JP3824985B2 - Paper folding device, paper processing device, and image forming system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper folding device that performs folding processing on a sheet (recording medium) on which an image has been formed, a paper processing device that performs predetermined processing including folding processing on the paper by the paper folding device, and discharges the paper. The present invention also relates to an image forming system in which the sheet processing apparatus and an image forming apparatus such as a copying machine, a printer, and a printing machine are integrated or separated.
[0002]
[Prior art]
2. Description of the Related Art Post-processing devices that are disposed downstream of an image output device such as a copying machine or a printer and perform post-processing such as binding and punching on output recording paper (paper-recording medium) are widely known. In recent years, it has been proposed that the functions are multifunctional, and in addition to the conventional end face binding, the saddle stitching process and the middle folding process are also possible.
[0003]
Conventionally, in this type of sheet processing apparatus, as a folding means for saddle stitch binding, a binding portion of a sheet bundle bound at the center is pushed out by a folding plate in a direction substantially perpendicular to the paper surface of the sheet bundle, and folded including the sheet bundle. The sheet bundle is half-folded (middle-folded) by passing a pair of folding rollers provided in the moving direction of the plate. In such saddle stitching and middle folding, it is important that the folding position by the folding roller and the binding position are exactly the same. That is, if the folding position by the folding roller and the binding position are exactly the same, the appearance is good, and the spread is very good when the page is turned. Therefore, the coincidence between the folding position and the binding position is also a strong demand of the user.
[0004]
In response to such a demand, for example, an invention described in JP-A-10-279177 has been proposed. In the present invention, when a sheet bundle is passed through a pair of folding rollers to make a crease, the center position of the gap generated by the separation of the folding rollers always coincides with the common tangent position at the time of contact. The other folding roller is moved in the opposite direction following the movement of the roller. This movement is provided between a pair of swing arms each having the folding roller supported at one end and rotating with the other end serving as a rotation axis, and the one swing arm. In response to the rotation of the other swing arm, the other swing arm is rotated in the opposite direction by the same angle using a connecting means such as a gear. As a result, the pair of folding rollers pressurize while being displaced symmetrically with respect to the folding center with respect to the folding position of the sheet bundle, so that the folding position does not deviate when the sheet bundle passes through the folding roller pair. The positions can be matched.
[0005]
An invention disclosed in Japanese Patent Laid-Open No. 2000-143088 is also known. The present invention prevents sheet slippage due to relative movement between the outermost layer sheet and the inner layer sheet of the sheet bundle, and does not cause sheet damage such as wrinkles or tears, so as to obtain an orderly folded sheet bundle. The tip of the protruding plate that contacts the fold portion of the sheet bundle is moved by the drive means to the maximum insertion position that passes the pressure contact position of the folding roller, and the fold portion of the sheet bundle is pushed in. The folding roller keeps rotating until the leading end of the ejection plate reaches the maximum insertion position, and starts rotating when the leading end of the ejection plate reaches the maximum insertion position. .
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-279177
[Patent Document 2]
Japanese Patent Laid-Open No. 2000-143088
[Problems to be solved by the invention]
As described above, in the technique disclosed in Japanese Patent Laid-Open No. 10-279177, the folding position can be matched with the binding position without shifting the folding position when the sheet bundle passes through the pair of folding rollers. As means for rotating the other swing arm in the opposite direction in accordance with the rotation, a connecting means such as a gear is used between the rotation axes. In general, in order to perform strong folding on the sheet bundle, it is necessary to set the pressing force of the folding roller to a high pressing force accordingly. However, since there is a limit in terms of strength in displacing the folding roller using a connecting means such as a gear between the rotating shafts, the pressing force of the folding roller must be set relatively low. Therefore, there is a limit to the range in which folding can be performed. Such weakness of folding is not desirable for the user because the booklet that is saddle-stitched is likely to deteriorate in appearance or collapse on the stacking tray.
[0009]
In general, as the sheet bundle becomes thicker, the nip interval between the pair of folding rollers at the time of middle folding becomes wider, and it becomes difficult to hold and hold the folding plate accurately at the center of the nip interval. In addition, in this mechanism, when a half-folding operation is performed in the absence of paper, the vicinity of the nip of the pair of folding rollers and the folding plate may interfere with each other and an excessive force may be applied to the mechanism. In order to solve these problems, there is a method of limiting the maximum pushing position of the folding plate to just before the nip of the folding roller. For example, an image is formed around the folded portion in the center of the sheet, and the toner is on the sheet. In such a case, the frictional force between the paper on the outside and inside of the paper bundle may be lower than the frictional force between the folding roller and the paper. However, the sheet bundle may not be sufficiently caught in the nip of the pair of folding rollers, or the sheet in the stipple portion may be torn.
[0010]
On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 2000-143088, the leading end of the ejection plate moves to the maximum insertion position that passes through the pressure contact position of the folding roller and pushes in the fold portion of the sheet bundle. The rotation is stopped until the leading end of the plate reaches the maximum insertion position, and the rotation starts when the leading end of the protruding plate reaches the maximum insertion position. That is, the present invention sets the rotation start timing of the folding roller, and does not intend to apply even folding. For this reason, when the sheet bundle passes through the nip position of the folding roller, the folding roller is not rotating, and the influence of friction is not excluded, so that the folding roller is surely caught in the nip portion. It is hard to say that it is.
[0011]
The present invention has been made in view of the situation of the prior art as described above, and an object of the present invention is to securely bite a sheet bundle and fold it symmetrically and beautifully with respect to a folding position by a folding plate. It is an object of the present invention to provide a folding device, a paper processing device, and an image forming system that enable reliable half-folding and that can perform a smaller and high-quality saddle stitch binding process.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the first means is a paper folding apparatus that folds a paper by pressing the folding plate into a nip of a pair of folding rollers by bringing the folding plate into contact with the paper surface of the paper or the paper bundle. A pair of arms supported at one end in a freely swingable manner and elastically biased in directions close to each other at the other end, a folding roller rotatably supported by the one arm, and coaxial with the folding roller A guide roller provided, and a folding plate advancing / retreating guide disposed between the pair of guide rollers and performing advancing / retreating operation in conjunction with the advancing / retreating operation of the folding plate; The folding roller is supported by the arm so that the folding roller moves substantially symmetrically with respect to the surface extended in the direction.
[0013]
With this configuration, the folding roller moves symmetrically with respect to the advancing / retreating guide that moves in conjunction with the folding plate for defining the position of the crease and attaching the crease, so that an equal force is applied to the crease. , Accurate folding is possible.
[0014]
The second means is characterized by comprising restriction means for restricting the guide position and direction of the advance / retreat guide.
[0015]
With this configuration, the guide position and direction of the advancing / retreating guide are regulated, so that the advancing / retreating guide can move without deviating from a predetermined position, thereby maintaining the symmetry of the folding plate movement with high accuracy. it can.
[0016]
According to a third means, in the second means, the restricting means includes a guide groove formed in a length corresponding to a moving distance of the advance / retreat guide along a central longitudinal direction, and a guide pin inserted into the guide groove. And a pair of guide rollers provided in parallel with the axial direction of the pair of folding rollers and contacting both ends of the advance / retreat guide across the guide groove.
[0017]
In this way, the restricting means can be configured with a mechanically simple configuration of guide grooves, guide pins, and guide rollers.
[0018]
According to a fourth means, in the first means, when the front end of the folding plate is pushed to the vicinity of the nip of the pair of folding rollers, the contact of the guide roller of the advance / retreat guide is separated so that the nip of the folding roller is separated. A cam is formed on the contact surface.
[0019]
When the cam is formed in this way, the folding rollers can be separated symmetrically along the cam shape.
[0020]
According to a fourth means, in the fourth means, when the folding plate enters between the nips of the pair of folding rollers, at least the thickness of the entry portion of the folding plate into the nip portion is larger. The shape of the cam is set.
[0021]
This prevents interference between the tip of the folding plate and the nip portion of the folding roller, facilitates entry of the sheet bundle into the nip portion, and forms a beautiful crease without creases. it can.
[0022]
A sixth means is characterized in that, in the first means, the folding plate is provided integrally with the advance / retreat guide.
[0023]
When the folding plate is provided integrally with the advance / retreat guide, a reliable interlocking operation is possible, and the relative positions of both do not shift.
[0024]
The seventh means comprises a binding means for binding the central portion of the sheet bundle and the folding device according to any one of claims 1 to 5.
[0025]
If comprised in this way, it can be surely folded in two at a binding position, and a bookbinding of a beautiful crease will be attained.
[0026]
The eighth means is characterized in that the paper processing apparatus according to the sixth means and the image forming apparatus that forms a visible image on the paper are configured integrally or separately.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
1. 1. Mechanical Configuration 1.1 Overall Configuration FIG. 1 is a diagram showing a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus as a sheet processing apparatus according to an embodiment of the present invention. 2 shows an entire post-processing apparatus and a part of an image forming apparatus.
[0029]
In FIG. 1, the sheet post-processing apparatus PD is attached to the side of the image forming apparatus PR, and the recording medium discharged from the carry-out port 95 of the image forming apparatus PR, here, the sheet is loaded into the sheet post-processing apparatus PD. Guided to mouth 18. The sheet passes through a conveyance path A having post-processing means (in this embodiment, a punch unit 100 as a punching means) for post-processing one sheet, and then to the conveyance path B and the shift tray 202 which are led to the upper tray 201. The branching claw 15 and the branching claw 16 are configured to distribute to the conveyance path C that leads to the conveyance path D that leads to the conveyance path C that guides and the processing tray F that performs alignment and stapling (hereinafter also referred to as a staple processing tray).
[0030]
The sheet guided to the staple processing tray F through the conveyance paths A and D and aligned and stapled by the staple processing tray F is guided to the shift tray 202 by the branch guide plate 54 and the movable guide 55 which are deflection means. The sheet is arranged so as to be distributed to the conveyance path C, a processing tray G that performs folding or the like (hereinafter also referred to as a middle folding processing tray), and the sheet that is folded or the like in the middle folding processing tray G passes through the conveyance path H to the lower tray. 203. Further, a branching claw 17 is disposed in the conveyance path D, and is held in the state shown in the figure by a low load spring (not shown). After the trailing edge of the sheet passes through this, the conveyance rollers 9, 10 and the staple discharge roller 11, at least the transport roller 9 is reversed, and the prestack roller 8 is further reversed to guide the paper trailing edge to the paper storage portion E to be retained. When the next paper is transported, at least the transport roller 9 and the prestack The roller 8 is rotated forward so that the previous sheet can be conveyed while being overlapped with the next sheet. By repeating this operation, it is possible to convey two or more sheets in a superimposed manner.
[0031]
In the conveyance path A common to the upstream of the conveyance path B, the conveyance path C, and the conveyance path D, an inlet sensor 301 that detects a sheet received from the image forming apparatus, an inlet roller 1, a punch unit 100, and a punch downstream thereof. The waste hopper 101, the conveying roller 2, the branching claw 15 and the branching claw 16 are sequentially arranged. The branch claw 15 and the branch claw 16 are held in the state shown in FIG. 1 by a spring (not shown), and when the solenoid (not shown) is turned on, the branch claw 15 rotates upward and the branch claw 16 rotates downward. The paper is distributed to the conveyance path B, the conveyance path C, and the conveyance path D. Reference numeral 101a denotes a punch dust receiving port.
[0032]
When guiding the paper to the conveyance path B, the branching claw 15 is in the state of FIG. 1 and the solenoid is OFF. When guiding the paper to the conveyance path C, the branching claw 15 is turned on by turning on the solenoid from the state of FIG. When the paper is guided to the transport path D, the branch claw 16 is in the state of FIG. 1, the solenoid is OFF, and the branch claw 15 is in the state of FIG. By turning on the solenoid, the solenoid is turned upward.
[0033]
In this paper post-processing apparatus, punching (punching unit 100), paper alignment + edge binding (jogger fence 53, edge binding stapler S1), paper alignment + saddle stitching (jogger fence 53, saddle stitching stapler) is performed on the paper. Each process such as S2), paper sorting (shift tray 202), middle folding (folding plate 74, folding rollers 81, 82) can be performed.
[0034]
1.2 Shift Tray Unit The shift tray paper discharge unit I located at the most downstream portion of the sheet post-processing apparatus PD includes a shift paper discharge roller 6, a return roller 13, a paper surface detection sensor 330, a shift tray 202, The shift mechanism J shown in FIG. 2 and the shift tray lifting mechanism K shown in FIG. 2 is an enlarged perspective view of the main part showing details of the shift mechanism J, and FIG. 3 is an enlarged perspective view of the main part of the shift tray lifting mechanism K.
[0035]
1 and 3, reference numeral 13 denotes a sponge roller for contacting the paper discharged from the shift paper discharge roller 6 and aligning the rear end of the paper against the end fence 32 shown in FIG. The return roller 13 is rotated by the rotational force of the shift paper discharge roller 6. A tray lift limit switch 333 is provided in the vicinity of the return roller 13, and when the shift tray 202 is lifted to push up the return roller 13, the tray lift limit switch 333 is turned on and the tray lifting / lowering motor 168 is stopped. Thereby, overrun of the shift tray 202 is prevented. Further, as shown in FIG. 1, a paper surface detection sensor 330 is provided in the vicinity of the return roller 13 as paper surface position detecting means for detecting the paper surface position of the paper discharged on the shift tray 202 or the sheet bundle. Yes.
[0036]
Although not shown in detail in FIG. 1, the paper surface detection sensor 330 includes the paper surface detection lever 30 shown in FIG. 3, a paper surface detection sensor (for stippling) 330a, and a paper surface detection sensor (for non-stipple) 330b. Yes. The paper surface detection lever 30 is provided so as to be rotatable about the shaft portion of the lever, and includes a contact portion 30 a that contacts the upper surface of the rear end of the paper loaded on the shift tray 202 and a fan-shaped shielding portion 30 b. The paper surface detection sensor (for stippling) 330a located above is mainly used for staple discharge control, and the paper surface detection sensor (for non-stipple) 330b is mainly used for shift discharge control.
[0037]
In the present embodiment, the paper surface detection sensor (for stipple) 330a and the paper surface detection sensor (for non-stipple) 330b are turned on when blocked by the shielding portion 30b. Therefore, when the shift tray 202 is raised and the contact portion 30a of the paper surface detection lever 30 is rotated upward, the paper surface detection sensor (for stippling) 330a is turned off, and when further rotated, the paper surface detection sensor (for non-stipple) 330b is turned on. To do. When it is detected by the paper surface detection sensor (for stipple) 330 a and the paper surface detection sensor (for non-stipple) 330 b that the paper stacking amount has reached a predetermined height, the shift tray 202 is driven by the tray lifting / lowering motor 168 to a predetermined amount. Descend. Thereby, the paper surface position of the shift tray 202 is kept substantially constant.
[0038]
1.2.1 Lift Tray Lifting Mechanism The lifting mechanism for the shift tray 202 will be described in detail.
[0039]
As shown in FIG. 3, the shift tray 202 moves up and down when the drive shaft 21 is driven by the drive unit L. A timing belt 23 is stretched between the drive shaft 21 and the driven shaft 22 via a timing pulley, and a side plate 24 that supports the shift tray 202 is fixed to the timing belt 23. With this configuration, the unit including the shift tray 202 is suspended from the timing belt 23 so as to be able to move up and down.
[0040]
The drive unit L is composed of a tray lifting / lowering motor 168 and a worm gear 25, and the power generated by the tray lifting / lowering motor 168 capable of forward / reverse rotation as a driving source is a gear train fixed to the driving shaft 21 via the worm gear 25. The shift gear 202 is moved in the vertical direction by being transmitted to the final gear. Since the power transmission system is via the worm gear 25, the shift tray 202 can be held at a fixed position, and this gear configuration can prevent an accidental drop accident of the shift tray 202 and the like.
[0041]
A shielding plate 24a is integrally formed on the side plate 24 of the shift tray 202, and a fullness detection sensor 334 for detecting the full load of stacked sheets and a lower limit sensor 335 for detecting a lower limit position are disposed below the shielding plate 24a. Thus, the fullness detection sensor 334 and the lower limit sensor 335 are turned on / off. The fullness detection sensor 334 and the lower limit sensor 335 are photosensors, and are turned on when blocked by the shielding plate 24a. In FIG. 3, the shift paper discharge roller 6 is omitted.
[0042]
As shown in FIG. 2, the swing mechanism of the shift tray 202 includes a shift motor 169 and a shift cam 31. By rotating the shift cam 31 using the shift motor 169 as a drive source, the shift tray 202 can eject paper. Reciprocates in a direction perpendicular to the direction. A pin 31 a is set up on the shift cam 31 at a position away from the center of the rotation shaft, and the other end of the pin 31 a is loosely fitted in the elongated hole 32 b of the engagement member 32 a of the end fence 32. The engaging member 32a is fixed to the back surface of the end fence 32 (the surface on which the shift tray 202 is not located) and reciprocates in a direction perpendicular to the paper discharge direction according to the rotational position of the pin 31a of the shift cam 31. As a result, the shift tray 202 also moves in a direction perpendicular to the paper discharge direction. The shift tray 202 stops at two positions on the front side and the back side in FIG. 1 (corresponding to an enlarged view of the shift cam 31 in FIG. 2), and the stop control detects the notch of the shift cam 31 by the shift sensor 336. This is performed by controlling the shift motor 169 on and off based on the detection signal.
[0043]
On the front side of the end fence 32, a guide protrusion 32c for the shift tray 202 is provided, and the rear end portion of the shift tray 202 is loosely fitted to the protrusion 32c so as to freely move up and down. 202 is supported by the end fence 32 so that it can move up and down and can reciprocate in a direction perpendicular to the paper transport direction. The end fence 32 has a function of guiding the trailing edge of the loaded paper on the shift tray 202 and aligning the trailing edges.
[0044]
1.2.2 Paper Discharge Part FIG. 4 is a perspective view showing the structure of the paper discharge part to the shift tray 202.
[0045]
1 and 4, the shift paper discharge roller 6 has a driving roller 6a and a driven roller 6b. The driven roller 6b is supported on the upstream side in the paper discharge direction and is provided with an open / close guide plate that can swing up and down. 33 is rotatably supported at the free end portion. The driven roller 6b abuts on the driving roller 6a by its own weight or urging force, and the paper is nipped between the rollers 6a and 6b and discharged. When the bound sheet bundle is discharged, the open / close guide plate 33 is pulled upward and returned at a predetermined timing. This timing is determined based on the detection signal of the shift paper discharge sensor 303. Is done. The stop position is determined based on the detection signal of the paper discharge guide plate opening / closing sensor 331 and is driven by the paper discharge guide plate opening / closing motor 167. The discharge guide plate opening / closing motor 167 is driven and controlled by turning on / off a discharge guide plate opening / closing limit switch 332.
[0046]
1.3 Stipple Processing Tray 1.3.1 Overall Configuration of Stipple Processing Tray The configuration of the stipple processing tray F that performs stipple processing will be described in detail.
[0047]
FIG. 5 is a plan view of the staple processing tray F viewed from a direction perpendicular to the sheet conveying surface, FIG. 6 is a perspective view showing the staple processing tray F and its driving mechanism, and FIG. 7 is a perspective view showing the sheet bundle discharging mechanism. It is. First, as shown in FIG. 6, the sheets guided to the staple processing tray F by the staple discharge roller 11 are sequentially stacked on the staple processing tray F. In this case, alignment in the vertical direction (paper conveyance direction) is performed by the tapping roller 12 for each sheet, and alignment in the horizontal direction (direction perpendicular to the sheet conveyance direction—also referred to as the sheet width direction) is performed by the jogger fence 53. The end-face stitching stapler S1 is driven by a staple signal from the control device (see FIG. 16) between job breaks, that is, between the last sheet of the sheet bundle and the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle subjected to the binding process is immediately sent to the shift paper discharge roller 6 by the discharge belt 52 with the discharge claw 52a protruding, and is discharged to the shift tray 202 set at the receiving position.
[0048]
1.3.2 As shown in FIG. 7, the paper discharge mechanism discharge claw 52 a has its home position detected by the discharge belt HP sensor 311, and the discharge belt HP sensor 311 is attached to the discharge belt 52. It is turned on / off by the provided release claw 52a. Two discharge claws 52a are arranged at opposing positions on the outer periphery of the discharge belt 52, and the sheet bundle stored in the staple processing tray F is moved and conveyed alternately. Further, if necessary, the discharge belt 52 is rotated in the reverse direction, and the sheet bundle stored in the staple processing tray F on the back side of the discharge claw 52a and the discharge claw 52a 'on the opposite side waiting to move the sheet bundle. It is also possible to align the tips in the transport direction. Therefore, the discharge claw 52a also functions as a means for aligning the sheet bundle in the sheet conveyance direction.
[0049]
Further, as shown in FIG. 5, the discharge belt 52 driven by the discharge motor 157 has a discharge belt 52 and its drive pulley 62 arranged at the alignment center in the paper width direction with respect to the drive pulley 62. The discharge roller 56 is arranged and fixed symmetrically. Further, the peripheral speed of these discharge rollers 56 is set to be higher than the peripheral speed of the discharge belt 52.
[0050]
1.3.3 Processing Mechanism As shown in FIG. 6, the hitting roller 12 is swung around the fulcrum 12a and is given a pendulum motion by a SOL (solenoid) 170, and acts intermittently on the paper fed into the staple processing tray F. Then, the sheet is abutted against the rear end fence 51. The hitting roller 12 rotates counterclockwise.
[0051]
The jogger fence 53 is driven via a timing belt by a jogger motor 158 capable of forward and reverse rotation, and reciprocates in the paper width direction.
[0052]
As can be seen from the perspective view showing the stapler S1 of FIG. 8 together with the moving mechanism, the end-face stitching stapler S1 is driven via a timing belt by a forward / reversely movable stapler moving motor 159 to bind a predetermined position of the sheet end. Move in the paper width direction. A stapler movement HP sensor 312 for detecting the home position of the end face binding stapler S1 is provided at one end of the movement range. Controlled by Further, as shown in the perspective view of FIG. 9, the end-face stitching stapler S1 is configured to change only the stitching mechanism portion of the stapler S1 at the home position so that the needle driving angle can be changed parallel to or obliquely with respect to the sheet edge. It is configured so that the staple needle can be easily exchanged by rotating at an angle. The stapler S1 is rotated obliquely by the oblique motor 160, and when the needle replacement position sensor 313 detects that the needle replacement position sensor 313 reaches a predetermined oblique angle or the needle replacement position, the oblique motor 160 stops. When the diagonal hitting is completed or the needle replacement is completed, it is rotated to the original position to prepare for the next staple.
[0053]
As shown in FIGS. 1 and 5, the saddle stitching stapler S2 is a distance in which the distance from the rear end fence 51 to the needle striking position of the saddle stitching stapler S2 corresponds to half of the conveyance direction length of the maximum sheet size that can be saddle stitched. The two are arranged as described above, and two are arranged symmetrically with respect to the alignment center in the paper width direction, and are fixed to the stay 63. Since the saddle stitching stapler S2 itself is a known configuration, a detailed description thereof will be omitted here. However, when performing saddle stitching, the jogger fence 53 aligns the direction perpendicular to the sheet conveyance direction and strikes the trailing edge fence 51. After the transport direction of the roller 12 paper is aligned, the discharge belt 52 is driven and the trailing end of the paper bundle is lifted by the discharge claw 52, and the central portion of the paper bundle in the transport direction is positioned at the binding position of the saddle stitching stapler S2. And stop at this position to execute the binding operation. Then, the bound sheet bundle is conveyed to the middle folding processing tray G side and folded in half. Details will be described later.
[0054]
In the figure, reference numeral 64a denotes a front side plate, 64b denotes a rear side plate, and reference numeral 310 denotes a paper presence / absence sensor that detects the presence / absence of paper on the staple processing tray F.
[0055]
1.4 Sheet Bundle Deflection Mechanism The sheet bundle on which saddle stitching is performed in the staple processing tray F is folded in the center of the sheet. This middle folding is performed in the middle folding processing tray G. For this purpose, it is necessary to transport the bound sheet bundle to the middle folding processing tray G. In this embodiment, a sheet bundle deflecting unit is provided on the most downstream side in the conveyance direction of the staple processing tray F, and conveys the sheet bundle to the middle folding processing tray G side.
[0056]
The sheet bundle deflection mechanism includes a branch guide plate 54 and a movable guide 55 as shown in the enlarged views of the staple processing tray F and the middle folding processing tray G in FIGS. As shown in the operation explanatory diagrams of FIGS. 10 to 12, the branch guide plate 54 is provided so as to be swingable in the vertical direction around the fulcrum 54 a, and a rotatable pressure roller 57 is provided on the downstream side thereof. The pressure is applied to the discharge roller 56 side. Further, the position of the branch guide plate 54 is defined by the contact position with the cam surface 61 a of the cam 61 that rotates by obtaining a driving force from the bundle branch drive motor 161.
[0057]
The movable guide 55 is swingably supported on the rotation shaft of the discharge roller 56, and is linked to one end of the movable guide 55 (the end opposite to the branch guide plate 54) by a connecting portion 60a. An arm 60 is provided. The link arm 60 includes a shaft fixed to the front side plate 64a shown in FIG. 5 and a long hole portion 60b, whereby the swing range of the movable guide 55 is restricted. Further, it is held at the position shown in FIG. Further, when the link arm 60 is pushed by the cam surface 61b of the cam 61 that rotates by obtaining drive from the bundle branching drive motor 161, the connected movable guide 55 rotates upward. The bundle branching guide HP sensor 315 detects the shield 61c of the cam 61 and detects the home position of the cam 61. Accordingly, the cam 61 controls the stop position by counting the drive pulses of the bundle branching drive motor 161 with the home position as a reference.
[0058]
FIG. 10 is an operation explanatory view showing the positional relationship between the branch guide plate 54 and the movable guide 55 when the cam 61 is located at the home position. The guide surface 55 a of the movable guide 55 has a function of guiding the paper in the path to the shift paper discharge roller 6. In FIG. 11, as the cam 61 rotates, the branch guide plate 54 rotates counterclockwise (downward) in the drawing around the fulcrum 54a, and the pressure roller 57 contacts and presses the discharge roller 56 side. It is an operation explanatory view showing the state.
[0059]
In FIG. 12, when the cam 61 further rotates, the movable guide 55 rotates in the clockwise direction (upward) in the figure, and the path leading from the staple processing tray F to the half-fold processing tray G is guided along the branch guide plate 54 and the movable guide. FIG. FIG. 5 shows the positional relationship in the depth direction.
[0060]
In this embodiment, the branch guide plate 54 and the movable guide 55 are operated by a single drive motor. However, each drive motor is provided so that the movement timing and stop position can be controlled according to the paper size and the number of sheets to be bound. You may do it.
[0061]
1.5 Middle Fold Processing Tray 1.5.1 Configuration of Each Part FIGS. 13 and 14 are diagrams for explaining the operation of the moving mechanism of the folding plate 74 for performing the middle folding.
[0062]
The folding plate 74 is supported by loosely fitting the long hole portions 74 a to the two shafts 64 c erected on the front and rear side plates 64 a and 64 b, and the shaft portion 74 b erected from the folding plate 74 is further linked to the link arm 76. When the link arm 76 swings about the fulcrum 76a, the folding plate 74 reciprocates left and right in FIG. 13 and FIG. That is, the shaft portion 75b of the folding plate driving cam 75 is loosely fitted in the long hole portion 76c of the link arm 76, and the link arm 76 swings due to the rotational movement of the folding plate driving cam 75. 15, the folding plate 74 reciprocates in a direction perpendicular to the upper and lower bundle conveyance guide plates 91 and 92.
[0063]
The folding plate driving cam 75 is rotated in the direction of the arrow in FIG. 13 by the folding plate driving motor 166. The stop position is determined by detecting both end portions of the half-moon shaped shielding portion 75a by the folding plate HP sensor 325.
[0064]
FIG. 13 shows the home position position completely retracted from the sheet bundle accommodation area of the processing tray G. When the folding plate drive cam 75 is rotated in the direction of the arrow, the folding plate 74 moves in the direction of the arrow and protrudes into the sheet bundle accommodation area of the processing tray G. FIG. 14 shows a position where the center of the sheet bundle of the processing tray G is pushed into the nip of the folding roller 81. When the folding plate drive cam 75 is rotated in the direction of the arrow, the folding plate 74 moves in the direction of the arrow and retracts from the sheet bundle accommodation area of the processing tray G.
[0065]
In this embodiment, it is assumed that the sheet folding is performed by folding the sheet bundle. However, the present invention can be applied to the case of folding one sheet. In this case, saddle stitching is not required for only one sheet, so when one sheet is discharged, the sheet is fed to the middle folding processing handle G side, folded by the folding plate 74 and the folding roller, and discharged to the lower tray. To do.
[0066]
1.6 Folding Mechanism FIG. 16 is a perspective view showing the folding mechanism portion, in which one side of the folding mechanism portion is omitted, and side plates and the like serving as structures are omitted. FIGS. 17 and 18 are side views of the folding mechanism shown in FIG. 16, a part of which is seen through, and side plates and the like are omitted.
[0067]
In these drawings, the folding rollers 81a and 81b are supported by swing arms 46a and 46b of fulcrums 44c and 44d coaxial with the folding roller driving gears 44a and 44b, respectively. A pressure spring 47 is mounted as an elastic urging means on the free ends of the swing arms 46a and 46b. The free springs are elastically urged in a direction to bring the free ends close to each other, and pressure is applied between the nips of the folding rollers 20a and 20b. It has been. The folding rollers 81a and 81b are provided with folding roller gears 43a and 43b coaxially and mesh with the folding roller driving gears 44a and 44b, respectively, and are driven by rotating the folding roller driving gears 44a and 44b from a driving unit (not shown). The folding rollers 20a and 20b are driven. As the drive unit, for example, a drive motor and a reduction gear train, a timing belt, or the like is generally used.
[0068]
As shown in FIG. 16, the folding roller gears 43a and 43b are provided with smooth folding roller guide roller portions 45a and 45b having the same outer diameter, which are coaxially and integrally provided, and in this portion, the sliding of the folding plate slider 40 is guided. To do. The fold plate slider 40 has a fold plate slider guide groove 40b, and an arrow shown by the mechanism shown in FIGS. 13 and 14 along a slider guide pin 42 and slider guide rollers 41a and 41b fixed to a side plate (not shown). Advance in the direction and move backwards. The folding plate 74 is integrally extended along the advancing and retreating direction of the folding plate 74 at the center of the rear end side of the folding plate slider 40, and is moved between the nips of the folding rollers 81 a and 81 b as the folding plate slider 40 advances and retracts. On the other hand, advance and retreat.
[0069]
The fold plate slider 40 has a fold plate slider inclined portion 40a on the surface that slides with the fold roller guide roller portions 41a and 41b, and the fold plate slider 4 is pushed near the nip of the fold rollers 81a and 81b. Thus, the folding roller guide roller portions 41a and 41b are pushed by the folding plate slider inclined portion 40a, and the nip between the folding rollers 81a and 81b is expanded.
[0070]
FIG. 17 corresponds to FIG. 13 and shows a state of the standby position in which the folding plate 74 is retracted. A nip pressure is applied to the folding rollers 81a and 81b by a pressure spring 47 applied to the free ends of the folding roller swing arms 46a and 46b, but the folding roller guide roller portions 45a and 45b are connected to the folding plate slider 40. The nip pressure when there is no paper is relaxed.
[0071]
FIG. 18 corresponds to FIG. 14 and shows a state in which the folding plate 74 has advanced, in this case the folding operation is performed without a sheet bundle. In this state, the folding plate slider 40 advances in the direction indicated by the arrow, and the folding plate 74 enters the nip between the folding rollers 81a and 81b. In this state, the folding roller guide roller portions 45a and 45b are pushed by the folding plate slider inclined portion 40a of the folding plate slider 40 to widen the nip between the folding rollers 81a and 81b. The folding plate 74 is set wider than the thickness of the front end portion thereof, so that it does not interfere with the folding rollers 81a and 81b even if the folding plate 74 enters deeper than the nip between the folding rollers 81a and 81b.
[0072]
2. As shown in FIG. 16, the control device control device 350 is composed of a microcomputer having a CPU 360, an I / O interface 370, etc., and each switch of the control panel of the image forming apparatus PR main body, the inlet sensor 301, the upper paper discharge. Sensor 302, shift paper discharge sensor 303, pre-stack sensor 304, staple paper discharge sensor 305, paper presence sensor 310, discharge belt home position sensor 311, staple movement home position sensor 312, stapler oblique home position sensor 313, bundle branch guide home Position sensor 315, bundle arrival sensor 321, movable rear end fence home position sensor 322, folding portion passage sensor 323, lower paper discharge sensor 324, folding plate home position sensor 325, paper surface detection sensor 33 , 330a, 330b, signals from the sensors such as the sheet discharge guide plate close sensor 331 can be input to CPU360 via the I / O interface 370.
[0073]
The CPU 360 drives the tray lifting / lowering motor 168 for the shift tray 202, the discharge guide plate opening / closing motor 167 for opening / closing the opening / closing guide plate, the shift motor 169 for moving the shift tray 202, and the tapping roller 12 based on the input signal. The unillustrated tapping roller motor, solenoids such as tapping SOL 170, a conveying motor for driving each conveying roller, a discharging motor for driving each discharging roller, a discharging motor 157 for driving the discharging belt 52, and an end face binding stapler S1 are moved. The stapler moving motor 159, the oblique motor 160 that obliquely rotates the end-face stitching stapler S1, the jogger motor 158 that moves the jogger fence 53, the bundle branch drive motor 161 that rotates the branch guide plate 54 and the movable guide 55, and the bundle is conveyed. Drive the transport roller Controls driving of a bundle conveying motor, a rear end fence moving motor (not shown) that moves the movable rear end fence 73, a folding plate driving motor 166 that moves the folding plate 74, a folding roller driving motor (not shown) that drives the folding roller 81, and the like. . A pulse signal of a not-shown staple conveyance motor that drives the staple discharge roller is input to the CPU 360 and counted, and the hitting SOL 170 and the jogger motor 158 are controlled according to this count. The folding roller drive motor is a stepping motor and is controlled directly from the CPU 360 via a motor driver or indirectly via an I / O 370 and a motor driver.
[0074]
The punch unit 100 also performs drilling according to instructions from the CPU 360 by controlling the clutch and the motor.
[0075]
The sheet post-processing device PD is controlled by the CPU 360 executing a program written in a ROM (not shown) while using a RAM (not shown) as a work area.
[0076]
3. Hereinafter, the operation of the sheet post-processing apparatus according to the present embodiment executed by the CPU 360 will be described.
[0077]
In the present embodiment, the following discharge mode is adopted according to the post-processing mode. In this embodiment, the following discharge mode is adopted according to the post-processing mode.
[0078]
{Circle around (1)} Non-stipple mode a: a mode in which a sheet is conveyed by the conveying rollers 3 and 4 through the conveying path A and the conveying path B and discharged to the upper tray 201.
[0079]
{Circle around (2)} Non-stipple mode b: a mode in which the paper passes through the transport path A and the transport path C, is transported to the shift paper discharge roller 6 by the transport roller 5, and is discharged to the shift tray 202.
[0080]
{Circle around (3)} Sort / Stack Mode: Passes through the transport path A and transport path C, is transported to the shift discharge roller 6 by the transport roller 5, and is discharged to the shift tray 202. At that time, the shift tray 202 sorts the sheets to be discharged by swinging in the direction orthogonal to the paper discharge direction at every section separation.
[0081]
{Circle around (4)} Stipple mode: A mode in which alignment and binding are performed on the processing tray F through the transport path A and transport path D, and the paper is discharged to the shift tray 202 through the transport path C.
[0082]
(5) Saddle binding bookbinding mode: alignment and center binding are performed on the processing tray F via the transport path A and transport path D, and further center folding is performed on the processing tray G, and the paper is discharged to the lower tray 203 through the transport path H. Mode.
[0083]
Since the folding process is not performed in the non-stipple mode or the stipple mode, the description thereof is omitted here.
[0084]
20 to 27 are operation explanatory views showing operations in the saddle stitch binding mode. In these drawings, the folding plate slider 40 is omitted for the sake of brevity. In the saddle stitching bookbinding mode, the paper sorted from the conveyance path A by the branching claw 15 and the branching claw 16 is guided to the conveyance path D by the conveyance roller pair 7 and 9.10, and the conveyance roller 7 conveyance roller 9 conveyance roller 10 staple discharge. The paper is discharged to the processing tray F by the paper roller 11. In the processing tray F, the sheets sequentially discharged by the discharge rollers 11 are aligned (FIG. 20). Thereafter, the sheet bundle is carried downstream by a predetermined distance set for each sheet size by the discharge claw 52a, and the center thereof is bound by the saddle stitching stapler S2 (FIG. 21). The bound sheet bundle is conveyed downstream by a discharge claw 52a for a predetermined distance set for each sheet size, and the leading end of the sheet bundle is sandwiched between a discharge roller 56 and a pressure roller 57, and a branch guide plate 54 and a movable guide 55 Is rotated downstream again by the discharge claw 52a and the discharge roller 56 (FIGS. 22 and 23). The discharge roller 56 is provided on the drive shaft of the discharge belt 52 and is driven in synchronization with the discharge belt 52. Then, the sheet bundle is moved from the home position to a position corresponding to the sheet size in advance by the upper bundle conveying roller 71 and the lower bundle conveying roller 72, and is stopped so as to guide the lower end surface. Up to 73. At this time, the discharge claw 52a stops at the position where another discharge claw 52a 'disposed at a position facing the outer periphery of the discharge belt 52 reaches the vicinity of the rear end fence 51, and the branch guide plate 54 and the movable guide 55 returns to the home position and prepares for the next sheet.
[0085]
The sheet bundle abutted against the movable rear end fence 73 is released from the pressurization of the lower bundle conveying roller 72 (FIG. 24). After that, the vicinity of the bound needle portion is pushed by the folding plate 74 in a substantially right angle direction and guided to the nip of the opposing folding roller 81 (FIG. 25). The folding roller 81 that has been rotated in advance folds the center of the sheet bundle by conveying the sheet bundle under pressure. The leading end of the folded sheet bundle enters the nip portion of the second folding roller 82 (FIG. 26). At this time, the folding roller 81 and the second folding roller 82 stop rotating, and are conveyed again after a predetermined time. Then, folding is strengthened by the second pair of folding rollers 82, and the sheet is discharged to the lower tray 203 by the lower sheet discharge roller 83 (FIG. 27). At this time, when the rear end of the sheet bundle is detected by the folding portion passage sensor 323, the folding plate 74 and the movable rear end fence 73 are returned to the home position, and the pressurization of the lower bundle conveying roller 72 is restored, and the next sheet is detected. Prepare for. If the next job is the same sheet size and the same number of sheets, the movable rear end fence 73 may stand by at that position. The movable rear end fence can be moved up and down by a motor (not shown) between the pulleys 73a and 73b by a timing belt 73c stretched between the pair of pulleys 73a and 73b.
[0086]
4). Operation of Folding Mechanism FIGS. 28 to 31 are operation explanatory views showing the operation of the folding mechanism according to the embodiment of the present invention.
[0087]
FIG. 28 is a view (corresponding to FIG. 24) showing a state in which the sheet bundle P is conveyed to the center folding portion. As shown in FIG. 21, the sheet bundle P is saddle stitched (stipple stitched) by the saddle stitching stapler S2 as shown in FIG. 21, and the rear end of the sheet bundle P is moved by the movable fence 73 according to the sheet size signal sent from the image forming apparatus PR main body. It is positioned. From this state, as shown in FIG. 29, the folding plate slider 40 moves in the direction indicated by the arrow, the folding plate 74 fixed to the folding plate slider 40 folds the stipple position of the sheet bundle P, and the folded leading end is moved. The sheet is pushed between the nips of the folding rollers 81a and 81b. Accordingly, the folding roller drive gears 44a and 44b are rotated in the direction of the arrow by the power from the driving unit (not shown), thereby rotating the folding roller gears 43a and 43b, and the folding rollers 81a and 81b feed the sheet bundle P at the same speed. Rotates so that it is sandwiched between nips. The folding rollers 81a and 81b in which the sheet bundle P is sandwiched widen the nip interval by the thickness of the sheet bundle P, but the folding plate slider 40 is regulated in the thickness direction of the sheet bundle P by the slider guide rollers 41a and 41b, and the slider guide Since the central portion in the thickness direction is regulated by the pin 42, the folding rollers 81a and 81b spread evenly up and down around the folding plate 74 by the rotation of the folding roller swing arms 46a and 46b.
[0088]
FIG. 30 shows the state in which the folding plate 74 has pushed the sheet bundle P as far as it will go. That is, the folding plate guide 40 advances from the state of FIG. 29 in the direction of the arrow in the drawing, and the folding plate 74 advances to the innermost position. In the figure, the fold plate slider inclined portion 40a appears to be in contact with the fold roller guide roller portions 45a and 45b, but in reality, the amount of spread between the nips of the fold rollers 81a and 81b is larger with the thickness of the sheet bundle P. The sheet bundle P is sufficiently subjected to a nip pressure for folding. In this state, the folding rollers 81a and 81b continue to rotate and pinch and convey the sheet bundle P.
[0089]
When the folding plate 74 is advanced to the maximum extent in this way, the folding plate 74 is retracted as shown in FIG. 31, and the folding plate 74 is detached from between the sheets. On the other hand, the folded sheet bundle P is conveyed by the rotation of the folding rollers 81a and 81b, and is discharged and stacked on the lower discharge tray 203 from the state shown in FIG.
[0090]
In the operation of the present embodiment, the folding plate 74 is pushed in and pushed, the rotation speed of the folding rollers 81a and 81b, the drawing (retracting) timing and the drawing (retracting) speed of the folding plate 74 are the folding plate slider 40. By making the driving of the folding roller drive gears 44a and 44b independent drive systems, it is possible to arbitrarily set the number of paper bundles P and the paper size by the signal sent from the image forming apparatus PR main body.
[0091]
【The invention's effect】
As described above, according to the present invention, it is possible to securely bite the sheet bundle and fold it symmetrically and beautifully with respect to the folding position by the folding plate. In addition, it is possible to perform reliable half-folding with a simple mechanism, and it is possible to perform a smaller and higher quality saddle stitch bookbinding process.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a system configuration of an image processing system including a sheet processing apparatus and an image forming apparatus mainly showing a sheet post-processing apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view of a main part showing details of a shift mechanism of the sheet post-processing apparatus according to the embodiment of the present invention.
FIG. 3 is an enlarged perspective view of a main part of a shift tray lifting mechanism of the sheet post-processing apparatus according to the embodiment of the present invention.
FIG. 4 is a perspective view illustrating a structure of a paper discharge unit to a shift tray of the paper post-processing apparatus according to the embodiment of the invention.
FIG. 5 is a plan view of a staple processing tray of the sheet post-processing apparatus according to the embodiment of the present invention as viewed from a direction perpendicular to a sheet conveying surface.
FIG. 6 is a perspective view showing a staple processing tray and its driving mechanism of the sheet post-processing apparatus according to the embodiment of the present invention.
FIG. 7 is a perspective view showing a sheet bundle discharging mechanism of the sheet post-processing apparatus according to the embodiment of the present invention.
FIG. 8 is a perspective view showing an end-face binding stapler of the sheet post-processing apparatus according to the embodiment of the present invention together with a moving mechanism.
9 is a perspective view showing an oblique rotation mechanism of the end-face stitching stapler in FIG. 8. FIG.
FIG. 10 is an operation explanatory diagram of a sheet bundle deflection mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state when a sheet or a sheet bundle is discharged to a shift tray.
11 is an operation explanatory view of the sheet bundle deflecting mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state where the branch guide plate is rotated to the discharge roller side from the state of FIG.
12 is an operation explanatory view of the sheet bundle deflecting mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, in which the movable guide rotates to the branch guide plate side from the state of FIG. The state which formed the path | route which deflects a bundle | flux is shown.
FIG. 13 is an operation explanatory view of a folding plate slider and a folding plate moving mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state before entering a middle folding operation.
FIG. 14 is an operation explanatory view of a folding plate slider and a folding plate moving mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state when returning to the initial position after half-folding.
FIG. 15 is a diagram illustrating details of a staple processing tray and a half-fold processing tray of the sheet post-processing apparatus according to the embodiment of the present invention.
FIG. 16 is a block diagram showing a control circuit of the sheet post-processing apparatus according to the embodiment of the present invention together with the image forming apparatus.
FIG. 17 is a main part perspective view showing a folding mechanism part of the sheet post-processing apparatus according to the embodiment of the present invention;
18 is a side view showing an initial state of the folding mechanism section shown in FIG. 17;
FIG. 19 is a side view showing a state of the folding mechanism section shown in FIG. 17 during a folding operation.
FIG. 20 is an operation explanatory diagram showing an operation in the middle folding processing mode, and shows a state when the end face of the paper is prevented from being displaced by the jogger fence.
FIG. 21 is an operation explanatory diagram showing an operation in the middle folding processing mode, and shows a state when performing saddle stitching with a saddle stitching stapler;
FIG. 22 is an operation explanatory view showing the operation in the middle folding processing mode, and shows a state when the branch guide plate and the movable guide plate are closed and the sheet bundle is guided to the middle folding processing tray.
FIG. 23 is an operation explanatory diagram showing an operation in the middle folding processing mode, and shows a state in which a sheet bundle is conveyed to the middle folding portion.
FIG. 24 is an operation explanatory view showing the operation in the middle folding processing mode, and shows a state when the sheet bundle is positioned at the middle folding position of the middle folding portion and the middle folding is started.
FIG. 25 is an operation explanatory view showing the operation in the middle folding processing mode, and shows a state in which the folding plate slider has moved and the leading end of the folding plate has been pushed between the folding nips.
FIG. 26 is an operation explanatory view showing the operation in the middle folding processing mode, and shows a state in which the folding plate pushes the sheet bundle to the farthest.
FIG. 27 is an operation explanatory view showing the operation in the middle folding processing mode, and shows a state in which the folding plate is retracted and separated from between the sheets.
FIG. 28 is an operation explanatory view showing the operation of the folding mechanism according to the embodiment of the present invention, and shows a state where the sheet bundle is conveyed to the middle folding portion.
FIG. 29 is an operation explanatory view showing the operation of the folding mechanism according to the embodiment of the present invention, and shows a state in which the folding plate slider moves and the leading end portion where the folding plate is folded is pushed between the nips of the folding rollers.
FIG. 30 is an operation explanatory view showing the operation of the folding mechanism according to the embodiment of the present invention, showing a state in which the folding plate pushes the sheet bundle to the farthest.
FIG. 31 is an operation explanatory view showing the operation of the folding mechanism according to the embodiment of the present invention, showing a state in which the folding plate is retracted and separated from between the sheets.
[Explanation of symbols]
40 Folding plate sliders 40a and 40b Folding plate slider inclined portions 41a and 41b Guide rollers 42 Guide pins 43a and 43b Folding roller gears 44a and 44b Folding roller driving gears 44c and 44d Folding points 45a and 45b Guide rollers 46a and 46b Swing arm 47 74 Folding plates 81a, 81b Folding rollers

Claims (8)

In a paper folding device that folds a sheet by bringing the folding plate into contact with the sheet surface of the sheet or sheet bundle from a direction substantially perpendicular to the nip of the pair of folding rollers,
A pair of arms supported at one end in a freely swingable manner and elastically biased in directions approaching each other at the other end;
A folding roller rotatably supported by the one arm;
A guide roller provided coaxially with the folding roller;
An advancing / retreating guide disposed between the pair of guide rollers and performing advancing / retreating operation in conjunction with advancing / retreating operation of the folding plate;
And the folding roller is supported by the arm so that the folding roller moves substantially symmetrically with respect to a surface of the folding plate extending in the advancing and retreating direction. The sheet folding apparatus according to claim 1, further comprising a regulating unit that regulates a guide position and direction of the advance / retreat guide. The regulating means is
A guide groove drilled in a length corresponding to the movement distance of the advance / retreat guide along the central longitudinal direction, and a guide pin inserted into the guide groove;
A pair of guide rollers provided in parallel with the axial direction of the pair of folding rollers and in contact with both ends sandwiching the guide groove of the advance / retreat guide;
The sheet folding apparatus according to claim 2, comprising: A cam is formed on the contact surface of the guide roller of the advance / retreat guide so that the nip of the folding roller is separated when the front end of the folding plate is pushed to the vicinity of the nip of the pair of folding rollers. The paper folding apparatus according to claim 1. When the folding plate enters between the nips of the pair of folding rollers, the shape of the cam is set so as to be at least larger than the thickness of the entrance portion of the folding plate to the nip portion. The sheet folding device according to claim 4. The sheet folding apparatus according to claim 1, wherein the folding plate is provided integrally with the advance / retreat guide. A binding means for binding the central portion of the sheet bundle;
The folding device according to any one of claims 1 to 6,
A sheet processing apparatus comprising: A sheet processing apparatus according to claim 7;
An image forming apparatus that forms a visible image on paper;
Is formed as a single body or as a separate body.

Images