JP2007153579A - Paper processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper processor for manufacturing a high-quality pamphlet. <P>SOLUTION: This paper processor is characterized by having an image forming device 2 forming an image on a plurality of paper, a post-processor 5 for making the pamphlet of forming a binding hole by boring holes in a position separate by a predetermined distance from the folding-up back by superposing the plurality of paper, and a control circuit 26 for making the image forming device 2 form the image in an image forming area being a more separate position from the center on the center near edge of a double spread as paper positioned on the cover side of the pamphlet by being folded up by the post-processor 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper processing apparatus for processing paper.

2. Description of the Related Art Conventionally, some paper processing apparatuses represented by printers and copiers have a booklet production unit for producing a booklet from paper on which an image is formed, in addition to an image formation unit that forms an image on paper. . In the booklet production unit, paper is stacked and folded for booklet production. Here, in the paper processing device, in order to make it easy to bind the produced booklet into a file, the booklet production unit applies the folded paper to the folded paper. There are some that punch holes (for example, refer to Patent Documents 1 and 2). In addition, some paper processing apparatuses cut out the edges of the folded paper in the booklet preparation unit. In order to prevent the margins from becoming uneven due to the trimming of the edges, Patent Document 3 discloses a technique of spreading the area on the paper where the image is formed and shifting it to the center side. Has been.
JP 2001-151406 A JP 2003-276359 A Japanese Patent Laid-Open No. 08-324064

  A booklet in which binding holes are formed on a folded sheet is easy to bind and organize in a file. However, if an image is formed on the part where the hole is perforated, a part of the image is formed by perforation. There is a problem that the quality of the booklet deteriorates due to the lack. Further, in the state where the binding tool of the file is inserted into the binding hole and the booklet is bound into the file, the image formed from the center of the spread to the position of the hole cannot be visually recognized. In the technique of Patent Document 7, the omission of an image near the edge when the edge of the paper is trimmed is prevented, but a binding hole is formed because the area where the image is formed is moved to the center of the spread of the paper. It is not possible to improve the quality deterioration of the booklet due to missing images in the area.

  In view of the above circumstances, an object of the present invention is to provide a paper processing apparatus that produces a high-quality booklet.

The paper processing apparatus of the present invention that achieves the above-described object provides:
An image forming unit that forms images on a plurality of sheets;
A booklet production unit for producing a booklet in which a binding hole is formed by punching a hole at a position separated from the back by a predetermined distance by stacking and folding the plurality of sheets.
In the image forming section, the edge that is closer to the center of the spread is located in the image forming area that is more distant from the center, as the sheet is positioned on the cover side of the booklet by being folded by the booklet preparation section. And a control unit for forming an image.

  When a plurality of sheets are folded and a hole is perforated, the distance from the center of the spread to the hole perforated on the sheet increases as the sheet is located on the cover side of the booklet. Since the edge of the image forming area is located farther from the center of the paper that will be located on the cover side of the booklet, the image is appropriately separated from this hole depending on the position of the hole that differs for each paper. It is formed. Therefore, it is possible to prevent a situation where an image is lost due to punching or cannot be visually recognized when bound to a file, and the quality of the booklet is improved.

  In the sheet processing apparatus of the present invention, the control unit obtains sheet number information indicating the number of sheets constituting the booklet, and the image forming unit has an edge near the center of the spread from the center. It is preferable that an image is formed in the image forming area located at a distance corresponding to the number of sheets indicated by the sheet number information.

  The distance from the center of the spread to the perforated hole on the paper constituting the booklet varies depending on the number of sheets constituting the booklet, but here, the image forming area where the image is formed constitutes the booklet. By being located at a distance corresponding to the number of sheets, an image is formed in an appropriate area according to the number of sheets.

  In the paper processing apparatus of the present invention, the control unit obtains paper thickness information indicating the thickness of the paper constituting the booklet, and the image forming unit has an edge closer to the center of the spread. It is preferable that an image is formed in an image forming area located at a distance corresponding to the thickness of the sheet represented by the sheet number information.

  The distance from the center of the spread to the perforated hole on the paper constituting the booklet varies depending on the thickness of the paper constituting the booklet. Here, the image forming area where the image is formed is located at a distance corresponding to the thickness of the paper constituting the booklet, so that the image is formed in an appropriate area according to the number of sheets.

In the sheet processing apparatus of the present invention, the image forming unit scans the surface of the image carrier and the surface of the image carrier with exposure light in the direction of the rotation axis of the image carrier. An exposure device for forming an electrostatic latent image on the surface is provided. The electrostatic latent image is developed with toner to obtain a toner image, and the toner image is finally transferred and fixed on the paper. Forming an image consisting of a fixed toner image,
The controller determines an exposure start timing for causing the exposure device to start forming an electrostatic latent image based on the degree to which the booklet preparation unit positions the paper on the cover side of the booklet. It is preferable that the formation of an electrostatic latent image is started at this exposure start timing.

  The position of the edge near the center of the image forming area can be changed according to the exposure start timing at which the exposure device starts forming the electrostatic latent image. Here, the position of the edge near the center of the image forming area is accurately controlled by controlling the timing at which the formation of the electrostatic latent image is started at the exposure start timing obtained based on the position in the booklet of the paper. It becomes possible to control.

The paper processing apparatus of the present invention includes a paper transport unit that transports paper along a transport path that passes through the image forming unit,
Based on the extent to which the booklet preparation unit positions the paper on the cover side of the booklet, the control unit obtains a transport start timing for starting the paper transport to the paper transport unit, and sends the paper transport unit to the paper transport unit. It is preferable that the conveyance of the sheet is started at the conveyance start timing.

  Since the position of the edge near the center of the image forming area also varies depending on the conveyance start timing at which the sheet conveying unit starts conveying the sheet, the position of the edge near the center of the image forming area is also controlled using the conveyance start timing. be able to.

  Further, in the paper processing apparatus of the present invention, the control unit is configured such that the sheet that is positioned on the cover side of the booklet by being folded by the booklet preparation unit on the image forming unit is from the center of the spread to the spread end. It is preferable to form an image having a short width in the direction of travel.

  The paper that is located on the cover side of the booklet has a smaller width in the direction from the center of the spread to the spread end, so that the paper that is located on the cover side of the booklet has a spread of the image forming area. Even if the center edge is located farther from the center, it is possible to match the position of the edge of the spread edge on each sheet. That is, the width of the margin from the end of the booklet spread can be kept almost constant for each sheet.

  In the paper processing apparatus of the present invention, the control unit may expose the surface of the image carrier to the exposure unit based on the degree that the booklet preparation unit positions the paper on the cover side of the booklet. It is preferable that the scanning speed for scanning is obtained and the surface of the image carrier is scanned with the exposure light at the scanning speed by the exposure light to form an electrostatic latent image.

  The width of the image in the direction from the center of the double spread to the double spread edge varies depending on the scanning speed at which the exposure device scans the surface of the image carrier with the exposure light. Here, since the scanning speed at which the exposure device scans the surface of the image carrier is obtained based on the position of the paper on the booklet, the width of the image can be accurately controlled.

  In the sheet processing apparatus of the present invention, the control unit obtains the sheet conveyance speed of the conveyance unit based on the degree to which the booklet production unit positions the sheet on the cover side of the booklet, It is preferable to carry it at this carrying speed.

  The width of the image in the direction from the center of the spread toward the spread end differs depending on the paper conveyance speed of the conveyance unit. Therefore, the width of the image can be accurately controlled even when the sheet conveyance speed is obtained based on the position of the sheet in the booklet.

  As described above, according to the present invention, a paper processing apparatus for producing a high-quality booklet is realized.

  Embodiments of a sheet processing apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an image forming system which is an embodiment of a paper processing apparatus of the present invention.

  The image forming system 1 includes an image forming apparatus 2 that forms an image on a sheet, and a post-processing apparatus 5 that performs post-processing of the sheet on which the image is formed by the image forming apparatus 2.

  The image forming apparatus 2 is an apparatus that forms an image on a sheet by an electrophotographic method and conveys the image to a post-processing apparatus 5. The image forming apparatus 2 includes an operation panel 21 on which information is input by a user operation. ing.

  FIG. 2 is a diagram showing an outline of the image forming apparatus of the image forming system shown in FIG.

  The image forming apparatus 2 includes an automatic document supply device 22, an image input device 23, an image output device 24, and a paper supply unit 25.

  The automatic document feeder 22 supplies the stacked documents one by one to the image input device 23.

  The image input device 23 includes an imaging unit 231, reads a document supplied from the automatic document feeder 22, and outputs an image signal.

  The image output device 24 includes a scanner 241, a photosensitive drum 242, a charger 243 that uniformly charges the photosensitive drum 242, a developing unit 244 that develops the electrostatic latent image into a toner image, and a transfer that transfers the toner image onto a sheet. The unit 245 includes a cleaner 246 that collects residual toner that has not been transferred. An image signal from the image input device 23 is converted into a signal by exposure light in a laser output unit 241a included in the scanner 241, and rotates through a polygon mirror 241b, an fθ lens 241c, and a reflection lens 241d. An electrostatic latent image based on the original image is formed on the drum 242. The scanner 241 starts exposure at a specified exposure start timing, and forms an electrostatic latent image by scanning the surface of the photosensitive drum 242 with exposure light at a specified scanning speed. The image signal can also be input from a computer externally connected to the image forming apparatus 2 (see FIG. 4). The electrostatic latent image is formed by the scanner 241 scanning the surface of the photosensitive drum 242 with exposure light in the direction of the rotation axis of the photosensitive drum 242. The electrostatic latent image is developed to obtain a toner image. After the toner image is transferred to the paper, the photosensitive drum 242 is charged by the charger 243 after the residual toner is removed by the cleaner 246. The photosensitive drum 242 corresponds to an example of an image carrier according to the present invention, and the scanner 241 corresponds to an example of an exposure device according to the present invention. On the other hand, when the transfer is completed, the sheet is sent to the fixing device 247 to fix the toner image. As a result, an image is formed on the paper. Note that in the image formation of a plurality of sheets constituting the booklet, images are formed in order from the side opposite to the cover of the booklet, that is, the sheet constituting the innermost side of the booklet.

  The sheet supply unit 25 includes a tray 258 (258a, 258b, 258c) on which sheets are stacked, a transport roller 259 that transports the sheets stacked on the tray 258 along a transport path R that passes through the image output device 24, and And an adjusting roller 250. The adjustment roller 250 conveys the sheet toward the transfer unit 245. The conveyance roller 259 and the adjustment roller 250 correspond to an example of a paper conveyance unit according to the present invention.

  Here, returning to FIG. 1, the description will be continued.

  The post-processing device 5 stores paper, inserter 6 for additional insertion as a book cover, booklet finisher 7 for bundling, saddle stitching and folding, trimmer 8 for trimming booklet sides, and square for finishing the booklet. A fold device 9 and a stacker 10 on which a booklet is loaded are provided. The post-processing apparatus 5 corresponds to an example of a booklet production unit referred to in the present invention.

  The booklet finisher 7 includes a paper tray 71, a pair of folding rollers 72, and an extrusion unit 73. The sheets conveyed from the image forming apparatus 2 through the inserter 6 are bundled on the sheet tray 71. On the paper tray 71, the paper is stacked in order from the side opposite to the cover of the booklet, that is, the innermost one. The extruding unit 73 is provided so as to be movable between the position of the center of the sheet on the sheet tray 71 and the position between the pair of folding rollers 72. When the portion is pushed out between the pair of folding rollers 72, the paper pushed out between the folding rollers 72 is folded in two. The folded paper is conveyed to the trimmer 8 and the square folding device 9 with the portion corresponding to the back of the booklet at the top. The trimmer 8 includes a cutter 81 that cuts and aligns sheets. The cutter 81 is provided so as to be movable up and down. By moving, the cutter 81 aligns a portion of the paper corresponding to the booklet edge.

  The square fold device 9 includes a stop plate 94 for positioning the paper, a clamping jaw 95 for sandwiching the paper positioned by the stop plate 94, a roller 96 for crushing and flattening a portion of the paper corresponding to the back of the booklet, A punch 97 for punching holes in the folded paper and a carry-out roller 98 for carrying the booklet to the stacker are provided.

  FIG. 3 is a diagram showing an outline of functions of the square fold device.

  The clamping jaw 95 sandwiches the folded sheet P1 from the cover side, and the roller 96 forms a portion P1a corresponding to the back of the booklet of the sheet sandwiched by the clamping jaw 95 along the portion P1a. And flatten by crushing. Whether or not to flatten the back with the square fold device 9 depends on the user's selection.

  FIG. 4 is a diagram showing an outline of the punch function.

  The folded sheet P1 is then conveyed to the punch 97 as shown in part (a) of FIG. 4, and positioned and stopped at the portion corresponding to the spine. A blade 97a is attached to the punch 97, and when the punch 97 sandwiches the paper P1, two holes are punched by a predetermined distance from the back by the blade 97a. As a result, as shown in part (b) of FIG. 4, a booklet B1 with a binding hole P1h is produced. Thereafter, the booklet B <b> 1 is unloaded onto the stacker 10 by the unloading roller 98 and stacked on the stacker 10.

  FIG. 5 is a block diagram showing an electrical configuration of the image forming system shown in FIG.

  The image forming apparatus 2 includes a control circuit 26 that controls the operation of the entire image forming system 1. Although not shown, the control circuit 26 is a central processing unit (CPU) that controls the overall operation of the image forming system based on a program, a ROM that stores programs and tables, and a temporary storage area in the CPU. A RAM to be provided and an interface circuit for relaying signals between the outside of the control circuit 26 and the CPU are provided. A user personal computer 40 is externally connected to the image forming apparatus 2.

  When an image formation instruction is sent to the control circuit 26 from the operation panel 21 or an externally connected user's personal computer 40, the control circuit 26 includes the automatic document feeder 22, the image input device 23, and the image input device 23. The image output device 24 and the paper supply unit 25 are controlled to form an image on the paper. Further, the control circuit 26 controls operations of the booklet finisher 7, the trimmer 8, the square folding device 9, and the stacker 10. For example, the control circuit 26 controls the operation of the punch 97 incorporated in the square folding device 9. The control circuit 26 corresponds to an example of a control unit referred to in the present invention.

  Here, in the image forming system 1 according to the present embodiment, as the sheet is folded by the booklet finisher 7 and positioned on the cover side of the booklet, the center edge of the spread of the image forming area where the image is formed is closer. Since the position is further away from the center, the distance from the center of the spread to the hole on the paper and the image forming area will be described with reference to FIGS.

  FIG. 6 is a diagram illustrating a state where the sheet is folded.

  As shown in FIG. 6, a hole P2h having a diameter b is formed in the folded sheet P2 at a predetermined distance a from the back P2a. The distance a from the back to the hole and the diameter b of the hole P2h are typically 10 mm and 7 mm, respectively. Here, if an image is formed in a region from the hole punched in the folded paper P2 to the back P2a, a part of the image is lost due to the punching, or the paper P2 is bound to a file as a booklet. When plugged in, it cannot be opened and viewed. An area from the hole P2h to the back P2a is an area where image formation is prohibited.

  FIG. 7 is a cross-sectional view schematically showing a part of the paper shown in FIG.

  In the example shown in FIG. 7, the paper P2 is a state in which 20 sheets of paper P201 to P220 are overlapped and folded. Of the sheets P201 to P220, the sheets P203 to P218 are not shown.

  The size of the area where image formation is prohibited differs for each of the sheets P201 to P220. Each of the sheets P201 to P220 is further folded so as to have a curved surface so as to cover the inner sheet. For example, in the most cover-side paper P201, the distance from the center of the paper to the edge of the hole P2h (hereinafter referred to as “prohibited distance”) M101 that defines the area where image formation is prohibited is a curved surface portion (arc portion in the figure). ) And the distance f of the plane portion (straight line portion in the figure). When the folded sheet P2 is composed of 20 sheets having a thickness of 0.087 mm, the radius d of the arc is substantially equal to the thickness of the 20 sheets, and 0.087 × 20 = 1. 74 mm. Therefore, the distance e of the curved surface portion is 2dπ / 4 = 2.73 mm. Further, the distance f of the plane portion is a + b / 2−d = 10 + 3.5−1.74 = 11.76 mm. Therefore, the forbidden distance M101 is e + f = 14.49 mm. Next, in the sheet P202 that is one sheet inside the sheet P201, the radius d of the arc is smaller than the sheet P201 by the thickness of one sheet, and the forbidden distance of the sheet P202 is based on the radius d of the arc. M102 is required. For the papers P203 to P220 that are further inside than the paper P202, the prohibited distances M103 to M120 can be obtained similarly to the paper P202. That is, in the state where the sheet is composed of 20 sheets having a thickness of 0.087 mm, the forbidden distance from the innermost sheet P220 to the Nth sheet is the expression (π × 0.087 × N / 2) +11.76. Can be obtained by calculation.

  FIG. 8 is a table showing the prohibited distance for each sheet.

  In FIG. 8, forbidden distances M101 to M120 when 20 sheets having a thickness of 0.087 mm are folded are shown for each sheet. In the table of FIG. 8, the value corresponding to the column “20th sheet” corresponds to the prohibited distance M101, and sequentially corresponds to M102, M103,.

  FIG. 9 is a cross-sectional view schematically showing a state in which a sheet having a thickness different from that shown in FIG. 7 is folded.

  A sheet P3 shown in FIG. 9 is a state in which 20 sheets of sheets P301 to P320 are overlaid and folded. Here, assuming that the thickness of each of the sheets P301 to P320 is t, the forbidden distance from the innermost sheet P220 to the Nth sheet in the state where the sheet is composed of 20 sheets of thickness tmm is It is obtained by calculating the formula (π × t × N / 2) + a + b / 2−20t. As described above, the prohibited distance for each sheet can be obtained by calculation from the number of sheets constituting the booklet, the position of the sheet, and the thickness of the sheet. Even if the number of sheets to be folded is other than 20, the same method can be applied.

  Next, a procedure for determining the distance from the center of the edge near the center of the spread in the image forming area where the image is formed according to the prohibited distance will be described.

  FIG. 10 is a diagram illustrating an image forming area on a sheet.

  As an example of the sheet, part (a) in FIG. 10 shows the sheet P220 that is located on the innermost side opposite to the cover side of the booklet, and part (b) shows the sheet P220 on the most cover side of the booklet. A sheet P201 to be positioned is shown. Images are formed on the paper P220 and the paper P201 in the direction indicated by the arrow Z in the image output device 24. The paper P220 and the paper P201 are transported in the direction opposite to the direction indicated by the arrow Z by the transport roller 259 and the adjustment roller 250 shown in FIG. Each side of the sheet P220 and the sheet P201 is folded to correspond to two pages of the booklet. Therefore, the image forming regions PV1, two corresponding to two pages of the booklet are respectively included in the sheet P220 and the sheet P201. PV2 is arranged. Further, the center C of the paper is the center of the spread of the booklet.

  As shown in FIG. 10, on the paper, the image forming areas PV1 and PV2 where the image is formed have distances from the center C of the edges PV1a and PV2a closer to the center from the center of the area where image formation is prohibited. It is a distance obtained by adding a certain margin width m to the width. For example, as shown in part (a) of FIG. 9, in the paper P220 that is located on the inner side opposite to the cover side of the booklet, the distance between the edges PV1a and PV2a from the center C of the paper P220 is prohibited. This is a distance obtained by adding a margin width m to the distance M120. In addition, even in the paper P201 that is located on the cover side of the booklet shown in Part (b) of FIG. 9, the distance from the center C of the paper P201 to the edges PV1a and PV2a is set to the prohibited distance M101 with the margin width m. It is the added distance.

  Here, as described above, a sheet that is positioned on the cover side of the booklet by being folded has a larger prohibition distance. Therefore, a sheet PV that is positioned on the cover side of the booklet has a margin PV1a closer to the center of the spread. , PV2a are further away from the center C of the paper.

  In the present embodiment, the positions of the edges PV1a and PV2a of the image forming areas PV1 and PV2 on the paper are determined such that the scanner 241 scans the surface of the photosensitive drum 242 with the exposure light in the rotation axis direction of the photosensitive drum 242. Controlled by start timing. FIG. 9 shows an image forming area on the paper. Here, the image on the paper is obtained by transferring and fixing the toner image obtained on the surface of the photosensitive drum 242. The toner image is obtained by developing an electrostatic latent image formed by the scanner 241 scanning the surface of the rotating photosensitive drum 242 with exposure light. Therefore, FIG. 9 also shows a state in which the electrostatic latent image formed on the surface of the photosensitive drum 242 by being scanned with the exposure light by the scanner 241 at the same time as the image forming area on the sheet is developed in a plane. It will be. In this case, the direction in which the scanner 241 scans the surface of the photosensitive drum 242 with the exposure light in the rotation axis direction of the photosensitive drum 242 corresponds to the direction indicated by the arrow Y. On the other hand, the electrostatic latent image is formed in the direction indicated by the arrow Z with the passage of time as the photosensitive drum 242 rotates. That is, the arrow Z in FIG. 9 also shows the time axis direction when the scanner 241 forms an electrostatic latent image on the surface of the photosensitive drum 242.

  Here, the control circuit 26 (see FIG. 4) adds a fixed margin width m to the distance between the edges PV1a and PV2a of the image forming areas PV1 and PV2 near the center of the sheet from the center C of the sheet P220. The exposure start timing in the scanner 241 is set so that the distance becomes the same. That is, when the direction indicated by the arrow Z in FIG. 9 is the time axis direction, the exposure start timing ta1 of the electrostatic latent image for forming the image of the image forming area PV1 shown in part (a) The exposure start timing ta0, which is a reference when the hole is not punched by the punch 97, is set earlier than the time required for the surface of the body drum 242 to move the forbidden distance M120. The exposure start timing ta1 is obtained by calculation from the peripheral speed of the photosensitive drum 242. By starting exposure at an exposure start timing ta1 earlier than the exposure start timing ta0, the end of exposure of the electrostatic latent image to the image in the image forming area PV1 is also accelerated. As a result, when the electrostatic latent image formed on the surface of the photosensitive drum 242 is developed and transferred to the paper P220, the distance from the center C of the paper P220 to the edge PV1a near the center of the image forming region PV1. Is a distance obtained by adding the margin width m to the prohibited distance M120. On the other hand, the exposure start timing tb1 of the electrostatic latent image for forming the image of the image forming area PV2 of the paper P220 is set to the hole by the punch 97 for the time when the surface of the photosensitive drum 242 moves the prohibited distance M120. The exposure is started later than the exposure start timing tb0, which is a reference when the perforation is not performed. Thereby, when the electrostatic latent image on the surface of the photosensitive drum 242 is developed and transferred to the paper P220, the distance from the center C of the paper P220 to the edge PV2a near the center of the image forming region PV2 is prohibited. This is a distance obtained by adding a margin width m to the distance M120. For each of the other sheets P202 to P219, the exposure start timings ta1 and tb1 are advanced or delayed from the exposure start timings ta0 and tb0 according to the prohibited distances M102 to M119, so that the center of the image forming area PV1 is reached. The distance from the center C of the near edge PV1a and the distance from the center C of the edge PV2a near the center of the image forming area PV2 are distances obtained by adding the margin width m to the prohibited distances M102 to M119. In this way, the timing of the start of electrostatic latent image formation is controlled at a different exposure start timing for each position on the paper booklet, so that the position of the edge near the center of the image forming area can be accurately determined. Can be controlled.

  Next, an image forming / binding process in the image forming system 1 will be described.

  FIG. 11 is a flowchart showing image forming / binding processing in the image forming system.

  The image forming / binding process shown in FIG. 11 is realized by the control circuit 26 shown in FIG. 4 controlling the operation of each unit based on a program. Here, the flowchart of FIG. 11 will be described with reference to FIG.

  In the image forming / binding process, the control circuit 26 first performs a paper information acquisition process (step S11). The control circuit 26 causes the operation panel 21 to display a message prompting the user to input information indicating the thickness of each size of paper stored in the tray 258 and the inserter 6. When the operator operates the operation panel 21 to input information indicating the thickness, the input information is supplied to the control circuit 26.

  Next, the control circuit 26 performs bookbinding condition setting processing (step S12). The control circuit 26 displays a message on the operation panel 21. This message prompts the user to input information about the number of sheets constituting the booklet, the sheet size to be used, and the presence or absence of square folding (the strength when square folding is present). . When the user operates the operation panel 21 to input information on the number of sheets, the sheet size, and the strength of the square fold processing, the input information is supplied to the control circuit 26 and a booklet production job is instructed. Is done. At this time, the control circuit 26 obtains sheet number information indicating the number of sheets constituting the booklet from the user. Further, the control circuit 26 obtains sheet thickness information indicating the sheet thickness corresponding to the used sheet size from the information on the used sheet size. A tray for storing the corresponding sheet is selected according to the sheet size information.

  Next, the control circuit 26 performs an exposure start timing calculation process (step S13). The exposure start timing is a timing at which the scanner 241 starts scanning the surface of the photosensitive drum 242 with exposure light, and is different for each sheet constituting the booklet. The control circuit 26 calculates the prohibition distance for each position in the booklet of the sheet as shown in the table of FIG. 8, for example, from the number of sheets indicated by the sheet number information and the sheet thickness indicated by the sheet thickness information. An exposure start timing is calculated according to the calculated prohibited distance. Two exposure start timings ta1 and tb1 are calculated for each sheet corresponding to the two image forming areas PV1 and PV2 arranged on each sheet.

  Next, the control circuit 26 performs an exposure timing setting process (step S14). Here, from the exposure start timing obtained for each sheet in step S13, the position in the booklet of the sheet to be imaged next, that is, the number of the sheet from the cover of the booklet is determined. Select and set the exposure start timing. As a result, the exposure start timing changes for each sheet, and the positions of the edges PV1a and PV1b of the image forming areas PV1 and PV2 change.

  Next, the control circuit 26 performs an image forming process (step S15). The control circuit controls each device of the image forming apparatus 2 to form an image on one sheet. For example, the photosensitive drum 242 is rotated at a constant rotational speed, and the scanner 241 is caused to start forming an electrostatic latent image on the photosensitive drum 242 at the timing set in step S14. Further, the conveyance roller 259 and the adjustment roller 250 are caused to start conveying the paper at a predetermined conveyance start timing.

  When image formation on one sheet is completed, the control circuit 26 determines whether or not the count value of the number of sheets has reached the number of sheets constituting the booklet (step S16). If it is determined that an image has been formed on the number of sheets of the booklet, the bookbinding process in step S17 is performed. If it is determined that the number of sheets of the booklet has not been reached, the process from step S14 is performed. By repeating the process, an image is formed in an image forming area corresponding to the position of the sheet in the booklet for all the sheets constituting the booklet.

  In step S17, a bookbinding process is performed. Specifically, the booklet finisher 7 is made to bundle the sheets, and the sheets are stacked and then folded and folded. Further, the trimmer 8 causes the side of the folded paper corresponding to the booklet edge to be trimmed, and the square folding device 9 flattens the portion corresponding to the back of the booklet according to the user's selection. Further, a hole is drilled in the punch 97 of the square fold device 9. Thereby, the booklet in which the binding hole is formed is produced.

  Next, the control circuit 26 determines the number of books (step S18). It is determined whether or not the number of bound booklets has reached the designated number. If it is determined that the specified number of books has not been reached, the process from step S14 is repeated to continue producing the booklet. If it is determined that the specified number of books has been reached, the image forming / binding process is performed. Exit.

  According to the present embodiment, as shown in FIG. 10, in the image forming areas PV1 and PV2 where images are formed, the edges PV1a and PV1b near the center of the spread are separated from the center, and the image is a portion where a hole is perforated. It is formed in a region away from. Moreover, since the edge of the image forming area PV1a, PV1b is more distant from the center as the paper is located closer to the cover side of the booklet, the image is perforated appropriately depending on the position of the paper in the booklet. Formed away from the hole. Therefore, it is possible to prevent a situation in which an image is lost due to punching or cannot be visually recognized when bound to a file, and the quality of a booklet can be improved.

  Further, the edge of the image forming area PV1a, PV1b is more distant from the center of the paper that is located on the cover side of the booklet, so that when the booklet is opened, the image position is at the center of the spread. The quality of the booklet is high because it matches.

  Further, the edges PV1a and PV1b of the image forming area where the image is formed are located at a distance corresponding to the number and thickness of the sheets constituting the booklet, so that the booklet differs depending on the number and thickness of the sheets. It is formed in a suitable region according to the thickness of

  In this embodiment, the example of the photosensitive drum is described as the image carrier, but the image carrier may be a photosensitive belt. Further, even when exposure devices having four colors of Y (yellow), M (magenta), C (cyan), and K (black) or more are used, the exposure devices at a plurality of locations are controlled in the same manner. Good.

[Second Embodiment]
In the above-described embodiment, the scanner 241 is controlled to start the formation of the electrostatic latent image at the calculated exposure start timing. However, the change of the position of the edge PV1a of the image forming area is the start of the exposure of the scanner 241. It is not limited to the timing control. Next, a second embodiment of the present invention in which the control of the sheet conveyance start timing by the adjustment roller 250 is used together will be described. In the description of the following embodiments, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 12 is a diagram illustrating an image forming area on a sheet according to the second embodiment of the present invention.

  As an example of the sheet, part (a) in FIG. 12 shows the sheet P220 that is located on the innermost side opposite to the cover side of the booklet, and part (b) shows the sheet on the most cover side of the booklet. A sheet P201 to be positioned is shown. Here, the paper P220 and the paper P201 are transported in the direction opposite to the direction indicated by the arrow Z by the transport roller 259 and the adjustment roller 250 shown in FIG.

  In the second embodiment, as the sheet is located closer to the cover side of the booklet, the edge closer to the center of the spread is placed further away from the center C of the sheet, so the conveyance start timing at the adjustment roller 250 is increased. Adjust for each paper.

  In the second embodiment, the control circuit 26 (see FIG. 4) is configured such that the distance from the center C of the sheet P220 of the edge PV1a near the sheet center of the image forming region PV1 adds a certain margin width m to the prohibited distance. The conveyance start timing at the adjusting roller 250 is set so that the distance becomes equal. That is, assuming that each position of the conveyed paper is in the direction indicated by the arrow Z in FIG. 12 is the direction of time for passing the adjustment roller 250, the timing at which the adjustment roller 250 starts to convey the paper P220 shown in part (a). The time tc1 is set later than the conveyance start timing tc0 when the hole is not punched by the punch 97 by the time for which the surface of the photosensitive drum 242 moves the distance of the prohibited distance M120. The conveyance start timing tc1 is obtained by calculation from the peripheral speed of the photosensitive drum 242. By starting the conveyance of the paper at this late conveyance start timing tc1, the transfer of the toner image in the image forming area PV1 to the paper is relatively accelerated. As a result, in the image transferred and fixed on the paper P220, the distance from the center C of the paper P220 of the edge PV1a closer to the center of the image forming area PV1 becomes a distance obtained by adding the margin width m to the prohibited distance M120.

  In the second embodiment, the control circuit 26 calculates and sets the conveyance start timing together with the exposure start timing in the processing of step S13 and step S14 in FIG.

  In this way, by controlling the timing at which the conveyance of the sheet is started at the conveyance start timing obtained based on the position of the sheet in the booklet, the electrostatic latent image formation start timing in the first embodiment is controlled. As with the above control, the position of the edge near the center of the image forming region can be accurately controlled. In the second embodiment, since the paper conveyance start timing is changed, the movement of the position in the image forming area PV1 also occurs in the image forming area PV2. For the image forming area PV2, the electrostatic latent image formation start timing tb1 is further delayed in consideration of the delay in the paper conveyance start timing.

  In this embodiment, an example in which the conveyance start timing is adjusted by the adjustment roller has been described. However, a sensor for adjusting timing is provided at the position of the adjustment roller so that the paper does not stop temporarily by the adjustment roller, and the sensor detects the leading edge of the paper. By accelerating and decelerating the paper during the period from the detection until the image forming area PV1 reaches the photosensitive drum, the time for the image forming area PV1 to reach the photosensitive drum is controlled, and the exposure start timing is adjusted. Also good. Since the sheet conveyance start timing is changed, the movement of the position in the image forming area PV1 also occurs in the image forming area PV2, but the image forming area PV2 passes after the image forming area PV1 passes the photosensitive drum. By accelerating and decelerating the paper during the period until it reaches the photosensitive drum, the time for the image forming area PV2 to reach the photosensitive drum may be controlled, and the exposure start timing after the center C may be adjusted.

[Third Embodiment]
In the above-described embodiment, the electrostatic latent image is formed on the photosensitive drum 242 at a constant speed. That is, the scanner 241 exposes the surface of the photosensitive drum 242 in the direction of the rotation axis of the photosensitive drum 242. However, the position of the edge PV1a of the image forming area can be changed by changing the scanning speed of the scanner 241. Subsequently, a third embodiment of the present invention in which the scanning speed is controlled by the scanner 241 will be described. In the description of the following embodiments, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 13 is a diagram showing an image forming area on a sheet in the third embodiment of the present invention.

  As an example of the sheet, part (a) in FIG. 13 shows the sheet P220 that is located on the innermost side opposite to the cover side of the booklet, and part (b) shows the sheet on the most cover side of the booklet. A sheet P201 to be positioned is shown. Here, images are formed on the paper P220 and the paper P201 in the direction indicated by the arrow Z in the image output device 24.

  In the third embodiment, the scanner 241 exposes the surface of the photoconductive drum 242 in the direction of the rotation axis of the photoconductive drum 242 (the direction indicated by the arrow Y in the figure) as the paper is positioned closer to the cover side of the booklet. Increase the scanning speed with light.

  In the third embodiment, the control circuit 26 (see FIG. 4) adds a fixed margin width m to the distance from the center C of the paper P220 to the edge PV1a near the paper center of the image forming region PV1. The scanning speed of the scanner 241 is set so that the distance becomes the same. That is, assuming that the direction indicated by the arrow Z in FIG. 13 is the time axis, the scanning speed of the scanner 241 is the same as the time when the scanning of the image forming area PV1 is completed and the surface of the photosensitive drum 242 moves the prohibited distance M120. Make it faster to be faster. The speed to be added is obtained by calculation from the peripheral speed of the photosensitive drum 242. By scanning the scanner 241 at this high scanning speed, the exposure end of the electrostatic latent image with respect to the image in the image forming area PV1 is accelerated while the exposure start timing or the sheet conveyance start timing is kept constant. That is, the size of the electrostatic latent image formed on the photosensitive drum 242 is reduced. As a result, the image transferred and fixed on the sheet P220 has a shorter width in the direction from the center of the spread toward the spread end, and the distance of the edge PV1a closer to the center of the image forming area PV1 from the center C of the sheet P220 is This is the distance obtained by adding the margin width m to the prohibited distance M120.

  As described above, by controlling the scanning speed of the scanner 241 at the scanning speed obtained based on the position of the paper in the booklet, the electrostatic latent image formation start timing in the first embodiment is controlled. Similarly to the above, the position of the edge near the center of the image forming area can be accurately controlled. In addition, according to the third embodiment, as the position of the edge near the center is changed, the width of the image becomes shorter in the direction from the center of the spread toward the spread end, so that it is closer to the spread end of the image forming area. The position of the edge is constant for all sheets.

  In the third embodiment, since the scanning speed of the scanner 241 is changed, the formed image has a short width not only in the direction from the center of the spread toward the spread end but also in the direction of the back of the booklet. Become. In the third embodiment, since the scanning speed of the scanner 241 is changed, the electrostatic latent image formation start timing is set in the image forming area PV2 in consideration of the fact that the width of the image is shortened. Need to delay.

  In the third embodiment, the control circuit 26 calculates and sets the scanning speed of the scanner 241 together with the exposure start timing in the processing of step S13 and step S14 in FIG.

[Fourth Embodiment]
In the third embodiment described above, the scanning speed by the scanner 241 is changed. However, the change of the position of the edge PV1a of the image forming area is to make the scanning speed by the scanner 241 constant and to change the conveying speed of the adjustment roller 250. But you can do it. Next, a fourth embodiment of the present invention that controls the conveyance speed of the adjustment roller 250 will be described. In the description of the following embodiments, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 14 is a diagram showing an image forming area on a sheet in the fourth embodiment of the present invention.

  As an example of the paper, part (a) in FIG. 14 shows the paper P220 that is located on the innermost side opposite to the cover side of the booklet, and part (b) shows the paper on the most cover side of the booklet. A sheet P201 to be positioned is shown. Here, images are formed on the paper P220 and the paper P201 in the direction indicated by the arrow Z in the image output device 24.

  In the fourth embodiment, the conveyance speed of the adjustment roller 250 is decreased as the sheet is positioned closer to the cover side of the booklet.

  In the fourth embodiment, the control circuit 26 (see FIG. 4) is configured such that the distance from the center C of the sheet P220 of the edge PV1a near the sheet center of the image forming region PV1 adds a certain margin width m to the prohibited distance. The conveying speed of the adjusting roller 250 is set so that the distance becomes equal. That is, assuming that the direction indicated by the arrow Z in FIG. 14 is the time axis, the transfer speed of the adjustment roller 250 is set to transfer the electrostatic latent image corresponding to the edge PV1a closer to the center of the image forming area PV1 to the sheet. At the time of completion, the sheet is made slower so that the sheet is delayed by the forbidden distance M120. The deceleration speed is obtained by calculation from the peripheral speed of the photosensitive drum 242. By transporting the sheet to the adjustment roller 250 at this low transport speed, the width becomes shorter in the direction from the center of the spread of the image to be formed toward the spread end while keeping the exposure start timing constant. As a result, in the image transferred and fixed on the paper P220, the distance from the center C of the paper P220 of the edge PV1a closer to the center of the image forming area PV1 becomes a distance obtained by adding the margin width m to the prohibited distance M120.

  As described above, the conveyance of the adjustment roller 250 is controlled at the conveyance speed obtained based on the position of the paper in the booklet, thereby controlling the electrostatic latent image formation start timing in the first embodiment. Similarly to the above, the position of the edge near the center of the image forming area can be accurately controlled. In addition, according to the fourth embodiment, as the position of the edge near the center is changed, the width of the image becomes shorter in the direction from the center of the spread toward the spread end, so that the width of the image forming area is closer to the spread end. The position of the edge is constant for all sheets. Further, in the fourth embodiment, since the scanning speed of the scanner 241 is constant, the width of the formed image booklet in the back direction is not shortened. In the fourth embodiment, since the conveying speed of the adjustment roller 250 is changed, the electrostatic latent image formation start timing is taken into consideration for the image forming region PV2 in consideration of the reduced width of the image. Delay. Alternatively, the time for the image forming area PV2 to reach the photosensitive drum is controlled by accelerating and decelerating the paper during the period from the passage of the image forming area PV1 through the photosensitive drum until the image forming area PV2 reaches the photosensitive drum. Then, the exposure start timing of the electrostatic latent image may be adjusted.

  In the fourth embodiment, in steps S13 and S14 of FIG. 11, the control circuit 26 calculates and sets the conveyance speed of the adjustment roller 250 together with the exposure start timing.

  In the above-described embodiment, the control circuit 26 is described as being incorporated in the image forming apparatus 2, but the present invention is not limited to this. For example, the control circuit includes an image forming apparatus and a square fold apparatus. It may be mounted on both and share functions.

  In the above-described embodiment, the prohibition distance is described based on the sheet number information and the sheet thickness information. However, the present invention is not limited to this. For example, the prohibition distance is the sheet number information or It may be obtained based on one of the sheet thickness information.

  Further, in the above-described embodiment, it has been described that two holes are punched in a sheet in which the punch 97 is folded. However, the present invention is not limited to this, and the booklet preparation unit is one or three or more. These holes may be perforated.

1 is a diagram illustrating an image forming system that is an embodiment of a sheet processing apparatus of the present invention. FIG. It is a figure which shows the outline | summary of the image forming apparatus of the image forming system shown in FIG. It is a figure which shows the outline | summary of the function of a square fold apparatus. It is a figure which shows the outline | summary of the function of a punch. FIG. 2 is a block diagram illustrating an electrical configuration of the image forming system illustrated in FIG. 1. It is a figure which shows the state by which the paper was folded. FIG. 7 is a cross-sectional view schematically showing a part of the paper shown in FIG. 6. It is a table | surface which shows the prohibition distance for every paper. It is sectional drawing which shows typically the state by which the paper of thickness different from what is shown in FIG. 7 was folded. It is a figure which shows the image formation area on a paper. 6 is a flowchart illustrating image formation / bookbinding processing in the image forming system. It is a figure which shows the image formation area on the paper in the 2nd Embodiment of this invention. It is a figure which shows the image formation area on the paper in the 3rd Embodiment of this invention. It is a figure which shows the image formation area on the paper in the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming system 2 Image forming apparatus 5 Post-processing apparatus 6 Inserter 7 Booklet finisher 8 Trimmer 9 Square fold apparatus 10 Stacker 24 Image output apparatus 26 Control circuit 97 Punch 241 Scanner 242 Photosensitive drum 250 Adjustment roller 259 Conveyance roller

Claims (8)

An image forming unit that forms images on a plurality of sheets;
A booklet preparation unit for producing a booklet in which a binding hole is formed by punching a hole at a position separated from the back by a predetermined distance, and stacking and folding the plurality of sheets;
In the image forming unit, the edge of the spread facing toward the center of the paper that is to be positioned on the cover side of the booklet by being folded by the booklet preparing unit, in the image forming region that is further away from the center, A sheet processing apparatus comprising: a control unit that forms an image.   The control unit obtains paper number information indicating the number of paper sheets constituting the booklet, and the image forming unit has an edge closer to the center of the spread according to the number of papers indicated by the paper number information from the center. The sheet processing apparatus according to claim 1, wherein an image is formed in the image forming area located at a distance.   The control unit obtains sheet thickness information representing the thickness of the sheet constituting the booklet, and the image forming unit has an edge closer to the center of the spread, the sheet thickness represented by the sheet number information from the center. The sheet processing apparatus according to claim 1, wherein an image is formed in an image forming area located at a distance corresponding to the image forming area. The image forming unit includes a rotating image carrier, and an exposure unit that forms an electrostatic latent image on the surface of the image carrier by scanning the surface of the image carrier with exposure light in the direction of the rotation axis of the image carrier. The electrostatic latent image is developed with toner to obtain a toner image, and the toner image is finally transferred and fixed on a sheet to form an image composed of a fixed toner image on the sheet. Yes,
The control unit obtains an exposure start timing for causing the exposure unit to start forming an electrostatic latent image on the basis of the degree to which the booklet preparation unit positions the paper on the cover side of the booklet. 2. The sheet processing apparatus according to claim 1, wherein formation of an electrostatic latent image is started at the exposure start timing. A paper transport unit that transports the paper along a transport path passing through the image forming unit;
The control unit obtains a conveyance start timing for starting the conveyance of the paper by the paper conveyance unit based on the degree that the booklet production unit positions the paper on the cover side of the booklet, and sends the paper conveyance unit to the paper conveyance unit. 5. The sheet processing apparatus according to claim 4, wherein the sheet is started to be conveyed at the conveyance start timing.   The control unit causes the image forming unit to form an image having a shorter width in the direction from the center of the spread toward the spread end as the sheet is positioned on the cover side of the booklet by being folded by the booklet preparation unit. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is one.   The control unit obtains a scanning speed for causing the exposure unit to scan the surface of the image carrier with exposure light based on the degree that the booklet preparation unit positions the sheet on the cover side of the booklet, and the exposure unit 7. The sheet processing apparatus according to claim 6, wherein an electrostatic latent image is formed by scanning the surface of the image carrier with exposure light at the scanning speed. A paper transport unit that transports the paper along a transport path passing through the image forming unit;
The control unit obtains the conveyance speed of the paper conveyance unit based on the degree that the booklet production unit positions the paper on the cover side of the booklet, and conveys the paper at the conveyance speed. The sheet processing apparatus according to claim 7.

Images