Sheet processing device, image forming system, and control method

Abstract

To enable proper alignment of a plurality of sheets on a tray.SOLUTION: A sheet processing device 5 includes: a tray 35 on which each sheet 9 to be conveyed is stacked; a regulating member 37 provided at one end of the tray 35; a paddle member 50 that is provided on the tray 35 so as to be able to move up and down and that rotates in contact with the conveyed sheet 9, thereby causing one end of the sheet 9 to abut against the regulating member 37 and align; and a control unit 8 that determines the height position of the paddle member 50 on the tray 35 based on the number of sheets stacked on the tray 35 and sheet information on the conveyed sheet 9 and that controls the height position of the paddle member 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sheet processing apparatus, an image forming system, and a control method, and more particularly to a technique for aligning sheets on a tray. [Background technology]

[0002] Conventionally, a sheet processing apparatus equipped with a paddle member has been proposed for aligning sheets discharged from an image forming apparatus (for example, Patent Document 1). This sheet processing apparatus rotates the paddle member each time a sheet is discharged from the image forming apparatus, aligning the trailing edge of the sheet at a predetermined position on the tray. When aligning the sheets, the sheet processing apparatus lowers the paddle member onto the tray and rotates it. In conventional sheet processing apparatuses, when the number of sheets stacked on the tray reaches a predetermined number, the amount of movement of the paddle member when lowering it onto the tray is controlled to be small.

[0003] Recently, sheet processing devices equipped with paddle members have been installed in the body of an image forming apparatus (see, for example, Patent Document 2). When a sheet processing device is installed in the body of an apparatus, miniaturization of the sheet processing device is essential. Therefore, it is unavoidable to reduce the diameter of the paddle member used to align sheets. A smaller diameter paddle member makes it difficult to apply an appropriate conveying force to a sheet for sheet alignment. For example, if the base of the paddle member contacts the sheet, the conveying force increases, which may cause the sheet to buckle during sheet alignment. In contrast, if the tip of the paddle member only contacts the sheet, sufficient conveying force may not be obtained, potentially resulting in misalignment. Therefore, simply controlling the movement of the paddle member for each specified number of sheets, as in the prior art described above, poses a problem: sheets cannot be properly aligned. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-144911 [Patent Document 2] Japanese Patent Application Publication No. 2024-10926 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a sheet processing apparatus, an image forming system, and a control method that can properly align sheets. [Means for solving the problem]

[0006] In order to achieve the above object, the invention of claim 1 is a sheet processing apparatus comprising: a tray for loading each sheet to be transported; a regulating member provided at one end of the tray; a paddle member that is movable up and down on the tray and rotates in contact with the sheet to be transported, thereby causing one end of the sheet to abut against the regulating member and align it; and a control unit that determines the height position of the paddle member on the tray based on the number of sheets loaded on the tray and sheet information of the sheet to be transported, and controls the height position of the paddle member.

[0007] The invention according to claim 2 is the sheet processing apparatus of claim 1, characterized in that the control unit changes the height position of the paddle member every time one sheet is conveyed.

[0008] The invention of claim 3 is characterized in that, in the sheet processing device of claim 1, the sheet information includes sheet thickness information, and the control unit determines the height position of the paddle member based on the number of sheets and the thickness information.

[0009] The invention of claim 4 is characterized in that, in the sheet processing device of claim 3, the control unit determines the basis weight classification of the sheet based on the thickness information, and determines the height position of the paddle member based on a representative value predetermined for that basis weight classification.

[0010] The invention of claim 5 is characterized in that, in the sheet processing device of claim 3, the sheet information includes sheet size information, and the control unit corrects the determined height position of the paddle member based on the size information.

[0011] The invention of claim 6 is characterized in that, in the sheet processing apparatus of claim 5, when the sheet size indicated by the size information is larger than a predetermined size, the control unit corrects the height position of the paddle member to a lower height position than the determined height position.

[0012] The invention of claim 7 is characterized in that, in the sheet processing device of claim 3, the control unit corrects the determined height position of the paddle member depending on the image formation state on the front and back of the sheet being transported.

[0013] The invention of claim 8 is characterized in that, in the sheet processing device of claim 3, the control unit corrects the determined height position of the paddle member based on the amount of toner transferred to the sheet being transported.

[0014] The invention of claim 9 is characterized in that, in the sheet processing device of claim 3, the control unit acquires temperature information and humidity information, and corrects the determined height position of the paddle member based on the temperature information and the humidity information.

[0015] The invention of claim 10 is a sheet processing apparatus according to claim 1, further comprising: a holding member that holds the paddle member at its tip and changes the height position of the paddle member by swinging around a rotation axis inserted into its base end; and a swing arm that engages with the tip of the holding member to swing the holding member, wherein the control unit controls the height position of the paddle member by driving the swing arm to swing the holding member.

[0016] The invention of claim 11 is a sheet processing device of claim 1, characterized in that the paddle member has a rotating body and an elastic fin protruding outward from the outer peripheral surface of the rotating body, and by rotating the rotating body in a predetermined direction with the fin abutting against the sheet, the sheet is transported toward the regulating member and one end of the sheet is abutted against the regulating member.

[0017] The invention of claim 12 is a sheet processing device of claim 11, characterized in that the paddle member has a fin forming section that contacts the fins with the sheet to apply a conveying force to the sheet as the rotating body rotates in the predetermined direction, and a fin non-forming section that does not contact the fins with the sheet and does not apply a conveying force to the sheet.

[0018] The invention of claim 13 is a sheet processing device of claim 12, characterized in that multiple fins are formed at a predetermined interval in the fin forming section, and when any one of the multiple fins abuts against a sheet and elastically deforms, it does not interfere with other adjacent fins.

[0019] The invention of claim 14 is characterized in that, in the sheet processing device of claim 1, the control unit raises the paddle member when transporting the sheet toward the regulating member by rotating the paddle member at a determined height position.

[0020] The invention of claim 15 is an image forming system comprising an image forming device that transports a sheet and forms an image on the sheet while it is being transported, and a sheet processing device according to any one of claims 1 to 14, wherein the sheet processing device is configured to accept a sheet on which an image has been formed in the image forming device, and align one end of the sheet on the tray by abutting it against the regulating member.

[0021] The invention according to claim 16 is the image forming system according to claim 15, characterized in that the sheet processing apparatus is mounted on a body of the main body of the image forming apparatus.

[0022] The invention of claim 17 is a control method for a sheet processing apparatus comprising a tray for loading each sheet to be transported, a regulating member provided at one end of the tray, and a paddle member that is capable of being raised and lowered on the tray and that rotates in contact with the sheet to be transported, thereby causing one end of the sheet to abut against the regulating member and align it, characterized in that the height position of the paddle member on the tray is determined based on the number of sheets loaded on the tray and sheet information of the sheet to be transported, and the height position of the paddle member is controlled. [Effects of the Invention]

[0023] According to the present invention, it is possible to perform post-processing appropriate for the type of sheet. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a conceptual diagram showing the overall configuration of an image forming system. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a sheet processing apparatus. [Figure 3] FIG. 4 is a perspective view showing details of a drive mechanism for a paddle holding portion. [Figure 4] FIG. 2 is an enlarged perspective view of a paddle holding portion. [Figure 5] FIG. 10 is a side view showing the drive mechanism of the paddle holding portion. [Figure 6] FIG. 10 is an enlarged view showing a state in which the paddle member is lowered. [Figure 7] FIG. 10 is a view showing the sheet processing apparatus in a state where the paddle member is lowered. [Figure 8] 10A and 10B are diagrams showing examples of the arrangement of a plurality of fins provided on the outer peripheral surface of a paddle member. [Figure 9] 10A and 10B are diagrams illustrating an example of a sheet aligning operation performed by a control unit. [Figure 10] 10A and 10B are diagrams illustrating an example of a sheet aligning operation performed by a control unit. [Figure 11] FIG. 2 is a block diagram showing an example of the configuration of a control unit. [Figure 12] 10A and 10B are diagrams illustrating the height position of the paddle member determined by the position determining unit. [Figure 13] FIG. 2 illustrates an example of the configuration of a media detection unit. [Figure 14] 10A and 10B are diagrams illustrating an example of a change in the height position of a paddle member determined by a position determination unit. [Figure 15] FIG. 10 is a diagram showing representative values ​​of height positions of the paddle member determined for cardboard basis weight classifications. [Figure 16] 10 is a flowchart illustrating an example of a processing procedure performed by a control unit. [Figure 17] 10 is a flowchart illustrating an example of a detailed processing procedure of a height position determination process. [Figure 18] 10 is a flowchart illustrating an example of a detailed processing procedure of a paddle member driving process. [Figure 19] 10 is a diagram showing a conveying force applied to a sheet by two rotations of a paddle member. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Elements common to the embodiments described below are designated by the same reference numerals, and redundant description thereof will be omitted.

[0026] 1 is a conceptual diagram showing the overall configuration of an image forming system according to one embodiment of the present invention. This image forming system includes an image forming apparatus 1 and a sheet processing apparatus 5. The image forming apparatus 1 is configured as, for example, an MPF ​​(Multifunction Peripheral) and has a device body 1a equipped with multiple functions such as a scanning function, a printing function, and a copying function. The sheet processing apparatus 5 is mounted in a body space 6 of the device body 1a of the image forming apparatus 1 and performs post-processing such as stapling on sheets 9 on which images are formed and which are discharged from the image forming apparatus 1.

[0027] The image forming apparatus 1 has a scanner unit 2 on top of the apparatus main body 1a. The image forming apparatus 1 also has an operation panel 3 that can be operated by a user on the front side of the scanner unit 2. The operation panel 3 has a display unit that displays various setting screens and an operation unit that accepts operations by the user.

[0028] The image forming apparatus 1 also includes a printer unit 4 at the bottom of the apparatus main body 1a. The printer unit 4 forms an image on a sheet 9 and discharges the sheet 9 into a body space 6 between the printer unit 4 and the scanner unit 2. FIG. 1 shows the internal structure of the printer unit 4. As shown in FIG. 1, the printer unit 4 includes a paper feed conveyance unit 10 and an image forming unit 20. The printer unit 4 also includes a control unit 7 that controls the overall operation of the image forming apparatus 1.

[0029] The paper feed conveyance unit 10 feeds a sheet 9 from one of a plurality of paper feed trays 10a, 10b, and 10c, and conveys the sheet 9 along a conveyance path 13 formed inside the printer unit 4. The plurality of paper feed trays 10a, 10b, and 10c may each store different types of sheets 9, or may store the same type of sheets 9. Each of the paper feed trays 10a, 10b, and 10c is provided with a pickup roller 11 and a paper feed roller 12. The paper feed conveyance unit 10 drives the pickup roller 11 and paper feed roller 12 provided in one paper feed tray designated by the user, and feeds the sheet 9 toward the conveyance path 13. The paper feed conveyance unit 10 conveys the sheet 9 sent to the conveyance path 13 in the direction of arrow F1.

[0030] On the conveying path 13, a media detection unit 14, timing rollers 15, a secondary transfer roller 16, a fixing unit 17, and a discharge roller 18 are arranged.

[0031] The media detection unit 14 is a sensor that detects the type of sheet 9 when the sheet 9 passes a predetermined position on the conveying path 13. For example, the media detection unit 14 detects the thickness and basis weight of the sheet 9 being conveyed. The detection result by the media detection unit 14 is output to the control unit 7. The control unit 7 acquires the detection result by the media detection unit 14 as sheet information. Then, the control unit 7 controls the fixing temperature in the fixing unit 17 based on the sheet information. The control unit 7 also sends the sheet information acquired from the media detection unit 14 to the sheet processing device 5.

[0032] The timing roller 15 is composed of a pair of rollers. The timing roller 15 is a roller that adjusts the timing at which the sheet 9 is sent to the secondary transfer position by the secondary transfer roller 16. When the leading edge of the sheet 9 fed from the paper feed trays 10a, 10b, and 10c reaches the position of the timing roller 15, the paper feed conveying unit 10 temporarily stops conveying the sheet 9. Then, the paper feed conveying unit 10 drives the timing roller 15 in accordance with the timing at which the image that has been primarily transferred onto the intermediate transfer belt 22 in the image forming unit 20 is conveyed to the secondary transfer position, and conveys the sheet 9 toward the secondary transfer roller 16.

[0033] The sheet 9 sent out from the timing roller 15 has an image secondarily transferred onto it when it passes through a secondary transfer position by the secondary transfer roller 16. Then, the sheet 9 onto which the image has been secondarily transferred advances towards the fixing unit 17.

[0034] The image forming section 20 includes image forming units 21Y, 21M, 21C, and 21K corresponding to the colors yellow (Y), magenta (M), cyan (C), and black (K), respectively, and an intermediate transfer belt 22.

[0035] The image forming unit 21Y is a unit that forms an image of a color corresponding to Y. The image forming unit 21Y includes an image carrier 25, which is composed of a photosensitive drum or the like, a charger 26, an exposure device 27, and a developing device 28. The image carrier 25 has a photosensitive layer on the surface of a cylindrical body and rotates in a predetermined direction (clockwise). The charger 26, the exposure device 27, and the developing device 28 are arranged around the image carrier 25. The charger 26 charges the surface of the image carrier 25 to a predetermined electric charge. The exposure device 27 exposes the charged surface of the image carrier 25 based on image data, thereby forming an electrostatic latent image on the surface of the image carrier 25. The developing device 28 supplies toner to the surface of the image carrier 25 and visualizes the electrostatic latent image with the toner. As a result, an image (toner image) corresponding to the image data is formed on the surface of the image carrier 25. The other image forming units 21M, 21C, and 21K have the same configuration as image forming unit 21Y, and differ only in the color of the toner that they supply to image carrier 25. In other words, multiple image forming units 21Y, 21M, 21C, and 21K, each having the same configuration, are arranged at predetermined intervals.

[0036] The intermediate transfer belt 22 is an endless belt disposed above the image forming units 21Y, 21M, 21C, and 21K. The intermediate transfer belt 22 is stretched over a drive roller 23 disposed opposite the secondary transfer roller 16 and a driven roller 24 disposed a predetermined distance away from the drive roller 23. As the drive roller 23 is driven to rotate counterclockwise, the intermediate transfer belt 22 circulates in the direction indicated by arrow F2. The intermediate transfer belt 22 comes into contact with the secondary transfer roller 16 at the position of the drive roller 23.

[0037] Primary transfer rollers 29 are provided inside the intermediate transfer belt 22 at positions facing the image forming units 21Y, 21M, 21C, and 21K. A predetermined voltage is applied to the primary transfer rollers 29 while pressing the intermediate transfer belt 22 against the image carriers 25 of the image forming units 21Y, 21M, 21C, and 21K, thereby primarily transferring the images (toner images) formed on the image carriers 25 onto the intermediate transfer belt 22. The image forming units 21Y, 21M, 21C, and 21K primarily transfer Y, M, C, and K images onto the intermediate transfer belt 22 in order while superimposing the images, thereby forming a color image on the surface of the intermediate transfer belt 22. The images transferred to the intermediate transfer belt 22 are then secondarily transferred onto the sheet 9 at the position of the secondary transfer roller 16.

[0038] The fixing unit 17 applies heat and pressure to the sheet 9 on which the image has been formed, thereby fixing the image to the sheet 9. For example, the fixing unit 17 has a heating roller and a pressure roller, and applies heat and pressure to the sheet 9 at the nip between the heating roller and the pressure roller. The surface temperature of the heating roller is controlled by the control unit 7 to a temperature appropriate for the type of sheet. The sheet 9 on which the image has been fixed in the fixing unit 17 is discharged into the body space 6 via discharge rollers 18.

[0039] The sheet processing apparatus 5 receives sheets 9 discharged from the printer unit 4 as described above, aligns multiple sheets 9, and discharges them. FIG. 2 illustrates an exemplary configuration of the sheet processing apparatus 5. The sheet processing apparatus 5 includes a housing 30, a conveyance path 31, conveyance rollers 32 and 33, a sheet alignment unit 34, a post-processing unit 39, an output tray 41, and a control unit 8. The conveyance path 31, conveyance rollers 32 and 33, the sheet alignment unit 34, and the post-processing unit 39 are housed in the housing 30. An inlet 30a for receiving sheets 9 is provided on the right wall of the housing 30. The sheet processing apparatus 5 receives, through the inlet 30a, sheets 9 on which images are formed and discharged from the image forming apparatus 1, and conveys the sheets 9 along the conveyance path 31 within the housing 30. The conveyance rollers 32 and 33 are a pair of rollers arranged above and below the conveyance path 31, and convey the sheets 9 toward the sheet alignment unit 34.

[0040] When post-processing is not performed on the sheet 9, the sheet processing device 5 conveys the sheet 9 discharged from the conveyance roller 33 located at the most downstream side of the conveyance path 31 directly toward the discharge tray 41 as shown by the dashed line in Fig. 2, and stacks the sheet 9 on the discharge tray 41. The discharge tray 41 is configured to be movable in the vertical direction along a wall 40 erected inside the housing 30, and its height position can be adjusted according to the number of sheets 9 stacked on it. For example, the control unit 8 lowers the discharge tray 41 according to the number of sheets 9 stacked on it.

[0041] On the other hand, when post-processing is performed on sheets 9, the sheet processing device 5 operates the sheet alignment unit 34 to align multiple sheets 9. Then, with a predetermined number of sheets 9 aligned, the sheet processing device 5 drives the post-processing unit 39 to perform post-processing on the sheets 9 and discharge the sheets onto the paper output tray 41. The post-processing unit 39 performs, for example, a process of stapling multiple sheets 9. Note that in this embodiment, the post-processing performed by the post-processing unit 39 is exemplified by a process of stapling multiple sheets 9. However, the post-processing performed by the post-processing unit 39 is not limited to stapling.

[0042] The sheet alignment section 34 includes a tray 35 for aligning multiple sheets 9, a paddle holding section 36 provided on the tray 35, a regulating member 37 provided at one end of the tray 35, and a sheet pressing section 38.

[0043] The upper surface of the tray 35 is configured as a sheet placement surface on which the sheets 9 are placed. The tray 35 has an inclined sheet placement surface. For example, the sheet placement surface of the tray 35 is formed so that the leading edge side in the discharge direction of the sheets 9 discharged from the conveyance rollers 33 is higher and the trailing edge side is lower. The regulating member 37 is disposed on one end of the inclined tray 35 that is lower. The sheet alignment unit 34 aligns the trailing edges of the sheets 9 discharged from the conveyance rollers 33 by bringing the trailing edges of the sheets 9 into contact with the regulating member 37. For example, a plurality of regulating members 37 are disposed along the width direction of the tray 35. The post-processing unit 39 is disposed between the plurality of regulating members 37 and staples the edges of the plurality of sheets 9 that are aligned by contacting the regulating members 37.

[0044] The sheet pressing portion 38 presses down the surface of the sheet 9 when the sheet 9 abuts against the regulating member 37. The sheet pressing portion 38 is loosely inserted into the rotation shaft of the lower roller of the pair of rollers that make up the conveying roller 33, for example, and is capable of swinging around the rotation shaft.

[0045] The paddle holding unit 36 ​​holds the paddle member 50. The paddle member 50 is held by the paddle holding unit 36 ​​so that it can move up and down above the tray 35. In FIG. 2, the paddle member 50 is shown raised to a retracted position above the tray 35. This retracted position is the home position of the paddle member 50. When a sheet 9 is conveyed onto the tray 35, the paddle holding unit 36 ​​lowers the paddle member 50 so that it approaches the upper surface of the tray 35, and knocks the sheet 9 down onto the tray 35. The paddle holding unit 36 ​​also rotates the paddle member 50 to convey the sheet 9 downward in the inclined direction of the tray 35, causing the trailing edge of the sheet 9 to abut against the regulating member 37.

[0046] The paddle holding unit 36 ​​includes a holding member 53 that holds the paddle member 50, and a swing arm 55. The base end of the holding member 53 is attached to a rotating shaft 54. The holding member 53 is rotatably supported by the rotating shaft 54. The holding member 53 rotatably holds the paddle member 50 at its tip. The holding member 53 swings about the rotating shaft 54 ​​to adjust the height position of the paddle member 50 relative to the upper surface of the tray 35. The swing arm 55 has a base end fixed to a rotating shaft 56, and as the rotating shaft 56 rotates, the tip of the swing arm 55 swings up and down. The tip of the swing arm 55 engages with the tip of the holding member 53. Therefore, when the tip of the swing arm 55 swings up and down as the rotating shaft 56 rotates, the holding member 53 swings around the rotating shaft 54, changing the height position of the paddle member 50 held at the tip of the holding member 53.

[0047] The detailed configuration of the paddle holding unit 36 ​​will be described. Fig. 3 is a perspective view showing the details of the drive mechanism of the paddle holding unit 36. Fig. 4 is an enlarged perspective view of the paddle holding unit 36. Fig. 5 is a side view showing the drive mechanism of the paddle holding unit 36.

[0048] As shown in Fig. 3, the rotary shaft 56 that supports the swing arm 55 has its end rotatably supported by a bearing 56a provided in the housing 30. The paddle holder 36 is provided at the center of the longitudinal direction of the rotary shaft 56. The rotary shaft 56 also has lever members 68, 68 on both sides of the paddle holder 36. The lever members 68, 68 swing up and down as the rotary shaft 56 rotates. These lever members 68, 68 have the function of knocking down the sheet 9 conveyed onto the tray 35 onto the upper surface of the tray 35.

[0049] As shown in Fig. 3, a rotating disk 58 that is rotated by a motor 57 is provided on one end of the rotating shaft 56. As shown in Figs. 3 and 5, a cam 59 is formed on this rotating disk 58. The rotating disk 58 has a notch 58a at a predetermined position on its outer periphery. In addition, a position detection sensor 63 that detects the notch 58a is provided on the outside of the rotating disk 58.

[0050] A rod-shaped follower 60 is fixed to one end of the rotary shaft 56. One end of the follower 60 is fixed to the outer circumferential surface of the rotary shaft 56. The follower 60 abuts against the upper edge of the cam 59. A biasing member 61, such as a tension spring, is attached to the other end of the follower 60. One end of the biasing member 61 is fixed to the follower 60, and the other end is fixed to a mounting portion 62 provided on the housing 30. The biasing member 61 tensions and biases the other end of the follower 60 downward. Therefore, the follower 60 changes its posture with its center in contact with the upper edge of the cam 59. When the motor 57 rotates the turntable 58, the cam 59 rotates accordingly. Accordingly, the follower 60 swings around the rotary shaft 56 and changes its posture. As the posture of the follower 60 changes, the rotary shaft 56 rotates within a predetermined angle range. As a result, the swing arm 55 swings up and down.

[0051] A motor 64 is connected to one end of the rotating shaft 54 ​​that supports the holding member 53. The motor 64 rotates the rotating shaft 54. As shown in FIG. 4 , the holding member 53 has a pair of plate members 53a and 53b that are spaced a predetermined distance apart. The rotating shaft 54 ​​is loosely inserted into holes formed in the base ends of the pair of plate members 53a and 53b, and holds the base ends of the plate members 53a and 53b in a predetermined position. A drive belt 65 is disposed between the pair of plate members 53a and 53b of the holding member 53. As the rotating shaft 54 ​​rotates, the drive belt 65 circulates between the pair of plate members 53a and 53b, rotating the rotating shaft 66 that supports the paddle member 50. In other words, the motor 64 serves as a drive source for rotating the paddle member 50.

[0052] Furthermore, the pair of plate members 53a, 53b have protrusions 67 that protrude outward at their tips. The swing arm 55 has an elongated hole at its tip 55b, and the protrusions 67 are received in the elongated hole to engage with the tip of the holding member 53. As a result, the swing arm 55 swings around the rotation shaft 56 within a predetermined angle range, thereby raising and lowering the tip of the holding member 53.

[0053] As shown in FIG. 4 , the paddle members 50 are provided on both the left and right sides of the holding member 53. The paddle member 50 includes a rotating body 51 and multiple fins 52 protruding outward from the outer periphery of the rotating body 51. The rotating body 51 is a cylindrical member, and one end 66a of a rotating shaft 66 is attached to its center, rotating integrally with the rotating shaft 66. The fins 52 are made of an elastic material such as rubber and are elastically deformable. In this embodiment, an example is shown in which three fins 52 are attached to the periphery of the rotating body 51. When the motor 64 is driven and the rotating shaft 66 rotates, the paddle member 50 rotates the multiple fins 52 in a predetermined direction. At this time, the fins 52 of the paddle member 50 come into contact with the sheet 9 placed on the tray 35 and apply a conveying force that conveys the sheet 9 downward in the tilt direction of the tray 35.

[0054] FIG. 6 is an enlarged view showing the state in which the paddle member 50 is lowered. FIG. 7 is a view showing the sheet processing apparatus 5 in the state in which the paddle member 50 is lowered. As shown in FIG. 6, when the rotary plate 58 rotates and the cam 59 pushes up the follower 60, the rotary shaft 56 rotates a predetermined angle. Accordingly, the tip 55b of the swing arm 55 lowers. As the tip 55b of the swing arm 55 lowers, the holding member 53 lowers the paddle member 50 and brings it closer to the upper surface of the tray 35. As the paddle member 50 rotates counterclockwise and lowers, the elastic fins 52 sequentially contact the sheet 9 and apply a conveying force to the sheet 9. Due to this conveying force, the sheet 9 is conveyed on the tray 35 toward the regulating member 37, and is aligned so that the trailing edge of the sheet 9 abuts against the regulating member 37.

[0055] FIG. 8 is a diagram showing an example of the arrangement of multiple fins 52 provided on the outer peripheral surface of a paddle member 50. The paddle member 50 has three fins 52 provided on the outer peripheral surface of a rotor 51. These three fins 52 are not evenly provided across the entire outer peripheral surface of the rotor 51. That is, the paddle member 50 has a fin-formed portion R1 on the outer peripheral surface of the rotor 51 where the fins 52 are formed, and a fin-free portion R2 on which no fins 52 are formed. For example, the fin-formed portion R1 is formed in a region covering approximately half the circumference of the outer peripheral surface of the rotor 51, and the fin-free portion R2 is also formed in a region covering approximately half the circumference of the outer peripheral surface of the rotor 51. The fin-formed portion R1 has three fins 52 spaced apart at a predetermined angle θ1. On the other hand, the fin-free portion R2 is formed within a range of a predetermined angle θ2. Therefore, when the rotating body 51 of the paddle member 50 is rotated while the paddle member 50 is lowered toward the tray 35, there are periods when the fins 52 contact the sheet 9 and periods when the fins 52 do not contact the sheet 9. During the periods when the fins 52 do not contact the sheet 9, no conveying force is applied to the sheet 9. In contrast, during the periods when the fins 52 contact the sheet 9, a conveying force is applied to the sheet 9. The paddle member 50 conveys the sheet 9 toward the regulating member 37 by periodically generating periods when the fins 52 contact the sheet 9 and periods when they do not contact the sheet 9.

[0056] When the three fins 52 provided on the paddle member 50 come into contact with a sheet 9 placed on the tray 35, they elastically deform, generating a frictional force between the sheet 9 and the fins 52. This frictional force is applied to the sheet 9 as a conveying force for conveying the sheet 9. The paddle member 50 is configured so that when any one of the three fins 52 comes into contact with the sheet 9 and elastically deforms, it does not interfere with the adjacent fins 52. This prevents multiple fins 52 from contacting the sheet 9 at the same time. If multiple fins 52 were to come into contact with the sheet 9 at the same time, the conveying force of the sheet 9 would become too large, causing the rear end of the sheet 9 to hit the regulating member 37 and buckle. To prevent this, the paddle member 50 is configured so that each fin 52 does not interfere with the adjacent fins 52 even when it elastically deforms.

[0057] The control unit 8 of the sheet processing apparatus 5 controls the operation of aligning the sheet 9 discharged from the image forming apparatus 1 onto the tray 35. FIGS. 9 and 10 are diagrams illustrating an example of the sheet alignment operation performed by the control unit 8.

[0058] As shown in Fig. 9(a), the control unit 8 receives the sheet 9 discharged from the image forming apparatus 1 with the paddle member 50 raised to the retracted position. Thereafter, as shown in Fig. 9(b), when the trailing end of the sheet 9 is discharged onto the tray 35, the control unit 8 starts the operation of lowering the paddle member 50 from the retracted position. As the paddle member 50 descends, the sheet 9 discharged onto the tray 35 hits the paddle member 50 and the lever member 68, and is forcibly knocked down onto the tray 35, as shown in Fig. 9(c).

[0059] The control unit 8 rotates the paddle member 50 as the paddle member 50 starts to descend. The timing for starting the rotation of the paddle member 50 may be the same as the timing when the paddle member 50 starts to descend, or may be a predetermined time after the timing when the paddle member 50 starts to descend. The control unit 8 determines the height position of the paddle member 50, and stops the downward movement of the paddle member 50 when the paddle member 50 descends to the determined height position. After stopping the downward movement of the paddle member 50, the control unit 8 continues to rotate the paddle member 50. At this time, as shown in FIG. 10( a), the fins 52 provided on the paddle member 50 contact the upper surface of the sheet 9 and rotate in an elastically deformed state. Due to the rotation of the paddle member 50, the sheet 9 moves in the direction of arrow A1, and the rear end of the sheet 9 abuts against the restricting member 37. The control unit 8 then raises the paddle member 50 to the retracted position, making it ready to accept the next sheet 9. The control unit 8 repeats the above-described operations to stack a plurality of sheets 9 on the tray 35 in an aligned state, as shown in FIG. 10(b).

[0060] The sheet processing device 5 described above is mounted in the body space 6 of the device body 1a of the image forming device 1. Therefore, compared to the paddle member mounted in a post-processing device arranged adjacent to and alongside the image forming device 1, the paddle member 50 built into the sheet processing device 5 is made smaller, and the outer diameter of the paddle member 50 is reduced. Therefore, if the base portions of the fins 52 hit the sheet 9 when aligning the sheet 9, the conveying force becomes too large, which may cause the sheet 9 to buckle. Furthermore, if the tip portions of the fins 52 only hit the sheet 9 when aligning the sheet 9, it may not be possible to apply a sufficient conveying force to the sheet 9, which may result in misalignment.

[0061] Therefore, the control unit 8 of this embodiment controls the paddle member 50 so that an appropriate conveying force is applied to the sheet 9 when the paddle member 50 is driven. Specifically, the control unit 8 determines the height position of the paddle member 50 above the tray 35 based on the number of sheets 9 stacked on the tray 35 and sheet information about the sheet 9 to be conveyed. Then, based on the determined height position, the control unit 8 controls the height position of the paddle member 50 so that an appropriate conveying force is applied to the sheet 9. The control unit 8 will be described in detail below.

[0062] 11 is a block diagram showing an example of the configuration of the control unit 8. The control unit 8 includes a CPU 70, a storage unit 71, and a communication unit 72. The CPU 70 is a hardware processor that reads and executes a computer-readable program 73. The storage unit 71 is a non-volatile storage device configured from a hard disk drive (HDD), a solid state drive (SSD), or the like. The storage unit 71 stores in advance the program 73 to be executed by the CPU 70. The communication unit 72 communicates with the control unit 7 provided in the image forming apparatus 1.

[0063] The CPU 70 executes the program 73 to control the operation of each unit in the sheet processing apparatus 5. For example, the CPU 70 executes the program 73 to function as a position determination unit 74 and a drive control unit 75.

[0064] The position determination unit 74 determines the height position of the paddle member 50. Fig. 12 is a diagram showing the height position H of the paddle member 50 determined by the position determination unit 74. As shown in Fig. 12, the position determination unit 74 determines the distance between the upper surface of the tray 35 and the center of rotation of the rotating body 51 in the normal direction of the tray 35 as the height position H of the paddle member 50.

[0065] For example, each time a sheet 9 is conveyed from the image forming apparatus 1, the position determination unit 74 determines the height position H of the paddle member 50 that can apply an optimal conveying force to align the sheet 9. The position determination unit 74 determines the height position of the paddle member 50 in accordance with the number of sheets 9 stacked on the tray 35 so that the small-diameter paddle member 50 can apply an appropriate conveying force to the sheet 9 placed on the tray 35.

[0066] Furthermore, the height position of the uppermost sheet 9 stacked on the tray 35 varies depending on the thickness of the sheet 9. Therefore, the position determination unit 74 acquires sheet information from the control unit 7 of the image forming apparatus 1 via the communication unit 72, and determines the height position H of the paddle member 50 based on the sheet information. As described above, when the sheet 9 is being transported along the transport path 13, the control unit 7 acquires the detection result from the media detection unit 14 as sheet information and sends it to the sheet processing apparatus 5. Therefore, the position determination unit 74 can determine the height position H of the paddle member 50 based on the sheet information of the sheet 9 being transported in the image forming apparatus 1.

[0067] FIG. 13 is a diagram showing an example of the configuration of the media detection unit 14. The media detection unit 14 has a transmission light source 14a, a reflection light source 14b, and a light-receiving element 14c. The transmission light source 14a is disposed on one side of the transport path 13 for the sheet 9. The reflection light source 14b and the light-receiving element 14c are disposed on the other side of the transport path 13 for the sheet 9. For example, the light-receiving element 14c is disposed in a position facing the transmission light source 14a across the transport path 13. When the sheet 9 is transported along the transport path 13, the media detection unit 14 alternately turns on the transmission light source 14a and the reflection light source 14b. When the transmission light source 14a is turned on, the light-receiving element 14c detects light transmitted through the sheet 9. When the reflection light source 14b is turned on, the light-receiving element 14c detects light reflected by the sheet 9. The light transmittance varies depending on the thickness (basis weight) of the sheet 9. Furthermore, the reflectance of the sheet 9 changes depending on the surface condition of the sheet 9. Therefore, the media detection unit 14 can detect the physical properties of the sheet 9 by sequentially turning on the transmission light source 14a and the reflection light source 14b and detecting the transmitted light and reflected light with the light receiving element 14c. The physical properties of the sheet 9 include the thickness (basis weight) and surface condition of the sheet 9. The control unit 7 of the image forming apparatus 1 generates sheet information indicating the physical properties of the sheet 9 based on the detection results of the media detection unit 14, and sends the sheet information to the control unit 8 of the sheet processing device 5. The sheet information sent from the control unit 7 includes at least thickness information of the sheet 9.

[0068] Based on the number of sheets 9 stacked on tray 35 and thickness information of the sheets 9, position determination unit 74 determines height position H of paddle member 50 so that a constant distance is maintained between the uppermost sheet 9 of the sheet stack stacked on tray 35 and paddle member 50. For example, when the first sheet 9 is transported to the sheet processing device 5 after image forming apparatus 1 starts executing a print job, position determination unit 74 calculates height position H1 of paddle member 50 for aligning the first sheet 9 based on the following equation (1).

[0069]

number

[0070] In the above formula 1, t1 is the thickness of the first sheet 9. The position determination unit 74 assigns a value to t1 based on the thickness information in the sheet information. Therefore, the value of t1 varies depending on the type of sheet 9 (thin paper, regular paper, thick paper). For example, if the sheet 9 is thin paper, a value of t1=0.066 [mm] is assigned; if it is regular paper, a value of t1=0.089 [mm] is assigned; and if it is thick paper, a value of t1=0.15 [mm] is assigned.

[0071] In addition, in the above formula 1, h1 is a reference height position that is set in advance depending on the type of sheet 9, such as thin paper, regular paper, or thick paper. For example, if the sheet 9 is regular paper or thick paper, the conveying force of the paddle member 50 needs to be increased to a certain extent. On the other hand, if the sheet 9 is thin paper, if the conveying force of the paddle member 50 is too large, the sheet 9 may buckle. Therefore, a value such as h1=11.4 [mm] is set when the sheet 9 is regular paper or thick paper, and h1=12.4 [mm] is set when the sheet 9 is thin paper.

[0072] Furthermore, when the second or subsequent sheet 9 is transported to the sheet processing device 5, the position determination unit 74 determines the height position Hn of the paddle member 50 when aligning the second or subsequent nth sheet 9 based on the following equation 2.

[0073]

number

[0074] In the above formula 2, ti is the thickness of the ith sheet 9. The position determination unit 74 substitutes the value of ti based on the thickness information of the ith sheet 9. H1 is the height position of the paddle member 50 when aligning the first sheet 9, calculated by formula 1.

[0075] In addition, in the above equation (2), hc is a correction term that is set when the type of sheet 9 conveyed from the image forming apparatus 1 changes during execution of a print job. For example, if the sheet 9 changes from plain paper or thick paper to thin paper during execution of a print job, hc = +1 [mm] is set. When the sheet 9 changes from plain paper or thick paper to thin paper, it is necessary to reduce the conveying force of the paddle member 50 to prevent buckling of the sheet 9. Therefore, it is necessary to increase the height position of the paddle member 50, and hc = +1 [mm] is set. Furthermore, for example, if the sheet 9 changes from thin paper to plain paper or thick paper during execution of a print job, hc = -1 [mm] is set. When the sheet 9 changes from thin paper to plain paper or thick paper, it is necessary to increase the conveying force of the paddle member 50 to properly align the sheet 9. Therefore, it is necessary to lower the height position of the paddle member 50, and hc = -1 [mm] is set. If the type of sheet 9 is not changed during execution of a print job, hc=0.

[0076] Based on the above equations 1 and 2, the position determination unit 74 calculates the height position of the paddle member 50 when aligning the sheet 9 conveyed from the image forming apparatus 1 on the tray 35. In other words, the position determination unit 74 calculates the optimum height position of the paddle member 50 for each sheet 9.

[0077] 14 is a diagram illustrating an example of changes in the height position of the paddle member 50 determined by the position determination unit 74. Note that FIG. 14 illustrates an example in which the type of sheet 9 does not change during execution of a print job. The position determination unit 74 determines the height position of the paddle member 50 each time a sheet 9 is received from the image forming apparatus 1. In other words, the position determination unit 74 determines the height position at which an optimal conveying force can be applied to each sheet 9.

[0078] 14, when the sheets 9 are cardboard or plain paper, the height position of the paddle member 50 when aligning the first sheet 9 is lower than when the sheets 9 are thin paper. This allows a larger conveying force to be applied to the sheet 9 when the sheet 9 is cardboard or plain paper than when the sheet 9 is thin paper, preventing misalignment in which the trailing edge of the sheet 9 does not reach the regulating member 37. Conversely, when the sheet 9 is thin paper, a smaller conveying force can be applied than when the sheet 9 is plain paper or cardboard, preventing the trailing edge of the sheet 9 from hitting the regulating member 37 too hard and causing buckling.

[0079] When aligning the second or subsequent sheet 9, the position determining unit 74 determines the height position of the paddle member 50 to be higher than the previous height position, depending on the thickness of the sheet 9 conveyed from the image forming apparatus 1. As a result, as shown in FIG. 14 , the height position of the paddle member 50 rises little by little each time the number of sheets 9 stacked on the tray 35 increases by one. Therefore, the compact paddle member 50 can apply an optimal conveying force to the topmost sheet 9 even when multiple sheets 9 are stacked on the tray 35.

[0080] The position determination unit 74 may determine the height position of the paddle member 50 by sequentially calculating Equation 1 or Equation 2 each time a sheet 9 is conveyed from the image forming apparatus 1. However, the method for determining the height position by the position determination unit 74 is not limited to this. For example, the position determination unit 74 may hold a lookup table, as shown in FIG. 14, that can determine the height position of the paddle member 50 depending on the type and number of sheets 9 stacked, and determine the height position of the paddle member 50 by referencing the lookup table. In this case, the time required for calculation processing can be shortened, and the position determination unit 74 can efficiently determine the height position of the paddle member 50.

[0081] There are various types of sheets 9 used for image formation in the image forming apparatus 1. For example, even when cardboard is used as the sheet 9, the basis weight of the cardboard is 120 g / m 2 , 200g / m2 , 300g / m 2 There are various values ​​such as the above. Also, the tray 35 of the sheet processing device 5 installed in the body space 6 of the image forming apparatus 1 has a limit on the number of sheets that can be loaded depending on the basis weight. For example, if the basis weight is 120 g / m 2 In the case of thick paper of 200 g / m², the number of sheets that can be loaded on the tray 35 is 30. 2 In the case of thick paper of 1000 g / m², the number of sheets that can be loaded on the tray 35 is 16. 2 In the case of thick paper, the number of sheets that can be loaded on the tray 35 is five. In such a case, the position determination unit 74 may determine the basis weight category of the sheet 9 based on the thickness information of the sheet 9, and determine the height position of the paddle member 50 based on the basis weight category. Here, the basis weight category is a category set according to the type of sheet 9, such as thick paper, regular paper, or thin paper. For example, if the basis weight is 120 g / m 2 The sheet 9 described above falls into the cardboard basis weight category.

[0082] FIG. 15 shows representative values ​​of the height position of the paddle member 50 determined for cardboard basis weight classifications. In the example shown in FIG. 15, the tray 35 can accommodate five sheets of cardboard A, 16 sheets of cardboard B, and 30 sheets of cardboard C. When the sheet 9 is cardboard, fluctuations in the conveying force due to fluctuations in the height of the paddle member 50 are tolerable within a certain range W, such as ±1 mm. Therefore, when the basis weight classification is cardboard, the position determination unit 74 determines the height position of the paddle member 50 based on a cardboard representative value, which is the median value of the certain range W, as shown in FIG. 15. In this case, when the position determination unit 74 determines that the sheet 9 is cardboard based on the thickness information of the sheet 9, it reads a cardboard representative value corresponding to the number of sheets loaded on the tray 35 from a lookup table and determines the height position of the paddle member 50 based on the read cardboard representative value. The position determination unit 74 may also determine the height position by substituting the number of loaded sheets into a linear function representing the cardboard representative value. 15 illustrates only the basis weight classification of thick paper, but it is not limited to thick paper. For example, a plain paper representative value may be predetermined for plain paper as well, as described above. A thin paper representative value may also be predetermined for thin paper.

[0083] Furthermore, the position determination unit 74 may determine the height position of the paddle member 50 based on the thickness information of the sheet 9 as described above, and then correct the height position of the paddle member 50 based on information other than the thickness information. Examples of information other than the thickness information include size information of the sheet 9, the image formation state on both the front and back sides of the sheet 9, the amount of toner transferred to the sheet 9, temperature information, and humidity information.

[0084] When a large sheet 9 is being conveyed, a large conveying force is required to prevent the sheet 9 from not reaching the regulating member 37. On the other hand, when a small sheet 9 is being conveyed, a small conveying force is required to prevent the sheet 9 from buckling after reaching the regulating member 37. Therefore, the position determination unit 74 corrects the height position of the paddle member 50 lower or higher depending on the size information of the sheet 9. Specifically, if the size of the sheet 9 is larger than a predetermined size, the position determination unit 74 corrects the height position of the paddle member 50 lower. On the other hand, if the size of the sheet 9 is smaller than the predetermined size, the position determination unit 74 corrects the height position of the paddle member 50 higher. Note that the size information of the sheet 9 is included in the sheet information.

[0085] The position determination unit 74 also corrects the height position of the paddle member 50 depending on the image formation status on both the front and back sides of the sheet 9. When an image is formed on only one side of the sheet 9, the friction coefficient of the sheet 9 tends to be high on the side without the image, requiring a large conveying force to prevent the sheet 9 from not reaching the regulating member 37. In contrast, when images are formed on both sides of the sheet 9, the friction force between the two sheets 9 is small, so the sheet 9 tends to be easily conveyed even with a small conveying force. Therefore, the position determination unit 74 corrects the height position of the paddle member 50 to be low when an image is formed on only one side of the sheet 9. Furthermore, the position determination unit 74 corrects the height position of the paddle member 50 to be high when images are formed on both the front and back sides of the sheet 9. The control unit 8 can simply obtain information regarding the image formation status on both the front and back sides of the sheet 9 from the control unit 7 of the image forming apparatus 1.

[0086] Furthermore, the position determination unit 74 corrects the height position of the paddle member 50 in accordance with the amount of toner transferred to the sheet 9. When the amount of toner transferred to the sheet 9 is small, the frictional force between the two sheets 9 increases, requiring a large conveying force. On the other hand, when the amount of toner transferred to the sheet 9 is large, the frictional force between the two sheets decreases, requiring a small conveying force. Therefore, the position determination unit 74 corrects the height position of the paddle member 50 to be lower when the amount of toner is less than a predetermined amount. Furthermore, the position determination unit 74 corrects the height position of the paddle member 50 to be higher when the amount of toner is greater than a predetermined amount. The control unit 8 may obtain information regarding the amount of toner transferred to the sheet 9 from the control unit 7 of the image forming apparatus 1.

[0087] Furthermore, the position determination unit 74 corrects the height position of the paddle member 50 based on the temperature information and humidity information. For example, under high temperature and humidity conditions, a large conveying force is required due to the moisture contained in the sheet 9. Therefore, the position determination unit 74 corrects the height position of the paddle member 50 to be lower when the temperature information is equal to or higher than a predetermined temperature and the humidity information is equal to or higher than a predetermined humidity. The control unit 8 can obtain the temperature information and humidity information from a temperature sensor and a humidity sensor (not shown) mounted in the image forming apparatus 1.

[0088] The drive control unit 75 drives the motors 57 and 64 to operate the paddle member 50, thereby aligning the trailing edges of multiple sheets 9 on the tray 35. Each time a sheet 9 is conveyed, the drive control unit 75 drives the motor 57 to position the sheet 9 at the height determined by the position determination unit 74. For example, the drive control unit 75 determines the number of pulses to drive the motor 57 based on the height determined by the position determination unit 74. The drive control unit 75 then provides a drive signal with the determined number of pulses to the motor 57, thereby rotating the turntable 58 by a predetermined angle. As a result, the paddle member 50 descends to the height determined by the position determination unit 74. The drive control unit 75 also drives the motor 64 at a predetermined timing to rotate the paddle member 50. As a result, an optimal conveying force is applied to the topmost sheet 9 placed on the tray 35. After aligning the sheet 9, the drive control unit 75 stops the motor 64 and drives the motor 57 to return the paddle member 50 to the retracted position. The drive control unit 75 repeats this operation every time a sheet 9 is discharged from the image forming apparatus 1.

[0089] The drive control unit 75 aligns the sheet 9 ejected from the image forming apparatus 1 on the tray 35 by rotating the paddle member 50, for example, twice. At this time, if a predetermined condition is met, the drive control unit 75 may control the paddle member 50 to rise at a predetermined timing before the paddle member 50 completes its two rotations. Here, the predetermined condition refers to, for example, a condition under which the sheet 9 ejected from the image forming apparatus 1 is likely to buckle. For example, the predetermined condition is met when the sheet 9 is a specific paper type. The predetermined condition is also met when the temperature and humidity are in a predetermined state. Furthermore, the predetermined condition is also met when a predetermined setting is included in the print job settings. If such a condition is met, the control unit 8 raises the paddle member 50 at a predetermined timing before the paddle member 50 completes its two rotations, thereby weakening the conveying force of the sheet 9 and preventing the sheet 9 from buckling. When raising the paddle member 50 before the two rotations of the paddle member 50 are completed, the control unit 8 may raise the paddle member 50 in stages. However, instead of raising the paddle member 50 in stages, the control unit 8 may raise the paddle member 50 continuously.

[0090] 16 is a flowchart showing an example of a processing procedure performed by control unit 8. Control unit 8 waits until a paper feeding operation is started by image forming apparatus 1 executing a print job (step S10). When the paper feeding operation is started in image forming apparatus 1 (YES in step S10), control unit 8 acquires sheet information of the sheet 9 being conveyed from image forming apparatus 1 (step S11). Control unit 8 reads thickness information of sheet 9 from the sheet information acquired from image forming apparatus 1 (step S12). Then, control unit 8 determines the height position when driving paddle member 50 to move up and down (step S13).

[0091] 17 is a flowchart showing an example of detailed processing procedures for the height position determination process (step S13). The control unit 8 determines the height position of the paddle member 50 based on thickness information read from the sheet information (step S20). At this time, the control unit 8 may determine the height position of the paddle member 50 by performing calculations based on the number of sheets 9 stacked on the tray 35 and the thickness information of the sheets 9 using the above equation 1 or 2. Alternatively, the control unit 8 may determine the height position of the paddle member 50 by referring to a lookup table.

[0092] Next, the control unit 8 acquires information to be referenced when correcting the height position determined in step S20 (step S21). For example, the control unit 8 acquires size information of the sheet 9, information about the image formation state, information about the toner amount, temperature information, environmental information, etc. After acquiring the information for correction, the control unit 8 first determines the size of the sheet 9 based on the size information (step S22). Next, the control unit 8 determines the image formation state on both the front and back sides of the sheet 9 (step S23). Next, the control unit 8 determines the amount of toner transferred to the sheet 9 (step S24). Furthermore, the control unit 8 determines the temperature information and environmental information (step S25). Then, the control unit 8 determines whether or not the height position of the paddle member 50 needs to be corrected based on the determination results of steps S22 to S25 (step S26).

[0093] If correction is necessary (YES in step S26), the control unit 8 corrects the height position of the paddle member 50 based on the determination results of steps S22 to S25 (step S27). This changes the height position when the paddle member 50 is driven. On the other hand, if correction is not necessary (NO in step S26), the processing of step S27 is not performed. In this case, the height position determined in step S20 is used as the height position when the paddle member 50 is driven.

[0094] Returning to the flowchart of Fig. 16, once the control unit 8 has determined the height position of the paddle member 50, it drives the paddle member 50 (step S14). At this time, the control unit 8 controls the height position of the paddle member 50 based on the height position determined in step S13.

[0095] 18 is a flowchart showing an example of a detailed processing procedure of the paddle member driving process (step S14). The control unit 8 waits until the trailing edge of the sheet 9 is discharged from the image forming apparatus 1 (step S30). At this time, the paddle member 50 is raised to the retracted position. When the trailing edge of the sheet 9 is discharged from the image forming apparatus 1 (YES in step S30), the control unit 8 moves the paddle member 50 to the height position determined in step S13 (step S31). That is, the control unit 8 starts driving the motor 57. As a result, the paddle member 50 descends from the retracted position, and the sheet 9 discharged onto the tray 35 is knocked down onto the upper surface of the tray 35.

[0096] When the paddle member 50 starts to descend, the control unit 8 starts the rotation operation of the paddle member 50 for the first rotation at a predetermined timing (step S32). That is, the control unit 8 starts the operation of driving the motor 64 to rotate the paddle member 50 once. Thereafter, the control unit 8 waits until the first rotation of the paddle member 50 is completed (step S33). When the first rotation of the paddle member 50 is completed (YES in step S33), the control unit 8 starts the rotation operation of the paddle member 50 for the second rotation (step S34).

[0097] When the second rotation operation is started, the control unit 8 determines whether a predetermined condition is met (step S35). That is, the control unit 8 determines whether a condition that makes the sheet 9 prone to buckling is met as a predetermined condition. If the predetermined condition is met (YES in step S35), the control unit 8 waits until it is time to start lifting the paddle member 50 (step S36). When it is time to start lifting the paddle member 50 (YES in step S36), the control unit 8 drives the motor 57 to start lifting the paddle member 50 (step S37). Thereafter, when the second rotation of the paddle member 50 is completed (YES in step S38), the control unit 8 returns the paddle member 50 to the retracted position (step S39).

[0098] On the other hand, if the predetermined condition is not met (NO in step S35), the control unit 8 does not raise the paddle member 50, but keeps the paddle member 50 at the determined height position. That is, the control unit 8 waits until the second rotation of the paddle member 50 is completed (step S38). Then, when the second rotation of the paddle member 50 is completed (YES in step S38), the control unit 8 drives the motor 57 to return the paddle member 50 to the retracted position (step S39).

[0099] Returning to the flowchart in Fig. 16 again, when the driving of the paddle member 50 as described above is completed, the control unit 8 determines whether or not there is a subsequent sheet 9 (step S15). If there is a subsequent sheet 9 (YES in step S15), the processing by the control unit 8 returns to step S11, and the above-mentioned processing is repeated. As a result, multiple sheets 9 are piled up on the tray 35, and the trailing ends of the multiple sheets 9 are aligned.

[0100] If there are no subsequent sheets 9 (NO in step S15), the control unit 8 drives the post-processing unit 39 to perform post-processing on the multiple sheets 9 stacked on the tray 35 (step S16). Thereafter, the control unit 8 drives the discharge means (not shown) to discharge the sheet stack on the tray 35 to the paper discharge tray 41 (step S17). This completes the processing by the control unit 8.

[0101] FIG. 19 shows the conveying force applied to the sheet 9 by the paddle member 50 making two rotations. FIG. 19(a) shows the conveying force applied to the sheet 9 when the paddle member 50 does not rise during the second rotation. As shown in FIG. 19(a), during one rotation of the paddle member 50, three fins 52 sequentially contact the sheet 9 and apply a conveying force to the sheet 9. Therefore, during one rotation of the paddle member 50, the conveying force appears as three mountain-shaped waveforms. If the paddle member 50 does not rise during the second rotation, the conveying force during the second rotation appears as three mountain-shaped waveforms, similar to the first rotation. The sheet 9 receives the conveying force appearing as these six mountain-shaped waveforms and is conveyed toward the regulating member 37.

[0102] On the other hand, if a predetermined condition is met, the paddle member 50 begins to rise during the second rotation. In this case, the conveying force appears as shown in FIG. 19(b) or 19(c). For example, if the control unit 8 rapidly raises the paddle member 50 during the second rotation, the number of mountain-shaped waveforms appearing as the conveying force can be reduced, as shown in FIG. 19(b). In the example of FIG. 19(b), the third mountain-shaped waveform disappears during the second rotation of the paddle member 50. In this case, the conveying force applied to the sheet 9 can be reduced. In particular, the conveying force applied after the trailing edge of the sheet 9 hits the restricting member 37 can be eliminated. This prevents the sheet 9 from buckling.

[0103] Furthermore, by slowly raising the paddle member 50 midway through the second rotation, the control unit 8 can gradually reduce the magnitude of the mountain waveforms appearing as a conveying force, as shown in FIG. 19(c). In the example of FIG. 19(c), during the second rotation of the paddle member 50, the second mountain waveform is smaller than the first mountain waveform, and the third mountain waveform is further smaller than the second mountain waveform. In this case, too, the conveying force applied to the sheet 9 can be reduced. In particular, the conveying force applied after the trailing edge of the sheet 9 hits the restricting member 37 can be reduced. This can prevent the sheet 9 from buckling.

[0104] As described above, the sheet processing apparatus 5 of this embodiment is mounted in the body space 6 of the apparatus body 1a of the image forming apparatus 1. Because the body space 6 of the image forming apparatus 1 is a narrow space between the printer unit 4 and the scanner unit 2, the sheet processing apparatus 5 is subject to height restrictions. Therefore, the paddle member 50 mounted in the sheet processing apparatus 5 is reduced in diameter. The sheet processing apparatus 5 of this embodiment is configured to apply an appropriate conveying force to the sheet 9 even when using a reduced-diameter paddle member 50. That is, the sheet processing apparatus 5 is configured to determine the height position of the paddle member 50 above the tray 35 based on the number of sheets stacked on the tray 35 and sheet information about the sheet 9 to be conveyed, and control the height position of the paddle member 50. This configuration makes it possible to apply an appropriate conveying force to the sheet 9 even when using a reduced-diameter paddle member 50.

[0105] The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications are possible.

[0106] For example, in the above embodiment, an example has been described in which the sheet processing device 5 is installed in the body space 6 of the image forming apparatus 1. However, the sheet processing device 5 having the above-described configuration is not necessarily limited to being installed in the body space 6 of the image forming apparatus 1. For example, the sheet processing device 5 may be installed adjacent to the image forming apparatus 1 side by side.

[0107] In the above embodiment, an example has been described in which the control unit 8 provided in the sheet processing apparatus 5 controls the operation of the paddle member 50. However, this is not limiting, and for example, the control unit 8 of the sheet processing apparatus 5 may be configured to be integrated with the control unit 7 of the image forming apparatus 1. [Explanation of symbols]

[0108] 1. Image forming device 5. Sheet processing device 8 Control Unit 9 sheets 35 trays 37 Regulatory components 50 Paddle member 51 Rotating body 52 Finn 53 Retaining member R1 Fin forming section R2 Fin-free area

Claims

1. a tray for loading each sheet to be conveyed; a regulating member provided at one end of the tray; a paddle member that is provided on the tray so as to be able to rise and fall, and that rotates in contact with the conveyed sheet, thereby causing one end of the sheet to abut against the regulating member and align the sheet; a control unit that determines a height position of the paddle member above the tray based on the number of sheets stacked on the tray and sheet information of the sheets to be conveyed, and controls the height position of the paddle member; A sheet processing apparatus comprising:

2. 2. The sheet processing apparatus according to claim 1, wherein the control unit changes the height position of the paddle member every time one sheet is conveyed.

3. The sheet information includes sheet thickness information, The sheet processing apparatus according to claim 1 , wherein the control unit determines the height position of the paddle member based on the number of sheets and the thickness information.

4. 4. The sheet processing apparatus according to claim 3, wherein the control unit determines a basis weight category of the sheet based on the thickness information, and determines the height position of the paddle member based on a representative value predetermined for the basis weight category.

5. The sheet information includes sheet size information, The sheet processing apparatus according to claim 3 , wherein the control unit corrects the determined height position of the paddle member based on the size information.

6. 6. The sheet processing apparatus according to claim 5, wherein when the sheet size indicated by the size information is larger than a predetermined size, the control unit corrects the height position of the paddle member to a lower position than the determined height position.

7. 4. The sheet processing apparatus according to claim 3, wherein the control unit corrects the determined height position of the paddle member in accordance with the state of image formation on the front and back sides of the sheet being conveyed.

8. 4. The sheet processing apparatus according to claim 3, wherein the control unit corrects the determined height position of the paddle member based on the amount of toner transferred onto the sheet being conveyed.

9. 4. The sheet processing apparatus according to claim 3, wherein the control unit acquires temperature information and humidity information, and corrects the determined height position of the paddle member based on the temperature information and the humidity information.

10. a holding member that holds the paddle member at a tip end and swings around a rotation shaft inserted into a base end to change the height position of the paddle member; a swing arm that engages with the tip of the holding member to swing the holding member; Equipped with 2. The sheet processing apparatus according to claim 1, wherein the control unit controls the height position of the paddle member by driving the swing arm to swing the holding member.

11. The sheet processing apparatus described in claim 1, characterized in that the paddle member has a rotating body and an elastic fin protruding outward from the outer peripheral surface of the rotating body, and by rotating the rotating body in a predetermined direction with the fin abutting against the sheet, the sheet is transported toward the regulating member and one end of the sheet is abutted against the regulating member.

12. The sheet processing apparatus according to claim 11, characterized in that the paddle member has a fin forming portion that contacts the fins with the sheet to apply a conveying force to the sheet as the rotating body rotates in the predetermined direction, and a fin non-forming portion that does not contact the fins with the sheet and does not apply a conveying force to the sheet.

13. 13. The sheet processing apparatus according to claim 12, wherein the fin forming portion has a plurality of fins formed at predetermined intervals, and when any one of the plurality of fins abuts against a sheet and elastically deforms, it does not interfere with other adjacent fins.

14. 2. The sheet processing apparatus according to claim 1, wherein the control unit raises the paddle member when the sheet is conveyed toward the regulating member by rotating the paddle member at the determined height position.

15. an image forming apparatus that conveys a sheet and forms an image on the sheet while being conveyed; a sheet processing apparatus according to any one of claims 1 to 14; Equipped with The image forming system is characterized in that the sheet processing apparatus receives a sheet on which an image has been formed in the image forming apparatus, and aligns the sheet by abutting one edge of the sheet against the regulating member on the tray.

16. 16. The image forming system according to claim 15, wherein the sheet processing apparatus is mounted on a body of the image forming apparatus.

17. a tray for loading each sheet to be conveyed; a regulating member provided at one end of the tray; a paddle member that is provided on the tray so as to be able to rise and fall, and that rotates in contact with the conveyed sheet, thereby causing one end of the sheet to abut against the regulating member and align the sheet; A control method for a sheet processing apparatus comprising: A control method characterized by determining the height position of the paddle member on the tray based on the number of sheets loaded on the tray and sheet information of the sheets to be transported, and controlling the height position of the paddle member.

Images