JP2019147679A - Sheet post-processing device and image forming system - Google Patents

Abstract

To provide a sheet post-processing device that imparts a mark on a sheet being carried, which aligns a sheet imparted with the mark and the other sheet vertically and laterally, and places the sheets at a discharge position.SOLUTION: A sheet post-processing device comprises: a sheet corner-folding mechanism 50, provided in a carrying passage 22 for a sheet 33, which corner-folds a corner part at a tip of the sheet being carried toward one side of the sheet; sheet stand-by mechanisms 26 and 113 which temporarily evacuate a precedent sheet carried to a downstream side from the sheet corner-folding mechanism on a sheet stand-by passage 27 and then return the sheet to the carrying passage; and a control CPU that controls operation of the mechanisms. The control CPU operates the sheet stand-by mechanism so that the precedent sheet returned from the sheet stand-by passage to the carrying passage and a subsequent sheet 34 overlap with each other at one side of the corner-folded sheet, on the carrying passage.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a sheet post-processing apparatus that can give a mark to a sheet to be conveyed, and an image forming system including the sheet post-processing apparatus.

  Conventionally, after alignment processing, binding processing, folding processing, punch punching processing, stamp stamping processing, etc., for recorded paper ejected from image forming apparatuses such as copiers, laser beam printers, facsimiles, and multifunction peripherals thereof Paper post-processing devices that perform processing are widely used. In general, a sheet post-processing device is connected to a sheet discharge port of an image forming apparatus, and stacks a sheet or a bundle of sheets subjected to desired post-processing on a discharge tray disposed on the downstream side.

  There are cases where it is desired to sort a large number of sheets discharged from the image forming apparatus into a discharge tray in the sheet post-processing apparatus, for example, for each set of a plurality of sheets or each document. In view of this, there has been proposed a bookmark creation apparatus that creates a bookmark by cutting a corner of a cover page of a document (sheet bundle) to be sorted and bending the cut corner to protrude outside the sheet. (For example, see Patent Document 1)

  The bookmark creating apparatus of Patent Document 1 includes a mechanism for rotating a cam using a pulse motor and moving a cutter for cutting the paper with the cam, and temporarily stops the conveyed paper. Operate and cut the paper. After that, the pulse motor is operated again, the cutter is retracted, the paper conveyance is resumed, and the cut portion is folded outward using a conveyance roller arranged downstream.

  Furthermore, the bookmark creation apparatus of Patent Document 1 is configured to change the position for creating a bookmark for each document in order to make it easier to sort documents for a plurality of received documents. For this purpose, the control unit manages how many times the cover page is output, controls the conveyance motor that drives the conveyance roller of the recording sheet, and changes the stop position of the recording sheet in the processing device that moves the cutter up and down. ing.

JP-A-9-107433

  In the paper post-processing apparatus, when marks are added to the conveyed paper, it is preferable that the discharged paper is stacked in a state in which the discharged paper is aligned vertically and horizontally. However, as in the conventional apparatus described in Patent Document 1, when a mark is given by folding a part of a sheet to be conveyed, the folded sheet portion is another sheet that has been previously stacked on the discharge tray. There is a risk of being caught on the edge of other paper discharged later.

  As a result, there arises a problem that a large number of sheets are stacked vertically and horizontally on the discharge tray. However, even in Patent Document 1 and other prior arts, a part of the paper is folded and a mark is added to the paper and the other paper are stacked on the discharge tray without being separated vertically and horizontally. The specific technology for this is neither disclosed nor proposed.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a sheet post-processing apparatus that applies a mark to a sheet to be conveyed. And loading them at a predetermined discharge position.

  A further object of the present invention is to provide the above-described sheet post-processing apparatus of the present invention, to mark the sheets discharged from the image forming apparatus, and to stack them in a predetermined discharge position by aligning them vertically and horizontally with other sheets. To provide an image forming system.

In the first aspect of the sheet post-processing apparatus of the present invention,
A paper transport path for transporting paper,
A transport mechanism for transporting paper along the paper transport path;
A corner folding processing mechanism for corner-folding at least one corner of the leading edge of the sheet conveyed in the predetermined conveying direction by the conveying mechanism to one surface side of the sheet;
The preceding sheet transported downstream from the corner folding mechanism in the transport direction is temporarily retracted to a standby position for retracting from the sheet transport path, and the preceding sheet is temporarily retracted from the sheet transport path. A paper standby mechanism for returning the paper from the standby position to the paper transport path;
A control unit for controlling operations of the transport mechanism, the corner folding processing mechanism, and the paper standby mechanism;
The controller, when returning the preceding sheet, which has been folded by the corner folding processing mechanism, from the standby position to the sheet conveyance path, on the one surface side where the preceding sheet has been folded, The sheet standby mechanism is operated so that the sheet that is not folded at an angle subsequent to the preceding sheet is overlapped on the sheet conveyance path.

In the second aspect of the sheet post-processing apparatus of the present invention,
A paper transport path for transporting paper,
A transport mechanism for transporting paper along the paper transport path;
A corner folding processing mechanism for corner-folding at least one corner of the leading edge of the sheet conveyed in the predetermined conveying direction by the conveying mechanism to one surface side of the sheet;
The preceding sheet transported downstream from the corner folding mechanism in the transport direction is temporarily retracted to a standby position for retracting from the sheet transport path, and the preceding sheet is temporarily retracted from the sheet transport path. A paper standby mechanism for returning the paper from the standby position to the paper transport path;
A control unit for controlling operations of the transport mechanism, the corner folding processing mechanism, and the paper standby mechanism;
The controller, when returning the preceding sheet that has not been folded by the corner folding processing mechanism from the standby position to the sheet transport path, follows the preceding sheet and is transported by the transport mechanism. The sheet standby mechanism is operated so that the sheet folded by the corner folding processing mechanism overlaps the preceding sheet and the sheet conveyance path on the one side of the corner folded.

  In another aspect of the present invention, an image forming system of the present invention includes an image forming unit that forms an image on a sheet, and a sheet post-processing device that performs a corner folding process on the sheet sent from the image forming unit. The processing apparatus is the paper post-processing apparatus of the present invention described above.

  According to the sheet post-processing apparatus of the present invention, even when either the preceding sheet or the succeeding sheet is folded by the sheet corner folding mechanism, the sheet is folded at one side of the folded sheet. The operation of the sheet standby mechanism is controlled by the control unit so that the portion and the other sheet overlap. As a result, the corner portion of the folded sheet is covered with the other sheet, so that there is no possibility of being caught by the sheet stacked at the discharge position or the sheet discharged later. Then, the folded paper and other paper can be stacked in the vertical and horizontal directions and stacked at the discharge position.

1 is a diagram schematically showing an overall configuration of an image forming system. The side view which shows the structure of the principal part of the paper post-processing apparatus in the system of FIG. FIG. 3 is a schematic perspective view illustrating a configuration of a sheet corner folding mechanism of the sheet post-processing apparatus according to the present invention. FIG. 4 is a cross-sectional view illustrating a configuration of a sheet corner folding mechanism illustrated in FIG. 3. FIG. 4 is a top view illustrating a configuration of a sheet corner folding mechanism in FIG. 3. Sectional drawing which shows the corner folding operation | movement by the paper corner folding mechanism of FIG. 3 in order. FIG. 4 is a top view sequentially illustrating a corner folding operation by the sheet corner folding mechanism of FIG. 3. Sectional drawing for demonstrating the operation | movement which superimposes the paper of a waiting position, and a subsequent paper. FIG. 3 is a plan view schematically showing a configuration of an alignment mechanism. FIG. 3 is a block diagram illustrating a control configuration of a sheet post-processing apparatus. The flowchart explaining the setting of the corner folding instruction | indication in a user operation part. 9 is a flowchart for explaining a series of sheet conveyance processes including corner folding processing.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments of the invention will be described below with reference to the accompanying drawings.

[Image forming system]
FIG. 1 shows the overall configuration of an image forming system according to the present invention. The image forming system shown in FIG. 1 includes an image forming apparatus A and a sheet post-processing apparatus B. After the sheets formed by the image forming apparatus A are temporarily aligned and stored in the sheet post-processing apparatus B, after staple binding or the like. After processing, it is stored in the discharge tray. The paper post-processing apparatus B is configured to store the paper in the discharge tray after finishing processing according to the post-processing (finishing processing) mode set together with the image forming conditions in the image forming apparatus A. Hereinafter, the image forming apparatus A and the sheet post-processing apparatus B will be described.

[Image forming apparatus]
The image forming apparatus A shows a case where an image is formed on a sheet by an electrostatic printing mechanism, and is constituted by a paper feed unit 2, an image forming unit 3, and a paper discharge unit 4. The apparatus housing 1 of the image forming apparatus A includes a sheet feeding unit 2 that stores sheets for image formation. The sheet feeding unit 2 includes sheet feeding cassettes 2a, 2b, and 2c that are detachable from the apparatus housing 1. The paper feed cassettes 2a, 2b, and 2c correspond to different paper sizes.

  The image forming unit 3 forms an image according to the image data transferred from the data processing unit 9 onto the sheet conveyed from the sheet feeding unit 2. The illustrated image forming unit 3 shows an electrostatic printing mechanism, and includes a beam projector that forms an electrostatic latent image on the photosensitive drum 8, a developing unit 10 that attaches toner ink to the electrostatic latent image, a transfer charger 11, and a cleaner. It consists of Since these specific configurations and operations are widely known, detailed description thereof will be omitted.

  The image ink formed on the photosensitive drum 8 is transferred by the transfer charger 11 to the sheet conveyed from the sheet feeding unit 2 to the registration roller pair 7. A fixing roller pair 12 is disposed on the downstream side of the transfer charger 11, heat-fixes the transferred image, and conveys the paper to the paper discharge unit 4. The paper discharge unit 4 includes an image forming apparatus paper discharge port 13 disposed in the apparatus housing 1 and a paper discharge roller pair 15.

  The data processing unit 9 receives the image data read by the image reading unit 5 or the image data sent from an external network, a computer input device, etc. as an electrical signal to the beam projector according to the set image forming conditions. Send.

  The illustrated image forming apparatus A includes an image reading unit 5 integrated with the image forming apparatus A, and an automatic document sheet feeder 19 for feeding document sheets to the unit. The image reading unit 5 includes a platen 16 on which a document sheet is placed and a reading carriage 17 that moves along the platen 16. The document sheet on the platen 16 is scanned by the reading carriage 17 and converted into image data. It consists of a scanner device. Further, the automatic document sheet feeder 19 is integrally attached to the image reading unit 5 as a unit for automatically feeding document sheets set on the sheet feeding tray 20 to the platen 16.

  The duplex path 14 reverses the paper on which the image is formed from the image forming unit 3 and circulates and conveys the paper to the registration roller pair 7, forms an image on the back side of the paper with the image forming unit 3, and forms an image from the paper discharge unit 4. It is carried out to the apparatus discharge port 13.

  In addition to the electrostatic printing mechanism, the image forming apparatus A can employ various image forming mechanisms such as an inkjet image forming method, an offset printing method, and a silk printing method.

"Paper finishing device"
As shown in FIG. 1, the sheet post-processing apparatus B of the present invention, when an image-formed sheet is carried in from the image forming apparatus A, stores the sheet in a processing tray 29 and then finishes it after finishing. Processing (staple binding processing, folding processing, etc.) is performed, and the processed paper (or paper bundle) is stored in the discharge tray 32.

  FIG. 2 shows the configuration of the sheet post-processing apparatus B in detail. The sheet post-processing apparatus B includes an apparatus housing 21. In the apparatus housing 21, a conveyance path 22 that conveys the sheet, a sheet corner folding mechanism 50 that performs a corner folding process on the leading corner of the conveyed sheet, and a conveyance. The paper standby path 27 for temporarily retracting the paper to be transported from the transport path 22 and waiting, the processing tray 29 for temporarily storing the paper transported from the transport path 22, and the post-processed paper are stacked and stored. It comprises a discharge tray 32.

  Hereinafter, the sheet post-processing apparatus B according to the first embodiment of the present invention will be described in detail.

[Transport route]
The conveyance path 22 (paper conveyance path) is formed so as to cross the apparatus housing 21 in a straight line in a substantially horizontal direction. On the entrance side of the transport path 22, a transport port 101 connected to the image forming apparatus discharge port 13 is provided so as to guide the sheet transported from the image forming apparatus A toward the processing tray 29 on the downstream side. It is configured.

  In the transport path 22, a pair of carry-in rollers 24 and a pair of discharge rollers 25 constituting a paper transport unit are sequentially arranged on the upstream side and the downstream side along the paper transport direction. The carry-in roller pair 24 and the discharge roller pair 25 are respectively connected to a conveyance roller drive motor (not shown), and are driven by the conveyance roller drive motor to convey the sheet from the carry-in entrance 101 to the paper discharge outlet 103.

  Further, a carry-in sensor 23 is arranged on the carry path 22 on the carry-in entrance 101 side of the carry-in roller pair 24. When the carry-in sensor 23 detects the leading edge and the trailing edge of the paper conveyed from the carry-in port 101, the carry-in sensor 23 transmits a detection signal to the control CPU 203 incorporated in the control unit 200 of the paper post-processing apparatus B described later.

"Paper folding mechanism"
The sheet corner folding mechanism 50 is located between the carry-in roller pair 24 and the discharge roller pair 25 on the transport path 22 and performs a later-described corner folding process on the sheet 33 transported through the transport path 22. 3 is a perspective view of the sheet corner folding mechanism 50, FIG. 4 is a sectional view thereof, and FIG. 5 is a top view thereof.

  The sheet corner folding mechanism 50 includes upper and lower flappers 51 and 52, upper and lower sheet guides 53 and 54, and a pair of folding rollers 55. As shown in FIG. 4, the upper and lower flappers 51 and 52 and the upper and lower paper guides 53 and 54 are provided vertically symmetrically with respect to the transport path 22.

  As shown in FIGS. 3 and 4, the transport path 22 is limited by a narrow gap in the up and down direction on the upstream side in the paper transport direction with respect to the folding roller pair 55 except for the upper and lower paper guides 53 and 54. ing. Due to this gap, the leading edge of the sheet 33 being conveyed in the conveyance path 22 does not change to the outside of the conveyance path, that is, does not change in the vertical direction (upward or downward) with respect to the surface of the sheet 33. It is configured.

  In the gap of the conveyance path 22, the portions where the upper and lower paper guides 53 and 54 are provided are cut out, respectively, from the first side parallel to the paper conveyance direction and the upstream side of the first side in the paper conveyance direction. A second side extending outward to the side of the transport path 22 in parallel with the paper width direction, and a downstream end in the paper transport direction of the first side and an outer end in the paper width direction of the second side are connected in an oblique straight line. A triangular opening composed of the third side is formed. The upper and lower paper guides 53 and 54 project outward from the triangular opening so as to close the triangular opening of the transport path 22.

  As shown in FIGS. 3 to 5, the upper sheet guide 53 is erected from the first side and the second side of the triangular opening to the outside of the conveyance path 22 and slightly inclined to the inside of the triangle. The flat and substantially fan-shaped first and second wall portions, and the substantially triangular third wall portion curved from the third side to the outside of the conveyance path 22 and curved to the inside of the triangle. The first and second wall portions are integrally coupled with the first side and the second side at a straight side extending from the intersection, and the third wall portion has both sides on the first and first sides. The two wall portions are integrally coupled to the substantially fan-shaped curved side.

  As a result, a sealed space for bending the corner of the sheet to the outside of the transport path 22 is defined inside the upper sheet guide 53 as will be described later. The inclination angle of the corner fold formed at the corner of the sheet 33 is determined by the third side of the triangle forming the third wall of the upper sheet guide 53. Since the lower paper guide 54 is provided vertically symmetrically with the upper paper guide 53, description thereof is omitted.

  The upper flapper 51 and the lower flapper 52 are each formed of a rectangular flat plate member having the same size and shape, and project from the second side of the triangular opening above and below the conveyance path 22 so as to be within the opening. The upper and lower flappers 51 and 52 are respectively outwardly with respect to the transport path 22 around the sheet width direction, ie, upward and downward in the vertical direction, at or near the second sides of the triangular openings above and below the transport path 22. The upper and lower paper guides 53 and 54 are supported so as to swing within the space defined by the upper and lower paper guides 53 and 54.

  The upper and lower flappers 51 and 52 change the corner of the sheet 33 conveyed at a position overlapping with the upper and lower flappers to the outside in the conveying direction (vertically upward or downward), that is, the sheet corner guiding means (first step). 1 guiding means). The upper and lower paper guides 53 and 54 are paper corners for curling the corners of the paper 33 turned to the outside in the transport direction by the upper and lower flappers 51 and 52 inwardly, that is, the paper side. It has a function as a part guide means (second guide means). As will be described later, the corner portion of the sheet 33 to be subjected to corner folding is bent as shown in FIGS. 4 and 5 by the combination of the upper and lower flappers and the upper and lower sheet guides.

  A folding roller pair 55 is provided adjacent to the upstream end of the transport path 22 and the downstream end of the lower paper guides 53 and 54 in the paper transport direction as a corner folding means for folding the corner of the paper 33 bent in this way. It has been. As shown in FIG. 5, the pair of folding rollers 55 has a length, that is, a dimension in the sheet width direction, that is larger than the width of the corner folding portion applied to the sheet 33 to be conveyed. It arrange | positions so that the whole folding part may be press-contacted.

  The pair of folding rollers 55 is provided only at positions corresponding to the corners of the sheet to be subjected to the corner folding process in the sheet width direction. For this reason, if the folding roller pair 55 is set so that the same sheet conveying force as that of the carry-in roller pair 24 or the discharge roller pair 25 can be exerted between the upper and lower folding rollers, a skew is caused in the conveyed sheet 33. There is a risk of generating. Therefore, the folding roller pair 55 is set such that the sheet conveying force is smaller than that of the carry-in roller pair 24 and the discharge roller pair 25.

  The folding roller pair 55 of this embodiment is driven by the same drive source (drive motor) as the carry-in roller pair 24, but is configured to be driven by the same drive source (drive motor) as the discharge roller pair 25. You can also. In the present embodiment, as the corner folding means, the folding roller pair 55 composed of the upper and lower roller pairs similar to the carry-in roller pair 24 or the discharge roller pair 25 is employed, but other corner folding means are also possible. For example, a configuration such as a pair of driven rollers having a gap narrow enough to form a corner fold, or a pair of curved guides having a narrow gap, although the corners of the bent paper are not pressed against each other. In these cases, the corner folding means can be set so as not to have a sheet conveying force.

  Next, a corner folding operation by the sheet corner folding mechanism 50 will be described. FIG. 6 is a view in which the corners of the paper 33 being transported along the transport path 22 is folded upward by the paper corner folding mechanism 50, that is, the process of forming the upward corner folds is viewed in order from the cross-sectional direction. FIG. 7 is a view of these processes as viewed from above.

  The sheet 33 carried into the sheet post-processing apparatus B is conveyed toward the sheet corner folding mechanism 50 by the pair of carry-in rollers 24 on the conveyance path 22. At that time, the conveyance position of the sheet 33 is confirmed by the carry-in sensor 23 detecting the leading edge and the trailing edge of the sheet.

  When the sheet 33 is not subjected to the corner folding process, the upper flapper 51 and the lower flapper 52 are maintained at the same height as the transport path 22, that is, horizontally in the present embodiment, as shown in FIGS. Accordingly, the sheet 33 passes through the pair of folding rollers 55 as it is in the normal sheet conveyance without being bent or bent at the corners of the conveyance path 22. Whether or not the sheet 33 is subjected to the corner folding process is determined by the presence or absence of an instruction from the main body control unit 202 provided in the image forming apparatus A, as will be described later.

  When the main body control unit 202 gives an instruction for the upper folding process at the corner, the upper flapper 51 and the lower flapper 52 are swung upward to a predetermined angular position as shown in FIGS. 6B and 7B. As a result, as shown in FIGS. 6B and 7B, the corner portion of the paper sheet 33 that is being conveyed is turned so as to bend upward while being conveyed. Be guided to. At this time, the upper flapper 51 and the lower flapper 52 are swung while maintaining the path width of the transport path 22 so that the corner of the sheet 33 can be easily guided into the upper sheet guide 53.

  As shown in FIGS. 6C and 7C, the corner portion of the sheet 33 that is turned upward and guided into the upper sheet guide 53 is moved upward as the sheet 33 continues to be conveyed in the sheet conveying direction. Along the curved surface of the third wall portion of the paper guide 53, the paper guide 53 is bent inwardly, that is, curled and bent toward the paper side. The upper and lower flappers 51 and 52 are returned to the original horizontal position after the corner of the paper 33 reaches the upper paper guide 53 and before the leading edge of the paper reaches the nip position of the pair of folding rollers 55.

  The sheet 33 is conveyed on the conveyance path 22 toward the folding roller pair 55 as it is, with the corners being bent as described above. As a result, the bent corner of the sheet 33 is sandwiched between the folding rollers of the pair of folding rollers 55 and conveyed while being pressed and pressed from above and below. As a result, as shown in FIGS. 6D and 7D, an upward folding process is performed at the corners of the sheet 33 to form an upward corner folding part.

  When the main body control unit 202 gives an instruction for the downward folding process at the corner, the upper flapper 51 and the lower flapper 52 are swung downward to a predetermined angular position. As a result, the corner portion of the sheet 33 is turned downward, guided into the lower sheet guide 54, and bent downward. The corner portion of the sheet 33 bent downward is processed in the same manner as the above-described upper folding process of the corner portion, and is pressed by the pair of folding rollers 55 to form a downward corner folding portion.

  The sheet 33 subjected to the corner folding process is transferred to the discharge roller pair 25 and conveyed, and is discharged to the discharge tray 32. At this time, if the corner portion of the sheet 33 is nipped by the discharge roller pair 25 and conveyed, the corner fold portion can be additionally folded by the pressure contact force of the discharge roller pair 25. This is advantageous because the corner folds can be formed more reliably. For example, the length of the discharge roller pair 25 disposed on the sheet corner folding mechanism 50 side in the sheet width direction of the transport path 22 is made longer than usual, or an additional discharge roller pair 25 is disposed, This is achieved by configuring the corner portion of the sheet 33 subjected to the corner folding process by the sheet corner folding mechanism so as to be conveyed through the sheet width direction position nipped by the discharge roller pair 25.

  In this embodiment, the upper flapper 51 and the lower flapper 52 are used as the sheet corner portion guiding means (first guiding means) for turning the corner portion of the sheet to the outside of the conveyance path 22. It is not limited to. Various configurations different from the upper and lower flappers 51 and 52 are conceivable as long as the corners of the sheet 33 being conveyed can be bent upward or downward from the conveyance path 22.

  For example, a flexible and highly durable resin sheet member made of PET (polyethylene terephthalate) or the like is inclined at an angle of at least one of upward and downward at an angle, and the upper and lower paper guides 53 and 54 described above. It is also possible to provide the second side of the triangular opening with a fixed inclination angle, or to provide a fixed projection or the like having a shape that changes the end of the sheet in the middle of the conveyance path 22. When these fixed turning means are used, the corners of the paper passing through the position of the turning means are always subjected to corner folding processing. It is preferable to shift the transport position in the paper width direction so as not to pass.

  In the present embodiment, one sheet corner folding mechanism 50 is provided in the conveyance path 22 so that only one corner of the sheet is folded. In another embodiment, two sheet corner folding mechanisms 50 can be provided in the width direction of the conveyance path 22. In this case, both the sheet folding mechanisms 50 are configured to be bilaterally symmetric with respect to the sheet conveyance direction, and the third wall portions of the upper and lower sheet guides 53 and 54 have curved surfaces that are curved with respect to the width of the conveyance path 22. Arranged to face each other. As a result, both corners on the leading end side of the sheet or one of the corners can be selectively subjected to corner folding.

"Paper standby path"
As shown in FIGS. 2 and 8, the paper standby path 27 temporarily retracts the paper 33 that is transported to the downstream side in the paper transport direction through the transport path 22 beyond the paper corner folding mechanism 50. It is provided on the downstream side of the corner folding mechanism 50 so as to branch downward from the conveyance path 22 in the drawing. A standby roller pair 26 is provided in the paper standby path 27 at a position slightly inserted from the connecting portion 22 a with the transport path 22. The standby roller pair 26 is driven by a standby roller drive motor 114 described later, and is used to move the paper 33 from the transport path 22 into the paper standby path 27 and return it to the transport path.

  A path switching flapper 113 is disposed at a connection portion 22 a between the paper standby path 27 and the transport path 22. The path switching flapper 113 is pivotally supported with the base end portion on the upstream side in the transport direction as a fulcrum and the downstream end portion swingable up and down in the drawing. The path switching flapper 113 is driven by a path switching flapper drive motor 115 to be described later, and a discharge transport position that allows the paper 33 to be transported from the upstream side to the downstream side along the transport path 22 and the transport path 22. It swings between the downstream side of the switching flapper 113 and the standby conveyance position that enables conveyance of the paper 33 toward the paper standby path 27. Usually, the path switching flapper 113 is disposed at the discharge conveyance position so that the paper 33 carried in from the carry-in entrance 101 is conveyed to the paper discharge port 103 by the carry-in roller pair 24 and the discharge roller pair 25 on the conveyance path 22. ing.

  The paper 33 that is retracted to the paper standby path 27 is transported toward the paper discharge port 103 through the transport path 22 until the paper discharge sensor 102 detects the trailing edge. When the paper discharge sensor 102 detects the trailing edge of the paper 33, the paper discharge roller pair 25 is stopped and reversely rotated while the paper is nipped, and the paper 33 is conveyed in the reverse direction on the conveyance path 22. At this time, the path switching flapper 113 moves from the discharge conveyance position to the standby conveyance position before the discharge roller pair 25 starts to reverse. At the standby transport position of the path switching flapper 113, the leading end 113a of the path switching flapper is swung so as to overlap the connecting portion 22a between the transport path 22 and the paper standby path 27, or at least inside the paper standby path 27. It arrange | positions so that it may become this position. Thereby, there is no possibility that the corner folding portion of the paper 33 retracted to the paper standby path 27 is caught by the connecting portion 22a.

  As a result, the sheet 33 is switched back along the conveyance path 22, and its upstream end (rear end in the conveyance direction) is guided by the path switching flapper 113 and conveyed into the sheet standby path 27. In the paper standby path 27, the paper 33 is conveyed further back by the standby roller pair 26. As shown in FIG. 8, the standby roller pair 26 stops in the state where the vicinity of the downstream end in the transport direction of the paper 33 is nipped. The stop of the standby roller pair 26 is controlled based on the timing at which the paper discharge sensor 102 detects the downstream end in the transport direction of the paper 33 that is switched back along the transport path 22.

"Simultaneous paper ejection"
The transport path 22 is configured such that the paper that has been waiting on the paper standby path 27 is simultaneously discharged from the paper discharge outlet 103 so that the transport path 22 overlaps with the subsequent paper transported from the transport inlet 101 to the paper discharge outlet 103. Returned to Which sheet to be carried in from the carry-in entrance 101 is made to wait in the sheet standby path 27 is determined by an instruction from the main body control unit 202 based on the setting of the corner folding process performed by the sheet corner folding mechanism 50.

  When the corner folding process is set, as shown in FIG. 8, the preceding sheet 33 subjected to the corner folding process by the sheet corner folding mechanism 50 is switched back and conveyed to the sheet standby path 27 as described above. Wait. In the paper standby path 27, the paper 33 is nipped between the standby roller pair so that the corner folding portion on the leading end side in the transport direction is positioned between the connection portion 22 a to the transport path 22 and the standby roller pair 26. Retained.

  Next, as shown in FIG. 8, when the subsequent paper 34 that has not been subjected to the corner folding process is transported through the transport path 22, the standby roller pair 26 is driven to transfer the paper 33 from the paper standby path 27. 22 to send. The sheet 33 is overlapped with the succeeding sheet in the transport path 22 so that the leading end in the transport direction does not precede the leading end of the succeeding sheet 34. The paper 33 and the paper 34 are transported along the transport path 22 in the transport direction by the discharge roller pair 25 while being overlapped, and are simultaneously discharged from the paper discharge outlet 103.

  The paper 33 and the paper 34 discharged from the paper discharge outlet 103 are discharged and stacked on the paper tray 32a of the discharge tray 32 via the reverse roller pair 28 that rotates in the forward direction when finishing post-processing is not performed. When post-finishing processing is performed on the paper 33 and the paper 34, both the paper 33 and 34 are stacked on the paper mount 29a of the processing tray 29 by reversing the reversing roller pair 28 as described later.

  The delivery of the paper 33 from the paper standby path 27 is performed in accordance with the timing when the leading edge of the subsequent paper 34 reaches the connecting portion 22a between the paper standby path 27 and the transport path 22. This timing is determined based on, for example, the timing when the carry-in sensor 23 detects the leading edge of the succeeding paper 34, the paper conveyance speed of the carry-in roller pair 24, and the like.

  When the paper 33 is sent out from the paper standby path 27, the subsequent paper 34 passes through the connecting portion 22 a between the transport path 22 and the paper standby path 27 at the same time. For this reason, the path switching flapper 113 is disposed at a position where the sheet can simultaneously pass from both the upstream side of the transport path 22 and the sheet standby path 27. This is realized by setting the discharge conveyance position in this way in advance. In another embodiment, the discharge transport position is set so that the paper standby path 27 is completely blocked and the transport path 22 is released, and when the paper 33 is sent out from the paper standby path 27, a path switching flapper is used. It is also possible to dispose the sheet 113 at an intermediate position between the discharge conveyance position and the standby conveyance position to allow simultaneous passage of sheets.

  As described above, the succeeding sheet 34 that has not been subjected to the corner folding process is overlapped on the upper surface side of the preceding sheet 33, so that the upward corner folding portion of the leading end of the sheet 33 is covered with the succeeding sheet 34. Since the paper is discharged from the paper discharge port 103 in this state, there is no possibility that the paper discharged from the paper discharge port 103 will be caught by the upward corner folding portion of the paper 33 thereafter. Therefore, the paper 33 and the following paper can be aligned vertically and horizontally and stacked on the paper loading surface of the discharge tray 32 or the processing tray 29.

  When the upward processing of the corner portion is performed on the last sheet of a series of sheets that are continuously carried from the image forming apparatus A to the sheet post-processing apparatus B and finally discharged to the discharge tray 32, the last sheet is There is no subsequent paper to be superimposed. After the last sheet is discharged to the discharge tray 32 (or the processing tray 29), the discharge tray 32 (or processing) is started before the operation for carrying the sheet from the image forming apparatus A to the sheet post-processing apparatus B is started. If the series of sheets has been removed from the tray 29), there is no sheet to be discharged on the last sheet on the discharge tray 32 (or the processing tray 29). Does not occur.

  However, before removing the series of sheets previously stacked on the discharge tray 32 (or the processing tray 29), the next operation of carrying the sheets from the image forming apparatus A to the sheet post-processing apparatus B may start. . In that case, another sheet is discharged onto the last sheet on the discharge tray 32 (or the processing tray 29), thereby causing a problem that the alignment of the sheets is impaired. This problem is caused by, for example, performing a corner folding process on the last sheet by the sheet corner folding mechanism 50, then temporarily retracting the sheet to the sheet standby path 27, and carrying in an additional sheet on which no image is formed from the image forming apparatus A. As described above, the sheet is overlapped and discharged from the sheet discharge outlet 103 at the same time. The additional sheet can be carried in by an instruction from the main body control unit 202 based on the setting of the corner folding process described above.

  When the corner folding process is set, the preceding sheet conveyed on the conveyance path 22 immediately before the sheet 33 to be corner-folded is not discharged from the sheet discharge outlet 103, and is related to FIG. As described above, switchback conveyance is performed, and the vicinity of the leading end in the conveyance direction is made to wait in the sheet standby path 27 with the standby roller pair 26 nipped. Next, when the sheet 33 whose corner is folded downward by the sheet corner folding mechanism 50 is conveyed along the conveyance path 22, the standby roller pair 26 is driven, and the preceding sheet is conveyed from the sheet standby path 27 to the conveyance path. 22 to send. The sheet 33 is overlapped with the preceding sheet in the conveying path 22 so that the leading end in the conveying direction does not precede the leading end of the preceding sheet.

  The paper 33 discharged from the paper discharge port 103 and the preceding paper are discharged and stacked on the paper tray 32a of the discharge tray 32 via the reverse roller pair 28 that normally rotates when finishing post-processing is not performed. . When finishing post-processing of the paper 33 and the preceding paper, the paper is stacked on the paper platform 29a of the processing tray 29 by reversing the reversing roller pair 28 as described later.

  The preceding paper is sent out from the paper standby path 27 in accordance with the timing at which the leading edge of the paper 33 reaches the connecting portion 22 a between the paper standby path 27 and the transport path 22. This timing is determined based on, for example, the timing when the carry-in sensor 23 detects the leading edge of the paper 33, the paper conveyance speed of the carry-in roller pair 24, and the like.

  As described above, the preceding corner sheet that has not been subjected to the corner folding process is overlapped on the lower surface side of the sheet 33, so that the downward corner folding portion at the leading end of the sheet 33 is covered with the preceding sheet. Since the paper is discharged from the paper discharge port 103 in this state, there is no possibility that the downward corner folding portion of the paper 33 is caught by the paper discharged from the paper discharge port 103 first. Accordingly, it is possible to stack the sheets stacked on the discharge tray 32 or the processing tray 29 and the sheets 33 in the vertical and horizontal directions.

  In the case where corner downward processing is performed on the first sheet of a series of sheets that are continuously carried from the image forming apparatus A to the sheet post-processing apparatus B and finally discharged to the discharge tray 32, the first sheet There is no preceding paper to be superimposed. When the first sheet is discharged to the discharge tray 32 (or the processing tray 29), if there is no other sheet previously loaded on the discharge tray 32 (or the processing tray 29), the above-described sheet alignment is performed. The problem does not occur. However, when another sheet remains in the discharge tray 32 (or the processing tray 29), when the first sheet is discharged thereon, the downward corner folding portion of the first sheet is caught by the other sheet, This causes a problem that the alignment of the paper is impaired.

  The problem is that, for example, an already loaded paper presence / absence sensor 116 described later is provided in the discharge tray 32 (or the processing tray 29) to detect the presence / absence of paper loaded on the discharge tray 32 (or the processing tray 29) in advance. Is eliminated. That is, when no paper is detected on the discharge tray 32 (or the processing tray 29), the first paper subjected to the corner folding process is directly discharged from the paper discharge port 103 of the transport path 22. When a sheet is detected in the discharge tray 32 (or the processing tray 29), the first sheet is prevented from being a sheet that has undergone a downward folding process at the corner.

  Therefore, in an embodiment, the first sheet is not folded at the corner, but is folded upward. Correspondingly, in the image forming apparatus A, the first sheet and subsequent sheets output in series with the first sheet are subjected to image formation by reversing the front and back of the sheets, and the sheet post-processing apparatus B Reverse the order of output to. As a result, a series of sheets including the first sheet is processed and discharged in the same manner as in the case where the above corner corner folding process is set. This operation can be performed by an instruction from the main body control unit 202.

  In another embodiment, when there are sheets stacked on the discharge tray 32 (or the processing tray 29), a preceding sheet on which no image is formed is transferred from the image forming apparatus A to the sheet post-processing apparatus immediately before the first sheet. Set to discharge to B. The preceding paper carried into the paper post-processing device B is not discharged from the paper discharge outlet 103 as described above, but is kept in the paper standby path 27, and the first paper carried in after that is the paper corner folding mechanism. In accordance with the timing when the corner portion is folded downward at 50 and conveyed along the conveyance path 22, the sheet can be returned to the conveyance path 22 and overlapped with the first sheet, and simultaneously discharged from the sheet discharge outlet 103.

  Further, it is not preferable that the two sheets subjected to the corner folding process are overlapped as described above and discharged from the sheet discharge outlet 103 at the same time. For example, when two sheets are subjected to corner folding processing in the same upward, downward, or facing direction, the corner folding portion of one preceding sheet is caused by a positional deviation of the leading end of the sheet that occurs when the sheets are overlapped with each other. May be caught on the other sheet. When the two sheets are subjected to a corner folding process outwardly, there is no possibility of the sheets catching each other, but the corner folding sections of both sheets are stacked on the discharge tray 32 or the processing tray 29 first. It will catch on other paper and other paper discharged later. Therefore, it is preferable that the succeeding or preceding paper discharged at the same time as the paper subjected to the corner folding processing is limited to the paper not subjected to the corner folding processing as described above.

"Processing tray"
A processing tray 29 is disposed on the downstream side of the paper discharge port 103. The processing tray 29 includes a processing tray paper mounting table 29a that supports the rear end portion in the paper discharge direction (the direction from right to left in FIG. 2). The processing tray paper mount 29a is disposed so as to bridge-support the paper conveyed from the paper discharge outlet 103 to the discharge tray 32 in a substantially horizontal direction.

  The processing tray 29 is provided with a restriction stopper 105 and a staple unit 31 for restricting the position of the rear end portion in the paper discharge direction. Therefore, the paper discharged from the transport path 22 is reversely transported in the direction opposite to the discharge direction (rightward in FIG. 2) and stored in the processing tray 29 disposed below the paper discharge port 103. . The staple unit 31 is a well-known unit that has been conventionally used, and binds a bundle of sheets stacked and aligned on the processing tray paper platform 29a by reverse conveyance with a staple.

"Alignment mechanism"
As shown in FIG. 2, the processing tray 29 has an alignment mechanism 30 that is an alignment unit that moves forward and backward in the sheet width direction of the sheet conveyed from the sheet discharge outlet 103 in a direction perpendicular to the sheet conveyance direction. Is arranged. As shown in the top view of FIG. 9, the alignment mechanism 30 aligns the left edge of the paper on the processing tray 29 in order to perform alignment based on the center of the paper 33 carried into the processing tray 29 from the paper discharge outlet 103. And a right alignment plate 30R engaged with the right edge of the paper.

  The left and right alignment plates 30L and 30R are fitted and supported in guide grooves (not shown) formed in the processing tray paper mount 29a of the processing tray 29, respectively, and are oriented in a direction orthogonal to the paper transport direction (hereinafter, “ It can be slid and moved in the “paper width direction”. A pair of pulley pairs 111 is arranged along the guide groove on the bottom of the processing tray 29, and a belt 112 is stretched over each pulley pair 111. The left and right alignment plates 30L and 30R are fixed to each belt 112, respectively. Also, shift motors MZ1 and MZ2 are connected to one pulley of each pulley pair 111.

  The left alignment plate 30L and the right alignment plate 30R, which are formed as a pair of left and right in such a configuration, reciprocate in the paper width direction by driving the alignment plate L shift motor MZ1 and the alignment plate R shift motor MZ2. At this time, the alignment plate L shift motor MZ1 and the alignment plate R shift motor MZ2 are synchronized and driven to rotate in the opposite direction by the same amount, so that the sheets carried on the processing tray 29 can be aligned based on the center reference. Become.

"Paper carry-out mechanism"
In the processing tray 29 described above, a pair of reverse rollers 28 that conveys the paper from the paper discharge outlet 103 onto the processing tray paper mounting table 29 a and a scraping roller 104 that sends the paper on the processing tray paper mounting table 29 a to the restriction stopper 105. Is arranged. The reversing roller pair 28 is constituted by a forward / reverse roller that transports the paper sent from the paper discharge port 103 in the reverse transport direction toward the regulation stopper 105 different from the discharge direction after transporting the paper once in the discharge direction. The illustrated reverse roller pair 28 includes a reverse upper roller 28 a positioned above the processing tray 29 and a reverse lower roller 28 b positioned below, and both rollers are configured as a pair of rollers that are pressed against and separated from each other.

  The reverse lower roller 28b has a fixed roller structure embedded in the processing tray paper mount 29a, whereas the reverse upper roller 28a is configured to be movable up and down in the post-processing device housing 21. The reversing upper roller 28 a is attached to a lifting arm that is pivotally supported by the post-processing device housing 21. An actuator such as a solenoid or a motor is connected to the elevating arm to elevate the elevating arm. A reversing roller driving motor 108 (not shown) that can be rotated forward and backward is connected to the reversing upper roller 28a in order to rotate it in the discharging direction and the reversing conveyance direction.

  A control CPU 203 (described later) positions the reversing upper roller 28a at a separated ascending position until the paper leading edge reaches the roller nip position of the reversing roller pair 28 after receiving the paper leading edge detection signal from the paper discharge sensor 102. After the leading edge of the paper reaches the roller nip position, the reverse upper roller 28a is lowered to the operating position where it presses against the reverse lower roller 28b. The reverse upper roller 28a is rotated in the discharge direction until the rear end of the paper is carried out from the paper discharge port 103, and is temporarily stopped and then rotated in the reverse conveyance direction. As a result, the paper discharged from the paper discharge path 22 is first sent in the discharge direction, and the rear end of the paper enters the processing tray 29 from the paper discharge port 103 and then advances in the reverse conveyance direction.

  That is, the control CPU 203, which will be described later, detects the upper end of the reversing upper roller 28a waiting upward at the timing when the front end of the sheet reaches the roller nip position of the pair of reversing rollers 28 after the paper discharge sensor 102 detects the front end of the sheet. And then temporarily stopped after a predetermined amount of rotation in the discharging direction in a state of being pressed against the reverse lower roller 28b, and then rotated in the reverse conveyance direction. In this control, a delay circuit is configured on the basis of a signal for detecting the leading edge of the paper by the paper discharge sensor 102 and a signal for detecting the trailing edge of the paper.

  The take-in roller 104 is constituted by a belt member (not shown) that rotates integrally with the discharge roller pair 25 of the discharge port 103, and hangs down from the discharge roller pair 25 on the uppermost sheet on the processing tray paper mount 29a. Are arranged as follows. The take-in roller 104 rotates in the same direction as the discharge roller pair 25, and applies a conveying force toward the restriction stopper 105 to the paper on the processing tray paper mounting table 29a. The scraping roller 104 is not limited to the rotating belt member, and various mechanisms such as a roller structure that swings up and down and a paddle structure can be employed.

"Eject tray"
The discharge tray 32 is configured with a storage structure having a discharge tray paper mounting surface 32a for stacking and storing paper, and a paper end regulating surface 32b for controlling the end of the paper stacked on the discharge tray paper mounting surface 32a. (See FIG. 2). The discharge tray 32 is provided with the above-described already loaded paper presence / absence sensor 116 (not shown) in order to detect the presence / absence of already loaded paper on the discharge tray 32. The discharge tray paper mounting surface 32a employs a stack structure of either a fixed tray structure with a height fixed from the discharge port 103 or an elevating tray structure that moves up and down according to the amount of paper loaded. The

  The discharge tray paper placement surface 32a has an elevating tray structure. Therefore, a tray mount 32c that can be raised and lowered in the post-processing device housing 21 is supported by the guide rail 106, and a discharge tray 32 having a discharge tray paper mounting surface 32a is fixed to the tray mount 32c. Although the tray mount 32c is not shown in the drawing, for example, a guide rail 106 is disposed on the post-processing device housing 21 so as to be movable up and down, and a belt, a wire, etc. are wound around the tray mount 32c fitted and supported on the rail around a pair of upper and lower pulleys. It is supported by the traction member. Then, the hoisting pulley is rotated by a lifting motor to raise and lower the discharge tray 32 to a predetermined height position.

  As shown in FIG. 2, the discharge tray paper placement surface 32a is formed of an inclined paper placement surface that is inclined so that the downstream side in the discharge direction is high and the upstream side is low. The inclination angle of the discharge tray paper mounting surface 32a is formed to be approximately 40 degrees or more (or 35 degrees or more depending on the paper) although it varies depending on the type of paper to be stacked. If this inclination angle is set large, the paper carried on the discharge tray paper placement surface 32a slides down at a high speed and is abutted against the paper end regulation surface 32b. If this inclination angle is set small, the paper is carried on the discharge tray paper placement surface 32a. The paper carried into the paper gently slides down and hits the paper edge regulating surface 32b. Accordingly, when the inclination angle is set large, it is possible to quickly and surely stack the sheets along the sheet end regulating surface 32b, and to reduce the horizontal dimension (size) of the apparatus.

[Control configuration]
A control configuration of the sheet post-processing apparatus B of the present embodiment will be described with reference to the block diagram of FIG. The control unit 200 of the sheet post-processing apparatus B is connected to the main body control unit 202 of the image forming apparatus A, and the main body control unit 202 is connected to the user operation unit 201 that is also provided in the image forming apparatus A.

  The control unit 200 is computer-controlled by the control CPU 203, copies the control program data stored in the ROM 204 to the RAM 205, and controls the post-processing operation accordingly. In this post-processing operation, not only the corner folding process by the above-described sheet corner folding mechanism 50 but also the sheets stored in the processing tray 29 are accommodated for the sheet 33 that is carried into the sheet post-processing apparatus B and conveyed. The post-processing such as stapling is performed on the bundle, and the post-processed sheet bundle is discharged to the discharge tray 32.

  The control CPU 203 receives paper information (conveyance direction size, paper width direction size, basis weight, etc.), job start signal, and job end signal from the main body control unit 202 of the image forming apparatus A. Upon receiving these information and signals, the control CPU 203 controls the operation of the sheet post-processing apparatus B based on the control program data copied to the RAM 205.

  The control CPU 203 receives a sheet transported from the image forming apparatus A into the transport path 22 and transports it, a sheet alignment control unit 203b, a post-processing control unit 203c, a sheet bundle discharge control unit 203d, And a corner folding control unit 203e for controlling the sheet corner folding mechanism 50. Also in the above-described corner folding process, the control CPU 203 controls the corner folding process of the sheet post-processing apparatus B according to the control program data copied to the RAM 205.

  The transport control unit 203 a controls the transport roller drive motor 109 based on the detection signal of the transport sensor 23 in order to transport the paper transported from the transport inlet 101 through the transport path 22 and discharge it from the paper discharge port 103. Then, the carry-in roller pair 24 and the discharge roller pair 25 are rotated, and before the leading edge of the sheet reaches the path switching flapper 113, the path switching flapper drive motor 115 is controlled to move the path switching flapper 113 to the discharge transport position. To place. Further, the corner folding roller pair 55 located between the carry-in roller pair 24 and the discharge roller pair 25 is also rotated so that the corner folding process of the sheet corner portion can be performed by controlling the conveyance roller drive motor 109 in the same manner.

  When the conveyance control unit 203a determines from the information input from the main body control unit 202 that the sheet 33 conveyed toward the sheet discharge port 103 through the conveyance path 22 is a sheet to be waited at the sheet standby path 27, Based on the paper trailing edge detection signal from the paper discharge sensor 102, the transport roller drive motor 109 is controlled to temporarily stop the discharge roller pair 25. Thereafter, the path switching flapper drive motor 115 is controlled to place the path switching flapper 113 at the standby transport position. Further, the conveyance roller drive motor 109 is controlled to reversely rotate the discharge roller pair 25 so that the paper 33 is switched back and conveyed from the conveyance path 22 toward the paper standby path 27. The timing at which the path switching flapper 113 is switched to the standby transport position is not limited to after the discharge roller pair 25 is temporarily stopped in this way, and the transport control unit 203a switches the path 33 at the rear end in the transport direction. Before reaching the flapper 113, the path switching flapper drive motor 115 may be controlled to place the path switching flapper 113 at the standby conveyance position and guide the paper 33 to the paper standby path 27.

  Further, the conveyance control unit 203a controls the standby roller drive motor 114 to rotate the standby roller pair 26 to feed the paper 33 to the back of the paper standby path 27, stop the rotation of the standby roller pair, and In a state where the sheet is nipped in the sheet waiting path 27. In order to superimpose the waiting paper 33 on the succeeding paper 34 and simultaneously eject it from the paper outlet 103, the transport control unit 203a controls the transport roller drive motor 109 to transport the subsequent paper 34 in the transport direction. However, the standby roller drive motor 114 is controlled based on the detection signal of the leading edge of the succeeding paper 34 from the carry-in sensor 23, and the standby roller pair 26 is rotated to send the paper 33 from the paper standby path 27 to the transport path 22.

  When stacking the paper 33 transported along the transport path 22 on the processing tray 29, the reversing upper roller 28a waits at a raised position separated from the reversing lower roller 28b, and the leading end of the transported paper 33 is the reversing roller. After passing through the nip position of the pair 28, the elevating motor 110 is controlled so that the reverse upper roller 28a is lowered and brought into pressure contact with the reverse lower roller 28b. Further, the reversing roller pair 28 rotates so as to convey the paper in the discharge direction until the rear end of the conveyed paper 33 passes through the paper discharge sensor 102, and when the paper discharge sensor 102 detects the rear edge of the paper, The paper is transported toward the regulating stopper 105 (in the direction opposite to the discharge direction) by once reversely rotating after stopping the rotation. The reverse roller pair 28 is rotated by controlling the reverse roller drive motor 108.

  The sheet 33 conveyed toward the restriction stopper 105 by the reverse roller pair 28 is conveyed to the restriction stopper 105 by the scraping roller 104 and stacked on the processing tray 29. The pick-up roller 104 is driven by the transport roller drive motor 109 in the same manner as the discharge roller pair 25.

  When the paper 33 is discharged from the paper discharge port 103 and is not directly stored in the processing tray 29 but is directly discharged to the discharge tray 32, the reversing upper roller 28a is kept in the raised position and is transported through the transport path 22. The elevating motor 110 is controlled so that the reversing upper roller 28a is lowered and pressed against the reversing lower roller 28b at the timing when the leading edge of the paper 33 to be discharged exits the paper discharge port 103 and reaches the nip position of the reversing upper roller 28a . Thereafter, the pair of reversing rollers 28 is rotated in the discharge direction without being temporarily stopped or reversely rotated, and the sheets are stacked on the discharge tray 32 from the discharge outlet 103.

  The sheet alignment control unit 203b operates the alignment plates 30R and 30L by controlling the driving of the alignment plate L shift motor MZ1 and the alignment plate R shift motor MZ2. This alignment operation is performed based on a trailing edge detection signal of the paper 33 conveyed by the paper discharge sensor 102. Further, the sheet alignment control unit 203b does not perform the alignment operation when the sheet 33 conveyed by the conveyance control unit 203a is directly discharged to the discharge tray 32.

  The post-processing control unit 203c controls the staple unit 31 when stapling a bundle of sheets. When the job end signal is received from the main body control unit 202, the post-processing control unit 203c is activated by the drive motor of the staple unit 31 after the last sheet is stored in the processing tray 29 and the sheet bundle is aligned in the sheet width direction. Send a signal. Upon receipt of this activation signal, the staple unit 31 executes a binding operation, and sends an end signal to the post-processing control unit 203c after the binding operation is completed. The post-processing control unit 203c receives the end signal, recognizes that the binding operation is completed, and notifies the sheet bundle discharge control unit 203d.

  Upon receipt of the binding operation completion notification from the post-processing control unit 203c, the sheet bundle discharge control unit 203d presses the sheet bundle on the processing tray 29 with the reverse roller pair 28 and conveys the sheet bundle in the direction of the discharge tray 32. Therefore, the reverse roller driving motor 108 is driven. By this operation, the sheet bundle on the processing tray 29 is conveyed and stacked on the discharge tray 32 on the downstream side.

  When the corner folding control unit 203e receives from the main body control unit 202 an instruction for corner folding processing (up-folding processing, down-folding processing, no processing) input by the user through the user operation unit 201, the paper corner control unit 203e responds to the instruction. The folding mechanism 50 is controlled. When the corner folding process is performed on the conveyed paper 33, the corner folding control unit 203 e controls the corner folding flapper motor 206 based on the detection signal at the leading edge of the sheet by the carry-in sensor 23, and the upper flapper 51 and the lower flapper 52. Is swung from the horizontal position. When the corner folding process is not performed, the corner folding control unit 203e does not control the sheet corner folding mechanism 50. Accordingly, the upper flapper 51 and the lower flapper 52 are maintained in the horizontal position.

  Further, the main body control unit 202 not only forms an image in the image forming apparatus A, but also instructs a corner folding process input from the user operation unit 201 in connection with a sheet corner folding process performed by the sheet post-processing apparatus B. Based on the detection signal from the already loaded paper presence / absence sensor 116 input via the control CPU 203, image formation on the paper and output of the paper to the paper post-processing apparatus B are controlled. Specifically, as described above in relation to the simultaneous paper discharge operation, when the first paper is set to be folded down at the corners, the paper surface is turned upside down to form an image on the paper and the paper The process of changing the output order of the sheet, the process of not continuously folding the two sheets of paper, and the process of carrying out an additional sheet not to form an image in order to discharge simultaneously with the last sheet of which the corner is folded upward is controlled. .

  In the following, a process of setting an instruction of a sheet corner folding process executed by the sheet corner folding mechanism 50 by the user operation unit 201 in the control configuration of the above-described embodiment will be described based on a flowchart of FIG.

  First, in step S101, an instruction for corner folding processing is received.

  Next, in step S102, the instruction for the corner folding process is prohibited for the two sheets conveyed immediately before and after the sheet for which the corner folding process is instructed in step S101. As described above, this is a setting for preventing the two sheets from being subjected to the corner folding process in order to simultaneously discharge the sheet subjected to the corner folding process and the sheet not to the corner folding process from the conveyance path 22.

  In step S103, it is determined whether there is an additional corner folding instruction. This determination is made based on information input from the user operation unit 201 by the user. If there is an instruction for additional corner folding processing, the process returns to step S101, and if not, the process proceeds to step S104.

  In step S <b> 104, it is determined whether or not the corner folding process instruction input by the user operation unit 201 includes a lower folding process for the first sheet to be carried out to the sheet post-processing apparatus B. If an instruction for folding down the first sheet is instructed, the process proceeds to step S105, and if not, the process proceeds to step S107.

  In step S105, it is determined whether or not there are sheets stacked on the discharge tray 32 of the sheet post-processing apparatus B. This determination is made based on the detection signal of the already loaded paper presence / absence sensor 116 input via the control CPU 203. If there is a sheet loaded on the discharge tray 32, the process proceeds to step S106, and if not, the process proceeds to step S107.

  In step S106, the paper surface of the paper on which the image is formed in the image forming apparatus A is reversed, and the order of the papers output to the paper post-processing apparatus B after the image formation is changed. This step is performed to prevent the first sheet carried out to the sheet post-processing apparatus B from being folded downward.

  Next, in step S <b> 107, it is determined whether or not the corner folding process instruction input by the user operation unit 201 includes an upper folding process for the last sheet to be carried out to the sheet post-processing apparatus B. If there is an instruction for the upper folding process on the last sheet, the process proceeds to step S108, and if not, the setting of the corner folding process is ended.

  In step S108, the image forming apparatus A is set to the sheet post-processing apparatus B so that a sheet on which image formation is not performed is carried out after the last sheet. After this step, the setting of the corner folding process is terminated.

  Further, a process of performing the corner folding process and the conveyance of the sheet based on the setting of the corner folding process input by the user operation unit 201 in the sheet post-processing apparatus B of the present embodiment will be described based on the flowchart of FIG. .

  In step S201, the paper is carried from the image forming apparatus A to the paper post-processing apparatus B. The paper discharged from the paper discharge port 13 of the image forming apparatus A is carried in from the carry-in port 101 of the paper post-processing apparatus B, the leading end thereof is detected by the carry-in sensor 23, and the paper is conveyed along the conveyance path 22 by the carry-in roller pair 24. It is conveyed downstream in the direction.

  In the next step S202, the corner folding process is performed on the sheet 33 conveyed on the conveyance path 22. The sheet 33 is subjected to corner folding processing by the sheet corner folding mechanism 50 while being transported by the carry-in roller pair 24 based on a corner folding processing instruction input by the user operation unit 201.

  In step S203, it is determined whether or not the conveyed paper sheet 33 has an upward corner fold. If there is an upward corner fold, the process proceeds to step S204, and if not, the process proceeds to step S205.

  In step S <b> 204, the transported paper 33 is made to wait on the paper standby path 27. The conveyance control unit CPU 203a controls the conveyance roller drive motor 109, the standby roller drive motor 114, and the path switching flapper drive motor 115, and switches the sheet 33 from the conveyance path 22 to the sheet standby path 27 so as to wait.

  In step S205, it is determined whether or not the sheet 33 to be conveyed has a downward corner folding portion. If the sheet 33 has a downward corner fold, the process proceeds to step S207, and if not, the process proceeds to step S206.

  In step S <b> 206, it is determined whether or not there is an instruction for a downward folding process on the sheet conveyed next along the conveyance path 22. If there is an instruction for the folding process, the process proceeds to step S204, and if not, the process proceeds to step S209.

  In step S207, it is determined whether the sheet 33 transported along the transport path 22 is the first sheet or the second and subsequent sheets. If the sheet 33 is the first sheet, the process proceeds to step S210. If the sheet 33 is the second sheet or later, the process proceeds to step S208.

  In step S <b> 208, the paper 33 whose corners are folded downward and the preceding paper that is not waiting for corner folding in the paper standby path 27 are simultaneously discharged from the paper discharge outlet 13 of the transport path 22. At this time, the sheet 33 is overlapped with the preceding sheet in the transport path 22 so that the leading end of the corner of the sheet 33 does not precede the leading end of the preceding sheet sent from the sheet standby path 27.

  In step S209, it is determined whether or not the sheet whose corner has been folded upward is waiting on the sheet waiting path 27. If the upper folded paper is waiting on the paper standby path 27, the process proceeds to step S211. If not, the process proceeds to step S210.

  In step S <b> 210, since there is no sheet on the sheet standby path 27, the sheet conveyed next on the conveyance path 22 is discharged as it is from the sheet discharge outlet 13 of the conveyance path 22.

  In step S <b> 211, the paper 33 that has been folded upward on the paper standby path 27 and the subsequent paper that is transported on the transport path 22 are simultaneously discharged from the paper discharge outlet 13 of the transport path 22. At this time, the sheet 33 is sent out from the sheet standby path 27 so that the leading end of the corner portion of the sheet 33 that is folded upward does not precede the leading end of the succeeding sheet that is conveyed along the conveying path 22. It is superimposed on the following paper.

  In the next step S212, it is determined whether there is a sheet to be carried into the sheet post-processing apparatus B next. If there is a sheet to be carried next, the process proceeds to step S201, and if not, the sheet conveyance is terminated. Next, the control CPU 203 determines whether there is a sheet to be carried in based on a job end signal received from the main body control unit 202.

  As mentioned above, although this invention was demonstrated in relation to preferred embodiment, this invention is not limited to the said embodiment, In the technical scope, it can implement by adding various change or deformation | transformation. Needless to say.

A Image forming apparatus B Paper post-processing device 21 Device housing 22 Transport path 23 Paper carry-in sensor 24 Carry-in roller pair 25 Discharge roller pair 26 Waiting roller pair 27 Paper wait path 28 Reverse roller pair 29 Processing tray 32 Discharge tray 33 Paper 34 Subsequent paper 50 Paper corner folding mechanism 51 Upper flapper 52 Lower flapper 53 Upper paper guide 54 Lower paper guide 55 Folding roller pair 101 Carry-in port 103 Paper discharge port 113 Path switching flapper 201 User operation unit 202 Main body control unit 203 Control CPU
203a Conveyance control unit 203b Paper alignment control unit 203c Post-processing control unit 203d Paper bundle discharge control unit 203e Corner folding control unit

Claims (10)

A paper transport path for transporting paper,
A transport mechanism for transporting paper along the paper transport path;
A corner folding processing mechanism for corner-folding at least one corner of the leading edge of the sheet conveyed in the predetermined conveying direction by the conveying mechanism to one surface side of the sheet;
The preceding sheet transported downstream from the corner folding mechanism in the transport direction is temporarily retracted to a standby position for retracting from the sheet transport path, and the preceding sheet is temporarily retracted from the sheet transport path. A paper standby mechanism for returning the paper from the standby position to the paper transport path;
A control unit for controlling operations of the transport mechanism, the corner folding processing mechanism, and the paper standby mechanism;
The controller, when returning the preceding sheet, which has been folded by the corner folding processing mechanism, from the standby position to the sheet conveyance path, on the one surface side where the preceding sheet has been folded, The paper transport device, wherein the paper standby mechanism is operated so as to overlap a subsequent paper that is not folded in a corner and transported by the transport mechanism following the preceding paper in the paper transport path. A paper transport path for transporting paper,
A transport mechanism for transporting paper along the paper transport path;
A corner folding processing mechanism for corner-folding at least one corner of the leading edge of the sheet conveyed in the predetermined conveying direction by the conveying mechanism to one surface side of the sheet;
The preceding sheet transported downstream from the corner folding mechanism in the transport direction is temporarily retracted to a standby position for retracting from the sheet transport path, and the preceding sheet is temporarily retracted from the sheet transport path. A paper standby mechanism for returning the paper from the standby position to the paper transport path;
A control unit for controlling operations of the transport mechanism, the corner folding processing mechanism, and the paper standby mechanism;
The controller, when returning the preceding sheet that has not been folded by the corner folding processing mechanism from the standby position to the sheet transport path, follows the preceding sheet and is transported by the transport mechanism. The sheet standby mechanism is operated so that the sheet folded by the corner folding processing mechanism overlaps the preceding sheet and the sheet conveyance path on the one surface side of the corner folded. Conveying device.   When the preceding sheet is folded by the corner folding processing mechanism and discharged from the sheet conveying path with the one surface facing the sheet placing surface, the control unit preliminarily ejects the sheet placing surface. Detecting that there is no other sheet, the control unit controls the transport mechanism so that the preceding sheet is retreated to the standby position and is discharged from the sheet transport path without being overlapped with the succeeding sheet. The sheet conveying apparatus according to claim 1, wherein   The control unit performs the corner folding process so that the preceding sheet is folded when the one side of the sheet to be folded is opposite to the one side of the sheet where the standby position is provided. And a mechanism for controlling the sheet standby mechanism so that the preceding sheet folded in a corner is retracted to the standby position and overlapped with the succeeding sheet that is not folded in the sheet conveyance path. The sheet conveying apparatus according to claim 1 or 3.   The control unit performs the corner folding process so that the subsequent sheet is folded when the one side of the sheet to be folded is the same side as the one side of the sheet provided with the standby position. And a mechanism for controlling the sheet standby mechanism so that the preceding sheet that has not been folded is retracted to the standby position and overlapped with the succeeding sheet that has been folded in the sheet conveyance path. The sheet conveying device according to claim 2.   2. The control unit according to claim 1, wherein the control unit controls the transport mechanism so that the preceding sheet and the succeeding sheet overlapped in the sheet transport path are simultaneously discharged from the sheet transport path. The sheet post-processing apparatus according to any one of claims 1 to 5.   The control unit is configured to prevent the preceding sheet or the succeeding sheet from being folded in a corner so that a leading end thereof does not precede the leading end of the succeeding sheet or the preceding sheet that is not folded in a corner. The paper transport device according to claim 1, wherein the paper standby mechanism is controlled to return the paper from the standby position to the paper transport path.   The corner folding processing mechanism includes a sheet corner guiding section that causes at least one corner of the leading edge of the sheet conveyed along the sheet conveying path by the conveying mechanism to bend outward with respect to the conveying direction; and the sheet 8. A sheet corner folding processing section that comprises a sheet corner folding processing section that presses the corner of the sheet that has been warped back while being transported by the transport mechanism in the transport direction. Paper post-processing equipment.   9. The paper standby mechanism according to claim 1, wherein the standby position is provided to be branched from the paper transport path on one side of the paper transported through the paper transport path. The paper post-processing device as described. An image forming unit for forming an image on paper;
A paper post-processing device that performs a corner folding process on the paper sent from the image forming unit,
The image forming system according to claim 1, wherein the sheet post-processing apparatus is the sheet post-processing apparatus according to claim 1.

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