Sheet processing apparatus and image forming apparatus

Abstract

To provide a sheet processing device capable of performing folding processing with high positional accuracy and an image forming device having the same.SOLUTION: A shielding member 300 movable to a shielding position and a retreated position is provided to a sheet folding unit 200 for folding a sheet S. The shielding member 300 is retreated to the retreated position in a resist correction time to allow a resist loop of the sheet S to curve outward to a resist loop space 341, to prevent inclination of a folding position of the sheet S. In a first folding time, when making the folding loop of the sheet S curve outward to a folding loop space 342, the resist loop space 341 is shielded not to allow the other part of the sheet S to enter the resist loop space 341, to improve accuracy of the folding position.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a sheet processing apparatus and an image forming apparatus, and more particularly to a technique for preventing the occurrence of skew during a sheet folding process and improving the accuracy of the folding position during the folding process. [Background technology]

[0002] The sheet processing device performs folding processes such as folding in half or Z-folding, punching holes, and stapling on printed materials output by an image forming device or sheets supplied from a tray or the like.

[0003] Of these processes, for example, folding is not necessarily performed every time the image forming apparatus outputs a printed material, so a post-processing device has been disclosed that includes, as shown in Fig. 22, a pair of conveying rollers 2201, a pair of folding rollers 2203 that performs a first folding process for folding in half, a pair of folding rollers 2202 that performs a second folding process for Z-folding after the first folding process, and a guide member 2206 that prevents contact with nip 22N3 of pair of folding rollers 2203 (see Patent Document 1). This guide member 2206 is used to guide the leading edge of paper that is not to be folded or paper before the first fold is formed into nip 22N2 of pair of folding rollers 2202, so that these do not accidentally move toward pair of folding rollers 2203 and cause paper jams, achieving good paper feed efficiency.

[0004] Furthermore, when performing folding processing, it is important to improve the accuracy of the folding position. For this reason, as shown in Fig. 23, a sheet folding device C has been disclosed that includes a conveyance path 2342 for conveying a sheet, a feed roller 2333, a pair of folding rollers 2334 arranged downstream of the feed roller 2333, a space 2350 provided below the conveyance path 2342 so as to allow the sheet to hang down from the conveyance path 2342 upstream of the pair of folding rollers 2334, a pushing member 2335 that can push against a predetermined position on the sheet hanging down into the space 2350 and move to a pushing position toward the pair of folding rollers 2334, and a guide unit 2345 that guides the conveyed sheet on the upstream side of the space 2350 in the conveyance direction (see Patent Document 2). The pushing member 2335 is arranged to push against the sheet hanging down into the space 2350 near the downstream end of the guide unit 2345 in the conveyance direction.

[0005] With this configuration, it is possible to reduce deviations and variations in the folding position even if the degree of sagging, or curvature, of the sheet varies depending on the stiffness and other characteristics of the sheet and the amount of feed from the feed roller 2333. Therefore, it is possible to improve the positional accuracy of the folds formed on the sheet. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-128411 [Patent Document 2] Japanese Patent Publication No. 2020-093856 Summary of the Invention [Problem to be solved by the invention]

[0007] In the first of the above conventional technologies, a folding roller pair 2203 is disposed at a position separated from the conveying path 22TR1 on the way from the conveying roller pair 2201 to the folding roller pair 2202, and in order to transport the sheet for folding processing along the conveying path 22TR2 to the folding roller pair 2203, an opening 2207a is provided in a paper guide 2207 that guides the sheet along the conveying path 22TR1.

[0008] Guide member 2206 blocks opening 2207a, thereby preventing the sheet from moving toward pair of folding rollers 2203. For this reason, the sheet conveyed along conveyance path 22TR1 does not have a constant state of sliding against paper guide 2207 and guide member 2206, which may cause the sheet to become skewed before reaching pair of folding rollers 2202.

[0009] Furthermore, in the second conventional technique, in order to facilitate the sheet hanging down into space 2350 on conveyance path 2342 from feed roller 2333 to pair of folding rollers 2334, lower conveyance guide 2346 that guides the sheet along conveyance path 2342 is divided into first lower guide portion 2346a and second lower guide portion 2346b. When conveying the sheet from feed roller 2333 to pair of folding rollers 2334, pusher member 2335 advances between first lower guide portion 2346a and second lower guide portion 2346b to prevent the sheet from hanging down into space 2350.

[0010] In this case as well, the state of friction between the sheet and the lower conveying guide 2346 or the pushing member 2335 is not constant, so there is a risk that the sheet may become skewed before it reaches the folding rollers 2334.

[0011] However, neither of the conventional techniques performs registration correction, and therefore, if the folding process is performed without correcting the skew of the sheet, the accuracy of the folding position will decrease.

[0012] On the other hand, if a registration loop space is provided on conveying path 22TR1 or conveying path 2342 to perform registration correction, there is a risk that part of the sheet will enter the registration loop space when the sheet is conveyed to folding roller pair 2203 or space 2350 for folding processing. In this case, the length of the sheet that enters the registration loop space will not be constant, so even if the skew of the sheet can be corrected, the deterioration in the accuracy of the folding position cannot be eliminated.

[0013] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a sheet processing device that can perform folding processing with high positional accuracy, and an image forming device equipped with the same. [Means for solving the problem]

[0014] In order to achieve the above object, a sheet processing apparatus according to one embodiment of the present disclosure is characterized by comprising: a first pair of rollers that transport a sheet along a transport path; a second pair of rollers arranged downstream of the first pair of rollers in the sheet transport direction; a first space that receives a first loop portion of the sheet during registration correction when the second pair of rollers is stopped; a third pair of rollers that folds the sheet at a fold position downstream of the first pair of rollers and upstream of the second pair of rollers after registration correction; a second space that receives a second loop portion of the sheet formed for folding processing by the third pair of rollers; a shielding member that is movable between a shielding position that blocks the sheet from entering the first space and a retracted position that does not provide said shielding; and a control means that moves the shielding member to the retracted position during registration correction and to the shielding position during folding processing.

[0015] The sheet conveying device further includes a first roller pair that conveys the sheet along a conveying path, a second roller pair that is disposed downstream of the first roller pair in the sheet conveying direction and is used for registration correction, a third roller pair that is used for folding the sheet after registration correction, and a second space that receives a second loop portion of the sheet that bends toward the third roller pair during folding. ,of The second space also serves as a first space for receiving the first loop portion of the sheet during registration correction. and a shielding section that is movable between a shielding position that shields the sheet from entering the second space and a retracted position that does not shield the sheet, and that guides the sheet to the second roller pair at the shielding position; and a control means that moves the shielding section to the shielding position when conveying the sheet and to the retracted position when performing registration correction and folding processing. It is characterized by:

[0016] In this case, the device may include a second shielding member that can be moved between a shielding position that blocks the entry of sheets into the second space and a retracted position that does not provide such shielding, and a second control means that moves the second shielding member to the shielding position during registration correction and to the retracted position during folding processing.

[0017] The second shielding member may move in conjunction with the shielding member.

[0018] The shielding member may also serve as the second shielding member, and the control means may also serve as the second control means.

[0019] The second roller pair and the third roller pair may share one roller.

[0020] The second roller pair may be used for a second folding process that is performed after the folding process using the third roller pair.

[0021] The first space may be located on the opposite side of the transport path from the second space.

[0022] The first space may be located on the same side as the second space with respect to the transport path.

[0023] The registration correction may be performed by causing the first roller pair to transport the sheet while the second roller pair is stopped from rotating, and forming a first loop portion on the sheet.

[0024] The folding process may also be performed by having the first roller pair transport the sheet faster than the second roller pair, causing the second loop portion formed in the sheet to bend toward the third roller pair.

[0025] Furthermore, prior to the sheet being bent out, after the resist correction, the second roller pair may be rotated faster than the first roller pair, or the first roller pair may be stopped while the second roller pair is rotating, thereby eliminating the loop at the first loop location formed by the resist correction.

[0026] In addition, an image forming apparatus according to one embodiment of the present disclosure includes an image forming unit that forms an image on a sheet, and a sheet processing device according to one embodiment of the present disclosure, and is characterized in that the sheet processing device processes the sheet on which the image has been formed in the image forming unit. [Effects of the Invention]

[0027] In this way, the first space is provided to receive the looped portion of the sheet and perform registration correction, so that the skew of the sheet can be corrected and the folding position of the sheet can be prevented from being tilted. Also, during folding processing, the sheet is shielded by the shielding member to prevent it from bending into the first space, so the amount of bending of the looped portion of the sheet into the second space can be stabilized and the accuracy of the folding position of the sheet can be improved. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is an external perspective view showing the main configuration of an image forming apparatus 1. FIG. [Figure 2] FIG. 2 is an external perspective view showing the main components of the sheet processing unit 100. [Figure 3] 1A and 1B are schematic diagrams illustrating the operating state of the sheet processing unit 100 when Z-folding a sheet S, where FIG. 1A shows the operating state during sheet conveyance, and FIG. 1B shows the operating state during registration correction. [Figure 4] 10A and 10B are schematic diagrams illustrating the operating state of the sheet processing unit 100 when Z-folding the sheet S, where (a) shows the operation of shielding the resist loop space 341 during the first fold, and (b) shows the operation of forming the first fold loop 392 in the sheet S during the first fold. [Figure 5]10A and 10B are schematic diagrams illustrating the operating state of the sheet processing unit 100 when Z-folding the sheet S, where (a) shows the operation of clamping the first folding loop 392 in the folding nip 332 of the folding roller pair 330 during the first folding, and (b) shows the operation of forming the second folding loop during the second folding. [Figure 6] A schematic diagram illustrating the operating state of the sheet processing unit 100 when Z-folding the sheet S, where (a) shows the operation of clamping the second fold loop 393 into the resist nip 323 of the resist roller pair 320 during the second fold, and (b) shows the state after the Z-fold is completed. [Figure 7] 2 is a block diagram showing the main configuration of a sheet processing control unit 103 of the sheet processing unit 100. FIG. [Figure 8] 10 is a flowchart illustrating the operation of the sheet processing control unit 103 when Z-folding the sheet S. [Figure 9] 10A and 10B are schematic diagrams illustrating the operating state of a sheet folding unit 200 according to a modified example in which a registration loop space 341 is provided on the same side of the conveying path 370 as the folding loop 393, where (a) shows the operating state during sheet conveyance, and (b) shows the operating state during registration correction. [Figure 10] This is a schematic diagram illustrating the operating state of a sheet folding unit 200 according to a modified example in which the resist loop space 341 is provided on the same side of the conveying path 370 as the folding loop 393, and shows the operation of forming the first folding loop 392 in the sheet S with the resist loop space 341 shielded during the first folding. [Figure 11] 10A and 10B are schematic diagrams illustrating the operating state of a modified sheet folding unit 200 that is provided with a guide member 1100 that shields the folding loop space 342, where (a) shows the operating state in which the guide portion 1101 of the guide member 1100 shields the folding loop space 342 during sheet transport, and (b) shows the operating state in which the guide portion 1101 of the guide member 1100 shields the folding loop space 342 during registration correction. [Figure 12]This is a schematic diagram illustrating the operating state of a modified sheet folding unit 200 that is provided with a guide member 1100 that shields the folding loop space 342, and shows the operation of forming a first folding loop 392 in the sheet S with the folding loop space 342 open during the first folding. [Figure 13] 10A and 10B are schematic diagrams illustrating the operating state of a modified sheet folding unit 200 in which a stopper 1300 is fixed to a guide member 1100 that shields the folding loop space 342, where (a) shows the operating state in which the guide portion 1101 of the guide member 1100 shields the folding loop space 342 during sheet transport, and (b) shows the operating state in which the guide portion 1101 of the guide member 1100 shields the folding loop space 342 during registration correction. [Figure 14] This is a schematic diagram illustrating the operating state of a sheet folding unit 200 according to a modified example in which a stopper 1300 is fixed to a guide member 1100 that shields the folding loop space 342, and shows the operation of forming a first folding loop 392 in a sheet S when the shielding member 300 that shields the resist loop space 341 is fixed in a shielding position by the stopper 1300 during the first folding. [Figure 15] 10A and 10B are schematic diagrams illustrating the operating states of a modified sheet folding unit 200 that uses a shielding member 1500 that moves between a shielding position and a retracted position using a rack and pinion mechanism, where (a) shows the operating state in which the folding loop space 342 is shielded by the shielding portion 1501 of the shielding member 1500 during sheet transport, and (b) shows the operating state during registration correction. [Figure 16] This is a schematic diagram illustrating the operating state of a modified sheet folding unit 200 that uses a shielding member 1500 that moves between a shielding position and a retracted position using a rack and pinion mechanism, and shows the operation of forming a first folding loop 392 in the sheet S when the resist loop space 911 is shielded by the shielding portion 1501 of the shielding member 1500 during the first folding. [Figure 17]10A and 10B are schematic diagrams illustrating the operating state of a sheet folding unit 200 according to a modified example in which a loop space 1706 serves as both a registration loop space and a folding loop space, in which (a) shows the operation of the shielding member 1700 shielding the loop space 1706 during sheet transport, and (b) shows the operation of the shielding member 1700 retracting so that the registration loop 391 of the sheet S can be vented into the loop space 1706 during registration correction. [Figure 18] This is a schematic diagram illustrating the operating state of a sheet folding unit 200 according to a modified example in which the loop space 1706 serves as both a resist loop space and a folding loop space, and shows the operation of projecting the folding loop 393 of the sheet S into the loop space 1706 during the first folding operation with the shielding member 1700 retracted. [Figure 19] 10A and 10B are schematic diagrams illustrating the operating state of a sheet folding unit 200 according to a modified example that does not use a shielding member, where (a) shows the operation during sheet transport, and (b) shows the operation of projecting the registration loop 391 of the sheet S into the loop space 1903 during registration correction. [Figure 20] 19A and 19B are schematic diagrams illustrating the operation of the sheet folding unit 200 according to a modified example in which a shielding member is not used, and illustrate the operation of projecting the folding loop 392 of the sheet S into the loop space 1903 during the first folding. [Figure 21] 10 is a schematic diagram showing the main configuration of a sheet folding unit 200 in which a pair of registration rollers 320 and a pair of folding rollers 330 do not share a roller. FIG. [Figure 22] FIG. 1 is a schematic diagram showing the main configuration of a post-processing device according to a conventional technique. [Figure 23] FIG. 1 is a schematic diagram showing a main configuration of a sheet folding device according to a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a sheet processing apparatus and an image forming apparatus according to the present disclosure will be described with reference to the accompanying drawings. [1] Configuration of image forming device First, the configuration of the image forming apparatus according to this embodiment will be described.

[0030] As shown in Fig. 1, image forming apparatus 1 is a multi-function peripheral (MFP) that combines printing, copying, facsimile, and other functions, and includes an image reading unit 110, an image forming unit 120, a paper feed unit 130, an operation panel 140, and a sheet processing unit 100. Image reading unit 110 can read an original document using a so-called sheet-through method or a platen-set method to generate image data. Image forming unit 120 forms an image using image data generated by image reading unit 110 or image data specified in an image formation job received from another device (e.g., a personal computer) via a communication network (not shown), such as a LAN (Local Area Network) or the Internet.

[0031] The paper feed unit 130 supplies recording sheets that the image forming unit 120 uses to form an image. The operation panel 140 presents information to a user of the image forming apparatus 1 and accepts operation inputs from the user. This operation input includes a designation of whether or not sheet processing by the sheet processing unit 100 is required. If sheet processing by the sheet processing unit 100 is not required, the image forming unit 120 discharges the recording sheet on which the image has been formed onto the paper discharge tray 122. If sheet processing is required, the image forming unit 120 transports the recording sheet on which the image has been formed to the sheet processing unit 100.

[0032] The image forming unit 120 includes a main body control unit 121, which monitors and controls the operation of each unit of the image forming apparatus 1. When the user's operation input received by the operation panel 140 is an instruction for sheet processing, the main body control unit 121 notifies the sheet processing unit 100 of the content of the user's instruction before conveying the recording sheet to the sheet processing unit 100.

[0033] The sheet processing section 100 receives recording sheets from the image forming section 120 and processes the sheets. As shown in FIG. 2, the sheet processing section 100 includes a sheet folding unit 200, a sheet sensor 201, and a stapler unit 210. The sheet folding unit 200 folds the sheets conveyed from the image forming section 120. The sheet sensor 201 detects the recording sheets fed from the image forming section 120.

[0034] The stapler unit 210 also staples the sheets conveyed from the image forming unit 120. The sheet processing unit 100 may also perform sheet processing other than folding and stapling, such as punching. The sheet processing unit 100 discharges the processed sheets onto the discharge trays 101 and 102.

[0035] The sheet processing unit 100 also includes a sheet processing control unit 103. The sheet processing control unit 103 monitors and controls the operation of each unit of the sheet processing unit 100. The sheet processing unit 100 also receives a notification of a user instruction received by the main body control unit 121 of the image forming unit 120 from the operation panel 140. This notification includes, for example, the type of sheet processing specified by the user, and the sheet processing unit 100 executes the specified type of sheet processing. [2] Sheet processing unit 100 Next, the operation of the sheet processing section 100, particularly the operation of the sheet folding unit 200, will be described using Z-folding of a sheet as an example.

[0036] 3(a), the sheet folding unit 200 includes a pair of conveying rollers 310, a pair of registration rollers 320, and a pair of folding rollers 330. The pair of conveying rollers 310 is made up of conveying rollers 311 and 312. When the sheet sensor 201 detects the sheet S fed from the image forming unit 120, the conveying roller 311 starts to be rotated, and the conveying roller 312 rotates in response to the conveying roller 311. As a result, the sheet S is conveyed in the direction of arrow C along the conveying path 370.

[0037] The sheet folding unit 200 includes a conveying motor 381 that rotates and drives the conveying rollers 311. In addition, a conveying clutch 382 transmits the rotational driving force generated by the conveying motor 381 to the conveying rollers 311 or blocks the transmission of the rotational driving force to the conveying rollers 311. The conveying motor 381 and the conveying clutch 382 operate under the control of the sheet processing control unit 103.

[0038] The pair of registration rollers 320 is composed of a shared roller 321 and a registration roller 322 that are shared with the pair of folding rollers 330, and is used for registration correction (skew correction) in addition to conveying the sheet S. The pair of folding rollers 330 is composed of a shared roller 321 and a folding roller 331, and is used for folding the sheet S.

[0039] The sheet folding unit 200 includes a shared motor 383 that drives and rotates the shared roller 321. When the shared motor 383 drives and rotates the shared roller 321, the registration roller 322 and the folding roller 331 rotate in response to the rotation of the shared roller 321. The shared motor 383 operates under the control of the sheet processing control unit 103.

[0040] Conveyance guide members 351 , 352 , 353 and 354 guide the sheet along a conveyance path 370 from the conveyance roller pair 310 to the registration roller pair 320 .

[0041] A resist loop space 341 is provided on the conveying path 370 from the conveying roller pair 310 to the resist roller pair 320 to allow the loop portion (resist loop) 391 (Figure 3(b)) of the sheet S to be bent out when the sheet S is subjected to resist correction.

[0042] The shielding member 300 can swing up and down at its upstream end in the sheet conveying direction around a swing shaft 301 located at its downstream end in the sheet conveying direction. Under the control of the sheet processing control unit 103, the shielding member 300 is driven to swing by a shielding member drive motor 384, and can reciprocate between a shielding position (FIG. 3(a)) where the shielding member 300 blocks the sheet S from entering the registration loop space 341 and a retracted position (FIG. 3(b)) where the shielding member 300 does not block the sheet S from entering the registration loop space 341.

[0043] When the sheet S is folded, a loop portion (first fold loop) 392 ( FIG. 4( b) ) of the sheet S protrudes from the fold loop space 342, which is the space from the conveyance path 370 of the sheet S to the folding nip 332 of the folding roller pair 330. The folding process is performed by sandwiching the first fold loop 392 in the folding nip 332 of the folding roller pair 330. This folding process is the first folding process when the sheet S is Z-folded.

[0044] A sheet sensor 361 is disposed between the pair of transport rollers 310 and the pair of registration rollers 320 on a transport path 370 of the sheet S, and is capable of detecting the leading and trailing edges of the sheet S. In addition, a sheet sensor 362 is disposed downstream of the pair of registration rollers 320 on the transport path 370, and is also capable of detecting the leading and trailing edges of the sheet S. The sheet sensors 201, 361, and 362 may detect the sheet S optically or mechanically, and needless to say, the detection method is not limited.

[0045] As shown in FIG. 3(b), during registration correction of the sheet S, the conveying roller pair 310 conveys the sheet S, and the leading edge of the sheet S abuts against the registration nip 323 of the stopped registration roller pair 320, forming a registration loop 391. In this case, because the shielding member 300 is retracted to the retracted position, the registration loop 391 of the sheet S bends toward the registration loop space 341. In this way, the skew of the sheet S is corrected, and it is possible to prevent the folding position of the sheet S from becoming inclined compared to when registration correction is not performed. In this sense, it is possible to improve the accuracy of the folding position of the sheet S.

[0046] When folding the sheet S after the registration correction, as shown in Fig. 4(a), the pair of registration rollers 320 are rotationally driven to convey the sheet S along the conveying path 370. The pair of registration rollers 320 shares a common roller 321 with the pair of folding rollers 330, and the folding roller 331 also rotates in the direction of arrow H following the rotation of the common roller 321.

[0047] The sheet processing control unit 103 disengages the conveying clutch 382. In this way, the conveying roller pair 310 does not convey the sheet S, and therefore the registration loop 391 of the sheet S is gradually eliminated as the registration roller pair 320 conveys the sheet S. After the registration loop 391 of the sheet S is completely eliminated, the conveying roller pair 310 rotates in accordance with the movement of the sheet S.

[0048] When the sheet sensor 362 detects the leading edge of the sheet S, the sheet processing control unit 103 stops the rotation of the pair of registration rollers 320 and swings the shielding member 300 in the direction of arrow E toward the shielding position. This prevents the sheet S from entering the registration loop space 341 when the first folding loop 392 is formed, thereby improving the accuracy of the folding position of the sheet S compared to when the sheet S can enter the registration loop space 341.

[0049] It is also possible to slow the conveying speed of the conveying roller pair 310 to a speed that can eliminate the registration loop 391 without disengaging the conveying clutch 382. Alternatively, the conveying roller pair 310 may continue to convey the sheet S at the original speed. When a fold loop 392 is formed during folding, the shielding member 300 is moved to the shielding position to prevent the registration loop 391 from entering the registration loop space 341, and the registration loop 391 is absorbed by the fold loop 392.

[0050] 4(b), the sheet processing control unit 103 rotates the conveying roller pair 310 to convey the sheet S, and causes the first folding loop 392 of the sheet S to bend toward the folding nip 332 of the folding roller pair 330 within the folding loop space 342. When the leading portion of the first folding loop 392 of the sheet S in the bending direction is pressed against the common roller 321 and the folding roller 331, the sheet processing control unit 103 rotates the folding roller pair 330 to sandwich the first folding loop 392 of the sheet S in the folding nip 332, thereby folding the sheet S in half so that the leading portion becomes a crease.

[0051] The pair of folding rollers 330 continues to rotate, and as shown in Fig. 5(a), conveys the sheet S that has been folded the first time in the direction of arrow L. When the sheet S has been conveyed by the conveyance amount that matches the second folding position, the sheet processing control unit 103 stops the rotational driving of the pair of folding rollers 330. Thereafter, the sheet processing control unit 103 starts the rotational driving of the pair of conveying rollers 310, and conveys the sheet S along the conveying path.

[0052] 5(b), a loop portion (second fold loop) 393 is formed in the sheet S. As the conveying roller pair 310 conveys the sheet S, the second fold loop 393 bends toward the registration nip 323 of the registration roller pair 320 within the fold loop space 342. The second fold loop 393 of the sheet S is finally pressed against the shared roller 321 and the registration roller 321.

[0053] When the sheet processing control unit 103 drives and rotates the pair of registration rollers 320 while the second folding loop 393 is pressed against the shared roller 321 and the registration roller 321, the second folding loop 393 is sandwiched in the registration nip 323, and the sheet S is folded, as shown in FIG. 6(a). At this time, the leading edge of the sheet S also passes through the registration nip 323.

[0054] Concurrently, portion 394 of sheet S folded in the first process is conveyed in the direction of arrow M by folding roller pair 330, passes through folding nip 332, and heads toward registration nip 323. As shown in FIG. 6(b), portion 394 folded in the first folding process that has passed registration nip 323 is further conveyed in the direction of arrow N. Sheet S is conveyed in the direction of arrow N, and finally, the trailing edge of sheet S leaves registration nip 323, completing the Z-folding of sheet S. [3] Configuration of the sheet processing control unit 103 Next, the configuration of the sheet processing control unit 103 will be described.

[0055] 7, the sheet processing control unit 103 includes a CPU (Central Processing Unit) 701, a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, and a timer 704. The CPU 701, ROM 702, RAM 703, and timer 704 are connected via an internal bus 705 so as to be able to exchange data with one another.

[0056] When the image forming apparatus 1 is reset, for example, by being powered on, the CPU 701 reads and starts a boot program from the ROM 702, and executes the control program read from the ROM 702, using the RAM 703 as a working storage area. When executing the control program, the CPU 701 also sets a time in a timer 704, and receives a notification when the set time has elapsed.

[0057] By executing a control program, the CPU 701 controls the operation of the conveying motor 381, conveying clutch 382, ​​shared motor 383, and shielding member drive motor 384, sets a timer 704, and refers to the detection signals of the sheet sensors 201, 312, and 313.

[0058] The sheet processing control unit 103 is also connected to the main body control unit 121, and receives instruction commands and notifications from the main body control unit 121 and notifies the main body control unit 121 of the status of the sheet processing unit 100. The main body control unit 121 monitors and controls the operations of the image reading unit 110, the image forming unit 120, the paper feeding unit 130, and the operation panel 140. [4] Operation of the sheet processing control unit 103 The operation of the sheet processing control unit 103 will be described using the operation at the time of Z-folding as an example. It is assumed that the sheet processing control unit 103 has received an instruction from the main body control unit 121 of the image forming apparatus 1 to perform Z-folding on the sheet in advance.

[0059] 8, when the sheet sensor 201 detects the leading edge of the sheet and thereby detects that a sheet has been conveyed from the image forming unit 120 (S801: YES), the sheet processing control unit 103 starts driving the conveyance motor 381 (S802) and connects the conveyance clutch 382 (S803). This causes the conveyance roller pair 310 to rotate, and the sheet received from the image forming unit 120 is conveyed. Note that a time suitable for forming a registration loop 391 with a loop amount required for registration correction is set in advance as time T1.

[0060] Next, when the sheet sensor 361 detects the leading edge of the sheet (S811: YES), the sheet processing control unit 103 drives the shielding member drive motor 384 to swing the shielding member 300 to the retracted position (S812), and sets a time T1 in the timer 704. By conveying the sheet S by the conveying roller pair 310 for the time T1, a registration loop 391 is formed in the sheet S, and the skew is corrected.

[0061] If a timeout occurs in the timer 704 (S821: YES), the conveying clutch 382 is disengaged (S822), the transmission of rotational driving force from the conveying motor 381 to the conveying roller 311 is stopped, and the rotational driving of the conveying motor 381 is stopped (S823). After that, the common motor 383 starts to rotate in the forward direction (S824). This causes the common roller 321 to rotate in the forward direction of arrow G shown in FIG. 4(a), and the sheet S is conveyed toward the sheet sensor 362.

[0062] When the sheet sensor 362 detects the leading edge of the sheet S (S831: YES), the rotation of the shared motor 383 is stopped (S832). As a result, the sheet S is sandwiched in the registration nip 323 of the registration roller pair 320. Next, the shielding member drive motor 384 is driven to swing the shielding member 300 from the retracted position to the shielding position (S833), and the timer 704 is set to time T2.

[0063] Time T2 is preset as the time required for the first folding loop 392 of the sheet S to come into contact with the pair of folding rollers 330 and for the pair of folding rollers 330 to rotate and for the first folding loop 392 of the sheet S to be sandwiched in the folding nip 332.

[0064] Thereafter, the driving of the conveying motor 381 is started (S834), and the conveying clutch 382 is engaged (S835). As a result, when the sheet S is conveyed by the conveying roller pair 310 for a time T2, a first folding loop 392 is formed in the sheet S, the sheet S bends toward the folding nip 332 of the folding roller pair 330, and comes into contact with the shared roller 321 and the folding roller 331.

[0065] If the timer 704 times out (S841: YES), the conveying clutch 382 is disengaged (S842) and the rotation of the conveying motor 381 is stopped (S843). This stops the first folding loop 392 of the sheet S from entering the folding nip 332 of the folding roller pair 330. Next, the timer 704 is set to time T3 (S844).

[0066] Time T3 is set in accordance with the second folding position of sheet S. Thereafter, reverse rotation driving of shared motor 383 is started (S845). As a result, shared roller 321 rotates reversely in the direction of arrow J, and first folding loop 392 of sheet S is sandwiched in folding nip 332 of folding roller pair 330, thereby performing the first folding.

[0067] If a timeout occurs in the timer 704 (S851: YES), the reverse rotation of the shared motor 383 is stopped (S852). Thereafter, the rotation of the conveying motor 381 is started (S853), the conveying clutch 382 is engaged (S854), and a time T4 is set in the timer 704 (S855). As the conveying roller pair 310 conveys the sheet S for the time T4, a second fold loop 393 is formed in the sheet S, which then bends toward the registration nip 323 of the registration roller pair 320 and comes into contact with the shared roller 321 and the registration roller 321.

[0068] If the timer 704 times out (S861: YES), the conveying clutch 382 is disengaged (S862), and the rotation of the conveying motor 381 is stopped (S863). Thereafter, the forward rotation of the shared motor 383 is started (S864). As a result, the second folding loop 393 of the sheet S is sandwiched in the registration nip 323 of the registration roller pair 320, and the second folding is performed.

[0069] Thereafter, when the sheet sensor 362 detects the rear end of the sheet S (S871: YES), the forward rotation of the shared motor 383 is stopped (S872).

[0070] In this way, even when a registration correction is performed on the sheet S to prevent the folding direction of the sheet S from tilting, the shielding member 300 blocks the sheet S from entering the registration loop space 341 when forming the first folding loop 392 and the second folding loop 393, thereby improving the positional accuracy of the first and second folds. [5] Variation While the present disclosure has been described above based on the embodiments, it goes without saying that the present disclosure is not limited to the above-described embodiments, and the following modifications may be implemented. Note that in this specification, common components are assigned common reference numerals. (5-1) In the above embodiment, the resist loop space 341 and the fold loop space 342 are provided on opposite sides of the conveying path 370. However, it goes without saying that the present disclosure is not limited to this. Alternatively, the resist loop space 341 and the fold loop space 342 may be provided on the same side of the conveying path 370.

[0071] 9(a), when the sheet S is conveyed, the shielding member 901 moves to the closed position to prevent the sheet S from entering the registration loop space 911. Furthermore, when the registration correction is performed, the shielding member 901 swings in the direction of arrow O around the swing shaft 902 as the swing center to move to the retracted position, as shown in FIG.

[0072] 10, during the first folding, the shielding member 901 swings in the direction of arrow P around the swing shaft 902 as the swing center and moves to the shielding position, preventing the resist loop 921 of the sheet S from entering the resist loop space 911. In this way, the accuracy of the folding position can be improved, as in the above embodiment. (5-2) In the above embodiment, an example was described in which a shielding member 300 is used to prevent the sheet S from entering the resist loop space 341, but it goes without saying that the present disclosure is not limited to this, and in addition, the following may also be used.

[0073] 11 and 12, in order to prevent the sheet S from entering the fold loop space 342 when the leading edge of the sheet S is conveyed to the registration nip 323 of the registration roller pair 320, a guide member 1100 may be provided to guide the sheet S to the registration nip 323. The guide member 1100 is made up of a guide portion 1101, an arm portion 1102, and a swing shaft 1103, and can swing in the direction of arrow Q with the swing shaft 1103 as the swing center.

[0074] 11(a), during sheet conveyance, the guide unit 1101 moves to the blocking position. This blocks the gap between the conveyance path 370 and the fold loop space 342 so that the sheet S does not deviate from the conveyance path 370 and enter the fold loop space 342. As shown in FIG. 11(b), during registration correction, the guide unit 1101 remains in the blocking position to prevent the sheet S from entering the fold loop space 342.

[0075] 12, during the first folding, the guide member 1100 swings in the direction of arrow Q around the swing shaft 1103, causing the guide portion 1101 to move from the shielding position to the retracted position. This allows the first fold loop 392 of the sheet S to be projected from the conveying path 370 into the fold loop space 342. Also during the second folding, the guide portion 1101 remains in the retracted position, allowing the second fold loop 393 of the sheet S to be projected from the conveying path 370 into the fold loop space 342.

[0076] In this way, the leading edge of the sheet S can be reliably conveyed to the registration nip 323, and it is possible to prevent the leading edge of the sheet S from entering the fold loop space 342 and causing a paper jam or the like. (5-3) In the above embodiment, an example was described in which the shielding member 300 is oscillated using the shielding member drive motor 384. However, it goes without saying that the present disclosure is not limited to this. Alternatively, the shielding member drive motor 384 may be omitted as follows.

[0077] 13(a), during sheet conveyance, the shielding member 300 is pivotally supported by a swing shaft 301 so as to be able to swing, and when not subjected to external force, the shielding member 300 is positioned at the shielding position due to its own weight. In addition, the guide portion 1101 of the guide member 1100 is also positioned at the shielding position, preventing the sheet S from entering the fold loop space 342 and guiding the sheet S to the registration nip 323.

[0078] 13(b), during registration correction, the sheet S is pushed up by the registration loop 391 formed on the sheet S, swings, and moves to the retracted position. In this case, the guide portion 1101 of the guide member 1100 remains in the blocking position, so the sheet S is blocked so as not to enter the folding loop space 342.

[0079] 14, at the time of the first folding, a drive unit (not shown) drives guide member 1100 to swing, causing guide member 1100 to swing in the direction of arrow Q. A stopper 1300 is fixed to guide member 1100. In addition, a rib 302 is provided upright on shielding member 300. When guide member 1100 swings in the direction of arrow Q and guide portion 1101 thereof moves to the retracted position, end face 1301 of stopper 1300 abuts against rib 302 of shielding member 300, thereby preventing shielding member 300 from swinging.

[0080] This allows the shielding member 300 to remain in the shielding position, preventing the sheet S from entering the registration loop space 341 during the first folding. This improves the accuracy of the folding position during the first folding. Furthermore, since the shielding member drive motor 384 is no longer necessary, the component costs and assembly costs of the sheet processing unit 100 can be reduced, and the sheet processing unit 100 can be made smaller and more space-saving. (5-4) Regarding a configuration in which the resist loop space 911 and the folding loop space 342 are on the same side of the conveying path 370, the above modified example has been described using an example in which the shielding member 901 is swung between the shielding position and the retracted position. However, it goes without saying that the present disclosure is not limited to this, and instead, the following may be used.

[0081] 15 and 16, the shielding member 1500 has a rack and pinion configuration, and a rack portion 1502 is provided on a shielding section 1501, which also serves as a guide member that guides the sheet S along the conveying path 370, and meshes with a pinion gear 1503. The pinion gear 1503 is rotated by a shielding member drive motor 1510, which causes the shielding section 1501 to move parallel to the conveying path 370.

[0082] 15(a), during sheet conveyance, a shielding portion 1501 shields the fold loop space 342 and guides the leading edge of the sheet S to the registration nip 323 of the registration roller pair 320. This prevents the sheet S from entering the fold loop space 342, thereby preventing the occurrence of paper jams, etc. In this case, the registration loop space 341 is not shielded.

[0083] 15(b), during registration correction, the shielding portion 1501 shields the fold loop space 342 and maintains a state in which it does not shield the registration loop space 911. As a result, the registration loop 1521 of the sheet S protrudes into the registration loop space 911, and the skew of the sheet S is corrected.

[0084] 16, during the first folding, the shielding member drive motor 1510 rotates and drives the pinion gear 1503 in the direction of the arrow R, thereby moving the shielding part 1501 in the direction of the arrow T. This uncovers the fold loop space 342, opening the fold loop space 342 while shielding the resist loop space 911.

[0085] Before the shielding portion 1501 is moved in the direction of the arrow T, the pair of registration rollers 320 conveys the sheet S and advances the leading edge of the sheet S to the detection position of the sheet sensor 362, thereby eliminating the registration loop 1521 of the sheet S. Therefore, the registration loop 1521 of the sheet S is not pinched by the shielding portion 1501.

[0086] After the shielding portion 1501 opens the fold loop space 342 , the pair of conveying rollers 310 conveys the sheet S, forming a fold loop 1522 in the sheet S, which then curves out toward the folding nip 332 of the pair of folding rollers 330 .

[0087] Even in this case, the shielding member 1501 shields the resist loop space 911 so that the resist loop 1521 is not formed in the sheet S during folding processing, thereby improving the accuracy of the folding position of the sheet S. Furthermore, since the shielding member 1500 is moved along the conveying path 370 without swinging, only a small space is required to shield the resist loop space 911. This makes it easy to reduce the size of the sheet processing unit 100. (5-5) In the above embodiment, the resist loop space 341 and the fold loop space 342 are provided separately. However, it goes without saying that the present disclosure is not limited to this. Alternatively, the resist loop space 341 and the fold loop space 342 may share at least a portion of each other.

[0088] 17A, the sheet folding unit 200 according to this modification includes a pair of conveying rollers 310 and guide members 1701 and 1702, and guides the sheet fed by the pair of conveying rollers 310 in the direction of arrow C using the guide members 1701 and 1702. Because the guide members 1701 and 1702 are adjacent to each other across the conveyance path of the sheet S, there is insufficient space within the space between the guide members 1701 and 1702 to form a registration loop required for registration correction. The downstream end of the guide member 1702 in the sheet conveyance direction is located just before the loop space 1706.

[0089] The shielding member 1700 has a rack and pinion configuration, and a rack portion 1704 is provided on a shielding portion 1703, which also serves as a guide member for guiding the sheet S in the direction of arrow C, and meshes with a pinion gear 1705. The pinion gear 1705 is rotated by a shielding member drive motor 1710, which causes the shielding portion 1703 to move parallel to the direction of arrow C.

[0090] The shielding portion 1703 can move to a shielding position where it advances between the conveyance path of the sheet S and the loop space 1706 to block the loop space 1706 so as to prevent the sheet from entering the loop space 1706, and to a retracted position where it retreats from between the conveyance path of the sheet S and the loop space 1706 to release the shielding. During sheet conveyance, the shielding portion 1703 advances to the shielding position and guides the leading edge of the sheet S to the registration nip 323 of the registration roller pair 320.

[0091] 17(b), during registration correction, the shielding portion 1703 retreats from the shielding position to the retreated position, allowing the registration loop 391 of the sheet S to bend toward the loop space 1706. This corrects the skew of the sheet S. Therefore, it is possible to prevent the first folding position of the sheet S from being tilted.

[0092] 18, during the first folding, the shielding portion 1703 remains in the retracted position, allowing the folding loop 392 of the sheet S to bend toward the loop space 1706. This allows the first folding process of the sheet S to be performed. Furthermore, since the loop space 1706 serves as both the resist loop space and the folding loop space, and there is no space other than the loop space 1706 where the sheet S can form a loop, the accuracy of the first folding position can be improved. (5-6) In the above modified example, the case where the shielding member 1700 is provided in a configuration in which the loop space 1706 serves as both a resist loop space and a folding loop space has been described as an example. However, it goes without saying that the present disclosure is not limited to this, and the following may be used instead.

[0093] 19(a), the shielding member 1700 may be omitted from the sheet folding unit 200. During sheet transport, the leading edge of the sheet S sent out by the transport roller pair 310 is guided by guide members 1901 and 1902 to the registration nip 323 of the registration roller pair 320, in the same manner as in the above embodiment.

[0094] During registration correction, as shown in Fig. 19(b), registration loop 391 of sheet S is bent into loop space 1903, thereby correcting the skew of sheet S. During the first folding, as shown in Fig. 20, folding loop 392 of sheet S is bent into loop space 903, thereby performing the first folding process of sheet S.

[0095] In this way, the shielding member drive motor 1710 can also be omitted, so that the sheet processing section 100 can be made smaller, more space-saving, and less expensive. (5-7) In the above embodiment, the example was described in which the registration roller pair 320 and the folding roller pair 330 share the shared roller 321. However, it goes without saying that the present disclosure is not limited to this, and the following may be used instead.

[0096] 21, the pair of registration rollers 320 and the pair of folding rollers 330 do not need to share a roller. In this case, it is desirable to provide a guide member 2103 so that the sheet S does not get caught between roller 2101 of the pair of registration rollers 320 and roller 2102 of the pair of folding rollers 330 that faces roller 2101.

[0097] Also, Figure 21 shows a case where the folding roller pair 330 is arranged below the transport path of the sheet S, but depending on the device configuration of the sheet processing unit 100, there may be more space above the transport path of the sheet S than below, and in such cases, the folding roller pair 330 may be arranged above the transport path. (5-8) In the above embodiment, the image reading unit 110, the image forming unit 120, and the paper feeding unit 130 constitute a multifunction device. However, it goes without saying that the present disclosure is not limited to this. Even single-function devices such as a printer device, a copy device with a scanner, or even a facsimile device with a facsimile communication function can obtain the above-described effects by applying the present disclosure when combined with the sheet processing unit 100. [Industrial Applicability]

[0098] The sheet processing apparatus and image forming apparatus according to the present disclosure are useful as apparatuses capable of performing folding processing with high positional accuracy. [Explanation of symbols]

[0099] 1. Image forming device 100...................................................Sheet processing section 110...................................................................Image scanning unit 120...................................................................Image forming unit 130…………………………………………Paper feed section 200………………………………………Sheet folding unit 300, 901, 1500, 1700...Shielding member 310...................................................................Transport roller pair 320....................................................................Registration roller pair 330………………………………………Folding roller pair 341, 911……………………………Registration loop space 342………………………………………Fold loop space 391………………………………………Registration Loop 392………………………………………Fold loop 1100……………………………………Guide member 1300……………………………………Stopper 1706, 1903………………………Loop Space

Claims

1. a first roller pair that transports the sheet along a transport path; a second roller pair disposed downstream of the first roller pair in the sheet conveying direction; a first space for receiving a first loop portion of the sheet during registration correction with the second roller pair stopped; a third roller pair for folding the sheet at a folding position downstream of the first roller pair and upstream of the second roller pair after the registration correction; a second space for receiving a second loop portion of the sheet formed for folding by the third roller pair; a shielding member that is movable between a shielding position that shields the sheet from entering the first space and a retracted position that does not shield the sheet; and a control means for moving the shielding member to a retracted position during registration correction and to a shielding position during folding processing. A sheet processing apparatus characterized by:

2. a first roller pair that transports the sheet along a transport path; a second roller pair disposed downstream of the first roller pair in the sheet conveying direction and used for registration correction; a third roller pair used for folding the sheet after the registration correction; a second space for receiving a second loop portion of the sheet that curves toward the third roller pair during folding processing; The second space also serves as a first space for receiving the first loop portion of the sheet during registration correction, moreover, a shielding portion that is movable between a shielding position that shields the sheet from entering the second space and a retracted position that does not shield the sheet, and that guides the sheet to the second roller pair at the shielding position; and a control means for moving the shielding portion to a shielding position during sheet conveyance and to a retracted position during registration correction and folding processing. A sheet processing apparatus characterized by:

3. a second shielding member that is movable between a shielding position that shields the sheet from entering the second space and a retracted position that does not shield the sheet; and second control means for moving the second shielding member to a shielding position during registration correction and to a retracted position during folding processing.

2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

4. The second shielding member moves in conjunction with the shielding member.

4. The sheet processing apparatus according to claim 3, wherein the sheet processing apparatus is a sheet processing apparatus.

5. the shielding member also serves as the second shielding member, The control means also serves as the second control means.

4. The sheet processing apparatus according to claim 3, wherein the sheet processing apparatus is a sheet processing apparatus.

6. The second roller pair and the third roller pair share one roller.

6. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

7. The second roller pair is used for a second folding process that is performed after the folding process using the third roller pair.

7. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

8. The first space is located on the opposite side of the conveying path from the second space.

6. The sheet processing apparatus according to claim 1, wherein the sheet is conveyed to the conveying apparatus.

9. The first space is located on the same side as the second space with respect to the conveying path.

8. The sheet processing apparatus according to claim 1, wherein the sheet is conveyed to the processing apparatus via a conveying mechanism.

10. The registration correction is performed by causing the first roller pair to convey the sheet while the rotation of the second roller pair is stopped, and forming a first loop portion on the sheet.

10. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

11. The folding process is performed by the first roller pair conveying the sheet faster than the second roller pair, causing the second loop portion formed in the sheet to bend toward the third roller pair.

11. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

12. Prior to the sheet curvature, after the registration correction, the second roller pair is rotated at a higher speed than the first roller pair, or the first roller pair is stopped while the second roller pair is rotated, thereby eliminating the loop at the first loop portion formed by the registration correction. The sheet processing apparatus according to claim 11 .

13. an image forming unit that forms an image on a sheet; a sheet processing apparatus according to any one of claims 1 to 12, The sheet processing apparatus processes sheets on which images have been formed in an image forming unit. An image forming apparatus characterized by:

Images