EP4789996A1

EP4789996A1 - Sheet post-processing apparatus and image forming system

Info

Publication number: EP4789996A1
Application number: EP26155768.0A
Authority: EP
Inventors: Tadahisa Kishimoto
Original assignee: Kyocera Document Solutions Inc
Current assignee: Kyocera Document Solutions Inc
Priority date: 2025-02-06
Filing date: 2026-02-02
Publication date: 2026-08-12

Abstract

A sheet post-processing apparatus (100) includes a discharge port (101), a discharge section (2), a discharge tray (T1), a processing tray (3), a folding section (1), a support member (5) that includes a support portion (50) supporting a part of a sheet (S) placed on the processing tray (3) from below, the part protruding via the discharge port (101) so as to be positioned above a discharge tray (T1), and that is movable between a protrusion position, at which the support portion (50) protrudes so as to be positioned above the discharge tray (T1), and a retraction position, at which the support portion (50) is retracted, and a control section (7). When newly loading a Z-folded sheet (Sz) onto the processing tray (3) in a state in which a sheet (S) is placed thereon, the control section (7) moves the support member (5) from the protrusion position to the retraction position.

Description

BACKGROUND

The present disclosure relates to a sheet post-processing apparatus and an image forming system.
A conventional sheet post-processing device is coupled to an image forming apparatus. The image forming apparatus prints an image on a sheet, and feeds the printed sheet to the sheet post-processing apparatus. The sheet post-processing apparatus is capable of executing, as one step of post-processing, folding processing to fold the printed sheet.

SUMMARY

According to one aspect of the present disclosure, a sheet post-processing apparatus includes a discharge port, a discharge section, a discharge tray, a processing tray, a folding section, a support member, and a control section. Through the discharge port, a sheet is discharged. The discharge section conveys a sheet to discharge the sheet through the discharge port. Onto the discharge tray, the sheet discharged through the discharge port is loaded. The processing tray is disposed upstream of the discharge port in a sheet conveyance direction, and a sheet is loaded onto the processing tray to be subjected to a predetermined post-processing. The folding section performs, as post-processing, folding processing to Z-fold a sheet, and conveys a Z-folded sheet, which is obtained by subjecting the sheet to the folding processing, toward the processing tray. The support member includes a support portion supporting, from below, a part of the sheet placed on the processing tray, the part protruding via the discharge port so as to be positioned above the discharge tray, and that is movable between a protrusion position at which the support portion protrudes from upstream of the discharge port in the sheet conveyance direction so as to be positioned above the discharge tray and a retraction position at which the support portion is retracted to a position upstream of the discharge port in the sheet conveyance direction. The control section controls a position of the support member. When newly loading the Z-folded sheet onto the processing tray in a state in which a sheet is placed on the processing tray, the control section moves the support member from the protrusion position to the retraction position.
According to a second aspect of the present disclosure, an image forming system includes the sheet post-processing apparatus and an image forming apparatus. The image forming apparatus prints an image on a sheet and feeds the sheet printed to the sheet post-processing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exterior view of an image forming system according to an embodiment.
FIG. 2 is a schematic view showing an inner configuration of a sheet post-processing apparatus according to an embodiment.
FIG. 3 is a side view of a processing tray and its surroundings of the sheet post-processing apparatus according to the embodiment as seen from a width direction.
FIG. 4 is a perspective view of the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 5 is a schematic diagram for illustrating a process of loading a sheet onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 6 is a schematic diagram for illustrating the process of loading a sheet onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 7 is a schematic diagram for illustrating the process of loading a sheet onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 8 is a schematic diagram showing a support member and its surroundings of the sheet post-processing apparatus according to the embodiment.
FIG. 9 is a schematic diagram showing a sheet having been Z-folded by the sheet post-processing apparatus according to the embodiment.
FIG. 10 is a schematic diagram showing a folding section and its surroundings of the sheet post-processing apparatus according to the embodiment.
FIG. 11 is a schematic diagram for illustrating folding processing performed in the sheet post-processing apparatus according to the embodiment.
FIG. 12 is a schematic diagram for illustrating the folding processing performed in the sheet post-processing apparatus according to the embodiment.
FIG. 13 is a schematic diagram for illustrating how the support member operates when loading a sheet onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 14 is a schematic diagram for illustrating how the support member operates when a sheet is loaded onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 15 is a schematic diagram for illustrating how the support member operates when a sheet is loaded onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 16 is a schematic diagram for illustrating how the support member operates when a sheet is loaded onto the processing tray of the sheet post-processing apparatus according to the embodiment.
FIG. 17 is a schematic diagram for illustrating how the support member operates when a sheet is loaded onto the processing tray of the sheet post-processing apparatus according to the embodiment.

DETAILED DESCRIPTION

As shown in FIG. 1, an image forming system 100S of the present embodiment includes a sheet post-processing apparatus 100 and an image forming apparatus 200. The sheet post-processing apparatus 100 is coupled to the image forming apparatus 200. The sheet post-processing apparatus 100 is coupled to the image forming apparatus 200, thereby constituting the image forming system 100S together with the image forming apparatus 200.
For example, the sheet post-processing apparatus 100 is an optional apparatus, and is attachable and detachable to and from the image forming apparatus 200. The sheet post-processing device 100 is disposed outside the image forming apparatus 200. Note that this arrangement is not meant as a limitation. The sheet post-processing device 100 may be installed within the image forming apparatus 200.
The image forming apparatus 200 is a multifunction peripheral having a plurality of functions including a copying function. Note that the image forming apparatus 200 may be a printer. The image forming apparatus 200 conveys a sheet S (not shown in FIG. 1), and prints an image on the sheet S while it is being conveyed. Then, the image forming apparatus 200 feeds the printed sheet S to the sheet post-processing apparatus 100. There is no particular limitation on the type of the sheet S, and a sheet of paper may be used as the sheet S.
The image forming apparatus 200 includes a printing section (not shown). The printing section prints an image on a sheet S. The printing section may employ an inkjet printing method, or may employ an electrophotographic printing method.
In a case where the printing section employs the inkjet printing method, the printing section at least includes an ink head. The printing section uses ink to print an image on a sheet S. Specifically, the printing section ejects ink onto the sheet S such that the ink adhere to the sheet S.
In a case where the printing section employs the electrophotographic printing method, the printing section includes components such as a photosensitive drum, a charging device, a developing device, an exposure device, a transfer roller, and the like. The printing section uses toner to print an image on a sheet S. Specifically, the printing section forms an electrostatic latent image and transfer a toner image, obtained by developing the electrostatic latent image, onto the sheet S.
The sheet post-processing apparatus 100 receives a sheet S from the image forming apparatus 200. The sheet post-processing apparatus 100 conveys the sheet S and performs on it, as post-processing, punching processing, folding processing, stapling processing, booklet processing, etc. These types of post-processing mentioned just above are merely examples and do not all need to be implemented. Further, other types of post-processing may also be implemented.
Note that the sheet post-processing device 100 may be usable independently. In that case, the sheet post-processing apparatus 100 is provided with a set tray for setting a sheet S thereon. The sheet post-processing apparatus 100 conveys into itself the sheet S set on the set tray, and performs post-processing with respect to the set sheet S.

As shown in FIG. 2, the sheet post-processing apparatus 100 is installed on a floor surface FL that is substantially flat. A direction perpendicular to the floor surface FL (i.e., a vertical direction) is an up-down direction of the sheet post-processing apparatus 100. Among directions parallel to the floor surface FL (i.e., horizontal directions), a direction perpendicular to the sheet plane of FIG. 2 is a front-rear direction of the sheet post-processing apparatus 100, and a left-right direction in FIG. 2 is a left-right direction of the sheet post-processing apparatus 100.
The sheet post-processing apparatus 100 includes a feed port 1000, a main discharge port 101, and a sub discharge port 102. The sheet post-processing apparatus 100 further includes a main tray T1 and a sub tray T2. The main discharge port 101 corresponds to an "discharge port". The main tray T1 corresponds to a "discharge tray".
The feed port 1000 is located on a side of the sheet post-processing apparatus 100 where the sheet post-processing apparatus 100 is coupled to the image forming apparatus 200. Via the feed port 1000, a sheet S is fed from the image forming apparatus 200 into the sheet post-processing apparatus 100. The main discharge port 101 and the sub discharge port 102 are located on a side of the sheet post-processing apparatus 100 that is opposite to the side where the sheet post-processing apparatus 100 is coupled to the image forming apparatus 200. Via either the main discharge port 101 or the sub discharge port 102, the sheet S is discharged from the sheet post-processing apparatus 100.
The main tray T1 and the sub tray T2 are located on the side of the sheet post-processing apparatus 100 that is opposite to the side where the sheet post-processing apparatus 100 is coupled to the image forming apparatus 200. Above the main tray T1, the sub tray T2 is disposed. The sheet post-processing apparatus 100 discharges and loads the sheet S onto the main tray T1 or the sub tray T2. Onto the main tray T1, a sheet S discharged through the main discharge port 101 is loaded, and onto the sub tray T2, a sheet S discharged through the sub discharge port 102 is loaded.
The sheet post-processing apparatus 100 includes a first conveyance path P1 and a second conveyance path P2. The first conveyance path P1 and the second conveyance path P2 are each a conveyance path for a sheet S. The first conveyance path P1 extends substantially horizontally from the feed port 1000 and leads to the main discharge port 101. The second conveyance path P2 branches diagonally upward to the left from the first conveyance path P1 and leads to the sub discharge port 102.
The sheet post-processing apparatus 100 conveys a sheet S from the feed port 1000 toward the main tray T1 or the sub tray T2. That is, a direction from right toward left within the sheet post-processing apparatus 100 is a sheet conveyance direction. A direction in which a sheet S is conveyed within the sheet post-processing apparatus 100 is the sheet conveyance direction.
The sheet post-processing apparatus 100 includes a punch unit PU, a stapler unit SU, and a booklet unit BU. The punch unit PU, the stapler unit SU, and the booklet unit BU each perform a corresponding step of post-processing on the sheet S.
The punch unit PU is disposed along the first conveyance path P1 so as to be positioned on an upstream side in the sheet conveyance direction. The punch unit PU performs, as post-processing, the punching processing to punch a hole in the sheet S. Through the punching processing, a punch hole is formed in the sheet S.
The stapler unit SU performs, as post-processing, the stapling processing to bind a bundle of sheets S with a staple needle. In the stapling processing, a plurality of sheets S are loaded onto a processing tray 3, which will be described later. The stapler unit SU performs the stapling processing with respect to the plurality of sheets S stacked on the processing tray 3.
The booklet unit BU performs, as post-processing, the booklet processing to fold a center-bound bundle of sheets S in the center. The booklet unit BU includes a stapling portion for center-stapling, and uses the stapling portion to bind the bundle of sheets S in the center with a staple needle.
Note that the sheet post-processing apparatus 100 includes a third conveyance path P3 that branches off from the first conveyance path P1 to extend downward. The third conveyance path P3 leads to the booklet unit BU. In a case where the booklet processing is performed, a sheet S is conveyed via the third conveyance path P3 to the booklet unit BU.
The sheet post-processing apparatus 100 further includes a booklet tray T3. The booklet tray T3 is provided on the side of the sheet post-processing apparatus 100 that is opposite to the side where the sheet post-processing apparatus 100 is coupled to the image forming apparatus 200.
The booklet tray T3 is disposed below the main tray T1. Onto the booklet tray T3, a booklet obtained through the booklet processing is discharged.
Here, the sheet post-processing apparatus 100 includes a folding section 1. The folding section 1 performs, as post-processing, the folding processing to fold a sheet S. The folding section 1 conveys the sheet S folded through the folding processing toward the main discharge port 101.
Details of the folding section 1 will be described later.

As shown in FIG. 2, the sheet post-processing apparatus 100 includes a plurality of conveyance roller pairs. The plurality of conveyance roller pairs each include a pair of rollers that are pressed against each other. Each of the plurality of conveyance roller pairs nips the sheet S between the pair of rollers and rotates, thereby conveying the sheet S.
The sheet post-processing apparatus 100 includes a discharge roller pair 2 as one of the conveyance roller pairs. The discharge roller pair 2 corresponds to a "discharge section". The discharge roller pair 2 is disposed at the main discharge port 101. That is, the discharge roller pair 2 is disposed along the first conveyance path P1. The discharge roller pair 2 nips a sheet S (including a bundle of sheets S on the processing tray 3) at the main discharge port 101, and conveys the sheet S to discharge it through the main discharge port 101. The sheet S discharged through the main discharge port 101 is loaded onto the main tray T1.
The discharge roller pair 2 includes an upper roller 21 and a lower roller 22. The upper roller 21 is disposed on an upper side of the first conveyance path P1, and the lower roller 22 is disposed on a lower side of the first conveyance path P1. The upper roller 21 and the lower roller 22 face each other with the first conveyance path P1 therebetween and are pressed against each other. For example, a discharge motor (not shown) is coupled to the lower roller 22, and when the discharge motor is driven, the lower roller 22 rotates and the upper roller 21 rotates following the lower roller 22. The discharge roller pair 2 nips the sheet S between the upper roller 21 and the lower roller 22. In this state, when the discharge roller pair 2 rotates, the sheet S is discharged through the main discharge port 101.
The upper roller 21 is rotatably supported on one end part of a roller arm (not shown). The roller arm is pivotable about a rotation shaft, which is provided at the other end part of the roller arm, so as to swing the one end part thereof in the up-down direction. In this manner, it is possible to separate the upper roller 21 from the lower roller 22. It is also possible to press the upper roller 21 against the lower roller 22. When discharging a sheet S onto the main tray T1, a state is achieved in which the upper roller 21 and the lower roller 22 are pressed against each other with the sheet S therebetween.
The sheet post-processing apparatus 100 further includes an intermediate roller pair 20 as one of the conveyance roller pairs. The intermediate roller pair 20 is disposed along the first conveyance path P1 so as to be positioned upstream of the discharge roller pair 2 but downstream of the punch unit PU in the sheet conveyance direction. The intermediate roller pair 20 conveys a sheet S toward the main discharge port 101.
Note that the intermediate roller pair 20 is disposed downstream of the folding section 1 in the sheet conveyance direction. With this arrangement, in a case where a sheet S has been subjected to the folding processing, the sheet S is conveyed by the intermediate roller pair 20 toward the main discharge port 101.

The sheet post-processing apparatus 100 includes the processing tray 3. The processing tray 3 is positioned below the lower side of a sheet S conveyed along the first conveyance path P1. The processing tray 3 is inclined diagonally downward from a downstream side toward an upstream side in the sheet conveyance direction. That is, the processing tray 3 is inclined diagonally downward from one end toward the other end thereof. As seen from a front side of the sheet post-processing apparatus 100 (see FIG. 2), the left end of the processing tray 3 is the one end, and the right end is the other end of the processing tray 3.
The one end of the processing tray 3 is located at the main discharge port 101. That is, the processing tray 3 is inclined diagonally downward from the main discharge port 101 toward the upstream side in the sheet conveyance direction. At the one end of the processing tray 3, the lower roller 22 is disposed.
The stapler unit SU is disposed at the other end of the processing tray 3. When stapling processing is performed, a plurality of sheets S are loaded on the processing tray 3. The stapler unit SU performs the stapling processing with respect to a bundle of sheets S stacked on the processing tray 3. That is, the stapling processing corresponds to "predetermined post-processing".
At the other end of the processing tray 3, a reference plate 30 (see FIG. 3) is disposed. In FIG. 3, the sheet conveyance direction in which a sheet S is conveyed along the first conveyance path P1 is indicated by an arrow Ds. Rear ends of sheets S on the processing tray 3 each come into contact with the reference plate 30, as a result of which the rear-end positions of the sheets S are aligned. That is, it is possible to suppress occurrence of misalignment where the rear-end positions of the sheets S on the processing tray 3 are misaligned. By performing the stapling processing, with the rear-end positions of the sheets S on the processing tray 3 in alignment, it is possible to suppress misalignment of stapling positions between the each sheet S.
As shown in FIG. 4, the processing tray 3 has a pair of processing-tray cursors 31. The pair of processing-tray cursors 31 includes one cursor and the other cursor that are respectively disposed on one side and the other side of a center of the processing tray 3 in a width direction Dw thereof (a direction orthogonal to the sheet conveyance direction). The pair of processing-tray cursors 31 are independently movable on the processing tray 3 along the width direction Dw.
The sheets S on the processing tray 3 are sandwiched between the pair of processing-tray cursors 31 in the width direction Dw. In this manner, the sheets S are aligned in the width direction Dw on the processing tray 3. Performing the stapling processing in this state helps prevent misalignment of the staple positions between the each sheet S.
Furthermore, the pair of processing-tray cursors 31 are movable in the same direction along the width direction Dw while sandwiching each sheet S on the processing tray 3 therebetween in the width direction Dw. This makes it possible to perform, as post-processing, shift processing to shift a bundle of sheets S on the processing tray 3 in the width direction Dw. Performing the shift processing on the processing tray 3 makes it possible to shift stacking positions of bundles of sheets S from each bundle of sheets S on the main tray T1, the bundles of sheets S each being discharged from the processing tray 3 through the main discharge port 101. The shift processing is performed with respect to a sheet S placed on the processing tray 3. That is, the shift processing corresponds to "predetermined post-processing".

The sheet post-processing apparatus 100 includes a pull-in member 4 as shown in FIGS. 5 to 7. In a case of loading a sheet S onto the processing tray 3, the pull-in member 4 pulls in the sheet S to the processing tray 3. In a case of not loading a sheet S onto the processing tray 3, the pull-in member 4 does not pull in the sheet S to the processing tray 3.
The pull-in member 4 is not particularly limited in configuration. For example, the pull-in member 4 includes a paddle 41 and a paddle holder 42.
The paddle 41 is disposed above the processing tray 3. The paddle 41 includes a pair of rubber sheets. The pair of rubber sheets protrude in tangential directions from point-symmetric positions on an outer circumferential surface of a rotation shaft that is orthogonal to the sheet conveyance direction.
The paddle holder 42 supports the paddle 41 in a rotatable manner at one end thereof. In FIGS. 5 to 7, the paddle 41 rotates in a counterclockwise direction. Further, the paddle holder 42 includes a swing shaft 42a disposed at the other end thereof. The paddle holder 42 is swingable about the swing shaft 42a functioning as a fulcrum so as to swing the one end thereof supporting the paddle 41 in the up-down direction.
Hereinafter, a description will be given of a process in which a sheet S is loaded onto the processing tray 3 by the pull-in member 4. In the following description, a front end part (a downstream-side part in the sheet conveyance direction) of the sheet S is denoted by a symbol Sf and a rear end part (an upstream-side part in the sheet conveyance direction) of the sheet S is denoted by a symbol Sr.
After the rear end part Sr of the sheet S conveyed by the intermediate roller pair 20 has passed through the intermediate roller pair 20, the front end part Sf of the sheet S protrudes from the main discharge port 101 to be positioned above the main tray T1, and in this state, the pull-in member 4 switches back the sheet S to pull in the sheet S to the processing tray 3. As a result of the sheet S being pulled in by the pull-in member 4, the rear end part Sr of the sheet S is brought into contact with the reference plate 30.
Specifically, when loading the sheet S onto the processing tray 3, as shown in FIG. 5, the paddle 41 is held at a position out of contact with the sheet S. Further, the nip of the discharge roller pair 2 (the state of the upper roller 21 being pressed against the lower roller 22) is released, as a result of which the main discharge port 101 is opened. In this state, the sheet S is conveyed by the intermediate roller pair 20. In this manner, the front end part Sf of the sheet S that is being conveyed by the intermediate roller pair 20 protrudes from the main discharge port 101 so as to be positioned above the main tray T1. In FIG. 5, the sheet conveyance direction in which the sheet S is conveyed by the intermediate roller pair 20 is indicated by an arrow D1.
After the conveyance of the sheet S by the intermediate roller pair 20 is started, when the rear end part Sr of the sheet S that is being conveyed has passed through the intermediate roller pair 20, the paddle 41 moves toward the processing tray 3 as shown in FIG. 6, and as a result, the paddle 41 contacts the sheet S to lay the sheet S along an upper surface of the processing tray 3. Further, in this state, the paddle 41 rotates. Note that the sheet S may be tapped toward the processing tray 3 using an unillustrated tapping member when the rear end part Sr of the sheet S that is being conveyed by the intermediate roller pair 20 has passed through the intermediate roller pair 20.
When the paddle 41 rotates in contact with the sheet S, the sheet S is caused to move along the upper surface of the processing tray 3 toward the reference plate 30 as illustrated in FIG. 7. In other words, the sheet S slides down along the upper surface of the processing tray 3. In still other words, the sheet S is switched back. As a result, the rear end part Sr of the sheet S (the rear end thereof) comes into contact with the reference plate 30. In FIG. 7, a direction in which the sheet S moves at this time is indicated by an arrow D2.
Subsequently, the paddle 41 moves upward. Thereafter, the same operation is repeated until the number of sheets S stacked on the processing tray 3 reaches a set number.
When the number of sheets S stacked on the processing tray 3 reaches the set number, the bundle of the sheets S on the processing tray 1 is sandwiched by the pair of processing-tray cursors 31 in the width direction Dw, and in that state, at least one of the stapling processing and the shift processing is performed. That is, the predetermined post-processing is performed.
Then, the bundle of sheets S on the processing tray 3 is nipped by the discharge roller pair 2, and in that state, the discharge roller pair 2 rotates. In this manner, the bundle of sheets S on the processing tray 3 is discharged through the main discharge port 101 to be loaded onto the main tray T1.
Here, as shown in FIG. 8, the sheet post-processing apparatus 100 includes a support member 5. The support member 5 includes a support portion 50. The support member 5 is movable between a protrusion position and a retraction position. The protrusion position is a position at which the support portion 50 protrudes from an upstream side of the main discharge port 101 in the sheet conveyance direction so as to be positioned above the main tray T1. The retraction position is a position at which the support portion 50 is retracted to a position upstream of the main discharge port 101 in the sheet conveyance direction. In FIG. 8, the support member 5 located at the retraction position is indicated by a solid line, and the support portion 50 of the support member 5 located at the protruding position is indicated by a broken line.
The support member 5 is a rod-like member and is formed in an arc shape. The support member 5 is movable in an extension direction thereof. As the support member 5, two support members 5 are provided. The two support members 5 are aligned with a space therebetween in a direction orthogonal to the sheet conveyance direction.
The sheet post-processing apparatus 100 includes a support-member moving mechanism 6. The support-member moving mechanism 6 includes a motor 60. The support-member moving mechanism 6 causes the support member 5 to move between the protrusion position and the retraction position. The support-member moving mechanism 6 includes a pinion gear (not shown) coupled to the motor 60. The support member 5 is provided with a rack gear that meshes with the pinion gear. The pinion gear rotates by receiving power from the motor 60. The rack gear includes a plurality of teeth aligned in the extension direction of the support member 5. The support-member moving mechanism 6 drives the motor 60 (that is, causes the pinion gear to rotate) to thereby move the support member 5 in the extension direction of the support member 5.
The sheet post-processing apparatus 100 includes a control section 7 (see FIG. 2).
The control section 7 includes processing circuits such as a CPU, an ASIC, etc. The control section 7 further includes a recording device such as a ROM, a RAM, etc. The control section 7 communicates with a main body control section (not shown) of the image forming apparatus 200.
The control section 7 receives job information from the main body control section. Job information includes pieces of information such as information regarding post-processing to be executed in the sheet post-processing apparatus 100, information regarding the number of copies to be printed, information regarding the number of sheets to be printed, etc. Information regarding the folding processing includes information indicating which sheet number should to be subjected to the folding processing. Based on these pieces of information, the control section 7 controls the sheet post-processing apparatus 100.
The motor 60 is connected to the control section 7. The control section 7 controls the motor 60. In other words, the control section 7 controls the support-member moving mechanism 6. In still other words, the control section 7 controls the position of the support member 5. The control section 7 causes the support member 5 to move to the protrusion position or to move to the retraction position.

As shown in FIG. 2, the folding section 1 is disposed downstream of the punch unit PU in the sheet conveyance direction. The folding section 1 performs the folding processing with respect to a sheet S conveyed from the punch unit PU. Note that the folding processing may be performed with respect to a sheet S in which a punch hole has been formed, or may be performed with respect to a sheet S in which no punch hole has been formed.
The folding processing that can be executed at the folding section 1 includes processing of Z-folding a sheet S. Through this processing performed as the folding processing, a sheet S as shown in FIG. 9 can be obtained. Hereinafter, a Z-folded sheet will be denoted by a symbol Sz, and will be referred to simply as a Z-folded sheet Sz.
In a Z-folded sheet Sz, a part thereof on a front end side (that is, on a downstream side in the sheet conveyance direction) is bent in a Z-shape. Specifically, the Z-folded sheet Sz has a first fold F1 and a second fold F2. The Z-folded sheet Sz has a Z-folded part including a first part S1 and a second part S2. The first part S1 extends from a front end of the Z-folded sheet Sz to the first fold F1, and the second part S2 extends from the first fold F1 to the second fold F2. The first part S1 and the second part S2 face each other.
The folding section 1 performs the folding processing such as Z-folding a sheet S while conveying the sheet S. For this purpose, the folding section 1 includes a conveyance path for a sheet S as a component.
Specifically, as shown in FIG. 10, the folding section 1 includes a first folding conveyance path FP1 and a second folding conveyance path FP2. The first folding conveyance path FP1 constitutes part of the third conveyance path P3. The first folding conveyance path FP1 branches off from the first conveyance path P1 to extend downward. The second folding conveyance path FP2 branches off from the first folding conveyance path FP1. The second folding conveyance path FP2 then joins the first conveyance path P1 at a position downstream, in the sheet conveyance direction, of the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1.
Hereinafter, regarding the first folding conveyance path FP1, a sheet conveyance direction in the first folding conveyance path FP1 is defined as a direction toward the booklet unit BU from the branching position at which the first folding conveyance path FP1 (that is, the third conveyance path P3) branches off from the first conveyance path P1. That is, the sheet conveyance direction in the first folding conveyance path FP1 is the direction along which a sheet S is pulled into the first folding conveyance path FP1 from the first conveyance path P1. Regarding the second folding conveyance path FP2, a sheet conveyance direction in the second folding conveyance path FP2 is defined as a direction toward the joining position at which the first conveyance path P1 joins the second folding conveyance path FP2 from the branching position at which the first folding conveyance path FP1 branches off from the second folding conveyance path FP2.
The folding section 1 includes a folding roller train 10 including a plurality of rollers. The folding roller train 10 includes a first roller R1, a second roller R2, a third roller R3, and a fourth roller R4. To the second roller R2 or the third roller R3 in the folding roller train 10, a folding motor (not shown) is coupled. That is, in the folding roller train 10, the second roller R2 or the third roller R3 is a driving roller, and the other rollers are driven rollers that rotate following the driving roller.
The first roller R1 and the second roller R2 are disposed so as to face each other with the first conveyance path P1 therebetween. The first roller R1 and the second roller R2 are pressed against each other, thereby forming a nip on the first conveyance path P1. Note that the second roller R2 is pressed against the first roller R1 from below the first conveyance path P1. In the following description, the nip formed between the first roller R1 and the second roller R2 is denoted by a symbol N0 and referred to as a conveyance nip N0.
The third roller R3 is disposed downstream of the second roller R2 in the sheet conveyance direction so as to be below the first conveyance path P1. The third roller R3 faces the second roller R2 with the first folding conveyance path FP1 therebetween. The third roller R3 and the second roller R2 are pressed against each other, thereby forming a nip on first folding conveyance path FP1. In the following description, the nip formed between the third roller R3 and the second roller R2 is denoted by a symbol FN1 and referred to as a first folding nip FN1.
The fourth roller R4 is disposed below the third roller R3. The fourth roller R4 faces the third roller R3 with the second folding conveyance path FP2 therebetween. The fourth roller R4 and the third roller R3 are pressed against each other, thereby forming a nip on the second folding conveyance path FP2. In the following description, the nip formed between the fourth roller R4 and the third roller R3 is denoted by a symbol FN2 and referred to as a second folding nip FN2.
The first roller R1 and the second roller R2 respectively rotate in directions for conveying a sheet S toward the main discharge port 101 (that is, the intermediate roller pair 20). Specifically, the first roller R1 rotates clockwise in FIG. 8 and the second roller R2 rotates counterclockwise in FIG. 8. As a result, the third roller R3 rotates clockwise in FIG. 8. The fourth roller R4 rotates counterclockwise in FIG. 8.
The folding section 1 includes a first switchback roller pair 11. The first switchback roller pair 11 include a pair of rollers disposed so as to face each other in the up-down direction with the first conveyance path P1 therebetween. The pair of rollers constituting the first switchback roller pair 11 are pressed against each other, thereby forming a nip on the first conveyance path P1. The nip is positioned on the first conveyance path P1 so as to be downstream of the conveyance nip N0 in the sheet conveyance direction. In the following description, the nip formed by the first switchback roller pair 11 is denoted by a symbol SN1 and referred to as a first switchback nip SN1.
The first switchback roller pair 11 is driven by a motor that is separate from the motor that drives the folding roller train 10. One roller of the first switchback roller pair 11 is a driving roller, and the other roller of the first switchback roller pair 11 is a driven roller that rotates following the one roller.
The first switchback roller pair 11 is rotatable forward and backward. That is, the motor that drives the first switchback roller pair 11 is rotatable forward and backward. By rotating forward, the first switchback roller pair 11 conveys a sheet S toward the main discharge port 101.
By rotating backward, the first switchback roller pair 11 switches back a sheet S that is being conveyed.
The folding section 1 includes a second switchback roller pair 12. The second switchback roller pair 12 includes a pair of rollers disposed so as to face each other in the up-down direction with the first folding conveyance path FP1 therebetween. The pair of rollers constituting the second switchback roller pair 12 are pressed against each other, thereby forming a nip on the first folding conveyance path FP1. The nip is positioned on the first folding conveyance path FP1 so as to be downstream of the first folding nip FN1 in the sheet conveyance direction. In the following description, the nip formed by the second switchback roller pair 12 is denoted by a symbol SN2 and referred to as a second switchback nip SN2.
The second switchback roller pair 12 is driven by a motor separate from the motors that respectively drive the folding roller train 10 and the first switchback roller pair 11. One roller of the second switchback roller pair 12 is a driving roller, and the other roller of the second switchback roller pair 12 is a driven roller that rotates following the one roller.
The second switchback roller pair 12 is rotatable forward and backward. That is, the motor that drives the second switchback roller pair 12 is rotatable forward and backward. The second switchback roller pair 12 rotates forward, thereby conveying a sheet S toward the booklet unit BU. In other words, the second switchback roller pair 12 rotates forward, thereby rotating in the direction in which a sheet S is pulled from the first conveyance path P1 into the first folding conveyance path FP1. The second switchback roller pair 12 rotates backward, thereby switching back a sheet S that is being conveyed.
The folding section 1 further includes a first guide G1 and a second guide G2. The first guide G1 is disposed at the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1. The second guide G2 is disposed at the branching position at which the second folding conveyance path FP2 branches off from the first folding conveyance path FP1.
The first guide G1 is coupled to a first-guide driving mechanism, which is not illustrated. The first-guide driving mechanism includes a drive source composed of a motor and a solenoid, for example, and drives the first guide G1. The first guide G1 is movable in a direction approaching the first folding nip FN1 and in an opposite direction separating from the first folding nip FN1 by receiving a driving force from the first-guide driving mechanism.
The second guide G2 is coupled to a second-guide driving mechanism, which is not illustrated. The second-guide driving mechanism includes a drive source composed of a motor and a solenoid, for example, and drives the second guide G2. The second guide G2 is movable in a direction approaching the second folding nip FN2 and in an opposite direction separating from the second folding nip FN2 by receiving a driving force from the second-guide driving mechanism.
When the folding processing is not to be performed with respect to a sheet S, the first guide G1 is held separate from the first folding nip FN1. When the first guide G1 is separate from the first folding nip FN1, the first guide G1 guides a sheet S that is being conveyed along the first conveyance path P1 toward the main discharge port 101. With the first guide G1 separate from the first folding nip FN1, the sheet S is not pulled into the first folding conveyance path FP1 from the first conveyance path P1. On the other hand, when the folding processing is to be performed with respect to the sheet S, the first guide G1 moves in the direction approaching the first folding nip FN1. A detailed description will be given later.

<Z-Folding of Sheet>

Hereinafter, with reference to FIGS. 10 to 12, a description will be given of the folding processing performed by the folding section 1. In the folding processing described below, a sheet is Z-folded.
First, when the folding processing is not to be performed with respect to a sheet S, the first guide G1 is held separate from the first folding nip FN1 (see FIG. 10). When the first guide G1 is separate from the first folding nip FN1, the first guide G1 guides a sheet S that is being conveyed along the first conveyance path P1 toward the main discharge port 101. That is, the sheet S is not pulled from the first conveyance path P1 into the first folding conveyance path FP1. In this manner, the sheet S is loaded onto the processing tray 3 without being subjected to the folding processing. Or, the sheet S is not loaded onto the processing tray 3 but is discharged to be loaded onto the main tray T1 or the sub tray T2.
On the other hand, when the folding processing is to be performed with respect to the sheet S, first, the first guide G1 is held separate from the first folding nip FN1 and the second guide G2 is held separate from the second folding nip FN2 (see FIG. 10). Then, the folding roller train 10 is driven. Further, the first switchback roller pair 11 and the second switchback roller pair 12 are both driven. At this time, the first switchback roller pair 11 and the second switchback roller pair 12 each rotate forward.
As a result, the sheet S is conveyed toward the intermediate roller pair 20 (that is, the main discharge port 101), a part of the sheet S corresponding to the first fold F1 (see FIG. 9) reaches the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1. When the part of the sheet S corresponding to the first fold F1 reaches the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1, the folding roller train 10 and the first switchback roller pair 11 both stop being driven.
Then, the folding roller train 10 starts being driven again, and the first switchback roller pair 11 also starts being driven again. Here, however, the first switchback roller pair 11 rotates backward. In this manner, a sag is generated in the sheet S between the conveyance nip N0 and the first switchback nip SN1 (that is, at the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1). Further, after the part of the sheet S corresponding to the first fold F1 has reached the branching position at which the first folding conveyance path FP1 branches off from the first conveyance path P1, the first guide G1 moves in the direction approaching the first folding nip FN1, and is held close to the first folding nip FN1.
In this manner, as shown in FIG. 11, the sheet S is pulled from the first conveyance path P1 into the first folding conveyance path FP1. Specifically, the sagged part of the sheet S between the conveyance nip N0 and the first switchback nip SN1 is pulled into the first folding nip FN1. At this time, since the folding roller train 10 is being driven, the part of the sheet S that has been pulled into the first folding nip FN1 passes through the first folding nip FN1. In this manner, the first fold F1 is formed in the sheet S.
Then, the part of the sheet S where the first fold F1 has been formed reaches the second switchback nip SN2. Thereafter, the part of the sheet S corresponding to the second fold F2 (see FIG. 9) reaches the branching position at which the second folding conveyance path FP2 branches off from the first folding conveyance path FP1 (that is, a position on the first folding conveyance path FP1 between the first folding nip FN1and the second switchback nip SN2). When the part of the sheet S corresponding to the second fold F2 has reached the branching position at which the second folding conveyance path FP2 branches off from first folding conveyance path FP1, the folding roller train 10 and the second switchback roller pair 12 each stop being driven.
Then, the folding roller train 10 starts being driven again, and the second switchback roller pair 12 also starts being driven again. Here, however, the second switchback roller pair 12 rotates backward. In this manner, a bend is generated in the sheet S between the first folding nip FN1 and the second switch-back nip SN2 (that is, at the branching position at which the second folding conveyance path FP2 branches off from the first folding conveyance path FP1). Further, after the part of the sheet S corresponding to the second fold F2 has reached the branching position at which the second folding conveyance path FP2 branches off from the first folding conveyance path FP1, the second guide G2 moves in the direction approaching the second folding nip FN2, and is held close to the second folding nip FN2.
In this manner, as shown in FIG. 12, the sheet S is pulled from the first folding conveyance path FP1 into the second folding conveyance path FP2. Specifically, the bent part of the sheet S between the first folding nip FN1 and the second switchback nip SN2 is pulled into the second folding nip FN2. At this time, since the folding roller train 10 is being driven, the part of the sheet S that has been pulled into the second folding nip FN2 passes through the second folding nip FN2. In this manner, the second fold F2 is formed in the sheet S. That is, a Z-folded sheet Sz is obtained.
At this time, the folding roller train 10 is continuously being driven. That is, the Z-folded sheet Sz is conveyed along the second folding conveyance path FP2. In this manner, the Z-folded sheet Sz is fed into the first conveyance path P1 from the joining position at which the second folding conveyance path FP2 joins the first conveyance path P1, and the Z-folded sheet Sz is conveyed toward the nip of the intermediate roller pair 20.
At this time, the intermediate roller pair 20 is being driven. Thus, after the Z-folded sheet Sz has reached the intermediate roller pair 20, the Z-folded sheet Sz is conveyed by the intermediate roller pair 20 toward the main discharge port 101. The Z-folded sheet Sz is loaded onto the processing tray 3, subjected to the predetermined post-processing, and then discharged through the main discharge port 101 to be loaded onto the main tray T1. Note that, in a case where no predetermined post-processing is to be performed, the Z-folded sheet Sz is not loaded onto the processing tray 3, but is discharged through the main discharge port 101 to be loaded onto the main tray T1.

Hereinafter, with reference to FIGS. 13 to 17, a description will be given of a process performed by the pull-in member 4 to load a sheet S onto the processing tray 3. In the following description, a sheet S that is not Z-folded is denoted by a symbol Sn and referred to as a non-folded sheet Sn.
In a state in which a sheet S is placed on the processing tray 3, the front end part of the sheet S (in other words, a downstream part of the sheet S in the sheet conveyance direction) protrudes beyond the processing tray 3 via the main discharge port 101 so as to be positioned above the main tray T1. When loading a sheet S onto the processing tray 3, without any measures taken, the front end part of the sheet S protruding so as to be positioned above the main tray T1 would hang down.
To prevent this, the control section 7 controls the position of the support member 5. The control section 7 protrudes or retracts the support member 5 as necessary.
When loading a sheet S onto the processing tray 3 in a state in which no sheet S is placed on the processing tray 3, the control section 7 moves the support member 5 from the retraction position to the protrusion position. That is, when the sheet S that is to be loaded onto the processing tray 3 this time is a first sheet S to be loaded onto the processing tray 3, the control section 7 moves the support member 5 from the retraction position to the protrusion position. The support member 5 protrudes the support portion 50 above the main tray T1. The support portion 50 makes contact with a lower surface of the sheet S.
In this manner, the portion of the sheet S on the processing tray 3 protruding via the main discharge port 101 so as to be positioned above the main tray T1 is supported by the support portion 50 from below. As a result, it becomes possible to prevent hanging-down of the front end part of the sheet S protruding so as to be positioned above the main tray T1.
When no sheet S is placed on the processing tray 3, regardless of whether the first sheet S to be loaded onto the processing tray 3 this time is a Z-folded sheet Sz, the support member 5 moves from the retraction position to the protrusion position when the first sheet S is loaded onto the processing tray 3. In a case where the first sheet S is a non-folded sheet Sn, as shown in FIG. 13, the front end part of the non-folded sheet Sn is supported by the support member 5 from below. In a case where the first sheet S is a Z-folded sheet Sz, as shown in FIG. 14, the front end part of the Z-folded sheet Sz is supported by the support member 5 from below.
On the other hand, when a sheet S is loaded onto the processing tray 3 in a state in which a sheet S has already been loaded on the processing tray 3, depending on whether the sheet S to be newly loaded onto the processing tray 3 is a Z-folded sheet Sz, the position of the support member 5 is changed. Note that the control unit 7 is capable of recognizing whether each of the sheet S that has already been loaded on the processing tray 3 and the sheet S that is to be newly loaded onto the processing tray 3 is a Z-folded sheet Sz, based on job information.
First, a description will be given of a state in which only a non-folded sheet Sn has already been loaded on the processing tray 3 (that is, a state in which no Z-folded sheet Sz is placed on the processing tray 3). Note that if a non-folded sheet Sn has already been loaded on the processing tray 3, it indicates that the support member 5 has been moved to the projected position.
When a sheet S is newly loaded onto the processing tray 3 in a state in which only a non-folded sheet Sn has already been loaded on the processing tray 3, if the sheet S to be newly loaded onto the processing tray 3 this time is a Z-folded sheet Sz, the control section 7 moves the support member 5 from the protrusion position to the retraction position. In this manner, in the case where the sheet S to be newly loaded onto the processing tray 3 this time is a Z-folded sheet Sz, as shown in FIG. 15, with the support member 5 located at the retraction position, the Z-folded sheet Sz is loaded onto the processing tray 3 to be placed on top of the non-folded sheet Sn. On the other hand, when the sheet S that is to be newly loaded onto the processing tray 3 this time is a non-folded sheet Sn, the control section 7 holds the support member 5 at the protrusion position. In this manner, in the case where the sheet S to be newly loaded onto the processing tray 3 this time is a non-folded sheet Sn, although not illustrated, with the support member 5 located at the protrusion position, the non-folded sheet Sn is loaded onto the processing tray 3 to be placed on top of the non-folded sheet Sn.
Next, a description will be given of a state in which a Z-folded sheet Sz has already been loaded on the processing tray 3. Here, assume it is just one Z-folded sheet Sz that has already been loaded on the processing tray 3. This state corresponds to the states shown in FIGS. 14 and 15, for example. In this state, the support member 5 has been moved to the protrusion position.
Note that the state in which a Z-folded sheet Sz has already been loaded on the processing tray 3 also encompasses a state in which a non-folded sheet Sn is placed on top of a Z-folded sheet Sz placed on the processing tray 3. That is, a state is also encompassed in which a Z-folded sheet Sz and a non-folded sheet Sn are stacked in this order on the processing tray 3.
When a non-folded sheet Sn is newly loaded onto the processing tray 3 in a state in which a Z-folded sheet Sz has already been loaded on the processing tray 3, the control section 7 holds the support member 5 at the protrusion position. As a result, although not illustrated, with the support member 5 located at the protrusion position, the non-folded sheet Sn is loaded on top of the Z-folded sheet Sz placed on the processing tray 3.
Note that, in a Z-folded sheet Sz, the front end part thereof that is Z-folded is thick. Thus, in a state in which a Z-folded sheet Sz is placed on the processing tray 3, the thick portion (i.e., the Z-folded portion) of the Z-folded sheet Sz is positioned at the main discharge port 101. That is, a state is achieved in which the thick portion of the Z-folded sheet Sz is positioned between the upper roller 21 and the lower roller 22 of the discharge roller pair 2 in the up-down direction.
Accordingly, in the state in which the Z-folded sheet Sz has already been loaded on the processing tray 3 (see FIG. 14), an apparent opening width (the opening width being a width in the up-down direction) of the main discharge port 101 becomes narrower than in the state in which the Z-folded sheet Sz is not placed on the processing tray 3 (see FIG. 13). Note that, in FIG. 13, the apparent opening width of the main discharge port 101 is denoted by a symbol W1, and that, in FIG. 14, the apparent opening width of the main discharge port 101 is denoted by W2.
In a case of loading a Z-folded sheet Sz onto the processing tray 3 in the state in which the apparent opening width of the main discharge port 101 is reduced in the up-down direction, when the front end part of the Z-folded sheet Sz is protruded from the main discharge port 101 so as to be positioned above the main tray T1, the front end part of the Z-folded sheet Sz tends to be caught on the discharge roller pair 2 (specifically, the upper roller 21).
If the front end part of the Z-folded sheet Sz becomes caught on the discharge roller pair 2, a rear end of the Z-folded sheet Sz is prevented from reaching the reference plate 30, and thus the Z-folded sheet Sz is displaced from its proper position on the processing tray 3. Further, the Z-folded sheet Sz caught on the discharge roller pair 2 may prevent conveyance of a next sheet S, thereby causing a jam error.
To prevent such inconvenience, in the present embodiment, when a Z-folded sheet Sz is newly loaded onto the processing tray 3 in a state in which a sheet S has already been loaded on the processing tray 3, the control section 7 moves the support member 5 from the protrusion position to the retraction position. Specifically, regardless of whether the sheet S already loaded on the processing tray 3 is a Z-folded sheet Sz or a non-folded sheet Sn (that is, even when it is only a non-folded sheet Sn that has already been loaded on the processing tray 3), the control section 7 moves the support member 5 from the protrusion position to the retraction position. The state in which a Z-folded sheet Sz has already been loaded on the processing tray 3 is shown in FIG. 16. Illustration is omitted of a state after the support member has been moved when it is only a non-folded sheet Sn that has already been loaded on the processing tray 3. Further, although not illustrated, when a Z-folded sheet Sz is newly loaded onto the processing tray 3 in a state in which a Z-folded sheet Sz and a non-folded sheet Sn are stacked in a mixed manner on the processing tray 3, the control section 7 also moves the support member 5 from the protrusion position to the retraction position.
Then, with the support member 5 in a state in which it has been moved from the protrusion position to the retraction position, the control section 7 newly loads a Z-folded sheet Sz onto the processing tray 3. In this manner, in the case where the sheet S that has already been loaded on the processing tray 3 is a Z-folded sheet Sz, the state shown in FIG. 17 is achieved.
With this configuration, since the support member 5 has been moved from the protrusion position to the retraction position, as shown in FIGS. 16 and 17, in the Z-folded sheet Sz placed on the processing tray 3, the front end part thereof protruding via the main discharge port 101 so as to be positioned above the main tray T1 hangs down. In the case where the front end part of the Z-folded sheet Sz placed on the processing tray 3 is hanging down, the apparent opening width of the main discharge port 101 becomes wider than in a case where the front end part is not hanging down. That is, it is possible to prevent reduction of the apparent opening width of the main discharge port 101.
By avoiding reducing the apparent opening width of the main discharge port 101, even in a case where a Z-folded sheet Sz is newly loaded onto the processing tray 3 in a state in which a sheet S has already been loaded on the processing tray 3 (here, the sheet S may be a Z-folded sheet Sz or a non-folded sheet Sn, or both a Z-folded sheet Sz and a non-folded sheet Sn may be placed in a mixed manner on the processing tray 3), it is possible to prevent the front end part of the Z-folded sheet Sz that is to be newly loaded onto the processing tray 3 from becoming caught on the discharge roller pair 2. In this manner, it is possible to bring the rear end of the Z-folded sheet Sz into contact with the reference plate 30. In other words, it is possible to normally perform positioning of the Z-folded sheet Sz on the processing tray 3. As a result, it becomes possible to prevent misalignment of a plurality of sheets S, including a Z-folded sheet S, stacked on the processing tray 3.
Note that the front end part of a Z-folded sheet Sz has become stiff by being Z-folded. Thus, even when the support member 5 is moved from the protrusion position to the retraction position, the Z-folded front end part (in other words, the stiff part) of the Z-folded sheet Sz exerts a function similar to that of the support portion 50.
Further, in the present embodiment, with the support member 5 located at the retraction position, when loading a bundle of sheets S stacked on the processing tray 3 onto the main tray T1, the control section 7 moves the support member 5 from the retraction position to the protrusion position. In other words, in a state in which a bundle of sheets S including a plurality of (two or more) Z-folded sheets Sz are stacked on the processing tray 3, when loading the bundle of sheets S stacked on the processing tray 3 onto the main tray T1, the control section 7 moves the support member 5 from the retraction position to the protrusion position.
In this manner, the front end parts of the sheets S stacked on the processing tray 3 are moved upward to be further separate from the main tray T1. As a result, it becomes possible to prevent the front end of a sheet S placed on the processing tray 3 from becoming caught on the main tray T1 when the bundle of sheets S stacked on the processing tray 3 is discharged through the main discharge port 101 to be loaded onto the main tray T1.
Moreover, in the present embodiment, when loading a sheet S onto the processing tray 3 in a state in which no sheet S is placed on the processing tray 3, the control section 7 moves the support member 5 from the retraction position to the protruding position regardless of whether the sheet S that is to be loaded onto the processing tray 3 this time is a Z-folded sheet Sz. In the state in which no sheet S is placed on the processing tray 3, the apparent opening width of the main discharge port 101 is not reduced. Thus, even in a state in which the support member 5 has been moved from the retraction position to the protrusion position, a Z-folded sheet Sz does not become caught on the discharge roller pair 2.

Claims

A sheet post-processing apparatus (100), comprising:
a discharge port (101) through which a sheet (S) is discharged;

a discharge section (2) that conveys the sheet (S) and discharged the sheet (S) through the discharge port (101);

a discharge tray (T1) onto which the sheet (S) discharged through the discharge port (101) is loaded;

a processing tray (3) that is disposed upstream of the discharge port (101) in a sheet conveyance direction and onto which the sheet (S) is loaded to be subjected to predetermined post-processing;

a folding section (1) that performs, as post-processing, folding processing to Z-fold the sheet (S) and that conveys a Z-folded sheet (Sz), which is obtained by subjecting the sheet (S) to the folding processing, toward the processing tray (3);

a support member (5) that includes a support portion (50) supporting, from below, a part of the sheet (S) placed on the processing tray (3), said part protruding via the discharge port (101) so as to be positioned above the discharge tray (T1), and that is movable between a protrusion position at which the support portion (50) protrudes from an upstream side of the discharge port (101) in the sheet conveyance direction so as to be positioned above the discharge tray (T1) and a retraction position at which the support portion (50) is retracted to a position upstream of the discharge port (101) in the sheet conveyance direction; and

a control section (7) that controls a position of the support member (5),
wherein

when newly loading the Z-folded sheet (Sz) onto the processing tray (3) in a state in which a sheet (S) is placed thereon, the control section (7) moves the support member (5) from the protrusion position to the retraction position.
The sheet post-processing apparatus (100) according to claim 1,
wherein
when loading a bundle of sheets (S) stacked on the processing tray (3) onto the discharge tray (T1) in a state in which the support member (5) is located at the retraction position, the control section (7) moves the support member (5) from the retraction position to the protrusion position.
The sheet post-processing apparatus (100) according to claim 1 or 2,
wherein
when loading the sheet (S) onto the processing tray (3) in a state in which no sheet (S) is placed on the processing tray (3), regardless of whether the sheet (S) that is to be loaded onto the processing tray (3) this time is the Z-folded sheet (Sz), the control section (7) moves the support member (5) from the retraction position to the protrusion position.
An image forming system (100S), comprising:
the sheet post-processing apparatus according to any one of claims 1 to 3; and

an image forming apparatus (200) that prints an image on the sheet (S) and that feeds the sheet (S) printed to the sheet post-processing device (100).