Paper post-processing device and paper post-processing system

Abstract

To achieve bending of a paper bundle without hindrance by appropriately setting a relationship between a travel speed of a tip of a bending blade and a travel speed of a peripheral surface of an individual bending roller.SOLUTION: A saddle stitch part 27 in a sheet post-processing device 20 matches a travel speed of a tip 79C of a bending blade 79 with a travel speed of a peripheral surface of an individual bending roller 78 at the timing when a recording sheet bundle comes into contact with the peripheral surface of the individual bending roller 78, or alternatively, matches the travel speed of the tip 79C of the bending blade 79 with the travel speed of the peripheral surface of the individual bending roller 78 at the timing when the recording sheet bundle reaches a nip area of the individual bending roller 78.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a paper post-processing apparatus and a paper post-processing system for performing processing on a stack of multiple sheets, and particularly to a technique for folding a stack of sheets.

Background Art

[0002] In an image forming apparatus, an image of a document is read by an image reading unit, and the image of the document is formed on a sheet (recording paper) by an image forming unit. Further, in a paper post-processing apparatus, a sheet on which an image of a document is formed is received from the image forming apparatus, and post-processing is performed on the sheet. Examples of the post-processing performed by the paper post-processing apparatus include a folding process of folding a stack of multiple sheets.

[0003] For example, in the folding apparatus described in Patent Document 1, a pair of folding rollers and a folding blade that moves in the contact / separation direction with respect to the nip portion of each folding roller are provided. When a sheet is discharged from a paper discharge roller and conveyed to each folding roller, the folding blade is moved to the nip portion of each folding roller through the sheet, and the sheet is folded by each folding roller. The folding process of the sheet is performed while rotating each folding roller at the same linear speed as the paper discharge linear speed of the paper discharge roller. Further, the moving speed of the folding blade is set slower than the linear speed of each folding roller. Thereby, the folding process can be performed without temporarily stopping or reducing the rotation speed of each folding roller, and the productivity can be improved.

[0004] Furthermore, in the sheet post-processing device described in Patent Document 2, the movement of the pressing plate (corresponding to a folding blade) is started after a predetermined time has elapsed from the moment the leading edge of the paper being transported by the transport roller pair is detected by the paper leading edge detection sensor. The movement speed of the pressing plate is set to be faster than the paper transport speed. In addition, the pressing operation of the paper by the pressing plate is performed such that the portion of the paper downstream from the contact point with the pressing plate in the paper transport direction is pulled back in the opposite direction to the paper transport direction. As a result, the paper can be folded at the target folding position while being transported without the need for a paper stopper. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-168175 [Patent Document 2] Japanese Patent Publication No. 2013-082512 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Incidentally, the folding blade starts moving from a position spaced apart from the nip area of ​​each folding roller and approaches the nip area, causing the speed at which the tip of the folding blade moves to change. Therefore, it is necessary to precisely adjust the speed at which the tip of the folding blade moves.

[0007] The inventors of this invention have clarified that the relationship between the moving speed of the tip of the folding blade and the moving speed of the circumferential surface of each folding roller differs between paper stacks on which images are recorded by an inkjet method and paper stacks on which images are recorded by an electrophotographic method, in order for the paper stack to be folded without hindrance. For example, in the case of an inkjet method, if there is a difference between the moving speed of the tip of the folding blade and the moving speed of the circumferential surface of each folding roller at the timing when the recording paper comes into contact with the circumferential surface of each folding roller, the ink from the recording paper will transfer to the circumferential surface of each folding roller. Therefore, it is desirable to match their moving speeds at the aforementioned timing. On the other hand, it was found that in the case of an electrophotographic method, it is not necessarily required to match their moving speeds at the aforementioned timing.

[0008] In the above-mentioned Patent Document 1, the movement speed of the folding blade is set to be slower than the linear speed of each folding roller, but as mentioned above, it does not mention that the relationship between the movement speed of the tip of the folding blade, which allows for smooth folding of the paper stack, and the movement speed of the circumferential surface of each folding roller differs between the inkjet method and the electrophotographic method.

[0009] Furthermore, while Patent Document 2 sets the movement speed of the push plate to be faster than the paper transport speed, it still does not mention the relationship described above.

[0010] This invention has been made in view of the above circumstances, and aims to enable the folding of a stack of paper without hindrance by appropriately setting the relationship between the moving speed of the tip of the folding blade and the moving speed of the circumferential surface of each folding roller. [Means for solving the problem]

[0011] A paper post-processing device according to one aspect of the present invention is a paper post-processing device that processes paper received from an image forming device that forms an image of an original on paper, comprising: a pair of folding rollers that are pressed against each other and rotated in opposite directions; a blade that is supported to be movable in the direction of approaching and separating from a nip area formed between each folding roller; a transport unit that transports a stack of paper between the nip area of ​​each folding roller and the blade; a drive unit that moves the blade in the direction of approaching and separating from the nip area of ​​each folding roller, and pushes the stack of paper into the nip area of ​​each folding roller with the blade to fold it; and The image forming apparatus comprises a drive control unit that controls a drive unit to adjust the speed at which the tip of the blade moved by the drive unit, wherein, when the image forming apparatus is of the inkjet type, the drive control unit controls the drive unit to match the speed at which the tip of the blade moves to the speed at which the circumferential surface of the folding rollers moves when the paper comes into contact with the circumferential surface of each folding roller, and when the image forming apparatus is of the electrophotographic type, the drive unit controls the drive unit to match the speed at which the tip of the blade moves to the speed at which the circumferential surface of the folding rollers moves when the stack of paper reaches the nip area of ​​each folding roller.

[0012] Furthermore, a post-processing system for paper according to one aspect of the present invention comprises an image forming apparatus that forms an image of an original on paper using ink by an inkjet method, and a post-processing apparatus that receives the paper from the image forming apparatus and processes the paper, wherein the post-processing apparatus comprises a pair of folding rollers that are pressed against each other and rotated in opposite directions, a blade that is supported to be movable in the direction of contact with and away from a nip area formed between each folding roller, a transport unit that transports paper between the nip area of ​​each folding roller and the blade, a drive unit that moves the blade in the direction of contact with and away from the nip area of ​​each folding roller, and pushes the bundle of paper into the nip area of ​​each folding roller with the blade to fold it, and a drive control unit that drives and controls the drive unit, wherein the drive control unit drives and controls the drive unit so that the moving speed of the tip of the blade matches the moving speed of the circumferential surface of the folding roller at the timing when the bundle of paper contacts the circumferential surface of each folding roller.

[0013] Furthermore, a post-processing system for paper according to one aspect of the present invention comprises an image forming apparatus that forms an image of an original on paper using a developer containing toner and wax by an electrophotographic method, and a post-processing apparatus that receives the paper from the image forming apparatus and processes the paper, wherein the post-processing apparatus comprises a pair of folding rollers that are pressed against each other and rotated in opposite directions, a blade that is supported to be movable in the direction of approach to and away from a nip area formed between each folding roller, a transport unit that transports paper between the nip area of ​​each folding roller and the blade, a drive unit that moves the blade in the direction of approach to and away from the nip area of ​​each folding roller, and pushes the bundle of paper into the nip area of ​​each folding roller with the blade to fold it, and a drive control unit that drives and controls the drive unit, wherein the drive control unit drives and controls the drive unit so that the moving speed of the tip of the blade matches the moving speed of the circumferential surface of the folding roller at the timing when the bundle of paper reaches the nip area of ​​each folding roller.

[0014] Furthermore, a paper post-processing device according to one aspect of the present invention comprises: a pair of folding rollers pressed against each other and rotated in opposite directions; a blade supported to move in the direction of contact with and away from a nip area formed between each folding roller; a transport unit for transporting a stack of paper between the nip areas of each folding roller and the blade; a drive unit for moving the blade in the direction of contact with and away from the nip areas of each folding roller, thereby pressing the stack of paper into the nip areas of each folding roller and causing it to fold; and a drive control unit for driving and controlling the drive unit, wherein the drive control unit drives and controls the drive unit so that the moving speed of the tip of the blade matches the moving speed of the circumferential surface of the folding roller at the timing when the stack of paper comes into contact with the circumferential surface of each folding roller.

[0015] Furthermore, a paper post-processing device according to one aspect of the present invention comprises: a pair of folding rollers pressed against each other and rotated in opposite directions; a blade supported to be movable in the direction of approaching and separating from a nip area formed between each folding roller; a transport unit for transporting a stack of paper between the nip area of ​​each folding roller and the blade; a drive unit for moving the blade in the direction of approaching and separating from the nip area of ​​each folding roller, causing the stack of paper to be folded by being pressed into the nip area of ​​each folding roller by the blade; and a drive control unit for driving and controlling the drive unit, wherein the drive control unit drives and controls the drive unit so that the moving speed of the tip of the blade matches the moving speed of the circumferential surface of the folding roller at the timing when the stack of paper reaches the nip area of ​​each folding roller. [Effects of the Invention]

[0016] According to the present invention, the relationship between the moving speed of the tip of the folding blade and the moving speed of the circumferential surface of each folding roller can be accurately set so that the folding of the stack of paper can be performed without any problems. [Brief explanation of the drawing]

[0017] [Figure 1]It is a cross-sectional view showing an image forming apparatus and a paper post-processing apparatus in a paper post-processing system according to the first embodiment of the present invention. [Figure 2] It is a functional block diagram showing the main internal configurations of the image forming apparatus and the paper post-processing apparatus. [Figure 3] It is a cross-sectional view showing an enlarged view of the saddle stitching part in the paper post-processing apparatus. [Figure 4] It is a cross-sectional view showing an enlarged view of each divided tray, each folding roller, a folding blade, a rotating cam, etc. in the saddle stitching part. [Figure 5] (A) and (B) are diagrams showing the movement of the folding blade accompanying the rotation of the rotating cam in the saddle stitching part. [Figure 6] (A) and (B) are diagrams showing the movement of the folding blade accompanying the rotation of the rotating cam following FIGS. 5(A) and (B). [Figure 7] It is a diagram showing a state where a stack of recording papers pushed up by the folding blade contacts the peripheral surface of each folding roller. [Figure 8] It is a cross-sectional view showing an image forming apparatus and a paper post-processing apparatus in a paper post-processing system according to the second embodiment of the present invention.

Mode for Carrying Out the Invention

[0018] Hereinafter, an embodiment of a paper post-processing apparatus and a paper post-processing system according to the present invention will be described with reference to the drawings. <First Embodiment> FIG. 1 is a cross-sectional view showing an image forming apparatus and a paper post-processing apparatus in a paper post-processing system according to the first embodiment of the present invention. The paper post-processing system Sy according to the first embodiment includes an image forming apparatus 10 that reads an image of a document and forms it on a recording paper, and a paper post-processing apparatus 20 that receives the recording paper from the image forming apparatus 10 and performs post-processing on the recording paper.

[0019] The image forming apparatus 10 comprises an image reading unit 11 and an image forming unit 12. When multiple documents M are placed on the document tray 1, the image reading unit 11 sequentially pulls these documents M out of the document tray 1 and transports them, while reading the image of each document M with an image sensor, and sequentially discharges each document M into the output tray 2 and stacks them. For each image of each document M, the analog output of the image sensor is converted into a digital signal to generate image data representing the image of the document M.

[0020] The image forming unit 12, each time it receives sequential input of image data representing multiple originals M, forms an image of the originals M represented by the image data onto the recording paper P using an inkjet method. The image forming unit 12 has line heads (examples of ink heads) 15 that eject ink droplets of four colors (black, cyan, magenta, and yellow). Each line head 15 ejects ink droplets of its respective color onto the recording paper P that has been transported from the paper feeding unit 14 through the first transport path 3 to the transport unit 4, thereby forming a color image on the recording paper P.

[0021] The conveying unit 4 comprises a drive roller 8, a driven roller 9, a tension roller 5, and a conveying belt 6. The conveying belt 6 is an endless belt and is stretched between the drive roller 8, the driven roller 9, and the tension roller 5. The drive roller 8 is a roller that is driven to rotate counterclockwise by a motor (not shown). When the drive roller 8 is driven to rotate, the conveying belt 6 moves in a counterclockwise orbit, and the driven roller 9 and the tension roller 5 rotate in a counterclockwise direction as well.

[0022] The tension roller 5 is a roller that maintains the appropriate tension of the conveyor belt 6. The suction roller 7 is in contact with the conveyor belt 6 and electrostatically attracts the recording paper P fed from the paper feeding unit 14 to the conveyor belt 6 by charging the conveyor belt 6.

[0023] The image forming unit 12 forms an image of each original document M on its respective recording paper P, and each recording paper P is transported via the relay transport path 18 and through the transport roller 19 to the paper post-processing device 20.

[0024] Furthermore, when recording the image of the original document M on the back side of the recording paper P, the recording paper P is transported from the relay transport path 18 to the transport roller 16, the transport roller 16 is temporarily stopped and rotated in reverse in a switchback transport operation, the recording paper P is returned to the transport unit 4 via the second transport path 17, the front and back sides of the recording paper P are reversed, the image forming unit 12 forms the image of the original document M on the back side of the recording paper P, and the recording paper P is transported via the relay transport path 18 and the transport roller 19 to the paper post-processing device 20.

[0025] On the other hand, the paper post-processing device 20 includes a plurality of transport rollers 21, 22, and 23 for transporting the recording paper P from the image forming apparatus 10, a branching claw 24 that guides the recording paper P that has passed through the transport roller 21 horizontally to the transport roller 22 or guides the recording paper P that has passed through the transport roller 21 downward to the transport roller 23, a single-sided binding unit 25 that stacks a plurality of recording paper P and staples one end of the recording paper bundle made up of each recording paper P, an output tray 26 from which the recording paper bundle that has been stapled by the single-sided binding unit 25 is discharged, a saddle-stitching unit 27 that stacks each recording paper P and staples the center of the recording paper bundle made up of each recording paper P and folds the recording paper bundle in the middle, and an output tray 28 from which the recording paper bundle that has been stapled and folded by the saddle-stitching unit 27 is discharged.

[0026] The single-sided binding unit 25 includes a processing tray 71 into which multiple recording papers P transported by each of the transport rollers 21 and 22 are successively discharged, a paddle 73 that biases and moves the recording papers P toward the stapling unit 72 each time a recording paper P is discharged into the processing tray 71, a stapling unit 72 that applies stapling to one end of a stack of recording papers P piled on the processing tray 71, and a discharge roller 74 that discharges the stack of recording papers that has been stapled by the stapling unit 72 into the discharge tray 26.

[0027] The saddle-stitching unit 27 includes two divided trays 75A, 75B from which multiple recording papers P transported by each transport roller 21, 23 (an example of a transport unit in the claims) are sequentially discharged, a pair of stoppers 85A, 85B that move the recording papers P or stacks of recording papers P on each divided tray 75A, 75B to adjust the position of the recording papers P or stacks of recording papers P, each rotating belt 76A, 76B that supports each stopper 85A, 85B and moves each stopper 85A, 85B in the transport direction of the recording papers P, and a stapling process applied to the center of the stacks of recording papers on each divided tray 75A, 75B. The device includes a tapered section 77, folding rollers 78 positioned above the space between each divided tray 75A, 75B and pressed against each other, folding blades 79 positioned opposite the nip area of ​​each folding roller 78 through the space between each divided tray 75A, 75B, a rotating cam 80 that moves the folding blades 79 in a direction toward and away from the nip area of ​​each folding roller 78, a guide section 81 positioned downstream in the direction of transport of the recording paper stack by each folding roller 78 to guide the recording paper stack, a transport roller 82 that transports the recording paper stack, and a discharge conveyor 83 that discharges the recording paper stack to the discharge tray 28.

[0028] Next, the configuration related to the control of the image forming apparatus 10 and the paper post-processing device 20 will be described. Figure 2 is a functional block diagram showing the main internal configuration of the image forming apparatus 10 and the paper post-processing device 20. As shown in Figure 2, the image forming apparatus 10 includes an image reading unit 11, an image forming unit 12, a display unit 41, an operation unit 42, a touch panel 43, a storage unit 44, a control unit 46, and an interface 47. These components are capable of sending and receiving data or signals to and from each other via a bus.

[0029] The display unit 41 consists of a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display, among others.

[0030] The control unit 42 is equipped with physical keys such as a numeric keypad, an enter key, and a start key.

[0031] A touch panel 43 is positioned on the screen of the display unit 41. The touch panel 43 is a so-called resistive or capacitive touch panel, which detects contact (touch) of the user's finger or other object with the touch panel 43, along with the contact position, and outputs a detection signal indicating the coordinates of the contact position to the control unit 46 or the like.

[0032] The memory unit 44 is a large-capacity storage device such as an SSD (Solid State Drive) or HDD (Hard Disk Drive) that stores various application programs and various types of data.

[0033] The control unit 46 is connected to the image reading unit 11, image forming unit 12, display unit 41, operation unit 42, touch panel 43, storage unit 44, and interface 47, and controls the operation of these components and transmits and receives signals or data between them. In other words, the control unit 46 performs the control and processing necessary for the operation of the image forming apparatus 10.

[0034] The control unit 46 consists of a processor, RAM (Random Access Memory), and ROM (Read Only Memory). The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit), and executes the above-mentioned controls and processes necessary for the operation of the image forming apparatus 10 according to the control program stored in the ROM or storage unit 44.

[0035] Furthermore, the control unit 46 has the function of controlling the display operation of the display unit 41. In addition, the control unit 46 receives operation instructions input by the user based on detection signals output from the touch panel 43 or operations on the physical keys of the operation unit 42. For example, the control unit 46 receives touch operations on the GUI (Graphical User Interface) displayed on the screen of the display unit 41 via the touch panel 43.

[0036] Furthermore, the paper post-processing device 20 includes a single-sided binding unit 25, a saddle-stitching unit 27, a drive control unit 56, and an interface 57. These components are capable of sending and receiving data or signals to and from each other via a bus.

[0037] The drive control unit 56 consists of a processor, RAM, and ROM, and controls the drive of the single-sided binding unit 25 and the saddle-stitching unit 27.

[0038] The control unit 46 of the image forming apparatus 10 and the drive control unit 56 of the paper post-processing device 20 input and output data or signals to each other through their respective interfaces 47, 57. For example, the control unit 46 of the image forming apparatus 10 outputs a control signal indicating post-processing by the paper post-processing device 20 to the drive control unit 56 of the paper post-processing device 20, and the drive control unit 56 of the paper post-processing device 20 drives the single-sided binding unit 25 or the saddle-stitching unit 27 according to that control signal. In a post-processing system Sy with such a configuration, for example, when the image forming apparatus 10 reads images from multiple originals M and records them on separate sheets of recording paper, and the saddle-stitching unit 27 of the post-processing device 20 saddle-stitches the center of the stack of recording papers and folds the stack in the middle, the user operates the GUI displayed on the screen of the display unit 41 via the touch panel 43 to input an instruction to execute the saddle-stitching process. The user then sets the multiple originals M into the image reading unit 11 and inputs a copy instruction by operating the start key on the operation unit 42.

[0039] The control unit 46 of the image forming apparatus 10 outputs a control signal indicating saddle stitching to the paper post-processing device 20 via the interface 47. Simultaneously, it causes the image reading unit 11 to sequentially read the image of each original document M, the image forming unit 12 to form the image of each original document M on the respective recording paper, and these recording papers to be transported sequentially to the paper post-processing device 20.

[0040] The drive control unit 56 of the paper post-processing device 20 receives a control signal indicating saddle stitching through the interface 57, and sequentially receives each sheet of recording paper transported from the image forming apparatus 10. Based on this control signal, it drives and controls the motors that serve as the drive sources for each rotating belt 76A, 76B, each folding roller 78, rotating cam 80, transport roller 82, and discharge conveyor 83 in the saddle stitching unit 27, thereby operating them. As a result, the center of the stack of recording paper is stapled, the stack of recording paper is folded in the middle, and the stack of recording paper is discharged into the discharge tray 28.

[0041] Figure 3 is an enlarged cross-sectional view showing the saddle-stitching section 27 in the paper post-processing device 20. As shown in Figure 3, in the saddle-stitching section 27, the two divided trays 75A and 75B are arranged side by side in the direction of paper transport by the transport rollers 23, with a space between them.

[0042] Multiple sheets of recording paper are sequentially transported by the transport rollers 23 and stacked on each of the divided trays 75A and 75B. Each time a sheet of recording paper is stacked on each of the divided trays 75A and 75B, the drive control unit 56 rotates and moves each of the rotating belts 76A and 76B according to the size of the recording paper in the transport direction, bringing both ends of the recording paper into contact with their respective stoppers 85A and 85B to align them, and stacking each sheet of recording paper on each of the divided trays 75A and 75B to form a stack of recording paper.

[0043] The drive control unit 56 rotates each of the rotating belts 76A and 76B to move the stacks of recording paper on each of the divided trays 75A and 75B using the stoppers 85A and 85B, positioning the center of the stacks of recording paper to the stapling position of the stapling unit 77, and causing the stapling unit 77 to perform stapling on the center of the stacks of recording paper.

[0044] Next, the drive control unit 56 rotates each of the rotating belts 76A and 76B to move the stacks of recording paper on each of the divided trays 75A and 75B using the stoppers 85A and 85B, and positions the center of the stacks of recording paper in the space between each of the divided trays 75A and 75B.

[0045] The drive control unit 56 rotates each folding roller 78 in different arrow directions, causing the rotating cam 80 to move the folding blade 79 toward and toward the nip area formed between each folding roller 78. When the folding blade 79 moves toward the nip area of ​​each folding roller 78 via the stack of recording paper, the tip of the folding blade 79 pushes up the center of the stack of recording paper, pushing the center of the stack into the nip area of ​​each folding roller 78, causing the center of the stack to be folded by each folding roller 78, and the stack of recording paper to be folded in half. The folded stack of recording paper passes through each folding roller 78 and is guided by the guide unit 81 to the transport roller 82, which transports it to the discharge conveyor 83, and it is discharged to the discharge tray 28 via the discharge conveyor 83.

[0046] Figure 4 is an enlarged cross-sectional view showing the individual divider trays 75A and 75B, the folding rollers 78, the folding blade 79, the rotating cam 80, etc., in the saddle-stitching section 27. As shown in Figure 4, the folding blade 79 has an L-shaped cross-section consisting of a vertical plate 79A and a bottom plate 79B, and is supported to move freely in the direction of the arrow D, approaching and moving away from the nip area NP of each folding roller 78. In addition, a contact roller 86 is rotatably supported near the lower end of the vertical plate 79A of the folding blade 79.

[0047] The rotating cam 80 is supported by the rotating shaft 88 and rotates together with the rotating shaft 88. In its extended state, the coil spring 87 has both ends locked to the bottom plate 79B of the folding blade 79 and the fixed position 27A of the saddle stitching section 27 (for example, the frame of the saddle stitching section 27), biasing the folding blade 79 in a direction that moves it away from the nip area NP of each folding roller 78. The rotating cam 80 has a shape in which the radius from the center of rotation to the circumferential surface differs depending on the position of the circumferential surface.

[0048] The contact rollers 86 of the folding blade 79 move together with the folding blade 79 in the direction of the arrow D. The rotation center of the rotating shaft 88 and the rotating cam 80 are positioned at a location that intersects with the movement trajectory of the contact rollers 86 in the direction of the arrow D. Since the folding blade 79 is biased by the coil spring 87 to move away from the nip area NP of each folding roller 78, the contact rollers 86 of the folding blade 79 are always pressed against the circumferential surface of the rotating cam 80.

[0049] Due to the biasing force of the coil spring 87, the contact roller 86 of the folding blade 79 is always pressed against the circumferential surface of the rotating cam 80. Therefore, when the rotating cam 80 (rotating shaft 88) rotates, the contact roller 86 of the folding blade 79 follows the circumferential surface of the rotating cam 80 and moves in the direction of the arrow D, and the tip 79C of the folding blade 79 also moves in the direction of the arrow D.

[0050] Furthermore, the rotating cam 80, contact roller 86, coil spring 87, rotating shaft 88, and motor 801 (Figure 2) that rotates the rotating shaft 88 and the rotating cam 80 are examples of a drive unit described in the claims that moves the folding blade 79 in the direction of the arrow D.

[0051] As shown in Figure 5(A), the rotating cam 80 has a circumferential surface portion 80A closest to the rotation center R0 of the rotating cam 80 (rotation axis 88), a circumferential surface portion 80C furthest from the rotation center R0 of the rotating cam 80, and two circumferential surface portions 80B of the rotating cam 80 located between circumferential surface portions 80A and 80C. When the contact roller 86 of the folding blade 79 is in contact with the circumferential surface portion 80A of the rotating cam 80, the contact roller 86 of the folding blade 79 is furthest away from the nip area NP of each folding roller 78, and the tip 79C of the folding blade 79 is also furthest away from the nip area NP and retracts from the space between the divided trays 75A and 75B. In this state, the recording paper stack PT is moved on each divided tray 75A and 75B, and the central part of the recording paper stack PT reaches the space between the divided trays 75A and 75B and is positioned.

[0052] As shown in Figure 5(B), when the rotating cam 80 (rotating shaft 88) rotates in the direction of the arrow, the contact roller 86 of the folding blade 79 contacts one circumferential portion 80B of the rotating cam 80 and moves in a direction approaching the nip area NP, and the tip 79C of the folding blade 79 also moves in a direction approaching the nip area NP, pushing up the central part of the recording paper stack PT. This initiates the folding of the central part of the recording paper stack PT.

[0053] Then, as shown in Figure 6(A), when the rotating cam 80 (rotating shaft 88) rotates 180 degrees and the contact roller 86 of the folding blade 79 is in contact with the circumferential portion 80C, the contact roller 86 of the folding blade 79 comes closest to the nip area NP of each folding roller 78, and the tip 79C of the folding blade 79 also comes closest to the nip area NP. As a result, the central part of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 and folded.

[0054] Furthermore, as shown in Figure 6(B), when the rotating cam 80 (rotating shaft 88) rotates, the contact roller 86 of the folding blade 79 contacts the other circumferential portion 80B of the rotating cam 80 and moves away from the nip area NP, and the tip 79C of the folding blade 79 also moves away from the nip area NP and retracts from the space between the divided trays 75A and 75B. The folded recording paper bundle PT passes through the nip area NP of each folding roller 78 and is conveyed to the guide section 81.

[0055] As the rotating cam 80 moves the tip 79C of the folding blade 79 toward the nip area NP, the tip 79C of the folding blade 79 pushes the central part of the recording paper stack PT into the nip area NP of each folding roller 78, and the recording paper stack PT is folded by each folding roller 78.

[0056] Here, the image forming unit 12 in the image forming apparatus 10 forms an image of the original on the recording paper using ink by an inkjet method. Therefore, the stack of recording paper may be folded by the saddle stitching unit 27 of the paper post-processing device 20 before the ink adhering to the surface of the recording paper dries. For this reason, in the saddle stitching unit 27, as shown in Figure 7, before the center of the stack of recording paper PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79, if the surface of the recording paper in the stack of recording paper PT is rubbed against the circumferential surface of each folding roller 78 at the timing when the stack of recording paper PT comes into contact with the circumferential surface of each folding roller 78, the ink adhering to the surface of the recording paper may transfer to the circumferential surface of each folding roller 78, staining the circumferential surface of each folding roller 78 with ink. This can cause a problem where the ink from the circumferential surface of each folding roller 78 transfers to the recording paper of another stack of recording paper, resulting in the recording paper becoming dirty.

[0057] The inventors of the present invention have clarified that the cause of the above-mentioned problem, which occurs when the surface of the recording paper is rubbed against the circumferential surface of each folding roller 78, lies in the difference between the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78. For example, if, at the moment when the stack of recording paper PT comes into contact with the circumferential surface of each folding roller 78, the moving speed of the stack of recording paper PT, which is pushed up by the tip 79C of the folding blade 79, becomes slower than the moving speed of the circumferential surface of each folding roller 78. As a result, the surface of the recording paper is rubbed against the circumferential surface of each folding roller 78, and the ink adhering to the surface of the recording paper is transferred to the circumferential surface of each folding roller 78.

[0058] Therefore, in the first embodiment, before the central part of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79, the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78 are matched at the timing when the recording paper stack PT comes into contact with the circumferential surface of each folding roller 78. As a result, the surface of the recording paper follows and contacts the circumferential surface of each folding roller 78, and the central part of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79, and the central part of the recording paper stack PT is folded, without the surface of the recording paper PT rubbing against the circumferential surface of each folding roller 78, or at least without causing the above-mentioned problems caused by rubbing.

[0059] The position and movement speed of the tip 79C of the folding blade 79 are determined according to the radius from the rotation center of the rotating cam 80 (rotating shaft 88) to the circumferential surface, the rate of change of said radius, and the rotation speed of the rotating cam 80.

[0060] For example, through experiments, the position of the tip 79C of the folding blade 79 when it is furthest from the nip area NP (referred to as the distance position), as shown in Figure 5(A), the position of the tip 79C of the folding blade 79 when the recording paper stack PT is in contact with the circumferential surface of each folding roller 78 (referred to as the contact position), as shown in Figure 7, and the position of the tip 79C of the folding blade 79 when the central part of the recording paper stack PT is pushed into the nip area NP of each folding roller 78 (referred to as the push-in position), are set, respectively, and the radius from the rotation center of the rotating cam 80 to the circumferential surface and the rate of change of said radius are set so that the tip 79C of the folding blade 79 reaches the push-in position via the contact position from the distance position, and the moving speed of the tip 79C of the folding blade 79 increases until it reaches the contact position from the distance position, and then the moving speed of the tip 79C of the folding blade 79 is kept approximately constant until it reaches the push-in position from the contact position.

[0061] Furthermore, in order to match the moving speed of the tip 79C of the folding blade 79 with the moving speed of the circumferential surface of each folding roller 78, the faster the rotation speed of each folding roller 78, the faster the rotation speed of the rotating cam 80 must be increased, and the slower the rotation speed of each folding roller 78, the slower the rotation speed of the rotating cam 80 must be decreased. The rotation speed of each folding roller 78 is set by adjusting the rotation speed of the motor that rotates each folding roller 78, and similarly, the rotation speed of the rotating cam 80 is set by adjusting the rotation speed of the motor that rotates the rotating cam 80.

[0062] The drive control unit 56 drives and controls the motors that rotate each folding roller 78 and the rotating cam 80, adjusting the rotation speed of the rotating cam 80 according to the rotation speed of the motor for each folding roller 78, so that the moving speed of the tip 79C of the folding blade 79 matches the moving speed of the circumferential surface of each folding roller 78 at the moment when the recording paper stack PT contacts the circumferential surface of each folding roller 78. For example, as shown in Figure 7, if the position of the circumferential surface of the rotating cam 80 that the contact roller 86 contacts at the moment when the recording paper stack PT contacts the circumferential surface of each folding roller 78 is determined in advance, the rotation speed of the rotating cam 80 to match the moving speed of the tip 79C of the folding blade 79 matches the moving speed of the circumferential surface of each folding roller 78 can be calculated based on the radius from the rotation center of the rotating cam 80 to the position of its circumferential surface and the rate of change of that radius.

[0063] As a result, as shown in Figure 7, when the recording paper stack PT comes into contact with the circumferential surface of each folding roller 78, the surface of the recording paper follows the circumferential surface of each folding roller 78 and makes contact without the surface of the recording paper being rubbed against the circumferential surface of each folding roller 78. As shown in Figure 6(A), the tip 79C of the folding blade 79 pushes the central part of the recording paper stack PT into the nip area NP of each folding roller 78, and the central part of the recording paper stack PT is folded.

[0064] Furthermore, the radius from the rotation center of the rotating cam 80 to its circumferential surface and the rate of change of said radius are set so that the movement speed of the tip 79C of the folding blade 79 is kept substantially constant until the tip 79C of the folding blade 79 reaches the pushing position from the contact position. Therefore, even after the recording paper stack PT has come into contact with the circumferential surface of each folding roller 78, the surface of the recording paper will not be rubbed against the circumferential surface of each folding roller 78 until the recording paper stack PT is pushed into the nip area of ​​each folding roller 78. <Second Embodiment> Figure 8 is a cross-sectional view showing an image forming apparatus and a paper post-processing apparatus in a second embodiment of the present invention. In Figure 8, parts that perform the same function as in Figure 1 are denoted by the same reference numerals.

[0065] The paper post-processing system Sy of the second embodiment includes an image forming apparatus 10 that reads an image from a document and forms it on recording paper, and a paper post-processing apparatus 20 that receives the recording paper from the image forming apparatus 10 and performs post-processing on the recording paper.

[0066] The image forming apparatus 10 comprises an image reading unit 11 and an image forming unit 12A. The image reading unit 11 sequentially pulls out and transports multiple documents M from the document tray 1, reads the image of each document M using an image sensor, and sequentially discharges each document M into the output tray 2 and stacks them. For each image of each document M, the analog output of the image sensor is converted into a digital signal to generate image data representing the image of the document M.

[0067] The image forming unit 12A, each time it receives sequential input of image data representing images of multiple originals M, forms an image of the originals M represented by the image data on recording paper P using an electrophotographic method with a developer containing toner. The image forming unit 12A includes an image forming unit 63M for magenta, an image forming unit 63C for cyan, an image forming unit 63Y for yellow, and an image forming unit 63Bk for black. In each of the image forming units 63M, 63C, 63Y, and 63Bk, the surface of the photoreceptor drum 64 is uniformly charged, the surface of the photoreceptor drum 64 is exposed to light to form an electrostatic latent image on the surface of the photoreceptor drum 64, the electrostatic latent image on the surface of the photoreceptor drum 64 is developed into a toner image, and the toner image on the surface of the photoreceptor drum 64 is transferred to the intermediate transfer belt 62. As a result, a color toner image is formed on the intermediate transfer belt 62. This color toner image is secondarily transferred to the recording paper P that has been transported from the paper feeding unit 14 through the first transport path 68 in the nip region N between the intermediate transfer belt 62 and the secondary transfer roller 66.

[0068] After the image forming unit 12A forms an image on each original document M onto its respective recording paper P, each recording paper P is sequentially heated and pressurized in the fixing unit 65, and the respective toner images on each recording paper P are fixed by thermal compression. Furthermore, each recording paper P is transported to the paper post-processing device 20 via the transport roller 61.

[0069] Furthermore, when recording the image of the original document M on the back side of the recording paper P, the recording paper P is transported to the discharge roller 67 in front of the discharge tray 69, the discharge roller 67 is stopped briefly and then rotated in reverse in a switchback transport operation, the recording paper P is returned to the nip section N of the first transport path 68 via the transport roller 61 and the second transport path 70, the front and back sides of the recording paper P are reversed, the image forming unit 12A forms the image of the original document M on the back side of the recording paper P, and the recording paper P is transported to the paper post-processing device 20 via the transport roller 61.

[0070] On the other hand, the configuration of the paper post-processing device 20 is as described with reference to Figure 1 in the first embodiment, and it sequentially receives each recording paper P that has been transported from the image forming apparatus 10, and for example, the saddle-stitching unit 27 staples the center of the recording paper stack made up of each recording paper, folds the recording paper stack in the middle, and discharges the recording paper stack to the discharge tray 28.

[0071] Next, the configuration for controlling the image forming apparatus 10 and the paper post-processing device 20 in the second embodiment is generally the same as that of the first embodiment shown in Figure 2. However, the image forming apparatus 10 in the second embodiment differs from the first embodiment in that it uses an electrophotographic image forming unit 12A instead of an inkjet-type image forming unit 12. The control unit 46 of the image forming apparatus 10 in the second embodiment controls the electrophotographic image forming unit 12A to form an image of the original document M on the recording paper P using the image forming unit 12A in the procedure described above.

[0072] Furthermore, in the second embodiment, the control unit 46 of the image forming apparatus 10 is connected to the image reading unit 11, the image forming unit 12A, the display unit 41, the operation unit 42, the touch panel 43, the storage unit 44, and the interface 47, similar to the first embodiment, and controls the operation of these components and transmits and receives signals or data between them.

[0073] In the second embodiment, the control unit 46 of the image forming apparatus 10 and the drive control unit 56 of the paper post-processing device 20 transmit and receive data or signals to and from each other through their respective interfaces 47, 57. The control unit 46 of the image forming apparatus 10 outputs a control signal indicating post-processing by the paper post-processing device 20 to the drive control unit 56 of the paper post-processing device 20, and the drive control unit 56 of the paper post-processing device 20 drives the single-sided binding unit 25 or the saddle-stitching unit 27 according to the control signal.

[0074] Here, the image forming unit 12A is formed on the recording paper using an electrophotographic method with a developer containing toner. This toner does not wet the surface of the recording paper like ink, and the surface of the recording paper remains dry. In addition, since wax is mixed into this developer, the wax adheres to the surface of the recording paper along with the toner, smoothing the surface of the recording paper P and reducing the friction of the recording paper surface.

[0075] Therefore, as shown in Figure 7, in the saddle-stitch section 27, before the central part of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79, even if the surface of the recording paper in the recording paper stack PT is rubbed against the surface of each folding roller 78 at the timing when the recording paper stack PT comes into contact with the surface of each folding roller 78, the toner adhering to the surface of the recording paper does not transfer to the surface of each folding roller 78, and the surface of each folding roller 78 is not soiled with toner, or only slightly.

[0076] However, because the friction between the recording sheets in the recording sheet stack PT is low, if there is a difference between the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78, the recording sheets in the recording sheet stack PT may shift or tear when the central part of the recording sheet stack PT is folded at the nip area NP of each folding roller 78. For example, if the moving speed of the tip 79C of the folding blade 79 is slower than the moving speed of the circumferential surface of each folding roller 78 at the moment the central part of the recording sheet stack PT reaches the nip area NP of each folding roller 78, the moving speed of the recording sheet stack PT being pushed up by the tip 79C of the folding blade 79 will be slower than the moving speed of the circumferential surface of each folding roller 78. As a result, only the top layer of recording sheet in the recording sheet stack PT will be pulled up at the nip area NP of each folding roller 78, separating this recording sheet from the lower layers of recording sheet, causing the stapled central part of any of the recording sheets to shift or tear.

[0077] Therefore, in this embodiment, at the moment when the tip 79C of the folding blade 79 presses the central part of the recording paper stack PT into the nip area NP of each folding roller 78, the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78 are matched. As a result, the central part of the recording paper stack PT is folded without causing the recording paper in the recording paper stack PT to shift or tear.

[0078] For example, through experiments, the position of the tip 79C of the folding blade 79 that is furthest from the nip area NP (separated position), as shown in Figure 5(A), and the position of the tip 79C of the folding blade 79 when the central part of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 (pressed position), as shown in Figure 6(A), are set, and an intermediate position between the separated position and the pressed position is appropriately set. The radius from the rotation center of the rotating cam 80 to the circumferential surface and the rate of change of said radius are set so that the tip 79C of the folding blade 79 reaches the pressed position via the intermediate position from the separated position, and the movement speed of the tip 79C of the folding blade 79 increases until it reaches the intermediate position from the separated position, and then the movement speed of the tip 79C of the folding blade 79 is kept approximately constant until it reaches the pressed position from the intermediate position.

[0079] Furthermore, the drive control unit 56 drives and controls the motors that rotate each folding roller 78 and the rotating cam 80, adjusting the rotation speed of the rotating cam 80 according to the rotation speed of the motor for each folding roller 78, so that the moving speed of the tip 79C of the folding blade 79 matches the moving speed of the circumferential surface of each folding roller 78 at the moment when the center of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79. For example, if the position of the circumferential surface of the rotating cam 80 that the contact roller 86 contacts at the moment when the center of the recording paper stack PT is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79 is determined in advance, the rotation speed of the rotating cam 80 to match the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78 can be calculated based on the radius from the rotation center of the rotating cam 80 to the position of its circumferential surface and the rate of change of that radius.

[0080] As a result, as shown in Figure 6(A), the tip 79C of the folding blade 79 pushes the central part of the recording paper stack PT into the nip area NP of each folding roller 78, and when the central part of the recording paper stack PT is folded, the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78 are matched, so that only the top layer of recording paper in the recording paper stack PT is lifted up in the nip area NP of each folding roller 78 and not pulled away from the lower layers of recording paper, and the stapled central part of any of the recording papers does not shift or tear.

[0081] Furthermore, the radius from the rotation center of the rotating cam 80 to its circumferential surface and the rate of change of said radius are set so that the movement speed of the tip 79C of the folding blade 79 is kept approximately constant until the tip 79C of the folding blade 79 reaches the push-in position from the intermediate position. This more effectively prevents the central part of the recording paper in the recording paper stack PT from shifting or tearing. <Third Embodiment> In the third embodiment, assuming that the paper post-processing device 20 is applicable to both inkjet and electrophotographic image forming apparatus 10, the rotation speed of the rotating cam 80 in the saddle-stitching section 27 of the paper post-processing device is changed depending on whether the image forming apparatus 10 is inkjet or electrophotographic.

[0082] The rotating cam 80 is similar to, for example, the first embodiment. That is, the radius from the rotation center of the rotating cam 80 to the circumferential surface and the rate of change of said radius are set so that the tip 79C of the folding blade 79 reaches the push-in position via the contact position from the separated position, and the moving speed of the tip 79C of the folding blade 79 increases until the tip 79C of the folding blade 79 reaches the contact position from the separated position, and then the moving speed of the tip 79C of the folding blade 79 is kept substantially constant until the tip 79C of the folding blade 79 reaches the push-in position from the contact position.

[0083] Here, the user operates the GUI displayed on the screen of the display unit 41 via the touch panel 43 to instruct the saddle-stitching process, sets multiple documents M into the image reading unit 11, and operates the start key on the operation unit 42.

[0084] The control unit 46 of the image forming apparatus 10 outputs a control signal to the paper post-processing device 20 via the interface 47 indicating whether the saddle-stitching process and the image forming apparatus 10 are using an inkjet method or an electrophotographic method. Simultaneously, the control unit 11 sequentially reads the image of each original document M, the image forming unit 12 forms the image of each original document M on the respective recording paper P, and these recording papers P are sequentially transported to the paper post-processing device 20.

[0085] The drive control unit 56 of the paper post-processing device 20 receives the above control signal through the interface 57 and sequentially accepts each recording paper P transported from the image forming apparatus 10. Based on the control signal, it determines whether the image forming apparatus 10 is an inkjet type or an electrophotographic type, and drives the saddle-stitching unit 27 to apply a staple process to the center of the stack of recording paper, fold the stack in the middle, and discharge the stack into the output tray 28.

[0086] At this time, if the drive control unit 56 of the paper post-processing device 20 determines that the image forming apparatus 10 is an inkjet type, it drives and controls the motors that rotate each folding roller 78 and the rotating cam 80, adjusting the rotation speed of the rotating cam 80 according to the rotation speed of the motor of each folding roller 78, so that the moving speed of the tip 79C of the folding blade 79 and the moving speed of the circumferential surface of each folding roller 78 are matched at the timing when the stack of recorded paper comes into contact with the circumferential surface of each folding roller 78.

[0087] As a result, when the stack of recording paper comes into contact with the circumferential surface of each folding roller 78, the surface of the recording paper follows the circumferential surface of each folding roller 78 and comes into contact with it, without the surface of the recording paper being rubbed against the circumferential surface of each folding roller 78. The tip 79C of the folding blade 79 pushes the center of the stack of recording paper into the nip area NP of each folding roller 78, and the center of the stack of recording paper is folded.

[0088] Furthermore, as described above, the radius from the rotation center of the rotating cam 80 to its circumferential surface and the rate of change of said radius are set so that the movement speed of the tip 79C of the folding blade 79 is kept approximately constant from the contact position to the pressing position. Therefore, even when the central part of the recording paper stack is pressed into the nip area NP, the movement speed of the tip 79C of the folding blade 79 does not deviate significantly from the movement speed of the circumferential surface of each folding roller 78. In addition, in the case of recording paper wet with ink, misalignment is less likely to occur between the overlapping recording papers. For this reason, the recording paper in the recording paper stack will not shift or tear.

[0089] On the other hand, when the paper post-processing device 20 determines that the image forming apparatus 10 is an electrophotographic system, the drive control unit 56 drives the motors that rotate each folding roller 78 and the rotating cam 80, adjusting the rotation speed of the rotating cam 80 according to the rotation speed of the motor for each folding roller 78, and matching the movement speed of the tip 79C of the folding blade 79 with the movement speed of the circumferential surface of each folding roller 78 at the moment when the center of the recording paper stack is pressed into the nip area NP of each folding roller 78 by the tip 79C of the folding blade 79.

[0090] As a result, the tip 79C of the folding blade 79 pushes the center of the stack of recording paper into the nip area NP of each folding roller 78, and when the center of the stack of recording paper is folded, only the top layer of recording paper in the stack is lifted up in the nip area NP of each folding roller 78 and is not pulled away from the lower layers of recording paper, and the stapled center of any of the recording papers does not shift or tear.

[0091] Furthermore, as described above, the radius from the rotation center of the rotating cam 80 to its circumferential surface and the rate of change of said radius are set so that the moving speed of the tip 79C of the folding blade 79 is kept approximately constant from the contact position to the pressed position. Therefore, even when the stack of recording paper comes into contact with the circumferential surface of each folding roller 78, the moving speed of the tip 79C of the folding blade 79 does not deviate significantly from the moving speed of the circumferential surface of each folding roller 78. In addition, the surface of the recording paper to which the toner is attached is dry, and wax adheres to the toner surface along with the toner, smoothing the surface of the recording paper and reducing the friction of the surface of the recording paper. For this reason, even if the surface of the recording paper is slightly rubbed against the circumferential surface of each folding roller 78 when the stack of recording paper comes into contact with the circumferential surface of each folding roller 78, the toner attached to the surface of the recording paper does not transfer to the circumferential surface of each folding roller 78, and the circumferential surface of each folding roller 78 does not become soiled with toner.

[0092] In each of the above embodiments, the paper post-processing device 20 is provided with a drive control unit 56, but the drive control unit 56 may be omitted, and the paper post-processing device 20 may be directly controlled by the control unit 46.

[0093] Furthermore, other types of cams different from the rotating cam 80 may be used. A variety of cams are available, and for example, a cam that converts horizontal motion into vertical motion may be used.

[0094] Furthermore, the configurations and processes of each embodiment and modified example described with reference to Figures 1 to 8 are merely examples of the present invention, and the present invention is not intended to be limited to these configurations and processes. [Explanation of symbols]

[0095] 10 Image forming apparatus 11 Image reading unit 12 Image forming unit 12A Image forming section 20 Paper Post-Processing Device 27. Saddle-stitched section 28 Output trays 77 Staple section 78 Folding Roller 79 Folding blade 80 RPM cam 41 Display section 42 Operation section 43 Touch panel 44 Storage section 46 Control Unit 47 Interfaces 56 Drive control unit 57 Interfaces

Claims

1. A paper post-processing device that processes paper received from an image forming apparatus that forms an image on paper, The image forming apparatus and an interface for inputting and outputting data or signals, A pair of folding rollers that are pressed against each other and rotated in opposite directions, A blade is supported so as to be movable in the direction of approach to and away from the nip area formed between each of the folding rollers, A transport unit for transporting the paper is provided between the nip area of ​​each folding roller and the blade. A drive unit that moves the blade in the approach-to-across direction relative to the nip area of ​​each folding roller, and pushes the stack of paper into the nip area of ​​each folding roller with the blade to fold it, The system includes a drive control unit that controls the drive unit and adjusts the speed at which the tip of the blade moved by the drive unit moves, A paper post-processing device wherein, when the drive control unit receives a signal through the interface indicating that the image forming apparatus is an inkjet type, it controls the drive unit to match the speed at which the tip of the blade moves to the speed at which the circumferential surface of the folding rollers when the stack of paper comes into contact with the circumferential surface of each folding roller, and when the drive control unit receives a signal through the interface indicating that the image forming apparatus is an electrophotographic type, it controls the drive unit to match the speed at which the tip of the blade moves to the speed at which the circumferential surface of the folding rollers when the tip of the blade pushes the central part of the stack of paper into the nip area of ​​each folding roller.

2. The system comprises an image forming apparatus that forms an image on paper using ink by an inkjet method, and a paper post-processing device that receives the paper from the image forming apparatus and processes the paper. The aforementioned paper processing device is: A pair of folding rollers that are pressed against each other and rotated in opposite directions, A blade is supported so as to be movable in the direction of approach to and away from the nip area formed between each of the folding rollers, A transport unit for transporting the paper is provided between the nip area of ​​each folding roller and the blade. A drive unit that moves the blade in the approach-to-across direction relative to the nip area of ​​each folding roller, and pushes the stack of paper into the nip area of ​​each folding roller with the blade to fold it, The drive unit comprises a drive control unit that controls the drive unit, The drive control unit drives the drive unit to match the speed at which the tip of the blade moves to the speed at which the circumferential surface of the folding roller moves at the timing when the stack of paper comes into contact with the circumferential surface of each folding roller. The drive unit comprises a rotating cam having a different radius from the center of rotation to the circumferential surface depending on the position on the circumferential surface, which contacts a contact roller provided at the end of the blade and pushes the blade toward the nip area of ​​each folding roller, thereby moving the blade toward the nip area, and a motor that rotates the rotating cam. The drive control unit controls the drive unit using the rotational speed of the rotating cam, which is calculated based on the radius from the center position of the rotating cam to a predetermined position on the circumferential surface of the rotating cam where the contact roller makes contact with the circumferential surface of each folding roller at the timing when the stack of paper comes into contact with the circumferential surface of each folding roller, and the rate of change of said radius, such that the moving speed of the blade and the moving speed of the circumferential surface of each folding roller match. A paper post-processing system in which the radius from the rotation center of the rotating cam to the circumferential surface and the rate of change of the radius are set such that the speed of movement of the tip of the blade increases from a distance position, which indicates the position of the tip of the blade that is furthest from the nip area, to a contact position, which indicates the position of the tip of the blade when the stack of paper comes into contact with the circumferential surface of each folding roller, and the speed of movement of the tip of the blade remains constant from the contact position to a push position, which indicates the position of the tip of the blade when the central part of the stack of paper is pushed into the nip area.

3. The system comprises an image forming apparatus that forms an image on paper using an electrophotographic method with a developer containing toner and wax, and a paper post-processing device that receives the paper from the image forming apparatus and processes the paper. The aforementioned paper processing device is: A pair of folding rollers that are pressed against each other and rotated in opposite directions, A blade is supported so as to be movable in the direction of approach to and away from the nip area formed between each of the folding rollers, A transport unit for transporting the paper is provided between the nip area of ​​each folding roller and the blade. A drive unit that moves the blade in the approach-to-across direction relative to the nip area of ​​each folding roller, and pushes the stack of paper into the nip area of ​​each folding roller with the blade to fold it, The drive unit comprises a drive control unit that controls the drive unit, The drive control unit drives the drive unit so that the speed at which the tip of the blade moves matches the speed at which the circumferential surface of the folding roller moves at the timing when the center of the stack of paper is pressed into the nip area of ​​each folding roller by the tip of the blade. The drive unit comprises a rotating cam having a different radius from the center of rotation to the circumferential surface depending on the position on the circumferential surface, which contacts a contact roller provided at the end of the blade and pushes the blade toward the nip area of ​​each folding roller, thereby moving the blade toward the nip area, and a motor that rotates the rotating cam. The drive control unit controls the drive unit using the rotational speed of the rotating cam, which is calculated based on the radius from the center position of the rotating cam to a predetermined position on the circumferential surface of the rotating cam where the contact roller makes contact at the moment the tip of the blade presses the central part of the stack of paper into the nip area of ​​each folding roller, and the rate of change of said radius, so that the moving speed of the blade and the moving speed of the circumferential surface of each folding roller match. A paper post-processing system in which the radius from the center of rotation of the rotating cam to the circumferential surface and the rate of change of the radius are set such that the speed of movement of the tip of the blade increases from a distance position, which indicates the position of the tip of the blade that is furthest from the nip area, until it reaches an intermediate position between the distance position and a push-in position, which indicates the position of the tip of the blade when the central part of the stack of paper is pushed into the nip area, and the speed of movement of the tip of the blade is kept constant from the intermediate position until it reaches the push-in position.

Images