in the RAM  102 . Then, the CPU  101  calculates the number of output pages based on the output layout information, the output-time original image size, and the printable area (step S 705 ). 
     Next, the CPU  101  acquires the temporarily stored finishing setting information (step S 706 ). 
     The CPU  101  determines, based on the information acquired in the step S 702  and the result calculated in the step S 703 , whether or not a combination of the original size and the sheet size is a printable combination (step S 707 ). Although this is determined according to the setting of whether or not to perform the bookbinding imposition, which has been described in detail with reference to  FIG. 10B , detailed description thereof is omitted. 
     If it is determined in the step S 707  that the combination of the original size and the sheet size is not a printable combination (NO to the step S 707 ), the CPU  101  determines that the bookbinding printing is not possible as a result of the bookbinding determination process (step S 714 ). Then, the CPU  101  temporarily stores the result that the bookbinding printing is not possible, followed by terminating the present process. 
     On the other hand, if it is determined in the step S 707  that the combination of the original size and the sheet size is a printable combination (YES to the step S 707 ), the CPU  101  determines, based on the information acquired in the step S 706 , whether or not center-fold processing is set (step S 708 ). Center-fold processing is performed according to the finishing setting of the bookbinding settings, described in detail with reference to  FIG. 10B . 
     If it is determined in the step S 708  that center-fold processing is not set (NO to the step S 708 ), the CPU  101  determines that the bookbinding printing is executable as a result of bookbinding determination processing (step S 713 ), and temporarily stores the result that the bookbinding printing is executable, followed by terminating the present process. 
     On the other hand, if it is determined in the step S 708  that center-fold processing is set (YES to the step S 708 ), the CPU  101  acquires the capability information of the finisher  109  via the accessory interface  108  (step S 709 ). The information acquired in the step S 709  includes the numbers, sizes, and types of sheets which can be subjected to center-fold processing, and further, the numbers, sizes, and types of sheets which can be subjected to saddle-stitch processing. 
     Next, the CPU  101  determines, based on the capability information of the finisher  109  acquired in the step S 709 , the number of output pages calculated in the step S 709 , and the output sheet information acquired in the step S 701 , whether or not center-fold processing is executable (step S 710 ). 
     If it is determined in the step S 710  that center-fold processing is not possible (NO to the step S 710 ), the process proceeds to the step S 714 . 
     On the other hand, if it is determined in the step S 710  that center-fold processing is executable (YES to the step S 710 ), the CPU  101  determines, based on the information acquired in the step S 706 , whether or not saddle-stitch processing is set (step S 711 ). Saddle-stitch processing is performed according to the finishing setting described in detail with reference to  FIG. 10B . 
     If it is determined in the step S 711  that saddle-stitch processing is not set (NO to the step S 711 ), the CPU  101  proceeds to the step S 713 . 
     On the other hand, if it is determined in the step S 711  that saddle-stitch processing is set (YES to the step S 711 ), the CPU  101  proceeds to a step S 712 , wherein the CPU  101  determines, based on the capability information of the finisher  109  acquired in the step S 709 , the number of output pages calculated in the step S 709 , and the output sheet information acquired in the step S 701 , whether or not saddle-stitch processing is executable (step S 712 ). 
     If it is determined in the step S 712  that saddle-stitch processing is not possible (NO to the step S 712 ), the CPU  101  proceeds to the step S 714 . On the other hand, if it is determined in the step S 712  that saddle-stitch processing is executable (YES to the step S 712 ), the CPU  101  proceeds to the step S 713 . 
       FIG. 15  is a flowchart of the printing process executed by the CPU  101  appearing in  FIG. 8 . 
     In the printing process shown in  FIG. 15 , the CPU  101  reads out the compressed original image stored in the HDD  104  (step S 801 ), and loads the read original image into the RAM  102 . 
     When the original image has been loaded into the RAM  102 , the CPU  101  instructs the image expansion section  115  to perform image processing for expanding the compressed original image loaded in the RAM  102  (step S 802 ). Then, upon receipt of a processing completion notification from the image-editing image processing section  114 , the CPU  101  proceeds to a step S 803 . Description of the processing performed by the image-editing image processing section  114  is omitted. 
     In the step S 803 , the CPU  101  instructs the printer engine  120  to print the original image subjected to image processing in the step S 802 . 
     Then, the CPU  101  determines whether or not all of the original images have been printed (step S 804 ). If it is determined in the step S 804  that all of the original images have not been printed (NO to the step S 804 ), the process returns to the step S 801 . 
     On the other hand, if it is determined in the step S 804  that all of the original images have been printed (YES to the step S 804 ), the CPU  101  deletes all of the original images which have been printed in the step S 803  from the RAM  102  and the HDD  104  (step S 805 ). 
     Then, when all of the original images have been deleted, the CPU  101  displays a print completion screen on the console section  121  (step S 806 ), followed by terminating the present process. When the printing process is terminated, the CPU  101  proceeds to a finishing process in  FIG. 16 . 
       FIG. 16  is a flowchart of the finishing process executed by the CPU  101  appearing in  FIG. 8 . 
     In the finishing process shown in  FIG. 16 , the CPU  101  acquires the finishing setting information (step S 901 ), and acquires the capability value of the finisher  109  (step S 902 ). 
     Next, the CPU  101  executes a fold setting process (step S 903 ). The fold setting process will be described in detail hereinafter with reference to the  FIG. 17 . 
     When the fold setting process is terminated, the CPU  101  executes a binding setting process (step S 904 ). In this process, a binding type and a binding position are compared with the capability information of the finisher  109  to check whether or not binding processing can be performed, and if binding processing can be performed, binding processing is added to the finishing setting. 
     When the binding setting process is terminated, the CPU  101  executes a trimming setting process (step  905 ). In this process, a trimming type, and trimming width and height are compared with the capability information of the finisher  109  to check whether or not trimming processing can be performed, and if the trimming processing can be performed, the trimming processing is added to the finishing setting. 
     Then, the CPU  101  executes processing for setting other finishing settings (step S 906 ). The other finishing settings include the setting of punching and the setting of shift discharge. In this process, a type and a set value in each of the other finishing settings are compared with the capability information of the finisher  109  to check whether or not each type of finishing processing can be performed, and if any type of finishing processing can be performed, the type of finishing processing is added to the finishing setting. 
     Next, the CPU  101  determines whether or not the processing operations to be executed according to the finishing settings set in the steps S 903  to S 906  include any combination of finishing processing operations that cannot be simultaneously performed (step S 907 ). 
     The step S 907  is executed to determine whether or not any types of finishing processing are set which can be each singly and separately performed but cannot be simultaneously performed. 
     If it is determined in the step S 907  that no combination of finishing processing operations that cannot be simultaneously executed are included (NO to the step S 907 ), the CPU  101  proceeds to a step S 909 , wherein the CPU  101  determines that all types of finishing processing set in the steps S 903  to S 906  are to be executed, and notifies the finisher  109  of the determination result via the accessory interface  108  (step S 909 ), followed by terminating the present process. Thereafter, when the job is completed, the standby screen is displayed. 
     On the other hand, if it is determined in the step S 907  that any combination of finishing processing operations that cannot be simultaneously executed are included (YES to the step S 907 ), the CPU  101  proceeds to a step S 908 , wherein the CPU  101  disables all types of finishing processing set in the steps S 903  to S 906  (step S 908 ), and deletes the temporarily stored settings of finishing processing, followed by terminating the present process. 
       FIG. 17  is a flowchart of the fold setting process executed by the CPU  101  appearing in  FIG. 8 . 
     In the fold setting process shown in  FIG. 17 , the CPU  101  acquires folding type information from the finishing setting information acquired in the step S 901  (step S 911 ). The folding type information also includes not only information on a folding type but also information on a folding position, a folding direction, and the number of sheets to be folded. 
     Next, the CPU  101  determines whether or not fold processing is set based on the information acquired in the step S 911  (step S 912 ). 
     If it is determined in the step S 912  that fold processing is not set (NO to the step S 912 ), the CPU  101  disables all types of fold processing (step S 918 ), followed by terminating the present process. Note that when the present process is terminated after execution of the step S 918 , the setting of the fold processing which has been temporarily stored is deleted in the step S 918 , and then the present process is terminated. 
     On the other hand, if it is determined in the step S 912  that fold processing is set (YES to the step S 912 ), the CPU  101  proceeds to a step S 913 , wherein the CPU  101  determines, based on the folding type information acquired in the step S 911  and the capability information of the finisher  109  acquired in the step S 902 , whether or not the set fold processing can be performed (step S 913 ). 
     If it is determined in the step S 913  that the set fold processing cannot be performed (NO to the step S 913 ), the CPU  101  proceeds to the step S 918 . 
     On the other hand, if it is determined in the step S 913  that the set fold processing can be performed (YES to the step S 913 ), the CPU  101  determines whether or not center-fold processing is set as the folding type acquired in the step S 911  (step S 914 ). 
     If it is determined in the step S 914  that center-fold processing is not set as the folding type (NO to the step S 914 ), the CPU  101  sets the folding type acquired in the step S 911  as finishing processing (step S 915 ), followed by terminating the present process. 
     On the other hand, if it is determined in the step S 914  that center-fold processing is set as the folding type (YES to the step S 914 ), the CPU  101  determines whether or not the folding type acquired in the step S 911  includes the setting of the folding position adjustment (step S 916 ). The folding position adjustment has been described in detail with reference to  FIG. 10F . 
     If it is determined in the step S 916  that the folding type does not include the setting of the folding position adjustment (NO to the step S 916 ), the CPU  101  proceeds to a step S 919 . 
     On the other hand, if it is determined in the step S 916  that the folding type includes the setting of the folding position adjustment (YES to the step S 916 ), the CPU  101  sets the folding position adjustment the setting of which is included in the folding type acquired in the step S 911  as finishing processing (step S 917 ). 
     Next, the CPU  101  determines whether or not the folding type acquired in the step S 911  includes the setting of the bookbinding lap adjustment (step S 919 ). The bookbinding lap adjustment has been described in detail with reference to  FIG. 10E . 
     If it is determined in the step S 919  that the folding type does not include the setting of the bookbinding lap adjustment (NO to the step S 919 ), the CPU  101  sets center-fold processing as finishing processing (step S 923 ), followed by terminating the present process. 
     On the other hand, if it is determined in the step S 919  that the folding type includes the setting of the bookbinding lap adjustment (YES to the step S 919 ), the CPU  101  acquires the binding setting from the finishing setting information acquired in the step S 901  (step S 920 ). 
     Next, the CPU  101  determines, based on the binding setting acquired in the step S 920 , whether or not saddle-stitch processing is set (step S 921 ). 
     If it is determined in the step S 921  that saddle-stitch processing is set (YES to the step S 921 ), the CPU  101  proceeds to the step S 923 . 
     On the other hand, if it is determined in the step S 921  that saddle-stitch processing is not set (NO to the step S 921 ), the CPU  101  proceeds to a step S 922 . Then, the CPU  101  sets the bookbinding lap adjustment included in the folding type information acquired in the step S 911  as finishing processing (step S 922 ), and proceeds to the step S 923 . 
       FIG. 18  is a view of an example of an output product (hereinafter referred to as the “fold section”)  1000  obtained in a case where the sheet processing apparatus  90  according to the present embodiment sets a bookbinding lap and performs processing operations up to center-fold processing. 
     In  FIG. 18 , in general, a side of the fold section  1000 , which is opened, is referred to as a fore edge  1001 , and a side of the same, which is closed, is referred to as a back  1002 . In the present embodiment, a difference in length is generated in the fore edge  1001  by setting the bookbinding lap. 
     The difference in length is referred to as a lap  1003 . Without the lap  1003 , assuming that saddle-stitch processing is to be performed by a post-processing apparatus which is a different system from the sheet processing apparatus  90 , it is impossible for the system to accurately feed the fold section  1000  and place the same on a gathering chain  1101  (see  FIG. 19A ) in an opened state. 
     The fold section  1000  is saddle-stitched, singly or together with a plurality of other fold sections in a stacked state, and then is trimmed to thereby form a finished saddle-stitched book. 
       FIG. 19A  is a schematic diagram showing post-processing steps executed by a post-processing apparatus  1200 . 
     With reference to  FIGS. 19A, 19B, and 20 , detailed description will be given of the steps in which fold sections created according to the present embodiment are processed by the post-processing apparatus  1200  which executes saddle-stitch bookbinding processing to create a saddle-stitched book. 
     In  FIG. 19A , S 1  to S 4  denote the fold sections  1000 , respectively, and the names of S 1  to S 4  are used for the sake of explanation, in order of superposing the fold sections  1000 . Further,  FIG. 19A  shows the conveyer (gathering chain)  1101  for conveying fold sections, a feeding lug  1102 , staple wires  1103 , head and foot knives  1104 , and a fore edge knife  1105 . 
     A step A is a collation step for superposing the fold sections  1000  created by the sheet processing apparatus  90  such that they can be formed into one book. 
     In the collation step A, the plurality of fold sections S 1  to S 4  which finally form one saddle-stitched book are fed onto the gathering chain  1101  one by one in a state in which the fore edge  1001  is opened. The fed fold sections are aligned by the feeding lug  1102  and collated. 
     The next step B is a saddle-stitching step for saddle-stitching the fold sections in the middle, which have been superposed in the step A, to thereby make a saddle-stitched book. 
     In the saddle-stitching step B, a collection of the fold sections aligned and superposed in the step A is stitched with the staple wires  1103 . 
     The next step C is a trimming step for shaping the book by trimming the head and foot and the fore edge of the saddle-stitched book created in the step B. 
     In the trimming step C, the collection of fold sections stitched in the preceding step B has its head and foot trimmed by the head and foot knives  1104 , and has its fore edge trimmed by the fore edge knife  1105 . 
     Thus, the fold sections  1000  created according to the present embodiment are formed into saddle-stitched books which are by the above-described saddle-stitch processing steps, and the books thus finished are accumulated. 
     The above-described steps executed by the post-processing apparatus  1200  form the fold sections  1000  into finished saddle-stitched books subjected to saddle-stitch processing and trimming processing. Hereafter, the steps will be more specifically described with reference to figures. Note that the post-processing apparatus  1200  is described only by way of example, and the present embodiment is not limited to the post-processing apparatus having a mechanism shown in this example, but can be applied to a post-processing apparatus which is capable of creating the fold sections  1000  effective to all post-processing apparatuses which handle the fold section  1000  having a lap. 
       FIG. 19B  is an overhead view of the post-processing apparatus  1200  shown in  FIG. 19A . 
     In  FIG. 19B , the post-processing apparatus  1200  includes a gathering chain controller  1201 , fold section-supplying units  1202  to  1204 , a cover supplying unit  1205 , and a central control unit  1206 . The post-processing apparatus  1200  further includes a saddle-stitching unit  1207 , a trimming unit  1208 , a trimming conveyer table  1209 , and an automatic accumulation unit  1210 . 
     The gathering chain controller  1201  and the fold section-supplying units  1202  to  1204  are used in the collation step A described with reference to  FIG. 19A . The saddle-stitching unit  1207  is used in the saddle-stitching step B described with reference to  FIG. 19A . The trimming unit  1208  and the trimming conveyer table  1209  are used in the trimming step C described with reference to  FIG. 19A . Hereafter, the respective units will be described in detail. 
     The gathering chain controller  1201  controls turning of the gathering chain  1101 . A pathway to the central control unit  1206  is connected by the same gathering chain  1101 , and the fold section-supplying units  1202  to  1204  and the cover supplying unit  1205  are arranged on the pathway. 
     The fold section-supplying units  1202  to  1204  feed the fold sections indicated by S 1  to S 3  in  FIG. 19A  onto the gathering chain  1101 , respectively. The operations of the fold section-supplying units  1202  to  1204  are controlled by the central control unit  1206 , and each fold section is fed in proper timing in synchronism with fold sections, if any, being conveyed on the gathering chain  1101 , and is superposed onto the conveyed fold sections. 
     The cover supplying unit  1205  supplies the fold section indicated by S 4  in  FIG. 19A  on the gathering chain  1101 . This fold section forms a cover when a saddle-stitched book is finished, and is collated at the end of the collation step. 
     The central control unit  1206  controls the overall operation of the post-processing apparatus  1200 . The central control unit  1206  includes a user interface, such as a touch screen operation panel, and the operator can perform centralized control of the entire saddle-stitching unit by operating the user interface. 
     The operator inputs dimensions of the fold section before trimming, and the head and foot, and fore edge of the trimmed fold section, a thickness of a finished saddle-stitched book, and so on. In accordance with the input, the settings for all of the steps using the fold section-supplying units  1202  to  1204 , the cover supplying unit  1205 , the saddle-stitching unit  1207 , the trimming unit  1208 , the trimming conveyer table  1209 , and the automatic accumulation unit  1210  are automatically configured. 
     Further, the timing between the operations performed by the fold section-supplying units  1202  to  1204  and the gathering chain  1101 , and the timing between the operations performed by the gathering chain  1101  and the saddle-stitching unit  1207  are automatically synchronized. The length of staple wires delivered by the saddle-stitching unit  1207  is also automatically adjusted in accordance with the thickness of the fold sections. 
     The saddle-stitching unit  1207  executes the saddle-stitching step B for stitching a collection of collated fold sections with the staple wires  1103 . The saddle-stitching unit  1207  receives the settings of the thickness of fold sections to be stitched, stitching points, stitching pressure, and so on from the central control unit  1206 . Further, usually, the saddle-stitching unit  1207  can be used as a single unit, and these settings can be input from the saddle-stitching unit  1207  itself. 
     The trimming unit  1208  executes the trimming step C for trimming the fore edge of a saddle-stitched book, and at the same time trimming the head and foot of the same. Trimmed waste generated during the trimming operation is collected in a collection container, not shown. The trimming unit  1208  receives the settings of the thickness of the fold sections to be trimmed, the width of the fore edge and the head and foot of a finished book, and so on, from the central control unit  1206 . Usually, these settings can also be input from the trimming unit  1208  itself, similarly to the saddle-stitching unit  1207 . 
     The trimming conveyer table  1209  performs conveyance of the fold sections before and after trimming. The trimming conveyer table  1209  performs processing for stopping conveyance of the fold sections at the moment of trimming so as to prevent the fold sections from being damaged during trimming, and for conveying the trimmed fold sections to the automatic accumulation unit  1210 . The automatic accumulation unit  1210  accumulates the finished saddle-stitched books by changing the orientation of saddle-stitched books, alternately, for each specified number of copies. 
       FIG. 20  is a cross-sectional view of each of the fold section-supplying units  1202  to  1204  appearing in  FIG. 19B . 
     In  FIG. 20 , the fold section-supplying units  1202  to  1204  disposed above the gathering chain are denoted by A 1 , A 2 , . . . , starting with the one closest to the gathering chain control unit  1201 . 
     Further, the fold section-supplying unit described with reference to  FIG. 20  is generally denoted by An, an associated fold section is generally denoted by Sn, the fore edge  1001  and the back of the fold section Sn are denoted by Sa and Sb, respectively. A cross section of the gathering chain  1101  is denoted by G. 
     Further,  FIG. 20  illustrates a fold section accumulation section  1301 , a sucker  1302 , a suction cup  1303 , an upper cylinder  1304 , grippers  1305   a ,  1305   b  of the upper cylinder  1304 , and upper cylinder guides  1306   a ,  1306   b .  FIG. 20  further illustrates a stopper  1307 , a counter-rotating roller  1308 , a lap cylinder  1309 , a gripper  1310  of the lap cylinder  1309 , an opening cylinder  1311 , a gripper  1312  of the opening cylinder  1311 , and a guide  1313 . 
     In  FIG. 20 , the fold section-supplying unit  1202  has fold sections stacked on the fold section accumulation section  1301  in a block. The fold sections are each accumulated such that an advanced fore edge side of the fore edge Sa (which includes, at this processing stage, advanced and withdrawn fore edge portions of sheets) is on a bottom side. The step for supplying the fold sections onto the gathering chain  1101  one by one from the collection of the stacked fold sections Sn will be described. 
     First, the sucker  1302  draws out each fold section Sn by hooking the back Sb using the suction cup  1303  included therein, and the gripper  1305   a  or  1305   b  of the upper cylinder  1304  draws out the fold sections Sn one by one. 
     The fold section Sn which has been drawn out is rotated in a manner setting the back Sb as a leading end, and is conveyed between the upper cylinder guides  1306   a  and  1306   b  and a peripheral surface of the upper cylinder  1304  until the fold section Sn is brought into abutment with the stopper  1307 , with the advanced fore edge portion side of the fore edge Sa positioned outside, and the withdrawn fore edge portion side of the fore edge Sa positioned inside. 
     As soon as the fold section Sn is brought into abutment with the stopper  1307 , the gripper  1305  is opened, and the counter-rotating roller  1308  removes the fold section Sn from the gripper  1305  to thereby case the fold section Sn to drop downward along the upper cylinder guide  1306 . 
     When the fold section Sn is dropped down, the gripper  1310  of the lap cylinder  1309  grips the withdrawn fore edge portion of the fore edge Sa of the fold section Sn, and the gripper  1312  of the opening cylinder  1311  grips the withdrawn fore edge portion of the fore edge Sa of the fold section Sn. 
     The lap cylinder  1309  and the opening cylinder  1311  are rotated in an opposite direction, and hence the fold section Sn is opened horizontally. Then, the opened fold section Sn drops in a direction indicated by an arrow. The fold section Sn which has dropped is put on the guide  1313  of the gathering chain  1101  which collects and conveys the fold sections S (S 1  to Sn−1) dropped from the fold section-supplying units A (A 1  to An−1). 
     Then, the fold sections S placed on the guide  1313  of the gathering chain  1101  are held by the feeding lug  1102  which is on a side toward the gathering chain controller  1201 , and are conveyed forward in a state placed on the guide  1313  of the gathering chain  1101 . 
     The fold sections S are thus sequentially dropped and are conveyed such that a following one is superposed on the preceding one, and are collated as described above. 
     In the above-described fold section-supplying units  1202  to  1204 , the gripper  1310  of the lap cylinder  1309  and the gripper  1312  of the opening cylinder  1311  appear when gripping the withdraw fore edge portion and the advanced fore edge portion of the fore edge Sa, respectively. 
     That is, if the fore edge Sa has no lap, or is smaller than required by the fold section-supplying units  1202  to  1204 , each gripper cannot properly grip the edge. 
     As described above, in the saddle-stitched bookbinding printing, in the case where the processing operations up to center-fold processing are performed by the sheet processing apparatus  90 , and saddle-stitch processing is performed using another system, a lap is required which is different depending on a system which performs saddle-stitch bookbinding processing. 
     In the present embodiment, the operator can specify the lap to be created in center-fold processing. 
     Therefore, the sheet processing apparatus  90  can produce center-folded print products adapted to systems which perform every type of saddle-stitch bookbinding processing, and enhance cooperation with these systems, to thereby make it possible to improve productivity in creating saddle-stitched books. 
     Further, it is possible to prevent a center-folded print product from being created which is unsuitable for a center-folding system, whereby it is possible to reduce wasted print products. 
     Although in the present embodiment, the description has been given of bookbinding printing processing using the copy function, by way of example, the present embodiment can also be applied to a case using a print function. 
     Next, a second embodiment of the present invention will be described. The sheet processing apparatus  90  according to the second embodiment has the same configuration and software module configuration as the sheet processing apparatus  90  according to the first embodiment. 
     In the first embodiment, the description has been given of the operation of the CPU  101  for creating a lap by shifting a folding position, which is set to the finisher  109  via the accessory interface  108 , in center-fold processing executed when the operator has set the lap in the bookbinding lap adjustment shown in  FIG. 10E . 
     In the first embodiment, the operator is required to perform adjustment using e.g. the print position adjustment described with reference to  FIG. 10D  such that the position of an image is correctly set with respect to a folding position according to a shift amount of the folding position. 
     In the second embodiment, the print position adjustment which is required when the folding position is shifted by the bookbinding lap adjustment is automatically performed by the CPU  101  and the printer image processing section  118  such that an image is properly positioned. 
     In the second embodiment, similarly to the first embodiment, upon receipt of selection of the copy function, the standby screen is displayed on the console section  121 , and the waiting-time process shown in  FIG. 11  is executed. 
     Further, similarly to the first embodiment, the scanning process in  FIG. 12  is executed when the CPU  101  determines in the step S 419  in  FIG. 11  that the copy start button has been operated on the console section  121 . 
       FIGS. 21A and 21B  are diagrams useful in explaining automatic print adjustment performed in accordance with the bookbinding lap adjustment. 
       FIGS. 21A and 21B  show imposition positions arranged when images  1404  and  1405  of two pages are imposed on a surface of a sheet  1401 . 
       FIG. 21A  shows an example of an output product obtained when the bookbinding lap adjustment has not been performed. 
     In a case where the print position adjustment value is not specified by the operator according to the print position adjustment described with reference to  FIG. 10D , the images  1404  and  1405  of two pages are imposed with a centerline  1402  of the sheet  1401  positioned in the center, as indicated by an imposed image example  1406 . 
     Since the bookbinding lap adjustment is not performed, the folding position at which center-fold processing is to be performed is along the centerline  1402  of the sheet  1401 . 
     Usually, the images on two pages are reduced in size with respect to a sheet, or the images are provided with an area (margin) which is not important in printing. Therefore, when two pages are printed along the centerline  1402 , part which is not printed is formed on a fore edge side, or the area which is unimportant is printed on the fore edge side. 
     This part which is not printed or the unimportant area corresponds to a trim width  1408  on the fore edge side, and the area of the trim width  1408  is cut off by edge trimming in the trimming step C, whereby a final product  1409  has no margin. 
       FIG. 21B  shows an example of an output product obtained when the bookbinding lap adjustment has been performed according to the second embodiment. 
     In the case where the bookbinding lap adjustment has been performed, a folding position  1411  at which center-fold processing is to be performed is shifted from the centerline  1402  of the sheet  1401  by the bookbinding lap adjustment value. 
     Therefore, if the print position adjustment is not performed, the images  1404  and  1405  of two pages imposed along the centerline  1402  are not printed at correct locations with respect to the folding position  1411 , and further, important part of the images is sometimes cut off in the trimming step. 
     To solve this problem, in the second embodiment, the print position adjustment is automatically performed when performing the bookbinding lap adjustment such that images are imposed along the folding position as illustrated in an imposed image  1412 . 
     In the case of a print product  1413  created according to the second embodiment, an advanced fore edge portion formed according to the lap includes a larger part which is not printed or unimportant. The larger part which is not printed or unimportant corresponds to a trim width  1414  on the fore edge side. 
     The part of the trim width  1414  is cut off by edge trimming in the trimming step C, whereby a final product  1415  has no margin. 
       FIG. 22  is a flowchart of a print instruction process executed by the CPU  101  appearing in  FIG. 8 . 
     The process in  FIG. 22  is the process for instructing the printer engine  120  to perform printing, which is executed in the step S 803  in the printing process in  FIG. 15 . 
     The CPU  101  acquires print setting information (step S 1501 ), and acquires finishing setting information (step S 1502 ). 
     Next, the CPU  101  determines, based on the finishing setting information acquired in the step S 1502 , whether or not center-fold processing is set (step S 1503 ). If it is determined in the step S 1503  that center-fold processing is not set (NO to the step S 1503 ), the CPU  101  proceeds to a step S 1507 . 
     On the other hand, if it is determined in the step S 1503  that center-fold processing is set (YES to the step S 1503 ), the CPU  101  determines, based on the print setting information acquired in the step S 1501 , whether or not the bookbinding lap adjustment is set (step S 1504 ). 
     If it is determined in the step S 1504  that the bookbinding lap adjustment is not set (NO to the step S 1504 ), the CPU  101  proceeds to the step S 1507 . 
     On the other hand, if it is determined in the step S 1504  that the bookbinding lap adjustment is set (YES to the step S 1504 ), the CPU  101  proceeds to a step S 1505 . The CPU  101  reads out the bookbinding lap adjustment amount from the print setting information acquired in the step S 1501 , and changes the position of an imposition reference line with reference to which the position of each image is set for imposition (step S 1505 ). The change of the position of the imposition reference line will be described hereinafter with reference to  FIGS. 23A to 23C . Further, note that in the second embodiment, an initial position of the reference line is set to the centerline  1402  of the sheet. 
     Next, the CPU  101  determines, based on the print setting information acquired in the step S 1501 , whether or not the bookbinding imposition is set (step S 1506 ). The bookbinding imposition setting has been described in detail with reference to  FIG. 10B . 
     If it is determined in the step S 1506  that the bookbinding imposition is not set (NO to the step S 1506 ), the CPU  101  proceeds to a step S 1509 . On the other hand, if it is determined in the step S 1506  that the bookbinding imposition is set (YES to the step S 1506 ), the CPU  101  determines, based on the print setting information acquired in the step S 1501 , whether or not the creep correction is set (step S 1507 ). 
     If it is determined in the step S 1507  that the creep correction is not set (NO to the step S 1507 ), the CPU  101  proceeds to the step S 1509 . On the other hand, if it is determined in the step S 1507  that the creep correction is set (YES to the step S 1507 ), the CPU  101  reads out a creep correction amount from the print setting information acquired in the step S 1501 , and sets the creep correction amount with respect to the reference line (step S 1508 ). This setting will also be described hereinafter with reference to  FIGS. 23A to 23C . 
     Next, the CPU  101  determines, based on the print setting information acquired in the step S 1501 , whether or not the print position adjustment is set (step S 1509 ). If it is determined in the step S 1509  that the print position adjustment is not set (NO to the step S 1509 ), the CPU  101  proceeds to a step S 1511 . 
     On the other hand, if it is determined in the step S 1509  that print position adjustment is set (YES to the step S 1509 ), the CPU  101  proceeds to a step S 1510 . The CPU  101  reads out a print position adjustment value from the print setting information read in the step S 1501 , and sets the print position adjustment amount shifted from the reference line (step S 1510 ). This setting will also be described hereinafter with reference to  FIGS. 23A to 23C . 
     Next, the CPU  101  notifies the printer image processing section  118  of the print setting information acquired in the step S 1501  and imposition information which is a calculation result of the sum of the amounts of adjustment of the image position from the initial value of the reference line (i.e. the centerline  1402 ), which have been calculated in the steps S 1503  to S 1510 . That is, the CPU  101  notifies the printer image processing section  118  of the imposition information and the print setting information (step S 1511 ). 
     Then, the CPU  101  instructs the printer engine  120  to perform printing via the printer image processing section  118  (step S 1512 ), followed by terminating the present process. Printing processing and finishing processing after providing the print instruction are executed similarly to the first embodiment. 
       FIGS. 23A to 23C  are diagrams useful in explaining a change of the imposition reference position, the creep correction amount, and the print position adjustment amount, which are calculated by the CPU  101  in the steps S 1505 , S 1508 , and S 1510  in  FIG. 22 , respectively. 
     In  FIGS. 23A to 23C , M denotes the centerline  1402 , and K denotes the reference line of the image position. It is assumed that the sheet and the imposed images are folded in a manner facing outward in folding processing. 
       FIG. 23A  is the diagram useful in explaining the change of the imposition reference position. A displacement  1601  between the reference line K and the centerline M, calculated in the step S 1505 , is equal to an amount of the bookbinding lap adjustment set in  FIG. 10E . 
     Assuming that the set bookbinding lap is X, the positive direction in  FIGS. 23A to 23C  is a right direction, and hence the reference line of the image position is shifted by (X, 0). Therefore, respective displacements between the images  1404  and  1405 , and the image position before changing the reference position are both expressed by (X, 0). When the creep correction is not performed, in a case where the reference line is not on the centerline, the printer engine  120  forms the images in such a manner that the image forming position is shifted from the position where the images are formed when the folding line is on the centerline, by the bookbinding lap X. 
       FIG. 23B  is a diagram useful in explaining a displacement  1602  of the image imposition position from the centerline, calculated when the creep correction amount is further set after the imposition reference position has been changed. 
     The creep correction is a function for performing printing such that the width of images of two pages to be printed on a side of a sheet is made narrower than the width of those to be printed on a side of an outer sheet because an inner sheet protrudes outside by an amount corresponding to the thickness of sheets when the center-folding processing is performed as described above. 
     Therefore, in a case where the creep correction amount set to the sheet is calculated as “a” according to the creep correction amount set in  FIG. 10A , a displacement in image position between the left image  1404  and the image before the change of the reference position and the creep correction is expressed by (X+a, 0). Further, a displacement in image position between the right image  1405  and the image before the change of the reference position and the creep correction is expressed by (X−a, 0). 
     As described above, in the case where the reference line is not on the centerline and an image is formed after performing the creep correction, the printer engine  120  forms the image at a position shifted from a position where the image is formed when the folding line is on the centerline, by the bookbinding lap, and further shifted by the creep correction amount. In the case of  FIG. 23B , the positions set after the creep correction are expressed by (X+a, 0) and (X−a, 0). 
       FIG. 23C  is the diagram useful in explaining a displacement  1603  of the image imposition position from the centerline in the horizontal direction and a displacement  1604  of the same in the vertical direction, calculated when the imposition reference position has been changed and further the print position is set. 
     The print position adjustment is a function for vertically and horizontally adjusting the print position, and is set by the operator using the screen shown in  FIG. 10D . The print position adjustment for shifting the position upward is performed by setting a positive value for a vertical direction and the print position adjustment for shifting the position to the right is performed by setting a positive value for a horizontal direction. The set value for the horizontal direction is represented by “x”, and the set value for the vertical direction is represented by “y”. 
     At this time, the displacements in position between the images  1404  and  1405 , and the images before the change of the reference position and the print position adjustment are both expressed by (X+x, y). 
     Note that the folding position fine adjustment described with reference to  FIG. 10F  is for finely adjusting a folding position in a case where the folding position on a sheet is displaced, and hence the folding position fine adjustment is not taken into consideration in determining the print position of an image. 
     As described above, when the bookbinding lap adjustment is set, the imposition reference line is changed based on the set bookbinding lap adjustment value, which enables the sheet processing apparatus  90  to automatically shift the image imposition position to a correct position with respect to the folding position. 
     This makes it possible to reduce time and effort of the operator for manually setting a print position by an amount of displacement of the folding position. 
     Further, although in the present embodiment, the description has been given of an example in which assuming that the set bookbinding lap is represented by X, the reference line K of the image position is shifted by (X, 0), this is not limitative, but the reference line K of the image position may be shifted by (X/2, 0). By shifting the reference line K of the image position, it is possible to adjust the reference line K of the image position to the center of an area exclusive of the bookbinding lap. With this, when the sheet is folded in two, as shown in  FIG. 18 , the fold line of the folded sheet and the center of images formed on the sheet are aligned with each other, which improves the appearance of images after the part of the trim width  1414  of the sheet is trimmed off. 
     Although the description has been mainly given of the case where imposition is performed by the sheet processing apparatus  90 , the second embodiment can also be applied to a case where images subjected to imposition are printed. Further, the second embodiment can be practiced in combination with the first embodiment. Further, the second embodiment can be executed not only for a copy job, but also similarly for a print job. 
     Next, a third embodiment of the present invention will be described. The sheet processing apparatus  90  according to the third embodiment has the same configuration and software module configuration as the sheet processing apparatus  90  according to the first and second embodiments. 
     In the first and second embodiments, in the system which performs saddle-stitch processing on the fold sections  1000  created by the sheet processing apparatus  90 , the operator is required to set a necessary bookbinding lap from the bookbinding lap adjustment screen  350  whenever center-fold processing is performed. 
     In the third embodiment, the sheet processing apparatus  90  sets a bookbinding lap required by each system which performs saddle-stitch processing (hereinafter referred to as the saddle-stitch processing apparatus). 
     More specifically, when the saddle-stitch processing apparatus is connected to the sheet processing apparatus  90 , the CPU  101  recognizes the type of the connected saddle-stitch processing apparatus via the accessory interface  108 . 
     On the other hand, when no saddle-stitch processing apparatus is connected to the sheet processing apparatus  90 , the CPU  101  recognizes type information for identifying a saddle-stitch processing apparatus from setting information of saddle-stitch processing apparatuses, which has been registered from a registration screen for registering saddle-stitch processing apparatuses. 
     The type of a saddle-stitch processing apparatus is thus recognized, and the CPU  101  automatically applies the bookbinding lap required by the saddle-stitch processing apparatus of the recognized type from a database connected through a network via the LAN  122  or a database included in the HDD  104  to thereby set the necessary lap. 
     In the third embodiment, the waiting-time process in  FIG. 11  is executed similarly to the first and second embodiments. The subsequent scanning process in  FIG. 12 , the output sheet-setting process in  FIG. 13 , the bookbinding determination process in  FIG. 14 , and the finishing process in  FIG. 16  are executed similarly to the first embodiment. 
       FIG. 24  is a diagram showing a saddle-stitch processing apparatus registration screen  1700  used for registering an apparatus which performs saddle-stitch processing. 
     As shown in  FIG. 24 , by registering a saddle-stitch processing apparatus in the sheet processing apparatus  90  after creating the fold sections  1000 , the sheet processing apparatus  90  can automatically set a necessary lap without inputting a lap necessary for the bookbinding lap adjustment by the operator. 
     In  FIG. 24 , a saddle-stitch processing apparatus selection button  1701  is used for selecting a saddle-stitch processing apparatus to be registered. A name, a model name, and a necessary lap of a saddle-stitch processing apparatus are displayed on saddle-stitch processing apparatus selection button  1701 . A saddle-stitch processing apparatus selected by the operator is highlighted. 
     A details button  1702  can be selected only in a state where a saddle-stitch processing apparatus selection button  1701  has been selected, and cannot be selected in a state where no saddle-stitch processing apparatus selection button  1701  has been selected. 
     When the operator operates the details button  1702  in the selectable state, a saddle-stitch processing apparatus detail screen, not shown, for displaying saddle-stitch processing apparatus information which is information on the saddle-stitch processing apparatus selected at that time is displayed. 
     The saddle-stitch processing apparatus detail screen displays saddle-stitch processing apparatus information items stored in the HDD  104  in association with respective saddle-stitch processing apparatuses, and the operator can change the registered saddle-stitch processing apparatus information by operating the console section  121  as required. 
     A cancel button  1703  is used for aborting the saddle-stitch processing apparatus registration. When the operator operates the cancel button  1703 , the temporarily stored registration of a saddle-stitch processing apparatus is abandoned, and the standby screen, not shown, is displayed. 
     A return button  1704  is used for terminating saddle-stitch processing apparatus registration. When the operator operates the return button  1704 , the standby screen is displayed without registering a saddle-stitch processing apparatus. 
     An OK button  1705  is used for completing the saddle-stitch processing apparatus registration. When the operator operates the OK button  1705 , a saddle-stitch processing apparatus is registered, and the standby screen is displayed. 
     The operator can operate the OK button  1705  only when one of saddle-stitch processing apparatuses is selected using the saddle-stitch processing apparatus selection button  1701 . When no saddle-stitch processing apparatus is selected, the OK button  1705  cannot be operated. 
       FIG. 25  is a flowchart of a fold setting process executed by the CPU  101  appearing in  FIG. 8 . 
     In  FIG. 25 , the CPU  101  acquires information of the folding type from the finishing setting information acquired in the step S 901  (step S 1801 ). 
     Next, the CPU  101  determines, based on the information acquired in the step S 1801 , whether or not the fold processing is set (step  1802 ). 
     If it is determined in the step S 1802  that the fold processing is not set (NO to the step S 1802 ), the CPU  101  disables any fold processing (step S 1810 ), followed by terminating the present process. Note that when the present process is terminated after execution of the step S 1810 , the setting of the fold processing which has been temporarily stored is deleted in the step S 1810 , and then the present process is terminated. 
     On the other hand, if it is determined in the step S 1802  that the fold processing is set (YES to the step S 1802 ), the CPU  101  proceeds to a step S 1803 , wherein the CPU  101  determines, based on the folding type acquired in the step S 1801  and the capability information of the finisher  109  acquired in the step S 902 , whether or not the set fold processing can be performed (step S 1803 ). 
     If it is determined in the step S 1803  that the set fold processing cannot be performed (NO to the step S 1803 ), the CPU  101  proceeds to the step S 1810 . 
     On the other hand, if it is determined in the step S 1803  that the set fold processing can be performed (YES to the step S 1803 ), the CPU  101  determines whether or not center-fold processing is set as the folding type acquired in the step S 1801  (step S 1804 ). 
     If it is determined in the step S 1804  that center-fold processing is not set (NO to the step S 1804 ), the CPU  101  sets the folding type acquired in the step S 1801  as finishing processing (step S 1805 ), followed by terminating the present process. 
     On the other hand, if it is determined in the step S 1804  that center-fold processing is set (YES to the step S 1804 ), the CPU  101  determines whether or not the folding position adjustment is set as the folding type acquired in the step S 1801  (step S 1806 ). The folding position adjustment has been described in detail with reference to  FIG. 10F . 
     If it is determined in the step S 1806  that the folding position adjustment is not set as the folding type (NO to the step S 1806 ), the CPU  101  proceeds to a step S 1808 . 
     On the other hand, if it is determined in the step S 1806  that the folding position adjustment is set as the folding type (YES to the step S 1806 ), the CPU  101  sets the folding position adjustment included in the folding type acquired in the step S 1801  as finishing processing (step S 1807 ). 
     Next, the CPU  101  determines whether or not the bookbinding lap adjustment is set as the folding type acquired in the step S 1801  (step S 1808 ). The bookbinding lap adjustment has been described in detail with reference to  FIG. 10E . 
     If it is determined in the step S 1808  that the bookbinding lap adjustment is not set as the folding type (NO to the step S 1808 ), the CPU  101  sets center-fold processing as finishing processing (step S 1818 ), followed by terminating the present process. 
     On the other hand, if it is determined in the step S 1808  that the bookbinding lap adjustment is set as the folding type (YES to the step S 1808 ), the CPU  101  acquires information of the finisher  109  via the accessory interface  108  (step S 1809 ). 
     Next, the CPU  101  determines, based on the finisher information acquired in the step S 1809 , whether or not a saddle-stitch processing apparatus is mounted as the finisher  109  (step S 1811 ). 
     If it is determined in the step S 1811  that a saddle-stitch processing apparatus is mounted (YES to the step S 1811 ), the CPU  101  proceeds to a step S 1813 . On the other hand, if it is determined in the step S 1811  that no saddle-stitch processing apparatus is not mounted (NO to the step S 1811 ), the CPU  101  determines whether or not a saddle-stitch processing apparatus has been registered according to the saddle-stitching device registration described with reference to  FIG. 17  (step S 1812 ). 
     If it is determined in the step S 1812  that saddle-stitch processing apparatus has not been registered (NO to the step S 1812 ), the CPU  101  proceeds to the step S 1818 . 
     On the other hand, if it is determined in the step S 1812  that a saddle-stitch processing apparatus has been registered (YES to the step S 1812 ), the process proceeds to the step S 1813 . The CPU  101  acquires the type of the saddle-stitch processing apparatus based on the saddle-stitch processing apparatus information acquired in the step S 1809  or the registered saddle-stitch processing apparatus information (step S 1813 ). 
     Next, the CPU  101  acquires the bookbinding lap required by the saddle-stitch processing apparatus corresponding to the type acquired in the step S 1813  from the database connected through the network via the LAN  122  or the database included in the HDD  104  (step S 1814 ). The step S 1814  corresponds to the operation of an acquisition unit configured to acquire a bookbinding lap required by a saddle-stitch processing apparatus which performs saddle-stitch processing on fold sections created by the finisher  109 . Further, the acquisition unit acquires a bookbinding lap from the HDD  104  (storage unit) which stores the bookbinding lap associated with each saddle-stitch processing apparatus in advance as described above. Alternatively, the acquisition unit acquires a bookbinding lap from an apparatus connected via the network using the type information for identifying a saddle-stitch processing apparatus. 
     Then, the CPU  101  acquires the binding setting from the finishing setting information acquired in the step S 901  (step S 1815 ). 
     Next, the CPU  101  determines, based on the binding setting acquired in the step S 1815 , whether or not saddle-stitch processing is set (step S 1816 ). 
     If it is determined in the step S 1816  that saddle-stitch processing is set (YES to the step S 1816 ), the CPU  101  proceeds to the step S 1818 . 
     On the other hand, if it is determined in the step S 1816  that saddle-stitch processing is not set (NO to the step S 1816 ), the CPU  101  sets the bookbinding lap acquired in the step S 1814  to finishing processing (step S 1817 ), and proceeds to the step S 1818 . 
     As described above, when a saddle-stitch processing apparatus is connected or has been registered, by acquiring a necessary amount of a lap from the type of saddle-stitch processing apparatus, it is possible to automatically set the bookbinding lap adjustment amount. 
     The third embodiment can be practiced in combination with the first and second embodiments. Further, the third embodiment can be executed not only for a copy job, but also similarly for a print job. 
     As described heretofore, according to the first to third embodiments described above, first, a bookbinding lap is set which is defined as a difference in distance from a fold line to opposite fore edge portions of each recording sheet of a fold section to be formed by forming the fold line on recording sheets having images formed thereon by the printer engine  120  (step S 412 ). Then, the fold section is created by the finisher  109  by forming the folding line on the recording sheets according to a reference line which is shifted by the set bookbinding lap from the centerline indicative of a folding position to be formed when no lap is provided. Therefore, the bookbinding lap of a fold section can be freely set, and hence it is possible to create fold sections suitable for an apparatus which performs saddle-stitch processing on the fold sections. 
     As described above, according to the present embodiment, in the case where after fold sections are created by the sheet processing apparatus  90 , the steps of saddle-stitch processing et seq. are executed using another system, it is possible to create a lap which is necessary for said another system to feed the fold sections. Further, images are properly printed by automatically adjusting the print position in accordance with the center-folding position, whereby it is possible to save the operator time and effort for adjusting the print position by performing test printing, and prevent unnecessary print products from being generated. 
     Aspects of the present invention can also be realized by a computer of a system or apparatus (or devices such as a CPU or MPU) that reads out and executes a program recorded on a memory device to perform the functions of the above-described embodiments, and by a method, the steps of which are performed by a computer of a system or apparatus by, for example, reading out and executing a program recorded on a memory device to perform the functions of the above-described embodiments. For this purpose, the program is provided to the computer for example via a network or from a recording medium of various types serving as the memory device (e.g., computer-readable medium). 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2012-144340, filed Jun. 27, 2012, which is hereby incorporated by reference herein in its entirety.