Sheet processing apparatus and image formation system

Abstract

To correctly guide a sheet to a nip part upon executing fold processing.SOLUTION: A sheet processing apparatus for executing fold processing to a sheet comprises: a rotating body pair 22 for holding a sheet with nip parts and executing rotation, thus pulling-in the sheet and executing fold processing; a pushing member 23 for pushing out the sheet into the nip parts of the rotating body pair; and a pushing guide member 40 having a guide part for pushing out the sheet into the nip parts when the pushing member pushes out the sheet into the nip parts. The pushing member and the pushing guide member are relatively moved so that a distance from a pushing tip part to the guide part when the pushing member pushes out the sheet into nip parts is made longer than a distance from the tip part to the guide part when the sheet begins to be pushed out.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present invention relates to a sheet processing apparatus for folding a sheet sent from, for example, an image forming apparatus, and an image forming system including the same. [Background technology]

[0002] Conventionally, there has been provided a sheet processing apparatus that folds a stack of sheets into a booklet as post-processing of sheets discharged from an image forming apparatus such as a copier, a printer, a facsimile, or a combination of these. For example, a sheet processing apparatus is known that folds a predetermined position of a sheet conveyed from an image forming apparatus to a sheet stacker with a butting plate, pushes the sheet into a nip between a pair of folding rollers, and folds the sheet in half while conveying it with the pair of folding rollers.

[0003] Among sheet processing devices that perform folding processing on sheets, there are sheet processing devices that not only fold in half, but also fold the sheet in two different places and perform an inner triple fold process in which one edge of the sheet is on the inside of the folded sheet.

[0004] When performing the above-mentioned inner triple fold process, when the abutment pushes the sheet into the nip between the pair of folding rollers for the second fold process, the edge of the sheet that has been folded in half in the first fold process may curl up.

[0005] To prevent this, a configuration has been proposed in which a curl prevention member having a shape that follows the outer diameter of the folding roller is integrally provided on the abutment plate, and when the sheet is struck with the abutment plate to perform the second folding process, the curl prevention member guides the edge of the sheet to be folded into the nip portion, thereby preventing the edge from curling up (Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2012-056674 Summary of the Invention [Problem to be solved by the invention]

[0007] In the above-mentioned Patent Document 1, the curl-preventing member is used for the second folding process, but the curl-preventing member can be used not only for the second folding process but also for the first folding process (including normal folding in half) to guide the sheet to the pair of folding rollers. However, in the configuration of the above-mentioned Patent Document 1, when the abutting plate protrudes to the vicinity of the nip part of the pair of folding rollers, it is necessary to secure a distance from the tip of the abutting plate so that the curl-preventing member does not hit the outer periphery of the folding rollers. This distance becomes longer as the diameter of the folding rollers becomes larger.

[0008] If the distance between the tip of the abutting plate and the curl prevention member becomes long, the timing at which the curl prevention member guides the sheet when the abutting plate starts to push the sheet will be delayed, which may cause a loss in sheet transport until the curl prevention member comes into contact with the sheet, and may cause the sheet to crease.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a sheet processing device that can accurately guide a sheet to a nip portion when performing a folding process, and an image forming system equipped with the same. [Means for solving the problem]

[0010] A representative configuration of the present invention for achieving the above object is a sheet processing apparatus that performs a first folding process on a sheet, and then performs a second folding process at a position different from the crease formed by the first folding process, so that one end of the sheet folded by the first folding process is inside the folded sheet. The sheet processing apparatus includes a conveying path having a guide surface that guides a conveyed sheet, a pair of rotating bodies that pinch the sheet conveyed to the conveying path at a nip portion and rotate to pull in the sheet and perform a folding process, and a tip portion that protrudes the sheet conveyed to the conveying path toward the nip portion of the pair of rotating bodies, and a first position where the tip portion is retracted from the conveying path, a second position where the tip portion protrudes into the conveying path by a predetermined amount, and a second position where the tip portion is moved toward the sheet. a protruding member movable between a first position and a second position where the protruding member protrudes the sheet into the nip portion of the pair of rotating bodies, a protruding guide member having a guide portion that pushes the one end of the sheet folded by the first folding process closer to the pair of rotating bodies when the protruding member protrudes the sheet into the nip portion when performing the second folding process, and a moving means that moves the protruding member and the protruding guide member in a protruding direction in which they protrude toward the nip portion and a return direction that is the opposite direction, wherein the moving means moves the protruding member and the protruding guide member relatively so that the distance from the tip portion to the guide portion at the third position is longer than the distance from the tip portion to the guide portion at the second position.

[0011] Moreover, the present invention provides a sheet processing apparatus that performs a first folding process on a sheet, and then performs a second folding process at a position different from the crease formed by the first folding process, so that one end of the sheet folded by the first folding process is inside the folded sheet, the sheet processing apparatus comprising: a support section that supports the sheet; a pair of folding rollers that clamp the sheet supported by the support section in a nip section and rotate to pull in the sheet and perform a folding process; a pushing member that pushes the sheet supported by the support section in a pushing direction toward the nip section; a pushing member that pushes the one end of the sheet folded by the first folding process closer to the pair of folding rollers when the pushing member pushes the sheet into the nip section when performing the second folding process; and a moving mechanism that moves both the pushing member and the pushing member in the pushing direction, stops the pushing member before the pushing member reaches the pair of folding rollers in the pushing direction, and moves the pushing member further in the pushing direction after the pushing member has stopped. Effect of the Invention

[0012] According to the present invention, the sheet can be pushed out by the pushing guide member even after the sheet is guided to the vicinity of the pair of rotating bodies by the pushing guide member, so that the sheet can be pushed out into the nip portion and guided accurately. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram of an overall configuration of an image forming system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is an explanatory diagram of an overall configuration of a sheet processing apparatus in an image forming system. [Diagram 3] FIG. 2 is a cross-sectional view showing a folding processing device of the sheet processing device. [Figure 4] FIG. [Diagram 5] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 6] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 7] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 8] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 9] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 10] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 11] 13(a) and (b) are cross-sectional views illustrating the inward three-folding operation of a sheet. [Figure 12] FIG. [Figure 13] 4 is an explanatory diagram of the arrangement of a pair of folding rollers, a folding blade, and a pressing guide member. FIG. [Figure 14] (a)(b)(c) Illustrative diagram of the operation of the pressure guide member [Figure 15] 4A and 4B are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 16] 4A and 4B are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 17] 4A and 4B are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 18] 4A and 4B are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 19] 4A and 4B are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 20] FIG. 4 is a control block diagram of a folding operation in the sheet folding processing device. [Figure 21] 4 is a flowchart of a folding operation in the sheet folding processing device. [Figure 22] 4 is a flowchart of a folding operation in the sheet folding processing device. [Diagram 23] FIG. [Figure 24] 4A, 4B, and 4C are top view explanatory diagrams of the operation of the folding blade and the blade guide member. [Diagram 25] 11A to 11C are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 26] 11A to 11C are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 27] 11A to 11C are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 28] 11A to 11C are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Figure 29] 11A to 11C are cross-sectional explanatory views of the operation of the folding blade and the blade guide member. [Diagram 30] 4A and 4B are cross-sectional explanatory views of a deflection guide member. [Diagram 31] 4A and 4B are cross-sectional explanatory views of a deflection guide member. [Diagram 32] 4A and 4B are cross-sectional explanatory views of a deflection guide member. [Diagram 33] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Next, a sheet processing apparatus according to a preferred embodiment of the present invention and an image forming system including the same will be described with reference to the drawings. Fig. 1 shows a schematic diagram of the overall configuration of an image forming system including a sheet processing apparatus according to an embodiment of the present invention. As shown in the figure, the image forming system 100 is composed of an image forming apparatus A and a sheet processing apparatus B attached thereto.

[0015] <Overall configuration of image forming apparatus> The image forming apparatus A is made up of an image forming unit A1, a scanner unit A2, and a feeder unit A3. The image forming unit A1 includes a feeding section 2, an image forming section 3, a discharge section 4, and a data processing section 5 inside a device housing 1.

[0016] The feeding section 2 is composed of multiple cassette mechanisms 2a, 2b, and 2c that store image formation sheets of different sizes, and feeds out sheets of a size specified by a main body control unit (not shown) to a feeding path 2f. Each cassette mechanism 2a, 2b, and 2c is installed detachably from the feeding section 2, and each has a built-in separation mechanism that separates the internal sheets one by one and a feeding mechanism that feeds out the sheets. The feeding path 2f is provided with a conveying roller that feeds the sheets supplied from each cassette mechanism 2a, 2b, and 2c downstream, and a pair of registration rollers at the end of the path that aligns the leading edge of each sheet.

[0017] A large-capacity cassette 2d and a manual feed tray 2e are connected to the feeding path 2f. The large-capacity cassette 2d is an optional unit that stores sheets of a size that are consumed in large quantities. The manual feed tray 2e is configured to be able to feed special sheets such as thick paper sheets, coated sheets, and film sheets that are difficult to separate and feed.

[0018] In this embodiment, the image forming unit 3 is configured using an electrophotographic system and includes a rotating photosensitive drum 3a, a light emitter 3b that emits an optical beam, a developing unit 3c, and a cleaner (not shown) that are arranged around the photosensitive drum 3a. What is shown in the figure is a monochrome printing mechanism, in which the photosensitive drum 3a, the peripheral surface of which is uniformly charged, is irradiated with light by the light emitter 3b in response to an image signal to optically form a latent image, and the developing unit 3c attaches toner to this latent image to form a toner image.

[0019] In accordance with the timing of image formation on the photosensitive drum 3a, a sheet is sent from the feeding path 2f to the image forming unit 3, and the toner image formed on the photosensitive drum 3a is transferred onto the sheet by applying a transfer bias from the transfer charger 3d. The sheet onto which the toner image has been transferred is heated and pressurized as it passes through the fixing device 6 to fix the toner image, and is discharged from the discharge port 4b by the discharge rollers 4a and transported to the sheet processing device B described later.

[0020] The scanner unit A2 includes a platen 7a on which an image document is placed, a carriage 7b that reciprocates along the platen 7a, a photoelectric conversion means 7c, and a reduction optical system 7d that guides the light reflected from the document on the platen 7a by the carriage 7b to the photoelectric conversion means 7c. The photoelectric conversion means 7c photoelectrically converts the optical output from the reduction optical system 7d into image data and outputs it to the image forming unit 3 as an electrical signal.

[0021] The scanner unit A2 also includes a traveling platen 7e to read sheets fed from the feeder unit A3. The feeder unit A3 is composed of a feed tray 8a on which original sheets are stacked, a feed path 8b that guides the original sheets fed from the feed tray 8a to the traveling platen 7e, and a discharge tray 8c that stores the original sheets that have passed the traveling platen 7e. The original sheets from the feed tray 8a are read by the carriage 7b and the reduction optical system 7d as they pass the traveling platen 7e.

[0022] <Overall configuration of sheet processing device> Next, the overall configuration of the sheet processing apparatus B that performs post-processing on the sheets sent from the image forming apparatus A will be described.

[0023] 2 is a diagram illustrating the configuration of the sheet processing apparatus B according to this embodiment. The sheet processing apparatus B includes an apparatus housing 11 having an inlet 10 for introducing a sheet from the image forming apparatus A. The apparatus housing 11 is positioned in alignment with the housing 1 of the image forming apparatus A so that the inlet 10 communicates with the discharge port 4b of the image forming apparatus A.

[0024] The sheet processing apparatus B includes a sheet carry-in path 12 for transporting a sheet introduced from an entrance 10, a first discharge path 13a, a second discharge path 13b, and a third discharge path 13c branched off from the sheet carry-in path 12, a first path switching means 14a, and a second path switching means 14b. The first path switching means 14a and the second path switching means 14b are each formed of a flapper guide for changing the transport direction of a sheet transported through the sheet carry-in path 12.

[0025] The first path switching means 14a is switched by a driving means (not shown) between a mode in which the sheet from the carry-in entrance 10 is guided to the first discharge path 13a which transports the sheet horizontally as it is and the second discharge path 13b which transports the sheet downward, and a mode in which the sheet is guided to the third discharge path 13c which transports the sheet upward. The first discharge path 13a and the second discharge path 13b are connected so that a sheet once introduced into the first discharge path 13a can be switched back and transported to the second discharge path 13b by reversing the transport direction.

[0026] The second path switching means 14b is disposed downstream of the first path switching means 14a with respect to the conveying direction of the sheet conveyed through the sheet carry-in path 12. The second path switching means 14b is switched by a driving means (not shown) between a mode in which the sheet that has passed through the first path switching means 14a is introduced into the first discharge path 13a and a mode in which the sheet that has once been introduced into the first discharge path 13a is switched back and conveyed to the second discharge path 13b.

[0027] The sheet processing apparatus B includes a first processing section B1, a second processing section B2, and a third processing section B3, each of which performs a different post-processing. Further, a punch unit 15 is disposed in the sheet carrying-in path 12, which punches holes in the carried-in sheets.

[0028] The first processing section B1 is a binding processing section that accumulates, collates, and binds a plurality of sheets discharged from a discharge port 16a at the downstream end of the first discharge path 13a in relation to the conveying direction of the sheets conveyed through the sheet carry-in path 12, and discharges the sheets to a stacking tray 16b provided outside the device housing 11. The first processing section B1 also includes a sheet conveying device 16c that conveys a sheet or a sheet stack, and a binding processing unit 16d that binds the sheet stack. A pair of discharge rollers 16e is provided at the downstream end of the first discharge path 13a to discharge the sheets from the discharge port 16a and to switch back and convey the sheets from the first discharge path 13a to the second discharge path 13b.

[0029] The second processing section B2 is a folding processing section that forms a sheet bundle from a plurality of sheets conveyed in a switchback manner from the second discharge path 13b, binds the sheet bundle, and then folds the sheet bundle. As described later, the second processing section B2 includes a folding processing device F that folds the conveyed sheets or sheet bundle, and a binding processing unit 17a that is disposed immediately upstream of the folding processing device F along the sheet conveying direction of the sheets conveyed to the second discharge path 13b and binds the sheet bundle. The folded sheet bundle is discharged by discharge rollers 17b to a stacking tray 17c provided outside the device housing 11.

[0030] The third processing section B3 performs jog sorting to separate the sheets sent from the third discharge path 13c into a group that is accumulated by offsetting the sheets by a predetermined amount in the sheet width direction perpendicular to the conveying direction, and a group that is accumulated without offsetting the sheets. The jog sorted sheets are discharged to a stacking tray 18 provided outside the device housing 11, and the offset sheet bundle and the non-offset sheet bundle are stacked.

[0031] 3 shows a schematic overall configuration of the second processing section B2. As described above, the second processing section B2 includes a folding processing device F that folds the sheet bundle that is carried in from the second discharge path 13b and that is accumulated and collated in half, and a binding processing unit 17a that binds the sheet bundle before folding. The binding processing unit 17a shown in the figure is a stapler device that staples the sheet bundle to bind it.

[0032] A sheet transport path 20 is connected to the second discharge path 13b in order to carry the sheet into the folding processing device F. In the transport direction of the sheet transported from the second discharge path 13b to the sheet stacking tray 21, the sheet stacking tray 21 constituting a part of the sheet transport path 20 is provided downstream of the sheet transport path 20 in order to position and stack the sheet to be folded. Immediately upstream of the sheet stacking tray 21, the binding processing unit 17a and its staple receiving portion 17d are provided in opposing positions across the sheet transport path 20.

[0033] On one side of the sheet stacking tray 21, a pair of folding rollers 22 as a pair of folding rotating bodies are arranged so as to face one surface of a sheet or a sheet bundle to be stacked on the sheet stacking tray. The pair of folding rollers 22 is composed of a pair of folding rollers 22a, 22b whose roller surfaces are pressed against each other, and a nip portion 22c, which is a pressing portion, is arranged facing the sheet stacking tray 21. The folding rollers 22a, 22b are arranged in parallel with the sheet stacking tray 21 at approximately equal intervals on the upstream side and the downstream side along the conveying direction of the sheet conveyed from the upper upstream side to the lower downstream side into the sheet stacking tray 21. In the present invention, the rotating portion of the pair of folding rotating bodies is not limited to the folding rollers 22a, 22b of this embodiment, and may be composed of a rotating belt or the like. Furthermore, the pair of folding rollers 22 may be configured by continuously arranging a plurality of folding rollers (rotating bodies) in series along the axial direction of each of the folding rollers 22a, 22b.

[0034] As shown in Fig. 3, each of the folding rollers 22a and 22b of the pair of folding rollers 22 of this embodiment has a first roller surface 22a2 and 22b2 whose roller circumferential surface has a constant radius R1 centered on the rotation axis of the rotation shaft 22a1 and 22b1, and a second roller surface 22a3 and 22b3 whose distance from the rotation axis of the rotation shaft is smaller than the radius R1 of the first roller surface. The first roller surface 22a2 and 22b2 are formed of a rubber material or the like having a relatively high friction coefficient, like a normal roller surface. In contrast, the second roller surface 22a3 and 22b3 are formed of a plastic resin material or the like having a smaller friction coefficient than the first roller surface 22a2 and 22b2.

[0035] Rotation shafts 22a1, 22b1 of folding rollers 22a, 22b are rotated by a common driving means such as a driving motor, etc. This allows the rotational positions of first roller surfaces 22a2, 22b2 and second roller surfaces 22a3, 22b3 to be always synchronized with each other.

[0036] A folding blade 23 serving as a protruding member is disposed on the opposite side of the folding roller pair 22 across the sheet stacking tray 21. The folding blade 23 is supported by a blade carrier 24 with its tip facing the nip portion 22c of the folding roller pair 22. The blade carrier 24 is provided so as to be movable by a moving means constituted by a cam member or the like in a direction crossing the sheet stacking tray 21 at a substantially right angle, that is, in a direction intersecting the conveying direction of the sheet conveyed from the second discharge path 13b to the sheet stacking tray 21.

[0037] 3, i.e., in the axial direction of the folding rollers, a pair of cam members 25 (only one of which is shown in the figure) consisting of mirror-symmetric eccentric cams are provided at opposing positions on both sides of the blade carrier 24. The cam member 25 rotates around a rotation shaft 25a provided at the eccentric position by a driving means such as a driving motor. The cam member 25 has a cam groove 25b formed along its outer circumferential edge.

[0038] The blade carrier 24 is provided with a cam pin 24c serving as a cam follower, which is slidably fitted into the cam groove 25b.

[0039] When the drive motor rotates the cam member 25, the blade carrier 24 reciprocates in a direction approaching or receding from the sheet stacking tray 21. As a result, as shown in Fig. 3, between an initial position where the tip of the folding blade 23 does not enter the sheet conveying path formed by the sheet stacking tray 21 and a maximum protruding position where the tip of the folding blade 23 is sandwiched by the nip portion 22c of the pair of folding rollers 22, the folding blade 23 can be freely moved forward and backward in a straight line along a protruding path connecting both positions.

[0040] A regulating stopper 26 for restricting the leading edge of the conveyed sheet in the conveying direction by abutting against it is disposed at the lower end of the sheet stacking tray 21. The regulating stopper 26 is provided so as to be movable up and down along the sheet stacking tray 21 by a sheet lifting mechanism 27.

[0041] The sheet lifting mechanism 27 of this embodiment is disposed below the blade carrier 24 when the tip of the folding blade 23 is in an initial position behind the sheet stacking tray 21, which is a position where the tip of the folding blade 23 does not enter the sheet conveying path formed by the sheet stacking tray 21, and is a conveyor belt mechanism consisting of a pair of pulleys 27a, 27b disposed near the upper and lower ends of the sheet stacking tray 21 along the sheet stacking tray 21, and a transmission belt 27c wound around both pulleys. The regulating stopper 26 is fixed on the transmission belt 27c. By rotating the drive pulley 27a or 27b on the driving side by a driving means such as a driving motor, the regulating stopper 26 moves up and down between the lower end position shown in FIG. 3 and a desired height position, thereby allowing the sheet or sheet stack to be moved along the sheet stacking tray 21.

[0042] The folding device F of this embodiment further includes a sheet side alignment mechanism for aligning the side edges of the sheets fed into the sheet stacking tray 21. As shown in FIG. 4, the sheet side alignment mechanism has a pair of sheet side alignment members 28a, 28b arranged symmetrically on both sides of the sheet width direction (direction perpendicular to the sheet conveying direction) of the sheet stacking tray 21. FIG. 4 is a schematic plan view of the folding device F as seen from above. The sheet side alignment members 28a, 28b are held movably so that they can relatively approach and move away from each other in the sheet width direction. When a sheet is conveyed to the sheet stacking tray 21 and its leading edge hits the regulating stopper 26, the sheet side alignment members 28a, 28b are moved to align the sheet width direction.

[0043] <Inner triple folding process> The sheet processing device B of this embodiment is capable of folding a sheet in three after it has been conveyed to the sheet stacking tray 21, which serves as a sheet conveying path, by the folding device F. The folding in three is a process in which a sheet is folded in half by a first folding process, and then folded a second time at a position different from the initial folding position, so that one end of the sheet folded in the first folding process is folded inside the sheet folded in the second folding process, thereby folding the sheet in three. Here, the outline of the operation of the folding device F of this embodiment when folding in three will be described with reference to Figs. 5 to 11. Figs. 5 to 11 are schematic cross-sectional views showing the movement of each part along the flow of the sheet S when folding in three is performed.

[0044] The sheet stacking tray 21 of this embodiment is formed at an angle with respect to the vertical direction, and the sheet S is conveyed so as to fall with the sheet leading edge S1 facing down and the sheet trailing edge S2 facing up while being guided by the guide surface 21a that forms the sheet stacking tray 21 on one side, and the sheet leading edge hits the regulating stopper 26 and stops (FIG. 5(a)). At this time, the position of the regulating stopper 26 is arranged so that the first folding position of the sheet S against which the sheet leading edge S1 hits is a position facing the folding blade 23. The folding blade 23 is arranged at a position that pushes the sheet S from the side of the guide surface 21a of the sheet stacking tray 21 toward the folding roller pair 22. In other words, the guide surface 21a of the sheet stacking tray 21 and the folding roller pair 22 are arranged at corresponding positions with the sheet S sandwiched therebetween.

[0045] In this state, the sheet width direction position is aligned by the sheet side alignment members 28a, 28b described above, and then the folding blade 23 is operated to fold the sheet S in two and protrude the folded portion into the nip portion 22c of the folding roller pair 22 (FIG. 5(b)). In synchronization with the protruding operation of the folding blade 23, the folding roller pair 22 and the discharge roller 17b are driven in the forward direction to pull the sheet S into the folding roller pair 22 and the discharge roller 17b. As a result, the sheet S is pressed by the nip portion of the folding roller pair 22 and the first folding process is performed (FIG. 6(a)).

[0046] Next, in order to perform the second folding process, the sheet conveyance is stopped when the sheet trailing end S2, which has been folded the first time, reaches a predetermined position (FIG. 6(b)), and the pair of folding rollers 22 and the discharge roller 17b are driven in the reverse direction to perform the switchback conveyance process. The sheet trailing end S2 becomes the end (hereinafter referred to as the "folded end") that is folded inside the sheet folded by the second folding process when the sheet is folded in three. Then, when the switchback conveyance process is performed, the folded end S2 is pushed down (toward the sheet stacking tray 21 where the sheet leading end S1 is located) by the L-shaped pressing guide member 30 (FIG. 7(a)), and the pressing guide member 30 guides the sheet S conveyed again in the direction where the regulating stopper 26 of the sheet stacking tray 21 is arranged (FIG. 7(b)). The configuration and operation of the pressing guide member 30 will be described in detail later.

[0047] When the leading edge of the sheet S reaches the regulating stopper 26, which has been moved to the sheet receiving position in advance by the switchback transport (FIG. 8(a)), the pressing guide member 30 is returned to the retracted position and then moved to the reverse transport guide position (FIG. 8(b)), and the regulating stopper 26 is moved to a position where the second folding position faces the folding blade 23 (FIG. 9(a)). After the movement is completed, the pressing guide member 30 is moved to a guide position parallel to the guide surface 21a of the sheet stacking tray 21 (FIG. 9(b)).

[0048] Next, the folding blade 23 is operated again to push the sheet S into the nip portion 22c of the pair of folding rollers 22 (FIG. 10(a)). At this time, the blade guide member 40, which is a push-out guide member arranged above the folding blade 23, protrudes to guide the folded end S2 of the sheet so as to be pushed into the nip portion 22c (FIG. 10(b)). The configuration and operation of this blade guide member 40 will be described in detail later.

[0049] The sheet S is sent to the pair of folding rollers 22 by the protrusion of the folding blade 23, and is folded a second time by passing through the nip portion 22c (Figure 11(a)), and the sheet S folded in three is discharged by the discharge roller 17b (Figure 11(b)).

[0050] <Pressure guide member> Next, the pressing guide member 30, which is the pressing member described above, will be described with reference to Figs. 12 to 14. Fig. 12 is a perspective view of the folding device F with the pressing guide member 30 exposed, and Fig. 13 is a diagram showing the rotation trajectory of the pressing guide member 30 and its relationship with other members. Fig. 14 is an explanatory diagram of the operation of the pressing guide member 30.

[0051] (Shape of pressure guide member) The pressing guide member 30 presses the folded end S2 of the sheet downward when the sheet on which the first folding process has been performed is switched back and conveyed, and guides the sheet so as to be conveyed to the sheet stacking tray 21. In other words, the pressing guide member 30 is also a direction changing member that changes the orientation of the folded end S2 of the sheet to the direction of the sheet tip S1 of the sheet stacking tray 21 when the sheet on which the first folding process has been performed is switched back and conveyed.

[0052] 12 (and FIG. 4), the pressing guide members 30 are disposed on the opposite side to the side where the folding roller pair 22 is disposed, with the sheet S guided by the guide surface 21a of the sheet stacking tray 21 sandwiched therebetween. In this embodiment, three pressing guide members 30 are attached in a line at approximately equal intervals to a rotating shaft 31, which is a support member disposed in the sheet width direction. Two on both sides are disposed at positions where they can abut on both ends of the sheet S transported on the sheet stacking tray 21, and the central one is disposed at a position where it can abut on approximately the center in the width direction of the transported sheet.

[0053] The pressing guide member 30 can be moved by a moving means. In this embodiment, the rotating shaft 31 is connected to the pressing guide motor 33 via a drive transmission member 32 such as a drive belt, and the rotating shaft 31 rotates when driven by the pressing guide motor 33, and the three pressing guide members 30 can rotate integrally with the rotating shaft 31.

[0054] 13, the pressing guide member 30 has a rotating portion 30a that can rotate around a rotating shaft 31, and a guide portion 30b that serves as a first guide surface that guides the sheet S being conveyed in a switchback manner, and is configured as a member with an L-shaped cross section in which the guide portion 30b is connected to the rotating portion 30a at a substantially right angle. The portion between the rotating portion 30a and the guide portion 30b, i.e., the corner of the L-shape that is the tip of the rotating portion 30a, is formed as a pressing portion 30c that presses the sheet S.

[0055] The pressing guide member 30 is provided so as to be exposed from a notch formed in the guide surface 21a. When the sheet S is carried into the sheet stacking tray 21, the pressing guide member 30 is retracted to a retracted position (see FIG. 5(a)). When in this retracted position, the rotating portion 30a is provided so as to be substantially flush with the guide surface 21a. Therefore, the rotating portion 30a functions as a part of the guide surface 21a and acts as a guide surface (second guide surface) that guides the sheet carried into the sheet stacking tray 21. When the pressing guide member 30 is in the retracted position, it is only necessary to prevent the guide portion 30b from protruding from the guide surface 21a, so that the storage space for the pressing guide member 30 in the retracted state can be reduced.

[0056] (Position of center of rotation) 13, the rotation shaft 31 which is the rotation center of the pressing guide member 30 of this embodiment is disposed upstream of the nip line L1 connecting the nip portion 22c of the folding roller pair 22 and the tip of the folding blade 23 in the conveying direction in which the sheet S is carried into the sheet stacking tray 21, and is disposed on the opposite side to the side on which the folding roller pair 22 is disposed across the guide surface 21a of the sheet stacking tray 21. Furthermore, the rotation shaft 31 of this embodiment passes through the rotation shaft 22a1 of the folding roller 22a, which is disposed upstream of the nip line L1 in the sheet conveying direction among the folding rollers 22a and 22b, i.e., the folding roller 22a located closer to the rotation shaft 31, and is disposed downstream of the axis L2 parallel to the nip line L1 in the conveying direction.

[0057] The rotating portion 30a is set so as to rotate in a direction in which the pressing portion 30c presses the sheet S toward the side where the sheet S is switched back and conveyed.

[0058] Therefore, when the sheet S on which the first folding process has been performed is switched back and conveyed, as shown in FIG. 14(a), the pressing guide member 30 at the retreat position rotates, and as shown in FIG. 14(b), the pressing portion 30c presses the folding end S2 of the sheet downward from above the folding end S2. As a result, the folding end S2 is guided to the downstream side (downward) of the sheet conveying direction where the sheet S is received on the sheet stacking tray 21 before the first folding process of the sheet stacking tray 21 while being switched back and conveyed. That is, the pressing portion 30c changes the orientation of the folding end S2 of the sheet to the direction of the sheet leading end S1 of the sheet stacking tray 21. After changing the orientation of the folding end S2, the pressing guide member 30 remains at that position, thereby being able to guide the folding end S2 to the downstream side of the sheet conveying direction where the sheet S is received on the sheet stacking tray 21 before the first folding process.

[0059] 14(c), when the pressing portion 30c rotates to the guide position where it is rotated to the position of the guide surface 21a, the pressing portion 30c abuts against the sheet and then presses down so as to pull the folded end S2 of the sheet from the nip portion 22c side to the guide surface 21a side, and guides the sheet in the direction in which the regulating stopper 26 of the sheet stacking tray 21 is disposed. Therefore, even if the folded end S2 of the sheet is curled upward, the sheet will not proceed upward on the sheet stacking tray 21, but will be reliably transported downward.

[0060] (Rotation area of ​​the rotating part) The length of the rotating portion 30a of the pressing guide member 30 in this embodiment, i.e., the length from the rotating shaft 31, which is the rotation fulcrum, to the pressing portion 30c, is set to be longer than the shortest distance to the first roller surface 22a2 of the folding roller 22a closer to the rotating shaft 31 of the two folding rollers 22a, 22b, and shorter than the shortest distance to the second roller surface 22a3, as shown in Figure 13.

[0061] As described above, even if the length of the rotating portion 30a is set longer than the shortest distance to the first roller surface 22a2, by stopping the folding roller pair 22 so that the second roller surfaces 22a3, 22b3 face the rotating portion 30a when the sheet switches back, the rotating portion 30a does not interfere with the folding roller pair 22 even when it is rotated. Moreover, since the rotating portion 30a can be set longer than the shortest distance to the first roller surface 22a2, which is the large diameter portion of the folding roller 22a, the pressing portion 30c presses the sheet being switched back and conveyed at a position closer to the nip portion 22c, so that the sheet is more reliably guided to the sheet stacking tray 21.

[0062] When the rotating portion 30a is lengthened, the rotating shaft 31 must be disposed at a position away from the folding blade 23 in the sheet conveying direction to prevent the rotated pressing guide member 30 from interfering with the folding blade 23. As a result, the rotating shaft 31 must also be disposed at a position away from the pair of folding rollers 22. In this regard, in the present embodiment, as described above, the rotating shaft 31 is configured to be disposed between the nip line L1 and the rotation axis line L2 in the sheet conveying direction, so that the position where the pressing portion 30c presses the sheet being switched back and conveyed can be brought closer to the nip portion 22c without unnecessarily lengthening the length of the rotating portion 30a.

[0063] Here, in addition to using different diameter rollers having first roller surfaces 22a2, 22b2 and second roller surfaces 22a3, 22b3 with different diameters as in this embodiment, it is also possible to use a pair of rollers with a constant roller diameter, but in that case, the length of the rotating part 30a needs to be shorter than the shortest distance to the outer periphery of the folding roller closer to the rotating axis.

[0064] 13, the pressing guide member 30 of this embodiment has a shape in which the guide portion 30b is located inside the rotation trajectory L3 of the rotating portion 30a and does not protrude outside the area. This prevents the guide portion 30b from interfering with the folding roller pair 22 even when the rotating portion 30a, which is configured to be long as described above, is rotated.

[0065] When the sheet that has been folded the first time as described above is conveyed in a switchback manner, it is returned to the sheet stacking tray 21 while being guided by the pressing guide member 30. After the sheet abuts against the regulating stopper 26 and the switchback conveyance is completed, the pressing guide member 30 is returned to the retracted position. At this time, the rotating portion 30a, which serves as the second guide surface of the pressing guide member 30, moves the sheet stacking tray 21 to a reverse conveyance guide position that protrudes slightly toward the sheet conveyance path side from the guide surface 21a so as to guide the sheet S conveyed in the reverse direction (see FIG. 8(b)).

[0066] After the pressing guide member 30 moves to the reverse conveying guide position, the regulating stopper 26 is raised to reversely convey the sheet so that the second folding position faces the folding blade 23. At this time, the sheet S is guided by the rotating portion 30a of the pressing guide member 30, and is conveyed without getting caught in the notches for attaching the pressing guide member formed in the guide surface 21a (see FIG. 9(a)).

[0067] <Blade guide member> After the second folding position of the sheet conveyed in the switchback manner as described above moves to a position facing the folding blade 23, the pressing guide member 30 is moved to the retracted position, and the folding blade 23 is operated to perform the second folding operation. At this time, the blade guide member 40 provided above the folding blade 23 is configured to guide the folded end S2 of the sheet (see FIG. 10(b)).

[0068] Next, the configuration and operation of the blade guide member 40 will be specifically described with reference to Figures 15 to 19. Note that Figure 15 is an explanatory diagram of the rotation of the blade guide member 40, and Figures 16 to 19 are diagrams showing the operation of the folding blade 23 and the blade guide member 40 when performing a second folding process on the sheet.

[0069] (Configuration of Blade Guide Member) When performing a second folding process on the sheet S, the blade guide member 40 moves in the protruding direction of the folding blade 23 to guide the sheet end on the crease side formed by the first folding process relative to the folding blade 23, i.e., the folded end S2 of the sheet, in the protruding direction to the nip portion 22c of the pair of folding rollers 22. For this purpose, as shown in FIG. 15, the blade guide member 40 has a contact portion 40a that contacts the rear end of the sheet, and a fitting hole portion 40b having a partial cutout is formed at one end of the contact portion 40a, and this fitting hole portion 40b is rotatably fitted to a shaft portion 40f formed in the base portion 40e. In addition, an arm portion 40c is integrally provided at the other end of the contact portion 40a, and an engagement protrusion portion 40d is formed at the end of the arm portion 40c. The engagement protrusion portion 40d is slidably engaged with a long hole 50 formed in the frame of the sheet processing device B. The slot 50 is formed in the vicinity of the upper portion of the blade carrier 24 and substantially parallel to the guide surface 21 a of the sheet stacking tray 21 .

[0070] The base portion 40e is attached to the blade carrier 24 so as to be slidable in a direction parallel to the movement direction of the blade carrier 24. A tension spring 51 is attached between a locking portion 40e1 formed on the base portion 40e and a locking portion 24a formed on the blade carrier 24.

[0071] The blade carrier 24 is provided with a pressing protrusion 24b capable of contacting and pressing the base portion 40e. The pressing protrusion 24b is provided rotatably on the blade carrier 24, and is biased in the counterclockwise direction in FIG. 15 by a coil spring 52 attached to a rotation shaft. As a result, when the blade carrier 24 moves in the blade protruding direction, the pressing protrusion 24b contacts the base portion 40e and presses the base portion 40e, and the blade guide member 40 moves integrally with the blade carrier 24. The coil spring 52 provided on the pressing protrusion 24b acts as a so-called torque limiter, and when a clockwise force of a predetermined value or more is applied to the pressing protrusion 24b, it rotates clockwise.

[0072] (Angle change of the contact part relative to the moving direction of the folding blade) In the above configuration, as shown in FIG. 15(a), when the blade carrier 24 is in the home position, the blade guide member 40 is pulled by the tension spring 51 and is in a position where the abutment portion 40a abuts against the rotation shaft 31 which serves as the rotation fulcrum of the pressing guide member 30. This state is the home position of the blade guide member 40. At this time, the abutment portion 40a stands up so as to be substantially flush with the guide surface 21a. When the blade carrier 24 moves from the home position in the blade protruding direction, the blade guide member 40 is pressed by the pressing protrusion portion 24b and moves together with the blade carrier 24, and moves until the abutment portion 40e2 formed in an upright position at the rear end of the base portion 40e abuts against the rotation shaft 31, as shown in FIG. 15(b).

[0073] As described above, when the blade guide member 40 moves in the blade protruding direction, the engaging protrusion 40d slides downward while being guided by the long hole 50, and the abutment portion 40a rotates around the shaft portion 40f. The shaft portion 40f is provided at one end of the abutment portion 40a closer to the folding blade 23. This one end refers to the area between the center of the abutment portion 40a and the end closer to the folding blade 23. In other words, the shaft portion 40f is provided in any area closer to the folding blade 23 than the center of the abutment portion 40a. Therefore, when the blade guide member 40 is in the home position as shown in FIG. 15(a), the abutment portion 40a is at an angle of approximately right angles to the moving direction of the blade carrier 24, i.e., the moving direction of the folding blade 23, and is in an upright state. 15(b), as the blade carrier 24 moves in the direction in which the folding blade 23 is protruding, the other end of the abutment part 40a moves closer to the movement path of the shaft part 40f which is the center of rotation, i.e., it rotates so as to fall toward the upstream side in the protruding direction of the folding blade 23, and the angle of the abutment part 40a with respect to the moving direction of the blade carrier 24 changes to an acute angle (the angle on the upstream side in the protruding direction becomes smaller) as the blade carrier 24 moves. As described above, one end of the abutment part 40a is configured to be rotatable about the shaft part, and the end of the arm part 40c provided by extending the other end of the abutment part 40a is configured to be slidable along the long hole 50, so that the blade guide member 40 can change its angle with respect to the moving direction in conjunction with the movement of the blade guide member 40 without providing a special driving means.

[0074] 15(a), a protrusion 40f1 is formed on the shaft portion 40f which serves as the rotation axis of the abutting portion 40a. On the other hand, a notch formed in the fitting hole portion 40b which fits with the shaft portion 40f is formed wider than the width of the protrusion 40f1, and the blade guide member 40 is rotatable within the range of the notch.

[0075] In the above configuration, when the blade carrier 24 moves to the home position, the base portion 40e is pulled by the tension spring 51, and at this time, the cutout surface of the fitting hole portion 40b abuts against the protrusion 40f1, restricting further rotation of the abutment portion 40a. Therefore, with the abutment portion 40a abutting against the rotation shaft 31, further movement of the blade guide member 40 is restricted, and the abutment portion 40a maintains an upright state at the home position.

[0076] In addition, in the blade guide member 40 of this embodiment, the contact portion 40a and the arm portion 40c are formed as linear members when viewed in cross section, and the arm portion 40c is formed at a predetermined angle with respect to the contact portion 40a. As a result, even if the contact portion 40a is configured to be substantially flush with the guide surface 21a when the blade guide member 40 is in the home position, the end portion of the arm portion 40c on the side where the engaging protrusion 40d is provided is located at a position farther away from the guide surface 21a on the side opposite to the side where the folding roller pair 22 is located. In other words, it is located at a position on the side of the guide surface 21a in the direction in which the folding blade 23 is returned to the home position from the nip portion 22c side. Therefore, the long hole 50 with which the engaging protrusion 40d engages can be located at a position farther away from the guide surface 21a on the side opposite to the side where the folding roller pair 22 is located, and can be located at a position that does not interfere with the guide surface 21a. Therefore, when the blade guide member 40 is in the home position, the contact portion 40a can be configured to function as a guide portion for the sheet transported on the sheet stacking tray 21.

[0077] (Operation of folding blade and blade guide member) Next, the operation of the blade guide member 40 when the folding blade 23 is operated to perform a second folding operation on the sheet will be described with reference to FIGS.

[0078] 16(a) shows a state in which the blade carrier 24 is in the home position, and at this time, the blade guide member 40 is also in the home position. In the following description, the direction in which the blade carrier 24 protrudes the folding blade 23 from the home position into the nip portion 22c of the pair of folding rollers 22 is referred to as the "protruding direction," and the direction in which the blade carrier 24 returns the folding blade 23 from the nip portion 22c side to the home position is referred to as the "returning direction."

[0079] When the blade 23 is in the home position, the tip of the folding blade 23 is substantially flush with the guide surface 21a or is located on the return direction side of the guide surface 21a (first position) and is separated from the sheet S on the sheet stacking tray 21. Therefore, the sheet guided by the guide surface 21a and transported to the sheet stacking tray 21 is not caught by the tip of the blade. Even if the tip of the folding blade 23 protrudes toward the folding roller 22 side from the guide surface 21a, if the sheet transported to the sheet stacking tray 21 by another guide member is not caught by the tip of the blade, it can be said that the tip of the blade is retracted from the sheet transport path, and this state may be the first position. When the blade guide member 40 is in the home position, the abutment portion 40a of the blade guide member 40 is in a position abutting the rotation shaft 31. At this time, the pressing protrusion 24b is separated from the base portion 40e.

[0080] Next, in order to protrude the folding blade 23, the cam drive motor is driven to rotate the cam member 25 and move the blade carrier 24 in the protruding direction. Then, the pressing protrusion 24b comes into contact with the base portion 40e, and the blade guide member 40 moves in the protruding direction together with the blade carrier 24 and the folding blade 23 (FIG. 16(b)). At this time, the tip of the folding blade 23 is configured to protrude in the protruding direction beyond the tip of the blade guide member 40.

[0081] When the blade carrier 24 moves further in the protruding direction, the tip of the folding blade protrudes a predetermined amount, and as shown in Fig. 17(a), the first folding process is performed, the second folding position faces the folding blade 23, and the tip of the folding blade 23 abuts against the sheet S stopped in the sheet stacking tray 21 (second position). At this time, as described above, since the tip of the folding blade 23 protrudes in the protruding direction further than the blade guide member 40, the folding blade 23 abuts against the folding position of the sheet S before the blade guide member 40. Therefore, due to the protrusion of the folding blade 23, the tip of the folding blade facing the folding position of the sheet accurately abuts without being deviated from the folding position of the sheet, and the folding process is performed at the correct folding position.

[0082] Furthermore, the tip of the folding blade does not necessarily have to protrude relative to the blade guide member 40, but as long as it is in the same position as the blade guide member 40 in the protruding direction, misalignment when the blade tip abuts the folding position of the sheet can be suppressed.

[0083] When the blade carrier 24 moves in the protruding direction in the above state, the folding blade 23 protrudes the second folding position of the sheet S toward the nip portion 22c of the pair of folding rollers 22. At the same time, the contact portion 40a of the blade guide member 40 contacts the folded end portion S2 of the sheet that has been folded the first time, and guides the folded end portion S2 so as to push it toward the nip portion 22c (FIG. 17(b)).

[0084] As described above, the blade guide member 40 guides the folded end S2 of the sheet to the nip portion 22c, so that the folded end S2 of the sheet heads toward the nip portion 22c without turning over. In addition, when the blade guide member 40 approaches the nip portion 22c, there is a risk that the protruding blade guide member 40 may interfere with the outer periphery of the folding rollers 22a and 22b. At this time, as described above, the blade guide member 40 of this embodiment moves in the protruding direction, and the angle of the abutting portion 40a with respect to the protruding direction changes to an acute angle (changing from the state of FIG. 17(a) to the state of FIG. 17(b)). Therefore, the abutting portion 40a can enter closer to the nip portion 22c, and the folded end S2 of the sheet can be reliably guided to the nip portion.

[0085] When the blade carrier 24 further moves in the protruding direction and the abutment portion 40e2 abuts against the rotating shaft 31 as shown in FIG. 17B, the blade guide member 40 is restricted from moving further in the protruding direction. When the blade guide member 40 moves to the furthest position in the protruding direction, the tip of the blade guide member 40 (the end on the folding roller pair 22 side in the protruding direction) protrudes toward the nip portion 22c from the tangent line (of the two folding rollers 22a and 22b) connecting the outer periphery of the folding roller 22a and the folding roller 22b on the sheet stacking tray 21 side. On the other hand, when the blade carrier 24 is pushed out in the protruding direction by the rotation of the cam member 25, as shown in FIG. 18A, the pressing protrusion 24b rotates clockwise against the biasing force of the coil spring 52 because a certain or more force is applied to the coil spring 52, and the pressing protrusion 24b slips under the lower part of the base portion 40e. As a result, the pressing protrusion 24b no longer presses the blade guide member 40, and the blade guide member 40 remains stationary, and only the folding blade 23 moves in the protruding direction to a position (third position) where the blade tip protrudes to the maximum and protrudes the sheet S into the nip portion 22c. At this time, the tip of the folding blade 23 protrudes farther than the tip of the abutting portion 40a of the blade guide member 40. That is, the distance from the blade tip to the abutting portion tip in the third position is greater than the distance from the blade tip to the abutting portion tip in the second position. As a result, the sheet is reliably drawn into the nip portion 22c of the pair of folding rollers 22 rotating in a state where it is folded at the second folding position, and the sheet tip S1 is also drawn into the nip portion 22c to be folded in three.

[0086] When the folding blade 23 is protruding the sheet, that is, when the tip of the folding blade is moving from the second position to the third position, if a large load is applied to the blade guide member 40 in the return direction, for example, when folding a plurality of sheets stacked together and the sheets have high rigidity, a large load is applied to the blade guide member 40 during folding. In this case, when a certain load or more is applied, the blade guide member 40 can move in the return direction relative to the folding blade 23 against the frictional force with the pressing protrusion 24b that is in pressure contact with the bottom surface of the base portion 40e by the biasing force of the coil spring 52. This prevents the blade guide member 40 from being damaged when a large load is applied to the blade guide member 40 during folding of the sheet.

[0087] When the cam member 25 rotates further after the tip of the folding blade reaches the third position, the blade carrier 24 moves in the return direction together with the folding blade 23 (FIG. 18(b)). At this time, as described above, the pressing protrusion 24b is in pressure contact with the base portion 40e of the blade guide member 40 by the biasing force of the coil spring 52, so that the blade guide member 40 also moves integrally with the blade carrier 24, i.e., simultaneously with the folding blade 23, in the return direction due to the frictional force between the pressing protrusion 24b and the bottom surface of the base portion 40e.

[0088] When the cam member 25 further rotates and the blade carrier 24 moves in the return direction, the abutment portion 40a of the blade guide member 40 abuts against the rotating shaft 31, and the blade guide member 40 returns to the home position. Further movement of the blade guide member 40 in the return direction is restricted (FIG. 19(a)). When the cam member 25 further rotates, the blade guide member 40 does not move, and only the folding blade 23 moves in the return direction and returns to the home position (FIG. 19(b)).

[0089] As described above, when the blade carrier 24 moves in the return direction, the folding blade 23 and the blade guide member 40 simultaneously move in the return direction, and the blade guide member 40 returns to the home position before the blade carrier 24 and the folding blade 23 return to their home positions. That is, the blade guide member 40 retreats from the sheet drawn in by the folding roller pair 22 and the discharge roller 17b earlier than the folding blade 23. Therefore, the transport load of the sheet S drawn in by the discharge roller 17b etc., which is caused by the blade guide member 40, is reduced.

[0090] (Arrangement relationship between the blade guide member and the pressure guide member) In this embodiment, as shown in FIG. 4, which is a schematic plan view of the folding device F, two blade guide members 40 are arranged at predetermined positions in the sheet width direction. The folding blade 23 in this embodiment has six protruding tips 23a formed at approximately equal intervals in the sheet width direction on the protruding side. The protruding tips 23a protrude the sheet, so that the sheet is protruded into the nip portion 22c of the folding roller pair 22 and folding processing is performed. The blade guide member 40 is arranged above the protruding tip 23a1 of the six protruding tips 23a, that is, on the upstream side in the carry-in direction of the sheet carried into the sheet stacking tray 21. Therefore, the folding end S2 of the sheet S protruded by the folding blade 23 is guided by the blade guide members 40 on both sides in the width direction.

[0091] In order to guide the folded end S2 of the sheet to the nip portion 22c, it is desirable to place the blade guide member 40 above all of the six thrust tips 23a (23a1), but placing it at all of them would increase the number of parts. In contrast, in this embodiment, the blade guide member 40 is placed at the positions of the two thrust tips 23a1 formed on both ends in the sheet width direction as described above, so the number of parts can be reduced. Furthermore, the folded end S2 of the sheet pushed out by the folding blade 23 during the second folding process is more likely to curl up near the end than the center in the sheet width direction, so by guiding this portion toward the nip portion with the blade guide member 40, the curling can be effectively prevented.

[0092] The two blade guide members 40 are disposed above the pushing tip 23a1 formed slightly toward the center rather than at both ends in the sheet width direction of the minimum width sheet that can be conveyed to the sheet stacking tray 21. This is because, when pushing out a sheet with the pushing tip 23a, it is more effective to push the sheet slightly toward the center rather than at the ends in the sheet width direction, and the blade guide members 40 are disposed in accordance with the position of the pushing tip 23a1.

[0093] With respect to the position of the blade guide member 40, the pressing guide member 30 of this embodiment is disposed outside the two blade guide members 40 in the sheet width direction. Specifically, the two pressing guide members 30 are disposed at intervals substantially equal to the width of the smallest size sheet that can be processed by the folding processing device F, and are disposed at positions where they can press and guide both ends of the sheet width direction when folding the smallest size sheet. In this embodiment, in addition to the two pressing guide members 30 capable of pressing and guiding both ends of the sheet, another pressing guide member 30 capable of pressing and guiding the center of the sheet width direction is provided, so that a total of three pressing guide members 30 are provided. More specifically, the smallest size sheet that can be processed by the folding processing device F in this embodiment is A4, and the width of a typical A4 size sheet in the short side direction is 210 mm. The two pressing guide members 30 capable of pressing and guiding both ends of the sheet in the width direction are formed to have a length in the sheet width direction of 18 mm, and the length of a straight line connecting the outer ends of each of the two pressing guide members 30 is 226 mm, which is longer than the width of an A4 size sheet, and the width direction ends of an A4 size sheet extend 10 mm on each side to a part close to the center in the width direction of the face of the pressing guide members 30. The maximum size of a sheet that can be processed by the folding device F is A3, and the width in the short direction of a typical A3 size sheet is 297 mm. By setting the length of a straight line connecting the outer ends of each of the two pressing guide members 30 capable of pressing and guiding both ends of the sheet in the width direction to be longer than the width of the minimum size sheet, it is possible to provide a guide effect even for the ends of the maximum size sheet.

[0094] When the sheet that has undergone the first folding process is fed back and the pressing guide member 30 presses the folded end S2 of the sheet to guide it back to the sheet stacking tray 21 as described above, pressing and guiding both ends in the sheet width direction is effective in preventing curling. For this reason, the two pressing guide members 30 are disposed on the outer side in the sheet width direction than the blade guide member 40. In this embodiment, the pressing guide members 30 disposed on both sides in the sheet width direction are disposed at a distance substantially equal to the width of the minimum size sheet, and the blade guide member 40 is disposed further inward with a distance shorter than the width of the minimum size sheet.

[0095] In this embodiment, the pushing tip 23a2 is disposed on the outside of each pressing guide member 30. The pushing tip 23a2 is intended to prevent wrinkles from occurring in the sheet when a large size sheet is pushed in the sheet width direction, and is disposed inside both ends of the maximum size sheet (it is not necessary to provide it in a device in which the sheets to be handled are limited to the above-mentioned minimum size). In other words, it is desirable to arrange the pressing guide member 30 and the blade guide member 40 according to the minimum size sheet, but the pushing tip 23a2 may be disposed separately on the outside of the pressing guide member 30 as necessary. In other words, the blade guide member 40 is disposed inside the two pressing guide members 30 in the sheet width direction, and the pushing tip 23a1 is disposed corresponding to the position of the blade guide member 40, and the pushing tip 23a2 may be disposed outside the two pressing guide members 30 according to the sheet size to be handled.

[0096] Furthermore, when there is a large difference between the minimum size and the maximum size that the device can handle, a blade guide member 40, a thrust tip 23a1 provided with the blade guide member 40, and two pressing guide members 30 corresponding to the minimum size, and a blade guide member 40, a thrust tip 23a2 provided with the blade guide member 40, and two pressing guide members 30 corresponding to the maximum size may be provided. Note that, although this embodiment has shown an aspect in which two thrust tips 23a1 provided with the blade guide member 40 are provided on either side of the center of the sheet S, a configuration with one thrust tip 23a1 and one blade guide member 40 may also be used.

[0097] In this embodiment, the pressing guide member 30 is disposed between the thrusting tip portion 23a1 and the thrusting tip portion 23a2 so as not to interfere with the thrusting tip portions 23a1 and 23a2 when the pressing guide member 30 moves to the guide position. Therefore, each member can be disposed in a space-saving manner.

[0098] <Drive control> Next, the control configuration of the drive system when folding a sheet will be described. As shown in the block diagram of Fig. 20, the control unit 60 controls the drive of a folding roller motor 61 that drives and rotates the folding roller pair 22, a discharge roller motor 62 that drives and rotates the discharge roller 17b, and a regulating stopper motor 63 that operates the sheet lifting mechanism 27 to lift and lower the regulating stopper 26, in accordance with the procedures of the flowcharts shown in Fig. 21 and Fig. 22. Similarly, the control unit 60 also controls the drive of a cam motor 64 that drives a cam member 25 to operate the blade carrier 24, and a pressing guide motor 33 that rotates the pressing guide member 30.

[0099] Figures 21 and 22 are flowcharts showing the drive control procedure when a folding process is performed from a state in which a sheet S is transported to the sheet stacking tray 21, the leading edge of the sheet hits a regulating stopper 26 stopped at a predetermined position, and the first folding position is in a position opposite the folding blade 23.

[0100] When the folding process is performed, the cam motor 64 is driven to move the blade carrier 24 in the protruding direction, and the folding blade 23 abuts against the first folding position of the sheet S and protrudes into the nip portion 22c (S1). At the same time, the folding roller motor 61 and the discharge roller motor 62 are driven to drive the folding roller pair 22 and the discharge roller 17b in the forward direction (S2). Each of the motors uses a pulse motor, and when the motor is driven, the number of drive pulses is counted.

[0101] When the folding blade 23 protrudes a predetermined amount to push the first fold of the sheet S to the nip portion 22c of the pair of folding rollers 22 by rotation of the cam member 25, the direction of travel is reversed and the blade moves in the return direction to the home position (S3).

[0102] The sheet S protruded into the nip portion 22c of the pair of folding rollers 22 by the protrusion of the folding blade 23 is folded while being sandwiched and conveyed by the pair of folding rollers 22, and is conveyed by the discharge roller 17b which constitutes the sheet conveying means together with the pair of folding rollers 22. When the sheet is sandwiched and conveyed by the discharge roller 17b (S4), the folding roller motor 61 stops when the second roller surfaces 22a3 and 22b3 of the folding rollers 22a and 22b face each other (S4, S5). As a result, the pair of folding rollers 22 no longer nip the sheet, and the sheet is conveyed by the discharge roller 17b. At this time, the sheet is conveyed by the discharge roller 17b while being guided by the second roller surfaces 22a3 and 22b3 which have a small coefficient of friction. In this embodiment, whether the sheet has been transported to the discharge roller 17b and whether the second roller surfaces 22a3, 22b3 of the folding roller pair 22 have faced each other is determined by counting the pulses of the motor, but other configurations may also be used, for example, to detect the sheet S using a sensor and control the drive of the motor according to the detection result.

[0103] Then, when the position of the folded end S2 of the conveyed sheet S reaches within a predetermined area (S7), the driving of the discharge roller motor 62 is stopped to stop the sheet conveyance (S8). This predetermined area is an area between the folded end S2 of the sheet and the rotation trajectory L3 of the pressing guide member 30 and the guide surface 21a of the sheet stacking tray 21 (see FIG. 14(a)). By stopping the sheet so that the folded end S2 is within the area, when the pressing guide member 30 is rotated, the pressing portion 30c can reliably press the sheet S in the switchback conveying direction (see FIG. 14(b)), and further the folded end S2 conveyed in the switchback can be guided by the guide portion 30b (see FIG. 14(c)).

[0104] After the folded end S2 of the sheet S is stopped within the area, the pressing guide motor 33 is driven to rotate the pressing guide member 30 so that the guide portion 30b of the pressing guide member 30 can guide the sheet S being switched back and transported (the position shown in FIG. 14(c)) (S9). In addition, together with the rotation of the pressing guide member 30, the regulating stopper motor 63 is driven to move the regulating stopper 26 to a position where it can accept the sheet S being switched back and transported.

[0105] After the pressing guide member 30 rotates as described above, the discharge roller motor 62 and the folding roller motor 61 are driven in the reverse direction (S10). This causes the discharge roller 17b and the pair of folding rollers 22 to rotate in the reverse direction, and the sheet S is conveyed in a switchback manner. At this time, since the sheet is guided by the pressing guide member 30 as described above, the sheet is conveyed in a switchback manner in the direction in which the regulating stopper 26 of the sheet stacking tray 21 is disposed, without causing a conveyance failure.

[0106] The discharge roller motor 62 and the folding roller motor 61 are driven to carry the sheet S in a switchback manner, and when the sheet S that has passed through the nip portion 22c of the pair of folding rollers 22 falls until it abuts against the regulating stopper 26 and the switchback transport is completed (S11), the driving of the discharge roller motor 62 and the folding roller motor 61 is stopped (S12). Here, the completion of the switchback transport of the sheet S may be determined by counting the number of drive pulses of the discharge roller motor 62 and the folding roller motor 61 and determining that the sheet S has been transported a predetermined amount.

[0107] Next, the pressing guide motor 33 is driven to return the pressing guide member 30 to the retracted position. At this time, the speed at which the pressing guide member 30 is returned from the guide position (see FIG. 14(c)) to the retracted position (see FIG. 14(a)) is set to a speed faster than that at which the pressing guide member 30 is moved from the retracted position to the guide position. When the pressing guide member 30 is moved from the retracted position to the guide position, the speed is reduced to press and change the orientation of the sheet S stopped for switchback transport, whereas when the pressing guide member 30 is moved from the guide position to the retracted position, the speed is returned quickly, thereby making it possible to advance the timing for executing the next operation.

[0108] Then, after the pressing guide member 30 is moved to the reverse conveying guide position (see FIG. 9(a)) (S13), the regulating stopper motor 63 is driven to move the second folding position of the sheet S to a position facing the folding blade 23 (S14). In this state, the cam motor 64, the folding roller motor 61, and the discharge roller motor 62 are driven to execute the second folding operation (S15 to S17).

[0109] In this embodiment, a motor is provided to drive each member individually, but it is also possible to use a common motor and drive each member by switching the drive using a clutch or the like.

[0110] <Other embodiments> In the above-described embodiment, when the folding blade 23 and the blade guide member 40 are moved relative to each other, the engaging protrusion 40d of the blade guide member 40 slides through the long hole 50 to change the angle of the abutting portion 40a with respect to the base portion 40e. However, the angle of the abutting portion 40a with respect to the base portion 40e may be fixed and not changed without providing the link mechanism. Even in this case, the folding blade 23 is configured to be movable relative to the blade guide member 40, and the folding blade 23 is protruded even after the movement of the blade guide member 40 stops during protrusion to protrude the sheet into the nip portion 22c, so that the sheet can be reliably protruded into the nip portion 22c without interfering with the blade guide member 40 and the folding roller pair 22. Furthermore, the configuration can be simplified by not providing an angle changing mechanism.

[0111] In the above-described embodiment, the folding rollers 22a, 22b are configured as rollers having a first roller surface 22a2, 22b2 with a circular outer circumference having a constant outer diameter, and a second roller surface 22a3, 22b3 with a smaller outer diameter. However, the folding rollers 22a, 22b may be configured as rollers having a constant outer diameter, such as circular rubber rollers. In this case, when the sheet passes through the pair of folding rollers, the sheet is always sandwiched in the nip portion of the pair of folding rollers, so that the conveyance amount of the sheet can be managed by the rotation of the pair of folding rollers. Therefore, when the folded end of the sheet is stopped at a predetermined position (see FIG. 7(a)), it can be controlled by the drive amount of the folding rollers.

[0112] In the above-described embodiment, an example has been shown in which the folding blade 23 and the blade guide member 40 start moving in the return direction simultaneously when the tip of the folding blade is in the third position. However, for example, the folding blade 23 and the blade guide member 40 may be configured to be operated by different drive systems, and the folding blade 23 may start moving in the return direction first, followed by the blade guide member 40.

[0113] Even when the tip of the folding blade protrudes to the third position and the folded portion of the sheet is nipped by the pair of folding rollers 22, the folded end S2 is not yet nipped in nip portion 22c (see FIG. 18(a)) and is nipped later. Even in this case, by returning the blade guide member 40 slower than the folding blade 23 as described above, even if the folding blade 23 starts to move in the return direction, the folded end S2 is guided by the blade guide member 40 and is reliably drawn into the nip portion 22c.

[0114] In the above-described embodiment, an example was shown in which the amount of sheet transport and the amount of rotation of the pressing guide member 30 were controlled by counting the number of motor pulses. However, other than the motor pulses, for example, a photosensor that detects the sheet or a photosensor that detects the pressing guide member 30 may be provided, and the sensor may detect that the sheet has been transported to a predetermined position or that the pressing guide member 30 has been rotated to a predetermined angle to control the sheet transport or the rotation of the pressing guide member.

[0115] In the above-described embodiment, the regulating stopper 26 for abutting and regulating the leading edge of the conveyed sheet in the conveying direction is disposed at the lower end of the sheet stacking tray 21, and the regulating stopper 26 is provided so as to be movable up and down along the sheet stacking tray 21 by the sheet lifting mechanism 27. In another embodiment, a pair of rollers for conveying the sheet to the upstream side or downstream side in the sheet conveying direction, sandwiching the folding blade 23 and the folding roller pair 22 of the sheet stacking tray 21, may be disposed. In that case, the sheet S that has been subjected to the first folding process can be returned to either the upstream side or the downstream side in the sheet conveying direction, sandwiching the folding blade 23 and the folding roller pair 22 of the sheet stacking tray 21, when being switched back and conveyed.

[0116] <Modification> 23 to 29 show modified examples of the blade guide member 40 and the blade carrier 24 (blade guide member 140 and blade carrier 124). The function of the blade guide member 140 is the same as in the above-mentioned embodiment, and the same reference numerals are used to designate the same members as in the above-mentioned embodiment, and the description thereof will be omitted. FIG. 23 is a perspective view showing the state in which the blade guide member 140 has moved in the protruding direction. Note that a pressing guide member 30 is provided on the right side of the blade guide member 140 in FIG. 23, but is not shown for convenience.

[0117] The blade guide member 140 is composed of an abutment portion 140a, an arm portion 140c, an engagement protrusion 140d, a locking portion 140e, a rotation fulcrum 140f, a pressed portion 140g, and a locking protrusion 140h. The abutment portion 140a is a member that abuts against and guides a sheet, and one end side of the abutment portion 140a is provided with a rotation fulcrum 140f, and the other end side is provided with the arm portion 140c, an engagement protrusion 140d that slidably engages with an elongated hole 50 formed in the frame of the sheet processing device B, and a locking portion 140e formed to stretch a tension spring 151 between the engagement protrusion 140d that slidably engages with an elongated hole 50 formed in the frame of the sheet processing device B, and a locking portion 124a formed in the frame of the sheet processing device B. The blade guide member 140 is biased in the upward direction of FIG. 25 by this tension spring 151. 25, a pressed portion 140g that is in contact with a pressing protrusion 124b1 (described later) is provided on the back side of the abutting portion 140a (upstream side in the protruding direction), and the pressed portion 140g is pushed in the protruding direction by the pressing protrusion 124b1, so that the abutting portion 140a rotates clockwise in Fig. 25 around the rotation fulcrum 140f. In other words, the abutting portion 140a is configured to be angle-changeable from an upright position that is substantially perpendicular to the folding blade 23a as shown in Fig. 25 to a position that is tilted toward the upstream side in the protruding direction around the rotation fulcrum 140f as shown in Fig. 26. The locking protrusion 140h bent from the rotation fulcrum 140f is a stopper for preventing the pressed portion 140g from coming off the pressing protrusion 124b1 when the pressing protrusion 124b1 is pressing the pressed portion 140g.

[0118] The blade carrier 124 holds the folding blade 23 and the slide rail 124c, and is configured to be movable together in the protruding direction and the return direction by the cam 25 (as in the above-mentioned embodiment). The slide rail 124c holds the pressing member 124b so that it can slide in the protruding direction and the return direction. The pressing member 124b has a pressing protrusion 124b1 formed at the downstream end of the pressing member 124b in the protruding direction, a locking portion 124b2 formed at the upstream end of the pressing member 124b in the protruding direction and locking with the spring 124e, and an abutting portion 124d formed between the pressing protrusion 124b1 and the locking portion 124b2.

[0119] Fig. 24 is a top view of the blade guide member 140 and the blade carrier 124. Fig. 24(a) shows the state in which the blade carrier 124 is in the home position (the thrusting tip 23a1 is in the first position), Fig. 24(b) shows the state in which the blade carrier 124 has moved a predetermined amount in the thrusting direction by the cam 25 (the thrusting tip 23a1 is in the second position), and Fig. 24(c) shows the state in which the blade carrier 124 has moved further in the thrusting direction and the thrusting tip 23a1 has protruded to the maximum and protruded the sheet S into the nip portion 22c (the thrusting tip 23a1 is in the third position).

[0120] A locking portion 124f to which one end of a spring 124e is attached is provided on the blade carrier 124. The other end of the spring 124e is attached to a locking portion 124b2 of the pressing member 124b, and the pressing member 124b is biased in the protruding direction (downward in FIG. 24) on the slide rail 124c by this spring 124e.

[0121] 25, the pressing member 124b and the slide rail 124c are provided with a protrusion 124b3 and a protrusion 124c1, respectively. The protrusion 124b3 and the protrusion 124c1 are engaged with each other, so that the movement of the pressing member 124b in the protruding direction is restricted even if the spring 124e biases the pressing member 124b in the protruding direction at the home position. When the blade carrier 124 moves in the protruding direction in this state, the slide rail 124c moves in the protruding direction, and the protrusion 124c1 provided on the slide rail 124c also moves in the protruding direction. As the protrusion 124c1 moves, the pressing member 124b biased by the spring 124e also moves in the protruding direction at the same time.

[0122] 25, the pressing member 124b moves in the protruding direction, causing the pressing protrusion 124b1 to press the pressed portion 140g of the blade guide member 140, and to move the abutting portion 140a of the blade guide member 140 in the protruding direction. At this time, the blade guide member 140 rotates clockwise around the rotation fulcrum 140f against the biasing force of the tension spring 151 while the engagement protrusion 140d slides downward through the long hole 50.

[0123] 26 (the thrust tip 23a1 is in the second position), the abutment portion 124d of the pressing member 124b abuts against the rotation shaft 31 of the pressing guide member 30, restricting the movement of the pressing member 124b in the thrust direction. This prevents the pressing member 124b from moving any further in the thrust direction even if the pressing member 124b is biased in the thrust direction by the spring 124e. At this position, the abutment portion 140a of the blade guide member 140 guides the sheet toward the folding roller pair 22, and the thrust tip 23a abuts against the sheet to thrust it toward the folding roller pair.

[0124] When the blade carrier 124 further moves in the protruding direction, the state shown in FIG. 27 is reached. In FIG. 27, the blade guide member 140 remains stopped at the position shown in FIG. 26, and only the blade carrier 124, the folding blade 23 (protruding tip 23a), and the slide rail 124c move in the protruding direction, and the protruding tip 23a1 protrudes to the maximum and moves to a position (third position) where the sheet S is protruded into the nip portion 22c. At this time, the protruding tip 23a1 of the folding blade 23 protrudes farther than the tip of the abutting portion 140a of the blade guide member 140. That is, the distance from the blade tip to the abutting tip at the third position is greater than the distance from the blade tip to the abutting tip at the second position. As a result, the sheet is reliably drawn into the nip portion 22c of the pair of folding rollers 22 rotating in a state where it is folded at the second folding position, and the sheet tip S1 is also drawn into the nip portion 22c to be folded in three.

[0125] After that, the blade carrier 124 moves in the return direction. At this time, the pressing member 124b is stopped at the position shown in FIG. 26. FIG. 28 shows the state where the thrust tip 23a1 has returned to the second position. Here, the protrusion 124c1 provided on the slide rail 124c engages with the protrusion 124b3 provided on the pressing member 124b. When the blade carrier 124 is further moved in the return direction in this state, the slide rail 124c and the pressing member 124b move in the return direction at the same time against the biasing force of the spring 124e. When the pressing member 124b moves in the return direction from the position shown in FIG. 28, the pressing protrusion 124b1 moves in a direction away from the pressed portion 140g of the blade guide member 140, and the blade guide member 140 changes its angle to the upright position shown in FIG. 29 due to the biasing force of the tension spring 151.

[0126] In addition, when the folding blade 23 is protruding the sheet, that is, when the protruding tip 23a1 is moving from the second position to the third position, if a large load is applied to the blade guide member 140 in the return direction, for example, when folding a plurality of sheets in a stacked state and the sheets have high rigidity, a large load is applied to the blade guide member 140 during folding. In this case, when a certain load or more is applied, the blade guide member 140 can move in the return direction relative to the folding blade 23 against the spring 124e. As described above, the blade guide member 140 is biased in the protruding direction by the spring 124e via the pressing member 124b, so that when a load equal to or greater than the biasing force of the spring 124e is applied to the blade guide member 140, the blade guide member 140 is configured to be movable in the return direction along the slide rail 124c. This prevents the blade guide member 140 from being damaged when a large load is applied to the blade guide member 140 during folding of the sheet.

[0127] 30 to 33 are diagrams illustrating a deflection guide 170 provided between the folding roller 22a and the guide surface 21a of the sheet stacking tray 21. The deflection guide 170 has a flexible guide member 170a (such as Mylar) that contacts the sheet S to guide the sheet S, and one end of the guide member 170a is fixed to a bracket 172. The bracket 172 has an engagement piece 171 that protrudes toward the folding roller 22a, and the engagement piece 171 is positioned by engaging with an engagement portion 22d (see FIG. 33) of the folding roller 22a. The engagement portion 22d of the folding roller 22a has a first roller surface 22a2 with a constant radius R1 centered on the rotation axis of the rotation shaft 22a1, and a second roller surface 22a3 whose distance from the rotation axis of the rotation shaft is smaller than the radius R1 of the first roller surface 22a2. When folding roller 22a rotates with engagement piece 171 engaged with engagement portion 22d, bracket 172 holding guide member 170a is configured to be rotatable about pivot shaft 173. The surface of engagement portion 22d with which engagement piece 171 engages is formed of a plastic resin material or the like having a small coefficient of friction.

[0128] In this embodiment, the guide member 170a is provided with a guide area capable of guiding the conveyed sheet S, and the lower end of the guide area in Fig. 30 is called the first end 170a1, and the upper end is called the second end 170a2. If the bracket 172 is also capable of guiding the sheet S, the sheet guide area of ​​the bracket 172 is also considered to be part of the guide member 170a, and the second end 170a2 is the upper end of the guide area of ​​the bracket 172.

[0129] In addition, in this embodiment, the space sandwiched between the first transport guide member 181 and the second transport guide member 182 that constitute the sheet transport path 20 is called the guide space 180, and the space sandwiched between the first loading guide member 184 and the second loading guide member 185 that form the sheet stacking tray 21 is called the storage space 183.

[0130] Fig. 30 shows a state in which the sheet S is transported from the guide space 180 toward the storage space 183 (this direction is called the first transport direction) with the engagement piece 171 engaged with the first roller surface 22a2 and the guide member 170a positioned at the first guide position. Fig. 31 shows a state in which the sheet S (in this figure, the sheet S that has been folded once) is transported from the storage space 183 toward the guide space 180 (this direction is called the second transport direction) with the engagement piece 171 engaged with the second roller surface 22a3 and the guide member 170a positioned at the second guide position.

[0131] Fig. 32(a) shows a state where the guide member 170a is positioned at the first guide position, and Fig. 32(b) shows a state where the guide member 170a is positioned at the second guide position. The dashed-dotted line 186 in the figure is a line (hereinafter referred to as the virtual line 186) connecting a transport guide end 181a, which is the downstream end of the first transport guide member 181 in the first transport direction, and a loading guide end 184a, which is the downstream end of the first loading guide member 184 in the second transport direction.

[0132] 32(a), when guide member 170a is located at the first guide position, first end 170a1 of guide member 170a is located on the opposite side of folding roller 22a (guide surface 21a side) from imaginary line 186 in the thickness direction of sheet S to be transported. Second end 170a2 is located on the folding roller 22a side from imaginary line 186 in the thickness direction of sheet S. This allows the leading end of sheet S (downstream end in the first transport direction) to be guided from guide space 180 to storage space 183 when sheet S is transported in the first transport direction as shown in FIGS. 30(a) and 30(b).

[0133] 32(b), when guide member 170a is located at the second guide position, first end 170a1 of guide member 170a is located closer to folding roller 22a in the thickness direction of sheet S being transported than imaginary line 186. Second end 170a2 is located on the opposite side of folding roller 22a (guide surface 21a side) in the thickness direction of sheet S than imaginary line 186. This allows the leading end of sheet S (downstream end in the second transport direction) to be guided from storage space 183 to guide space 180 when sheet S is transported in the second transport direction as shown in FIGS.

[0134] As shown in Fig. 33, a plurality of guide members 170a are provided in the width direction of sheet S. In this embodiment, two guide members 170a are arranged on both sides of the center of the sheet width inside the minimum size of the sheet width in the sheet width direction. The broken lines in Fig. 33 indicate folding rollers 22a and 22b, and engagement piece 171 is provided at a position corresponding to engagement portion 22d of folding roller 22a. Also, guide member 170a is arranged at a position corresponding to the two innermost thrusting tips 23a of the six thrusting tips 23a, 23a1, and 23a2.

[0135] The guide member 170a guides the sheet S not only when the sheet S is transported in the first transport direction and the second transport direction, but also when the folding blade 23 performs a protruding operation. As described above, Fig. 25 shows a state in which the folding position of the sheet S is positioned at a position facing the folding blade 23 when performing folding processing. In Fig. 25, the guide member 170a is positioned at the first guide position.

[0136] In this state, when the folding blade 23 is moved in the protruding direction, the position of the sheet S is stabilized between the guide member 170a and the abutting portion 140a of the blade guide member 140, so that it is possible to prevent the sheet from shifting in position during the folding process. As described above, since the guide member 170a is made of flexible Mylar or the like, when the sheet S abuts against it, the guide member 170a guides the sheet S in a state of being bent in the protruding direction.

[0137] When the pushing tip 23a1 of the folding blade 23 pushes the sheet S into the nip portion 22c of the folding roller pair 22 and the folding roller pair 22 is rotated a predetermined amount, the engagement piece 171 engages with the second roller surface 22a3 and the guide member 170a is positioned at the second guide position (see FIG. 28). This is because if the guide member 170a continues to bias the sheet S in the return direction even after the folded end S2 of the sheet S is folded into the nip portion 22c, the conveying load of the sheet S by the folding roller pair 22 becomes large, so when the folding position of the sheet S reaches the nip portion 22c of the folding roller pair 22 and the folding process by the folding roller pair 22 starts, it is desirable to move the guide member 170a to the second guide position and guide the sheet S toward the nip portion 22c.

[0138] From the above, when the sheet S is transported in the first transport direction (sheet transport for receiving the sheet S in the sheet stacking tray 21), the guide member 170a of the deflection guide 170 is positioned at the first guide position to guide the sheet S from the guide space 180 to the storage space 183, and when the sheet S is transported in the second transport direction (sheet transport for transporting the sheet S received in the sheet stacking tray 21 to the binding processing unit 17a, or sheet transport for bringing the second folding position of the sheet S facing the folding blade 23 to perform the second folding process after the first folding process is completed), the guide member 170a is positioned at the second guide position to guide the sheet S from the storage space 183 to the guide space 180.

[0139] In addition, when performing the folding process, the guide member 170a is positioned at the first guide position to guide the sheet S so that the folding position does not shift until the folding blade 23 pushes the sheet S into the nip portion 22c of the pair of folding rollers 22, and after the folding position of the sheet S reaches the nip portion 22c, the guide member 170a is positioned at the second guide position to guide the sheet S to the nip portion 22c while reducing the transport load.

[0140] In this embodiment, in order to move guide member 170a between the first guide position and the second guide position, engaging piece 171 is brought into contact with the peripheral surface (engaging portion 22d) of folding roller 22a having a different diameter to move guide member 170a, but it may be moved using another driving source. Also, while the embodiment shows a mode in which guide member 170a is disposed between folding roller 22a and guide surface 21a, it may be disposed between folding roller 22b and guide surface 21a, or may be disposed on both.

[0141] In the present embodiment, the first guide position of the guide member 170a during sheet conveyance and the first guide position of the guide member 170a during folding are the same, but they do not need to be exactly the same and can be changed as appropriate. It goes without saying that the second position can also be changed as appropriate.

[0142] In addition, in all of the above-described embodiments, the sheet S is folded twice to fold in three, but even in a single folding process (the first folding process for folding in three or the folding process for folding in two), if the above-described blade guide members 40 and 140 are provided, the sheet S can be appropriately guided during the folding process. [Explanation of symbols]

[0143] A … Image forming device B … Sheet processing device F … Folding device L1 …nip line L2 …Rotation axis L3 …Rotation trajectory S...Seat S1 ... Seat tip S2 … Folded end 20 …Sheet transport path 21 ... Sheet loading tray 21a … Guide surface 22 ... Folding roller pair 22a, 22b ... folding rollers 22a1, 22b1 … Rotating shaft 22a2, 22b2 … First roller surface 22a3, 22b3 … Second roller surface 22c...Nip section 23 … Folding blade 23a … thrust tip 24 ... Blade carrier 24a...Locking part 24b ... Pressing protrusion 24c...Campin 25 ... Cam member 25a …Rotary axis 25b ... Cam groove 26 ...Regulation stopper 27 ... Seat lift mechanism 27c...Transmission belt 28a, 28b ... Sheet side alignment members 30 ... Pressure guide member 30a … Rotating part 30b ... Guide section 30c ... Pressing part 31 ... Rotating shaft 32 ... Drive transmission member 33 ... Pressure guide motor 40...Blade guide member 40a...Abutment part 40b…Mating hole part 40c …Arm section 40d...Engagement protrusion 40e...Base part 40e1 ... Locking part 40e2 …Abutting section 40f...Shaft part 40f1…protrusion 50...long hole 51 ...Tension spring 52 ... coil spring 60 ... Control section 61 ... Folding roller motor 62 ... Discharge roller motor 63 ...Regulation stopper motor 64 ... Cam motor 124 ... Blade carrier 140 ... Blade guide member 170 ... Deflection guide

Claims

1. A sheet processing device performs a first folding process on a sheet, and then performs a second folding process at a position different from the crease formed by the first folding process, so that one end of the sheet folded by the first folding process is located inside the folded sheet, a conveying path having a guide surface for guiding a conveyed sheet; a pair of rotating bodies that rotate while nipping the sheet conveyed to the conveying path at a nip portion to draw in the sheet and perform a folding process; a protruding member having a tip portion that protrudes the sheet transported to the transport path toward the nip portion of the pair of rotating bodies, the protruding member being movable between a first position where the tip portion is retracted from the transport path, a second position where the tip portion protrudes a predetermined amount into the transport path, and a third position where the tip portion protrudes the sheet into the nip portion of the pair of rotating bodies; a push-out guide member having a guide portion that pushes out the one end of the sheet folded in the first folding process so as to approach the pair of rotating bodies when the push-out member pushes out the sheet into the nip portion during the second folding process; a moving means for moving the protruding member and the protruding guide member in a protruding direction toward the nip portion and in a return direction opposite thereto; Equipped with The sheet processing apparatus is characterized in that the moving means moves the protruding member and the protruding guide member relative to each other so that the distance from the tip portion to the guide portion at the third position is longer than the distance from the tip portion to the guide portion at the second position.

2. The sheet processing apparatus according to claim 1 , wherein the tip portion protrudes in the protruding direction beyond the guide portion at the second position.

3. The sheet processing apparatus according to claim 1 , wherein the leading end portion, at the first position, is at the same position in the protruding direction as the guide portion or at a position in the returning direction as the leading end portion.

4. 2 . The sheet processing apparatus according to claim 1 , wherein the moving means moves the push-out guide member in the return direction at the same time as starting to move the push-out member in the return direction.

5. 2 . The sheet processing apparatus according to claim 1 , wherein the moving means, when starting to move the push-out member in the return direction, starts to move the push-out guide member in the return direction later than the push-out member.

6. 2. The sheet processing apparatus according to claim 1, wherein when a load of a predetermined magnitude or more is applied to the extrusion guide member in the return direction while the extrusion member is between the second position and the third position, the moving means moves the extrusion guide member in the return direction relative to the extrusion member.

7. A sheet processing device performs a first folding process on a sheet, and then performs a second folding process at a position different from the crease formed by the first folding process, so that one end of the sheet folded by the first folding process is located inside the folded sheet, A support portion that supports the seat; a pair of folding rollers that rotate while holding the sheet supported by the support portion at a nip portion to draw in and fold the sheet; a protruding member that protrudes the sheet supported by the support portion in a protruding direction toward the nip portion; a push-out member that pushes out the one end of the sheet folded in the first folding process so as to approach the pair of folding rollers when the push-out member pushes out the sheet into the nip portion during the second folding process; a moving mechanism that moves both the protruding member and the pushing-out member in the protruding direction, stops the protruding member before the protruding member reaches the pair of folding rollers in the protruding direction, and further moves the protruding member in the protruding direction after the protruding member has stopped; A sheet processing apparatus comprising:

8. an image forming apparatus for forming an image on a sheet; a sheet processing device that performs folding processing on the sheet sent from the image forming device; having 8. An image forming system, comprising: the sheet processing apparatus according to claim 1.

Images