Medium processing device, image forming device, and image forming system

Abstract

To provide a medium processing device that can correct misalignment of a leading edge of a sheet when using circulating transport in overlapping processing of multiple media.SOLUTION: There is provided a medium processing device including: conveying means disposed on a conveying path that conveys a medium from upstream to downstream; and circulating conveying means disposed on a circulating conveying path that branches off from the conveying path and returns the medium to the upstream side of the conveying path. At least one of conveying roller pairs disposed on the circulating conveying path constitutes a misalignment correction conveying roller pair that corrects misalignment of the multiple media caused by circulating conveyance on the circulating conveying path.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a media processing device, an image forming device, and an image forming system. [Background technology]

[0002] There are known media processing devices that perform post-processing, such as aligning sheets of sheet media (hereinafter referred to as "sheets") to form a stack of sheets, and folding the sheets. There are also known image forming devices that have the functionality of a media processing device and the functionality of forming images on sheets, and image forming systems that have the media processing device and image forming device housed in separate housings and that are configured to operate in conjunction with each other.

[0003] Furthermore, there is known a technique for correcting skew of sheets when stacking multiple sheets by abutting the leading edge (the leading side in the conveying direction) of each sheet against the nip of a conveying roller (see Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] When the technology disclosed in Patent Document 1 is applied to multiple sheets that are stacked using a circular transport operation, there is a problem in that it is difficult to deal with the fact that when the stacked sheets are transported in a circular manner, the leading edges of each sheet may shift again due to differences in the internal and external paths within the transport path.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a media processing device that can correct misalignment of the leading edge of a sheet when circulating transport is used in the overlapping process of a plurality of media. [Means for solving the problem]

[0006] In order to solve the above technical problems, one aspect of the present invention relates to a media processing device comprising: a conveying means arranged on a conveying path that conveys media from upstream to downstream; and a circulating conveying means arranged on a circulating conveying path that branches off from the conveying path and returns the media to the upstream side of the conveying path, wherein at least one of the plurality of conveying roller pairs arranged on the circulating conveying path constitutes a misalignment correction conveying roller pair that corrects overlapping misalignment of multiple media caused by circulating conveyance on the circulating conveying path. [Effects of the Invention]

[0007] According to the present invention, it is possible to correct misalignment of the leading edge of a sheet when circulating transport is used in the overlapping process of a plurality of media. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view showing an embodiment of an image forming apparatus including a media processing device according to the present invention. [Figure 2] 1 is a diagram showing a schematic configuration of an embodiment of an image forming system according to the present invention. [Figure 3] FIG. 2 is a block diagram showing an example of a control configuration according to the embodiment. [Figure 4] FIG. 2 is a diagram showing the internal configuration of a folding unit as an embodiment of the media processing device according to the present invention. [Figure 5] 5A to 5C are diagrams showing examples of folding that can be performed in the folding processing unit. [Figure 6] 10A to 10C are diagrams illustrating an example of a folding and conveying operation in the folding processing unit. [Figure 7] 10A and 10B are diagrams illustrating another example of the folding and conveying operation in the folding processing unit. [Figure 8] 10A and 10B are diagrams illustrating another example of the folding and conveying operation in the folding processing unit. [Figure 9] 10A and 10B are diagrams illustrating another example of the folding and conveying operation in the folding processing unit. [Figure 10] 10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. [Figure 11]10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. [Figure 12] 10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. [Figure 13] 10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. [Figure 14] 10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. [Figure 15] 10 is an enlarged view of the internal configuration showing one step of the folding and conveying operation in the folding processing unit. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment of Image Forming Apparatus] First, an embodiment of an image forming apparatus according to the present invention will be described. Fig. 1 is an external view of the image forming apparatus 1. The image forming apparatus 1 according to this embodiment includes an image forming unit 100 as an image forming section, and a folding processing unit 200 that functions as a medium processing section. The folding processing unit 200 is a unit that cooperates with the image forming unit 100. Note that Fig. 1 illustrates an internal discharge type image forming unit 100. The image forming unit 100 has a function that enables the folding processing unit 200 to be selected as a discharge destination for a medium on which an image has been formed.

[0010] The folding processing unit 200 as an embodiment of the media processing device according to the present invention has the function of stacking multiple sheets P, which are sheet-like media, to form a sheet bundle Q. As will be described later, the folding processing unit 200 has the function of circulating and transporting the sheets P to stack multiple sheets and then folding them to form the sheet bundle Q. The internal configuration of the folding processing unit 200 for performing these functions will be described later.

[0011] [Embodiment of Image Forming System] 2 is a diagram showing a schematic configuration of an image forming system 1a according to an embodiment of the present invention. The image forming system 1a according to this embodiment is configured by connecting an image forming apparatus 100a and a folding processing apparatus 200a as a media processing apparatus. The image forming system 1a operates such that a sheet P on which an image has been formed by the image forming apparatus 100a is transported to the folding processing apparatus 200a, and a predetermined overlapping folding process is performed in the folding processing apparatus 200a.

[0012] [Control block functional configuration] Next, an embodiment of a control block that controls the operation of the image forming unit 100 and the folding processing unit 200 as a media processing device according to this embodiment will be described with reference to Figure 3. As shown in Figure 3, the image forming unit 100 includes a printer control unit 110 as a control block. The printer control unit 110 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, and a serial I / F 114.

[0013] The printer control unit 110 is connected to an image creation unit 120, an image reading unit 130, and an operation display unit 140. The image creation unit 120, the image reading unit 130, and the operation display unit 140 each include components for performing their respective functions. Each component included in the image creation unit 120, the image reading unit 130, and the operation display unit 140 operates based on a control signal from the printer control unit 110.

[0014] The image creation unit 120 is configured to perform image formation processing based on image data on a sheet P, which is a sheet-like recording medium. The image reading unit 130 is configured to acquire image data by reading an image formed on the sheet P. The operation display unit 140 has a function of serving both as an input unit for inputting operating conditions for the image creation unit 120 and the image reading unit 130, and as a display unit for displaying operation results, etc.

[0015] The operation display unit 140 also has a function of both displaying the processing contents in the sheet processing control unit 210 and inputting information for inputting setting information for controlling the operation (behavior) of the folding processing unit 200.

[0016] Control programs for controlling the image creation unit 120, the image reading unit 130, and the operation display unit 140 are stored in the ROM 112. The CPU 111 reads out the control programs stored in the ROM 112 and loads them into the RAM 113. The CPU 111 then stores data necessary for control in the RAM 113 and executes the control defined by the control programs while using the RAM 113 as a work area.

[0017] 3, the folding processing unit 200 includes a sheet processing control unit 210 as a control block. The sheet processing control unit 210 includes a CPU 211, a ROM 212, a RAM 213, and a serial I / F 214.

[0018] The sheet processing control unit 210 is connected to various loads 220 and various sensors 240. The various loads 220 include roller pairs, which will be described later. The roller pairs corresponding to the various loads 220 respectively constitute a conveying roller pair, a leading edge alignment conveying roller pair, a misalignment correction conveying roller pair, and a folding roller pair. The various loads 220 are operated by a drive motor that rotates at least one of the rollers constituting each roller pair. The drive motor constituting the various loads 220 is operated by a driver 230 that receives instructions from the sheet processing control unit 210. The various loads 220 are configured to perform operations including conveying control of the sheet P as a recording medium, overlapping conveying control of the sheet P, and folding processing of the sheet P.

[0019] The various sensors 240 are sheet detection units that detect the position of the sheet P in the conveyance path. A plurality of the various sensors 240 are arranged along the paths for conveyance and circulatory conveyance. In order to detect the conveyance amount and position of the sheet P and sheet stack Q to be processed, the various sensors 240 output signals to the sheet processing control unit 210 when they detect these. Based on the detection signals from the various sensors 240, the sheet processing control unit 210 determines the positions of the sheet P and sheet stack Q using a predetermined control program and controls the execution of appropriate processes. The position of the sheet P is calculated by the sheet processing control unit 210 based on the conveyance amount (conveyance distance) of the sheet P after the leading edge of the sheet P is detected by the sheet detection unit, based on the operation amount of the various loads 220.

[0020] A control program for the sheet processing control unit 210 to execute predetermined processing functions is stored in the ROM 212. The CPU 211 reads out the control program stored in the ROM 212 and loads it in the RAM 213. The CPU 211 then stores data necessary for control in the RAM 213 and executes control of the folding operation defined by the control program while using the RAM 213 as a work area. As described above, the sheet processing control unit 210 executes the control program stored in the ROM 212, thereby enabling detection of the sheet P and control of the conveyance of the sheet P, which will be described later.

[0021] The printer control unit 110 provided in the image forming unit 100 and the sheet processing control unit 210 provided in the folding processing unit 200 are communicatively connected via serial I / F 114 and serial I / F 214. This communication path is used to exchange control commands and information necessary for controlling the conveyance of the recording medium. The folding processing unit 200 switches between conveyance control of the recording medium, presence / absence of folding processing, and the type of folding processing, based on the control commands and information about the sheet P sent from the image forming unit 100, and information about the position of the recording medium obtained from various sensors 240.

[0022] The information about the sheet P sent from the image forming unit 100 (printer control unit 110) to the folding processing unit 200 (sheet processing control unit 210) includes a plurality of pieces of information. For example, it includes a plurality of pieces of sheet type information indicating the type of sheet P to be passed from the image forming unit 100 to the folding processing unit 200, the thickness of the sheet P, the size of the sheet P, etc. The information about the sheet P also includes information indicating the type of post-processing (such as whether to perform folding or overlap folding), information indicating the number of sheets P that make up a bundle in overlap folding, and information indicating the folding position when performing folding. The control command notified from the printer control unit 110 to the sheet processing control unit 210 also includes information indicating whether the passed sheet P corresponds to the last page (final sheet) of a unit to be processed collectively, i.e., a command equivalent to a "multiple-fold start notification."

[0023] [Embodiment of a media processing device] Next, the internal configuration of a folding processing unit 200 will be described as a first embodiment of a post-processing device according to the present invention. FIG. 4 is a schematic diagram illustrating the internal configuration of the folding processing unit 200. The folding processing unit 200 of this embodiment includes a through-conveying path W1 for conveying a sheet P discharged from the image forming unit 100 to a downstream post-processing device 3 without folding the sheet P. The folding processing unit 200 also includes a branched conveying path W2 branching from the through-conveying path W1 for folding the sheet P discharged from the image forming unit 100 and conveying the sheet P to the downstream post-processing device 3. The folding processing unit 200 also includes a circulating conveying path W3 branching from the through-conveying path W1 and serving as a receiving section for temporarily holding a sheet conveyed via a skew correction roller pair 11, a roller pair consisting of a first folding roller 12 and a first forward / reverse rotation roller 13, and a second forward / reverse rotation roller pair 16, and for conveying the sheet so that the sheet is superimposed on the subsequent sheet discharged from the image forming unit 100.

[0024] A pair of carry-in rollers 10 is disposed at the entrance side of the through-conveyance path W1 that receives the sheet P discharged from the image forming unit 100. The pair of carry-in rollers 10 is composed of a pressure roller 10a, which is a rotating member, and a drive roller 10b, which is an opposing member, and the drive roller 10b is driven to rotate by the driving force of a carry-in motor 10m, which is a drive source.

[0025] Further, a skew correction roller pair 11 serving as a leading edge alignment conveying roller pair, which is a first conveying means, is disposed downstream of the carry-in roller pair 10 on the through conveying path W1. The skew correction roller pair 11 is composed of a pressure roller 11a which is a rotating member and a drive roller 11b which is an opposing member, and the drive roller 11b is driven to rotate by the driving force of a skew forward / reverse motor 11m which is a drive source and can rotate forward and backward.

[0026] Further, at the exit side of the through conveyance path W1, there are provided a first folding roller 12, a first forward / reverse rotation roller 13 arranged in contact with the first folding roller 12, and a pressing roller 14 arranged in contact with the first forward / reverse rotation roller 13. By passing through the nip between the first folding roller 12 and the first forward / reverse rotation roller 13, the sheet P can move from the through conveyance path W1 to the branch conveyance path W2.

[0027] Furthermore, by passing through the nip between the first forward / reverse rotation roller 13 and the pressing roller 14, the sheet P can be conveyed to the downstream post-processing device 3 via the through conveyance path W1. Furthermore, in this embodiment, a second folding roller 15 arranged in contact with the first forward / reverse rotation roller 13 is provided on the outlet side of the branch conveyance path W2. Also, a second forward / reverse rotation roller pair 16 is provided on the branch conveyance path W2 on the opposite side of the second folding roller 15, across the nip between the first folding roller 12 and the first forward / reverse rotation roller 13, into which the sheet P enters from the through conveyance path W1. The second forward / reverse rotation roller pair 16 is made up of a pressing roller 16a which is a rotating member and a drive roller 16b which is an opposing member, and the drive roller 16b is rotationally driven by the driving force of a second forward / reverse rotation motor 16m which is a drive source.

[0028] First forward / reverse rotation roller 13 can be rotated forward and backward by the driving force of first forward / reverse rotation motor 13m. First folding roller 12, pressing roller 14, and second folding roller 15, which are arranged in contact with first forward / reverse rotation roller 13, are all driven rollers that rotate in accordance with the rotation of first forward / reverse rotation roller 13.

[0029] The drive roller 16b constituting the second forward / reverse rotation roller pair 16 can be driven to rotate forward and reverse by the driving force of a second forward / reverse rotation motor 16m which can rotate forward and reverse. The pressure roller 16a constituting the second forward / reverse rotation roller pair 16 is a driven roller which rotates in accordance with the rotation of the drive roller 16b.

[0030] Furthermore, in this embodiment, a second skew correction roller pair 17 is arranged on the circulating conveying path W3 as a misalignment correction conveying roller pair. The second skew correction roller pair 17 is composed of a pressure roller 17a which is a rotating member and a drive roller 17b which is an opposing member, and the drive roller 17b is driven to rotate by the driving force of a second skew correction motor 17m which is a drive source.

[0031] Further, at the branching point between the circulation transport path W3 and the through transport path W1, a film member 18 is provided, with the leading end of this film member 18 being provided on the through transport path W1 side.

[0032] In this embodiment, the roller shafts of all the driven rollers are biased by pressure springs 10s, 11s, 12s, 14s, 15s, 16s, and 17s, which serve as biasing means, so that a nip is formed between the opposing rollers.

[0033] Furthermore, in this embodiment, an entrance sensor 24 is provided as a sheet edge detection means for detecting the edge of the sheet P on the upstream side (the entrance side of the through conveying path W1) of the carry-in roller pair 10 in the sheet conveying direction. When the leading edge or trailing edge of the sheet P conveyed from the image forming unit 100 reaches its detection area, the entrance sensor 24 outputs a detection signal indicating this to the control unit. A wide variety of known sensors can be used as this type of sensor.

[0034] Furthermore, a skew sensor 21 is provided upstream of the skew correction roller pair 11 in the sheet conveying direction (near the center of the through conveying path W1) as a sheet edge detecting means for detecting the edge of the sheet P. When the leading edge of the sheet P conveyed from the image forming unit 100 reaches its detection area, the skew sensor 21 outputs a leading edge detection signal indicating this to the control unit. Any known sensor can be used as this sensor.

[0035] In this embodiment, a sheet detection sensor 22 is provided as sheet leading edge detection means for detecting the leading edge of the sheet P on the downstream side in the sheet conveying direction (the outlet side of the through conveying path W1) of the second conveying means constituted by the first forward / reverse rotating roller 13 and the pressing roller 14. When the leading edge of the sheet P conveyed on the through conveying path W1 reaches its detection area, the sheet detection sensor 22 outputs a leading edge detection signal indicating this to the sheet processing control unit 210. As with the skew sensor 21 described above, a wide variety of known sensors can be used for this sheet detection sensor 22.

[0036] Furthermore, in this embodiment, a sheet detection sensor 26 that detects the leading edge of the sheet P is provided downstream in the sheet conveying direction of the second forward / reverse roller pair 16 (opposite the outlet side of the branch conveying path W2). When the leading edge of the sheet P sent from the through conveying path W1 to the branch conveying path W2 reaches its detection area, the sheet detection sensor 26 outputs a leading edge detection signal indicating this to the sheet processing control unit 210. As with the inlet sensor 24, skew sensor 21, and sheet detection sensor 22 described above, a wide range of known sensors can be used for this sheet detection sensor 26.

[0037] In this embodiment, a circulation sensor 25 for detecting the leading edge of the sheet P is provided downstream in the sheet conveying direction of the second skew correction roller pair 17 as a circulation conveying roller pair. When the leading edge of the sheet P sent from the through conveying path W1 to the branch conveying path W2 reaches its detection area, the circulation sensor 25 outputs a leading edge detection signal indicating this to the sheet processing control unit 210. As with the inlet sensor 24, skew sensor 21, and sheet detection sensors 22 and 26 described above, a wide range of known sensors can be used for this circulation sensor 25.

[0038] In this embodiment, the first forward / reverse rotation roller 13 and the pressing roller 14 constitute a second sheet conveying means, and the first folding roller 12 and the first forward / reverse rotation roller 13 constitute a fold forming means. In this embodiment, the first forward / reverse rotation roller 13 and the second folding roller 15 also constitute a fold forming means.

[0039] [Folding process flow] Next, a description will be given of the flow and operation of the folding process for forming a fold in the sheet P by the folding process unit 200. Figures 5(a) to 5(d) are explanatory diagrams showing examples of folds formed by the folding process by the folding process unit 200 of this embodiment.

[0040] The folding processing unit 200 according to this embodiment performs a process of forming two outward folds on the sheet P to create a folded state as shown in FIG. 5(a). The outward fold illustrated in FIG. 5(a) is sometimes referred to as a "Z-fold." That is, the folding processing unit 200 can perform a Z-fold process. The folding processing unit 200 can also perform an inner tri-fold process, in which two inward folds are formed by dividing the sheet P into approximately thirds in the length direction, resulting in an inner tri-fold as shown in FIG. 5(b). The folding processing unit 200 can also perform an outer tri-fold process, in which two outward folds are formed by dividing the sheet P into approximately thirds, resulting in an outer tri-fold as shown in FIG. 5(c). The folding processing unit 200 can also perform a double-fold process, in which one fold is formed by dividing the sheet P into approximately two equal parts, resulting in a double-fold as shown in FIG. 5(d).

[0041] 6(a) to 6(h) are explanatory diagrams for explaining a general operation when Z-folding is performed by the folding processing unit 200. The leading edge of the sheet P, which is handed over from the discharge rollers on the image forming unit 100 side to the carry-in roller pair 10 and conveyed in a predetermined direction (hereinafter also referred to as forward conveyance) by the conveying roller pair 10 with a conveying force applied thereto, is first detected by the skew sensor 21. The control unit, having received a leading edge detection signal output from the skew sensor 21, controls the skew forward / reverse rotation motor 11m to start rotation of the skew correction roller pair 11 (FIGS. 6(a) and 6(b)).

[0042] Thereafter, when the leading edge of the sheet P enters the nip of the skew correction roller pair 11, a conveying force is also applied to the sheet P, and the sheet P is conveyed along the through conveying path W1 toward its exit side. The leading edge of the sheet P conveyed along the through conveying path W1 enters the nip between the first forward / reverse rotation roller 13 and the pressure roller 14, and after passing through this nip, is detected by the sheet detection sensor 22. The control unit receives a leading edge detection signal from the sheet detection sensor 22 that detects this and performs the following control. That is, when the leading edge of the sheet P protrudes from the nip position between the first forward / reverse rotation roller 13 and the pressure roller 14 by a predetermined protrusion amount (FIG. 6(c)), the control unit controls the first forward / reverse rotation motor 13m to stop the rotation of the first forward / reverse rotation roller 13. At the same time, the control unit controls the skew forward / reverse rotation motor 11m to stop the rotation of the drive roller 11b of the skew correction roller pair 11.

[0043] The amount of protrusion at this time is determined appropriately depending on the length of the sheet P in the sheet conveyance direction and the contents of the folding process (such as the folding method). The amount of protrusion of the leading edge of the sheet P can be determined, for example, from the timing of receiving the leading edge detection signal output from the sheet detection sensor 22 and the amount of rotation of the pressing roller 14.

[0044] Thereafter, the first forward / reverse motor 13m is controlled to start the reverse rotation of the first forward / reverse roller 13 in the direction returning the sheet P to the entrance side of the through conveyance path W1, and also start the rotation of the skew correction roller pair 11. As a result, a flexure is formed in the sheet portion between the skew correction roller pair 11 and the first forward / reverse roller 13 (FIG. 6(d)).

[0045] Then, this bent portion (folded portion) enters the nip between first folding roller 12 and first forward / reverse rotation roller 13, thereby forming a first fold at the folded portion. The first fold that has passed through the nip between first folding roller 12 and first forward / reverse rotation roller 13 enters branched conveying path W2 ( FIG. 6( e) ), and is conveyed along branched conveying path W2 toward second forward / reverse rotation roller pair 16.

[0046] The first folded portion of sheet P then enters the nip of second forward / reverse rotation roller pair 16, and after passing through this nip is detected by sheet detection sensor 26. The control unit receives a leading edge detection signal from sheet detection sensor 26 that detects this, and performs the following control: That is, when the first folded portion of sheet P protrudes from the nip position of second forward / reverse rotation roller pair 16 by a predetermined protrusion amount (FIG. 6(f)), first forward / reverse rotation motor 13m is controlled to stop the rotation of first forward / reverse rotation roller 13.

[0047] At the same time, the rotation of the second forward / reverse rotation roller pair 16 and the skew correction roller pair 11 is stopped. The amount of protrusion at this time is also determined appropriately depending on the length of the sheet P in the sheet conveyance direction and the contents of the folding process (such as the folding method). The amount of protrusion of the first folded portion of the sheet P can be determined, for example, from the timing of receiving the leading edge detection signal output from the sheet detection sensor 26 and the amount of rotation of the second forward / reverse rotation roller pair 16.

[0048] Thereafter, the second forward / reverse motor 16m is controlled to start the reverse rotation of the second forward / reverse roller pair 16 in the direction to move the sheet P toward the outlet side of the branch conveying path W2, and the reverse rotation of the first forward / reverse roller 13 and the rotation of the skew correction roller pair 11 are restarted. As a result, a flexure is formed in the sheet portion between the first forward / reverse roller 13 and the second forward / reverse roller pair 16 (FIG. 6(g)). Then, this flexure (folded portion) enters the nip between the first forward / reverse roller 13 and the second folding roller 15, and a second fold is formed in the folded portion.

[0049] The second folded portion that has passed through the nip between the first forward / reverse rotation roller 13 and the second folding roller 15 is conveyed toward the outlet side of the branch conveying path W2 (FIG. 6(h)). Then, the sheet P on which the two folded portions have been formed in this way receives a conveying force from the first forward / reverse rotation roller 13 and is conveyed to the post-processing device 3 at the downstream stage.

[0050] 7(a) to 7(h) are explanatory diagrams for explaining a general operation when the folding processing unit 200 performs inner three-folding processing.

[0051] 8(a) to 8(h) are explanatory diagrams illustrating the general operation of folding in three by the folding unit 200. The flow of operation for both folding in three and folding in three is the same as the Z-folding described above, but the protrusion amount and the protrusion length are different. Therefore, the timing at which the first forward / reverse rotation roller 13 and the second forward / reverse rotation roller pair 16 start rotating in reverse differs between the Z-folding, folding in three, and folding in three.

[0052] 9(a) to 9(h) are explanatory diagrams illustrating a typical operation when folding in half by the folding processing unit 200. The folding in half process is the same as the Z-folding process described above, except that the leading edge of the sheet P conveyed along the through-conveyance path W1 is not made to enter the nip between the first forward / reverse rotation roller 13 and the pressing roller 14, but is made to enter the nip between the first folding roller 12 and the first forward / reverse rotation roller 13, and the protrusion amount Δ2 is different. In this folding in half process, the first forward / reverse rotation roller 13 and the pressing roller 14 correspond to the first conveying means, and the second forward / reverse rotation roller pair 16 corresponds to the second conveying means. The folding in half may also be performed by the first fold forming means 20a.

[0053] [Folded Sheet Overlapping Processing] Next, a description will be given of a folded sheet overlapping process that can be performed in the folding process unit 200. In this embodiment, a plurality of sheets can be overlapped and folded while overlapping the plurality of sheets.

[0054] 10 to 14 are explanatory diagrams for explaining the operation of the sheet overlapping process by the folding process unit 200. Fig. 10 shows a state in which the preceding sheet is waiting for the arrival of the next sheet P at the junction of the circulating conveyance path W3 and the through conveyance path W1 by the circulating conveyance rollers. From this state, when the next sheet P is detected by the entrance sensor 24 and conveyed a specified distance, conveyance of the preceding sheet P is resumed by the circulating conveyance rollers (Fig. 11).

[0055] Thereafter, the sheet P is overlapped with the next sheet P in the through conveyance path W1 and conveyed to the skew correction roller pair 11. The leading ends of these sheets P abut against the nip of the skew correction roller pair 11, which serves as a leading end alignment conveyance roller pair, thereby correcting the skew of the two sheets P and also correcting the leading end misalignment (FIG. 12).

[0056] From here, the two sheets P are sent to the circulating conveying path W3. At this time, in the process of conveying along the circulating conveying path W3, a difference in conveying distance occurs between the sheet P passing through the relatively inner conveying path and the sheet P passing through the relatively outer conveying path, like an inner wheel difference. As a result, misalignment occurs at the leading edges of the overlapping sheets P (FIG. 13). The leading edges of these two sheets are brought into contact with the nip of the second skew correction roller pair 17, which is one of the circulating conveying roller pairs serving as the circulating conveying means, thereby correcting the misalignment of the leading edges of the sheets (FIG. 14).

[0057] In the second skew correction roller pair 17, the two sheets P whose leading edge misalignment has been corrected are returned from the circulating conveying path W3 to the through conveying path W1 (Figure 15), and then overlapped with the next sheet P and their leading edges aligned by the skew correction roller pair 11.

[0058] As described above, the folding processing unit 200 according to this embodiment is particularly effective when folding three or more sheets P stacked one on top of the other.

[0059] More specifically, this is effective when overlapping is performed after the first sheet P1 that has been conveyed first is overlapped with the second sheet P2 that has been conveyed next, and the two sheets P are brought into contact with the nip of the skew correction roller pair 11 to align the leading edges of the two sheets P.

[0060] That is, in order to correct the misalignment of the leading edges of the two sheets P that have been aligned by the skew correction roller pair 11 and are then sent to the circulating conveying path W3, the second skew correction roller pair 17, which is disposed downstream of the circulating conveying path W3, performs leading edge alignment again. Then, the multiple sheets P that have undergone leading edge alignment processing on the circulating conveying path W3 return to the through conveying path W1, and are further aligned with the leading edge of a new sheet (third sheet P3). At this time, the leading edges of the first and second sheets P2, which are being aligned, are abutted against the leading edge of the third sheet P3 at the nip of the skew correction roller pair 11, thereby performing leading edge alignment.

[0061] According to the overlapping and folding process performed by the sheet processing control section 210 according to the present embodiment described above, folding can be performed with the leading edges of a plurality of sheets P aligned.

[0062] [Aspects of the present invention] The contents of the present invention are as follows, for example. <1> a conveying means disposed on a conveying path that conveys a medium from upstream to downstream; a circulating conveying means arranged on a circulating conveying path that branches off from the conveying path and returns the medium to the upstream side of the conveying path; Equipped with At least one of the plurality of conveying roller pairs arranged in the circulating conveying path constitutes a misalignment correction conveying roller pair for correcting misalignment of the plurality of media caused by circulating conveyance in the circulating conveying path. A media processing device characterized by: <2> At least one of the plurality of conveying roller pairs arranged in the conveying path constitutes a leading edge aligning conveying roller pair for overlapping the media conveyed from upstream and aligning the leading edge positions of the media. The aforementioned <1> The media processing device described in <3> the pair of leading edge alignment conveying rollers is disposed downstream of a position where the circulating conveying path returns to the conveying path; The aforementioned <2> The media processing device described in <4> the misalignment correction conveying roller pair is arranged upstream of a position where the circulating conveying path returns to the conveying path, among the conveying roller pairs arranged in the circulating conveying path; The aforementioned <1> and above <3> 10. A media processing device according to claim 9, wherein: <5> a plurality of conveying roller pairs arranged on the conveying path and a plurality of conveying roller pairs arranged on the circulating conveying path, performing a superposing operation of superposing the plurality of media, and a folding operation of folding the superposed plurality of media in a predetermined manner; The aforementioned <1> and the above <4> 10. A media processing device according to claim 9, wherein: <6> An image forming apparatus including an image forming unit that forms an image on a medium and a medium processing unit that performs a predetermined process on the medium, The medium processing unit <1> and above <5> 10. An image forming apparatus comprising the media processing device according to claim 9. <7> an image forming apparatus including an image forming unit that forms an image on a medium; <1> and above <5> 10. An image forming system configured in connection with the media processing device according to any one of claims 1 to 9.

[0063] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist thereof. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0064] 1: Image forming device 3: Post-processing device 17: Second skew correction roller pair 17a: Pressure roller 17b: Drive roller 17m: Second skew correction motor 17s: Pressure spring 25: Circulation sensor 100: Image forming unit 200: Folding processing unit 210: Sheet processing control unit [Prior art documents] [Patent documents]

[0065] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-125312

Claims

1. a conveying means disposed on a conveying path that conveys a medium from upstream to downstream; a circulating conveying means arranged on a circulating conveying path that branches off from the conveying path and returns the medium to the upstream side of the conveying path; Equipped with At least one of the plurality of conveying roller pairs arranged in the circulating conveying path constitutes a misalignment correction conveying roller pair for correcting misalignment of the plurality of media caused by circulating conveyance in the circulating conveying path. A media processing device characterized by:

2. At least one of the plurality of conveying roller pairs arranged in the conveying path constitutes a leading edge aligning conveying roller pair for overlapping the media conveyed from upstream and aligning the leading edge positions of the media. The media processing device of claim 1 .

3. the pair of leading edge alignment conveying rollers is disposed downstream of a position where the circulating conveying path returns to the conveying path; The media processing device of claim 2 .

4. the misalignment correction conveying roller pair is arranged upstream of a position where the circulating conveying path returns to the conveying path, among the conveying roller pairs arranged in the circulating conveying path; The media processing device of claim 1 .

5. a plurality of conveying roller pairs arranged on the conveying path and a plurality of conveying roller pairs arranged on the circulating conveying path, performing a superposing operation of superposing the plurality of media, and a folding operation of folding the superposed plurality of media in a predetermined manner; The media processing device of claim 1 .

6. An image forming apparatus including an image forming unit that forms an image on a medium and a medium processing unit that performs a predetermined process on the medium, 2. An image forming apparatus, wherein the media processing unit is a media processing device according to claim 1.

7. 10. An image forming system comprising an image forming device having an image forming unit that forms an image on a medium, and the medium processing device according to claim 1, connected to one another.

Images