Sheet folding device and sheet post-processing device equipped therewith, and image forming system

Abstract

To provide a sheet folding device capable of preventing a position in a sheet-conveying direction of sheets stacked on a sheet-stacking unit from being displaced; and to provide a sheet post-processing device comprising the same, and an image forming system.SOLUTION: A sheet folding device comprises a sheet-stacking unit, a fold-processing unit, and a discharge roller. The fold-processing unit comprising a folding roller pair comprises a sheet adjusting part and a seat moving part. A sheet stacking tray comprises an upstream side stacking part and a downstream side stacking part. The sheet adjusting part comprises an upstream side adjusting part and a downstream side adjusting part. The downstream side adjusting part comprises a side plate, a fixed guide plate, and a movable guide plate supported to the side plate between a retreat position and a regulation position in a swingable manner.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sheet folding apparatus, a sheet post-processing apparatus including the same, and an image forming system. [Background Art]

[0002] Conventionally, a sheet post-processing apparatus has been used that stacks a plurality of sheets (printing paper, envelopes, OHP sheets, etc.) on which images have been formed by an image forming apparatus (a copier, a printer, etc.) into a bundle, and performs predetermined post-processing on the bundle. The predetermined post-processing includes binding processing (processing of binding a sheet bundle with staples), folding processing (processing of folding a sheet into two or three folds), and the like.

[0003] As such a sheet post-processing apparatus, Patent Document 1 discloses an apparatus including a sheet folding apparatus for performing folding processing. The sheet folding apparatus of Patent Document 1 includes a sheet stacking unit, a sheet conveying path, a folding processing unit, and a sheet aligning unit.

[0004] Sheets are stacked on the sheet stacking unit. Sheets stacked on the sheet stacking unit pass through the sheet conveying path. The folding processing unit performs a predetermined folding process on the sheets stacked on the sheet stacking unit.

[0005] The sheet aligning unit abuts against sheets stacked on the sheet stacking unit in the sheet conveying direction and the sheet width direction to position the sheets. The sheet aligning unit includes a flat portion (fixed guide plate). The flat portion is parallel to and opposed to the sheet stacking surface (the surface on which sheets are stacked) of the sheet stacking unit. Sheets are stacked between the flat portion and the sheet stacking surface. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Laid-Open No. 2007-145569 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, the gap between the sheet loading surface and the flat section is relatively large to allow for smooth loading of sheets. Therefore, if a sheet loaded on the sheet loading surface is curled and bent, even if the sheet and the flat section come into contact, the curl may not be corrected, or the correction may be insufficient. When a sheet is curled, the leading edge of the sheet rolls back towards the trailing edge, which may cause misalignment in the sheet alignment unit's positioning in the sheet transport direction. This may result in misalignment in the folding process applied to the sheet, or malfunctions in the folding unit's operation.

[0008] Therefore, the present invention aims to provide a sheet folding device capable of suppressing misalignment of the sheet in the sheet transport direction when sheets are loaded onto a sheet loading unit, a sheet post-processing device equipped therewith, and an image forming system. [Means for solving the problem]

[0009] To achieve the above objective, the first configuration of the present invention is a sheet folding device comprising a sheet loading unit, a folding unit, and a discharge roller. The sheet loading unit is used to load sheets that have passed through a sheet transport path. The folding unit has a pair of folding rollers and performs a predetermined folding process by nipping the sheets loaded in the sheet loading unit with the folding rollers. The discharge roller is positioned downstream of the folding unit with respect to the sheet transport direction and discharges the folded sheets downstream in the sheet transport direction. The sheet loading unit comprises a sheet loading tray on which sheets are loaded, a sheet alignment unit supported on the sheet loading tray so as to be reciprocally movable in the sheet width direction perpendicular to the sheet transport direction and contacting the sheets loaded in the sheet loading unit to position them in the sheet width direction, and a sheet moving unit supported on the sheet loading tray so as to be reciprocally movable in the sheet transport direction and moves the sheets loaded in the sheet loading unit to a predetermined position in the sheet transport direction. The sheet loading tray is positioned upstream in the sheet transport direction with a gap formed between it and the nip portion of the folding roller pair, and includes an upstream loading section including an upstream loading surface, and is positioned downstream in the sheet transport direction with the gap in between, and includes a downstream loading surface. The sheet alignment section includes an upstream alignment section that contacts the portion of the sheet loaded on the upstream loading section to position it in the sheet width direction, and a downstream alignment section that contacts the portion of the sheet loaded on the downstream loading section to position it in the sheet width direction. The downstream alignment section includes a side plate that is upright with respect to the downstream loading surface and contacts the side surface of the sheet, a fixed guide plate provided on the upstream side of the side plate in the sheet transport direction, facing the downstream loading surface at a predetermined height, and regulating the upper surface of the sheet, and a movable guide plate provided downstream of the fixed guide plate in the sheet transport direction, with a pivot point located above the fixed guide plate in the portion upstream of the center in the sheet transport direction, and swingable between a retracted position where the downstream end in the sheet transport direction is above the fixed guide plate and a regulating position where the upper surface of the sheet is regulated at a position below the fixed guide. [Effects of the Invention]

[0010] According to the first configuration of the present invention, when the movable guide plate is in the restricted position, the distance between the sheet and the movable guide plate becomes smaller than the distance between the sheet and the fixed guide plate. As a result, the sheet transported to the sheet loading unit is positioned closer to the movable guide plate than to the fixed guide plate. Consequently, even if the leading edge of the transported sheet is curled, it becomes possible to correct the curl by contact with the movable guide plate. Furthermore, it becomes possible to correct the curl more strongly than by contact with the fixed guide plate. Therefore, it is possible to provide a sheet folding device that can suppress misalignment of the sheet's position in the sheet transport direction when the sheet is loaded onto the sheet loading unit. [Brief explanation of the drawing]

[0011] [Figure 1] Schematic diagram showing the image forming apparatus 10 and sheet post-processing device 30 that constitute the image forming system 1. [Figure 2] Schematic diagram showing the internal configuration of the image forming apparatus 10 [Figure 3] Schematic diagram showing the internal configuration of the sheet post-processing device 30. [Figure 4] Cross-sectional view showing the internal configuration of the sheet post-processing device 30 around the sheet folding device 60. [Figure 5] A cross-sectional view showing an enlarged view of the area around the first folding device 70. [Figure 6] A cross-sectional view showing an enlarged view of the first folding device 70 with the sheet S loaded inside. [Figure 7] A cross-sectional view showing an enlarged view of the area around the first folding device 70, with the sheet S being discharged by the discharge roller pair 86. [Figure 8] Side view of the sheet post-processing device 30 [Figure 9] A perspective view showing the sheet post-processing device 30 with the tray unit 110 positioned in the second position. [Figure 10] Perspective view showing the upstream loading section 63a [Figure 11] Perspective view showing the downstream loading section 63b [Figure 12] Perspective view showing the downstream width-adjusting member 653b [Figure 13] A cross-sectional view showing a cross-section orthogonal to the sheet width direction of the second regulating member 28 positioned at the regulating position P1 [Figure 14] A cross-sectional view showing a cross-section orthogonal to the sheet width direction of the second regulating member 28 positioned at the retracted position P2 [Figure 15] A cross-sectional view showing a cross-section orthogonal to the sheet width direction of the second regulating member 28 in a state where the sheet S stacked on the downstream stacking surface 25 is in contact with the lifting portion 59 MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an image forming system 1 constituted by a sheet post-processing apparatus 30 and an image forming apparatus 10 connected to the sheet post-processing apparatus 30 will be described. For convenience of description, a single sheet and a bundle of a plurality of sheets are collectively referred to simply as "sheet S". Further, the conveying direction of the sheet S is referred to as "sheet conveying direction", the width direction of the sheet S (the direction orthogonal to the sheet conveying direction) is referred to as "sheet width direction", and the stacking direction of the sheet S onto the sheet stacking unit 63 (the direction orthogonal to both the sheet conveying direction and the sheet width direction) is referred to as "sheet stacking direction".

[0013] FIG. 1 is a schematic diagram showing the image forming apparatus 10 and the sheet post-processing apparatus 30 that constitute the image forming system 1. As shown in FIG. 1, the image forming apparatus 10 is used connected to the sheet post-processing apparatus 30. The image forming apparatus 10 prints an image on the sheet S 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 disposed at an upper portion of the image forming apparatus 10.

[0014] FIG. 2 is a schematic diagram showing the internal configuration of an image forming apparatus 10. As shown in FIG. 2, the image forming apparatus 10 includes a paper feeding unit 15 that feeds a sheet S, an image forming unit 18 that forms a toner image on the sheet S, a fixing unit 19 for fixing the toner image on the sheet S, discharge roller pairs 23 and 24 that convey the fixed sheet and discharge it to a paper discharge unit 21 and a sheet post-processing apparatus 30 respectively, and a main body control unit 100. The main body control unit 100 controls the operation of the image forming apparatus 10, is configured to be able to communicate with a post-processing control unit 101 described later of the sheet post-processing apparatus 30, and controls the post-processing control unit 101.

[0015] FIG. 3 is a schematic diagram showing the internal configuration of a sheet post-processing apparatus 30. The sheet post-processing apparatus 30 performs post-processing such as punching hole forming processing, binding processing, and folding processing on the sheet S conveyed from the image forming apparatus 10. As shown in FIG. 3, the sheet post-processing apparatus 30 includes a sheet carry-in port 36, a main discharge tray 38, a sub discharge tray 40, a lower discharge tray 121, a sheet conveying path 32, a retraction drum 41, a registration roller pair 46, a post-processing mechanism 20, a post-processing control unit 101, and a tray unit 110.

[0016] The sheet carry-in port 36 receives the sheet S discharged from a discharge unit 7 (see FIG. 2) of the image forming apparatus 10. The main discharge tray 38, the sub discharge tray 40, and the lower discharge tray 121 are plate-shaped bodies on which the sheet S can be stacked on an upper surface, and serve as the final discharge destinations of the sheet S carried into the sheet post-processing apparatus 30 from the sheet carry-in port 36.

[0017] The main discharge tray 38 is supported on a side surface 161a (the side surface opposite to the image forming apparatus 10) of the main body of the sheet post-processing apparatus 30 so as to be able to move up and down. The main discharge tray 38 moves up and down in accordance with the stacking amount of the stacked sheets S. A main discharge port 37 is formed on the one side surface 161a. The main discharge port 37 is located further upward than the main discharge tray 38 in the state of being positioned at the highest position.

[0018] The sub-discharge tray 40 is fixed to the upper part of the sheet post-processing device 30, above the main discharge tray 38. A sub-discharge port 39 is formed on the upper part of the body of the sheet post-processing device 30, above the upstream end of the sub-discharge tray 40 with respect to the sheet transport direction.

[0019] The lower discharge tray 121 is located at the bottom of the sheet post-processing device 30 and is supported below the main discharge tray 38. A lower discharge port 85 is formed on one side 161a above the lower discharge tray 121.

[0020] The sheet transport path 32 is a passage formed inside the sheet post-processing device 30 for transporting sheets. Sheets S brought into the sheet post-processing device 30 from the sheet entrance 36 are transported through the sheet transport path 32 to a predetermined location in the sheet post-processing device 30. The sheet transport path 32 consists of a first transport path 42, a second transport path 43, a third transport path 44, and a fourth transport path 45.

[0021] The first conveying path 42 extends from the sheet inlet 36 to the main discharge port 37. A pair of main discharge rollers 47 is provided at the downstream end of the first conveying path 42 in the sheet conveying direction. The pair of main discharge rollers 47 is a pair of roller bodies that can rotate in both forward and reverse directions and are provided so as to be able to press against or separate from each other. The pair of main discharge rollers 47 can convey the sheet S to the main discharge tray 38 along the sheet conveying direction, or toward the first staple unit 35, which will be described later, in the opposite direction to the sheet conveying direction.

[0022] When transporting the sheet S to the main discharge tray 38, the main discharge roller pair 47 is pressed together and rotated in the forward direction, and the sheet S that enters between the rollers is sent to the main discharge tray 38 through the main discharge port 37. Conversely, when transporting the sheet S to the first staple unit 35, the main discharge roller pair 47 is separated and the sheet S enters between the rollers, and then the main discharge roller pair 47 is pressed together and rotated in the reverse direction to send the sheet S to the first staple unit 35.

[0023] The second transport path 43 branches upward from the first transport path 42 and extends toward the sub-discharge port 39. The upstream end of the second transport path 43 is connected to the middle of the first transport path 42, and the downstream end is connected to the sub-discharge port 39. A first branching member 3 is provided at the connection point between the first transport path 42 and the second transport path 43. The first branching member 3 distributes the sheets S brought in from the sheet loading port 36 to the downstream side of the first transport path 42 or to the second transport path 43.

[0024] A pair of sub-discharge rollers 48 is provided at the downstream end of the second transport path 43. The pair of sub-discharge rollers 48 sends the sheet S that has been transported in the second transport path 43 to the sub-discharge tray 40 through the sub-discharge port 39.

[0025] The third transport path 44 branches off downward from the first transport path 42. The upstream end of the third transport path 44 is connected via the fourth transport path 45, which will be described later, to a location downstream of the branching point of the first transport path 42 with the second transport path 43. The downstream end of the third transport path 44 extends downward and is connected to the sheet folding device 60, which will be described later.

[0026] The fourth transport path 45 is a circular transport path that branches off from the first transport path 42 and rejoins the first transport path 42. Specifically, the fourth transport path 45 branches off from the first transport path 42 downstream of the branching point between the first transport path 42 and the third transport path 44, and rejoins the first transport path 42 further downstream. The upstream end of the third transport path 44 is connected to the middle of the fourth transport path 45.

[0027] A second branching member 4 is positioned at the connection point between the first transport path 42 and the fourth transport path 45. The second branching member 4 distributes the sheets S distributed downstream of the first transport path 42 by the first branching member 3 to the third transport path 44, either further downstream of the first transport path 42 or via the fourth transport path 45.

[0028] The retractable drum 41 is a rotatable roller body provided inside the annular fourth transport path 45. The outer surface of the retractable drum 41 faces the inner surface of the fourth transport path 45, defining the fourth transport path 45.

[0029] The retraction drum 41 rotates with the sheets S distributed in the direction of the third transport path 44 by the second branching member 4 in contact with its outer surface, temporarily retracting the sheets S to the fourth transport path 45, and then feeding them back to the first transport path 42. For example, when stapling multiple sheet bundles in succession, while stapling is being performed on the previous sheet bundle, the retraction drum 41 retracts the first sheet S, which will form the next sheet bundle, to the fourth transport path 45. Then, it is transported back to the first transport path 42 from the fourth transport path 45 so that it is transported to the first staple unit 35 while overlapping with the second sheet S.

[0030] A pair of resist rollers 46 is positioned upstream of the first distribution unit 3 in the first transport path 42. The pair of resist rollers 46 sends the sheet S, which has been fed in from the sheet inlet 36, downstream.

[0031] The post-processing mechanism 20 includes a punch hole forming device 33, a first staple unit 35, a sheet folding device 60, and a second staple unit 68.

[0032] The punch hole forming device 33 is positioned between the sheet input 36 and the resist roller pair 46 in the sheet conveying direction. The punch hole forming device 33 faces the sheet S being conveyed in the first conveying path 42 in the vertical direction. The punch hole forming device 33 performs punching on the sheet S being conveyed in the first conveying path 42 at predetermined timings.

[0033] The post-processing control unit 101 is connected to each mechanism of the sheet post-processing device 30 (punch hole forming device 33, first staple unit 35, sheet folding device 60, etc.) and controls predetermined post-processing and conveyance of the sheet S.

[0034] The first stapling unit 35 is located downstream of the connection point between the first transport path 42 and the third transport path 44, and upstream of the main discharge roller pair 47, and is positioned on the lower side of the first transport path 42. The first stapling unit 35 performs stacking and stapling on multiple sheets S that have been transported by the operation of the main discharge roller pair 47 described above. Stacking is the process of stacking multiple sheets S to form a sheet bundle. Stapling is the process of stapling the stacked sheet bundle with staples.

[0035] Figure 4 is a cross-sectional view showing the internal configuration of the sheet post-processing device 30 around the sheet folding device 60. As shown in Figure 4, the sheet folding device 60 is located at the bottom of the sheet post-processing device 30, downstream of the third transport path 44. The sheet folding device 60 performs a folding process on the sheet S, for example, by folding it in half or in thirds, when the user selects the folding process.

[0036] The sheet folding device 60 includes a sheet loading path 61, a sheet loading unit 63, a matching member 65, a sheet moving section 64, a first folding device 70 (folding processing unit), a waiting path 81, a second folding device 90 (folding processing unit), a transport destination switching member 83, and a lower discharge tray (discharge tray) 121.

[0037] The sheet loading path 61 is a loading path for loading the sheet S, which has been transported along the third transport path 44, into the sheet folding device 60. The sheet loading path 61 extends downward from the downstream end of the third transport path 44. At the downstream end of the sheet loading path 61, there is a pair of loading rollers 612 that feeds the sheet S into the sheet folding device 60.

[0038] The sheet loading unit 63 is used to load the sheets S that have been brought in from the sheet loading path 61. The sheet loading unit 63 consists of an upstream loading section 63a and a downstream loading section 63b.

[0039] The upstream loading section 63a and the downstream loading section 63b are plate-shaped members. The downstream loading section 63b is arranged in a straight line with a gap between it and the upstream loading section 63a, downstream of the upstream loading section 63a with respect to the sheet transport direction. An upstream loading surface 24 (see Figure 10) is formed on the upper surface of the upstream loading section 63a. A downstream loading surface 25 (see Figure 11) is formed on the upper surface of the downstream loading section 63b. The upstream loading surface 24 and the downstream loading surface 25 are arranged on the same plane along the sheet transport direction and constitute the sheet loading surface 62. The sheet loading surface 62 slopes downward from the upstream side to the downstream side in the sheet transport direction.

[0040] The upstream loading surface 24 faces the second staple unit 68. The second staple unit 68 is capable of stapling the sheets S loaded on the sheet loading surface 62.

[0041] The alignment member 65 aligns the edges of the sheets S in the width direction with those of the sheets S placed on the sheet stacking unit 63. The sheet moving unit 64 moves the sheets S placed on the sheet stacking unit 63 to a predetermined position in the sheet transport direction. Alignment of the sheets S by the alignment member 65 is performed each time a sheet S is stacked on the sheet stacking unit 63. Movement of the sheets S by the sheet moving unit 64 is performed after alignment of the sheets S by the alignment member 65. When a predetermined number of sheets S are reached, if binding is to be performed, they are bound by the second staple unit 68, and then transported directly to the first folding device 70 if binding is not to be performed.

[0042] The first folding device 70 performs a first folding process to fold the sheet S in half. The first folding device 70 includes an extrusion mechanism 71 and a first folding roller pair 75. The extrusion mechanism 71 extrudes the sheet S. The first folding roller pair 75 performs a folding process on the sheet S extruded by the extrusion mechanism 71.

[0043] The extrusion mechanism 71 comprises a folding blade 72 and an extrusion drive unit 73. The folding blade 72 is a metal plate-shaped body. The folding blade 72 is positioned between the upstream loading section 63a and the downstream loading section 63b with respect to the sheet conveying direction. The folding blade 72 is supported so as to be able to reciprocate in the sheet loading direction.

[0044] The extrusion drive unit 73 is composed of a motor capable of outputting driving force and a plurality of gears (not shown), and is connected to the folding blade 72. The extrusion drive unit 73 outputs rotational driving force to the folding blade 72, causing the folding blade 72 to move back and forth.

[0045] Figure 5 is a cross-sectional view showing an enlarged view of the periphery of the first folding device 70. As shown in Figures 4 and 5, the first folding roller pair 75 consists of a first roller 76 and a second roller 77. The first roller 76 and the second roller 77 are pressed against each other, forming a first nip portion N1 between them. The first roller 76 and the second roller 77 are rotationally driven by a drive unit (neither of which is shown) via a power transmission mechanism.

[0046] The sheet S, pushed out by the folding blade 72, enters the first nip section N1. Thereupon, the sheet S is sandwiched between the first roller 76 and the second roller 77 in the first nip section N1 and passes through the first nip section N1, forming the first fold in the sheet S.

[0047] Downstream of the first nip section N1, a first discharge conveying path 88 is provided, which is connected to the lower discharge port 85. At the downstream end of the first discharge conveying path 88, a pair of discharge rollers 86 is provided.

[0048] Figure 6 is an enlarged cross-sectional view showing the first folding device 70 with the sheet S loaded into it. The waiting path 81 branches off from the first discharge transport path 88. As shown in Figure 6, the waiting path 81 allows the sheet S that has undergone the first folding process by the first folding device 70 to enter and bend while being stored. The waiting path 81 is formed to correspond to the thickness of the maximum number of sheets S that can be folded by the sheet folding device 60. For example, if folding can be performed on 1 to 5 sheets S, the waiting path 81 has a gap that allows a sheet S with the thickness of 10 sheets (the thickness of 5 sheets when folded) to enter.

[0049] A stopper 81a is provided at the downstream end of the waiting path 81. The first fold of the sheet S entering (taking refuge in) the waiting path 81 comes into contact with the stopper 81a.

[0050] The second folding device 90 performs a second folding process on the sheet S that is in contact with the stopper 81a. The second folding device 90 has a second folding roller pair 91. The second folding roller pair 91 consists of the first roller 76 and the third roller 92 described above.

[0051] The first roller 76 and the third roller 92 are pressed against each other, forming a second nip portion N2 between them. The third roller 92 rotates in accordance with the first roller 76. As shown in Figure 6, when the leading edge (first fold) of the sheet S, which has undergone the first folding process, is in contact with the stopper 81a, and the sheet transport continues by the first folding roller pair 75, a flex portion S1 is created in the sheet S. This flex portion S1, as it passes between the second roller 77 and the third roller 92 in the second nip portion N2, forms a second fold in the sheet S.

[0052] The transport destination switching member 83 is provided at the branching point between the standby path 81 and the first discharge transport path 88. The transport destination switching member 83 guides the sheet S, which has undergone the first folding process, to either the first discharge transport path 88 or the standby path 81. When transporting the sheet S, which has undergone the first folding process, to the lower discharge port 85 without performing a second folding process, the transport destination switching member 83 guides the sheet S directly from the first nip section N1 to the first discharge transport path 88 (see Figure 7).

[0053] Returning to Figure 5, a second discharge conveying path 89 is provided downstream of the second nip section N2, which merges with the first discharge conveying path 88. The second discharge conveying path 89 is a conveying path that transports the sheet S, which has undergone the second folding process, to the lower discharge port 85 via the first discharge conveying path 88.

[0054] Figure 8 is a side view of the sheet post-processing device 30. Figure 9 is a perspective view showing the sheet post-processing device 30 with the tray unit 110 positioned in the second position. As shown in Figures 8 and 9, the tray unit 110 is composed of the lower discharge tray 121, the tray body 49, and the pivot shaft 111. The lower discharge tray 121 is fixed to the upper part of the tray body 49.

[0055] The pivot shaft 111 is a shaft parallel to the sheet width direction. The pivot shaft 111 is provided at the upstream end of the tray body 49 in the sheet discharge direction. The pivot shaft 111 is supported by the main body portion (frame etc. that constitute the housing) of the sheet post-processing device 30. The tray body 49 is pivotable along the circumferential direction of the pivot shaft 111 between a first position (position in Figure 4) in which sheets S discharged from the lower discharge port 85 can be loaded onto the lower discharge tray 121, and a second position (positions in Figures 8 and 9) in which the sheet loading unit 63 inside the main body of the sheet post-processing device 30 is exposed from one side surface 161a.

[0056] When the tray unit 110 is positioned in the second position, the area around the lower end of the sheet loading unit 63 is exposed. With the tray body 49 positioned in the second position, it becomes possible to remove jammed sheets S from the sheet loading unit 63 or the first folding device 70 (see Figure 4) via the area below the tray unit 110.

[0057] Next, with reference to Figures 4 to 7, the folding process (operation) of the sheet S by the sheet folding device 60 will be described.

[0058] First, let's explain the folding process. The folding process is performed when the user selects the folding mode using the operation panel 12 (see Figure 2) of the image forming apparatus 10. The transport destination switching member 83 rotates to the position shown by the solid line in Figure 5, directing the transport destination of the sheet S, which has undergone the first folding process by the first folding device 70, towards the first discharge transport path 88.

[0059] The sheet S, brought in from the sheet loading path 61, is placed on the upstream loading section 63a and the downstream loading section 63b. The alignment member 65 then aligns the edges of the sheet S in the sheet width direction. The sheet moving section 64 then positions (moves) the sheet S so that the folding position of the sheet S (the center in the sheet transport direction) and the tip of the folding blade 72 overlap with the sheet transport direction.

[0060] Next, the folding blade 72 is extended in the direction opposite to the sheet loading direction. As a result, the tip of the folding blade 72 contacts the back surface of the sheet S, and the extension of the folding blade 72 pushes the sheet S upward (in a direction perpendicular to the sheet S). The sheet S pushed out by the folding blade 72 enters the first nip portion N1 of the first folding roller pair 75 in a bent state. A first fold is formed in the sheet S after it has passed through the first nip portion N1.

[0061] As shown in Figure 7, the sheet S with the first fold formed is discharged through the first discharge conveying path 88 to the lower discharge port 85 and then to the lower discharge tray 121. The extrusion mechanism 71 returns the folding blade 72 to its original standby position. The folding process is then carried out continuously in the same manner.

[0062] Next, the tri-fold process will be explained. The tri-fold process is performed when the user selects the tri-fold mode using the operation panel 12 (see Figure 2) of the image forming apparatus 10. The process until the first folding process is performed on the sheet S by the first folding device 70 is the same as the bi-fold process described above, except that the folding position of the sheet S is set to a position approximately 1 / 3 of the sheet length from the leading edge of the sheet S, so the explanation will be omitted.

[0063] Returning to Figure 5, in the tri-fold mode, the transport destination switching member 83 rotates to the position indicated by the dashed line in Figure 5, directing the transport destination of the sheet S, which has undergone the first folding process by the first folding device 70, toward the waiting path 81. Therefore, the sheet S, which has undergone the first folding process, is transported toward the waiting path 81. When the sheet S enters the waiting path 81, the first fold (leading edge) of the sheet S abuts against the stopper 81a.

[0064] Even after the first fold of the sheet S hits the stopper 81a, the first folding roller pair 75 continues to rotate. As a result, as shown in Figure 6, the sheet S bends so that it becomes convex towards the second nip portion N2 of the second folding roller pair 91, while contacting the inner surface of the curved waiting path 81 and the transport destination switching member 83, etc.

[0065] The flexed portion S1 in the sheet S (located approximately 1 / 3 of the sheet length from the rear end of the sheet S) enters the second nip portion N2 of the second folding roller pair 91. A second fold is formed in the sheet S after it has passed through the second nip portion N2. The sheet S with the second fold is conveyed along the second discharge conveying path 89 while wrapping around the circumferential surface of the third roller 92, and is discharged from the lower discharge port 85 to the lower discharge tray 121 by the discharge roller pair 86.

[0066] Next, the configuration of the alignment member 65 and the sheet moving part 64 will be described in detail. Returning to Figure 4, the alignment member 65 comprises an upstream width-adjusting member 653a (upstream alignment part) and a downstream width-adjusting member 653b (downstream alignment part). The sheet moving part 64 comprises an upper moving member 651 (first claw part) and a lower moving member 652 (second claw part).

[0067] The upper moving member 651 is supported on the upstream loading section 63a so as to be able to reciprocate in the sheet transport direction. Below the upstream loading section 63a, an upstream drive pulley 654a and an upstream driven pulley 654b are provided. An upstream belt 655 is stretched between the upstream drive pulley 654a and the upstream driven pulley 654b. The upper moving member 651 is attached to the upstream belt 655. The upstream drive pulley 654a is connected to a drive unit such as a motor (not shown) and rotates due to the rotational driving force of this drive unit. As the upstream drive pulley 654a rotates, the upstream belt 655 rotates in response, causing the upper moving member 651 to reciprocate.

[0068] The lower moving member 652 is supported on the downstream loading section 63b so as to be able to reciprocate in the sheet transport direction. Below the downstream loading section 63b, a downstream drive pulley 656a and a downstream driven pulley 656b are provided. A downstream belt 657 is stretched between the downstream drive pulley 656a and the downstream driven pulley 656b. The lower moving member 652 is attached to the downstream belt 657. The downstream drive pulley 656a is connected to a drive unit such as a motor (not shown) and rotates due to the rotational driving force of this drive unit. As the downstream drive pulley 656a rotates, the downstream belt 657 rotates in response, causing the lower moving member 652 to reciprocate.

[0069] The lower moving member 652 contacts the leading edge (downstream end in the sheet transport direction) of the sheet S loaded on the sheet loading surface 62, and receives the leading edge of the sheet S. The upper moving member 651 contacts the rear end (upstream end in the sheet transport direction) of the sheet S that has been received by the lower moving member 652. In this way, the upper moving member 651 and the lower moving member 652 contact both edges of the sheet S loaded on the sheet loading unit 63 in the sheet transport direction, aligning the leading edge and rear end of the sheet S at predetermined positions.

[0070] The upstream width-adjusting member 653a and the downstream width-adjusting member 653b are designed to move in the sheet width direction to match the size of the sheet S (length in the sheet width direction). The upstream width-adjusting member 653a and the downstream width-adjusting member 653b contact both edges of the sheet S in the sheet width direction, thereby adjusting the width of the sheet S and correcting its skewness.

[0071] Figure 10 is a perspective view showing the upstream loading section 63a. As shown in Figure 10, the upstream width-adjusting member 653a consists of a pair of first restricting members 26 and 27. The first restricting members 26 and 27 are aligned in the sheet width direction. The first restricting members 26 and 27 are positioned to overlap with the upstream loading section 63a with respect to the sheet transport direction. The first restricting members 26 and 27 are supported by the upstream loading section 63a by a rack and pinion mechanism (not shown) so as to be able to reciprocate in the sheet width direction.

[0072] Since the first regulating members 26 and 27 are symmetrical in the sheet width direction and have basically the same configuration, only the first regulating member 26 will be described below, and the first regulating member 27 will be given the same reference numeral and its description will be omitted.

[0073] The first regulating member 26 comprises an upstream bottom surface 50, an upstream side wall portion 51, and an upstream flat portion 52. The upstream bottom surface 50 is a surface parallel to the upstream loading surface 24. The upstream bottom surface 50 is located below the upstream loading surface 24. That is, when the sheet S is loaded on the sheet loading surface 62, the upstream bottom surface 50 is located further from the sheet S than the upstream loading surface 24.

[0074] The upstream side wall portion 51 is a plate-like portion perpendicular to the upstream bottom surface 50. The upstream side wall portion 51 is connected to the outer edge (outside in the sheet width direction) of the upstream bottom surface 50 with respect to the sheet width direction.

[0075] The upstream flat portion 52 is a plate-like portion parallel to the upstream bottom surface 50. The upstream flat portion 52 extends from the edge of the upstream side wall portion 51 in the direction opposite to the sheet loading direction toward the inside in the sheet width direction (towards the center of the upstream loading surface 24 with respect to the sheet width direction). The upstream flat portion 52 faces the upstream bottom surface 50 with respect to the sheet loading direction.

[0076] Figure 11 is a perspective view showing the downstream loading section 63b. Figure 12 is a perspective view showing the downstream width-adjusting member 653b. As shown in Figures 11 and 12, the downstream width-adjusting member 653b is composed of second restricting members 28 and 29. The second restricting members 28 and 29 are adjacent to each other in the sheet width direction. The second restricting members 28 and 29 are positioned to overlap with the upstream loading section 63a with respect to the sheet transport direction. The second restricting members 28 and 29 are exposed to the outside from the lower discharge port 85 when the tray unit 110 is positioned in the second position (see Figure 9).

[0077] Since the second regulating members 28 and 29 are symmetrical in the sheet width direction and have essentially the same configuration, only the second regulating member 28 will be described here, and the second regulating member 29 will be given the same reference numeral and its description will be omitted.

[0078] The second regulating member 28 comprises a downstream bottom surface 53, a rack gear 66, a downstream side wall portion 57, a downstream flat portion 54 (fixed guide plate), and a guide plate 55 (movable guide plate). The downstream bottom surface 53 is a surface parallel to the downstream loading surface 25. The downstream bottom surface 53 is located below the downstream loading surface 25. That is, when the sheet S is loaded on the sheet loading surface 62, the downstream bottom surface 53 is located further from the sheet S than the downstream loading surface 25.

[0079] The rack gear 66 extends along the sheet width direction from the downstream bottom surface 53 beyond the center of the downstream loading section 63b. The rack gear 66 of the second regulating member 28 and the rack gear 66 of the second regulating member 29 are opposite each other in the sheet conveying direction. A pinion gear 67 is positioned between the rack gear 66 of the second regulating member 28 and the rack gear 66 of the second regulating member 29. The pinion gear 67 is rotatably supported by the downstream loading section 63b.

[0080] The rack gear 66 and pinion gear 67 of the second restricting members 28 and 29 engage with each other to form a rack and pinion mechanism. The pinion gear 67 is connected to a drive unit such as a motor (not shown) and rotates due to the rotational driving force output by this drive unit. As the pinion gear 67 rotates, the second restricting members 28 and 29 reciprocate via the rack gear 66, moving closer to or further away from each other along the seat width direction.

[0081] The downstream side wall portion 57 is a plate-like portion perpendicular to the downstream bottom surface 53. The downstream side wall portion 57 is connected to the outer edge of the downstream bottom surface 53 in the sheet width direction (opposite the center of the downstream loading surface 25 in the sheet width direction).

[0082] As the second restricting members 28 and 29 move closer to each other in the sheet width direction, and the downstream side walls 57 of the second restricting members 28 and 29 come into contact with both ends of the sheet S in the sheet width direction that is loaded on the downstream loading surface 25, both ends of the sheet S are aligned (aligned) at a predetermined position in the sheet width direction.

[0083] The downstream flat portion 54 is a plate-like portion parallel to the downstream bottom surface 53. The downstream flat portion 54 extends from the edge of the downstream side wall portion 57 in the direction opposite to the sheet loading direction toward the inside in the sheet width direction (towards the center of the downstream loading surface 25 with respect to the sheet width direction). The downstream flat portion 54 faces the downstream bottom surface 53 with respect to the sheet loading direction.

[0084] The guide plate 55 is a plate-shaped member formed in an elongated shape along the sheet conveying direction. The guide plate 55 is supported on the downstream side wall portion 57 so as to be able to swing along the circumferential direction of the pivot shaft 56, which extends parallel to the sheet width direction. The guide plate 55 is located downstream of the downstream flat portion 54 with respect to the sheet conveying direction. The guide plate 55 is located in a position that overlaps with the downstream flat portion 54 with respect to the sheet width direction.

[0085] The guide plate 55 has a support portion 58 and a lifting portion 59. The support portion 58 is the upstream end of the guide plate 55 with respect to the sheet transport direction. The lifting portion 59 is the downstream end of the guide plate 55 with respect to the sheet transport direction. The support portion 58 faces the downstream side wall portion 57 with respect to the sheet width direction.

[0086] Figure 13 is a cross-sectional view of the second restricting member 28 located at the restricting position P1, perpendicular to the sheet width direction. Figure 14 is a cross-sectional view of the second restricting member 28 located at the retracted position P2, perpendicular to the sheet width direction. Figure 15 is a cross-sectional view of the second restricting member 28 in contact with the lifting section 59 of the sheet S loaded on the downstream loading surface 25, perpendicular to the sheet width direction.

[0087] As shown in Figures 11 to 14, the pivot shaft 56 passes through the downstream side wall 57 and the support 58 along the sheet width direction and is fixed to the downstream side wall 57. The pivot shaft 56 passes through the support 58 with a small gap between them. The support 58 is pivotable in the circumferential direction about the pivot shaft 56. The lifting section 59 moves closer to (down) or further away from (up) the downstream loading surface 25 and the downstream bottom surface 53 as the guide plate 55 swings along the circumferential direction of the pivot shaft 56.

[0088] The guide plate 55 swings between a restricted position P1 and a retracted position P2. The restricted position P1 is the position where the lifting section 59 is closer to the downstream loading surface 25 than the downstream flat section 54 with respect to the sheet loading direction (the position shown in Figure 13). At this time, the distance L1 between the lifting section 59 and the downstream loading surface 25 is smaller than the distance L2 between the downstream flat section 54 and the downstream loading surface 25. The guide plate 55 is positioned at the restricted position P1 by its own weight while not in contact with the sheet S.

[0089] The retracted position P2 is the position where the lifting section 59 is further away from the downstream loading surface 25 than the downstream flat section 54 with respect to the sheet loading direction (the position shown in Figure 14). At this time, the distance L1' between the lifting section 59 and the downstream loading surface 25 is greater than the distance L2 between the downstream flat section 54 and the downstream loading surface 25. When the leading edge of the sheet S loaded on the downstream loading surface 25 (the downstream end in the sheet transport direction) comes into contact with the vicinity of the lifting section 59 of the guide plate 55, the guide plate 55 is biased toward the retracted position P2.

[0090] As shown in Figure 15, the sheet S being transported to the downstream loading section 63b is transported between the downstream flat section 54 and the guide plate 55 and the sheet loading surface 62 in the sheet loading direction. If the leading edge of the sheet S (the downstream end in the sheet transport direction) is curled, the lifting section 59 comes into contact with the sheet S. At this time, the curled portion of the sheet S presses the lifting section 59 upward. Conversely, the guide plate 55, by its own weight, presses down on the curled portion against the pressing force of the sheet S. As a result, the curl of the sheet S is corrected. At this time, the guide plate 55 is biased from the restricted position P1 towards the retracted position P2 by the restoring force generated in the curled portion of the sheet S.

[0091] As shown by the dashed line in Figure 15, if the curl of the sheet S is not corrected, the leading edge of the sheet S will be rewound towards the trailing edge. If the lower moving member 652 were to come into contact with the sheet S in this state, the lower moving member 652 would come into contact with the curled portion of the sheet S. This would make it difficult to accurately position the sheet S in the sheet transport direction.

[0092] On the other hand, in the present invention, by configuring the sheet folding device 60 as in the above embodiment, as described above, when the guide plate 55 is in the restricted position P1, the distance L1 between the sheet S and the lifting unit 59 is smaller than the distance L2 between the sheet S and the downstream flat section 54. Therefore, the sheet S transported to the sheet loading unit 63 is positioned closer to the lifting unit 59 than to the downstream flat section 54. Then, even if the leading edge of the sheet S is curled, it becomes possible to correct the curl by contact with the lifting unit 59. Furthermore, it becomes possible to correct the curl more strongly than by contact with the downstream flat section 54. Therefore, the downward moving member 652 can contact the leading edge of the sheet S and more accurately position the sheet S in the sheet transport direction. Thus, it is possible to provide a sheet folding device 60 that can suppress misalignment of the sheet S in the sheet transport direction when it is loaded onto the sheet loading unit 63.

[0093] Furthermore, as described above, the guide plate 55 is positioned at the restricted position P1 by its own weight without being in contact with the sheet S. Alternatively, the guide plate 55 corrects the curl of the sheet S by its own weight while in contact with it. Therefore, it becomes possible to correct the curl of the sheet S by oscillating the guide plate 55 without using a complex configuration.

[0094] Furthermore, as described above, the second restricting members 28 and 29 are exposed to the outside through the lower discharge port 85 when the tray unit 110 is positioned in the second location. This makes it easier to remove the sheets S from the downstream loading surface 25, for example, if a paper jam occurs on the sheet loading surface 62.

[0095] Furthermore, as described above, when the guide plate 55 is in the retracted position P2, the distance L1' between the lifting section 59 and the downstream loading surface 25 is greater than the distance L2 between the downstream flat section 54 and the downstream loading surface 25. Therefore, it is easier to remove the sheet S from the downstream loading surface 25.

[0096] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, although the above embodiments show an example in which the sheet folding device 60 includes a first folding device 70 and a second folding device 90, the present invention is not limited to this, and the sheet folding device 60 does not necessarily have to include the second folding device 90.

[0097] Furthermore, although a multifunction printer is given as an example of the image forming apparatus 10 in the above embodiment, other image forming apparatuses (such as laser printers, inkjet printers, facsimile machines, etc.) may also be used. [Industrial applicability]

[0098] The present invention can be used in an image forming system that combines an image forming apparatus with a sheet post-processing apparatus that performs post-processing such as binding on sheets that have been image-formed by the image forming apparatus. By using the present invention, it is possible to provide a sheet folding apparatus that can suppress misalignment of the sheet in the sheet transport direction when sheets are loaded onto a sheet loading unit, a sheet post-processing apparatus equipped therewith, and an image forming system. [Explanation of Symbols]

[0099] 1. Image forming system 10 Image forming apparatus 18 Image forming unit 20 Post-processing mechanism 24 Upstream loading surface 25 Downstream loading surface 30 Sheet Post-Processing Device 32 Sheet transport path 54 Downstream flat area (flat area) 55 Guide plate 59 Lifting section 60 Sheet Folding Machine 62-seat loading surface 63-seat loading unit 63a Upstream loading section 63b Downstream loading section 65. Alignment member (sheet alignment section) 653a Upstream width adjustment member (upstream alignment section) 653b Downstream width adjustment member (downstream alignment section) 70. First folding device (folding processing unit) 86 Discharge Roller 90. Second folding device (folding processing unit) 651 Upper moving member (first claw portion) 652 Downward moving member (second claw portion) P1 Restriction location P2 Evacuation position

Claims

1. A sheet loading unit on which sheets that have passed through the sheet transport path are loaded, A folding processing unit having a pair of folding rollers, which performs a predetermined folding process on the sheets loaded in the sheet loading unit by nipping them with the pair of folding rollers, A discharge roller is positioned downstream of the folding unit with respect to the sheet transport direction and discharges the folded sheet downstream in the sheet transport direction, Equipped with, The aforementioned sheet loading unit is A sheet loading tray on which the aforementioned sheets are loaded, A sheet alignment unit is supported on the sheet stacking tray so as to be able to reciprocate in the sheet width direction perpendicular to the sheet transport direction, and contacts the sheet stacked on the sheet stacking unit to position it in the sheet width direction, A sheet moving unit is supported on the sheet loading tray so as to be able to reciprocate in the sheet transport direction, and moves the sheets loaded on the sheet loading unit to a predetermined position in the sheet transport direction. It has, The aforementioned sheet loading tray is The pair of folding rollers is positioned with a gap in between, facing the nip portion, and is located on the upstream side in the sheet transport direction, and includes an upstream loading section with an upstream loading surface, It is positioned downstream in the sheet transport direction with the aforementioned gap in between, and has a downstream loading section including a downstream loading surface, The aforementioned sheet alignment unit is An upstream alignment portion that contacts the portion of the sheet loaded on the upstream loading portion of the sheet and positions it in the width direction of the sheet, It has a downstream alignment portion that abuts against the portion of the sheet loaded on the downstream loading portion and positions it in the width direction of the sheet, The downstream alignment section has a pair of regulating members adjacent to each other in the sheet width direction, The pair of regulating members are movable in the sheet width direction and abut against both side edges of the sheet in the sheet width direction to position them in the sheet width direction. Each of the aforementioned restricting members is A side plate that stands upright with respect to the downstream loading surface and abuts against the side surface of the sheet, A fixed guide plate is provided on the upstream side of the side plate in the sheet transport direction, so as to face the downstream loading surface at a predetermined height, and which restricts the upper surface of the sheet. A movable guide plate is provided downstream of the fixed guide plate with respect to the sheet transport direction, and the portion upstream of the center in the sheet transport direction is located above the fixed guide plate at a pivot point, and the movable guide plate is supported by the side plate so as to be able to swing between a retracted position in which the downstream end in the sheet transport direction is located above the portion of the fixed guide plate closest to the downstream loading surface, and a restricting position in which the downstream end in the sheet transport direction is located below the portion of the fixed guide plate closest to the downstream loading surface, thereby restricting the upper surface of the sheet. It has, The sheet folding device is characterized in that the fixed guide plate is connected to the side plate and extends inward from the side plate in the sheet width direction.

2. The aforementioned seat moving part is The first claw portion is arranged to be reciprocally movable along the sheet transport direction on the upstream loading surface and contacts the upstream end of the sheet loaded on the sheet loading unit, A second claw portion is arranged on the downstream loading surface so as to be able to reciprocate along the sheet transport direction and contacts the downstream end of the sheet loaded on the sheet loading unit, The sheet folding device according to claim 1, characterized in that it has a first claw portion and a second claw portion that grip the sheet and position the sheet in the sheet conveying direction.

3. The sheet folding device according to claim 1 or 2, characterized in that the movable guide plate is positioned in the restricted position by its own weight when not in contact with the sheet, is pushed up when it comes into contact with the sheet, and swings upward from the restricted position.

4. The aforementioned folding unit is The sheet folding device according to claim 1 or 2, further comprising a folding blade that faces the nip portion of the folding roller pair, is positioned between the upstream loading portion and the downstream loading portion with respect to the sheet transport direction, and presses the portion of the sheet loaded on the sheet loading unit, including the center in the sheet transport direction, through the gap to insert the sheet into the nip portion of the folding roller pair.

5. A first transport path for transporting the sheet brought in from the entrance, A second transport path transports the sheet that has been transported from the first transport path to the sheet transport path, A first processing unit performs predetermined post-processing on the sheet that has been transported along the first transport path, and transports the sheet that has undergone the post-processing to a second transport path or to a discharge tray on which the sheet can be loaded. A sheet folding device according to claim 1 or 2, A sheet post-processing device characterized by comprising the following:

6. A sheet post-processing device according to claim 5, An image forming apparatus connected to the sheet post-processing apparatus, which forms an image on the sheet and transports the image-formed sheet to the sheet post-processing apparatus, An image forming system characterized by comprising the following features.

7. A conveying unit that transports sheets, A sheet loading unit having a loading surface for loading the sheets transported from the transport unit, A sheet moving unit is supported on the loading surface so as to be able to reciprocate in the sheet transport direction, and contacts the sheet loaded on the sheet loading unit to position the sheet at a predetermined position in the sheet transport direction. A sheet alignment unit is supported on the loading surface so as to be able to reciprocate in the sheet width direction perpendicular to the sheet transport direction, and positions the sheet loaded on the sheet loading unit at a predetermined position in the sheet width direction. Equipped with, The aforementioned sheet alignment unit is The sheet has a pair of cursors that are positioned opposite each other in the width direction of the sheet and are supported so as to be movable toward and away from each other, The aforementioned pair of cursors A side plate erected from the aforementioned loading surface and in contact with the side surface of the sheet, A fixed guide plate extends upward from the side plate in the direction of separation from the loading surface, upstream of the center of the side plate with respect to the sheet transport direction, A movable guide plate is positioned downstream of the fixed guide plate, pivotably supported by the side plate at a pivot point located above the fixed guide plate, and extending downstream from the pivot point in the sheet conveying direction to restrict the upper surface of the sheet. The fixed guide plate is fixed to the side plate, guides the sheet downstream, and regulates the loading height of the sheet. The movable guide plate is swingable between a restricting position where its downstream end in the sheet transport direction is lower than the portion of the fixed guide plate closest to the loading surface, and a retracted position where it is higher than the portion of the fixed guide plate closest to the loading surface. When in the restricting position, it restricts the loading height of the sheets at a position lower than the fixed guide plate. The sheet loading device includes a sheet moving section which is guided by the movable guide plate and positions the downstream end of the sheet, whose loading height is restricted, at a predetermined position in the sheet transport direction.

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