Sheet folding device and sheet post-processing device equipped with same

Abstract

To provide a sheet folding device which restricts a sheet from contacting a folding roller pair, and which has a small number of components and a control mechanism capable of being simplified, and to provide a sheet post-processing apparatus including the sheet folding device.SOLUTION: A sheet folding device includes: a folding roller pair 64 for causing a sheet to pass through a nip part so as to fold the sheet into two, and conveying the sheet in a first direction; a folding blade 67 for pushing a folded portion of the sheet into the nip part to perform folding processing; and a sheet guide which extends in a second direction orthogonal to the first direction on an upstream side of the folding roller pair relative to the first direction. The folding blade has: an oscillation support shaft; a blade part 67b oscillating about the oscillation support shaft, and being selectively placed at a folding position and a retreat position; and a pair of arm parts 67c coupling the blade part to the oscillation support shaft. The sheet guide is capable of passing through between the pair of arm parts. In a state of being placed at the retreat position, the blade part forms, between itself and the sheet guide, a shunt path 73 through which the sheet can pass.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sheet folding device that performs folding processing on sheets such as paper on which an image has been formed by an image forming device such as a copying machine or a printer, and a sheet post-processing device equipped with the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, sheet post-processing devices have been used that include a sheet folding device that performs folding processing on paper (sheets) on which images have been formed by an image forming device such as a copying machine or a printer.

[0003] A known sheet folding device includes a folding roller pair consisting of two folding rollers and a folding blade that can move forward and backward with respect to a nip portion of the folding roller pair. In this sheet folding device, the folding blade bends a predetermined portion of the paper and pushes it into the nip portion of the folding roller pair, and the nip portion of the folding roller pair presses the paper, thereby folding the paper.

[0004] For example, when folding a sheet of paper in half, the center of the sheet is aligned with the nip of the pair of folding rollers, and when folding a sheet of paper in thirds, one-third of the sheet is aligned with the nip of the pair of folding rollers, and the folding blade is pushed in from the opposite direction to the folding rollers of the sheet.

[0005] There are two methods for pushing the folding blade in: one is to move the folding blade back and forth against the paper, and the other is to rotate the folding blade to push it in. The method of rotating the folding blade to push the paper in requires fewer parts and simplifies the configuration.

[0006] For example, Patent Document 1 discloses a method for folding a sheet using a fixing roller pair, and discloses an image forming device having a first conveying path that guides a sheet to the fixing roller pair, a second conveying path that guides a sheet on which a toner image has been fixed by the fixing roller pair to the first conveying path, a third conveying path that branches off from the first conveying path between the secondary transfer unit and the fixing roller pair and guides the sheet to the second conveying path, and a switching member that switches the conveying destination of the sheet to either the fixing roller pair or the third conveying path.

[0007] When folding the sheet, a switching member provided at the branch point of the first and third conveying paths rotates and acts as a folding blade to push the loop (warping) of the sheet into the nip portion of the fixing roller pair. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2017-132572 A Summary of the Invention [Problem to be solved by the invention]

[0009] When the folding blade is driven to rotate as in Patent Document 1, in order to push the folding blade from the opposite side of the folding direction, the pivot of the folding blade needs to be located on the same side as the folding blade across the paper. In other words, since the pivot of the folding blade is located on the opposite side of the folding roller across the paper, it is difficult to make the path of the folding blade's rotation perpendicular to the paper when pushing the paper. This causes a problem that the paper cannot be pushed into the nip of the folding rollers with good accuracy. In addition, there is a problem that the folding blade cannot be made large because of the large restrictions on the installation position of the folding blade due to the component configuration, and the paper is not pushed in sufficiently.

[0010] In view of the above problems, the present invention aims to provide a sheet folding device and a sheet post-processing device equipped with the same, which can stabilize the rotation trajectory of the folding blade when rotating the folding blade to fold the sheet, and also increase the freedom of the installation position of the folding blade. [Means for solving the problem]

[0011] In order to achieve the above object, a first configuration of the present invention is a sheet folding device including a pair of folding rollers, a folding blade, and a sheet guide. The pair of folding rollers folds the sheet in two by passing the sheet through a first nip portion and transports the sheet in a first direction. The folding blade is disposed opposite the pair of folding rollers and pushes the folded portion of the sheet into the first nip portion in the first direction to perform a folding process. The sheet guide is disposed in a sheet transport path extending along a second direction intersecting with the first direction on the upstream side of the pair of folding rollers with respect to the first direction. The folding blade has a swinging support shaft, a blade portion, and a pair of arm portions. The swinging support shaft is disposed on the same side as the pair of folding rollers with respect to the sheet transport path in the first direction, and is parallel to the axis of the pair of folding rollers. The blade portion swings about the swinging support shaft and is selectively disposed at a folding position where the sheet is pushed into the nip portion to perform a folding process, and a retreated position where the blade portion retreats from the folding position to the opposite side of the pair of folding rollers across the sheet transport path. The pair of arms connects both axial ends of the blade to the swing support shaft. The sheet guide can pass between the pair of arms when the blade moves between the folding position and the retracted position. When the blade is disposed at the retracted position, the sheet guide forms a retreat path between the blade and the sheet guide, through which the sheet can pass. Effect of the Invention

[0012] According to the first configuration of the present invention, the pivot shaft of the folding blade is located on the same side as the pair of folding rollers with respect to the sheet to be folded. Therefore, the movement trajectory of the blade when pushing the sheet into the nip portion can be made substantially perpendicular to the sheet, and the sheet can be pushed into the nip portion with high precision. In addition, when the folding blade is placed in the retreat position, an escape path is formed between the sheet guide and the blade portion. Therefore, even if the pivot shaft of the folding blade and the blade portion are placed on opposite sides of the sheet, an escape path for the sheet can be secured, and the degree of freedom in the placement position of the folding blade is increased. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of an image forming system including a sheet post-processing device 30 having a first sheet folding unit 60 according to an embodiment of the present invention, and an image forming device 10 to which the sheet post-processing device 30 is connected. [Diagram 2] FIG. 1 is a side cross-sectional view showing an internal configuration of an image forming apparatus 10 to which a sheet post-processing device 30 having a first sheet folding unit 60 of the present embodiment is connected. [Diagram 3] FIG. 1 is a side cross-sectional view showing an internal configuration of a sheet post-processing device 30 including a first sheet folding unit 60 according to an embodiment of the present invention. [Figure 4] FIG. 1 is a cross-sectional view showing the structure around the first paper folding unit 60 of the present embodiment, showing a state in which the folding blade 67 is disposed at the retreated position and the movable guide 69 is disposed at the cover position. [Diagram 5] FIG. 13 shows a state in which the folding blade 67 is located at the folding position and the movable guide 69 is located at the release position when folding the sheet S in half by the first sheet folding unit 60. [Figure 6] FIG. 13 shows a state in which the folding blade 67 is located at the retreat position and the movable guide 69 is located at the cover position when folding the sheet S in thirds by the first sheet folding unit 60. [Figure 7] FIG. 13 shows a state in which the folding blade 67 is located at the folding position and the movable guide 69 is located at the release position when folding the sheet S in thirds by the first sheet folding unit 60. [Figure 8] FIG. 1 is a perspective view showing a drive mechanism 90 for a folding blade 67 and a movable guide 69 of a first paper folding unit 60 of the present embodiment, in which the folding blade 67 is in a retracted position and the movable guide 69 is in a cover position. [Figure 9] FIG. 1 is a perspective view showing a drive mechanism 90 for a folding blade 67 and a movable guide 69 of a first paper folding unit 60 according to the present embodiment, in which the folding blade 67 is in a folding position and the movable guide 69 is in a release position. [Figure 10] FIG. 11 is a cross-sectional view showing a structure around a first paper folding unit 60 according to a modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of an image forming system including a paper post-processing device 30 equipped with a first paper folding unit 60 according to one embodiment of the present invention, and an image forming device 10 to which the paper post-processing device 30 is connected. Fig. 2 is a side cross-sectional view showing the internal configuration of the image forming device 10 to which the paper post-processing device 30 is connected. Fig. 3 is a side cross-sectional view showing the internal configuration of the paper post-processing device 30 equipped with the first paper folding unit 60.

[0015] As shown in Fig. 1, the image forming apparatus 10 prints an image on a paper (sheet) based on image data input from the outside via a network communication unit (not shown) or image data read by an image reading unit 11 arranged on the upper part of the image forming apparatus 10. As shown in Fig. 2, the image forming apparatus 10 includes a paper feed unit 15 that feeds paper, an image forming unit 18 that forms a toner image on the paper, a fixing unit 19 that fixes the toner image on the paper, a pair of discharge rollers 23 and 24 that transport the paper after fixing and discharge it to a paper discharge unit 21 and a paper post-processing device 30, respectively, and a main body control unit 100. The main body control unit 100 controls the operation of the image forming apparatus 10, and is configured to be able to communicate with a post-processing control unit 101 (described later) of the paper post-processing device 30, and controls the post-processing control unit 101.

[0016] The paper post-processing device 30 is used in connection with the image forming device 10, and performs post-processing such as punch hole formation, binding, and folding on the paper transported from the image forming device 10. Note that the paper post-processing device 30 is not limited to a device that performs post-processing on paper automatically transported from the image forming device 10, but may be a device that transports paper set by a user on a tray (not shown) to a position where the paper can be post-processed by itself, and performs post-processing on the paper.

[0017] 3, the paper post-processing device 30 includes a punch hole forming device 33 that performs a predetermined punching process on the paper, a staple unit 35 that stacks and staples a plurality of sheets of paper, a first paper folding unit 60 that performs a folding process on the paper, and a second paper folding unit 80. The paper post-processing device 30 also includes a paper entrance 36 through which paper discharged from the discharge section 7 (see FIG. 2) of the image forming device 10 is carried in, a main discharge tray 38 that receives paper discharged from a main discharge opening 37, a sub-discharge tray 40 that receives paper discharged from a sub-discharge opening 39, a post-processing control unit 101 that controls the entire paper post-processing device 30, various switching members, various rollers, etc.

[0018] The paper entrance 36 and the main discharge opening 37 are connected to each other via a first transport path 42. A second transport path 43 branching off from the first transport path 42 is connected to the sub-discharge opening 39. A third transport path 44 branching off from the first transport path 42 is connected to a second paper folding unit 80.

[0019] The paper carried in through the paper entrance 36 is sent downstream (to the left in FIG. 3) along the first transport path 42. A main discharge roller pair 47 is provided at the downstream end of the first transport path 42 to send the paper to the main discharge tray 38. When sending the paper to the staple unit 35, the main discharge roller pair 47 is configured to separate and release the nip. The main discharge tray 38 mainly receives a stack of papers that have been stapled by the staple unit 35. Note that the main discharge tray 38 may also receive papers that have not been subjected to post-processing or that have only been subjected to punching.

[0020] At the downstream end of the second transport path 43, a sub-discharge roller pair 48 is provided which sends the paper to the sub-discharge tray 40. The sub-discharge tray 40 mainly receives paper discharged without being subjected to post-processing by the post-processing device 30, paper that has been subjected to only punching processing by the punch hole forming device 33, and paper that has been subjected to only folding processing by the first paper folding unit 60.

[0021] The punch hole forming device 33 is disposed above and facing the first transport path 42, between the paper entrance 36 and the first paper folding unit 60. The punch hole forming device 33 performs a punching process on the paper transported on the first transport path 42 at a predetermined timing.

[0022] The staple unit 35 is disposed downstream of and below the first transport path 42. The staple unit 35 performs a stacking process for stacking a plurality of sheets of paper to form a paper bundle, and also performs a binding process for binding the stacked paper bundle with staples.

[0023] The first paper folding unit 60 is disposed immediately upstream of the branching portion of the first conveying path 42 and the second conveying path 43. The first paper folding unit 60 performs folding processing on the paper, for example, when a user selects folding processing for one sheet of paper. A detailed configuration of the first paper folding unit 60 will be described later.

[0024] The second paper folding unit 80 is provided below the paper post-processing device 30, downstream of the third transport path 44. The second paper folding unit 80 folds the paper stack when, for example, a user selects folding processing for a paper stack consisting of multiple sheets of paper. Provided downstream of the second paper folding unit 80 are a lower discharge opening 85 that discharges the paper stack that has been folded by the second paper folding unit 80, and a lower discharge tray 87 that receives the paper stack discharged from the lower discharge opening 85.

[0025] Figures 4 and 5 are partial enlarged views of the periphery of first paper folding unit 60 in Figure 3. Below, a detailed description is given of the configuration of first paper folding unit 60. As shown in Figure 4, first paper folding unit 60 includes a folding roller pair 64, a first transport roller pair 65, a folding blade 67, a fixed guide 68, and a movable guide 69.

[0026] The pair of folding rollers 64 is composed of a first roller 63a and a second roller 63b. The second roller 63b is pressed against the first roller 63a with a predetermined pressure by a first pressing mechanism 70 to form a first nip portion N1. The sheet S that passes through the first nip portion N1 is transported from right to left in FIG. 4 (first direction).

[0027] The first transport roller pair 65 is composed of a first roller 63a and a third roller 63c. The third roller 63c is pressed against the first roller 63a with a predetermined pressure by a second pressing mechanism 71 to form a second nip portion N2. The paper S that passes through the second nip portion N2 is transported in a direction from top to bottom in FIG. 4 (a second direction) that intersects with the first direction.

[0028] The second roller 63b is in pressure contact with the first roller 63a on the downstream side (lower side in FIG. 4) in the conveying direction (second direction) of the paper S by the first conveying roller pair 65. The first roller 63a, the second roller 63b, and the third roller 63c are arranged so that their rotation centers are not aligned on the same straight line. In other words, the first roller 63a and the second roller 63b, and the first roller 63a and the third roller 63c are in pressure contact with each other such that the straight lines connecting the rotation centers form a predetermined angle.

[0029] Further, a fourth roller 63d is pressed against the third roller 63c to form a second conveying roller pair 66. The fourth roller 63d is composed of two rollers divided in the axial direction (direction perpendicular to the paper surface of FIG. 4), and each is pressed against both axial ends of the third roller 63c. A switching guide 72 is disposed between the two fourth rollers 63d. When the sheet S is not to be folded, the switching guide 72 is retracted upward (to the broken line position), so that the sheet S is conveyed horizontally along the first conveying path 42, passes through the second conveying path 43, and is discharged to the sub-discharge tray 40 (see FIG. 3 for both).

[0030] The folding blade 67 has a swinging support shaft 67a, a blade portion 67b, and an arm portion 67c. The swinging support shaft 67a is provided parallel to the axis of the folding roller pair 64 on the same side (left side in FIG. 4) as the folding roller pair 64 with respect to the transport path of the paper S, and is swingably supported by the first frame 93a of the paper post-processing device 30. The blade portion 67b is disposed on the opposite side (right side in FIG. 4) to the folding roller pair 64 across the transport path of the paper S. The arm portion 67c connects both ends of the blade portion 67b in the axial direction to the swinging support shaft 67a. The blade portion 67b is selectively disposed at a folding position (see FIG. 5) where the paper S is pushed into the second nip portion N2 to perform folding processing, and at a retreat position (see FIG. 4) where the blade portion 67b is retreated from the folding position. When the blade portion 67b is disposed at the retreat position, a retreat path 73 for the paper S is formed between the movable guide 69 described later and the blade portion 67b.

[0031] The fixed guide 68 and the movable guide 69 are disposed upstream of the pair of folding rollers 64 in the first direction, and guide the sheet S that has passed through the second nip portion N2. The fixed guide 68 is fixed between the conveying roller 63 and the folding blade 67. The movable guide 69 is disposed between the swinging support shaft 67a and the blade portion 67b of the folding blade 67, and forms a retreat path 73 together with the inner surface of the blade portion 67b. The movable guide 69 can reciprocate between a cover position (see FIG. 4) that covers an area of ​​the outer circumferential surface of the second roller 63b that faces the conveying path, and a release position (see FIG. 5) that moves from the cover position to expose the outer circumferential surface of the second roller 63b. The movable guide 69 can pass between the pair of arm portions 67c when the blade portion 67b moves between the folding position and the retreat position.

[0032] Next, the folding process (operation) of the sheet S by the first sheet folding unit 60 will be described with reference to Fig. 4 and Fig. 5 to Fig. 7. The folding process of the sheet S is executed by the post-processing control unit 101 (see Fig. 3) provided in the sheet post-processing device 30 when the folding mode is selected by the user using the operation panel 12 (see Fig. 2) of the image forming device 10. Also, the fourth roller 63d and the switching guide 72 are omitted from Figs. 5 to 7.

[0033] First, a case where the sheet S is folded in half will be described. As shown in Fig. 4, the sheet S conveyed from the first conveying path 42 has its conveying direction switched to downward by the switching guide 72. As a result, the sheet S is conveyed along the outer circumferential surface of the third roller 63c, passes through the second nip portion N2 of the first conveying roller pair 65, and further passes between the fixed guide 68 and the movable guide 69 to enter the retreat path 73. Then, the conveyance of the sheet S is stopped so that the folding position of the sheet S (the center portion in the sheet conveying direction) faces the first nip portion N1.

[0034] The timing to stop the transport of the paper S is determined based on the detection timing of the paper detection sensor 75 (see FIG. 3). Specifically, when the paper detection sensor 75 detects the leading edge of the paper S, the detection result is sent to the post-processing control unit 101. The post-processing control unit 101 stops the transport of the paper S a predetermined time after the leading edge of the paper S is detected. The time from when the leading edge of the paper S is detected to when the transport of the paper S is stopped is set in advance for each size of the paper S.

[0035] 5, the movable guide 69 is moved to the release position, and the folding blade 67 is swung counterclockwise to the folding position. At this time, the blade portion 67b of the folding blade 67 comes into contact with the folding position of the sheet S. The sheet S pushed out by the blade portion 67b is pushed into the first nip portion N1 of the folding roller pair 64 in a bent state. A fold F is formed in the sheet S that has passed through the first nip portion N1.

[0036] The sheet S with the crease F formed thereon passes through the second transport path 43 and is discharged from the sub discharge opening 39 (the sub discharge roller pair 48) to the sub discharge tray 40. Thereafter, the movable guide 69 is moved to the cover position and the folding blade 67 is moved to the retracted position to return to the state shown in FIG. 4. Thereafter, the sheet S is folded in half in the same manner.

[0037] Next, a case where the sheet S is folded in thirds (Z-fold) will be described. In the third-fold process, first, the switching guide 72 (see FIG. 4) is retracted upward, and the leading edge of the sheet S conveyed along the first conveying path 42 is stopped downstream of the second nip portion N2 (left side in FIG. 6) so that the first folding position of the sheet S (1 / 3 position from the leading edge of the sheet) faces the second nip portion N2. The timing at which the conveyance of the sheet S is stopped is determined based on the detection timing of a sheet detection sensor (not shown) arranged along the first conveying path 42.

[0038] Next, the switching guide 72 is moved downward. At this time, the switching guide 72 comes into contact with the first folding position of the sheet S. The sheet S pushed out by the switching guide 72 is pushed into the second nip portion N2 of the first transport roller pair 65 in a bent state, as shown in FIG. 6. A fold F1 is formed in the sheet S that has passed through the second nip portion N2. The first transport roller pair 65 functions as a folding roller pair when folding the sheet in three.

[0039] Thereafter, sheet S passes from fold F1 through second nip portion N2, and then passes between fixed guide 68 and movable guide 69 to enter retreat path 73. Then, transport of sheet S is stopped so that the second folding position of sheet S (position 2 / 3 of the way from the leading edge of sheet S) faces first nip portion N1. The timing at which transport of sheet S is stopped is determined based on the detection timing of sheet detection sensor 75.

[0040] 7, the movable guide 69 is moved to the release position, and the folding blade 67 is swung counterclockwise to the folding position. At this time, the blade portion 67b of the folding blade 67 comes into contact with the second folding position of the sheet S. The sheet S pushed out by the blade portion 67b has both the leading edge and the bent portion of the sheet S pushed into the first nip portion N1 of the folding roller pair 64. A fold F2 is formed in the sheet S that has passed through the first nip portion N1.

[0041] The sheet S with the folds F1 and F2 formed thereon passes through the second transport path 43 and is discharged from the sub discharge opening 39 (the sub discharge roller pair 48) to the sub discharge tray 40. Thereafter, the movable guide 69 is moved to the cover position, the folding blade 67 is moved to the retracted position, and the switching guide 72 is retracted upward. Thereafter, the sheet S is folded in three in the same manner.

[0042] Figures 8 and 9 are perspective views showing a drive mechanism 90 for the folding blade 67 and movable guide 69 of the first paper folding unit 60 of this embodiment. Figure 8 shows a state in which the folding blade 67 is in the retracted position and the movable guide 69 is in the covered position, while Figure 9 shows a state in which the folding blade 67 is in the folding position and the movable guide 69 is in the released position. Note that Figures 8 and 9 show the configuration of one end side (the rear side of the paper in Figures 4 and 5) of the folding blade 67 and the movable guide 69, but the configuration of the other end side is similar except that the drive input gear 76 is not provided.

[0043] The drive mechanism 90 has a drive input gear 76, a first gear portion 67c, a link member 78, and a drive motor 91 (see FIG. 3). The drive input gear 76 is fixed to the swing support shaft 67a of the folding blade 67, and inputs the drive force from the drive motor 91 to the swing support shaft 67a. A first gear portion 67c is formed in an arc shape on the outer circumferential surface of the swing support shaft 67a along a part of the circumferential direction.

[0044] The link member 78 has a base portion 78a, a rotating shaft 78b formed at one end of the base portion 78a, an engaging boss 78c formed at the other end of the base portion 78a, and a second gear portion 78d formed on the outer circumferential surface of the rotating shaft 78b. The link member 78 is rotatably supported by the second frame 93b via the rotating shaft 78b. The engaging boss 78c engages with the engaged portion 69a of the movable guide 69. The second gear portion 78d meshes with the first gear portion 67c.

[0045] When the drive input gear 76 is rotated a predetermined angle in the clockwise direction (positive direction) from the state shown in Figure 8 by the drive motor 91, the folding blade 67 together with the oscillating support shaft 67a also rotates a predetermined angle in the clockwise direction (positive direction) in Figure 8, and is positioned in the folding position shown in Figure 9.

[0046] In addition, the first gear portion 67c formed on the swing support shaft 67a also rotates clockwise, so that the second gear portion 78d meshing with the first gear portion 67c also rotates counterclockwise. As a result, the link member 78 rotates counterclockwise about the rotation shaft 78b, and the movable guide 69 engaged with the link member 78 moves downward and is positioned at the release position shown in FIG.

[0047] On the other hand, when the drive input gear 76 is rotated a predetermined angle in the counterclockwise direction (reverse direction) from the state shown in FIG. 9, the folding blade 67 together with the oscillating support shaft 67a also rotates a predetermined angle in the counterclockwise direction (reverse direction) of FIG. 8, and is positioned in the retracted position shown in FIG. 8.

[0048] In addition, the first gear portion 67c formed on the swing support shaft 67a also rotates counterclockwise, so that the second gear portion 78d meshing with the first gear portion 67c also rotates clockwise. As a result, the link member 78 rotates clockwise about the rotation shaft 78b, and the movable guide 69 engaged with the link member 78 moves upward and is positioned at the cover position shown in FIG.

[0049] According to the configuration of this embodiment, the swing support shaft 67a of the folding blade 67 is located on the same side of the sheet S to be folded as the pair of folding rollers 64. Therefore, the movement trajectory of the blade portion 67b when pushing the sheet S into the first nip portion N1 can be made substantially perpendicular to the sheet S, and the sheet S can be pushed into the first nip portion N1 with high accuracy.

[0050] Furthermore, when the folding blade 67 is disposed at the retracted position, a retract path 73 is formed between the pivot shaft 67a and the blade portion 67b of the folding blade 67. This ensures that the retract path 73 for the paper S can be secured even if the pivot shaft 67a and the blade portion 67b of the folding blade 67 are disposed on opposite sides of the paper S, increasing the degree of freedom in the position where the folding blade 67 is disposed.

[0051] In this embodiment, a movable guide 69 is provided that can move between a cover position that covers the outer circumferential surface of the second roller 63b of the folding roller pair 64 and a release position that exposes the outer circumferential surface of the second roller 63b. As a result, when the sheet S is caused to enter the retreat path 73 before folding processing, by placing the movable guide 69 in the cover position, it is possible to avoid contact with the second roller 63b of the folding roller pair 64 that rotates in the opposite direction to the conveying direction, thereby preventing jamming or folding of the edge of the sheet S. Then, by placing the movable guide 69 in the release position when folding processing is performed, it is possible to smoothly push the sheet S into the first nip portion N1 by the folding blade 67.

[0052] Furthermore, by driving the folding blade 67 and the movable guide 69 using a drive mechanism 90 including one drive motor 91, the movable guide 69 moves to the release position in conjunction with the movement of the folding blade 67 to the folding position, and the movable guide 69 moves to the cover position in conjunction with the movement of the folding blade 67 to the retracted position. This eliminates the need to synchronize the movement timing of the folding blade 67 and the movable guide 69, and allows for a simplification of the control mechanism by the post-processing control unit 101. Furthermore, the number of motors can be reduced, which contributes to cost reduction.

[0053] Furthermore, the first roller 63a constitutes a folding roller pair 64 together with the second roller 63b, and constitutes a first conveying roller pair 65 together with the third roller 63c, so that the first roller 63a serves both as the folding roller pair 64 and the first conveying roller pair 65. This makes it possible to reduce the number of rollers and the arrangement space.

[0054] In addition, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, an example is shown in which the first paper folding unit 60 includes a folding roller pair 64 consisting of three rollers, the first roller 63a to the third roller 63c, and a first transport roller pair 65, but the present invention is not limited to this, and for example, as shown in Fig. 10, the first paper folding unit 60 may be configured to include only the folding roller pair 64 consisting of the first roller 63a and the second roller 63b. In this case, the paper S is transported from a transport roller pair (not shown) upstream of the first paper folding unit 60.

[0055] In addition, in the above embodiment, the first gear portion 67c is formed on the oscillating support shaft 67a of the folding blade 67, and the second gear portion 78d is formed on the rotating shaft 78b of the link member 78, thereby directly connecting the folding blade 67 and the link member 78, but the folding blade 67 and the link member 78 may also be connected by interposing one or more gears between them.

[0056] In addition, in the above embodiment, a multifunction peripheral as shown in FIG. 2 is exemplified as an example of the image forming device 10, but the paper post-processing device 30 of the present invention can also be connected to image forming devices other than digital multifunction peripherals, such as laser printers, inkjet printers, facsimile machines, etc. [Explanation of symbols]

[0057] 10 Image forming device 30 Paper post-processing device (sheet post-processing device) 60 First paper folding unit (sheet folding device) 61 Sheet access route 63a 1st Roller 63b 2nd Roller 63c 3rd Roller 63d 4th Roller 64 Folding roller pair 65 First conveyor roller pair 66 Second conveyor roller pair 67 Folding Blade 67a Swing fulcrum 67b Blade section 67c Arm section 67d First gear section 68 Fixed guide 69 Movable guide 70 First pressure welding mechanism 71 Second pressure welding mechanism 72 Switching Guide 73 Turnout 76 Drive input gear 78 Link member 78a Base 78b Rotation axis 78c Engagement boss 78d 2nd gear section 80 Second paper folding unit 90 Drive Mechanism 91 Drive motor (drive source) S Paper (sheet) N1 First nip section N2 1st nip section F, F1, F2 folds

Claims

1. a pair of folding rollers that pass a sheet through a first nip portion, fold the sheet in half, and transport the sheet in a first direction; a folding blade disposed opposite the pair of folding rollers and pressing a folded portion of the sheet into the first nip portion in the first direction to perform folding processing; a sheet guide disposed on a sheet transport path extending along a second direction intersecting the first direction on an upstream side of the pair of folding rollers with respect to the first direction; In a sheet folding device comprising: The folding blade is a pivot shaft disposed on the same side as the pair of folding rollers with respect to the sheet conveying path in the first direction and parallel to an axis of the pair of folding rollers; a blade portion that is swung about the swing support shaft and selectively disposed at a folding position where the folded portion of the sheet is pushed into the first nip portion in the first direction and at a retreated position where the blade portion is retreated from the folding position to an opposite side of the pair of folding rollers across the sheet transport path; a pair of arms connecting both axial ends of the blade portion to the swing support shaft; having the sheet guide is capable of passing between the pair of arm portions when the blade portion moves between the folding position and the retracted position, the blade portion forms a retreat path between the blade portion and the sheet guide, through which the sheet can pass, when the blade portion is disposed at the retreat position; the pair of folding rollers includes a first roller disposed on the upstream side in the second direction and a second roller disposed on the downstream side in the second direction and pressed against the first roller, the sheet guide is a movable guide that is reciprocally movable between a cover position that covers an area of ​​an outer circumferential surface of the second roller that faces the sheet transport path and a release position that exposes the outer circumferential surface of the second roller; a drive mechanism for reciprocating the blade portion between the folding position and the release position and for reciprocating the movable guide between the cover position and the release position, The drive mechanism is A drive motor; a drive input gear fixed to the swing support shaft and configured to input a drive force from the drive motor to the swing support shaft; a first gear portion formed in an arc shape along a portion of the circumferential direction of an outer circumferential surface of the swing support shaft; a link member having a second gear portion that meshes with the first gear portion and with which the movable guide is engaged; having By rotating the drive input gear in a forward direction by a predetermined angle, the blade portion rotates together with the swing support shaft in the forward direction by the predetermined angle and is positioned at the folding position, and the movable guide that engages with the link member is positioned at the release position, A sheet folding device characterized in that, by rotating the drive input gear in the reverse direction a predetermined angle, the blade portion rotates in the reverse direction together with the oscillating support shaft a predetermined angle and is positioned at the retracted position, and the movable guide engaging with the link member is positioned at the cover position.

2. A sheet folding device as described in Claim 1, characterized in that the movable guide is arranged between the oscillating support shaft and the blade portion, and the escape path is formed by the movable guide and the side of the blade portion facing the oscillating support shaft.

3. A conveying roller pair is provided which is composed of the first roller and a third roller pressed against the first roller and conveys the sheet in the second direction; 3. The sheet folding device according to claim 1, wherein the pair of transport rollers is a pair of folding rollers used when folding the sheet in three.

4. A sheet post-processing device equipped with a sheet folding device described in any one of claims 1 to 3.

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