JP2022131163A - Sheet processing device and image forming system - Google Patents

Abstract

To provide a sheet processing device capable of switchback-conveying a folded sheet without buckling the sheet and capable of folding processing, and an image forming system including the same.SOLUTION: A sheet processing device controls to drive a folding roller pair 22 and a control stopper 26 so as to press a sheet that is nipped by the folding roller pair 22 and an end part of which is in contact with the control stopper 26 against a pressing guide member 30 after moving the pressing guide member 30 to a guide position when switchback-conveying the sheet that has been folded by the folding roller pair 22 while guiding by the pressing guide member 30.SELECTED DRAWING: Figure 13

Description

The present invention relates to, for example, a sheet processing apparatus for folding sheets sent from an image forming apparatus and an image forming system having the same.

2. Description of the Related Art Conventionally, there has been provided a sheet processing apparatus that folds a bundle of sheets into a booklet as post-processing of sheets discharged from image forming apparatuses such as copiers, printers, facsimiles, and multifunction devices thereof. For example, there is known a sheet processing apparatus that folds a sheet delivered from an image forming apparatus to a sheet stacker at a predetermined position with a veneer, pushes the sheet into the nip portion of a pair of folding rollers, and folds the sheet in half while being conveyed by the pair of folding rollers. there is

Some sheet processing apparatuses for folding a sheet not only fold the sheet in two, but also fold the sheet at two different locations, and fold the sheet so that one end of the sheet is inside the folded sheet. 2. Description of the Related Art There is a sheet processing apparatus that performs inward tri-fold processing. In such an apparatus, the sheet that has undergone the first folding process is switchback-conveyed and returned to the stacker, and the second folding process is performed on this sheet at a position different from that of the first folding process, so that the sheet is folded into three inwards. (Patent Document 1).

JP 2012-56674 A

In the folding process, when the sheet is conveyed switchback, if the edge of the sheet is curled or the like, the edge of the sheet may be turned up, and the sheet may not be returned to the stacker in an appropriate state. In order to prevent this, in Patent Document 1, as shown in FIG. 18A, a turn-up prevention member 201 is provided in a sheet path that is switchback-conveyed by a pair of rollers 200 so as to be swingable about a shaft 201a. By swinging the prevention member 201 , the edge of the sheet S conveyed in the switchback is guided by the turn-up prevention member 201 and led to the stacker 202 .

However, in the configuration described in Patent Document 1, one side of the sheet S is guided by the anti-turnover member 201, but there is nothing to guide the opposite side, and the sheet is conveyed in a free state. For this reason, as shown in FIG. 18B, the sheet conveyed by the switchback may be lifted from the anti-turnover member 201 and the edge of the sheet may directly hit the joint 203 between the anti-turnover member 201 and the stacker 202 . In this case, the leading edge of the sheet S guided by the anti-turnover member 201 contacts the stacker 202 at a large angle (close to a right angle). In addition, the sheet S may be buckled, or the sheet S may be turned up, and it may not be possible to carry out switchback conveyance accurately.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet processing apparatus capable of performing a folding process by switchback-conveying a folded sheet without buckling it, and an image processing apparatus having the same. It provides a forming system.

A representative configuration according to the present invention for achieving the above object is to perform a first folding process on the sheet, and then fold the second folding line at a position different from the crease formed by the first folding process. In a sheet processing apparatus that folds a sheet so that one end of the sheet folded by the first folding process is inside the folded sheet, the sheet is transported in a predetermined transport direction. a conveying path having a guide surface for guiding; a first direction in which the sheet conveyed to the conveying path is nipped by a nip portion and rotated to pull in the sheet for folding; a rotating body pair capable of conveying the sheet in a second direction by switching back in a direction opposite to the direction in which the sheet was pulled in; a position adjusting unit capable of moving in the conveying direction and a direction opposite to the conveying direction to adjust the position of the sheet; and a standby position that does not act on the sheet conveyed on the conveying path, and a sheet folded by the pair of rotating bodies and conveyed in the second direction so as to change the direction of the sheet toward the conveying direction. a direction changing member movable to a guide position for guiding; and a control section for driving and controlling the rotating body pair, the position adjusting means, and the direction changing member, wherein the control section is configured to fold by the rotating body pair. When the sheet subjected to the processing is switched back, after the direction changing member is moved to the guide position, the sheet nipped by the pair of rotating bodies and whose end portion is in contact with the contact portion is returned. The pair of rotating bodies, the position adjusting means, and the direction changing member are driven and controlled so as to press against the direction changing member.

In the present invention, when the folded sheet is returned to the conveying path, the other end of the sheet is guided to the sheet pressed against the direction changing member by pressing the sheet against the direction changing member. is pressed against the direction changing member and conveyed. Therefore, the sheet is prevented from floating from the direction changing member, and the sheet is conveyed switchback without buckling.

FIG. 2 is an explanatory diagram of the overall configuration of the image forming system of the present embodiment; FIG. 1 is an explanatory diagram of the overall configuration of a sheet processing apparatus in an image forming system; Sectional view showing a folding device of the sheet processing device (a) is a cross-sectional view showing a gripping state of the grip means, and (b) is a perspective view thereof. (a) is a cross-sectional view showing the grip release state of the grip means, and (b) is a perspective view thereof. Plan view showing the sheet folding device Block diagram of folding control configuration Flowchart showing procedure for inward tri-folding Flowchart showing procedure for inward tri-folding (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. (a) and (b) are cross-sectional explanatory diagrams of the operation of folding the sheet in three. Sectional view of a sheet processing apparatus provided with a pair of folding rollers having a small diameter portion (a) (b) (c) Explanatory diagrams of conventional technology

[First Embodiment]
Next, a sheet processing apparatus according to a preferred embodiment of the present invention and an image forming system having the same will be described with reference to the drawings. FIG. 1 schematically shows the overall configuration of an image forming system equipped with a sheet processing apparatus according to an embodiment of the invention. As shown in the figure, the image forming system 100 includes an image forming apparatus A and a sheet processing apparatus B provided side by side.

<Image forming apparatus>
The image forming apparatus A is composed of an image forming unit A1, a scanner unit A2 and a feeder unit A3. The image forming unit A1 includes a feeding section 2, an image forming section 3, a discharging section 4, and a data processing section 5 inside an apparatus housing 1. As shown in FIG.

The feeding unit 2 is composed of a plurality of cassette mechanisms 2a, 2b, and 2c for accommodating image forming sheets of different sizes, respectively, and delivers sheets of a size specified by a main control unit (not shown) to the feeding path 2f. Each of the cassette mechanisms 2a, 2b, and 2c is installed detachably from the feeding section 2, and incorporates a separating mechanism for separating the sheets one by one and a feeding mechanism for delivering the sheets. The feeding path 2f is provided with conveying rollers for feeding the sheets supplied from the respective cassette mechanisms 2a, 2b, and 2c to the downstream side, and a pair of registration rollers for aligning the leading edges of the sheets at the end of the path. ing.

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

The image forming unit 3 is configured using an electrophotographic method in this embodiment, and includes a rotating photosensitive drum 3a, a light emitting device 3b for emitting an optical beam, a developing device 3c, and a cleaner ( not shown). The illustrated one is a monochrome printing mechanism, in which a photosensitive drum 3a whose circumferential surface is uniformly charged is irradiated with light according to an image signal from a light emitting device 3b to optically form a latent image, which is then developed. A toner image is formed by depositing toner with the device 3c.

The sheet is sent to the image forming section 3 through the feeding path 2f in time with the timing of image formation on the photosensitive drum 3a, and the toner image formed on the photosensitive drum 3a is transferred onto the sheet by applying a transfer bias from the transfer charger 3d. to be transcribed. The sheet on which the toner image has been transferred is heated and pressurized when passing through the fixing device 6 so that the toner image is fixed. .

The scanner unit A2 includes a platen 7a on which an image original is placed, a carriage 7b that reciprocates along the platen 7a, photoelectric conversion means 7c, and photoelectric conversion of light reflected from the original on the platen 7a by the carriage 7b. and a reducing optical system 7d guiding to means 7c. The photoelectric conversion means 7c photoelectrically converts the optical output from the reduction optical system 7d into image data, and outputs the image data to the image forming section 3 as an electric signal.

The scanner unit A2 also has a traveling platen 7e for reading the sheet fed from the feeder unit A3. The feeder unit A3 has a feed tray 8a for stacking document sheets, a feed path 8b for guiding the document sheets sent from the feed tray 8a to the traveling platen 7e, and accommodates the document sheets passing through the traveling platen 7e. It is composed of the discharge tray 8c. A document sheet from the feed tray 8a is read by the carriage 7b and the reduction optical system 7d when passing the traveling platen 7e.

<Sheet processing device>
Next, the overall configuration of the sheet processing apparatus B for post-processing sheets sent from the image forming apparatus A will be described.

FIG. 2 is an explanatory diagram of the configuration of the sheet processing apparatus B according to this embodiment. The sheet processing apparatus B includes an apparatus housing 11 provided with a loading port 10 for introducing sheets from the image forming apparatus A. As shown in FIG. The apparatus housing 11 is arranged in alignment with the housing 1 of the image forming apparatus A so that the inlet 10 communicates with the outlet 4b of the image forming apparatus A. As shown in FIG.

The sheet processing apparatus B includes a sheet carry-in path 12 for conveying sheets introduced from a carry-in port 10, a first discharge path 13a, a second discharge path 13b, and a third discharge path 13c branched from the sheet carry-in path 12, It comprises a first path switching means 14a and a second path switching means 14b. The first path switching means 14a and the second path switching means 14b are each composed of a flapper guide for changing the transport direction of the sheet transported on the sheet carry-in path 12. As shown in FIG.

The first path switching means 14a guides the sheet from the carry-in port 10 in the direction of the first discharge path 13a that conveys the sheet in the horizontal direction and the second discharge path 13b that conveys it downward by the driving means (not shown). The mode is switched to the mode in which the sheet is guided to the third discharge path 13c that conveys upward. The first discharge path 13a and the second discharge path 13b are communicated so that the sheet once introduced into the first discharge path 13a can be reversed in the conveying direction and conveyed back to the second discharge path 13b. is doing.

The second path switching means 14b is arranged on the downstream side of the first path switching means 14a with respect to the conveying direction of the sheet conveyed through the sheet carry-in path 12. As shown in FIG. The second path switching means 14b has a mode in which the sheet that has passed through the first path switching means 14a is introduced into the first discharge path 13a by driving means (not shown), and a mode in which the sheet once introduced into the first discharge path 13a is transferred to the second mode. 2, the mode is switched back to the discharge path 13b.

The sheet processing apparatus B includes a first processing section B1, a second processing section B2, and a third processing section B3 that perform different post-processing. Further, a punch unit 15 for punching holes in the sheet that has been carried in is arranged in the sheet carrying-in path 12 .

The first processing unit B1 accumulates a plurality of sheets discharged from the discharge port 16a at the downstream end of the first discharge path 13a in the conveying direction of the sheets conveyed on the sheet conveying path 12, aligns them, and performs binding processing. , and discharges them onto a stacking tray 16b provided outside the apparatus housing 11. FIG. The first processing section B1 also includes a sheet conveying device 16c that conveys sheets or a sheet bundle, and a binding processing unit 16d that binds the sheet bundle. A discharge roller pair 16e is provided at the downstream end of the first discharge path 13a for discharging the sheet from the discharge port 16a and for switchback conveying from the first discharge path 13a to the second discharge path 13b.

The second processing section B2 folds the sheet or a plurality of sheets that are switchback-conveyed from the second discharge path 13b into a sheet bundle, or performs folding processing after binding the sheet bundle. Department. As will be described later, the second processing section B2 includes a folding processing device F that folds the sheet or sheet bundle that is carried in, and a folding processing device that folds the sheet conveyed to the second discharge path 13b along the sheet conveying direction. A binding processing unit 17a is provided immediately upstream of F and binds the sheet bundle. The folded sheet or sheet bundle is discharged onto a stacking tray 17c provided outside the apparatus housing 11 by a discharge roller pair 17b.

The third processing section B3 classifies the sheets sent from the third discharge path 13c into a group in which the sheets are stacked with a predetermined amount of offset in the sheet width direction orthogonal to the conveying direction, and a group in which the sheets are stacked without being offset. Perform jog sorting. The jog-sorted sheets are discharged to a stacking tray 18 provided outside the device housing 11, and offset sheet bundles and non-offset sheet bundles are stacked.

FIG. 3 schematically shows the overall configuration of the second processing section B2. As described above, the second processing unit B2 includes the folding processing device F that folds the sheets carried in from the second discharge path 13b or the sheet bundle that is stacked and collated into two, and and a binding processing unit 17a for binding the sheet bundle. The illustrated binding processing unit 17a is a stapler device that binds a sheet bundle by driving staples.

A sheet conveying path 20 is connected to the second discharge path 13b in order to carry the sheet into the folding device F. As shown in FIG. An intermediate tray 21 forming a part of the sheet transport path 20 positions the sheet to be folded on the downstream side of the sheet transport path 20 with respect to the transport direction of the sheet transported to the intermediate tray 21 from the second discharge path 13b. It is provided for loading and unloading. Immediately upstream of the intermediate tray 21, the binding processing unit 17a and its staple receiving portion 17d are provided at opposing positions with the sheet conveying path 20 interposed therebetween.

<Folding device>
On one side of the intermediate tray 21, a pair of folding rollers 22 as a pair of folding rollers are arranged so as to face one side of the sheet or sheet bundle stacked on the intermediate tray 21. As shown in FIG. The folding roller pair 22 is composed of a pair of folding rollers 22a and 22b whose roller surfaces are brought into pressure contact with each other, and a nip portion 22c, which is the pressure contact portion, is arranged facing the intermediate tray 21. As shown in FIG. The folding rollers 22a and 22b are arranged so that the intervals between the intermediate tray 21 and the intermediate tray 21 are substantially equal on the upstream side and the downstream side along the conveying direction of the sheet conveyed from the upper upstream side to the lower downstream side on the intermediate tray 21. are juxtaposed. In the present invention, the rotating portion of the pair of folding rotating members is not limited to the folding rollers 22a and 22b of the present embodiment, and can be configured by a rotating belt or the like. Further, the folding roller pair 22 can be configured by continuously arranging a plurality of folding rollers (rotating bodies) in series along the axial direction of each of the folding rollers 22a and 22b.

A folding blade 23 as a projecting member is arranged on the opposite side of the folding roller pair 22 with the intermediate tray 21 interposed therebetween. The folding blade 23 is carried by the blade carrier 24 with its tip facing the nip portion 22 c of the folding roller pair 22 . The blade carrier 24 is moved in a direction substantially perpendicular to the intermediate tray 21 by a moving means such as a cam member, i. It is set up so that it can run.

3, i.e., in the axial direction of the folding roller, on both sides of the blade carrier 24, cam members 25 each comprising a pair of mirror-symmetrical eccentric cams (only one of them is shown in the figure). are provided at opposing positions. The cam member 25 is rotated around a rotating shaft 25a provided at an eccentric position thereof by driving means such as a driving motor. A cam groove 25b is formed in the cam member 25 along its outer peripheral edge.

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

The blade carrier 24 reciprocates toward or away from the intermediate tray 21 when the cam member 25 is rotated by the drive motor. As a result, as shown in FIG. The folding blade 23 can be linearly moved back and forth between the protruding positions along the protruding path connecting the two positions.

At the lower end of the intermediate tray 21, a regulating stopper 26 serving as position adjusting means for adjusting and positioning the sheet in the sheet conveying path by contacting and regulating the tip of the conveyed sheet in the conveying direction is arranged. It is The regulation stopper 26 is provided so as to be movable up and down along the intermediate tray 21 by a sheet lifting mechanism 27 .

The sheet lifting mechanism 27 of this embodiment is designed to move the blade carrier 24 at the initial position where the tip of the folding blade 23 does not enter the sheet conveying path formed by the intermediate tray 21 on the back side of the intermediate tray 21 . It is a conveyor belt mechanism comprising a pair of pulleys 27a and 27b arranged below the intermediate tray 21 near its upper and lower ends, and a transmission belt 27c wound around both pulleys. The regulation stopper 26 is fixed on the transmission belt 27c. By rotating the pulley 27a or 27b on the drive side by a drive means such as a drive motor, the regulation stopper 26 moves up and down between the lower end position shown in FIG. A sheet or stack of sheets can be moved along and positioned at the desired height.

The restricting stopper 26 can move up and down along the intermediate tray 21 as described above. It's becoming The gripping means 50 grips the sheet conveyed to the intermediate tray 21 and ensures the movement of the sheet along with the movement of the regulation stopper 26 .

Next, the configuration of the grip means 50 will be described with reference to FIGS. 4 and 5. FIG. 4(a) is a cross-sectional view of a state in which the grip means 50 can grip the sheet, and FIG. 4(b) is a perspective view thereof. FIG. 5(a) is a cross-sectional view of a state in which the grip means 50 has released the grip of the sheet, and FIG. 5(b) is a perspective view thereof.

As shown in FIG. 4, the grip means 50 are attached to the regulation stopper 26. As shown in FIG. The regulation stopper 26 is provided with a contact portion 26b on a base portion 26a which is movable along the guide surface 21a of the intermediate tray 21 by driving transmission from the transmission belt 27c. The contact portion 26b positions the sheet by contacting the lower end of the sheet conveyed to the intermediate tray 21, and adjusts the position of the contact portion 26b during the folding process to move the sheet to the folding position. and move. A standing portion 26c is formed continuously on the contact portion 26b and bent at a right angle so that the sheet in contact with the contact portion 26b can be accommodated so as not to fall off.

The gripping means 50 is attached to the base portion 26a and moves integrally with the base portion 26a as it moves along the guide surface 21a. The gripping means 50 is attached to the base portion 26a so as to be slidable in the direction along the thickness of the sheet conveyed to the intermediate tray 21, and the standing portion 50b is integrated with the supporting portion 50a. A holding portion 50c is formed on the inner surface side of the standing portion 50b. Further, a facing portion 50d is provided integrally with the base portion 26a at a position facing the gripping portion 50c with the sheet conveying path to the intermediate tray 21 interposed therebetween.

An elastic member (not shown) such as a spring is attached between the base portion 26a and the support portion 50a, and the standing portion 50b is always urged toward the facing portion 50d. As a result, the gripping portion 50c is normally pressed against the facing portion 50d to grip the sheet conveyed to the intermediate tray 21 (see FIGS. 4A and 4B). ).

As shown in FIG. 5A, the base portion 26a is provided with a grip cam 50e engaged with the support portion 50a and a cam motor (not shown) for rotating the grip cam 50e. The grip cam 50e has a large-diameter portion and a small-diameter portion. When the grip cam 50e rotates, the support portion 50a engaged therewith slides in the direction of the arrow shown in FIG. The grasping portion 50c abuts and separates from it. This makes it possible to control the gripping means between a gripping state and a grip release state in which the grip is released.

The support portion 50a is disposed below the contact portion 26b of the regulating stopper 26, i.e., at a position far from the folding roller pair 22. A sheet positioned in contact with the contact portion 26b can be gripped. A grip portion 50c, which is a grip portion for gripping the sheet, is provided above the contact portion 26b, that is, at a position close to the folding roller pair 22. As shown in FIG. Therefore, it is possible to reliably grip the sheet whose end is in contact with the contact portion 26b.

Further, the folding device F of this embodiment further includes a sheet side alignment mechanism for aligning and aligning the sides of the sheets carried into the intermediate tray 21 . As shown in FIG. 6, the sheet side aligning mechanism has a pair of sheet side portions symmetrically arranged on both sides of the intermediate tray 21 in the sheet width direction (the direction along the sheet surface orthogonal to the sheet conveying direction). Alignment members 28a and 28b are provided. 6 is a schematic plan view of the folding device F viewed from above. The sheet side aligning members 28a and 28b are movably held so as to move toward and away from each other in the sheet width direction. By moving the sheet side aligning members 28a and 28b, the sheet is aligned in the width direction with respect to the sheet conveyed to the intermediate tray 21 and the leading edge of the sheet abutting the regulation stopper 26. FIG.

<Control section>
Next, the control configuration of the drive system when folding the sheet will be described. As shown in the block diagram of FIG. 7, the control unit 60 receives detection signals from various detection sensors and various processing signals, and controls driving of various drive motors and the like according to the input signals. For example, a regulation stopper HP sensor 61 that detects whether the regulation stopper 26 is at the home position, a folding blade HP sensor 62 that detects whether the folding blade 23 is at the home position, and a pressing guide member 30 (see FIG. 10) is at the home position.

Then, the control unit 60 operates the regulating stopper motor 65 and the blade carrier 24 for driving the sheet lifting mechanism 27 that lifts and lowers the regulating stopper 26 in accordance with the procedures of the flow charts shown in FIGS. 8 and 9 according to the input signal. A cam motor 66 that drives the cam member 25 for folding and a folding roller motor 67 that drives and rotates the pair of folding rollers 22 are driven and controlled. Further, the control unit 60 drives and rotates an ejection roller motor 68 that drives and rotates the ejection roller pair 17b serving as sheet conveying means, a pressing guide motor 69 that operates the pressing guide member 30, and a grip cam 50e of the gripping means 50. It drives and controls the grip cam motor 70 .

The control unit 60 may be provided directly in the sheet processing apparatus B, or the control unit 60 may be provided in the main body of the image forming apparatus, and the control unit 60 may drive the sheet processing apparatus B coupled with the image forming apparatus A. may be configured to control the

<Tri-folding operation>
8 and 9 are flow charts showing the operation procedure of each member when the sheet conveyed to the intermediate tray 21 is folded inwards by the folding device F. FIG. It should be noted that the in-three-folding process means that a sheet is folded in two by the first folding process, and the second folding process is performed on the sheet at a position different from the first folding position. This is a process of folding in three such that one end of the sheet folded by the second folding process is folded inside the sheet to be folded by the second folding process.

In the folding processing apparatus F of the present embodiment, when performing the inward three-folding processing, the sheet folded in half by the first folding processing is guided by the pressing guide member 30 and returned to the intermediate tray 21. By pressing the sheet against the pressing guide member 30, the sheet is reliably conveyed in the switchback without being buckled.

8 and 9 and the movement of each part along the flow of the sheets S when the inward three-folding process is performed by the folding processing apparatus F of the present embodiment will be described below. Description will be made with reference to schematic cross-sectional views of FIGS. 10 to 16 .

When the folding process is started, the regulation stopper 26 moves to the "first folding position" (S1). The first folding position is a position where the first folding position of the sheet S faces the folding blade 23 when the leading edge E1 of the sheet conveyed to the intermediate tray 21 abuts against the contact portion 26b. be. At this time, the gripping cam 50e of the gripping means 50 rotates to release the gripping state, that is, the gripping portion 50c is separated from the facing portion 50d so that the restricting stopper 26 can receive the sheet.

As shown in FIG. 10A, the intermediate tray 21 of this embodiment is formed to be inclined with respect to the vertical direction, and when the sheet S is conveyed to the intermediate tray 21 (S2), the sheet S is While being guided by the guide surface 21a forming the intermediate tray 21, the sheet is transported so that the leading end E1 of the sheet falls and the trailing end E2 of the sheet rises. Stops after being hit.

The folding blade 23 is arranged at a position to project the sheet S toward the folding roller pair 22 from the side of the guide surface 21 a of the intermediate tray 21 . In other words, the guide surface 21a of the intermediate tray 21 and the pair of folding rollers 22 are arranged at corresponding positions with the sheet S interposed therebetween.

When the folding process is executed, as shown in FIG. 10B, the cam motor 66 is driven to move the blade carrier 24 toward the pair of folding rollers 22, and the folding blade 23 reaches the first folding position of the sheet S. and protrude into the nip portion 22c (S3). At the same time, the folding roller motor 67 and the discharging roller motor 68 are driven to rotate the folding roller pair 22 and the discharging roller pair 17b forward (S4). When a pulse motor is used for each of the motors, when the motor is driven, the number of driving pulses is counted by a counter. When a DC motor is used as each motor, a sensor reads the slits of a code wheel (slit plate) mounted on the rotating shaft of the motor, and the number of slits is counted by a counter. The sheet conveying amount, the sheet protrusion amount, and the like can be detected from the count value.

When the sheet S protruded by the folding blade 23 reaches the nip portion 22c by the folding roller pair 22 and is nipped (S5), the regulation stopper 26 starts moving to the "sheet receiving position" (S6). ). The sheet receiving position is set when the folding-processed sheet that has undergone the first folding process by the folding roller pair 22 is switched back and transported to the intermediate tray 21 by the reverse rotation of the folding roller pair 22, and the transport of the sheet stops. This is the position where the sheet end E1 on the side far from the double folding position abuts the abutment portion 26b of the regulation stopper 26. As shown in FIG.

As described above, when the regulation stopper 26 is moved toward the sheet during the folding operation, if the regulation stopper 26 comes into contact with the edge of the sheet projected by the folding blade 23 , the folding blade 23 may There is a risk that the folding position of the sheet may be misaligned. However, in this embodiment, after the sheet S is nipped by the nip portion 22c as described above, the regulating stopper 26 is moved to the receiving position. Therefore, the folding position of the sheet does not shift.

Note that the movement of the regulation stopper 26 may be started before the sheet reaches the nip portion 22 c of the folding roller pair 22 . In that case, it is necessary to move the regulating stopper 26 at a sheet conveying speed slower than the speed at which the folding blade 23 protrudes the sheet so that the moving regulating stopper 26 does not come into contact with the edge of the sheet protruding into the nip portion 22c. There is

When the folding blade 23 projecting the sheet S projects the first folding portion of the sheet S to the nip portion 22c of the folding roller pair 22 by a predetermined amount, the traveling direction of the folding blade 23 is reversed by the rotation of the cam member 25 to move in the returning direction. to return to the home position (S7).

Due to the projection of the folding blade 23, the sheet S projected into the nip portion 22c where the first roller surfaces 22a2 and 22b2 of the folding roller pair 22 are pressed against each other as shown in FIG. While being pressed, the sheet is folded with a predetermined pressing force, and is conveyed as it is by the pair of discharge rollers 17b that constitute the sheet conveying means together with the pair of folding rollers 22. As shown in FIG.

Next, in order to perform the second folding process, as shown in FIG. 11B, sheet conveyance is stopped when the trailing edge E2 of the sheet that has undergone the first folding process reaches a predetermined position (S8). , S9). The predetermined position is a position where the trailing edge E2 of the sheet S closer to the fold is conveyed into the sheet conveying path formed by the intermediate tray 21 .

Above the folding blade 23, an L-shaped pressing guide member 30, which is a direction changing member, is arranged so as to be rotatable about a rotating shaft 30a. The pressing guide member 30 changes the direction of the conveyed sheet in order to return the sheet folded by the pair of folding rollers 22 and conveyed in a switchback to the intermediate tray 21. and a waiting position (see FIG. 11(b)) that does not affect the change of the sheet conveying direction, and a guide position (see FIG. 12(a) that guides to change the direction of the conveyed sheet). ) and can be moved to.

When the trailing edge E2 of the sheet reaches the predetermined position, the sheet conveying is stopped until the trailing edge E2 of the sheet is below the rotation shaft 30a (in the direction of the intermediate tray 21 where the leading edge E1 of the sheet is located). is preferably carried. From this state, the folding roller pair 22 and the discharge roller pair 17b are reversely driven to execute the switchback conveying process. The trailing edge E2 of the sheet becomes an edge portion (hereinafter referred to as a "folding edge portion") that is folded inside the sheet that is folded in the second folding process when the sheet is folded in three.

Then, when the switchback transport process is performed, the L-shaped pressing guide member 30 (see FIG. 11(b)) located at the home position (standby position) is moved as shown in FIG. 12(a). It is rotated about the rotation shaft 30a and moved to the switchback guide position (S10). Due to the rotation of the guide member 30, the folding end E2 is pushed downward (in the direction of the intermediate tray 21 where the sheet leading edge E1 is located). In this state, when the folding roller pair 22 and the discharge roller pair 17b are reversely driven (S11), the folded edge E2 of the sheet is guided by the guide surface of the pressing guide member 30 and conveyed to the intermediate tray 21. FIG.

At this time, as shown in FIG. 12A, the surface of the sheet S opposite to the surface guided by the pressing guide member 30 does not have a guiding member. There is a case where the folding end E2 is lifted from the guide surface of the guide member 30 and hits the intermediate tray 21 directly. In that case, the angle between the sheet S and the guide surface 21a when the folding end E2 contacts the guide surface 21a of the intermediate tray 21 increases, and the sheet may buckle.

Therefore, in this embodiment, as shown in FIG. 12(b), the sheet is gripped by the gripping means 50 (S11) before the sheet is switchback-conveyed. It is moved to the "sheet pressing position" positioned upward by a fixed amount (S12). This sheet pressing position is closer to the pressing guide member 30 than the sheet receiving position, and as shown in FIG. By moving the regulating stopper 26 upward while in contact with the pressure guide member 30, the sheet S between the nip portion 22c and the contact portion 26b is bent, and the bent sheet S is pressed against the guide surface of the pressing guide member 30. is. As a result, the sheet piece on the side of the folded end E2 is pressed against the guide surface of the pressing guide member 30, and is prevented from lifting from the guide surface.

Even if the sheet end E1 is pushed up by the regulating stopper 26 so as to bend the sheet as described above, the sheet end E1 is gripped by the grip means 50, so that the end E1 does not buckle. Also, the gripped sheet can be pressed against the pressing guide member 30 more reliably.

In the above state, the folding roller pair 22 and the discharge roller pair 17b are reversely driven to convey the sheet switchback (S13), and the regulation stopper 26 is lowered according to the speed and moved to the "reversal position" (S14). . As a result, as shown in FIG. 13B, the sheet S conveyed by the switchback is guided by the guide surface of the pressing guide member 30 on one side of the sheet piece on the side of the folding end E2, and on the other side. The surface is conveyed so as to be guided by the bent sheet piece between the nip portion 22c and the contact portion 26b. Therefore, the sheet piece on the side of the folding end E2 is not lifted from the guide surface of the pressing guide member 30, and the sheet is conveyed to the intermediate tray 21 without buckling.

The sheet whose folding end E2 is guided to the intermediate tray 21 as described above descends as the regulation stopper 26 gripping the sheet end E1 moves to the "reversal position". The reversing position is a position where the sheet is moved to a position where the pressing guide member 30 can rotate without interfering with the sheet S, as shown in FIG. 14(a). The sheet conveying amount to the reversing position is determined according to the sheet size and the folding position.

When the sheet that has passed through the nip portion 22c of the folding roller pair 22 is returned to the reversing position of the intermediate tray 21 by free fall, the sheet that has been folded in two has a sheet edge E2 closer to the fold. Since it has a shape resembling a barb of a fish hook, there is a risk that it will become a transport load and not move smoothly. However, in this embodiment, since the regulation stopper 26 is moved while gripping the sheet S as described above, the sheet is reliably conveyed to the reversing position even if there is a conveying load on the sheet.

Next, after the regulation stopper 26 moves to the reversing position, as shown in FIG. 14B, the sheet gripping by the grip means is released (S15), and the pressing guide member 30 is returned to the standby position (S16). By releasing the sheet grip as described above, even if the sheet registration is lost when the sheet is pulled back, the sheet comes to abut against the contact portion 26b due to its own weight, and the sheet end registration is corrected. is done.

After the grip is temporarily released as described above, the sheet is gripped by the grip means 50 (S17), and the regulation stopper 26 is moved to the "second folding position" (S18). The second folding position is a position where the second folding position of the sheet conveyed by movement of the regulation stopper 26 faces the folding blade 23 (see FIG. 15A). When the regulation stopper 26 is lifted while the sheet S abuts against the contact portion 26b, the sheet may bounce at the moment the regulation stopper 26 stops and the registration may be lost. Since it is moved to the second folding processing position while being gripped, there is no fear that the registration will be lost.

In this embodiment, the sheet is gripped before the regulation stopper 26 is moved to the second folding position, but the same effect can be obtained by gripping the sheet while the regulation stopper 26 is being raised. be able to.

After the regulating stopper 26 moves to the second folding position, the sheet gripping by the gripping means 50 is released (S19), and the cam motor 66 is driven to operate the folding blade 23 again, as shown in FIG. 15(b). Then, the sheet S is protruded to the nip portion of the folding roller pair 22 (S20).

In synchronization with the driving of the cam motor 66, the folding roller motor 67 and the discharge roller motor 68 are driven forward (S21). As a result, the sheet S sent to the folding roller pair 22 by the protrusion of the folding blade 23 is folded at the folding end E2 by the second folding process, as shown in FIGS. 16A and 16B. Folding processing is performed in a state in which the sheet is folded inside.

Then, the sheet S folded in three in the manner described above is discharged to the stacking tray 17c, and the folding process is completed (S22, S23).

As described above, in the present embodiment, when a folded sheet is switchback-conveyed, after the pressing guide member 30 is moved to the guide position, the folding roller pair nips and the sheet end portion is moved to the guide position. By pressing the sheet contacting the regulating stopper 26 against the guide surface of the pressing guide member 30, the sheet piece on the folding end E2 side can be guided to prevent the sheet from buckling. is.

[Second embodiment]
In the above-described embodiment, in order to bend the sheet nipped by the pair of folding rollers 22 and in contact with the contact portion 26b of the regulation stopper 26 and press it against the guide surface of the pressing guide member 30, the regulation stopper 26 is " An example of moving from the "sheet receiving position" to the "sheet pressing position" approaching the pressing guide member 30 is shown. However, the structure for bending the sheet may be a structure other than moving the regulation stopper 26 closer to the pressing guide member 30 .

For example, a speed difference is provided between the sheet conveying speed by the pair of folding rollers 22 and the sheet descending speed by the regulation stopper 26 when the sheet is switchback conveyed. Specifically, when the sheet that has undergone the first folding process is switchback-conveyed, the speed of the folding roller pair 22 is faster than the speed at which the regulation stopper 26 in the "sheet receiving position" is moved downward to the "reverse position". Set the switchback conveying speed of the sheet faster. As a result, the sheet conveyed by the switchback is bent between the nip portion 22c of the folding roller pair 22 and the contact portion 26b of the regulation stopper 26, and the bent sheet is pressed against the guide surface of the pressing guide member 30. Become.

By appropriately setting the speed difference according to the sheet size, the bent sheet can be made to function as a guide member, and the same effect as the above-described embodiment can be obtained.

In addition to the configuration in which the speed difference is provided, for example, a configuration may be employed in which the sheet conveyance start timing by the reverse rotation of the folding roller pair 22 and the downward movement start timing by the regulation stopper 26 are different when the sheet is switchback conveyed. . Specifically, when the sheet that has been subjected to the folding process is switchback-conveyed, after the switchback conveyance of the sheet by the pair of folding rollers 22 is started, the downward movement of the regulation stopper 26 is started after a lapse of a predetermined time. do.

If the regulation stopper 26 is stopped when the folding roller pair switches back and conveys the sheet, the sheet bends between the nip portion 22 c of the folding roller pair 22 and the contact portion 26 b of the regulation stopper 26 . Therefore, by starting the downward movement of the regulation stopper 26 when the bent sheet is pressed against the guide surface of the pressing guide member 30, the sheet is conveyed switchback while being pressed against the pressing guide member 30. It is possible to obtain the same effects as those of the above-described embodiment.

[Third Embodiment]
In the above-described embodiment, an example of performing folding processing on one sheet has been shown, but it is also possible to convey a plurality of sheets to the intermediate tray 21 and fold the plurality of sheets collectively. In that case, the greater the number of sheets, the greater the force required to bend the sheets.

Therefore, as in the above-described second embodiment, in the configuration in which a difference in speed is provided between the sheet conveying speed by the folding roller pair 22 and the sheet descending speed by the regulation stopper 26 when the sheets are switchback conveyed, the number of sheets increases. When the number of sheets is equal to or greater than the predetermined number, the speed difference between the sheet conveying speed by the folding roller pair 22 and the downward movement speed of the regulation stopper 26 is set larger than when the number of sheets is less than the predetermined number. As a result, when the number of sheets increases, the force for bending the sheets can be increased, and the sheets can be accurately pressed against the pressing guide member 30 .

Similarly, since a sheet with a large basis weight is stiffer than a sheet with a small basis weight, the state is the same as when the number of sheets is large. Therefore, as in the case of a large number of sheets, in the case of sheets with a basis weight greater than a predetermined value, the speed difference should be set to be greater than in the case of sheets with a basis weight less than the predetermined value.

The same applies to the configuration in which the downward movement of the regulation stopper 26 is started after a predetermined period of time has passed after the start of sheet conveyance by the pair of folding rollers 22 for switchback conveyance. When the predetermined time is set long, the force of pressing the bent sheet against the pressing guide member 30 increases. Therefore, when the number of sheets is a predetermined number or more, the predetermined time is set longer than when the number of sheets is less than the predetermined number, or when the basis weight of the sheet is a predetermined value or more, it is set longer than when it is less than the predetermined value. can be accurately pressed against the pressing guide member 30.

It should be noted that the number of sheets and basis weight can be determined by a signal from sheet determination means obtained by inputting from an input unit such as an operation panel.

[Fourth Embodiment]
In the above-described embodiment, the folding roller pair 22 is composed of a circular roller pair, and the folding roller pair 22 has a function of folding the sheet and a function of switchback conveying the sheet. However, the means for folding the sheets and the means for switchback-conveying the sheets may be configured separately.

For example, in the sheet folding apparatus shown in FIG. 17, each of the folding rollers 22a and 22b of the folding roller pair 22 has a circumferential surface with a constant radius R1 around the rotation axis of each of the rotation shafts 22a1 and 22b1. 1 roller surface (first peripheral surface) 22a2, 22b2 and second roller surface (second peripheral surface) 22a3, 22b3 whose distance from the rotation axis of the rotation shaft is smaller than the radius R1 of the first roller surface and rollers. In this embodiment, the first roller surfaces 22a2 and 22b2 are made of a rubber material or the like having a relatively high coefficient of friction, similar to the roller surfaces of rollers used for normal sheet conveyance. are made of a plastic resin material or the like whose coefficient of friction is smaller than that of the first roller surfaces 22a2 and 22b2.

The rotating shafts 22a1 and 22b1 of the folding rollers 22a and 22b are rotationally driven by a common driving means such as a driving motor. As a result, the rotational positions can always be synchronized so that the first roller surfaces 22a2 and 22b2 and the second roller surfaces 22a3 and 22b3 face each other.

When the first roller surfaces 22a2 and 22b2 are opposed to each other, the nip portion 22c is in pressure contact with a predetermined pressing force, and the folded sheet S passes through the nip portion 22c, thereby forming a crease on the sheet. . On the other hand, when the second roller surfaces 22a3 and 22b3 face each other, the nip portion 22c is configured to have a slight gap without contact. Therefore, when the second roller surfaces 22a3 and 22b3 face each other, neither pressing force nor conveying force is applied to the sheet.

When the sheet is folded, the sheet is passed through the nip portion 22c when the first roller surfaces 22a2 and 22b2 face each other, and the sheet is creased and sent to the discharge roller pair 17b. After the sheet is nipped by the discharge roller pair 17b, the folding roller pair 22 is stopped with the second roller surfaces 22a3 and 22b3 facing each other, and the sheet is switchback-conveyed by the discharge roller pair 17b.

As described above, in the configuration in which the sheet is switchback-conveyed by the discharge roller pair 17b as the sheet conveying means in the sheet folding process, the driving speed and the driving timing of the discharge roller pair 17b are controlled. By bending the sheet nipped in the nip portion and having the end portion in contact with the contact portion 26b of the regulating stopper 26 and pressing the sheet against the guide surface of the pressing guide member 30, the folding end portion can be prevented from buckling.

A: Image forming apparatus B: Sheet processing apparatus S: Sheet E1: Leading edge of sheet E2: Folding end portion 17b: Discharge roller pair 20: Sheet conveying path 21: Intermediate tray 21a: Guide surface 22: Folding roller pair 22a, 22b: Folding Roller 22c Nip portion 23 Folding blade 26 Regulation stopper 30 Pressing guide member 50 Grip means 60 Control unit

Claims (21)

The sheet is subjected to a first folding process, and then a second folding process is performed at a position different from the crease formed by the first folding process, and the sheet is folded by the first folding process. In a sheet processing device that performs folding processing so that one end of the is on the inside of the folded sheet,
a conveying path having a guide surface for guiding a sheet conveyed in a predetermined conveying direction;
A first direction in which the sheet conveyed to the conveying path is nipped by the nip portion and rotated to pull in the sheet and perform the folding process, and a direction opposite to the direction in which the folded sheet is pulled in. a pair of rotating bodies capable of switching back and conveying the sheet in the second direction;
a position adjusting means having a contact portion with which an end portion of the sheet conveyed on the conveying path abuts, and capable of moving in the conveying direction and a direction opposite to the conveying direction to adjust the position of the sheet;
a projecting member for projecting the sheet conveyed to the conveying path toward the nip portion of the pair of rotating bodies;
A standby position that does not act on the sheet conveyed on the conveying path, and guides the sheet folded by the pair of rotating bodies and conveyed in the second direction so as to change its orientation in the conveying direction. a redirecting member movable to a guide position;
a control unit that drives and controls the pair of rotating bodies, the position adjusting means, and the direction changing member;
with
When the sheet that has been folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then moves the direction changing member to the guide position. drives and controls the rotating body pair, the position adjusting means, and the direction changing member so that the sheet in contact with the contact portion is pressed against the direction changing member. The sheet is subjected to a first folding process, and then a second folding process is performed at a position different from the crease formed by the first folding process, and the sheet is folded by the first folding process. In a sheet processing device that performs folding processing so that one end of the is on the inside of the folded sheet,
a conveying path having a guide surface for guiding a sheet conveyed in a predetermined conveying direction;
A first direction in which the sheet conveyed to the conveying path is nipped and rotated by the nip portion to be pulled in, and a switchback in a direction opposite to the drawn-in direction to convey the sheet in a second direction. a possible means of transport;
a pair of rotating bodies for folding the sheet conveyed to the conveying path by nipping the sheet at the nip portion and rotating the sheet;
a position adjusting means having a contact portion with which an end portion of the sheet conveyed on the conveying path abuts, and capable of moving in the conveying direction and a direction opposite to the conveying direction to adjust the position of the sheet;
a projecting member for projecting the sheet conveyed to the conveying path toward the nip portion of the pair of rotating bodies;
A standby position that does not act on the sheet conveyed on the conveying path, and guides the sheet folded by the pair of rotating bodies and conveyed in the second direction so as to change its orientation in the conveying direction. a redirecting member movable to a guide position;
a control unit that drives and controls the conveying means, the position adjusting means, and the direction changing member;
with
When the sheet that has been folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position and then nips the sheet by the conveying means. A sheet processing apparatus according to claim 1, wherein the conveying means and the position adjusting means are driven and controlled so that the sheet in contact with the contact portion is pressed against the direction changing member. The control unit moves the direction changing member to the guide position and then moves the position adjusting means closer to the direction changing member when the sheet folded by the pair of rotating bodies is switched back. 3. The sheet processing apparatus according to claim 1, wherein the sheet is pressed against the direction changing member. The control unit moves the direction changing member to the guide position and then moves the position adjusting means in the conveying direction when the sheet folded by the pair of rotating bodies is switched back. 2. The sheet is pressed against the direction changing member by making the conveying speed of the sheet conveyed in the second direction by the pair of rotating bodies higher than the speed to provide a moving speed difference. A sheet processing apparatus as described. The control unit moves the direction changing member to the guide position and then moves the position adjusting means in the conveying direction when the sheet folded by the pair of rotating bodies is switched back. 3. The sheet according to claim 2, wherein the conveying speed of the sheet conveyed in the second direction by the conveying means is made higher than the speed to provide a moving speed difference so that the sheet is pressed against the direction changing member. sheet processing equipment. The movement speed difference is larger when the number of sheets is equal to or greater than a predetermined number than when the number is less than the predetermined number, or is greater when the basis weight of the sheets is equal to or greater than a predetermined value than when the basis weight is less than the predetermined value. The sheet processing apparatus according to claim 4 or 5. When the sheet folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then the end portion of the sheet in the conveying path The rotating member pair starts conveying the sheet in the second direction while being in contact with the contact portion, and after a predetermined time has passed, the position adjusting means starts moving in the conveying direction. 2. The sheet processing apparatus according to claim 1, wherein the sheet is pressed against the direction changing member. When the sheet folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then the end portion of the sheet in the conveying path The conveying means starts conveying the sheet in the second direction while it is in contact with the contact portion, and after a predetermined time has passed, the position adjusting means starts moving in the conveying direction. 3. The sheet processing apparatus according to claim 2, wherein the sheet is pressed against the changing member. The predetermined time is longer when the number of sheets is equal to or greater than the predetermined number than when the number of sheets is less than the predetermined number, or is longer when the basis weight of the sheet is equal to or greater than a predetermined value than when the basis weight is less than the predetermined value. Item 9. The sheet processing apparatus according to item 7 or 8. a sheet gripping means for holding an edge of the sheet in contact with the contact portion of the position adjusting means;
10. The sheet processing apparatus according to any one of claims 1 to 9, wherein the sheet grip means grips an end portion of the sheet when the sheet that has been folded by the pair of rotating bodies is switched back. an image forming apparatus for forming an image on a sheet; and a first folding process for the sheet on which the image is formed by the image forming apparatus, and then at a position different from the fold formed by the first folding process. a sheet processing device that performs a second folding process so that one end of the sheet folded by the first folding process is inside the sheet that is folded the second time; and the image forming apparatus. In an image forming system comprising an apparatus and a control section for controlling driving of the sheet processing apparatus,
The sheet processing device includes:
a conveying path having a guide surface for guiding a sheet conveyed in a predetermined conveying direction;
A first direction in which the sheet conveyed to the conveying path is nipped by the nip portion and rotated to pull in the sheet and perform the folding process, and a direction opposite to the direction in which the folded sheet is pulled in. a pair of rotating bodies capable of switching back and conveying the sheet in the second direction;
a position adjusting means having a contact portion with which an end portion of the sheet conveyed on the conveying path abuts, and capable of moving in the conveying direction and a direction opposite to the conveying direction to adjust the position of the sheet;
a projecting member for projecting the sheet conveyed to the conveying path toward the nip portion of the pair of rotating bodies;
A standby position that does not act on the sheet conveyed on the conveying path, and guides the sheet folded by the pair of rotating bodies and conveyed in the second direction so as to change its orientation in the conveying direction. a redirecting member movable to a guide position;
with
When the sheet that has been folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then moves the direction changing member to the guide position. drives and controls the rotating body pair, the position adjusting means, and the direction changing member so that the sheet in contact with the contact portion is pressed against the direction changing member. an image forming apparatus for forming an image on a sheet; and a first folding process for the sheet on which the image is formed by the image forming apparatus, and then at a position different from the fold formed by the first folding process. a sheet processing device that performs a second folding process so that one end of the sheet folded by the first folding process is inside the sheet that is folded the second time; and the image forming apparatus. In an image forming system comprising an apparatus and a control section for controlling driving of the sheet processing apparatus,
The sheet processing device includes:
a conveying path having a guide surface for guiding a sheet conveyed in a predetermined conveying direction;
A first direction in which the sheet conveyed to the conveying path is nipped and rotated by the nip portion to be pulled in, and a switchback in a direction opposite to the drawn-in direction to convey the sheet in a second direction. a possible means of transport;
a pair of rotating bodies for folding the sheet conveyed to the conveying path by nipping the sheet at the nip portion and rotating the sheet;
a position adjusting means having a contact portion with which an end portion of the sheet conveyed on the conveying path abuts, and capable of moving in the conveying direction and a direction opposite to the conveying direction to adjust the position of the sheet;
a projecting member for projecting the sheet conveyed to the conveying path toward the nip portion of the pair of rotating bodies;
A standby position that does not act on the sheet conveyed on the conveying path, and guides the sheet folded by the pair of rotating bodies and conveyed in the second direction so as to change its orientation in the conveying direction. a redirecting member movable to a guide position;
with
When the sheet that has been folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position and then nips the sheet by the conveying means. An image forming system, wherein the conveying means and the position adjusting means are driven and controlled so that the sheet in contact with the contact portion is pressed against the direction changing member. The control unit moves the direction changing member to the guide position and then moves the position adjusting means closer to the direction changing member when the sheet folded by the pair of rotating bodies is switched back. 13. The image forming system according to claim 11, wherein the sheet is pressed against the direction changing member. The control unit moves the direction changing member to the guide position and then moves the position adjusting means in the conveying direction when the sheet folded by the pair of rotating bodies is switched back. 12. The sheet is pressed against the direction changing member by making the conveying speed of the sheet conveyed in the second direction by the pair of rotating bodies higher than the conveying speed so as to provide a moving speed difference. The described imaging system. The control unit moves the direction changing member to the guide position and then moves the position adjusting means in the conveying direction when the sheet folded by the pair of rotating bodies is switched back. 13. The sheet according to claim 12, wherein the conveying speed of the sheet conveyed in the second direction by the conveying means is made higher than the speed to provide a moving speed difference, thereby pressing the sheet against the direction changing member. image forming system. The movement speed difference is larger when the number of sheets is equal to or greater than a predetermined number than when the number is less than the predetermined number, or is greater when the basis weight of the sheets is equal to or greater than a predetermined value than when the basis weight is less than the predetermined value. 16. The image forming system according to claim 14 or 15. When the sheet folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then the end portion of the sheet in the conveying path The rotating member pair starts conveying the sheet in the second direction while being in contact with the contact portion, and after a predetermined time has passed, the position adjusting means starts moving in the conveying direction. 12. The image forming system of claim 11, wherein the sheet is pressed against the direction changing member. When the sheet folded by the pair of rotating bodies is switched back, the control section moves the direction changing member to the guide position, and then the end portion of the sheet in the conveying path The conveying means starts conveying the sheet in the second direction while it is in contact with the contact portion, and after a predetermined time has passed, the position adjusting means starts moving in the conveying direction. 13. The image forming system according to claim 12, wherein the sheet is pressed against the changing member. The predetermined time is longer when the number of sheets is equal to or greater than the predetermined number than when the number of sheets is less than the predetermined number, or is longer when the basis weight of the sheet is equal to or greater than a predetermined value than when the basis weight is less than the predetermined value. 19. The image forming system according to item 17 or 18. a sheet gripping means for holding an edge of the sheet in contact with the contact portion of the position adjusting means;
20. The image forming system according to any one of claims 11 to 19, wherein when the sheet that has been folded by the pair of rotating bodies is switched back, the sheet grip means grips an edge of the sheet. 21. The image forming system according to claim 11, wherein the controller is provided in the image forming apparatus or the sheet processing apparatus.

Images