JP2002365969A - Imaging apparatus, book-binding mode control method, book-binding mode control program and recording medium with the program stored - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bend a stack of paper formed by many pieces of paper at high quality by carrying out an appropriate processing, by changing control according to whether or not a split up mode is set in the book binding mode. SOLUTION: In the book-binding mode, a split up mode carrying out post processing at a post processing part, by splitting up the multiple number of pieces of output paper forming a pamphlet into a multiple number of split paper stacks is set. In this case, when the split up mode is selected, a surface- assigning means for controlling positioning of images so that the image data on the front and back sides of each piece of outputted paper forming the split paper stacks are assigned to 2 pages with each split paper stack being in the order of the pages is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for printing on a front surface and a back surface of each output sheet based on image data allocated so that a plurality of output sheets are arranged in a page order when the sheets are folded back from the center. The present invention relates to an image forming apparatus that folds a sheet in half for bookbinding, a bookbinding mode control method, a bookbinding mode control program, and a storage medium on which the program is recorded.

[0002]

2. Description of the Related Art Conventionally, all originals to be copied are read, the obtained original image data is temporarily stored in an external storage device such as a hard disk, and the original image data is repeatedly printed from the external storage device during printout. 2. Description of the Related Art Digital copiers having an electronic sort function for reading and printing out based on the original image data are known.

When a pamphlet function is performed by using a digital copying machine having such an electronic sort function, the pamphlet created on the output paper is arranged in a page order so that the output is folded back at the center line. On the front and back of the paper, so that the original is divided into two pages each,
It controls the placement of the original image. After creating a left-opening right-bound book, the saddle switch device stitched along the center line of the stacked output paper and turned it back to realize the binding of a weekly magazine.

[0004]

However, when the number of pages of the output paper is large or when the thickness of the output paper is large, the paper bundle is folded and the discharged paper bundle is opened. Was sometimes In addition, when performing punching or the like on the output sheet bundle, if the number of pages is large, there is a restriction that punching cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems, and to control an image forming apparatus, a bookbinding mode control method, and a bookbinding mode which can perform appropriate processing by changing the control depending on whether or not a division mode is set in a bookbinding mode. An object of the present invention is to provide a mode control program and a computer-readable recording medium on which the program is recorded.

[0006]

In order to achieve the above object, an image forming apparatus according to the present invention comprises an image forming section for forming images on the front and back surfaces of a sheet, and a plurality of sheets output from the image forming section. It has a post-processing unit that folds output paper and folds it at the center to bind the book. In the bookbinding mode, two pages of image data are printed on the front and back of the output paper so that pamphlets created with multiple sheets of output paper are arranged in page order. In the image forming apparatus which controls the image arrangement so as to be divided, in the bookbinding mode, a plurality of output sheets constituting a pamphlet are divided into a plurality of divided sheet bundles, and post-processing is performed by the post-processing unit. Mode is set, and when the division mode is selected, the image data is divided into two pages on the front and back sides of each output sheet constituting the division sheet bundle so that the division sheet bundle is arranged in the page order. And having a surface with means for controlling the image arrangement as vignetting.

Further, the imposition means controls the image arrangement for each of the divided sheet bundles so that all the pages of the sheets constituting the pamphlet have continuous page numbers. .

Further, in the bookbinding mode control method for an image forming apparatus according to the present invention, an image forming section for forming an image on the front and back surfaces of a sheet, and a plurality of output sheets output from the image forming section are overlapped with a center. In the bookbinding mode, the brochure created with a plurality of output sheets is arranged in the page order so that the image data can be divided into two pages on both sides of the output sheet. In the image forming apparatus that controls the arrangement, when the number of output sheets is larger than the number that can be processed by the post-processing unit, the plurality of output sheets forming the pamphlet are divided into a plurality of divided sheet bundles, and each divided sheet bundle is The post-processing unit performs post-processing, and the image data is divided into two pages on the front and back sides of each output sheet constituting the divided sheet bundle so that the divided sheet bundle is in page order. It is characterized in.

Further, a bookbinding mode control program for an image forming apparatus according to the present invention includes the following steps:
When all the original images are stored in the image storage unit, the number of output sheets is obtained from the number of original images, and then it is determined whether the number of output sheets is larger than the number that can be processed by the post-processing unit. Calculates the number of divisions of a plurality of output sheets constituting a pamphlet into divided sheet bundles for each predetermined number of sheets, and in the case of a negative determination, sets the number of divisions n to 1 and proceeds to the next step to count the number of divisions The counter k is set to 1, and the k-th divided output sheet is controlled so as to be output to the post-processing section as needed. 2 each
Controls the layout of the original image on the page, forms an image until the number of sheets to be post-processed is reached, outputs the sheet to the post-processing unit, then folds the output sheet in half in the post-processing unit and discharges it. It is determined whether or not the divided sheet bundle is the final bundle of the division. In the case of a negative determination, the division number counter k is incremented by one and the processing of the next divided sheet bundle is performed. Judge whether the output of the number of copies has been completed,
If the determination is negative, the bookbinding procedure is repeated, and if the determination is affirmative, the processing in the bookbinding mode is terminated.

[0010] Further, the storage medium storing the bookbinding mode control program according to the present invention stores the above bookbinding mode control program.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 4 shows a configuration example of a general image forming apparatus to which the present invention is applied. FIG. 5 is a perspective view showing the appearance of the finisher and the saddle stitching device shown in FIG. The following description of an embodiment of the image forming apparatus according to the present invention also serves as a description of an embodiment of a bookbinding mode control method, a bookbinding mode control program, and a storage medium on which the program is recorded.

This image forming apparatus includes a copying apparatus main body 100 as an image forming section and a circulating automatic document feeder (AD).
F) 180, and a finisher 401 as a post-processing unit that overlaps a plurality of output sheets output from the copying apparatus main body 100, folds them at the center, and performs bookbinding.

The reading mode of the ADF 180 includes AD
There are a descending reading mode in which the document placed in the F180 is fed from below, and an ascending reading mode in which the document is fed from above.

The copying apparatus main body 100 will be described. Reference numeral 101 denotes a platen glass as a document placing table, and an ADF 18
0 is for placing the original fed.
Reference numeral 102 denotes a scanner, which includes a document illumination lamp 103 and a scanning mirror 104, and scans a document placed on the document table 101.

When the scanner 102 is reciprocally scanned in a predetermined direction by a motor (not shown), reflected light from the original is
Light guided to the lens 108 via the scanning mirrors 104 to 106 and transmitted through the lens 108 is transmitted to a reading element (CCD (Chain)).
rge coupled device)). CCD1
The image signal from 09 is subjected to predetermined image processing described later.

An exposure controller 120 has a laser and a polygon scanner, and emits a modulated laser beam 129. The emitted laser light is guided to the photosensitive drum 110 by a plurality of mirrors.

Reference numeral 126 denotes an image forming unit, which includes a primary charger 112 and a developing unit 121 around the photosensitive drum 110.
Transfer charger 118, cleaning device 116,
A pre-exposure lamp 114 is provided.

The photosensitive drum 110 is rotated by a motor (not shown) in a direction indicated by an arrow in FIG.
After being charged to a desired potential by the exposure control unit 120,
Is irradiated with the laser light 12 from the photoconductor drum 110 to form an electrostatic latent image on the photosensitive drum 110. The electrostatic latent image formed on the photosensitive drum 110 is developed by the developing device 121 and is visualized as a toner image.

Reference numeral 131 denotes an upper cassette, and 132 denotes a lower cassette for storing sheets.

The sheets in the upper cassette 131 are taken out one by one by a pickup roller 133 and passed through a path 160 by a sheet feeding roller 135 to a registration roller 137.
Sent to The sheets in the lower cassette 132 are taken out one by one by a pickup roller 134, passed through a path 160 by a feed roller 136, and registered by a registration roller 137.
Sent to

Reference numeral 118 denotes a transfer charger, which transfers a toner image on the photosensitive drum 110 to a sheet (transfer sheet) sent to a transfer belt 130 by a registration roller 137.

The residual toner on the photosensitive drum 110 after the transfer is cleaned by a cleaner device 116, and the residual charge is erased by a pre-exposure lamp 114.

Reference numeral 119 denotes an adsorption charger, which adsorbs the transfer paper sent from the registration roller 137 to the transfer belt 130.

Reference numeral 138 denotes a transfer belt roller for rotating the transfer belt 130.
In cooperation therewith, the transfer paper is adsorbed and charged on the transfer belt 130. The transfer paper after the transfer is separated from the transfer belt 130, and the toner image on the transfer paper is charged into the pre-fixing chargers 139, 1
The sheet is recharged by 40, then fixed by being pressed and heated by a fixing device 141, and discharged out of the main body 100 by a sheet discharging roller 142.

Reference numeral 150 denotes a deck for storing a large amount of transfer paper, for example, 4000 transfer papers.

Reference numeral 151 denotes a lifter 151 of the deck 150, which is designed to keep the transfer paper in contact with the paper feed roller 152.
It increases according to the amount of transfer paper. 153 is multi manual feed 1
53, which can accommodate, for example, 100 transfer papers.

Reference numeral 154 denotes a paper discharge flapper for switching the path between the double-side recording side or the multiple recording side and the paper discharge side. The transfer paper fed from the paper discharge roller 142 is switched by the paper discharge flapper 154 to a double-sided recording side or a multiple recording side.

Reference numeral 158 denotes a lower transport path, which is a discharge roller 1
The transfer paper sent out from 42 is passed through a reversing path 155,
This is for turning the transfer paper upside down and guiding it to the re-feed tray 156.

Reference numeral 157 denotes a multiplex flapper for switching the path between double-sided recording and multiplex recording. The flapper is tilted to the left so that the transfer paper is guided directly to the lower transport path 158 without passing through the reversing path 155. It is. Reference numeral 159 denotes a paper feed roller for feeding the transfer paper to the photosensitive drum 126 through the path 160.

Reference numeral 161 denotes a discharge roller, which is disposed near the discharge flapper 154, and discharges the transfer sheet switched to the discharge side by the discharge flapper 154 to the outside of the apparatus.

At the time of double-sided recording (double-sided copying) or multiple recording (multiplexed copying), the discharge flapper 154 is raised upward, and the copied paper is turned upside down via the transport paths 155 and 158 to re-feed the tray. 156.

At this time, at the time of double-sided printing, the multiplex flapper 157 is tilted to the right, and at the time of multiplex printing, the transfer paper stored in the re-feed tray 156 is moved one by one from the bottom along the path 160 by the feed roller 159. Through the registration roller 13 of the main body.

When the transfer paper is inverted and discharged from the main body, the discharge flapper 154 is raised upward, and the multiple flapper 1
57 to the right and transport the copied transfer paper to transport path 15
5 and the rear end of the transfer paper is
Is transferred to the second feed roller side by the reversing roller 163, and the transfer paper is turned over by the discharge roller 161 and discharged out of the apparatus.

The transfer paper is discharged to a finisher 401 which is a post-processing section, as shown in FIG. 402, 4
Reference numerals 03 and 404 denote staple trays, in which transfer papers are stored in the finisher 401 for each staple unit, and the stored transfer papers are stapled and discharged to a predetermined tray.

In the case of a pamphlet mode described later,
The transfer paper is stored for each stitch in the finisher 401, and the stored transfer paper is bound at two places along the center line and bent at the center line.
Is discharged. If the staple tray or the stitch tray cannot be used for some reason, the transfer paper is discharged to the interrupt tray 406.

Next, a control block of the image forming apparatus of FIG. 4 will be described with reference to FIG. FIG. 6 is a control block diagram of the image forming apparatus of FIG. In FIG. 6, 10
Reference numerals 8 and 109 denote the same parts as in FIG.

An image reading unit 201 includes a lens 1
08, a CCD 109, and an analog signal processing unit 202. An original image is formed on the CCD 109 by the lens 108, and an analog electric signal from the CCD 109 is sampled and held by the analog signal processing unit 202.
The dark level is corrected, converted to a digital signal, and the digitized signal is subjected to shading correction (correction of the variation of the sensor that reads the original and the light distribution characteristics of the original illumination lamp), and the magnification is changed. is there.

Reference numeral 203 denotes an electronic sorter unit. The image sent from the image reading unit 201 is input as black luminance data, and correction processing necessary for an output system such as γ correction, smoothing processing, edge enhancement, image It performs rotation, other processing, processing, and the like.

A printer unit 204 has an exposure control unit 120, an image forming unit 126, and a transfer sheet transfer control unit shown in FIG. 4, and records an image on a transfer sheet based on an input image signal. It is. 205 is a CPU (central pro
cessing unit) is a circuit unit, and a CPU 206 and a ROM
(read only memory) 207 and RAM (random access
memory) 208, and controls the image reading unit 201, the electronic sorter unit 203, and the printer unit 204, and controls the sequence of the apparatus in a comprehensive manner.

FIG. 7 shows the configuration of the electronic sorter unit 203 shown in FIG. In FIG. 7, reference numeral 301 denotes a log conversion unit which outputs a table value corresponding to the luminance data from the image reading unit 201 in accordance with an LUT (lookup table) for converting start-up data into density data, thereby obtaining a luminance. The data is converted into multi-value density data.

Reference numeral 302 denotes a binarization unit, which is a log conversion unit 3
The multi-value density data from 01 is binarized and the density value is set to 8b
It is set to “0” or “255” for it.

Reference numeral 303 denotes a control unit which receives binarized image data from the binarization unit 302 or
Binary image data, which is image data from a computer and is processed by an external I / F processing unit, is input, and a path connecting the control unit of the image storage unit 304 is selected by a command from the main unit. The whole image of the original to be copied is temporarily stored in the image storage unit 304, or image data is sequentially read from the image storage unit 304 and output.

Since the 8-bit image data obtained by the binarization is converted into 1-bit image data of “0” or “1”, the amount of image data stored in the image storage unit 304 is reduced. The image storage unit 304 includes a plurality of storage units including a SCSI controller and a hard disk (external storage device), and a control unit. Each of the plurality of storage units can operate independently.

Reference numeral 305 denotes a smoothing unit which converts 1-bit data read from the image storage unit 304 into 8-bit data by the control unit 308 and changes the image data signal to "0" or "255". It is. 306 is γ
This is a correction unit that performs γ correction on the 8-bit data from the smoothing unit 305. When outputting density data,
The conversion by the LUT in consideration of the characteristics of the printer is performed, and the output is adjusted according to the density value set by the operation unit.

Next, the operation of the electronic sorter unit 203 will be described. The image sent from the image reading unit 201 is Bla
ck is input as luminance data,
1, L for converting luminance data into density data
A table value (density data) corresponding to the luminance data is output according to the UT (lookup table), and the obtained density data is binarized by the binarization unit 302 and converted into 1-bit image data.

However, when an image is binarized, the number of gradations of the image is changed from 256 gradations to two gradations. Therefore, when binarized image data such as a photographic image is binarized, generally,
The image is significantly deteriorated.

Therefore, it is necessary to perform pseudo halftone expression using binary data. Here, an error diffusion method is used as a method for pseudo-halftone expression using binary data.
According to this method, when the density of a certain image is larger than a certain threshold value, it is determined that the density data is “255”. When the density is less than a certain threshold value, it is determined that the density data is “0”. Is a method of distributing the difference between the density data and the binarized data to surrounding pixels as an error signal.

The distribution of the error is performed by multiplying a weight coefficient on a matrix prepared in advance by the error generated by the binarization, and adding the result to surrounding pixels.
As a result, the density average value of the entire image is stored, and the halftone can be represented in a pseudo binary manner.

The binarized image data is selected by the control unit 303 in accordance with a command from the main unit to select a path connected to the control unit of the image storage unit 304, and all images of the original to be copied are stored in the image storage unit 304. The image data is temporarily stored, and the image data is sequentially read from the image storage unit 304.

The image storage unit 304 is operated by a command from the main unit.
The control unit connects to the designated storage unit and writes the image data to the hard disk according to the instruction from the SCSI controller.

The plurality of image data stored in the hard disk are output in an order according to the editing mode specified by the operation unit of the copying machine. For example, in the case of sorting, DF (doc
ument feeder) in order from the last page to the first page of the document bundle, and temporarily stored in the hard disk of the image storage unit 304.

Then, the image data of the document is read from the hard disk of the image storage unit 304 in order from the last page to the first page, and this is repeated and output plural times. Thereby, it can play the same role as a sorter having a plurality of pins.

1 bi read from the image storage unit 304
The t image data is converted by the smoothing unit 305 into 8-bit image data.

The converted image data is obtained as a sum of values obtained by multiplying a coefficient on a predetermined matrix by a density value of a neighboring pixel. It is replaced by a weighted average.

As a result, the binary data is converted into multi-valued data in accordance with the density value of the neighboring pixels, and an image quality closer to the read image can be reproduced. The smoothed image data is input to the gamma correction unit 306.

When outputting the density data, the γ correction unit 306 performs conversion using an LUT in consideration of the characteristics of the printer, and adjusts the output according to the density value set by the operation unit.

FIG. 1 is a flowchart showing an example of the control program stored in the RAM 208 of FIG.

That is, in the bookbinding mode, a division mode in which a plurality of output sheets constituting a pamphlet is divided into a plurality of division sheet bundles and post-processing is performed by the finisher 401 is set. There is an imposition means for controlling the image arrangement so that the image data is divided into two pages on the front and back of each output sheet constituting the divided sheet bundle so that the bundle is arranged in the page order.

The imposition means is constituted by the CPU 206 which executes the control program stored in the RAM 208 of FIG.

The CPU 206 controls the image arrangement based on the control program such that all the pages of the sheets constituting the pamphlet have continuous page numbers for each of the divided sheet bundles. When the number of sheets is larger than the number of sheets that can be folded by the finisher 401, a plurality of output sheets forming a pamphlet are divided into a plurality of divided sheet bundles, and post-processing is performed by a post-processing unit for each divided sheet bundle. The image data is divided into two pages on the front and back of each output sheet constituting the divided sheet bundle so that each divided sheet bundle is arranged in the page order.

Next, the control program will be described in detail. When the brochure mode is selected, the process starts. All originals are stored in the image storage unit 304 (FIG. 7), the number of originals is determined (S501), and the number of output sheets is determined from the number of originals (S503). Next, it is determined whether the number of output sheets is larger than the number of sheets that can be controlled by the stitching unit and the folding unit (S505).

When an affirmative determination is made, originally, FIG.
As shown in FIG. 3A, a sheet formed and output as one bundle of sheets is converted into a stitch unit and a folding unit as shown in FIGS. 2B and 3B. In this case, the sheet is output so as to be smaller than the number of sheets that can be controlled by. At this time, the number n to be divided is calculated by the following assignment formula (S507).

That is, when the number of pages is 18, FIG.
(A), when not dividing as shown in FIG.

Number of used sheets = INT ((number of pages) + (4-
1)) / (3 * 4) = INT ((18 + 3) / 4) = 5
[Sheet]

Here, "INT" is a function for obtaining a number obtained by truncating the number in parentheses below the decimal point.

On the other hand, as shown in FIGS. 2B and 3B, when division is performed for every three sheets, the division number = INT ((the number of pages) + (3 * 4-1) )) /
(3 * 4) = INT ((18 + 11) / 12) = 2
[Sheets] Number of sheets used = 3 + 2 = 5 [sheets]

If the determination is negative, the process proceeds to the next step with the number of divisions n set to 1 (S509).

Here, the counter k for counting the number of divisions is set to 1 and the subsequent division is managed (S5).
11).

The finisher 401 is internally controlled so as to output the k-th divided output sheet to the stitching means and folding means as needed (S513). At this time, when the output sheets are overlapped and folded at the center, control is performed such that two pages of originals are allocated to the front and back sides of the output sheets so that the pages are arranged in the page order, and output is performed until the number of sheets to be stitched is reached (S515). .

Next, stitching is performed on the fold portion when the sheet is folded in half by the finisher 401 (S51).
7), fold in half (S519), and output to the stitch tray (S521).

Here, it is determined whether the discharged bundle of sheets is the last bundle of the division (S523).
The number-of-division counter k is incremented by one, and the process proceeds to S5.
13 (S525).

If the determination is affirmative, it is determined whether the output of the set number of copies has been completed. If the determination is negative, the process proceeds to S50.
5, and if the determination is affirmative, the processing of this mode is terminated (S
527).

As described above, the storage medium storing the program codes of the software for realizing the functions of the above-described embodiments is supplied to the system or the apparatus, and the computer (or CPU or MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads out and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium on which the program code is recorded constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, C
D-ROM (compactdisk ROM), CD-R (compactdisk ROM)
Disk recordable, magnetic tape, non-volatile memory card, ROM (read only memory), etc. can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the operating system (OS) running on the computer based on the instruction of the program code.
Needless to say, a case in which the functions of the above-described embodiments are realized by performing part or all of the actual processing by a ting system or the like is also included.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU provided in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0078]

As described above, according to the image forming apparatus and the control method of the bookbinding mode of the present invention, in the bookbinding mode, a plurality of output sheets constituting a pamphlet are divided into a plurality of divided sheet bundles. Since the post-processing unit sets the division mode in which post-processing is performed, a sheet bundle can be folded with good quality even for a pamphlet including a large number of output sheets.

As a result, the stackability of the sheet bundle can be improved, and the discrimination property can be improved by preventing the sheet bundle from sneaking in.

The imposition means controls the image arrangement for each of the divided sheet bundles so that all of the pages of the sheets constituting the pamphlet have continuous page numbers, thereby providing a plurality of divided sheet bundles. Can be automatically arranged in page order.

According to the bookbinding mode control program of the present invention, it is possible to control various image forming apparatuses in the division mode simply by executing the control program.

Further, if a storage medium on which the bookbinding mode control program of the present invention is recorded is used, the control of the division mode can be easily reproduced only by reading the storage medium.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an example of a bookbinding mode control program for an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state of image allocation at the time of division in FIG. 1;

FIG. 3 is a schematic diagram showing a state before and after division when the division processing of FIG. 1 is performed.

FIG. 4 is a cross-sectional view illustrating a structure of an image forming apparatus to which the present invention is applied.

FIG. 5 is a perspective view showing an appearance of the finisher and the saddle stitching device of FIG. 4;

FIG. 6 is a control block diagram of the image forming apparatus of FIG. 4;

FIG. 7 is a block diagram showing a configuration of an electronic sorter unit shown in FIG.

[Explanation of symbols]

 108 Lens 109 CCD 201 Image reading unit 202 Analog signal processing unit 203 Electronic sorter unit 204 Printer unit 205 CPU circuit unit 206 CPU (imposition means) 207 ROM 208 RAM 304 Image storage unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/00 378 G03G 21/00 382 F term (Reference) 2H027 DA46 DB08 DE07 ED29 EE07 EE08 FA13 FA21 FA30 FA35 FB19 FD08 2H028 BA02 BA14 BB01 BB04 BB06 BD03 2H072 CA01 GA01 JA02 3F108 GA02 GB03

Claims (5)

[Claims] 1. An image forming section for forming an image on the front and back surfaces of a sheet, and a post-processing section for stacking a plurality of output sheets output from the image forming section and folding at the center for bookbinding. An image forming apparatus that controls image arrangement such that image data is divided into two pages each on the front and back of an output sheet so that pamphlets created on a plurality of output sheets are arranged in page order; A division mode is set in which a plurality of output sheets constituting a pamphlet are divided into a plurality of division sheet bundles and post-processing is performed by the post-processing unit. When the division mode is selected, the division sheet bundles are arranged in page order. Is provided with an imposition means for controlling the image arrangement such that the image data is divided into two pages on the front and back sides of each output sheet constituting the divided sheet bundle. Image forming apparatus. 2. The imposition means controls an image arrangement such that all pages of a sheet constituting a pamphlet have continuous page numbers for each of the divided sheet bundles. The image forming apparatus according to claim 1. 3. An image forming section for forming an image on the front and back surfaces of a sheet, and a post-processing section for stacking a plurality of output sheets output from the image forming section and folding at the center for bookbinding. In an image forming apparatus that controls the image arrangement so that image data is divided into two pages each on the front and back of an output sheet so that a pamphlet created on a plurality of output sheets is arranged in page order, the number of output sheets is When the number of sheets that can be processed by the post-processing unit is larger than the number of sheets that can be processed, the plurality of output sheets forming the pamphlet are divided into a plurality of divided sheet bundles, and post-processing is performed by the post-processing unit for each divided sheet bundle. A bookbinding mode control method for an image forming apparatus, wherein image data is divided into two pages on the front and back sides of each output sheet constituting a divided sheet bundle so that the bundle is arranged in page order. 4. When the bookbinding mode is started, all original images are stored in the image storage unit, the number of output sheets is obtained from the number of original images, and the number of output sheets is determined by the post-processing unit. In the case of an affirmative determination, the number of divisions of a plurality of output sheets constituting a pamphlet into a divided sheet bundle for each predetermined number is calculated, and in the case of a negative determination, the number of divisions n is set to 1 And proceeds to the next step. The counter k for counting the number of divisions is set to 1 and k
The output paper of the third division is controlled to be output to the post-processing unit at any time. At this time, when the output papers are overlapped and folded at the center, two pages of the original image are printed on the front and back sides of the output paper in the page order. Image forming is performed until the number of sheets to be post-processed is controlled, and sheets are output to the post-processing unit. After that, the output sheets are folded in half and discharged by the post-processing unit. Is determined as the final bundle of the division. If the determination is negative, the division number counter k is incremented by 1 and the next divided sheet bundle is processed. If the determination is affirmative, the output of the set number of copies is completed. A bookbinding mode control program for an image forming apparatus, wherein the bookbinding mode control program repeats the bookbinding procedure if the determination is negative, and ends the bookbinding mode processing if the determination is affirmative. 5. A storage medium on which the bookbinding mode control program according to claim 4 is recorded.