JPH0977361A - Paper handling device and image forming device provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper handling device which can fold a sheet tightly and an image forming device provided with it. SOLUTION: A sheet (S) is folded selectively one time or more by folding means 238, 239 to be a predetermined size and the folded part 251A of the sheet (S) is pressed again by pressing means 246, 247 disposed in a transfer path 240 through which the sheet (S) is transferred to a receiving plate such that it is tightly folded. Since the pressing means 246, 247 comprise a pair of rollers and are disposed in a nearly straight path 240 for discharging paper, when the sheet is folded two times or more, the front end and folding part of the sheet are passed the pressing means 246, 247 at the same time, thereby not making the other folding line on the folded part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet processing apparatus for folding sheets sequentially discharged from an image forming apparatus and an image forming apparatus including the sheet processing apparatus.

[0002]

2. Description of the Related Art There is a conventional sheet processing apparatus in which sheets sequentially discharged from an image forming apparatus are selectively bent to a predetermined size and then stacked on a sheet tray. The folding means for folding the sheet in this way is located upstream of the sheet tray, and the folded sheet is conveyed to the sheet tray through the conveying passage.

[0003]

By the way, in such a conventional sheet processing apparatus, the folding height becomes high when folding by the folding means is unsatisfactory, and a sheet having such a high folding height is fed to the sheet tray. When the sheets are stacked on the sheet tray, the stacked state becomes unstable, so that there is a problem that the amount of sheets that can be stacked on the sheet tray is limited.

It is also possible to increase the folding pressure of the pair of folding rollers so that the folding is not apt to occur. However, in order to increase the folding pressure in this way, a large folding pressure generating mechanism is required. If the folding pressure generating mechanism is provided, another problem that the sheet processing apparatus becomes large-sized occurs.

Therefore, the present invention has been made to solve such a problem, and provides a sheet processing apparatus and an image forming apparatus including the sheet processing apparatus, which can fold a sheet without the folding being unfavorable. The purpose is.

[0006]

According to the present invention, in a sheet processing apparatus in which a discharged sheet is selectively bent and then conveyed to a sheet tray, the sheet is located upstream of the sheet tray and A folding means for folding the sheet into a predetermined size at least once and a pressurizing means provided in a conveying path for conveying the sheet having the predetermined size to the sheet tray, and applying a folding pressure to the folding portion of the sheet again. , Is provided.

Further, the present invention is characterized in that the pressing means comprises a roller pair, and the pressing means is provided in a substantially straight conveying path.

The present invention further provides an image forming apparatus comprising an image forming section for forming an image on a sheet and a sheet processing apparatus for post-processing a sheet image-formed by the image forming section. The sheet processing apparatus is the sheet processing apparatus according to claim 1.

With such a structure, the folding means located upstream of the sheet tray selectively folds the sheet at least one or more times to a predetermined size, and at the same time, the sheet is provided in the conveying passage for conveying the sheet to the sheet tray. Folding pressure is applied again to the folded portion of the sheet by the pressurizing means so as to eliminate the foldness. Further, the pressing means is constituted by a pair of rollers, and the pressing means is provided in the substantially straight conveying path, so that when the sheet is folded twice or more, the leading end and the folded portion of the sheet simultaneously act as the pressing means. Make sure that it passes and that there are no other folds in the fold.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the internal structure of an electrophotographic copying machine which is an example of an image forming apparatus to which the present invention can be applied. In FIG. 1, reference numeral 200 is an electrophotographic copying machine. Is a copying machine main body 201 and an automatic document feeder 202 provided on the upper part of the copying machine main body 201.
And a sheet processing apparatus 203 that performs post-processing of the sheet S on which an image is formed in the copying machine main body 201. In addition, the sheet processing apparatus 203 is the folding apparatus 20.
4 and a stapling / stacking device 205.

By the way, in the electrophotographic copying machine 200, the originals 207 placed on the original placing table 206 of the automatic original feeding device 202 are separated in order from the lower side and passed on the platen glass 208 of the copying machine main body 201. The sheet is fed through the platen glass 207 and then read by the optical system 210 of the copying machine body 201.
Then, the sheet is discharged to the uppermost surface on the document table 205 via the path 211.

Further, the sheet S is fed from the deck 212 and image-formed by the image forming section 213, and then the fixing section 214.
After being fixed by the sheet, the sheet is normally passed through the folding device 204 and the sheet inlet 21 of the staple / stack device 205 is passed.
5 is to be transported. The image forming process of the copying machine 200, which is the main body of the present invention, is well known and will not be described here.

On the other hand, the sheet inlet 215 is provided with a first deflector 3 as shown in FIG. 2, and the sheet S is guided by the first deflector 3 to guide the sheet S to the upper direction. The stapling / stacking device 205 selectively advances to the second transport path 2 leading to the lower bin module B ₂ which is a sheet sorting device. In addition, the first deflector 3 is provided in the first transport path 1.
A second deflector 4 that constitutes a switchable transfer means is also provided, and the sheet S is guided by the second deflector 4 to the third transport path 6 or the stapling / stacking device 205 that guides the sheet S to the non-sort tray 5. It selectively travels to the fourth transport path 7 leading to the upper bin module B ₁ which is a sheet sorting device.

In the figure, 8a to 8p are roller pairs arranged in the respective conveying paths 1, 2, 6 and 7, and the sheet S is made up of these roller pairs 8a to 8p and the non-sort tray 5 and the upper bin. It is designed to be transported to module B ₁ and lower bin module B ₂ .

On the other hand, when the sheet is once folded by the folding device 204 and then conveyed to the stapling / stacking device 205, as shown in FIG. 3, the inlet rollers 227 and 228 are used.
Then, it is introduced into the first folding path 233 by the entrance decreter 229. By the way, this folding device 204
Has three modes, a C-folding mode, a Z-folding mode, and a through-pass mode.

The through-pass mode is a mode in which the sheet is allowed to pass without folding. When this mode is selected, the sheet carried in by the pair of inlet rollers 227 and 228 is conveyed by the inlet deflector 229 to the paper path 230.
And is delivered to the stapling / stacking device 205 by the pair of paper ejection rollers 231 and 232.

Here, the C-folding mode is to fold an LGL size sheet into two to make an LTR (vertical size), and when this mode is selected, the sheet introduced into the first folding path 233. First, the first folding path 233
A folding deflector 234 provided at the exit of the second folding path 2 moves toward the guide roller pair 237, 238 and is wound around the guide roller pair 237, 238.
It will be introduced in 36.

Next, the sheet S thus introduced into the second folding path 236 moves upward along the second folding path 236, and the leading edge of the sheet S eventually reaches the stopper 243 as shown in FIG. Upon contact, a loop 250 is formed in the central part. Then, when the sheet S is further introduced into the second folding path 236, the loop 250 becomes large and is caught in the nip between the folding rollers 238 and 239, which is a folding unit, and is drawn in the central portion on the downstream side of the sheet S. As shown in FIG. 5, a fold 251A is formed to form a half-folded sheet.

Finally, the sheet S folded in two in this way is a staple / stack device 2 for the sheet S.
_No. 05 of the upper bin module B ₁ and the lower bin module B ₂ passes through a paper discharge path 240 which is a substantially straight conveying path, and a pair of paper discharge rollers 231 and 232 (see FIG. 3) to the stapling / stacking device 205. It will be sent out.

On the other hand, in the Z-folding mode, after the sheet S is folded at a position of 1/4 from the leading end side, it is folded at a position of 1/2 from the leading end in the direction opposite to the folding direction described above. When this mode is selected, the sheet introduced into the first folding path 233 is first moved to the third direction by the folding deflector 234 which faces the guide rollers 238 and 237 in the opposite direction as shown in FIG. It is sent to the folding path 242, and its tip comes into contact with the stopper 245.

As a result, about 1 from the leading edge of the sheet S
A loop is formed at the / 4 portion, and the loop is held in the nip of the guide roller pair 238, 237 to form a fold line 251B as shown in the figure to form a folded sheet.

Next, the sheet S folded in this way is introduced into the second folding path 236, and when this fold 251B is abutted against the stopper 244, the center portion of the sheet S folded in half is brought into contact. A loop is formed in the same manner as described above, and the loop is gripped in the nip between the pair of folding rollers 238 and 239 to form the second fold 2 as shown in FIG.
51C is formed. Finally, the Z-folded sheet S folded back and forth passes through the paper ejection path 240 and is delivered to the stapling / stacking device 205 by the paper ejection roller pairs 231 and 232.

By the way, the paper discharge path 240 is provided with a pair of pressure rollers 246 and 247 as a pressure means as shown in FIGS. 3, 4 and 6, and is folded in each folding mode. Before reaching the sheet discharge roller pair 231, 232, the sheet S is re-forced by the pressure roller pair 246, 247.

Then, by applying the folding pressure again to the folds 251A, 251B, 251C which are the folded portions of the sheet S folded in this way, it is possible to prevent the folding from becoming blunt, and thus the folding height can be increased. Can be lowered and the seat S can be moved to the upper bin module B.
₁ and the lower bin module B ₂ can be loaded in a stable state.

It should be noted that this pressure roller pair is used as the paper discharge path 24 of the folding roller pair 238, 239 as shown in FIG. 7, for example.
The pressure roller 246 may be pressed against the 0-side roller 239. However, in this case, a fold 251C that is folded a second time in Z-folding in which a sheet is folded twice or more. Is the paper ejection path 24
If the sheet comes into contact with the outer wall surface 240a of 0 and lags behind the sheet front end 251D due to a difference in curvature, the sheet front end 251
D and the fold line 251C simultaneously press the pressure roller pair 239,2.
It may not get into the nip of 46.

Then, in this way, the leading edge 251D of the sheet
And the fold line 251C simultaneously with the pressure roller pair 239, 24.
When it does not enter the nip of 6, the pressure roller pair 23
First fold line 251 when passing through 9,246
B will have another crease. Therefore, the pressure roller pair 246, 247 has a problem in the curved path, so that it is necessary to provide the pressure roller pair 246 in the substantially straight sheet discharge path 240.

Then, in this way, the pressure roller pair 246,
By providing 247 in the substantially straight paper discharge path 240, since the difference in curvature in the curved path does not occur, the fold line 251C is guided to the nip between the pressure roller pair 246 and 247 at the same time as the leading edge 251D of the sheet. , The desired effect is obtained.

By the way, the stapling / stacking device 20
Two bin modules B ₁ and B ₂ above and below 5 are bins B _{11 to} B _1n (n = 6 in FIGS. 1 and 2) which are a plurality of sheet trays for storing sheets as shown in FIG. Reference rods 14a, 14b, a matching wall 15, and a lifting column 16
a, 16b, 16c.

[0030] Here, the reference rod 14a, 14b in each bin B ₁₁ .about.B _1n (lower bin module B ₂ is B ₂₁
~ B _2n ) for determining a reference line for post-processing such as stapling on the sheet discharged above,
Normally, it is set to be slightly retracted from the position of the end portion when the sheet is discharged.

Further, the alignment wall 15 is provided so as to be movable in the direction perpendicular to the sheet conveying direction (the direction of arrow A in the figure), and by moving in this way, it is discharged onto each of the bins B _{11 to} B _1n. The sheets S are aligned one by one or a plurality of sheets and the opposite ends are abutted against the reference rods 14a and 14b to align the sheets S.

A shaft 22 is caulked to the alignment wall 15 as shown in FIG. 9 which is a plan view and FIG. 10 which is a side view of the alignment wall drive portion. The shaft 22 has a U-shape. It is stopped by penetrating the support plate 23. On the other hand, a compression spring 24 is installed inside the support plate 23 while being slightly biased in the compression direction.
Stopper 2 provided on the inner wall of 3 and the other on shaft 22
It is struck at 5. Then, the shaft 22 and the matching wall 15 are urged downward in FIG. 9 by the spring force of the compression spring 24.

The lower end of the support plate 23 is fixed to the moving side of a slide rail 27 consisting of two members via a slide plate 26, and the fixed side of the slide rail 27 is in the sliding direction of the alignment wall 15. It is fixed to the slide rail plate 28 that extends in the vertical direction. On the other hand, shafts 29 and 30 are projectingly provided at both ends of the slide rail plate 28, and the pulleys 3 are attached to the shafts 29 and 30, respectively.
1, 32 are attached.

Further, a timing belt 33 is passed between the pulleys 31 and 32, and the slide plate 26
Is fixed to this belt 33. The motor gear 34 of the matching wall drive motor M2 is adapted to mesh with the gear portion 31a of the pulley 31, whereby the driving force of the matching wall drive motor M2 is transmitted via both pulleys 31, 32 and the timing belt 33. The alignment wall 15 is transmitted to the alignment wall 15, and the alignment wall 15 moves in the alignment direction.

The home position of the matching wall 15 is
It is adapted to be detected by the sensor S4. Also,
In FIG. 10, reference numeral 35 denotes a guide member 35 attached to the upper end of the support plate 23.
A rail 36 fixed above the support plate 23
The movement of the support plate 23 is guided by engaging with the recessed portion.

On the other hand, lifting columns 16a, 16b, 16c
Is one on the front side of the bins B _{11 to} B _1n as shown in FIG.
Two of them are provided upright on the back side, and a spiral lead cam 16A is formed on the outer circumference. Then, the roller portion B protruding from the bins B _{11 to} B _1n into the lead cam 16A
a, Bb, with respectively engaged to Bc, each of these lifting struts 16a, 16b, by rotating in synchronization with 16c, roller portion Ba, Bb, bin B ₁₁ ~ with Bc
B _1n can be moved up and down by a predetermined pitch of the lead cam 16A.

Here, these lifting columns 16a, 16
b and 16c are rotated by the driving force of the bin shift motor M1 synchronously transmitted via the motor pulley 18, the belt 19 and the lead cam pulleys 20a, 20b and 20c shown in FIG. Then, by rotating the bin shift motor M1 in the forward and reverse directions, for example, the lifting columns 16a,
16b, by one rotation 16c, thereby making it possible to lift only one pitch bin B ₁₁ .about.B _1n lead cam 16A.

The bin shift motor M1 is a pulley 1
An encoder 21 is provided on the side opposite to 8, and the sensor S1 detects one rotation. In addition, each bin module B _1, B _2, there are home position detecting sensor (not shown), this detection sensor, the top bin B ₁₁
Are detected at the respective sheet receiving positions.

On the other hand, in each of the bins B _{11 to} B _1n , as shown in FIG. 12, notches Bd corresponding to the reference rods 14a and 14b,
In addition to the hole Be corresponding to the alignment wall 15, a notch Bf corresponding to the first-out gripper 10 described later, a notch Bg for the bin standing drive mechanism, and a notch Bh necessary for operation are formed.

By the way, as shown in FIG. 13, the bins B _{11 to} B _1n are arranged parallel to each other at a certain angle with respect to the horizontal, and the bin roller portions Ba, Bb, Bc are arranged in the bin B _11.
It is configured that all of B _1n have the same height in a tilted state. That is, the position of the bin roll Bb near the right side of the bin B ₁₁ .about.B _1n is whereas at the reference plane near the bin B ₁₁ .about.B _1n, position near bin roll Bc to the left of the bin B ₁₁ .about.B _1n Is substantially below the reference plane of the bins B _{11 to} B _1n , and the bin roller Bc is connected to the bin by a V-shaped fixed arm.

As a result, even when adjacent bins such as B ₁₅ and B ₁₆ approach each other, the interference of the arm portions can be avoided.
Further, since the bin roller portions Ba, Bb, Bc are all at the same height, the height-wise positions of the lifting columns 16a, 16b, 16c can all be set at the same height, and the overall size can be reduced.

By the way, as shown in FIG. 13 which is a side view of the bin and FIG. 14 which is a partial top view thereof, each of the bins B _{11 to} B _1n has a sheet stacking portion Bi and an inclined end of the sheet stacking portion Bi. It is composed of a matching portion Bj rotatably provided in. Here, the aligning portion Bj is rotatably held at a position substantially vertical to the normal sheet stacking portion Bi as shown by the solid line, and in this state, the aligning portion Bj is brought into contact with the rear end of the stacked sheets to align the sheets. Is for doing.

When the sheet bundle is subjected to post-processing or stacking, the stacking sheet is rotated downward by using the rotation shaft 45b as a fulcrum until it becomes substantially flush with the stacking surface of the sheet stacking portion Bi as shown by a broken line. It is possible to convey the sheet by releasing the contact with the sheet. In addition, the upright spring 4 is attached to the matching portion Bj.
01 is provided, and the aligning portion Bj is biased and held by the upright spring 401 so as not to fall down due to the weight of the stacked sheets.

By the way, the rotating shaft 45b of the matching portion Bj.
A driving arm 45 is attached to the matching arm Bj at a predetermined angle, and a pin 45a is erected at the tip of the driving arm 45. On the other hand, on the base 46, the bin standing drive solenoid SL1 is connected to the arm 48 of this solenoid SL1 via the pin 47a, and the solenoid S1 is connected to the solenoid S1.
A link 47 that is rotated from the solid line portion to the two-dot chain line portion by the operation of L1 is supported. Further, a pin contact member 47b that contacts the pin 45 at the tip of the drive arm 45 at the time of rotation is attached to the tip of the link 47.

When the sheet discharge onto the bin B is completed and the sheet bundle in the bin B is post-processed or stacked, the corresponding bin shifts to the position shown in FIG. 13, and then the solenoid SLl is operated, Accordingly, when the link 47 rotates from the solid line portion to the two-dot chain line portion, the pin abutting member 47b abuts the pin 45a of the drive arm 45 and the matching portion Bj rotates to the position of the two-dot chain line in FIG. Come to do.

As a result, the aligning portion Bj becomes substantially flush with the stacking surface, and the sheets can be conveyed. The pin contact member 47b is separated from the pin 45a in the normal state so that it does not hinder the up-and-down movement of the bin B. Further, when the solenoid SLl is turned off, the link 47 returns to the original solid line position by the action of the spring 49, and correspondingly the aligning portion Bj also returns to the position orthogonal to the stacking surface.

On the other hand, the stapling / stacking device 205
In the space K between the fourth transport path 7 to the upper bin module B ₁ and the second transport path 2 to the lower bin module B ₂ shown in FIG. The grip / stapling unit 9 is provided with a frame 9A, a first-out gripper 10, a stapler 11 and a first-out gripper 1 attached to the frame 9A.
A transport gripper 12 that constitutes a sheet bundle extracting means together with 0
And

Here, as shown in FIG. 15 which is a top view of the grip / staple unit 9 and FIG. 16 which is a front view thereof, the frame 9A includes a unit front side plate 50, a unit rear side plate 51, and these units. Two upper and lower guide stays 52 and 53 and a side stay 54 passed between the side plates 50 and 51.
It is formed by.

On both sides of the unit rear side plate 51, a total of four lifting rollers 55, two upper and two lower, are crimped.
A guide member 53a for guiding the sheet bundle when the sheet bundle is conveyed is attached to the inner side of the lower guide stay 53.

On the main body side of the staple / stacking device 205, a pair of rails 56 for vertically holding four lifting rollers 55 are erected, and each of the pair of rails 56 has a frame. A rack that meshes with a pinion gear 58 that is rotated by a forward / reverse lifting motor M4 attached to the body 9A is formed.

As a result, when the elevating motor M4 rotates in the forward and reverse directions, the pinion gear 58 meshes with the rack of the rail 56 so that the frame 9A moves up and down. Reference numeral 57 denotes a pinion gear 58 at both ends while penetrating the frame body 9A in the lateral direction.
Is attached to the frame 9A. The shaft 57 rotates the two pinion gears 58 at the same timing by the lifting motor M4 to lift and lower the frame 9A.

On the other hand, the first-out gripper 10 is attached to the frame 9A so as to be movable in the direction of arrow D so that the vicinity of the right end of the sheet bundle S on the bin on the front reference side is gripped and pulled out to the stapler 11 side. . The distance l ₄ from the right end of the advance gripper 10 to the leading end of the sheet bundle S
Is set to be longer than the distance l ₅ from the left end of the stapler 11 to the leading end of the sheet bundle S when the drawing is completed.

By the way, as shown in FIG. 12 which is a top view of the drive portion of the advance gripper 10 and FIG. 18 which is a front view thereof, a grooved roller 72 is caulked on the front side surface of the advance gripper 10. , This roller 72 is a frame 9A
Is engaged with an elongated hole 50a formed in the front side plate 50.

Here, the long hole 50a is formed by the stapler 11
18 is formed substantially horizontally on the right side of FIG. 18, while the left side of FIG. 18 near the bin is formed at an angle according to the inclination of the bin. It should be noted that, in FIGS. 17 and 18, 73 is a connecting sheet metal 73 for fixing the tip ends of the shafts of the two rollers 72, and a pin member 74 is attached to the connecting sheet metal 73.

On the other hand, on the front side of the front side plate 50, a forward-reverse rotation advance motor M7 is mounted via a mounting member 75, and a swing arm 76 is fixed to the tip of its drive shaft. A long hole 76a is formed at the tip of the swing arm 76, and the tip of the pin member 74 of the connecting sheet metal 73 is engaged with the long hole 76a.

As a result, for example, when the advance motor M7 is normally rotated for a predetermined time, the swing arm 76 moves from the two-dot chain line position shown in the same figure to the solid line position, and accordingly, the advance gripper 10 has the elongated hole 50a of the front side plate 50. It is designed to move to a horizontal position while grasping the sheet bundle along. Further, after this, when the rotation is reversed for a predetermined time, the swing arm 76 moves from the solid line position to the two-dot chain line position, and accordingly, the first-out gripper 10 separates the sheet bundle at the horizontal position and returns to the inclined position again. It has become.

On the other hand, the transport gripper 12 is the stapler 1
After being selectively stapled at 1, the front end of the bundle is movably attached to the frame 9A so as to be sandwiched by the transport gripper 12 and transported in the direction indicated by the arrow G in FIG.

By the way, the transport gripper 12 is supported by the two shafts 77, 78 at its lower position as shown in FIG. 19 which is a top view of the drive section and FIG. 20 which is a front sectional view. . Here, one shaft 77 is constituted by a ball screw and is rotatably supported by front and rear side plates 59, 60 (see FIG. 15), and the other shaft 78 is constituted by a normal shaft and front and rear side plates 59. , 60 are fixed.

Guide rollers 79 are provided on the unit front side plate 50 and the unit rear side plate 51 (see FIG. 15) of the frame 9A.
The guide rollers 79 are attached to the rear side plate 51.
It can be moved in the left-right direction along the elongated hole 5la formed in the. Although not shown, a similar elongated hole is also formed in the unit front side plate 50.

On the other hand, a conveyance gripper horizontal movement motor M8 is attached to the rear side plate 51, and the rotation of the motor M8 is transmitted to the penetrating shaft 83 via the motor pulley 80, the belt 81 and the pulley 82. There is. Here, a drive pulley 84 is provided on the front side of the through shaft 83,
One belt is attached to each of the back sides, and a belt 86 is hung between the driven pulleys 85 facing each other. Then, a part of the belt 86 is attached to the rear plate 6 by the regulating member 87.
By being fixed on 0, the drive of the motor M8 is transmitted to the transport gripper 12 and can be moved in the direction of arrow G in FIG. 15 and in the left-right direction shown by the arrow in FIG.

By the way, the transport gripper 12 is shown in FIG.
5 can be moved in the direction of arrow G, but arrow F shown in FIG.
It can be moved in any direction. Further, by making it movable also in the direction of the arrow F, it is possible to grip the approximate center position of the sheet width according to the size of the sheet bundle. As a result, when the sheets are conveyed, the sheets are first moved in the direction of arrow F, then the sheet bundle is conveyed in the direction of arrow G, and the sheet bundle is completely pulled out from the bin and conveyed to the stacker described later. ing.

Here, as shown in FIG. 19, a transport gripper forward / backward movement motor M9 is attached via a base 88 on the rear side plate 60 so that such an operation is possible. The rotation is transmitted to the ball screw shaft 77 via the motor pulley 89, the belt 90, and the pulley 91. When the ball screw shaft 77 rotates in this way, a similar screw is also cut in the portion of the transport gripper 12 that engages with the ball screw shaft 77, so that the transport gripper 12 moves forward and backward. Has become.

The position of the transport gripper 12 is determined by detecting the home position and the rotation amount of the motor M8. That is, for position control in the left-right direction, the home position sensor S7 detects the upper protrusion 87a of the regulating member 87, the sensor S8 that reads the encoder 92 of the motor M8 detects the amount of movement, and stops at a predetermined position. Is configured. In addition, the transport gripper 12
The position control in the front-back direction of the home position sensor S9
Is used to detect the negative part of the transport gripper, the sensor SlO that reads the encoder 93 of the motor M9 to detect the movement amount, and stop the transport gripper 12 at a predetermined position.

By the way, the movement of the transport gripper 12 in the direction of the arrow F is used for the purpose of sorting on the stacker, in addition to the movement corresponding to the size of the sheet as described above. That is, when the bundle is conveyed to the stacker, the conveyance amount in the arrow G direction depends on the sheet bundle size, but by changing the conveyance amount of the sheet bundle in the F direction, sorting of sheet bundles of the same size or different jobs is performed. It is possible to sort between.

The depth dimension l _{6 of the} transport gripper 12
Is set to a size such that the leading edge of the sheet bundle S can be held even when the stapler 11 is operating with respect to the sheet bundle S.

On the other hand, as shown in FIG. 21, the grip portions 61 of the advance gripper 10 and the transport gripper 12 have two side plates 62, 62 (only one side plate is shown in the figure) and three shafts 63. , 64, 65 are supported, an upper gripper 66 and a lower gripper 67 are arranged on the first shaft 65, and a lower gripper cam 68 fixed on the second shaft 63 and a third gripper 64 are fixed on the third shaft 64. Upper gripper cam 69 installed
By the rotation in the directions of and, the rocking in the directions of the arrow H and the arrow I is repeated (solid line and broken line diagrams).

The first spring member 70 has a lower gripper 67.
Cam portion 67a of the upper gripper 66 is biased to the lower gripper cam 68, and the second spring member 71 biases the cam portion 66a of the upper gripper 66 to the upper gripper cam 69 so that the contact pressure between the upper gripper and the lower gripper becomes substantially constant. Have control over. The gripper cams 69 and 68 are driven by a pinching motor (not shown).

The first-out gripper 10 and the transport gripper 12 have the same basic structure as described above, but the conditions such as the clamping pressure, the width of the gripper, and the maximum opening amount are optimally set according to the respective usage conditions. I don't mind.

For example, in the case of the present embodiment, the first-out gripper holds the width small in view of the space, but clamps only the reference side. Therefore, the clamping pressure is set high in order to prevent the misalignment of the bundle, and the opening amount is set between the bins. Hold down to enter. On the other hand, since the transport gripper can clamp the sheet bundle center, the clamping pressure can be set low. Other,
It can be generally set according to the curl amount of the sheet, the basis weight, the presence or absence of folding, the number of sheets, and the like.

On the other hand, the stapler 11 can be moved to a retracted position in the front or back that does not overlap the sheet width, or to an arbitrary position on the leading end of the sheet bundle, as shown by arrow E in FIG.
It is movably attached to the frame 9A so as to be movable in the direction.

The stapler 11 is fixed on a base 94 as shown in FIG. 22 which is a left side view of the stapler driving section and FIG. 23 which is a top view of the stapler drive section. A slider 95 is attached to the upper part. Here, the slider 95 is slidably held by two shafts 96 and 97 fixed between the unit front side plate 50 and the unit rear side plate 51 of the frame 9A.

A stapler forward / backward motor Ml0 is attached to the unit rear side plate 51 side through a motor base 98, and the rotation of the motor Ml0 is controlled by the motor gear 99,
Motor pulley 100, driven pulley 101 and both pulleys 9
The slider 9 fixed to the belt 102 by the restricting member 103 via the belt 102 passed between 9 and 100.
5, so that the stapler 11 can move in the direction of arrow J in FIG.

The stapler 11 can be stopped at any position between the retracted position 1la on the front side and the retracted position 1lb on the rear side. The position setting of the stapler 11 is performed by the position sensor on the front side. From the detection by Sll or the position sensor S12 at the back, the encoder 104 of the motor M10 is detected.
Is read by the sensor Sl3.

Then, the grip /
The staple unit 9 moves to the position shown by the broken line in FIGS. 1 and 2 after the bins B _{11 to} B ₁₆ are filled with the sheet bundle, and the first-out gripper 10 moves the sheets on the bins B _{11 to} B _16. The stack of sheets is conveyed to the right in FIGS.
After being selectively stapled at 1, the bundle tip is nipped by the transport gripper 12 and further transported to the right.

By the way, the stapling / stacking device 20
5, the sheet is conveyed to the bins B _{21 to} B ₂₆ of the lower bin module B ₂ while the bundle of sheets is taken out from the bin of the upper bin module B ₁ by the grip / staple unit 9 as described above. ing.

After the sheet bundle is taken out from the bins B _{11 to} B ₁₆ , the lower bin module B ₂ bins B _{21 to} B
After the conveyance to the sheet ₂₆ , the grip / stapling unit 9 is lowered to the solid line position in FIGS. 1 and _2, and the sheet bundle is taken out from the lower bin module B ₂ at this solid line position. Then, by repeating this operation, copying can be continuously continued until the stack unit described later becomes full.

Each bin module B₁ , B₂ In
Each bin B₁₁~ B₁₆Penetration sensor S3 that detects the upper sheet
(See FIG. 2)₁₁~
B₁₆ Module B by detecting the presence of the upper sheet₁ , B₂ 
The timing to switch the
You.

On the other hand, as shown in FIG. 2, the grip / staple unit 9 is located in the space K sandwiched between the fourth transport path 7 to the upper bin module B ₁ and the second transport path 2 to the lower bin module B _2. A stack unit 13 which is a sheet stacking device is vertically movable below the sheet stacking unit, and the stack unit 13 stores the sheet bundle transported by the transport gripper 12. The right end portion of the stapler 11 and the left end portion of the stack unit 13 substantially overlap each other in the left-right direction as shown in FIG. 2 (area of width l _{15 in} FIG. 2).

By the way, the stack unit 13 is
As shown in FIG. 24, which is a top view of the stack unit 13, FIG. 25, which is a front view thereof, and FIG. 26, which is a left side view, a stack frame 1 which is an outer frame of the stack unit 13.
05, a stack tray 116 that is a sheet stacking unit,
It has a reference wall 117 and a pressing member 118.

The stack frame 105 is composed of a rear side plate 105a, a left side plate 105b, a right side plate 105c and a bottom plate 105d. Here, the left and right side plates 1
Four lifting rollers 106 are mounted on each of the upper and lower outer surfaces of 05b and 105c, two vertically and two vertically, and are guided by rails 107 fixed to the stapling / stacking device 205 main body. In addition, this rail 1
07 is the grip / staple unit 9 shown in FIG.
The rail 56 may be made of the same material and coexist.

On the other hand, the chain 109 is held by the holding plate 108 at the inner bent portions of the left and right side plates 105b and 105c, respectively, as shown in FIGS.
These left and right chains 109 are passed between upper and lower sprockets 110 and 111, respectively.

The staple / stacking device 205 main body is fixed with a stack frame elevating motor Mll which is a sheet stacking device moving device and is capable of rotating in the forward and reverse directions. The rotation of the motor Mll is downward via gears 113 and 114. It is adapted to be transmitted to the through shaft 112 fixing the sprocket 111. As a result, the motor Ml
When 1 rotates, the lower sprocket 111 rotates, and the stack frame 105 moves up and down accordingly.

The stop positions of the stack frame 105 are usually two stop positions corresponding to the two stop positions of the grip / staple unit 9 shown in FIG. 2 (the upper broken line portion and the lower solid line portion). In addition, the stacker tray pull-out position and the stacker limit number change position are set in a plurality of places. Also, the stack frame 105
The home position of is the position corresponding to the upper bin module B ₁ , but the encoder 1 of the motor Mll is
By reading 15 with the sensor Sl4, it is possible to stop at the various setting positions.

On the other hand, the stack tray 116 is provided in the stack frame 105 so as to stack the sheet bundle conveyed by the conveying gripper 12. by the way,
When a large number of sheets are stacked, the upper surface of the sheet bundle gradually rises and eventually approaches the gripper / stapling unit 9. When the distance between the upper surface of the sheet bundle and the gripper / stapling unit 9 becomes narrower than a predetermined distance, the sheet bundle cannot be conveyed and stacked properly, and the sheet bundle is locked.

Therefore, in order to prevent such locking of the sheet bundle, after the stacking of the sheet bundle is started, the stack tray 116 is gradually adjusted so that the distance between the upper surface of the sheet bundle and the gripper / stapling unit 9 is always kept constant. I am trying to lower it.

Then, in this way, the stack tray 116
24 is a plan view of the stack tray 116 and FIG. 27 is a front view of the stack tray 116, the U-shaped roller receiving plates 131 are attached to both end surfaces of the stack tray base 129. At the same time, two rollers 132 are crimped on each roller receiving plate 131, while these rollers 132 are fixed to the side plates 105b and 105c of the stack frame 105 by rails 128.
It is supposed to be guided by.

A rack is vertically formed at one end of the rail 128, and the pinion gear 13 is attached to both ends of a shaft 133 penetrating the base 129 in the horizontal direction.
It is designed to mesh with 4. On the other hand, a stack tray lifting motor M13, which is a sheet stacking unit moving device, is attached to the stack tray base 129 via a motor base 135, and the rotation of the motor M13 is performed by the gear 13
It is adapted to be transmitted to the through shaft 133 by 6, 137.

The motor M13 can be rotated by a minute number of revolutions. As a result, when the stack tray lifting motor M13 rotates by a minute number of revolutions, the pinion gear 134 is rotated. Along with this, the stack tray 116 is gradually lowered. An encoder 138 is attached to the other end of the motor M13.
Is attached, and the amount of lowering of the stack tray 116 is controlled by reading with the sensor S15.

By the way, the stack unit 13 (the stack frame 105 in this embodiment) may be gradually lowered so as to prevent the lock of the sheet bundle, but the stack frame lifting motor Mll causes the stack unit 13 to move to the upper bin module B _1. And the lower bin module B ₂ is a motor suitable for moving a long distance at high speed, and the upper surface of the sheet bundle and the gripper / stapling unit 9
It is not suitable for gradually lowering the stack unit 13 at a low speed so as to always keep the interval between and.

Therefore, as in the present embodiment, the movement between the bin modules B ₁ and B ₂ is performed by moving the stack unit 13 at high speed by the stack frame lifting motor Mll.
By configuring the stack tray elevating motor M13 to gradually lower the stack tray 116 when stacking sheets, it is possible to perform more accurate sheet height control and improve stackability.

The stack tray 116 is constructed so that it can be pulled out toward the front by a slide 130 with respect to the stack tray base 129. When the stack unit 13 is not in operation, the stack tray 116 is pulled out toward the front. This allows the sheet bundle to be taken out arbitrarily.

On the other hand, the reference wall 117 is for regulating the rear end of the sheet bundle S stacked on the stack tray 116, as shown in FIG. In addition, FIG.
As shown in FIG.
a is rotatably supported so that the rear end of the sheet bundle does not remain on the upper inclined surface 117b of the reference wall 117. The reference wall 117 is adapted to move upward when changing the stacker limit number.

By the way, a proximity prevention sensor Sl6 is attached to the upper end of the reference wall 117 as shown in FIG. 25, and detects the distance between the stack unit 13 and the upper gripper / stapling unit 9, When they are close to each other within a certain distance, control is performed to stop the driving in the approaching direction to prevent interference.

Further, a stack height detecting sensor Sl7, which is a sheet position detecting means for detecting the upper surface of the stacked sheet bundle, is attached to the side surface of the reference wall 117.
When the sheet bundle is sequentially stacked on the stack tray 116 and the upper surface of the sheet bundle exceeds the sensor 17, the sensor 17 outputs a detection signal to the control device (CPU) 270 shown in FIG.

Here, the control device 270 is constructed as shown in FIG. 29, and the stack height detecting sensor S
When the detection signal from l7 is input, the stack tray elevating motor M13 is driven according to this signal to lower the stack tray 116, and the distance between the upper surface of the sheet bundle and the stack unit 13 is kept constant. There is.

Note that the control device 270 outputs a switching signal to the first deflector 3 and the second deflector 4 after the sheets have been stored in one sorter, and the sheets are stored in the other sorter. On the other hand, after driving the stack frame elevating motor Mll to move the stack unit 13 up and down toward one sorter, the first-out gripper 10 is moved through the first-out motor M7, and the conveyance gripper left-right movement motor M8 and the conveyance gripper are moved. Forward and backward motor M9
The transport gripper 12 is driven via the so as to sequentially stack the sheet bundle on the stack tray 116.

On the other hand, the pressing member 118 is for pressing the sheet bundle S on the stack tray 116 from above as shown in FIG. 30, and by pressing the sheet bundle S by the pressing member 118 in this way, Disturbance of the already stacked sheet bundle due to the sheet bundle stacked on the stack tray 116 can be prevented, and the sheet bundle stacked next on the stack tray 116 shifts in the sheet bundle when dropped and stacked. Can be prevented.

Next, the staple /
The operation of the stack device 205 in the sort mode will be described.

First, the grip / staple unit 9
Moves to a position (position indicated by a broken line in FIG. 2) corresponding to the sheet bundle removal of the upper bin module B _{1 and} stands by. At this time, the first-out gripper 10 stands by at the position shown in FIG. 15 with the grip portion 61 (see FIG. 21) opened so as not to obstruct the sheet on the bin when the bin in the bin module is moved up and down. ing. In the sort mode, the stapler 11 is not operated, so the stapler 1
1 moves to the front retracted position 11a indicated by the broken line in FIG.

On the other hand, as shown by the broken line in FIG. 15, the transport gripper 12 can grip the approximate center of the conveyed sheet bundle S in the arrow F direction, and is advanced by the advance gripper 10 in the arrow G direction. The gripping portion 61 is released at the position 12a where the front end of the sheet bundle S can be gripped, and stands by.

Next, the stack unit 13 moves to the position shown by the broken line in FIG. 2 and can receive the sheet bundle conveyed by the grip / staple unit 9. At this time, as shown in FIG. 25, the stack tray 116 moves to a position where the upper surface can receive the sheet bundle, and the reference wall 117 and the pressing member 118 move to a position corresponding to the stack tray 116.

As described above, when the sheet processing apparatus side is in the standby state, the original is fed, the image is formed, and the sheet is conveyed, the first sheet passes through the folding apparatus 204 as shown in FIG. And is conveyed from the carry-in port 215 to the upper side by the first deflector 3 and further leftward by the second deflector 4 and discharged onto the bin B ₁₁ by the discharge roller 8g.

Then, the paper discharge sensor Sl8 sets 1 in the bin B ₁₁ .
When it detects that the second sheet has been discharged, the bin will
The bin B ₁₂ shifts to the upper side of the bin and rises to the storage position. By repeating the above operation, the upper bin module B ₁
When the sheets of the same image are discharged to all the bins, the original is replaced and the image is formed on the second original.

In the bins of the upper bin module B ₁ , the lowermost bin (B _{16 in} FIG. 2) is at the sheet accommodating position, and the second sheet is accommodated in order from the lowermost bin. Repeat the above operation for all originals,
The operation of storing the sheets in the bin is completed. The sheets stacked on the bin are the reference rods 14a and 14b shown in FIG.
On the other hand, the alignment wall 15 is aligned by operating in the direction orthogonal to the sheet conveyance.

When the sorting and alignment are completed in this way, first, the first-out gripper 10 moves from the solid line position to the broken line position with the gripper portion 61 open in FIG. 16, and then nips the sheet bundle S.

Next, as shown in FIG. 13, the bin standing portion Bj
However, the sheet bundle can be conveyed by being opened by the solenoid SLl. At this time, the sheet bundle has both sides by the reference rods 14a and 14b (see FIG. 12) on the front side, the alignment rod 15 (see FIG. 12) and the guide member 53a (see FIG. 15) on the back side. It is regulated and is guided by the bin surface, the tilted bin standing portion Bj and the guide stay 53 in the downward direction, and the guide stay 52 in the upward direction, so that it can be conveyed to the conveyance gripper 12 side in FIG.

After that, the first-out gripper 10 holding the sheet bundle S moves from the two-dot chain line position shown in FIG. 18 to the solid line position, and then stops at the solid line position shown in FIG. 15, where the first-out gripper 10 and the transport gripper are arranged. The sheet bundle S between the sheets 12 is transferred. That is, the transport gripper 12 that has been waiting at the position indicated by the broken line in FIG. 15 first nips the substantially central portion of the sheet bundle, and then the first-out gripper 10 releases the nipping, and then from the position indicated by the solid line in FIG. Move to the position indicated by the chain double-dashed line and prepare for the next conveyance.

On the other hand, the transport gripper 12 is shown in FIG.
The sheet bundle S is conveyed rightward by being driven in the right direction of arrow G, and is stopped at an appropriate position according to the size. In this state, as shown in FIG. 28, the rear end of the sheet bundle S is dropped on the upper surface of the stack tray 116, the left side is regulated by the stacker reference wall 117, and the upper surface of the bundle is driven by a solenoid. The pressing member 118 is pressed.

From this state, the transport gripper 12 is opened and the leading end of the sheet bundle is also dropped onto the stack tray 116. At this time, the pressing member 118 has a function of preventing deviation in the falling bundle.

Next, when the second bundle of sheets is being conveyed, the conveyance gripper 12 grasps the approximate center of the sheet bundle,
The operation up to the point where the bundle is transferred between the grippers is the same as that of the first bundle, so only the subsequent operation will be described.

After the bundle is delivered, the transport gripper 12 moves by a predetermined amount in the direction of arrow F in FIG. At this time, the reference rod, the alignment wall, and the guide member 53a may escape so that the trailing edge of the sheet bundle is not regulated. Further, after the trailing edge of the sheet bundle is completely removed from these width regulating members, The transport gripper 12 may be moved in the arrow F direction. By this movement, when stacking the sheet bundle on the stack tray 116, it is possible to identify the sheet bundle from the first sheet bundle.

During the rightward conveyance by the conveyance gripper 12, as shown in FIG. 30, before the rear end of the sheet bundle S ₂ reaches a predetermined position, the central portion of the sheets comes first on the stack tray 116. It dropped on the top of ₁ ,
If the conveyance is continued as it is, the conveyed sheet bundle S ₂ may disturb the alignment of the already stacked sheet bundle S ₁ . On this occasion,
As shown in the figure, the stacking sheet S ₁
By pressing the upper surface of the sheet stack, it is possible to prevent the deviation of the already stacked sheet bundle S ₁ .

By the way, regarding the sheet bundle stacked on the stack tray 116, the uppermost surface thereof is always the reference wall 1.
It is detected by the stack height detection sensor Sl7 sensor 17 and the control device 270 gradually lowers the stack tray 1116 so that the distance between the upper grip / staple unit 9 and the uppermost stacking surface is always constant. I have to.

Regarding the sheet bundle on the stack tray 116, the sheet bundle can be arbitrarily taken out when the stack unit 13 is not in operation. Therefore, when the operator presses a take-out button (not shown), the stack unit 13 moves to the take-out position, and only the stack take-out cover can be opened and closed. Further, after taking out the sheet bundle, the cover is closed to continue. Processing becomes possible.

Next, the case of the staple sort mode will be described. Note that, here, the conveyance of the sheet and the sheet bundle is the same as that in the case of the sort mode described above, and therefore the description thereof will be omitted and the movement control of the stapler will be described.

First, the case of binding at one front position will be described. In this case, in the non-stapling mode, as shown in FIGS. 15 and 22, the stapler 11 at the retracted position 1la on the front side or the retracted position 11b on the rear side moves to the standby position 11c. As shown in FIG. 15, even when the stapler 11 is at the standby position 11c, the transport grippers 12 can stand by without interfering with each other.

After the stapler 11 performs the stapling operation on the sheet bundle conveyed by the first-out gripper 10, the stapler 11 moves to the front retracted position 1la, and then the sheet bundle is conveyed rightward by the conveying gripper 12. . When the trailing edge of the sheet bundle comes out of the moving area of the staple 11, the stapler 11 again returns to the standby position 1lc for binding one place.
Go to and wait for the next stack of sheets.

In the case of binding in the back one place, the binding is performed only on the back side of the paper size center.
On the contrary, the stapler reciprocates between the retracted position 11b on the back side and the binding position.

Next, the case of binding at two places will be described.

The two binding positions take various positions depending on the size in the width direction of the sheet bundle, but it is assumed that there is a size in which the two binding positions of the stapler positions 1ld and 1le shown in FIGS. 15 and 22 are binding positions. Also in this case, as shown in FIG.
Even if it is in lle, it does not interfere with the position of the transport gripper 12a.

At the time of standby for binding in two places, the stapler 1
1 moves from the retracted position 1la on the front side to two driving positions 1ld on the front side and stands by. At this time, the transport gripper 12 stands by at the position of the solid line 12b. Then, when the sheet bundle is conveyed by the first-out gripper 10, the first-out gripper 10 holds the sheet bundle and the stapler 1
When 1 is 1ld, staple one place on the front side.
Next, the stapler 11 moves to the position of 1 le and staples the two positions on the back side.

The stapler 11 moves from the position 1ld to 1le.
Immediately after moving to the position of
From the standby position of No. 12 to the holding position of 12a. Then, the transport gripper 12 holds the sheet bundle, while the first-out gripper 10 releases the sheet bundle. Stapler
After performing the second stapling operation at the position of 1le, it moves to the retracted position 11b on the back side.

When the trailing end of the first bundle of sheets passes through the stapler moving region, the stapler 11 moves from the retracted position 1lb to the staple position 1le on the inner side and receives the second bundle of sheets. This time, after hitting the back side of the two places first, it moves to the position ld in front. The transport gripper 12
Like the first bundle, hit the first place and staple the second place.
It waits at the position 12b until 1 is moved, then moves to 12a, waits for the retracting operation of the stapler 111 to the near side, and the bundle of sheets is conveyed. As mentioned above, 2
At the time of stapling, the processing time is shortened by alternating the retracted position of the stapler between the front side and the back side.

[0124]

As described above, according to the present invention, the folding portion is selectively folded by the folding means to have a predetermined size, and a folding pressure is applied again to the folded portion of the sheet to fold the sheet. You can fold the sheet without getting tired. The folding height can be reduced by folding the sheet in such a manner that the folding is not unfavorable, and the sheet can be stacked on the sheet tray in a stable state.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal configuration of an electrophotographic copying machine which is an example of an image forming apparatus to which the present invention can be applied.

FIG. 2 is a vertical sectional front view of a sheet processing apparatus provided in the electrophotographic copying machine.

FIG. 3 is a vertical sectional front view of a folding device provided in the sheet processing apparatus.

FIG. 4 is a diagram showing a folding operation in the C folding mode of the folding device.

FIG. 5 is a diagram showing a state in which a sheet folded in the C-folding mode is sent to a conveyance path.

FIG. 6 is a diagram showing a folding operation in a Z folding mode of the folding device.

FIG. 7 is a diagram showing a state in which a sheet folded in the Z-folding mode is sent to a conveyance path.

FIG. 8 is a perspective view of a bin module provided in the sheet processing apparatus.

FIG. 9 is a plan view of a matching wall driving unit provided in the bin module.

FIG. 10 is a side view of the matching wall driving unit.

FIG. 11 is a side view of the bottle module.

FIG. 12 is a plan view of the bin module.

FIG. 13 is a side view of the bin standing portion drive unit.

FIG. 14 is a plan view of the bin standing portion drive unit.

FIG. 15 shows a grip / provided on the sheet processing apparatus.
FIG. 3 is a plan view of the staple unit.

FIG. 16 is a side view of the grip / staple unit.

FIG. 17 is a plan view of a first-out gripper driving unit provided in the grip / staple unit.

FIG. 18 is a side view of the first-out gripper driving unit.

FIG. 19 is a plan view of a transport gripper driving unit provided in the grip / staple unit.

FIG. 20 is a side view of the transport gripper drive unit.

FIG. 21 is a side view of grip portions of the transport gripper driving unit and the first-out gripper driving unit.

FIG. 22 is a left side view of a staple unit driving portion provided in the grip / staple unit.

FIG. 23 is a plan view of the staple unit driving section.

FIG. 24 is a plan view of a stack unit provided in the grip / staple unit.

FIG. 25 is a front view of the stack unit.

FIG. 26 is a left side view of the drive unit of the stack unit.

FIG. 27 is a front view of a stack tray provided in the stack unit.

FIG. 28 is an operation view showing an effect of a stack pressing member provided in the stack unit.

FIG. 29 is a diagram showing a configuration of a control device provided in the sheet processing apparatus.

FIG. 30 is a view showing a state where the stack pressing member prevents the stack of stacked sheets from being displaced.

[Explanation of symbols]

203 sheet processing apparatus 240 conveying path 246 and 247 the pressure rollers 238, 239 folding roller pair S sheet _{B 11 ~B 1n, B 21 ~B} 2n bins

Claims (3)

[Claims] 1. A sheet processing apparatus in which an ejected sheet is selectively folded and then conveyed to a sheet tray, which is located upstream of the sheet tray and is bent at least once more than a predetermined time. Folding means for sizing, and pressurizing means provided in a transport passage for transporting the sheet of the predetermined size to the sheet tray, and applying a folding pressure to the folding portion of the sheet again. Sheet processing device. 2. The pressing means is constituted by a pair of rollers, and when the sheet is folded twice or more, the pressing means is arranged so that the leading end and the folded portion of the sheet simultaneously pass through the pressing means. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is provided in a substantially straight conveying path. 3. An image forming unit for forming an image on a sheet,
An image forming apparatus comprising: a sheet processing apparatus that performs post-processing of a sheet on which an image is formed by the image forming unit, wherein the sheet processing apparatus is the sheet processing apparatus according to claim 1 or 2. Image forming apparatus.