Sheet loading device, and image forming system

Abstract

To provide: a sheet loading device capable of receiving the following sheet during alignment with a pair of aligning plates 401, 402; and an image forming system.SOLUTION: A first tray 49 loads a sheet, and moves downward according to a load of the sheet. A discharge roller pair 42 conveys the sheet toward the first tray 49. A pair of aligning plates 401, 402 act on both end edges of a sheet bundle in a width direction to align the sheet bundle loaded on the first tray 49. A guide face 4002 permits temporarily receiving the following sheet at an upper portion of the first tray 49, when the pair of aligning plates 401, 402 align the sheet bundle.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to a sheet loading device for loading sheets and an image forming system including the sheet loading device.

Background Art

[0002] Patent Document 1 discloses a configuration of a sheet loading device including a liftable loading tray and an alignment member that aligns the width direction of the sheet discharged onto the loading tray on the loading tray. In the case of the configuration described in Patent Document 1, every time a sheet is loaded onto the loading tray, the alignment member is moved in the width direction to align the sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, improvement in the productivity of devices has been demanded. When productivity is increased, the interval between the sheets continuously discharged onto the loading tray becomes narrow. As described in Patent Document 1, every time a sheet is loaded onto the loading tray, if the alignment member is moved in the width direction to align the sheet, there is a risk that the second sheet starts to be discharged onto the loading tray during the alignment of the first sheet and the second sheet collides with the alignment member during alignment.

[0005] An object of the present invention is to provide a sheet loading device and an image forming system capable of receiving the next sheet during alignment by the alignment member.

Means for Solving the Problems

[0006] One aspect of the present invention is a sheet loading device including a loading tray for loading sheets, a lowering unit for lowering the loading tray according to the loading of sheets, a conveying unit for conveying a sheet toward the loading tray, a first acting unit and a second acting unit that act on both end edges in the width direction of a sheet bundle to align the sheet bundle loaded on the loading tray, and an allowing unit that allows temporary acceptance of the next sheet above the loading tray when the first acting unit and the second acting unit are aligning the sheet bundle.

[0007] One aspect of the present invention is an image forming system including an image forming unit that forms an image on a sheet, a loading tray for loading the sheet on which the image is formed by the image forming unit, a lowering unit for lowering the loading tray according to the loading of sheets, a conveying unit for conveying a sheet toward the loading tray, a first acting unit and a second acting unit that act on both end edges in the width direction of a sheet bundle to align the sheet bundle loaded on the loading tray, and an allowing unit that allows temporary acceptance of the next sheet above the loading tray when the first acting unit and the second acting unit are aligning the sheet bundle.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a sheet loading device and an image forming system that can accept the next sheet during alignment by an alignment member.

Brief Description of the Drawings

[0009]

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Best Mode for Carrying Out the Invention

[0010] <First Embodiment> The first embodiment will be described with reference to FIGS. 1 to 31. First, the schematic configuration of the image forming system of this embodiment will be described with reference to FIG. 1.

[0011] [Image Forming System] In this embodiment, a copying machine is used as the image forming apparatus, and a sheet processing apparatus is connected to the opening of the sheet of this copying machine. The image forming system 1000 includes an image forming apparatus A and a sheet processing apparatus B. The sheet S on which an image is formed by the image forming apparatus A is received by the downstream sheet processing apparatus B, and is subjected to predetermined processing such as binding processing as necessary, and then sent to the downstream sending unit. The image forming apparatus A includes various structures such as, for example, a copying machine, a printer, a printing machine, a facsimile machine, and a multifunction machine having a plurality of these functions. Hereinafter, the image forming apparatus A and the sheet processing apparatus B will be described in detail. In the following description, for the image forming apparatus A and the sheet processing apparatus B, the side where an operator such as a user operates the apparatus (for example, the side where an operation panel or operation buttons are provided) is referred to as the front side (the front side of the paper surface in FIGS. 1, 2, etc.), and the side opposite to the front side is referred to as the rear side (the back side of the paper surface in FIGS. 1, 2, etc.).

[0012] [Image Forming Apparatus] As shown in FIG. 1, the image forming apparatus A includes an image forming unit A1, an image reading unit A2, and a document feeding unit A3. The image forming unit A1 includes a feeding unit 2, an image forming unit 3, a discharging unit 4, and a data processing unit 5 in the apparatus housing 1.

[0013] The sheet feeding unit 2 includes a plurality of cassettes 2a, 2b, and 2c, and each cassette 2a, 2b, 2c can store sheets S of different standard sizes selected in advance. The sheet S is, for example, paper, a plastic sheet, or the like. Each cassette 2a, 2b, 2c incorporates a separating mechanism for separating the internal sheets S one by one and a feeding mechanism for feeding out the sheets S. The sheet S stored in the sheet feeding unit 2 configured as described above feeds out the sheet S of the size designated by the control unit 310 (Fig. 3) of the image forming apparatus A to the feeding path 6. The feeding path 6 is provided with a conveying roller 7 for conveying the sheets S supplied from the plurality of cassettes 2a, 2b, 2c to the downstream side, and a registration roller pair 8 arranged at the path end for aligning the leading edges of the sheets S. The sheet S aligned at the leading edge by the registration roller pair 8 is fed to the downstream image forming unit 3 at a predetermined timing.

[0014] A large-capacity cassette 2d and a manual feed tray 2e are connected to the feeding path 6. The large-capacity cassette 2d is composed of an optional unit for storing sheets of a size that is consumed in large quantities. The manual feed tray 2e is configured to be able to supply special sheets such as thick paper sheets, coated sheets, and film sheets for which separation feeding is difficult.

[0015] The image forming unit 3 only needs to be configured to form an image on the sheet S sent from the sheet feeding unit 2, and various image forming mechanisms can be adopted. In the illustrated embodiment, an electrostatic image forming mechanism is shown as the image forming unit 3. However, the image forming unit 3 is not limited to the illustrated electrostatic image forming mechanism, and it is also possible to adopt an inkjet image forming mechanism, an offset image forming mechanism, or the like.

[0016] In the image forming unit 3 shown in Fig. 1, there are provided a photoreceptor 9 formed in a drum shape or a belt shape, and a light emitter 10 that emits an optical beam to the photoreceptor 9. A developing device 11 and a cleaner (not shown) are arranged around the rotating photoreceptor 9. The illustrated one is a monochrome printing mechanism. An electrostatic latent image is optically formed on the photoreceptor 9 by the light emitter 10, and toner is attached to this electrostatic latent image by the developing device 11. The toner image attached to the photoreceptor 9 is transferred onto the sheet S sent from the feeding unit 2 by the transfer charger 12. After the image-transferred sheet S is fixed by the fixing roller 13, it is sent to the transport path 14. Further, a circulation path is provided below the transport path 14 in the image forming unit 3. After the sheet S from the transport path 14 is reversed front to back by the switchback path, it is sent again to the registration roller pair 8, and an image is formed on the back surface of the sheet S and then sent to the transport path 14. A discharge roller 15 (so-called discharge roller) is arranged in the transport path 14, and an opening 16 is formed at the end thereof. The sheet S is sent out from the opening 16 to a sheet processing device B described later by the discharge roller 15.

[0017] An image reading unit A2 for optically reading a document image to be formed by the image forming unit 3 is provided above the image forming unit A1 configured as described above. A document feeding unit A3 is mounted further above the image reading unit A2.

[0018] The image reading unit A2 includes a first platen 17 and a second platen 21 formed of transparent glass, a reading carriage 18, a light source mounted on the reading carriage 18, a photoelectric conversion element 19, and a reduction optical system 20 configured by combining mirrors and lenses. Then, the reading carriage 18 is scanned along the first platen 17, the image of the document placed on the first platen 17 is irradiated with light from the light source, and the reflected light from the image of the document is guided to the photoelectric conversion element 19 by the reduction optical system 20 to read the image. The photoelectric conversion element 19 converts the image data into an electrical signal and transfers it to the image forming unit 3.

[0019] The original document feeding unit A3 includes a feeding tray 22, a feeding path 23, and a stacking tray 24. It conveys the original documents placed on the feeding tray 22 one by one along the feeding path 23, passes them over the second platen 21, and sends them out to the stacking tray 24. When reading the original documents fed from the original document feeding unit A3 and passing over the second platen 21, the reading carriage 18 is pre-stopped below the second platen 21, and image data is generated from the images passing over the second platen 21.

[0020] [Overall Configuration of the Sheet Processing Device] Next, the overall configuration of the sheet processing device B that performs processing such as stapling and folding on the sheets sent from the image forming device A will be described with reference to FIG. 2. FIG. 2 shows the detailed configuration of the sheet processing device B. The sheet processing device B can stack the sheets received from the receiving portion 26, which is the entrance of the straight path 28 connected to the opening 16 of the image forming device A, after processing, onto the first tray (first stacking tray) 49, the saddle stacking unit 131, and the second tray (second stacking tray) 71, which will be described later. Among the sheet processing device B, the portion other than the first tray 49 and the second tray 71 is defined as the processing unit 200. That is, the processing unit 200 includes the device housing 27, the straight path 28, the processing unit B1, and the saddle portion B2, which will be described later.

[0021] In the illustrated device, the sheets sent to the straight path 28 as the conveyance path and the first conveyance path are transferred from the processing unit B1, which will be described later, to the first tray 49 and the second tray 71, and from the saddle portion B2, which will be described later, to the saddle stacking unit 131. Each device has a control unit, a communication unit, etc., like the blocks showing the control configuration in the entire device shown in FIG. 3, and controls the device accordingly.

[0022] The processing unit B1 is disposed below the path exit (delivery unit 35) of the straight path 28, and collates and stacks a plurality of sheets sequentially delivered from the straight path 28 via the delivery unit 35 to form a sheet bundle, and can perform a binding process, which is an example of a predetermined process, on the end of this sheet bundle. The bound sheet bundle is loaded onto the first tray 49 as a loading unit.

[0023] The saddle unit B2 is disposed below the delivery unit of the saddle path 32 as the second conveyance path branching vertically downward from the straight path 28, collates and stacks a plurality of sheets sequentially delivered from the straight path 28 via the saddle path 32 and the delivery unit to form a sheet bundle, performs a saddle-stitching process, or performs a folding process without performing the saddle-stitching process, and then sends it out to the saddle loading unit 131. Hereinafter, each configuration will be described in detail.

[0024] [Device housing] As shown in FIG. 2, the sheet processing apparatus B includes a device housing 27, a straight path 28, a processing unit B1, a saddle unit B2, a first tray 49 as a loading tray, a saddle loading unit 131, a second tray 71, and the like. The straight path 28, the processing unit B1, and the saddle unit B2 are disposed inside the device housing 27. The straight path 28 has a sheet receiving portion 26 and a sheet delivery portion 35. The processing unit B1 and the saddle unit B2 process the sheets delivered from the delivery portion 35 of the straight path 28. The first tray 49, the saddle loading unit 131, and the second tray 71 load the sheets sent from each processing unit. The illustrated device housing 27 is connected to the device housing 1 of the image forming apparatus A located on the upstream side in the sheet conveyance direction in the straight path 28. The device housing 27 and the device housing 1 are arranged such that the height from the installation surface of the opening 16 of the image forming apparatus A and the receiving portion 26 of the sheet processing apparatus B is substantially the same, and the opening 16 and the receiving portion 26 are connected.

[0025] [Sheet receiving path] As shown in FIGS. 2 and 4, the straight path 28, which is a sheet receiving path, is configured as a substantially straight path that traverses the apparatus housing 27 in a substantially horizontal direction, and includes a receiving portion 26 that is continuous with an opening (main body opening) 16 of the image forming apparatus A, and a delivery portion 35 that is located on the opposite side across the apparatus from the receiving portion 26. In this straight path 28, sheet conveyance is possible in a first direction from the receiving portion 26 toward the first discharge path 31, and conveyance is also possible in a second direction from the first discharge path 31 toward the receiving portion 26. An entrance roller 29, a first conveyance roller 201, a second conveyance roller (shift roller) 202, and a third conveyance roller (shift roller) 203, which are conveyance rollers, are arranged. That is, the entrance roller 29, the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203 can convey a sheet in a first direction and a second direction opposite to the first direction in the conveyance path, and are arranged in order from the receiving portion 26 side with respect to the first direction.

[0026] Note that the second conveyance roller 202 and the third conveyance roller 203 are also shift rollers that can move a sheet in the width direction (front-rear direction) of the sheet that intersects the sheet conveyance direction. That is, the second conveyance roller 202 and the third conveyance roller 203 can be moved in the width direction by a drive unit (not shown), and can shift the sheet to the front side or the rear side while sandwiching the sheet.

[0027] The first discharge path 31 is connected to the delivery portion 35 of the straight path 28, and a pre-processing roller 36 as a conveyance portion is arranged at this connection portion. The sheet received from the straight path 28 and delivered to the first discharge path 31 and sent out from the first discharge path 31 is sent out to the first tray 49 or guided to the processing unit B1. Note that each of the above-described conveyance rollers may be another member capable of conveying a sheet, such as a conveyance belt.

[0028] [Layout of Sheet Receiving Path] As shown in FIGS. 2 and 4, a saddle path 32 which is a branch path and an upper conveyance path 30 are connected to the straight path 28. The saddle path 32 and the upper conveyance path 30 are arranged in order from the receiving portion 26 toward the first discharge path 31 with respect to the first direction. Further, the saddle path 32 branches downward in the vertical direction from the straight path 28, and the upper conveyance path 30 branches upward in the vertical direction from the straight path 28. At each branching portion between the straight path 28 and the saddle path 32 and the upper conveyance path 30, a saddle path switching member 33 and an upper conveyance path switching member 34 are arranged as switching members for switching the conveyance direction of the conveyed sheet.

[0029] Note that a buffer path 39 which is a branch path branching downward in the vertical direction from the straight path 28 is connected between the second conveyance roller 202 and the third conveyance roller 203. The buffer path 39 as a buffer portion is a path capable of temporarily waiting for the sheet. When buffering the sheet in the buffer path 39, the sheet conveyed to the downstream side in the first direction from the branching portion of the buffer path 39 of the straight path 28 is conveyed in the direction opposite to the first direction by reversely rotating the third conveyance roller 203 or the like, and is guided to the buffer path 39 by a switching member (not shown).

[0030] Then, this sheet is conveyed to the buffer path 39 by the conveyance roller 208, and the rotation of the conveyance roller 208 is stopped at a position where the rear end of the sheet has passed through the straight path 28. In this state, the next sheet can be conveyed to the downstream side in the first direction from the branching portion of the buffer path 39 in the straight path 28. Further, in the present embodiment, by reversely rotating the conveyance roller 208, the sheet in the buffer path 39 can be conveyed toward the straight path 28, and the sheet and the next sheet can be merged at the branching portion. Furthermore, these two sheets can be stacked and conveyed by the third conveyance roller 203 and the pre-processing roller 36 as a buffer conveyance unit.

[0031] [Branching of Paths] The upper conveyance path switching member 34 is composed of a switching member guide that moves to change the conveyance path so as to convey the sheet received from the receiving portion 26 to either the first discharge path 31 or the upper conveyance path 30, and is connected to a drive portion (not shown) such as an electromagnetic solenoid or a mini motor.

[0032] [Upper conveyance path] The straight path 28 is connected to an upper conveyance path 30 (printout discharge path) that conveys sheets other than the sheets discharged to the first discharge path 31, and the path branching portion is provided with an upper conveyance path switching member 34 for guiding the sheet to the upper conveyance path 30. Further, the upper conveyance path 30 is provided with a fourth conveyance roller 204, a fifth conveyance roller 205, a sixth conveyance roller 206 as conveyance rollers for guiding the sheet to the second tray 71, and a second discharge roller pair 207 as a discharge portion. By these, the sheet guided to the upper conveyance path 30 is sent out from the upper conveyance path opening 40 to the second tray 71 (overflow tray) as a stacking tray (stacking portion) by the second discharge roller pair 207.

[0033] The processing unit B1 is disposed on the downstream side of the straight path 28, and includes a processing tray 37 as a placement portion for placing the sheets sent from the first discharge path 31 and aligning and stacking the plurality of placed sheets, and a binding processing mechanism (stapler) 47 as a processing portion for binding the stacked sheet bundle. Then, the processing unit B1 performs a binding process on the sheet bundle placed on the processing tray 37. The binding processing mechanism 47 is disposed vertically below the straight path 28. The binding processing mechanism 47 is movable in the width direction and can perform a binding process at a desired position in the width direction with respect to the sheet bundle placed on the processing tray 37. As shown in FIGS. 2 and 4, the first discharge path 31 forms a step, and the processing tray 37 is disposed below the step. A first switchback path is formed between the first discharge path 31 and the processing tray 37 to reverse the conveyance direction from the opening 31a of the first discharge path 31 and guide the sheet onto the processing tray 37.

[0034] Specifically, the first discharge path 31 is provided with an upper conveyance roller 41 and a lower conveyance roller 48 that sandwich and convey the sheet. The upper conveyance roller 41 and the lower conveyance roller 48 constitute a discharge roller pair 42 as a discharge unit. The upper conveyance roller 41 can come into contact with and separate from the lower conveyance roller 48, and can convey in the direction (discharge direction) toward the first tray 49 with the upper conveyance roller 41 and the lower conveyance roller 48 sandwiching the sheet, and in the direction opposite to this direction. And, it can be conveyed by the upper conveyance roller 41 and the lower conveyance roller 48 through the first switchback path toward the processing tray 37. Further, the upper conveyance roller 41 and the lower conveyance roller 48 (that is, the discharge roller pair 42) send out the sheet or the sheet bundle on the processing tray 37 from the opening 31a to the first tray 49 as a stacking tray (stacking unit). The opening 31a is a portion opened above the lower conveyance roller 48 of the apparatus housing 27. Furthermore, the discharge roller pair 42 sends out the sheet conveyed to the first discharge path 31 without passing through the processing tray 37 from the opening 31a to the first tray 49.

[0035] The processing unit B1 has a rear end regulating portion 47a as a butting portion that abuts against the end portion (rear end) of the sheet to position the sheet. On the processing tray 37, a scraping-in portion 38 is arranged to convey the sheet conveyed to the processing tray 37 by the upper conveyance roller 41 and the lower conveyance roller 48 toward the rear end regulating portion 47a. And, the binding processing mechanism 47 performs a binding process on the end portion of a sheet bundle composed of a plurality of sheets placed on the processing tray 37 and whose end position is regulated by the rear end regulating portion 47a. Further, the binding processing mechanism 47 has a sheet bundle unloading mechanism that unloads this sheet bundle to the first tray 49 after performing the binding process on the end portion of the sheet bundle.

[0036] The processing unit B1 also includes a pair of alignment plates 270 as shift members, a rear-end dropping member 44 as a sheet dropping portion, and a sheet discharging member 45. The pair of alignment plates 270 move in the width direction (shift direction) of the sheet that intersects the first direction while being in contact with the edge along the conveyance direction (first direction) of the sheet placed on the processing tray 37, thereby moving the sheet conveyed by the pre-processing roller 36 in the width direction. Such a pair of alignment plates 270 are arranged to face each other in the width direction. Further, the pair of alignment plates 270 perform alignment in the width direction of the sheet by moving in the width direction and coming into contact with the widthwise edges of the sheet. Among the pair of alignment plates 270, the front-side alignment plate 270 is moved in the width direction by the alignment plate 1 moving motor M13, and the rear-side alignment plate 270 is moved in the width direction by the driving of the alignment plate 2 moving motor MT14, respectively.

[0037] The rear-end dropping member 44 is disposed above the processing tray 37 and moves in the vertical direction to abut against the upper surface on the upstream side in the conveyance direction of the sheet, and operates to drop the upstream end portion (rear end portion) of the sheet toward the processing tray 37. The sheet discharging member 45 discharges the sheet bundle placed on the processing tray 37 to the first tray 49 by pushing the rear end of the sheet bundle.

[0038] Note that the binding processing unit B1 shown in FIG. 2 supports the sheet sent from the first discharge path 31 so as to straddle between the processing tray 37 and the first tray 49 on its downstream side. That is, the sheet sent from the first discharge path 31 has its front end portion supported on the uppermost sheet of the first tray 49 on the downstream side and its rear end portion supported on the processing tray 37.

[0039] [Saddle path] A straight path 28 is connected to a saddle path 32 for conveying a sheet to the saddle portion B2 described above, and a saddle path switching member 33 for guiding the sheet to the saddle path 32 is provided at the path branching portion. The sheet guided to the saddle portion B2 by the saddle path 32 is sent to the saddle stacking unit 131 via the post-fold path guide 114, the second roller post-path guide 116, and the saddle discharge guide 124 in a substantially horizontal direction after being center-folded and folded. In the present embodiment, the saddle discharge guide 124 is used as an auxiliary guide for appropriately stacking the sheet on the saddle stacking unit 131.

[0040] [Control Configuration] The schematic of the control configuration of the image forming system 1000 will be described with reference to FIG. 3. First, the image forming apparatus A includes a control unit 310, an operation unit 302, a conveyance control unit 303, an image processing unit 304, a drive unit 305, and a communication unit 306. The control unit 310 includes a CPU (Central Processing Unit) 311, a ROM (Read Only Memory) 312, and a RAM (Random Access Memory) 313. The CPU 311 controls each unit while reading a program corresponding to the control procedure stored in the ROM 312. Also, work data and input data are stored in the RAM 313, and the CPU 311 controls with reference to the data stored in the RAM 313 based on the aforementioned program and the like.

[0041] The operation unit 302 is, for example, an operation panel provided on the image forming apparatus A connected to the control unit 310, and an operator operates the apparatus and makes various settings. The conveyance control unit 303 controls various conveyance rollers and switching members for switching conveyance paths for conveying a sheet in the image forming apparatus A. The image processing unit 304 controls the image forming unit 3. The drive unit 305 controls various motors and power supplies. The communication unit 306 communicably connects the control unit 310 to an external device 301 such as a personal computer and the communication unit 321 of the sheet processing apparatus B.

[0042] The sheet processing apparatus B includes a stacker control unit 330, a conveyance control unit 322, an end binding control unit 323, a discharge processing control unit 324, and a communication unit 321. Similar to the control unit 310, the stacker control unit 330 includes a CPU 331, a ROM 332, and a RAM 333. The conveyance control unit 322 controls various conveyance rollers that convey sheets and switching members that switch conveyance paths, except for the saddle unit B2 of the sheet processing apparatus B. The end binding control unit 323 controls the processing unit B1. The discharge processing control unit 324 controls the discharge of sheets and various stacking trays on which the discharged sheets are stacked. The communication unit 321 communicably connects the communication unit 306 of the image forming apparatus A and the communication unit 341 of the saddle unit B2 to the stacker control unit 330. Note that the communication between the communication unit 306 and the communication unit 321 may be performed by wired communication or wireless communication.

[0043] Note that the communication unit 321 functions as a notification unit, and as will be described later, when it is detected that there are sheets on stacking trays such as the first tray 49 and the second tray 71, it notifies that there are sheets. Specifically, it transmits information indicating that there are sheets to the communication unit 306 of the image forming apparatus A, and causes, for example, a display unit of the operation unit 302 to display that there are sheets.

[0044] The saddle unit B2 includes a saddle control unit 350, a conveyance control unit 342, a middle binding control unit 343, a middle folding control unit 344, and a communication unit 341. Similar to the control unit 310, the saddle control unit 350 includes a CPU 351, a ROM 352, and a RAM 353. The conveyance control unit 342 controls various conveyance rollers that convey sheets and switching members that switch conveyance paths in the saddle unit B2. The middle binding control unit 343 controls the middle binding processing unit 104. The middle folding control unit 344 controls the middle folding mechanism C1. The communication unit 341 communicably connects the communication unit 321 of the sheet processing apparatus B to the saddle control unit 350.

[0045] [Saddle Unit] As shown in FIG. 2, the saddle part B2 has a center folding processing mechanism C1. The center folding processing mechanism C1 aligns and stacks the sheets sent from the straight path 28 into a sheet bundle, performs binding processing on the central part in the conveyance direction of the sheet and the bundle, and performs center folding processing of bending the sheet bundle at the bound position. And a saddle loading unit 131 is arranged on the downstream side of the center folding processing mechanism C1 to store the sheet bundle after the bookbinding process. Note that it is also possible to perform only the center folding process of aligning and stacking one or a plurality of sheets and bending the central part in the conveyance direction without performing the center binding process.

[0046] [Sheet Loading Device] Details of the sheet loading device 400 included in the sheet processing device B of the present embodiment will be described with reference to FIGS. 5 to 13. The sheet loading device 400 stacks sheets that have been subjected to a predetermined process (in this embodiment, binding process) by a binding processing mechanism 47 as a processing unit or sheets that have not been subjected to a predetermined process. The sheet loading device 400 includes discharge roller pairs 42 (upper conveyance roller 41 and lower conveyance roller 48) as a conveyance unit (discharge unit), a first tray 49 as a loading tray, a tray lifting motor MT18 as a lowering unit (lifting unit), a pair of alignment plates (joggers) 401 and 402 as a first acting unit and a second acting unit (a pair of alignment members), a jogger 1 movement motor MT20 and a jogger 2 movement motor MT21 as an alignment member movement unit, and the like.

[0047] The tray lifting motor MT18 (Fig. 5) raises and lowers the first tray 49. The alignment plates 401 as the first acting part and the alignment plates 402 as the second acting part act on both end edges in the width direction of the sheet bundle to align the sheet bundle loaded on the first tray 49. That is, the pair of alignment plates 401 are located on both sides in the width direction of the sheet that intersects the discharge direction (conveying direction) of the sheet by the upper conveying roller 41 and the lower conveying roller 48 as a pair of conveying rollers with respect to the uppermost sheet loaded on the first tray 49, and perform alignment in the width direction of the uppermost sheet. The jogger 1 moving motor MT20 as the first moving part moves the front alignment plate 401 in the width direction. The jogger 2 moving motor MT21 as the second moving part moves the rear alignment plate 402 in the width direction. That is, in the present embodiment, the pair of alignment plates 401 and 402 can be independently moved in the width direction.

[0048] Here, the relationship between the drive motors of some components of the sheet processing apparatus B around the sheet stacking apparatus 400 and various sensors will be described with reference to the block diagram of Fig. 5. Various motors are controlled by the stacker control unit 330 as the control unit, and the signals of various sensors are sent to the stacker control unit 330. The stacker control unit 330 controls the driving of various motors based on the signals of various sensors.

[0049] First, the inlet conveying motor MT1 drives the inlet roller 29, the conveying motor MT2 drives the first conveying roller 201, the shift 1 conveying motor MT3 drives the second conveying roller (shift roller) 202, the shift 2 conveying motor MT4 drives the third conveying roller (shift roller) 203, and the pre-processing conveying motor MT5 drives the pre-processing roller 36. These are all motors that can be rotationally driven in both forward and reverse directions. Also, the discharge roller 1 motor MT6 is a motor that can rotationally drive the upper conveying roller 41 in both forward and reverse directions. Note that the discharge roller 1 motor MT6 also rotationally drives the paddle 275 described later. The discharge roller 2 motor MT7 is a motor that can rotationally drive the lower conveying roller 48 in both forward and reverse directions. The buffer conveying motor MT8 is a motor that can rotationally drive the conveying roller 208 that conveys the sheet in the buffer path 39 described above in both forward and reverse directions.

[0050] Also, the shift 1 motor MT9 is a motor that moves the second conveying roller 202, and the shift 2 motor MT10 is a motor that moves the third conveying roller 203 in the width direction. The discharge roller swing motor MT11 is a motor that swings the upper conveying roller 41 in the vertical direction so as to be able to contact and separate from the lower conveying roller 48 as described above. The rear end dropping drive motor MT12 is a motor that moves the rear end dropping member 44 in the vertical direction. The alignment plate 1 movement motor M13 and the alignment plate 2 movement motor MT14 are motors that move a pair of alignment plates 270 that align the sheet in the processing tray 37 in the width direction as described above.

[0051] Also, the stapler movement motor MT15 enables the stapling mechanism 47 to move in the width direction. The stapler motor MT16 is a motor that drives the stapling mechanism 47 to perform stapling processing. The bundle discharging motor MT17 is a motor that drives the bundle discharging member 45. The tray lifting motor MT18 is a motor that raises and lowers the first tray 49. The jogger lifting motor MT19 is a motor that raises and lowers a pair of alignment plates (joggers) 401, 402 as described later. In this embodiment, the alignment plates 401, 402 are raised and lowered by one motor, but the alignment plates 401, 402 may be raised and lowered by separate motors. The jogger 1 movement motor MT20 and the jogger 2 movement motor MT21 move the pair of alignment plates 401, 402 in the width direction respectively as described above. The paddle lifting motor MT22 is a motor that raises and lowers a paddle 275 described later.

[0052] Next, various sensors will be described. As shown in FIG. 4, the entrance sensor SN1 is provided at the entrance of the straight path 28 and detects a sheet delivered from a device (image forming apparatus A in this embodiment) connected to the upstream side of the sheet processing apparatus B to the sheet processing apparatus B. As shown in FIGS. 6 and 7, etc., the registration detection sensor SN2 is disposed on the upstream side in the conveyance direction of the second conveyance roller 202 which is a shift roller, and detects the position of the sheet in the width direction. As shown in FIG. 4, the sheet edge detection sensor SN3 is disposed on the upstream side in the conveyance direction of the pre-processing roller 36 and detects the sheet. The stacker control unit 330 determines that the rear end of the sheet has passed through the discharge roller pair 42 after a predetermined time has elapsed since the rear end of the sheet has passed through the sheet edge detection sensor SN3.

[0053] The shift roller 1HP detection sensor SN4 detects the home position (HP) regarding the width direction of the second conveyance roller 202. The shift roller 2HP detection sensor SN5 detects the home position (HP) regarding the width direction of the third conveyance roller 203. The jogger lift HP detection sensor SN6 detects the home position (HP) in the lift direction of the pair of alignment plates 401, 402. The jogger 1HP detection sensor SN7 detects the home position (HP) regarding the width direction of the front alignment plate 401. The jogger 2HP detection sensor SN8 detects the home position (HP) regarding the width direction of the rear alignment plate 402. As will be described later, the pair of alignment plates 401, 402 are each movable in the width direction. The home positions in the lift direction and the width direction of the pair of alignment plates 401, 402 are the positions shown in FIGS. 6 and 7.

[0054] The paddle lift HP detection sensor SN9 detects the home position (HP) of the paddle 275 in the lifting direction. The home position of the paddle 275 is the position shown in FIGS. 6 and 7. The sheet upper surface detection sensor SN10 detects the upper surface of the sheet on the first tray 49. In this embodiment, the sheet upper surface detection sensor SN10 also detects the presence or absence of a sheet on the first tray 49. The sheet removal detection sensor SN11 is a sensor for detecting that a stack of sheets is loaded on the first tray 49 and the stack of sheets has been suddenly removed while the first tray 49 is in the lowered state.

[0055] Next, with reference to FIGS. 6 and 7, the configuration from the first conveyance roller 201 to the first tray 49 of the sheet processing apparatus B will be described. FIGS. 6 and 7 are a cross-sectional view and a top view of a state in which the pair of alignment plates 401, 402 and the paddle 275 are in the home position. Since the configuration from the first conveyance roller 201 to the discharge roller pair 42 has been described above, hereinafter, the sheet loading device 400, which is the configuration around the first tray 49, will be described.

[0056] The first tray 49 loads the sheets discharged from the opening 31a of the first discharge path 31. Among the outer surfaces of the apparatus housing 27, below the opening 31a, between the first tray 49 and the processing unit B1, there is provided a butting member 271 against which the rear end (the upstream end in the discharge direction) of the discharged sheet abuts. This butting member 271 serves to align the conveyance direction of the sheets discharged and loaded on the first tray 49. The loading surface 49a, which is the upper surface of the first tray 49, gently slopes downward toward the butting member 271. That is, the loading surface 49a of the first tray 49 on which the sheets are loaded slopes at a first angle with respect to the horizontal direction so as to face upward as it goes toward the downstream side in the discharge direction. The sheets discharged from the opening 31a to the loading surface 49a slide down along the slope of the loading surface 49a after falling onto the first tray 49, and eventually the rear end of the sheet reaches the butting member 271 and stops.

[0057] The first tray 49 moves up and down in the vertical direction via a lifting mechanism (not shown) by a tray lifting motor MT18. That is, when discharging the sheets onto the first tray 49 or the second tray 71, it is necessary to lift or lower the first tray 49 or the second tray 71 so as to keep the alignment of the stacked sheets from deteriorating, i.e., to keep the loading surface 49a or the position of the uppermost sheet on the loading surface 49a constant. For this purpose, in the present embodiment, the tray lifting motor MT18 as a lowering part lowers the first tray 49 or the second tray 71 according to the loading of the sheets so that the height of the uppermost sheet of the sheets discharged by the discharge roller pair 42 or the second discharge roller pair 207 and stacked on the first tray 49 or the second tray 71 falls within a predetermined range, and when the sheets stacked on the first tray 49 or the second tray 71 are removed, the first tray 49 or the second tray 71 is lifted.

[0058] Also, above the first tray 49, a pair of alignment plates 401, 402 for aligning the width direction of the sheets intersecting the discharge direction of the sheets and a paddle 275 for aligning the discharge direction of the sheets are arranged. The pair of alignment plates 401, 402 are movable in the vertical direction and also movable in the width direction. That is, the pair of alignment plates 401, 402 can be lifted and lowered by a jogger lifting motor MT19 as an alignment member lifting part between a first position where the uppermost sheet on the first tray 49 can be aligned and a second position above the first position and not interfering with the sheets discharged from the discharge roller pair 42. Also, at least one of the pair of alignment plates 401, 402 is movable between an alignment position for aligning the width direction of the sheet bundle and a position away from the width direction edge of the sheet bundle compared to the alignment position. Specifically, the pair of alignment plates 401, 402 can be moved by a jogger 1 movement motor MT20 and a jogger 2 movement motor MT21 as alignment member movement parts between an alignment position for aligning the width direction of the uppermost sheet and a position away from the uppermost sheet in the width direction compared to the alignment position. Note that the position away from the uppermost sheet in the width direction compared to the alignment position is, for example, the sheet receiving position described later.

[0059] On the loading surface 49a of the first tray 49, a recess 49b is formed into which the pair of alignment plates 401 and 402 can intrude when they descend. FIGS. 6 and 7 show a state where the pair of alignment plates 401 and 402 are in a second position retracted above the nip point N1 of the upper conveyance roller 41 and the lower conveyance roller 48, and in this state, the sheet is discharged from the opening 31a. Then, when the sheet is discharged onto the first tray 49, the pair of alignment plates 401 and 402 descend to a first position where a part of them intrudes into the recess 49b, and by moving in the width direction from the sheet receiving position to the alignment position, the both ends in the width direction of the sheet are struck from both sides in the width direction of the sheet. Thereby, the width direction alignment of the sheet is performed.

[0060] On the other hand, the paddle 275 is movable in the vertical direction and can convey the sheet on the first tray 49 in a direction opposite to the discharge direction by rotating. That is, the paddle 275 can move to a conveyance position where it contacts the sheet on the first tray 49 and conveys the sheet upstream with respect to the sheet discharge direction, and to an upper position retracted above the conveyance position. FIGS. 6 and 7 show a state where the paddle 275 is retracted above the opening 31a (a state of being in the upper position), and in this state, the sheet is discharged from the opening 31a. Then, when the sheet is discharged onto the first tray 49, the paddle 275 descends toward the conveyance position, and by rotating the paddle 275, the sheet discharged from the opening 31a is conveyed toward the abutting member 271 while being dropped onto the first tray 49.

[0061] [Alignment plate] Next, with reference to FIGS. 8 and 9, the configuration of the pair of alignment plates 401 and 402 will be described. The pair of alignment plates 401 and 402 are each supported via a pair of swing arms 403 and 404 so as to be swingable in the vertical direction with respect to a swing shaft 405. The pair of swing arms 403 and 404 and the swing shaft 405 will be described later.

[0062] FIG. 8 is a perspective view of the periphery of a pair of alignment plates 401 and 402 in a home position (second position), and FIG. 9 is a perspective view of the periphery of a pair of alignment plates 401 and 402 in a state where the pair of alignment plates 401 and 402 has descended from the second position to the first position. The state in FIG. 9 is a state where the pair of alignment plates 401 and 402 is simply lowered from the second position to the first position, but the postures of the pair of alignment plates 401 and 402, that is, the angles of the second virtual line α2 (FIG. 19(a)) described later with respect to the horizontal direction, are the same as the postures in the alignment position.

[0063] The pair of alignment plates 401 and 402 each have an alignment surface 4001 as an alignment portion, a guide surface 4002 as an acceptance portion (guide portion), and a sheet receiving surface 4003 as an inclined portion (upstream guide portion). Note that the configurations of the alignment plates 401 and 402 are only arranged such that the alignment surfaces 4001 for aligning the sheets face each other, and since the basic configurations are the same, hereinafter, the alignment plate 401 will be representatively labeled and described.

[0064] The alignment surface 4001 is a surface that contacts both end edges in the width direction of the sheet bundle when aligning the sheet bundle, and it may be a flat surface or a surface with some irregularities. The alignment plates 401 and 402 each have a first portion 4001a on the downstream side and a second portion 4001b on the upstream side with respect to the sheet discharge direction by the discharge roller pair 42. The width of the first portion 4001a in the vertical direction (the length in the vertical direction) is larger than the width of the second portion 4001b in the vertical direction. Also, the upper end portions of the first portion 4001a and the second portion 4001b are located in a straight line and are continuous with the guide surface 4002 described later.

[0065] On one hand, the lower end of the first part 4001a is inclined such that a part on the downstream side with respect to the discharge direction slopes upward more as it goes downstream, and the upstream side of this part slopes upward more as it goes upstream. And the lower end of the second part 4001b is continuous with the lower end of the upstream side part of the first part 4001a, and further slopes upward more as it goes upstream in the discharge direction at an inclination angle larger than that of this upstream side part. Thereby, the vertical width of the first part 4001a of the alignment surface 4001 is made larger than the width of the second part 4001b. And the first part 4001a of the alignment surface 4001 can be brought into contact with, or opposed to, the widthwise edge of the sheet on the first tray 49 in a wide range in the vertical direction. Incidentally, the recess 49b of the first tray 49 described above has a shape corresponding to the shape of the lower end portions of the alignment plates 401 and 402 so that the lower end portions can penetrate therein.

[0066] The guide surface 4002 allows for the temporary acceptance of the next sheet above the first tray 49 when the pair of alignment plates 401 and 402 are aligning the sheet stack. Here, "when aligning the sheet stack" refers to a series of operations in which the pair of alignment plates 401 and 402 move from the receiving position to the alignment position and then return to the receiving position. Also, "temporary acceptance of the next sheet" means guiding the next sheet in the same job as the sheet stack being aligned on the first tray 49 or the next sheet in the job consecutive to the job of this sheet stack temporarily above the first tray 49 until the alignment of the sheet stack is completed. When the "next sheet" is the next sheet in the same job as the sheet stack being aligned on the first tray 49, for example, in a job where 10 sheets form one sheet stack, the "next sheet" refers to the second to tenth sheets. Also, when the "next sheet" is the next sheet in the job consecutive to the job of the sheet stack being aligned on the first tray 49, for example, when two jobs where 10 sheets form one sheet stack are consecutive, the "next sheet" refers to the first sheet of the second sheet stack (the eleventh sheet counted from the job of the first sheet stack). Then, the pair of alignment plates 401 and 402 align the next sheet temporarily accepted by the guide surface 4002 together with the sheet stack aligned when this next sheet was temporarily accepted.

[0067] Specifically, the guide surface 4002 is a surface that guides the next sheet above the alignment surface 4001 that aligns the top sheet when the pair of alignment plates 401 and 402 are aligning the top sheet at the alignment position and the next sheet is discharged from the discharge roller pair 42 in a state where it is displaced in the width direction with respect to the top sheet. The guide surface 4002 is formed on the upper surfaces of the pair of alignment plates 401 and 402 respectively. As described above, the loading surface 49a of the first tray 49 is inclined at a first angle with respect to the horizontal direction so as to go upward as it goes downstream in the discharge direction. On the other hand, the guide surface 4002 is inclined at a second angle greater than the first angle with respect to the horizontal direction so as to go upward as it goes downstream in the discharge direction at the alignment position.

[0068] Further, as shown in FIG. 19(a) described later, which shows the state where the alignment plates 401 and 402 are in the alignment position, the upstream end portion of the guide surface 4002 in the discharge direction is below the nip line N2 which is a line extending the nip surface of the upper conveyance roller 41 and the lower conveyance roller 48, which are a pair of conveyance rollers, downstream in the discharge direction in the state where the pair of alignment plates 401 and 402 are in the alignment position. The nip line N2 is in the same direction as the discharge direction of the sheet by the discharge roller pair 42. Therefore, the downstream end (front end) of the sheet discharged from the discharge roller pair 42 can more easily pass above the upstream end portion of the guide surface 4002. When the angle of the nip line N2 with respect to the horizontal direction is large, the upstream end portion of the guide surface 4002 may be positioned above the nip point N1. However, in order to make it difficult for the front end of the discharged sheet to be caught by the upstream end portion of the guide surface 4002, it is preferable that the upstream end portion of the guide surface 4002 is positioned below the nip point N1 with respect to the vertical direction.

[0069] As described above, in the present embodiment, the angle of the guide surface 4002 with respect to the horizontal direction is made larger than the angle of the stacking surface 49a with respect to the horizontal direction. For this reason, it is possible to secure the vertical width of the first portion 4001a of the alignment surface 4001, and it is possible to easily position the upstream end portion of the guide surface 4002 below the nip line N2, more preferably below the nip point N1. As a result, it is possible to align the sheet over a wide range of the alignment surface 4001, and it is possible to make it difficult for the discharged sheet to be caught by the upstream end portion of the guide surface 4002. If the sheet can be aligned over a wide range of the alignment surface 4001, the sheet loading amount of the first tray 49 that can be aligned by the alignment plates 401 and 402 can be increased.

[0070] The sheet receiving surface 4003 as the inclined portion is provided at the upstream end of the guide surface 4002 in the discharge direction in a state where the pair of alignment plates 401 and 402 are in the aligned position, and is inclined so as to face inward on the side where the topmost sheet is located in the width direction as it goes toward the downstream side in the discharge direction, and is a surface for guiding the next sheet discharged from the discharge roller pair 42 to the guide surface 4002. That is, the sheet receiving surface 4003 has a role of receiving the leading end of the sheet discharged from the discharge roller pair 42 onto the guide surface 4002 so as to scoop it up in a state where the pair of alignment plates 401 and 402 are in the aligned position.

[0071] Such a sheet receiving surface 4003 is inclined downward as it goes inward in the width direction in a state where the pair of alignment plates 401 and 402 are in the aligned position. Thereby, for example, even if a sheet with weak stiffness is discharged so as to hang down from the discharge roller pair 42, it is easy to scoop up the leading end of this sheet by the sheet receiving surface 4003. In addition, for example, if the position of the upstream end of the guide surface 4002 is close to the discharge roller pair 42 and the position of the upstream end of the guide surface 4002 is sufficiently lower than the nip point N1, and the sheet discharged from the discharge roller pair 42 easily passes over the guide surface 4002, the sheet receiving surface 4003 may be omitted.

[0072] In this embodiment, since the guide surfaces 4002 are provided on the pair of alignment plates 401 and 402 as described above, even if the next sheet is discharged while the pair of alignment plates 401 and 402 are aligning the sheet as will be described later, the next sheet can be guided by the guide surface 4002. If there is no such guide surface 4002, when the next sheet is discharged with the alignment plates 401 and 402 in the alignment position, the next sheet may collide with one of the alignment plates, disturbing the posture of the sheet or causing the sheet to bend. In particular, as will be described later, when the interval between the continuously discharged sheets is narrowed in order to increase productivity, the sheet will be discharged with the alignment plates 401 and 402 in the alignment position. In this embodiment, since there is the guide surface 4002 for guiding the sheet discharged from the discharge roller pair 42 with the alignment plates 401 and 402 in the alignment position as described above, it is possible to reduce the collision of the sheet with one of the alignment plates. The operation of the alignment plates 401 and 402 during sheet discharge will be described later.

[0073] [Drive Configuration of Alignment Plates and Paddles] Next, with reference to FIGS. 8 to 11, the drive configuration of the pair of alignment plates 401 and 402 and the paddle 275 will be described. FIGS. 8 and 10 are perspective views of the periphery of the pair of alignment plates 401 and 402 with the pair of alignment plates 401 and 402 in the home position, and FIGS. 9 and 11 are perspective views of the periphery of the pair of alignment plates 401 and 402 with the pair of alignment plates 401 and 402 lowered from the home position to the first position. Also, in FIGS. 8 and 9, the jogger lift HP detection sensor SN6 and the paddle lift HP detection sensor SN9 are omitted for the sake of explanation, whereas in FIGS. 10 and 11, the jogger lift HP detection sensor SN6 and the paddle lift HP detection sensor SN9 are also shown.

[0074] The alignment plate 401 on the front side (the upper right side in FIGS. 8 to 11) moves in the width direction by the front side movement mechanism 410, and the alignment plate 402 on the rear side (the lower left side in FIGS. 8 to 11) moves in the width direction by the rear side movement mechanism 420. Further, the pair of alignment plates 401 and 402 move in the vertical direction by the alignment plate lifting mechanism 430, and the paddle 275 moves in the vertical direction by the paddle lifting mechanism 440. Such a pair of alignment plates 401 and 402 are supported via a pair of swing arms 403 and 404, and the paddle 275 is supported via a paddle arm 276 so as to be swingable in the vertical direction with respect to the swing shaft 405.

[0075] The swing shaft 405 is arranged across the width direction above the pair of discharge rollers 42. The position of the swing shaft 405 with respect to the discharge direction is as close as possible to the pair of discharge rollers 42. In the present embodiment, it is located further upstream than the upstream end in the discharge direction of the recess 49b of the first tray 49. The pair of swing arms 403 and 404 are driven by a jogger lifting motor MT19 as an alignment member lifting part, and can swing in the vertical direction around the swing shaft 405 arranged above the pair of discharge rollers 42. Specifically, when the drive of the jogger lifting motor MT19 is transmitted to the pair of swing arms 403 and 407 via the alignment plate lifting mechanism 430, the pair of swing arms 403 and 407 swing in the vertical direction around the swing shaft 405. The pair of alignment plates 401 and 402 are arranged inside the pair of swing arms 403 and 404 on the side where the uppermost sheet is located with respect to the width direction, and are rotatably connected to the pair of swing arms 403 and 404.

[0076] The pair of swing arms 403 and 404 are supported so as to be rotatable with respect to the swing shaft 405 and movable relative to each other along the axial direction. Therefore, the swing arms 403 and 404 do not swing only by the rotation of the swing shaft 405. For this reason, the sheet loading device 400 has an alignment plate lifting mechanism 430 as a drive transmission part. The alignment plate lifting mechanism 430 transmits the drive of the jogger lifting motor MT19 to swing the swing arms 403 and 404 around the swing shaft 405, and has a transmission mechanism 431, a parallel shaft 432, a connecting part 433, and an engagement hole 434 as an engagement part.

[0077] The transmission mechanism 431 includes a gear 431a to which drive is transmitted from the drive gear of the jogging lifting motor MT19, a pulley (not shown) that rotates integrally with the gear 431a, a pulley 431b fixed to the swing shaft 405, and a belt 431c that is stretched between the pulley on the gear 431a side and the pulley 431b. The driving force of the jogging lifting motor MT19 is transmitted to the swing shaft 405 via the gear 431a, the pulley (not shown), the belt 431c, and the pulley 432b.

[0078] The parallel shafts 432 are provided parallel to the swing shaft 405 and are connected to the swing shaft 405 by the connecting portions 433. In the present embodiment, the parallel shafts 432 are respectively arranged on the front side and the rear side of the paddle 275, and each parallel shaft 432 is connected to the swing shaft 405 by the connecting portion 433. Therefore, the pair of parallel shafts 432 rotate about the swing shaft 405 as the swing shaft 405 rotates. The engagement holes 434 are respectively provided in the pair of swing arms 403 and 404, and when the parallel shaft 432 engages with the parallel shaft 432 and rotates about the swing shaft 405, the pair of swing arms 403 and 404 are rotated together with the parallel shaft 432. Thereby, the pair of alignment plates 401 and 402 respectively supported by the pair of swing arms 403 and 404 move in the vertical direction.

[0079] Such an engagement hole 434 is a through hole through which the parallel shaft 432 can be inserted and in which the parallel shaft 432 and the swing arms 403 and 404 can relatively move within a predetermined range with respect to the rotational direction about the swing shaft 405. That is, the engagement hole 434 is a through hole having a shape curved in a direction along an arc centered on the swing shaft 405, and the inserted parallel shaft 432 can relatively move within a predetermined range in the direction along this arc. The parallel shaft 432 inserted into the engagement hole 434 engages with the upstream end portion in the discharge direction of the engagement hole 434 at the home position (second position) in FIG. 8 due to the self-weight of the swing arms 403 and 404. Also, at the first position shown in FIG. 9, the parallel shaft 432 inserted into the engagement hole 434 engages with the upstream end portion in the discharge direction of the engagement hole 434 due to the self-weight of the swing arms 403 and 404.

[0080] However, for example, when descending from the second position to the first position, if the pair of alignment plates 401 and 402 contact the sheet or the stack of sheets on the first tray 49 before reaching the first position, the pair of alignment plates 401 and 402 and the pair of swing arms 403 and 404 will be in a lifted state rather than the state when they are in the first position. At this time, if the parallel shaft 432 and the pair of swing arms 403 and 404 are connected so as not to be relatively movable in the rotational direction, the jogger lifting and lowering motor MT19 will be driven by the amount of movement until the pair of alignment plates 401 and 402 reach the first position, and the sheet on the first tray 49 may be damaged by the pair of alignment plates 401 and 402. On the contrary, as described above, by making the parallel shaft 432 and the engagement hole 434 relatively movable within a predetermined range in the rotational direction, even if the pair of alignment plates 401 and 402 contact the sheet, the parallel shaft 432 moves within the engagement hole 434, and the amount of movement of the pair of alignment plates 401 and 402 as described above can be absorbed. As a result, it is possible to suppress damage to the sheet on the first tray 49.

[0081] The paddle 275 is rotatably supported at the tip of the paddle arm 276. The paddle arm 276 is rotatably supported with respect to the swing shaft 405. Therefore, the paddle arm 276 does not swing only by the rotation of the swing shaft 405. For this reason, the sheet loading device 400 has a paddle lifting mechanism 440. The paddle lifting mechanism 440 transmits the drive of the paddle lifting and lowering motor MT22 to swing the paddle arm 276 around the swing shaft 405. The drive is transmitted from the drive gear 441 of the paddle lifting and lowering motor MT22 to the gear 442, the pulley 443 that rotates integrally with the gear 442, the pulley 444 that is rotatably supported by the swing shaft 405 and fixed to the paddle arm 276, and the belt 445 that is wound around the pulley 443 and the pulley 444. The driving force of the paddle lifting and lowering motor MT22 is transmitted to the paddle arm 276 via the drive gear 441, the gear 442, the pulley 443, the belt 445, and the pulley 444. When the paddle arm 276 swings around the swing shaft 405, the paddle 275 supported at the tip of the paddle arm 276 moves vertically between the above-described conveying position and the upper position.

[0082] This paddle 275 is rotationally driven by a discharge roller 1 motor MT6 (not shown in FIGS. 8 to 11) via a paddle drive mechanism 450. That is, in the present embodiment, the drive sources of the upper conveyance roller 41 and the paddle 275 are common. For this reason, while the upper conveyance roller 41 is rotationally driven, the paddle 275 is also rotating. Note that the rotational drive of the paddle 275 may be performed by a single motor. The paddle drive mechanism 450 transmits the drive of the discharge roller 1 motor MT6 to rotate the paddle 275, and includes a first transmission part 451 to which the drive is transmitted from the drive shaft of the discharge roller 1 motor MT6, a transmission shaft 452 to which the drive is transmitted from the first transmission part 451, a second transmission part 453 to which the drive is transmitted from the transmission shaft 452, and a third transmission part 454 that transmits the drive transmitted to the second transmission part 453 to the paddle 275.

[0083] The first transmission part 451, the second transmission part 453, and the third transmission part 454 are each composed of various power transmission members such as gears, pulleys, and belts. The first transmission part 451 is arranged on the rear side of the swing shaft 405 in the width direction, and the second transmission part 453 and the third transmission part 454 are arranged between a pair of alignment plates 401 and 402 in the width direction. The transmission shaft 452 is arranged above the swing shaft 405 and parallel to the swing shaft 405, and connects the first transmission part 451 and the second transmission part 453 so as to be able to transmit drive. An output pulley 453a that outputs the drive input to the second transmission part 453 and an input pulley 454a to which the drive is input to the third transmission part 454 are integrated, and a belt 454c is stretched between the input pulley 454a of the third transmission part 454 and a pulley 454b fixed to the rotation shaft of the paddle 275. The output pulley 453a and the input pulley 454a are supported so as to be relatively rotatable with respect to the swing shaft 405. With this configuration, the driving force of the discharge roller 1 motor MT6 input to the first transmission part 451 from the rear side is transmitted to the paddle 275 via the transmission shaft 452, the second transmission part 453, and the third transmission part 454, and the paddle 275 rotates.

[0084] As described above, the front alignment plate 401 moves in the width direction by the front side movement mechanism 410, and the rear alignment plate 402 moves in the width direction by the rear side movement mechanism 420. Further, the pair of alignment plates 401 and 402 are supported so as to be movable in the width direction with respect to the swing axis 405 via the pair of swing arms 403 and 404. The configurations of the front side movement mechanism 410 and the rear side movement mechanism 420 are the same. The front side movement mechanism 410 includes a gear 412 to which the drive of the drive gear 411 of the jogger 1 movement motor MT20 is transmitted, a pulley 413 that rotates integrally with the gear 412, a pair of pulleys 414 disposed outside the movement range in the width direction of the alignment plate 401 with respect to the direction parallel to the swing axis 405, a belt 415 wound around the pulley 413 and the pair of pulleys 414, and a tension pulley 416 that applies tension to the belt 415. Among the belt 415, the portion wound around the pair of pulleys 414 is parallel to the swing axis 405, and a slide member 435 is fixed to a part of the portion of the belt 415 parallel to the swing axis 405. The slide member 435 is movable in the width direction together with the swing arm 403, but is connected to the swing arm 403 so as to be relatively rotatable so as not to rotate even when the swing arm 403 rotates about the swing axis 405. For this reason, the portion of the belt 415 parallel to the swing axis 405 moves parallel to the swing axis 405 by the rotational drive of the jogger 1 movement motor MT20, and the swing arm 403 fixed to this portion moves in the width direction along the swing axis 405. Since the alignment plate 401 is supported by the swing arm 403, the alignment plate 401 moves in the width direction together with the swing arm 403.

[0085] Similarly, the rear movement mechanism 420 includes a gear 422 to which the drive of the drive gear 421 of the jogger 2 movement motor MT21 is transmitted, a pulley 423 that rotates integrally with the gear 422, a pair of pulleys 424 disposed outside the movement range in the width direction of the alignment plate 402 with respect to the direction parallel to the swing shaft 405, a belt 425 wound around the pulley 423 and the pair of pulleys 424, and a tension pulley 426 that applies tension to the belt 425. Among the belt 425, the portion wound around the pair of pulleys 424 is parallel to the swing shaft 405, and a slide member 435 is fixed to a part of the portion of the belt 425 parallel to the swing shaft 405. The slide member 435 is movable in the width direction together with the swing arm 404, but is connected to the swing arm 404 so as to be relatively rotatable so that it does not rotate even when the swing arm 404 rotates about the swing shaft 405. Therefore, due to the rotational drive of the jogger 2 movement motor MT21, the portion of the belt 425 parallel to the swing shaft 405 moves parallel to the swing shaft 405, and the swing arm 404 fixed to this portion moves in the width direction along the swing shaft 405. Since the alignment plate 402 is supported by the swing arm 404, the alignment plate 402 moves in the width direction together with the swing arm 404.

[0086] With such a configuration, the pair of alignment plates 401 and 402 can move independently in the width direction by the drive of the jogger 1 movement motor MT20 and the jogger 2 movement motor MT21, respectively. Note that the pair of alignment plates 401 and 402 may be moved in the width direction synchronously by one motor. Also, the parallel shafts 432 for moving the pair of alignment plates 401 and 402 in the vertical direction are arranged parallel to the swing shaft 405, and the engagement holes 434 provided in the swing arms 403 and 404 are through holes through which the parallel shafts 432 are inserted. Therefore, when the pair of alignment plates 401 and 402 move, the engagement holes 434 engage with the parallel shafts 432 while allowing the pair of alignment plates 401 and 402 to move in the width direction. Also, since the engagement holes 434 and the parallel shafts 432 are engaged regardless of the positions of the pair of alignment plates 401 and 402 in the width direction, the pair of alignment plates 401 and 402 can move in the vertical direction at any position in the width direction.

[0087] [Regarding the sensors around the integration board] Next, using FIGS. 10 and 11, the jogger lift HP detection sensor SN6, jogger 1HP detection sensor SN7, jogger 2HP detection sensor SN8, and paddle lift HP detection sensor SN9 for detecting the positions of the integration boards 401 and 402 in the width direction and lift direction, and the lift direction position of the paddle 275 will be described. Each of these sensors is a photo interrupter having a light emitting part and a light receiving part that faces the light emitting part and receives the light emitted from the light emitting part. When a flag enters between the light emitting part and the light receiving part and blocks the light from the light emitting part, it turns ON.

[0088] First, a flag 406 is fixed to the swing shaft 405 or the pulley 431b. Also, a jogger lift HP detection sensor SN6 is provided at the position where the flag 406 passes. When the jogger lift motor MT19 is rotationally driven to raise and lower the pair of integration boards 401 and 402, this driving force is transmitted to the swing shaft 405 via the integration board lift mechanism 430, and the flag 406 also rotates together with the swing shaft 405. FIG. 10 shows a state where the pair of integration boards 401 and 402 are in the home position, that is, the second position in the lift direction. In this state, the flag 406 does not enter the jogger lift HP detection sensor SN6, and the sensor is in the OFF state. The stacker control unit 330 determines in this state that the pair of integration boards 401 and 402 are in the home position in the lift direction.

[0089] Then, when the pair of integration boards 401 and 402 start to descend from the second position, the flag 406 enters the jogger lift HP detection sensor SN6, and the sensor becomes ON. Further, even when the pair of integration boards 401 and 402 descend and reach the first position shown in FIG. 11, the flag 406 remains in the state of entering the jogger lift HP detection sensor SN6. The stacker control unit 330 determines that the pair of integration boards 401 and 402 are in the first position, for example, by driving the jogger lift motor MT19 for a predetermined number of pulses or a predetermined time after the flag 406 enters the jogger lift HP detection sensor SN6.

[0090] Next, among the belts 415 for moving the front alignment plate 401 in the width direction, a flag 417 is fixed to a slide member 435 fixed to a portion wound around a pair of pulleys 414, and a flag 427 is fixed to a slide member 435 fixed to a portion wound around a pair of pulleys 424 among the belts 425 for moving the rear alignment plate 402 in the width direction. Also, at positions where the flags 417 and 427 pass, a jogger 1 HP detection sensor SN7 and a jogger 2 HP detection sensor SN8 are provided respectively. When the jogger 1 moving motor MT20 is rotationally driven to move the front alignment plate 401 in the width direction, this driving force is transmitted to the swing arm 403 via the front side moving mechanism 410. At this time, since a portion of the belt 415 of the front side moving mechanism 410 wound around a pair of pulleys 414 moves in the width direction, the flag 417 fixed to this portion moves in the width direction together with the front side swing arm 403 and the alignment plate 401. Similarly, the rear flag 427 moves in the width direction together with the rear swing arm 404 and the alignment plate 402.

[0091] FIG. 10 shows a state where the pair of alignment plates 401 and 402 are in the home position also in the width direction. In this state, the flags 417 and 427 have entered the jogger 1 HP detection sensor SN7 and the jogger 2 HP detection sensor SN8 respectively, and the sensors are in the ON state. The stacker control unit 330 determines in this state that the pair of alignment plates 401 and 402 are in the home position in the width direction. Then, when the pair of alignment plates 401 and 402 move outward in the width direction from the home position, the flags 417 and 427 come out of the jogger 1 HP detection sensor SN7 and the jogger 2 HP detection sensor SN8 respectively, and the sensors become OFF. The stacker control unit 330 controls the positions of the pair of alignment plates 401 and 402 in the width direction, for example, by counting the number of pulses of the jogger 1 moving motor MT20 and the jogger 2 moving motor MT21 when the jogger 1 HP detection sensor SN7 and the jogger 2 HP detection sensor SN8 are in the OFF state.

[0092] Next, a flag 277 is provided at a portion rotatably supported on the swing axis 405 of the paddle arm 276. Further, a paddle lift HP detection sensor SN9 is provided at a position where the flag 277 passes. When the paddle lift motor MT22 is rotationally driven to raise and lower the paddle 275, this driving force is transmitted to the paddle arm 276 via the paddle lift mechanism 440, and the flag 277 swings about the swing axis 405 together with the paddle arm 276. FIG. 10 shows a state where the paddle 275 is in the home position, that is, the upper position. In this state, the flag 277 enters the paddle lift HP detection sensor SN9, and the sensor is in the ON state. The stacker control unit 330 determines in this state that the paddle 275 is in the home position.

[0093] Then, when the paddle 275 starts to descend from the upper position, the flag 277 comes out of the paddle lift HP detection sensor SN9, and the sensor becomes the OFF state. Further, with the sensor remaining in the OFF state, the paddle 275 descends and reaches the conveyance position shown in FIG. 11. The stacker control unit 330 determines that the paddle 275 is located at the conveyance position, for example, by driving the paddle lift motor MT22 for a predetermined number of pulses or a predetermined time after the flag 277 comes out of the paddle lift HP detection sensor SN9.

[0094] [Interlocking mechanism] Next, the interlocking mechanism 460 that changes the angles of the pair of alignment plates 401 and 402 in conjunction with the swinging of the pair of swing arms 403 and 404 will be described with reference to FIGS. 12 and 13. The pair of alignment plates 401 and 402 are rotatably connected to the pair of swing arms 403 and 404 about a rotation axis 465, and extend upstream in the discharge direction from the rotation axis 465. In the present embodiment, the interlocking mechanism 460 rotates the pair of alignment plates 401 and 402 with respect to the rotation axis 465 in conjunction with the swinging of the pair of swing arms 403 and 404 so that the angles of the alignment plates 401 and 402 with respect to the horizontal direction in the extending direction are substantially constant regardless of the positions in the swinging directions of the pair of swing arms 403 and 404.

[0095] Figs. 19(a) and (b) described below show a state in which a pair of alignment plates 401 and 402 are in the first position in the vertical direction and in the alignment position in the width direction. Here, as shown in Fig. 19(a), a line connecting the center P1 of the swing axis 405 and the center P2 of the rotation axis 465 is defined as the first virtual line α1, and a line connecting the center P2 of the rotation axis 465 and the upstream end in the discharge direction of the pair of alignment plates 401 and 402 and the position P3 of the upper ends of the pair of alignment plates 401 and 402 in the alignment position is defined as the second virtual line α2. In this case, in the present embodiment, the angle θ formed by the first virtual line α1 and the second virtual line α2 is made smaller at the second position than at the first position. Note that the first position is a position where the pair of alignment plates 401 and 402 can align the uppermost sheet in the vertical direction, and the second position is above the first position in the vertical direction and does not interfere with the sheet discharged from the discharge roller pair 42. The second position is the same as the home position shown in Fig. 6 in the vertical direction. Also, as shown in Fig. 19(a), in the present embodiment, the angle θ formed by the first virtual line α1 and the second virtual line α2 is an acute angle at the first position.

[0096] As described above, the swing arms 403 and 404 swing vertically about the swing axis 405 via the alignment plate lifting mechanism 430 by the jogger lifting motor MT19. The interlocking mechanism 460 changes the angle θ formed by the first virtual line α1 and the second virtual line α2 in conjunction with the swinging motion of the swing arms 403 and 404 about the swing axis 405. The interlocking mechanism 460 will be described in detail. Note that the interlocking mechanism 460 is disposed inside the swing arms 403 and 404, respectively, and rotates the alignment plates 401 and 402 with respect to the tip portions of the swing arms 403 and 404 in conjunction with the swinging motion of the swing arms 403 and 404. Since the configurations of the interlocking mechanism 460 for rotating the alignment plates 401 and 402 are the same, Figs. 12 and 13 will representatively describe the interlocking mechanism 460 for rotating the alignment plate 402 in conjunction with the swinging motion of the swing arm 404.

[0097] The linkage mechanism 460 includes a toothed pulley 461 as a first toothed pulley, a toothed pulley 462 as a second toothed pulley, and a toothed belt 463. The toothed pulley 461 is rotatably supported with respect to the swing shaft 405, and the phase in the rotational direction about the swing shaft 405 does not change regardless of the swinging operation of the swing arm 404. In the present embodiment, the toothed pulley 461 is fixed to the slide member 435. The toothed pulley 462 is fixed to the alignment plate 402 and is rotatable together with the alignment plate 402 about the rotation shaft 465. The toothed belt 463 is stretched between the toothed pulley 461 and the toothed pulley 462. The toothed pulleys 461 and 462 each have a plurality of teeth formed on their outer peripheral surfaces. The toothed belt 463 has a plurality of teeth formed on its inner peripheral surface that mesh with the plurality of teeth formed on the toothed pulleys 461 and 462, respectively.

[0098] Also, in the present embodiment, it has a spring 464 as a tension applying portion for applying tension to the toothed belt 463. The spring 464 connects the first portion 463a and the second portion 463b of the toothed belt 463 in a state where the portion between the first portion 463a and the second portion 463b is bent. That is, in a state where the toothed belt 463 between the first portion 463a and the second portion 463b is bent, one end portion of the spring 464 is fixed to the first portion 463a by the fixing portion 464a, and the other end portion of the spring 464 is fixed to the second portion 463b by the fixing portion 464b. Thereby, the pulling force of the spring 464 acts between the first portion 463a and the second portion 463b, and tension can be applied to the toothed belt 463.

[0099] Here, when no tension is applied to the toothed belt 463, there is a risk that the toothed belt 463 may be over-tightened or loosened due to the tolerances of the toothed pulleys 461, 462 and the toothed belt 463. If the toothed belt 463 is over-tightened, it will become a load for the oscillation of the oscillation arm 404. On the other hand, if the toothed belt 463 is loose, the appropriate positioning of the rotation position around the rotation shaft 465 of the alignment plate 402 cannot be achieved. In other words, the alignment plate 402 cannot be set in an appropriate posture. In particular, the posture of the alignment plate 402 is determined in a state where the lower portion of the toothed belt 463 stretched by the toothed pulleys 461, 462 is stretched. Therefore, when the lower portion of the toothed belt 463 bends, the upstream end of the alignment plate 402 will be in a posture where it has dropped relative to the desired posture. In order to apply tension to the toothed belt 463, for example, a tensioner that biases a part of the toothed belt 463 outward or inward may be provided, but in this case, the device will become larger. For this reason, in the present embodiment, as described above, by bending a part of the toothed belt 463 and providing the spring 464, tension is applied to the toothed belt 463.

[0100] FIG. 12 shows a state where the alignment plate 402 is located at the home position (second position). When the jogging lift motor MT19 is driven to lower the alignment plate 402 from this state, the oscillation arm 404 oscillates downward via the alignment plate lifting mechanism 430. At this time, the toothed pulley 461 fixed to the slide member 435 does not rotate, and the phase in the rotation direction is maintained. On the other hand, the toothed pulley 462 rotatably supported by the rotation shaft 465 provided at the tip of the oscillation arm 404 rotates via the toothed belt 463 spanned between the toothed pulley 461 and the toothed pulley 462 as the tip of the oscillation arm 404 drops and the vertical position relative to the toothed pulley 461 changes.

[0101] As described above, since the toothed pulley 462 is fixed to the alignment plate 402, the alignment plate 402 also rotates about the rotation axis 465 together with the toothed pulley 462 due to the downward swing of the swing arm 404. That is, the positions where the plurality of teeth on the inner peripheral surface of the toothed belt 463 mesh with the plurality of teeth on the outer peripheral surface of the toothed pulley 461 change, and the toothed belt 463 rotates in the direction of arrow 463c in FIG. 12. As a result, the toothed pulley 462 rotates clockwise (in the direction of arrow 465a) when viewed in the direction of the rotation axis of the rotation axis 465 from the lower left to the upper right in FIG. 12. As a result, the alignment plate 402 descends to the first position shown in FIG. 13 while generally maintaining its posture, that is, the angle of the second virtual line α2 with respect to the horizontal direction. When raising the alignment plate 402 from the first position to the second position, the toothed belt 463 and the toothed pulley 462 rotate in the opposite direction to the above, thereby generally maintaining the posture of the alignment plate 402.

[0102] Note that although the number of teeth of the toothed pulleys 461 and 462 is the same, they may be different. Thereby, the ratio of the angle (the angle θ formed by the first virtual line α1 and the second virtual line α2) between the alignment plate 402 and the swing arm 404 with respect to the swing amount of the swing arm 404 can be changed. For example, when the number of teeth of the toothed pulley 462 is reduced with respect to the number of teeth of the toothed pulley 461, the amount of change in the angle θ with respect to the swing amount of the swing arm 404 increases, and when the number of teeth of the toothed pulley 462 is increased with respect to the number of teeth of the toothed pulley 461, the amount of change in the angle θ with respect to the swing amount of the swing arm 404 decreases.

[0103] In this embodiment, the alignment plate 402 is movable between the first position and the second position while generally maintaining the posture of the alignment plate 402 by the interlocking mechanism 460 in this way. Therefore, although it will be described in detail later, the angle θ formed by the first virtual line α1 and the second virtual line α2 is smaller at the second position shown in FIGS. 8, 10, and 12 than at the first position shown in FIGS. 9, 11, and 13. That is, in this embodiment, the pair of alignment plates 401 and 402 are movable between the first position and the second position while generally maintaining a posture extending upstream of the discharge direction from the rotation axis 465 with respect to the pair of swing arms 403 and 404.

[0104] For example, if a pair of alignment plates 401 and 402 are extended downstream of the discharge direction from the rotation axis 465, and the angles of the pair of alignment plates 401 and 402 with respect to the pair of swing arms 403 and 404 are the same at the first position and the second position, when the pair of alignment plates 401 and 402 are raised to the second position, the alignment plates 401 and 402 will protrude above the swing arms 403 and 404. In this case, in order to ensure the space for the alignment plates 401 and 402 at the second position, a large space is required above the first tray 49. Therefore, the second tray 71 above the first tray 49 cannot be lowered sufficiently, and the loading amount of the sheets on the second tray 71 will decrease.

[0105] In contrast, in this embodiment, the pair of alignment plates 401 and 402 are movable between the first position and the second position while generally maintaining the posture of extending upstream of the discharge direction from the rotation axis 465 with respect to the pair of swing arms 403 and 404. For this reason, even when the alignment plates 401 and 402 move to the second position, the alignment plates 401 and 402 do not protrude into the space above the swing arms 403 and 404, or even if they protrude, the amount of protrusion is small. Therefore, it becomes easier to ensure the amount of descent of the second tray 71 above the first tray 49, and the loading amount of the sheets on the second tray 71 can be ensured.

[0106] In the above example, the interlocking mechanism 460 is constituted by a toothed pulley and a toothed belt, but these may be constituted by a plurality of gears. That is, the interlocking mechanism 460 may be configured to rotate the alignment plates 401 and 402 about the rotation axis 465 in conjunction with the swinging operation of the swing arms 403 and 404 so that the postures of the alignment plates 401 and 402 are maintained even when the swing arms 403 and 404 swing in the vertical direction. When the interlocking mechanism is constituted by a pulley and a belt without teeth, it is difficult to move the alignment plates 401 and 402 vertically while maintaining their postures due to the slippage of the pulley and the belt. For this reason, the interlocking mechanism 460 is preferably constituted by a toothed pulley and a belt as in this embodiment, or by a plurality of gears that mesh with each other.

[0107] [Shift Discharge Mode] Here, in the case of this embodiment, the sheet stacking device 400 can execute a job of forming a sheet bundle at the same position in the sheet width direction on the first tray 49 by repeatedly aligning sheets one by one by a pair of alignment plates 401 and 402 a plurality of times. Such jobs include a shift discharge mode and a straight discharge mode described later. First, the shift discharge mode will be described, in which the sheets are moved (shifted) in the width direction and discharged onto the first tray 49 without being stapled, forming a sheet bundle composed of a plurality of unstapled sheets. In the shift discharge mode, for example, as shown in FIG. 30(b), a plurality of unstapled sheet bundles on the first tray 49 are shifted in the width direction with respect to each other and discharged. An example of such a shift discharge mode will be described with reference to FIGS. 14(a) to 22(b).

[0108] The stacker control unit 330 can execute the shift discharge mode. When the shift discharge mode is executed, the pair of alignment plates 401 and 402 operate as follows. First, a case will be described in which a job of shifting a first sheet bundle composed of a plurality of sheets stacked on the first tray 49 to one side in the width direction and stacking a second sheet bundle on the first tray 49 is executed. In this case, after the pair of alignment plates 401 and 402 align the first sheet bundle stacked on the first tray 49 at the first position, they rise from the first position to the second position. Next, after the leading end of the first sheet of the second sheet bundle following the first sheet bundle is discharged from the discharge roller pair 42, the pair of alignment plates 401 and 402 descend from the second position to the first position in a state shifted to one side from the position where the first sheet bundle was aligned, and align the sheets included in the second sheet bundle.

[0109] The discharging operation of the first sheet S11 of the first sheet bundle will be sequentially described below. Here, a case will be described in which the first sheet bundle is shifted to the front side and stacked on the first tray 49, and then the next second sheet bundle is shifted to the rear side and stacked on the first sheet bundle. As shown in FIGS. 14(a) and 14(b), the sheet S11 conveyed through the straight path 28 passes through the first conveying roller 201, and the position of the edge (side edge) in the width direction of the sheet S11 is detected by the registration detection sensor SN2. At this time, the pair of alignment plates 401 and 402 are positioned at the sheet receiving position in the shift discharging mode from the home position shown in FIGS. 6 and 7. That is, the pair of alignment plates 401 and 402 move from the second position to the first position in the vertical direction, and in the width direction, they are positioned 5 mm away from the width direction end (side edge) of the sheet at the position (reference position) where the sheet S11 is stacked on the first tray 49. In FIGS. 14(a) and 14(b), the alignment plates 401 and 402 are shifted to the front side with respect to the positions when the alignment plates discharge the sheet with the center in the width direction as a reference.

[0110] At this time, the pair of alignment plates 270 as shift members that perform sheet alignment and shifting on the processing tray 37 also shift to the front side with respect to the position with the center in the width direction as a reference. That is, the pair of alignment plates 270 are positioned at the first width direction position when the pair of alignment plates 401 and 402 are positioned at the first receiving position where the sheet is received at a predetermined position of the first tray 49. Further, the pair of alignment plates 270 are positioned at the second width direction position shifted to one side (here, the front side) in the width direction from the first width direction position when the pair of alignment plates 401 and 402 are positioned at the second receiving position where the sheet is received at a position shifted to one side (here, the front side) in the width direction from a predetermined position of the first tray 49.

[0111] Here, the pair of alignment plates 270 has a guide surface as a guide portion on the shift member side for guiding a sheet that is conveyed toward the discharge roller pair 42 without being placed on the processing tray 37. The guide surfaces 270a are respectively formed on the upper surfaces of the pair of alignment plates 270 on the downstream side in the conveyance direction from the pre-processing roller 36, and guide the sheet that has passed through the pre-processing roller 36 to the discharge roller pair 42. Also, in the states of FIGS. 14(a) and (b), the paddle 275 remains in the home position.

[0112] Note that the front side is the lower side in FIG. 14(b), the rear side is the upper side in FIG. 14(b), and FIG. 14(a) is a cross-sectional view seen from the front side. The same applies to FIGS. 15(a) to 22(b). Also, discharging the sheet based on the center in the width direction means, for example, discharging the sheet in a state where the center in the width direction of the straight path 28 substantially coincides with the center in the width direction of the sheet, and discharging the sheet without shifting the sheet by the second conveyance roller 202 and the third conveyance roller 203.

[0113] Next, as shown in FIGS. 15(a) and (b), the stacker control unit 330 shifts the sheet S11 to the front side by the second conveyance roller 202 and the third conveyance roller 203 based on the detection result of the registration detection sensor SN2. Then, the sheet S11 shifted to the front side is delivered to the pre-processing roller 36 and further conveyed from the pre-processing roller 36 toward the discharge roller pair 42. At this time, the lower surface of the sheet S11 heading toward the discharge roller pair 42 is supported by the guide surfaces 270a formed on the upper surfaces of the pair of alignment plates 270 on the processing tray 37 shifted to the front side as described above. Then, the sheet S11 is discharged from the discharge roller pair 42 while being supported by the guide surfaces 270a. In this way, since the sheet S11 is discharged while being supported by the guide surfaces 270a, the sheet S11 is discharged from the discharge roller pair 42 in a state where it is given firmness by the guide surfaces 270a.

[0114] Next, as shown in FIGS. 16(a) and 16(b), when the rear end (the upstream end in the conveyance direction) of the sheet S11 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveyance position, and the sheet S11 is conveyed upstream in the discharge direction while being dropped onto the first tray 49 by the paddle 275. That is, the paddle 275 scrapes in the sheet S11 and abuts the rear end of the sheet S11 against the abutting member 271. At this time, the second sheet S12 of the first sheet bundle has been conveyed to the pre-processing roller 36 in a state of being shifted to the front side, and the third sheet S13 has reached the first conveyance roller 201.

[0115] Next, as shown in FIGS. 17(a) and 17(b), the pair of alignment plates 401 and 402 align the sheet S11. At this time, since the sheet S11 is shifted to the front side, the front alignment plate 401 is moved 10 mm to the rear side without moving the rear alignment plate 402. In this state, the pair of alignment plates 401 and 402 are in the aligned positions. Here, since the receiving positions of the alignment plates 401 and 402 are positions 5 mm apart from the positions of the widthwise ends of the sheet at the reference position (the position determined in terms of control) at the time of shift discharge, the front alignment plate 401 is moved 10 mm to the rear side. Note that the positions of the widthwise ends of the sheet at the reference position vary depending on the size of the sheet.

[0116] Also, during the alignment of the sheet S11, the paddle 275 is raised to the upper position. The timing of raising the paddle 275 is before the alignment plate 401 reaches the alignment position. In the present embodiment, the alignment plate 401 reaches the alignment position after the paddle 275 is separated from the upper surface of the sheet. The timing of starting the raising of the paddle 275 from the conveyance position and the timing of starting the movement of either or both of the alignment plates 401 and 402 from the receiving position to the alignment position are after a predetermined time has elapsed since the rear end of the sheet has passed through the sheet end detection sensor SN3.

[0117] During the alignment of the first sheet S11 by the pair of alignment plates 401 and 402, the second sheet S12 starts to be discharged from the discharge roller pair 42. At this time, the second sheet S12 may be discharged while being displaced in the width direction with respect to the sheet S11 being aligned. For example, in FIG. 17(b), the sheet S12 is discharged with a slight shift to the front side with respect to the sheet S11. Therefore, the sheet S12 discharged from the discharge roller pair 42 is guided above the alignment surface 4001 by the guide surface 4002 of the front alignment plate 401. In FIG. 17(a), the rear alignment plate 402 is shown, and it appears that the sheet S12 is placed on the rear alignment plate 402, but as shown in FIG. 17(b), the sheet S12 is not placed on the rear alignment plate 402. Also, with the second sheet S12 being discharged, the third sheet S13 is shifted to the front side by the second conveying roller 202 and the third conveying roller 203.

[0118] In the apparatus of this embodiment, the tolerance of the shift amount due to the tolerance of the shift amount by the second conveying roller 202 and the third conveying roller 203 is 5 mm. The front alignment plate 401 during alignment has moved 10 mm to the rear side from the receiving position of the sheet S1, and the alignment plate 401 at the receiving position is at a position 5 mm away from the widthwise end of the sheet at the reference position to the front side. Therefore, the position of the front alignment plate 401 at the alignment position is 5 mm shifted to the rear side from the widthwise end of the sheet at the reference position. Thus, when the sheet is shifted 5 mm to the front side, which is the maximum amount of the tolerance, from the widthwise end of the sheet at the reference position by the second conveying roller 202 and the third conveying roller 203 and the sheet is discharged from the discharge roller pair 42 in this state, this sheet may be discharged with a maximum shift of 10 mm to the front side with respect to the alignment surface 4001 of the front alignment plate 401.

[0119] Therefore, in this embodiment, the thickness in the width direction of the guide surface 4002 is set to 10 mm or more, for example, 11 mm. Thus, even if the second sheet S12 is displaced by 5 mm, which is the tolerance of the shift amount by the second conveying roller 202 and the third conveying roller 203, and is discharged from the discharge roller pair 42, the sheet S12 can be guided by the guide surface 4002.

[0120] Next, as shown in FIGS. 18(a) and 18(b), when the alignment operation of the sheet S11 is completed, the front alignment plate 401 is moved from the alignment position to the sheet receiving position. Specifically, the alignment plate 401 is moved 10 mm to the front side from the alignment position. At this time, the rear alignment plate 402 does not move. At this time, the second sheet S12 can fall onto the first sheet S11, being displaced from the guide surface 4002 of the front alignment plate 401. Then, when the rear end of the second sheet S12 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveying position, and while dropping the sheet S12 with the paddle 275, it is scraped toward the abutting member 271. Further, similar to when aligning the first sheet S11, the front alignment plate 401 is moved to the alignment position to align the sheet S12.

[0121] The above operation is performed on the subsequent sheets included in the first sheet bundle, and as shown in FIGS. 19(a) and 19(b), the first sheet bundle is stacked on the first tray 49. Here, the first sheet S21 of the second sheet bundle is continuously conveyed following the first sheet bundle, and the second sheet bundle is stacked with a shift to the rear side with respect to the first sheet bundle. For this reason, the positions in the width direction of the alignment plates 401 and 402 for aligning the second sheet bundle are different from the positions for aligning the first sheet bundle. Therefore, in this embodiment, before performing the discharge operation of the second sheet bundle, the pair of alignment plates 401 and 402 is raised. That is, the stacker control unit 330 raises the pair of alignment plates 401 and 402 from the first position to the second position by the jogger lift motor MT19 before discharging the next sheet from the discharge roller pair 42 with a shift to one side in the width direction (here, the rear side) with respect to the first sheet bundle composed of a plurality of sheets stacked on the first tray 49.

[0122] Since the distance between the last sheet of the first stack of sheets and the first sheet S21 of the second stack of sheets is the same as the distance between the plurality of sheets in the first stack of sheets, if the pair of alignment plates 401 and 402 are raised as described above before the discharging operation of the second stack of sheets, the discharging operation of the first sheet S21 will not be in time, and there is a risk that the sheet S21 will come into contact with the alignment plates 401 and 402. Therefore, in the present embodiment, as shown in FIGS. 19(a) and (b), the sheet S21 is temporarily made to wait in a buffer path 39 branched from between the second conveying roller 202 and the third conveying roller 203. And the timing of discharging the first sheet S21 of the second stack of sheets by the discharge roller pair 42 is delayed.

[0123] That is, when the stacker control unit 330 stacks the second stack of sheets including the first sheet S21 (the first sheet) and the second sheet S22 (the second sheet) on the first tray 49 by shifting the first stack of sheets loaded on the first tray 49 to one side (here, the rear side) in the width direction, the sheet S21 is temporarily made to wait in the buffer path 39. Then, the third conveying roller 203 and the pre-processing roller 36 as the buffer conveying unit convey the sheet S22 together with the sheet S21 toward the discharge roller pair 42. Specifically, the sheet S21 waiting in the buffer path 39 is conveyed by the conveying roller 208 toward the straight path 28 and merged with the next sheet S22 being conveyed in the straight path 28. Then, the third conveying roller 203 and the pre-processing roller 36 convey the sheet S21 and the sheet S22 in a stacked state toward the discharge roller pair 42.

[0124] In this embodiment, the conveying roller 208 is also a shift roller capable of moving the sheet in the width direction. Therefore, with the first sheet S21 nipped between the third conveying roller 203 and the conveying roller 208, the sheet S21 can be shifted to the front side and the rear side. For this reason, while the third conveying roller 203 nips the sheets S21 and S22, with the sheet S21 nipped by the conveying roller 208 and the sheet S22 nipped by the second conveying roller 202, by moving the second conveying roller 202, the third conveying roller 203, and the conveying roller 203 in the same direction, it is possible to shift the sheets S21 and S22 in a state where they are overlapped. In FIGS. 19(a) and (b), the sheets S21 and S22 are shifted to the rear side in a state where they are overlapped.

[0125] As shown in FIGS. 20(a) and (b), before the first and second sheets S21 and S22 of the second sheet bundle are discharged from the discharge roller pair 42, the pair of alignment plates 401 and 402 are raised to the second position. As described above, in this embodiment, the pair of alignment plates 401 and 402 are rotatably connected to the pair of swing arms 403 and 404 about the rotation axis 465, and extend upstream of the discharge direction from the rotation axis 465. And in such a configuration, the angle θ formed by the first virtual line α1 and the second virtual line α2 is made smaller at the second position shown in FIG. 20(a) than at the first position shown in FIG. 19(a). That is, when the swing arms 403 and 404 are swung upward to move the alignment plates 401 and 402 to the second position, the angles of the alignment plates 401 and 402 with respect to the swing arms 403 and 404 change so that the alignment plates 401 and 402 and the swing arms 403 and 404 are folded.

[0126] Here, when the angle θ formed by the first virtual line α1 and the second virtual line α2 is the same at the first position and the second position, unless the swing amounts of the swing arms 403 and 404 are increased, the alignment plates 401 and 402 do not move far enough away from the first position, so it takes a long time for the alignment plates 401 and 402 to reach the second position. In contrast, in the present embodiment, the angle θ formed by the first virtual line α1 and the second virtual line α2 is made smaller at the second position than at the first position. Therefore, even if the amount by which the swing arms 403 and 404 swing upward is small, the alignment plates 401 and 402 can be moved to a position far enough away from the first position. Accordingly, the swing amounts of the swing arms 403 and 404 until the alignment plates 401 and 402 are moved from the first position to the second position can be reduced, and the time taken for the alignment plates 401 and 402 to rise to the second position can be shortened.

[0127] Also, in the present embodiment, as described above, the angle θ formed by the first virtual line α1 and the second virtual line α2 at the first position is an acute angle. For this reason, the change amount of the angle θ when moving from the first position to the second position can be made small. That is, the swing amounts of the swing arms 403 and 404 to the second position can be reduced. As a result, the time taken for the alignment plates 401 and 402 to rise to the second position can be made even shorter. In order to make the angle θ an acute angle, it is preferable to make the lengths of the swing arms 403 and 404 sufficiently long, that is, to increase the distance between the swing shaft 405 and the rotation shaft 465. For this purpose, it is preferable to bring the position of the swing shaft 405 regarding the discharge direction as close as possible to the discharge roller pair 42. Thereby, even if the angle θ is small, it becomes possible to position the alignment plates 401 and 402 at the first position.

[0128] If the alignment plates 401 and 402 can be raised from the first position to the second position in a short time, by only temporarily waiting for the first sheet S21 of the second sheet bundle, the raising operation of the alignment plates 401 and 402 to the second position can be made in time before the discharging operation of this first sheet S21. That is, if the alignment plates 401 and 402 cannot be raised from the first position to the second position in a short time, for example, there is a possibility that the conveyance of the first sheet S21 of the second sheet bundle needs to be stopped and the conveyance of the sheet S21 cannot be started until waiting for the alignment plates 401 and 402 to rise to the second position. In this case, the productivity in the shift discharging mode will decrease. On the contrary, in the present embodiment, since the alignment plates 401 and 402 can be raised from the first position to the second position in a short time, the productivity can be improved.

[0129] Also, in the present embodiment, as shown in FIGS. 20(a) and (b), after raising the alignment plates 401 and 402 to the second position, the alignment plates 401 and 402 are moved to the rear side. That is, since the second sheet bundle is shifted to the rear side and discharged, the alignment plates 401 and 402 are moved to the rear side accordingly. If the alignment plates 401 and 402 are moved to the rear side at the first position, the stacking property of the already stacked first sheet bundle will be disturbed. Therefore, the alignment plates 401 and 402 are moved to the rear side after being raised to the second position. Note that even if the second position has not been reached, if the alignment plates 401 and 402 are separated from the topmost sheet of the already stacked first sheet bundle, the alignment plates 401 and 402 may be moved to the rear side during the raising.

[0130] Next, as shown in FIGS. 21(a) and (b), when the rear ends of the sheets S21 and S22 pass through the discharge roller pair 42, the paddle 275 is lowered to the conveyance position, and while dropping the sheets S21 and S22 by the paddle 275, they are scraped toward the abutting member 271. At this time, the third sheet S23 of the second sheet bundle is conveyed to the pre-processing roller 36 in a state of being shifted to the rear side.

[0131] Next, as shown in FIGS. 22(a) and (b), the pair of alignment plates 401 and 402 are used to align the sheets S21 and S22. At this time, since the sheets S21 and S22 are shifted toward the rear side, without moving the front alignment plate 401, the rear alignment plate 402 is moved 10 mm toward the front side. In this state, the pair of alignment plates 401 and 402 are in the aligned positions. Also, during the alignment of the sheets S21 and S22, the paddle 275 is raised to the upper position.

[0132] During the alignment of the first and second sheets S21 and S22 by the pair of alignment plates 401 and 402, the third sheet S23 starts to be discharged from the discharge roller pair 42. Also in this case, similar to the case described with reference to FIGS. 17(a) and (b), when the sheet S23 is discharged with a slight shift toward the rear side with respect to the sheets S21 and S22, the sheet S23 is guided above the alignment surface 4001 by the guide surface 4002 of the rear alignment plate 402. When the alignment operation of the sheets S21 and S22 is completed, the rear alignment plate 402 is moved from the aligned position to the sheet receiving position, and further, the paddle 275 is lowered to the conveying position to scrape the third sheet S23 while dropping it toward the abutting member 271. Further, similar to the case during the alignment of the sheets S21 and S22, the rear alignment plate 402 is moved to the aligned position to align the sheet S23. Such an operation is performed until the last sheet of the second sheet bundle. During the discharge of the last sheet, the alignment plates 401 and 402 are returned to the receiving position. When the rear end of the last sheet passes through the discharge roller pair 42, the rear alignment plate 402 is moved toward the front side to align the last sheet, and the job is completed. At the end of the job, the pair of alignment plates 401 and 402 are returned to the home position. The positions of the alignment plates 401 and 402 at the end of the job will be described later.

[0133] [Straight Discharge Mode] Next, without shifting the sheet and without performing the binding process, the sheet is discharged onto the first tray 49 to form a stack of sheets consisting of a plurality of unbound sheets, and the straight discharge mode will be described. In the straight discharge mode, for example, as shown in FIG. 30(a), a plurality of unbound sheet stacks are discharged onto the first tray 49 without being shifted. An example of such a straight discharge mode will be described with reference to FIGS. 23(a) to 27(b). Note that the basic operations of each part are the same as those in the above-described shift discharge mode, but it is different from the shift discharge mode in that the sheet is discharged without being shifted. However, even in the straight discharge mode, a shift operation may be performed to align the center position in the width direction of the sheet with the center position in the width direction of the straight path 28.

[0134] The stacker control unit 330 is capable of executing the straight discharge mode, and when the straight discharge mode is executed, the pair of alignment plates 401 and 402 are operated as follows. First, as shown in FIGS. 23(a) and (b), the sheet S1 conveyed to the straight path 28 passes through the first conveying roller 201, and the position of the edge (side edge) in the width direction of the sheet S1 is detected by the registration detection sensor SN2. At this time, the pair of alignment plates 401 and 402 are located at the sheet receiving position in the straight discharge mode from the home position shown in FIGS. 6 and 7. That is, the pair of alignment plates 401 and 402 move from the second position to the first position in the vertical direction, and in the width direction, they are positions separated by 5 mm from the width direction end (side edge) of the sheet at the position (reference position) where the sheet S1 is stacked on the first tray 49. In FIGS. 23(a) and (b), the alignment plates 401 and 402 are in positions when discharging the sheet based on the center in the width direction.

[0135] Next, as shown in FIGS. 24(a) and (b), based on the detection result of the registration detection sensor SN2, the stacker control unit 330 aligns the center position in the width direction of the sheet S1 and the center position in the width direction of the straight path 28 by the second conveyance roller 202 and the third conveyance roller 203. The center position in the width direction of the straight path 28 is the same as the center position in the width direction of the discharge roller pair 42 and the center position in the width direction of the first tray 49. Then, the sheet S1 is delivered to the pre-processing roller 36 and further conveyed from the pre-processing roller 36 toward the discharge roller pair 42. At this time, the lower surface of the sheet S1 heading toward the discharge roller pair 42 is supported by the guide surface 270a formed on the upper surfaces of the pair of alignment plates 270 on the processing tray 37. Then, the sheet S1 is discharged from the discharge roller pair 42 while being supported by the guide surface 270a.

[0136] Next, as shown in FIGS. 25(a) and (b), when the rear end (the upstream end in the conveyance direction) of the sheet S1 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveyance position, and the sheet S1 is conveyed upstream in the discharge direction while being dropped onto the first tray 49 by the paddle 275. That is, the sheet S1 is scraped in by the paddle 275, and the rear end of the sheet S1 is abutted against the abutting member 271. At this time, the second sheet S2 is conveyed to the pre-processing roller 36 with the center position in the width direction aligned with the center position in the width direction of the straight path 28, and the third sheet S3 has reached the first conveyance roller 201.

[0137] Next, as shown in FIGS. 26(a) and 26(b), the alignment of the sheet S1 is performed by a pair of alignment plates 401 and 402. At this time, similar to the case described in the shift discharge mode, the paddle 275 is separated from the upper surface of the sheet S1, and then the alignment plates 401 and 402 reach the alignment position. In the present embodiment, the alignment of the sheet S1 is performed by bringing the pair of alignment plates 401 and 402 into contact with both sides in the width direction of the sheet S1. During the alignment of the first sheet S1 by the pair of alignment plates 401 and 402, the second sheet S2 starts to be discharged from the pair of discharge rollers 42. At this time, due to the tolerance of the shift amount (5 mm) due to the tolerance of the shift amount by the second conveyance roller 202 and the third conveyance roller 203 described above, the second sheet S2 may be discharged while being displaced in the width direction with respect to the sheet S1 being aligned.

[0138] When the second sheet S2 is discharged while being displaced in the width direction, the leading end of the sheet S2 contacts the guide surface 4002 at any of the following timings. (1) While the alignment plates 401 and 402 move to the alignment position and the alignment surface 4001 contacts the side edge of the first sheet S1 to perform widthwise alignment. In the present embodiment, the time during this period is set to 50 ms. (2) After the alignment is completed and the alignment plates 401 and 402 are moving from the alignment position toward the receiving position. In the present embodiment, the time during this period is set to 30 ms.

[0139] And in any case, the sheet S2 is guided above the alignment surface 4001 by any of the guide surfaces 4002 of the alignment plates 401 and 402. That is, when the sheet S2 is displaced to the front side, it is guided by the guide surface 4002 of the front alignment plate 401, and when the sheet S2 is displaced to the rear side, it is guided by the guide surface 4002 of the rear alignment plate 402.

[0140] That is, the guide surface 4002 allows the leading edge of the next sheet to be received when the alignment plates 401 and 402 are in the aligned position or during the movement from the aligned position to the receiving position. In other words, when the alignment plates 401 and 402 are in any of the positions (1) and (2) described above and the leading edge of the next sheet reaches the downstream side of the upstream end of the alignment surface 4001 of the alignment plates 401 and 402 in the discharge direction (the direction along the nip line N2), the next sheet is guided by the guide surface 4002.

[0141] Also, until the alignment plates 401 and 402 move from the receiving position to the aligned position when aligning the first sheet, the leading edge of the next sheet does not reach the upstream end of the alignment surface 4001 of the alignment plates 401 and 402. This is because if the leading edge of the next sheet reaches the alignment surface area β (Fig. 26(a)) before the alignment plates 401 and 402 reach the aligned position, the next sheet will be nipped by the discharge roller pair 42 and then hit against the alignment surface 4001, which may damage the sheet.

[0142] Next, as shown in Figs. 27(a) and (b), after the alignment operation of the sheet S1 is completed, the alignment plates 401 and 402 are moved from the aligned position to the sheet receiving position. Then, when the trailing edge of the second sheet S2 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveying position, and the paddle 275 scrapes the sheet S2 while dropping it toward the abutting member 271. Further, in the same manner as when aligning the first sheet S1, the alignment plates 401 and 402 are moved to the aligned position to align the sheet S2. At this time, the third sheet S3 has been conveyed to the pre-processing roller 36.

[0143] For the sheet S3 as well, it is guided by the guide surface 4002 of either the alignment plates 401 or 402, and similar to the sheet S2, the alignment in the width direction is performed by the alignment plates 401 and 402. Such an operation is carried out until the last sheet of the sheet bundle. During the discharge of the last sheet, the alignment plates 401 and 402 are returned to the receiving position. When the rear end of the last sheet has passed through the discharge roller pair 42, the alignment plates 401 and 402 are moved to the alignment position to align the last sheet, and the job is terminated. At the end of the job, the pair of alignment plates 401 and 402 are returned to the home position. The positions of the alignment plates 401 and 402 at the end of the job will be described later.

[0144] As described above, in this embodiment, in either the shift discharge mode or the straight discharge mode, even when discharging a plurality of consecutive sheets with a reduced interval to the first tray 49, the alignment of the sheets by the alignment plates 401 and 402 is possible. Therefore, the productivity of the apparatus can be improved.

[0145] In the straight discharge mode of this embodiment, the aspect where both the alignment plates 401 and 402 are moved from the receiving position to the alignment position during sheet alignment has been shown. However, for example, during sheet alignment, the alignment plate 401 can be fixed at a position where the sheet will not hit even if it is displaced toward the alignment plate 401 side during discharge, and only the alignment plate 402 is moved from the receiving position toward the alignment plate 401 side to align the discharged sheet by abutting it against the alignment plate 401, and then the alignment plate 402 is moved to the receiving position. In that case, since the alignment plate 402 is the one that the next sheet may hit during the alignment operation, the guide surface 4002 may be provided only on the alignment plate 402.

[0146] [Position of the alignment plate at the end of the job] Next, with reference to FIGS. 28 to 29(b), the positions of the alignment plates 401 and 402 at the end of the job will be described. When a job of loading sheets on the first tray 49 including each mode as described above is completed, the alignment plates 401 and 402 are positioned at the home position. Here, when the home positions of the alignment plates 401 and 402 are located outside the alignment position in the width direction, for example, further outside the sheet receiving position, there is a risk that the alignment plates 401 and 402 will interfere when the operator takes out the sheet or stack of sheets on the first tray 49.

[0147] Therefore, in the present embodiment, one of the pair of alignment plates 401 and 402 (for example, the front alignment plate 401) moves to the other side in the width direction (for example, the rear side) from one end in the width direction (for example, the front end) of the sheet S loaded on the first tray 49 after the job of loading sheets on the first tray 49 is completed and the plate has risen from the first position to the second position. Also, in the present embodiment, the other alignment plate of the pair of alignment plates 401 and 402 (for example, the rear alignment plate 402) also moves to one side in the width direction (for example, the front side) from the other end in the width direction (for example, the rear end) of the sheet S loaded on the first tray 49 after the job is completed and the plate has risen from the first position to the second position. That is, as shown in FIGS. 28 and 29(a), both of the pair of alignment plates 401 and 402 are raised from the first position to the second position at the end of the job and are positioned inside both ends in the width direction of the sheet S loaded on the first tray 49. In the present embodiment, this state is defined as the home position of the pair of alignment plates 401 and 402.

[0148] Note that the positions of the alignment plates 401 and 402 in the width direction at their home positions are preferably inside the both ends in the width direction of the sheet with the minimum size processable by the apparatus. However, considering the frequency of use, the positions of the alignment plates 401 and 402 in the width direction at their home positions may be made inside the both ends in the width direction of a sheet (for example, A4 size) larger than the sheet with the minimum size. Also, regardless of the size of the sheet loaded on the first tray 49, it is preferable that the positions of the alignment plates 401 and 402 in the width direction at their home positions be at predetermined positions. Also, the loading position of the sheet serving as a reference at this time is the case where the sheet is discharged with the center in the width direction as a reference.

[0149] Also, considering the case where the sheet is discharged in the shift discharge mode, the positions of the alignment plates 401 and 402 in the width direction at their home positions may be made inside the both ends in the width direction of the sheet regardless of the direction in which the sheet shifts. That is, when the sheet shifts to the front side and is loaded on the first tray 49, the position of the rear alignment plate 402 is made inside the rear end of the sheet, and when the sheet shifts to the rear side and is loaded on the first tray 49, the position of the front alignment plate 401 is made inside the front end of the sheet. In any case, the pair of alignment plates 401 and 402 are positioned inside the both ends in the width direction of the sheet.

[0150] By defining the positions of the alignment plates 401 and 402 in the width direction at their home positions in this way, when the operator takes out the sheet or the stack of sheets loaded on the first tray 49, the alignment plates 401 and 402 are less likely to get in the way, and the removability of the sheet or the stack of sheets from the first tray 49 can be improved. In particular, since the alignment plates 401 and 402 on both sides are positioned inside the both ends in the width direction of the sheet, when the number of sheets in the stack of sheets is large, it is easy to grasp and take out the sheets from the front side and the rear side with both hands.

[0151] Note that, as shown in FIG. 29(b), at least only the front alignment plate 401 may be moved to the rear side in the width direction with respect to the front end portion in the width direction of the sheet stacked on the first tray 49 after the job is completed and the sheet is lifted from the first position to the second position. In this case, the position of the rear alignment plate 402 in the width direction may be a position separated outward from the alignment position in the width direction, for example, a position further outward than the sheet receiving position. Since the operator often takes out the sheet or the stack of sheets on the first tray 49 from the front side, even if the front alignment plate 401 is simply positioned inside the width direction end portion of the sheet in this way, the removability of the sheet or the stack of sheets from the first tray 49 can be improved.

[0152] Also, even during the standby of the job, the positions of the alignment plates 401 and 402 in the width direction may be the same as the positions at the end of the above-described job. That is, it is preferable to position the alignment plates 401 and 402 at the home position even during the standby of the job. During the standby of the job, the power of the apparatus is ON, but the job is not being executed and it is in a standby state. Also, during the standby of the job, a sleep state with less power consumption than the standby state may be included.

[0153] [Another Example of Alignment Plate] The pair of alignment plates 401 and 402 described above are connected via swing arms 403 and 404 and a rotation shaft 465 at the end portions in the longitudinal direction of the alignment plates 401 and 402 (the direction extending upstream in the discharge direction from the rotation shaft 465). However, the position where the alignment plate is connected to the swing arm is not limited to the end portion in the longitudinal direction. For example, as shown in FIG. 31, it may be connected via a swing arm 404A (403A) and a rotation shaft 465 at an intermediate portion in the longitudinal direction of the alignment plate 402A (401A). FIG. 31 shows the rear alignment plate 402A and the swing arm 404A, but the same applies to the front alignment plate 401A and the swing arm 403.

[0154] Regarding the alignment plate 402A (401A) shown in FIG. 31, it is also rotatably connected to the swing arm 404A (403A) about the rotation axis 465, and extends upstream and downstream of the discharge direction from the rotation axis 465. Further, the alignment plate 402A (401A) includes a guide surface 4012 as a guide portion and a sheet receiving surface 4013 as an upstream guide portion, similar to the alignment plates 401 and 402. Even when the next sheet is discharged during sheet alignment, the next sheet can be guided above the alignment surface 4011 that aligns the sheets.

[0155] <Second Embodiment> The second embodiment will be described with reference to FIGS. 32(a) to (c). In the above-described first embodiment, an example in which the guide surface 4002 as an accommodating portion is formed integrally with the pair of alignment plates 401 and 402 has been described. In contrast, in this embodiment, the support member 4020 as an accommodating portion is separate from the pair of alignment plates 401 and 402. Since the other configurations and operations are the same as those of the first embodiment described above, the same reference numerals are given to the same configurations, and the description and illustration are omitted or simplified. Hereinafter, the differences from the first embodiment will be mainly described.

[0156] As shown in FIG. 32(b), the support member 4020 as an accommodating portion is movable between an accommodating position that allows temporary reception of the next sheet and a retracted position that is retracted from the accommodating position as shown in FIGS. 32(a) and (c). The accommodating position is a position above the upstream end portion in the discharge direction of the pair of alignment plates 401 and 402 in a state where the pair of alignment plates 401 and 402 are in the alignment position. Further, the retracted position is a position further below the rotation axis 48a of the lower conveyance roller 48 among the upper conveyance roller 41 and the lower conveyance roller 48.

[0157] The support member 4020 is driven by a drive source such as a motor (not shown) and is slidable between the above-described allowable position and the retracted position. For this reason, an opening through which the support member 4020 can pass is formed in the abutting member 271. The support member 4020 moves between the retracted position inside the apparatus housing 27 (FIG. 2) and the allowable position protruding from the apparatus housing 27 toward the first tray 49 side through this opening.

[0158] Also, in the present embodiment, a pair of support members 4020 are provided corresponding to the pair of alignment plates 401 and 402. That is, the pair of support members 4020 are arranged spaced apart in the width direction. The positions and lengths of the pair of support members 4020 in the width direction are configured to cover the movable ranges of the pair of alignment plates 401 and 402, respectively. That is, the support member 4020 corresponding to the front alignment plate 401 is located above the upstream end portion in the discharge direction of the alignment plate 401 at the allowable position regardless of the position of the alignment plate 401 within the movable range, and is configured to guide the sheet discharged from the discharge roller pair 42 above the alignment surface 4001. Similarly, the support member 4020 corresponding to the rear alignment plate 402 is located above the upstream end portion in the discharge direction of the alignment plate 402 at the allowable position regardless of the position of the alignment plate 402 within the movable range, and is configured to guide the sheet discharged from the discharge roller pair 42 above the alignment surface 4001. Note that the pair of support members 4020 may be a single support member 4020. In this case, one support member 4020 covers the movable ranges of the pair of alignment plates 401 and 402.

[0159] Next, the operation of the support member 4020 will be described. The operation of the support member 4020 is the same regardless of whether it is in the shift discharge mode or the straight discharge mode. First, as shown in Fig. 32(a), when the rear end (the upstream end in the conveyance direction) of the first sheet S1 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveyance position, and the sheet S1 is conveyed upstream in the discharge direction while being dropped onto the first tray 49 by the paddle 275. That is, the paddle 275 scrapes in the sheet S1 and abuts the rear end of the sheet S1 against the abutting member 271. At this time, the support member 4020 is located at the retracted position. Also, the second sheet S2 has been conveyed to the pre-processing roller 36, and the third sheet S3 has reached the first conveyance roller 201.

[0160] Next, as shown in Fig. 32(b), the alignment of the sheet S1 is performed by the pair of alignment plates 401 and 402. At this time, the alignment plates 401 and 402 reach the alignment position after the paddle 275 is separated from the upper surface of the sheet S1. Further, when the pair of alignment plates 401 and 402 are aligning the sheet S1, the support member 4020 moves from the retracted position to the allowable position. The timing at which the support member 4020 moves to the allowable position is, for example, the timing at which the paddle 275 rises. During the alignment of the first sheet S1 by the pair of alignment plates 401 and 402, the second sheet S2 starts to be discharged from the discharge roller pair 42.

[0161] When the second sheet S2 is discharged in a state of being displaced in the width direction with respect to the sheet S1 being aligned, the leading end of the sheet S2 is guided by the upper surface 4021 of the support member 4020 as shown in Fig. 32(b). That is, the support member 4020 allows the temporary acceptance of the next sheet S2 above the first tray 49 when the pair of alignment plates 401 and 402 are aligning the sheet S1.

[0162] Next, as shown in FIG. 32(c), when the alignment operation of the sheet S1 is completed, the alignment plates 401 and 402 are moved from the alignment position to the sheet receiving position. At this time, the support member 4020 moves from the allowable position to the retracted position. The timing at which the support member 4020 moves to the retracted position is after the alignment plates 401 and 402 start moving from the alignment position. For example, it may be during the movement of the alignment plates 401 and 402, or it may be after the alignment plates 401 and 402 move to the receiving position. However, it is preferable that the movement of the support member 4020 to the retracted position is completed before the rear end of the second sheet S2 passes through the discharge roller pair 42. Then, when the rear end of the second sheet S2 passes through the discharge roller pair 42, the paddle 275 is lowered to the conveying position, and the sheet S2 is scraped toward the abutting member 271 while being dropped by the paddle 275. Further, similar to the alignment of the first sheet S1, the alignment plates 401 and 402 are moved to the alignment position to align the sheet S2. Thereafter, the above-described operations are repeated until the last sheet of the sheet bundle, and a sheet bundle is formed on the first tray 49.

[0163] Also in the case of such an embodiment of the present invention, similar to the first embodiment, in any of the shift discharge mode and the straight discharge mode, even when discharging to the first tray 49 with the interval between a plurality of consecutive sheets shortened, the sheets can be aligned by the alignment plates 401 and 402. Therefore, the productivity of the apparatus can be improved. However, in the first embodiment, since the guide surface 4002 as the allowable portion is formed integrally with the pair of alignment plates 401 and 402, the first embodiment can achieve a lower cost than this embodiment.

[0164] <Other Embodiments> In the above-described embodiment, a configuration in which binding processing is performed as predetermined processing performed by the processing unit has been described. However, the predetermined processing is not limited to binding processing, and may be folding processing, shifting processing, punching processing, creasing (making a fold), laminating processing, or the like. Further, in the above-described embodiment, an example in which control around the first tray 49 of the sheet processing apparatus B is performed by the stacker control unit 330 (CPU 331) has been described. However, this control may be performed by the control unit 310 (CPU 311) of the image forming apparatus A.

[0165] Further, the disclosure of the present embodiment includes the following configurations. (Configuration 1) A stacking tray for stacking sheets, A lowering unit that lowers the stacking tray according to the stacking of the sheets, A conveying unit that conveys the sheets toward the stacking tray, A first acting unit and a second acting unit that act on both end edges in the width direction of the sheet bundle to align the sheet bundle stacked on the stacking tray, An allowing unit that allows temporary acceptance of the next sheet above the stacking tray when the first acting unit and the second acting unit are aligning the sheet bundle, A sheet stacking apparatus having the above. (Configuration 2) The sheet stacking apparatus according to Configuration 1, wherein the first acting unit and the second acting unit align the next sheet together with the sheet bundle aligned when the next sheet is temporarily accepted by the allowing unit. (Configuration 3) The first acting unit and the second acting unit each have an aligning portion that contacts both end edges in the width direction of the sheet bundle when aligning the sheet bundle, The sheet stacking apparatus according to Configuration 1 or 2, wherein the allowing unit is formed on the upper surface of the aligning portion. (Configuration 4) The aligning portion has a first portion and a second portion upstream of the first portion with respect to the conveying direction of the sheets by the conveying unit, The sheet stacking apparatus according to Configuration 3, wherein the first portion has a longer vertical length than the second portion. (Configuration 5) At least one of the first acting portion and the second acting portion is movable between an alignment position for aligning the sheet bundle in the width direction and a position farther from the width direction edge of the sheet bundle than the alignment position. The conveying unit is a pair of conveying rollers that sandwich and convey the sheet. The upstream end portion of the receiving portion in the conveying direction of the sheet by the conveying unit is located below the line obtained by extending the nip surface of the pair of conveying rollers downstream in the conveying direction in a state where the first acting portion and the second acting portion are in the alignment position. The sheet stacking device according to Configuration 3 or 4. (Configuration 6) At least one of the first acting portion and the second acting portion is movable between an alignment position for aligning the sheet bundle in the width direction and a position farther from the width direction edge of the sheet bundle than the alignment position. In a state where the first acting portion and the second acting portion are in the alignment position, it is provided at the upstream end portion of the receiving portion in the conveying direction of the sheet by the conveying unit, and as it goes downstream in the conveying direction, it goes downward so as to go inward, which is the side where the sheet bundle is located in the width direction. The sheet stacking device according to any one of Configurations 3 to 5, which includes an inclined portion that inclines. (Configuration 7) The receiving portion of the sheet stacking device according to Configuration 1 is movable between a receiving position for temporarily receiving the next sheet and a retracted position retracted from the receiving position. (Configuration 8) The conveying unit is a pair of conveying rollers that sandwich and convey the sheet. At least one of the first acting portion and the second acting portion is movable between an alignment position for aligning the sheet bundle in the width direction and a position farther from the width direction edge of the sheet bundle than the alignment position. The receiving position is a position above the upstream end portion of the first acting portion and the second acting portion in the conveying direction of the sheet by the conveying unit in a state where the first acting portion and the second acting portion are in the alignment position. The sheet stacking device according to Configuration 7, wherein the storage position is a position further below the rotation axis of the lower conveying roller among the pair of conveying rollers. (Configuration 9) An image forming unit that forms an image on a sheet, A stacking tray that stacks the sheet on which the image is formed by the image forming unit, A lowering unit that lowers the stacking tray according to the stacking of the sheets, A conveying unit that conveys the sheet toward the stacking tray, A first acting unit and a second acting unit that act on both end edges in the width direction of the sheet bundle to align the sheet bundle stacked on the stacking tray, An allowing unit that allows temporary acceptance of the next sheet above the stacking tray when the first acting unit and the second acting unit are aligning the sheet bundle, An image forming system having the above.

Explanation of Signs

[0166] 3 ··· Image forming unit 42 ··· Discharge roller pair (conveying unit) 49 ··· First tray (stacking tray) 401, 402, 401A, 402A ··· Alignment plates (first acting unit, second acting unit) 4001, 4011 ··· Alignment surfaces (alignment unit) 4002, 4012 ··· Guide surfaces (allowing unit) 4003, 4013 ··· Sheet receiving surfaces (inclined unit) 4020 ··· Support member (allowing unit) 1000 ··· Image forming system A ··· Image forming apparatus B ··· Sheet processing apparatus MT18 ··· Tray lifting motor (lowering unit)

Claims

1. A loading tray for loading sheets; a lowering section that lowers the stacking tray in response to the stacking of sheets; a conveying section that conveys a sheet toward the stacking tray; a first acting portion and a second acting portion acting on both ends of the sheet stack in a width direction to align the sheet stack stacked on the stacking tray; an allowance portion that allows a next sheet to be temporarily received above the stack tray when the first action portion and the second action portion are aligning the sheet stack; A sheet loading device having

2. 2. The sheet stacking device according to claim 1, wherein the first and second acting portions align the next sheet temporarily accepted by the allowing portion together with the sheet stack that was aligned when the next sheet was temporarily accepted.

3. the first and second acting portions each have an alignment portion that comes into contact with both widthwise ends of the sheet stack when aligning the sheet stack; The sheet stacking device according to claim 1 , wherein the tolerance portion is formed on an upper surface of the alignment portion.

4. the alignment unit has a first portion and a second portion located upstream of the first portion in a conveying direction of the sheet by the conveying unit, The sheet stacking device according to claim 3 , wherein the first portion has a vertical length longer than that of the second portion.

5. At least one of the first and second action portions is movable between an alignment position where the sheet stack is aligned in the width direction and a position farther away from an edge of the sheet stack in the width direction than the alignment position; the conveying section is a pair of conveying rollers that sandwich and convey a sheet, A sheet stacking device as described in claim 3, wherein the upstream end of the allowing portion in the sheet transport direction by the transport portion is located below a line extending downstream in the transport direction from the nip surface of the pair of transport rollers when the first acting portion and the second acting portion are in the alignment position.

6. At least one of the first and second action portions is movable between an alignment position where the sheet stack is aligned in the width direction and a position farther away from an edge of the sheet stack in the width direction than the alignment position; A sheet stacking device as described in claim 3, wherein when the first and second acting portions are in the alignment position, the allowing portion is provided at an upstream end of the sheet conveying direction by the conveying portion, and is inclined downward as it moves toward the downstream side in the conveying direction and toward the inside on which the sheet stack is located in the width direction.

7. 2. The sheet stacking device according to claim 1, wherein the allowing portion is movable between an allowing position where the next sheet is allowed to be temporarily received and a retracted position retracted from the allowing position.

8. the conveying section is a pair of conveying rollers that sandwich and convey a sheet, At least one of the first and second action portions is movable between an alignment position where the sheet stack is aligned in the width direction and a position farther away from an edge of the sheet stack in the width direction than the alignment position; the permissible position is a position above an upstream end of the first action portion and the second action portion in a conveying direction of the sheet by the conveying portion when the first action portion and the second action portion are in the alignment position, 8. The sheet stacking device according to claim 7, wherein the retracted position is a position further below a rotation axis of a lower conveying roller of the pair of conveying rollers.

9. an image forming unit that forms an image on a sheet; a stacking tray for stacking sheets on which images have been formed by the image forming unit; a lowering section that lowers the stacking tray in response to the stacking of sheets; a conveying section that conveys a sheet toward the stacking tray; a first acting portion and a second acting portion acting on both ends of the sheet stack in a width direction to align the sheet stack stacked on the stacking tray; an allowance portion that allows a next sheet to be temporarily received above the stack tray when the first action portion and the second action portion are aligning the sheet stack; An image forming system comprising:

Images