Sheet loading device and image forming system

Abstract

The present invention provides a sheet loading device and an image forming system that can align the next sheet to be loaded while suppressing disruption to the alignment of sheets already loaded on the first tray 49. [Solution] In the shift discharge mode, when moving the pair of alignment plates 401 and 402 in the shift direction to align the second and subsequent sheet bundles with the pair of alignment plates 401 and 402 and lowering them from the retracted position to the alignment-possible position, at least the alignment plate 401 located on the upstream side in the shift direction of the pair of alignment plates 401 and 402 is temporarily stopped from descending from the retracted position to the alignment-possible position before it contacts the upper surface of the first bundle of already loaded sheets SU placed on the first tray 49, and then lowered again to contact the upper surface of the already loaded sheets SU.

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 a pair of alignment parts that perform alignment in the width direction of sheets discharged onto the loading tray on the loading tray. In the case of the configuration described in Patent Document 1, the pair of alignment parts are movable to an alignment possible position where they descend to align the sheets on the loading tray in the shift discharge mode, and a retracted position where they retract upward so as not to interfere with the sheets to be shifted and discharged next.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the shift discharge mode, the sheets are shifted and discharged to one side in the width direction (here, the front side) to form a first sheet bundle on the loading tray, and then the sheets are shifted and discharged to the other side in the width direction (here, the rear side) to form a second sheet bundle at a position shifted to the rear side and above the first sheet bundle. At that time, the pair of alignment parts descend to the alignment possible position in a state of moving to the front side when forming the first sheet bundle, and then align the sheets shifted and discharged to the front side. Then, after aligning the last sheet of the first sheet bundle, the pair of alignment parts rise to the retracted position, descend to the alignment possible position in a state of moving to the rear side, and then align the first sheet of the second sheet bundle shifted and discharged to the rear side.

[0005] Here, in order to align the sheets of the second sheet bundle, the pair of aligning parts are moved to the rear and lowered from the retracted position to the aligning position. The rear aligning part descends to a section without a sheet, while the front aligning part rests on the top sheet of the first sheet bundle, which is already loaded on the loading tray. In this state, the pair of aligning parts align the sheets of the second sheet bundle.

[0006] In this configuration, if the pair of alignment parts are moved all at once from the retracted position to the alignment-possible position, when aligning sheets from the second sheet bundle onward in shift discharge mode, one of the alignment plates may forcefully strike the upper surface of the top sheet of the sheet bundle loaded on the loading tray, potentially causing the sheet to shift.

[0007] The present invention aims to provide a sheet loading device and an image forming system that can align the next sheet to be loaded while suppressing disruption to the alignment of sheets already loaded on the loading tray. [Means for solving the problem]

[0008] One aspect of the present invention comprises a conveying unit for conveying sheets in a conveying direction, a shifting unit for shifting the sheets conveyed by the conveying unit in a sheet width direction intersecting the conveying direction, a loading tray for stacking sheets, a discharge unit for discharging sheets toward the loading tray, a first alignment unit and a second alignment unit that act on both ends in the width direction of the sheet bundle loaded on the loading tray to align the sheet bundle, a retracted position where the first alignment unit and the second alignment unit are retracted above the sheets shifted by the shifting unit and discharged by the discharge unit, a lifting mechanism for raising and lowering the first alignment unit and the second alignment unit to an alignment-possible position where the sheets discharged toward the loading tray can be aligned, a moving mechanism for moving the first alignment unit and the second alignment unit in the sheet width direction, and the lifting mechanism and the moving mechanism The sheet loading device comprises a control unit that controls the shift unit, and in a shift discharge mode in which sheets are shifted onto the loading tray by the shift unit and discharged, the control unit moves the first and second alignment units in the shift direction in order to align the second and subsequent sheet bundles with the first and second alignment units, and when lowering them from the retracted position to the alignment-possible position, the control unit is characterized in that, of the first and second alignment units, at least the alignment unit located on the upstream side in the shift direction is temporarily stopped from descending from the retracted position to the alignment-possible position before the alignment unit contacts the upper surface of the first bundle of already loaded sheets loaded on the loading tray, and then lowers again to contact the upper surface of the already loaded sheets.

[0009] One aspect of the present invention includes an image forming unit for forming an image on a sheet, a transport unit for transporting the sheet on which the image has been formed in the image forming unit in a transport direction, a shift unit for shifting the sheet transported by the transport unit in a sheet width direction intersecting the transport direction, a loading tray for loading sheets, a discharge unit for discharging sheets toward the loading tray, a first alignment unit and a second alignment unit that act on both ends in the width direction of the sheet bundle loaded on the loading tray to align the sheet bundle, a retraction position where the first alignment unit and the second alignment unit are retracted above the sheet that is shifted by the shift unit and discharged by the discharge unit, and a lifting mechanism for raising and lowering the first alignment unit and the second alignment unit to an alignment-possible position where the sheet discharged toward the loading tray can be aligned, and a moving machine for moving the first alignment unit and the second alignment unit in the sheet width direction. The image forming system comprises a structure and a control unit that controls the lifting mechanism and the moving mechanism, wherein in a shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and when lowering them from the retracted position to the alignment-possible position, the control unit is characterized in that, of the first and second alignment units, at least the alignment unit located on the upstream side in the shift direction is temporarily stopped from descending from the retracted position to the alignment-possible position before the alignment unit contacts the upper surface of the first bundle of already loaded sheets on the loading tray, and then lowers again to contact the upper surface of the already loaded sheets.

[0010] One aspect of the present invention comprises: a conveying unit for conveying sheets in a conveying direction; a shifting unit for shifting sheets conveyed by the conveying unit in a sheet width direction intersecting the conveying direction; a loading tray for stacking sheets; a discharge unit for discharging sheets toward the loading tray; a first alignment unit and a second alignment unit that act on both widthwise edges of the sheet bundles stacked on the loading tray to align the sheet bundles; a retracted position where the first alignment unit and the second alignment unit are retracted above the sheets shifted by the shifting unit and discharged by the discharge unit; a lifting mechanism for raising and lowering the first alignment unit and the second alignment unit to an alignment-possible position where the sheets discharged toward the loading tray can be aligned; a moving mechanism for moving the first alignment unit and the second alignment unit in the sheet width direction; and a control unit for controlling the lifting mechanism and the moving mechanism. In a shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and when lowering them from the retracted position to the alignment-possible position, the control unit is characterized in that, of the first and second alignment units, at least the alignment unit located on the upstream side in the shift direction is decelerated from a first speed to a second speed before the alignment unit contacts the upper surface of the first bundle of already loaded sheets on the loading tray while lowering from the retracted position to the alignment-possible position, and then lowered again at a third speed slower than the first speed to contact the upper surface of the already loaded sheets.

[0011] One aspect of the present invention includes an image forming unit for forming an image on a sheet, a transport unit for transporting the sheet on which the image has been formed in the image forming unit in a transport direction, a shift unit for shifting the sheet transported by the transport unit in a sheet width direction intersecting the transport direction, a loading tray for loading sheets, a discharge unit for discharging sheets toward the loading tray, a first alignment unit and a second alignment unit that act on both ends in the width direction of the sheet bundle loaded on the loading tray to align the sheet bundle, a lifting mechanism for raising and lowering the first alignment unit and the second alignment unit to a retracted position above the sheet that is shifted by the shift unit and discharged by the discharge unit, and to an alignment-possible position for aligning the sheet that has been discharged toward the loading tray, a moving mechanism for moving the first alignment unit and the second alignment unit in the sheet width direction, and a control for the lifting mechanism and the moving mechanism. The image forming system comprises a control unit and, in a shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and when lowering them from the retracted position to the alignment-possible position, the control unit is characterized in that, of the first and second alignment units, at least the alignment unit located on the upstream side in the shift direction is decelerated from a first speed to a second speed before the alignment unit contacts the upper surface of the first bundle of already loaded sheets on the loading tray while lowering from the retracted position to the alignment-possible position, and then lowered again at a third speed that is slower than the first speed and faster than the second speed, thereby contacting the upper surface of the already loaded sheets. [Effects of the Invention]

[0012] According to the present invention, it is possible to ensure alignment of the next sheet to be loaded while suppressing disruption of the alignment of sheets already loaded on the loading tray. [Brief explanation of the drawing]

[0013] [Figure 1] A schematic cross-sectional view of the image forming system according to the first embodiment. [Figure 2]A schematic cross-sectional view of the sheet processing apparatus according to the first embodiment. [Figure 3] A control block diagram of an image forming system according to the first embodiment. [Figure 4] An enlarged cross-sectional view of a part of the sheet processing apparatus according to the first embodiment. [Figure 5] A control block diagram of a sheet processing apparatus according to the first embodiment. [Figure 6] A cross-sectional view showing a portion of the sheet processing apparatus according to the first embodiment, from the first transport roller to the first tray. [Figure 7] A top view showing a portion of the sheet processing apparatus according to the first embodiment, from the first transport roller to the first tray. [Figure 8] A perspective view of the area around the alignment plate according to the first embodiment, showing the alignment plate in the home position. [Figure 9] This is a perspective view of the area around the alignment plate according to the first embodiment, showing the alignment plate in a state where it has been lowered from the home position. [Figure 10] Figure 8 is a perspective view with the matching plate and paddle's HP sensors added. [Figure 11] Figure 9 is a perspective view with the matching plate and paddle's HP sensors added. [Figure 12] This is a perspective view showing the interlocking mechanism according to the first embodiment, with the alignment plate in the home position. [Figure 13] This is a perspective view showing the interlocking mechanism according to the first embodiment, with the alignment plate in a lowered position from the home position. [Figure 14] (a) Cross-sectional view, (b) Top view, showing a portion of the sheet processing device from the first transport roller to the first tray in the shift discharge mode according to the first embodiment, when the first sheet is detected by the register detection sensor. [Figure 15] (a) Cross-sectional view, (b) Top view, showing a portion of the sheet processing device from the first transport roller to the first tray in the shift discharge mode according to the first embodiment, with the first sheet shifted to the front side. [Figure 16] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the first sheet is discharged to the first tray. [Figure 17] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the second sheet is being discharged to the first tray during alignment of the first sheet. [Figure 18] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the second sheet is being aligned. [Figure 19] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the first sheet of the second sheet bundle is being buffered during alignment of the last sheet of the first sheet bundle. [Figure 20] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the first and second sheets of the second sheet bundle are being discharged. [Figure 21] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the first and second sheets of the second sheet bundle are being aligned. [Figure 22] In the shift discharge mode according to the first embodiment, (a) cross-sectional view and (b) top view showing a part from the first conveyance roller to the first tray of the sheet processing apparatus in a state where the third sheet is being discharged to the first tray during alignment of the first and second sheets of the second sheet bundle. [Figure 23](a) Perspective view showing the sheet bundle being discharged straight onto the first tray, (b) Perspective view showing the sheet bundle being discharged in a shifted manner onto the first tray. [Figure 24] A cross-sectional view of the first tray and the area around the alignment plate, showing the alignment plate being rapidly lowered from the retracted position to the alignment-possible position. [Figure 25] A cross-sectional view of the first tray and the area around the alignment plate, showing the alignment plate according to the first embodiment in a position where alignment is possible. [Figure 26] A cross-sectional view of the first tray and the area around the alignment plate, showing the alignment plate in the retracted position according to the first embodiment. [Figure 27] A cross-sectional view of the first tray and the area around the alignment plate, showing the state in which the alignment plate according to the first embodiment has temporarily stopped while descending from the retracted position to the alignment-possible position. [Figure 28] (a) A cross-sectional view of the first tray and the area around the alignment plate showing the alignment plate according to the first embodiment in a state where it has stopped and then descended to an alignment position, and (b) an enlarged view of a part of (a). [Figure 29] A cross-sectional view of the first tray and the area around the alignment plate according to the second embodiment, showing (a) the state in the retracted position, (b) the state in which it has temporarily stopped while descending from the retracted position to the alignment-possible position, and (c) the state in which it has descended to the alignment-possible position after temporarily stopping. [Modes for carrying out the invention]

[0014] <First Embodiment> The first embodiment will be described using Figures 1 to 28(b). First, the schematic configuration of the image forming system of this embodiment will be described using Figure 1.

[0015] [Image Forming System] In this embodiment, a copier is used as the image forming apparatus, and a sheet processing apparatus is connected to the opening of the sheet of the copier. The image forming system 1000 is composed of an image forming apparatus A and a sheet processing apparatus B. The sheet S, which has an image formed by the image forming apparatus A, is received by the downstream sheet processing apparatus B, which performs predetermined processing such as binding as necessary, and then sends it to the downstream output unit. The image forming apparatus A includes various structures such as copiers, printers, printing presses, facsimile machines, and multifunction devices having multiple functions of these. The image forming apparatus A and the sheet processing apparatus B will be described in detail below. In the following description, the side on which the user or other operator operates the device (for example, the side with the operation panel and operation buttons) is referred to as the front side (the front side of the paper in Figures 1 and 2, etc.), and the side opposite the front side is referred to as the rear side (the back side of the paper in Figures 1 and 2, etc.).

[0016] [Image forming apparatus] As shown in Figure 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, housed in the apparatus housing 1, comprises a feeding unit 2, an image forming unit 3, an output unit 4, and a data processing unit 5.

[0017] The feeding unit 2 includes multiple cassettes 2a, 2b, and 2c, each capable of storing sheets S of different pre-selected standard sizes. The sheets S are, for example, paper or plastic sheets. Each cassette 2a, 2b, and 2c has a built-in separation mechanism for separating the sheets S one by one and a feeding mechanism for feeding the sheets S. The sheets S stored in the feeding unit 2 with this configuration are fed into the feeding path 6 by the control unit 310 (Figure 3) of the image forming apparatus A, according to the size of the sheet S specified. The feeding path 6 is equipped with transport rollers 7 for transporting the sheets S supplied from the multiple cassettes 2a, 2b, and 2c to the downstream side, and a pair of registration rollers 8 positioned at the end of the path to align the leading edge of each sheet S. The sheets S aligned by the registration roller pair 8 are fed to the downstream image forming unit 3 at a predetermined timing.

[0018] The feed path 6 is connected to a high-capacity cassette 2d and a manual feed tray 2e. The high-capacity cassette 2d consists of an optional unit that stores sheets of sizes consumed in large quantities. The manual feed tray 2e is configured to supply special sheets such as cardboard sheets, coated sheets, and film sheets that are difficult to feed separately.

[0019] The image forming unit 3 only needs to be configured to form an image on the sheet S sent from the feeding unit 2, and various image forming mechanisms can be employed. 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 an inkjet image forming mechanism, an offset image forming mechanism, etc., can also be employed.

[0020] The image forming unit 3 shown in Figure 1 is equipped with a photoreceptor 9 formed in the shape of a drum or belt, and a light emitter 10 that emits an optical beam onto the photoreceptor 9. A developer 11 and a cleaner (not shown) are arranged around the rotating photoreceptor 9. The illustrated mechanism is a monochrome printing mechanism, in which a latent image is optically formed on the photoreceptor 9 by the light emitter 10, and toner is applied to this latent image by the developer 11. The toner image applied to the photoreceptor 9 is transferred to a sheet S sent from the feeding unit 2 by the transfer charger 12, and after the image transferred to the sheet S is fixed by the fixing roller 13, it is sent to the transport path 14. In addition, the image forming unit 3 is provided with a circulation path below the transport path 14, and after the sheet S from the transport path 14 is flipped over by the switchback path, it is sent again to the registration roller pair 8, where an image is formed on the back side of the sheet S, and then sent to the transport path 14. A discharge roller 15 (a so-called discharge roller) is positioned in the transport path 14, and an opening 16 is formed at its end. The discharge roller 15 sends the sheet S from the opening 16 to the sheet processing device B, which will be described later.

[0021] An image reading unit A2, which optically reads the original image to be formed by the image forming unit 3, is provided at the top of the image forming unit A1 configured in this way, and a document feeding unit A3 is mounted even higher up on the image reading unit A2.

[0022] The image reading unit A2 comprises a first platen 17 and a second platen 21 made 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 composed of a combination of mirrors and lenses. The reading carriage 18 is scanned along the first platen 17 to illuminate the image of the document placed on the first platen 17 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.

[0023] The document feeding unit A3 comprises a feeding tray 22, a feeding path 23, and a stacking tray 24. Documents placed on the feeding tray 22 are transported one by one along the feeding path 23, passing over the second platen 21, and sent to the stacking tray 24. When scanning documents fed from the document feeding unit A3 and passing over the second platen 21, the scanning carriage 18 is stopped in advance below the second platen 21, and image data is generated from the images passing over the second platen 21.

[0024] [Overall configuration of the sheet processing device] Next, the overall configuration of the sheet processing device B, which performs processing such as stapling and folding on sheets sent from the image forming apparatus A, will be explained using Figure 2. Figure 2 shows the detailed configuration of the sheet processing device B. After processing the sheets received by the sheet processing device B from the receiving section 26, which is the entrance to the straight path 28 connected to the opening 16 of the image forming apparatus A, the sheets can be loaded onto the first tray (first loading tray) 49, the saddle loading unit 131, and the second tray (second loading tray) 71, which will be described later. The part of the sheet processing device B other than the first tray 49 and the second tray 71 is called the processing unit 200. That is, the processing unit 200 includes the apparatus housing 27, the straight path 28, the processing unit B1, and the saddle section B2, which will be described later.

[0025] In the illustrated apparatus, sheets sent to the transport path and the straight path 28, which is the first transport path, are transferred from the processing unit B1 (described later) to the first tray 49 and the second tray 71, and from the saddle section B2 (described later) to the saddle loading unit 131. Each of these devices has a control unit, a communication unit, etc., as shown in the block diagram illustrating the control configuration of the entire apparatus in Figure 3, and controls the apparatus through these components.

[0026] The processing unit B1 is positioned below the exit point (transfer section 35) of the straight path 28. It aligns and stacks multiple sheets sequentially transferred from the straight path 28 via the transfer section 35 to form a sheet bundle, and can perform a binding process, which is an example of a predetermined process, on the ends of this sheet bundle. The bound sheet bundle is then loaded onto the first tray 49, which serves as a loading section.

[0027] Saddle section B2 is located below the transfer section of the saddle path 32, which is a second transport path branching vertically downward from the straight path 28. Multiple sheets that are sequentially transferred from the straight path 28 via the saddle path 32 and the transfer section are aligned and stacked to form a sheet bundle, which is then saddle-stitched, or folded without saddle-stitching, and sent to the saddle loading unit 131. Each component will be described in detail below.

[0028] [Device Housing] As shown in Figure 2, the sheet processing apparatus B comprises an apparatus housing 27, a straight path 28, a processing unit B1, a saddle section 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, processing unit B1, and saddle section B2 are located inside the apparatus housing 27. The straight path 28 also has a sheet receiving section 26 and a sheet transfer section 35. The processing unit B1 and saddle section B2 process the sheets transferred from the transfer section 35 of the straight path 28. The first tray 49, saddle loading unit 131, and second tray 71 load the sheets sent from each processing unit. The illustrated apparatus housing 27 is connected to the apparatus housing 1 of the image forming apparatus A, which is located upstream in the sheet transport direction of the straight path 28. The device housing 27 and the device housing 1 are positioned such that the height from the installation surface of the opening 16 of the image forming apparatus A and the receiving section 26 of the sheet processing apparatus B are approximately the same, and the opening 16 and the receiving section 26 are connected.

[0029] [Sheet acceptance route] As shown in Figures 2 and 4, the straight path 28, which is the sheet receiving path, is a substantially straight path that crosses the device housing 27 in a substantially horizontal direction and includes a receiving section 26 connected to the opening (main body opening) 16 of the image forming apparatus A, and a transfer section 35 located on the opposite side across the device from the receiving section 26. The straight path 28 is equipped with an inlet roller 29, a first conveying roller 201, a second conveying roller (shift roller) 202, and a third conveying roller (shift roller) 203, which are conveying rollers that can transport sheets in a first direction from the receiving section 26 toward the first discharge path 31, and also transport sheets in a second direction from the first discharge path 31 toward the receiving section 26. In other words, the inlet roller 29, the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203 can transport sheets in a first direction and in a second direction opposite to the first direction along the conveying path, and are arranged in order from the receiving section 26 side toward the first direction.

[0030] Furthermore, the second conveyor roller 202 and the third conveyor roller 203 are also shift rollers capable of moving the sheet in the width direction (front-rear direction) intersecting the sheet conveying direction. That is, the second conveyor roller 202 and the third conveyor roller 203 are movable in the width direction by a drive unit (not shown), and it is possible to shift the sheet to the front or rear side while gripping the sheet.

[0031] The first discharge path 31 is connected to the transfer section 35 of the straight path 28, and a pre-processing roller 36, which serves as a conveying section, is positioned at this connection section. Sheets are transferred from the straight path 28 to the first discharge path 31, and then sent out from the first discharge path 31, either to the first tray 49 or guided to the processing unit B1. Note that the aforementioned conveying rollers may be other components capable of conveying sheets, such as conveying belts.

[0032] [Layout of the sheet receiving route] As shown in Figures 2 and 4, the straight path 28 is connected to branch paths, the saddle path 32 and the upper transport path 30. The saddle path 32 and the upper transport path 30 are arranged sequentially from the receiving section 26 toward the first discharge path 31 in the first direction. The saddle path 32 branches off vertically downward from the straight path 28, and the upper transport path 30 branches off vertically upward from the straight path 28. At the branching points of the straight path 28 and the saddle path 32 and upper transport path 30, respectively, a saddle path switching member 33 and an upper transport path switching member 34 are provided to switch the transport direction of the transported sheets.

[0033] Furthermore, a buffer path 39, which is a branch path that branches vertically downward from the straight path 28, is connected between the second transport roller 202 and the third transport roller 203. The buffer path 39, acting as a buffer section, is a path that can temporarily hold the sheet. When buffering a sheet in the buffer path 39, the sheet that has been transported downstream of the branch point of the buffer path 39 on the straight path 28 is transported in the opposite direction to the first direction by reversing the rotation of the third transport roller 203, etc., and guided to the buffer path 39 by a switching member (not shown).

[0034] Then, the sheet is transported to the buffer path 39 by the transport roller 208, and the rotation of the transport roller 208 is stopped when the rear end of the sheet has exited the straight path 28. In this state, the next sheet can be transported in the straight path 28 to the first downstream side of the branching point of the buffer path 39. In addition, in this embodiment, by rotating the transport roller 208 in the reverse direction, the sheet in the buffer path 39 can be transported toward the straight path 28, and this sheet and the next sheet can be merged at the branching point. Furthermore, these two sheets can also be stacked and transported by the third transport roller 203 and the pre-processing roller 36, which act as a buffer transport section.

[0035] [Path branching] The upper transport path switching member 34 consists of a switching member guide that moves to change the transport path so that the sheet received from the receiving section 26 is transported to either the first discharge path 31 or the upper transport path 30, and is connected to a drive unit (not shown) such as an electromagnetic solenoid or a mini motor.

[0036] [Upper transport path] The straight path 28 is connected to an upper transport path 30 (printout transport path) that transports sheets other than those to be transported to the first transport path 31, and the path branching section is equipped with an upper transport path switching member 34 for guiding sheets to the upper transport path 30. The upper transport path 30 is also equipped with a fourth transport roller 204, a fifth transport roller 205, a sixth transport roller 206 as transport rollers that guide sheets to the second tray 71, and a second discharge roller pair 207 as a discharge section. As a result, sheets guided to the upper transport path 30 are sent out from the upper transport path opening 40 to the second tray 71 (overflow tray) which serves as a loading tray (loading section) by the second discharge roller pair 207.

[0037] Processing unit B1 is located downstream of the straight path 28 and consists of a processing tray 37 as a loading section for placing sheets sent from the first discharge path 31 and aligning and accumulating multiple sheets, and a stapling mechanism (stapler) 47 as a processing section for stapling the accumulated sheet bundles. Processing unit B1 then performs stapling on the sheet bundles placed on the processing tray 37. The stapling mechanism 47 is located vertically below the straight path 28. The stapling mechanism 47 is movable in the width direction and can perform stapling at a desired position in the width direction on the sheet bundles placed on the processing tray 37. As shown in Figures 2 and 4, the processing tray 37 is located below the first discharge path 31, forming a step. Between the first discharge path 31 and the processing tray 37, a first switchback path is formed that reverses the transport direction from the opening 31a of the first discharge path 31 and guides the sheets onto the processing tray 37.

[0038] Specifically, the first discharge path 31 is provided with an upper conveyor roller 41 and a lower conveyor roller 48 that grip and transport the sheets. The upper conveyor roller 41 and the lower conveyor roller 48 constitute a discharge roller pair 42 as a discharge section. The upper conveyor roller 41 can come into contact with and separate from the lower conveyor roller 48, and the upper conveyor roller 41 and the lower conveyor roller 48 can transport the sheets toward the first tray 49 (discharge direction) and in the opposite direction while gripping the sheets. The upper conveyor roller 41 and the lower conveyor roller 48 can then transport the sheets toward the processing tray 37 via the first switchback path. The upper conveyor roller 41 and the lower conveyor roller 48 (i.e., the discharge roller pair 42) also send the sheets or bundles of sheets on the processing tray 37 from the opening 31a to the first tray 49, which serves as a loading tray (loading section). The opening 31a is a portion of the device housing 27 that opens above the lower conveyor roller 48. Furthermore, the discharge roller pair 42 sends the sheets that have been transported to the first discharge path 31 without passing through the processing tray 37 to the first tray 49 through the opening 31a.

[0039] The processing unit B1 has a rear end restricting section 47a, which acts as a stopper to position the sheet by contacting the end (rear end) of the sheet. On the processing tray 37, there is a scraping section 38 that transports the sheets conveyed to the processing tray 37 by the upper transport roller 41 and the lower transport roller 48 toward the rear end restricting section 47a. The binding processing mechanism 47 is placed on the processing tray 37 and performs binding on the ends of a sheet bundle consisting of multiple sheets whose end positions are restricted by the rear end restricting section 47a. The binding processing mechanism 47 also has a sheet bundle discharge mechanism that discharges the sheet bundle to the first tray 49 after performing binding on the ends of the sheet bundle.

[0040] The processing unit B1 also includes a pair of alignment plates 270 as a shift section, a rear end drop member 44 as a sheet drop section, and a bundle release member 45. The pair of alignment plates 270 move in the width direction of the sheet (shift direction) intersecting the first direction while in contact with the edge of the sheet placed on the processing tray 37 along the transport direction (first direction), thereby moving the sheet transported by the pre-processing roller 36 in the width direction. The pair of alignment plates 270 are arranged to face each other in the width direction. The pair of alignment plates 270 also move in the width direction and contact the width direction edge of the sheet to align the sheet in the width direction. The front alignment plate 270 of the pair of alignment plates 270 is moved in the width direction by the alignment plate 1 move motor M13, and the rear alignment plate 270 is moved in the width direction by the alignment plate 2 move motor MT14.

[0041] The rear end drop member 44 is positioned above the processing tray 37 and moves vertically to contact the upper surface on the upstream side in the conveying direction of the sheet, causing the upstream end (rear end) of the sheet to drop towards the processing tray 37. The bundle discharge member 45 pushes the rear end of the sheet bundle placed on the processing tray 37, thereby discharging the sheet bundle into the first tray 49.

[0042] Furthermore, the binding unit B1 shown in Figure 2 supports the sheets sent from the first discharge path 31 so that they straddle the processing tray 37 and the first tray 49 downstream of it. In other words, the leading edge of the sheet sent from the first discharge path 31 is supported on the uppermost sheet of the first tray 49 downstream, and the trailing edge is supported on the processing tray 37.

[0043] [Saddle Pass] A saddle path 32 for transporting sheets to the saddle section B2 is connected to the straight path 28, and a saddle path switching member 33 for guiding sheets to the saddle path 32 is provided at the path branching section. Sheets guided to the saddle section B2 by the saddle path 32 undergo a folding process, and after folding, are sent to the saddle loading unit 131 via a substantially horizontal post-fold path guide 114, a second roller post-path guide 116, and a saddle discharge guide 124. In this embodiment, the saddle discharge guide 124 is used as an auxiliary guide to ensure that sheets are properly loaded into the saddle loading unit 131.

[0044] [Control Configuration] Using Figure 3, the control configuration of the image forming system 1000 will be outlined. First, the image forming apparatus A has a control unit 310, an operation unit 302, a transport control unit 303, an image processing unit 304, a drive unit 305, and a communication unit 306. The control unit 310 has a CPU (Central Processing Unit) 311, a ROM (Read Only Memory) 312, and a RAM (Random Access Memory) 313. The CPU 311 controls each part while reading programs corresponding to control procedures stored in the ROM 312. In addition, the RAM 313 stores work data and input data, and the CPU 311 controls by referring to the data stored in the RAM 313 based on the aforementioned programs, etc.

[0045] The operation unit 302 is connected to the control unit 310 and is, for example, an operation panel provided on the image forming apparatus A, allowing the operator to operate the apparatus and make various settings. The transport control unit 303 controls the various transport rollers and switching members that switch transport paths for transporting sheets 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 connects the control unit 310 to external devices 301 such as a personal computer and the communication unit 321 of the sheet processing apparatus B so that they can communicate with each other.

[0046] The sheet processing apparatus B includes a stacker control unit 330, a transport control unit 322, an edge binding control unit 323, an discharge processing control unit 324, and a communication unit 321. The stacker control unit 330, like the control unit 310, includes a CPU 331, a ROM 332, and a RAM 333. The transport control unit 322 controls various transport rollers and switching members that switch transport paths for transporting sheets in areas other than the saddle section B2 of the sheet processing apparatus B. The edge binding control unit 323 controls the processing unit B1. The discharge processing control unit 324 controls the discharge of sheets and various loading trays on which the discharged sheets are stacked. The communication unit 321 connects the stacker control unit 330 to the communication unit 306 of the image forming apparatus A and the communication unit 341 of the saddle section B2 so that they can communicate with each other. Communication between the communication unit 306 and the communication unit 321 may be performed by wired communication or wireless communication.

[0047] Furthermore, the communication unit 321 functions as a notification unit, and as will be described later, when it detects that a sheet is present on a loading tray such as the first tray 49 or the second tray 71, it notifies that a sheet is present. Specifically, it transmits information that a sheet is present to the communication unit 306 of the image forming apparatus A, causing, for example, the display unit of the operation unit 302 to display that a sheet is present.

[0048] The saddle unit B2 includes a saddle control unit 350, a transport control unit 342, a saddle stitching control unit 343, a center folding control unit 344, and a communication unit 341. The saddle control unit 350, like the control unit 310, includes a CPU 351, a ROM 352, and a RAM 353. The transport control unit 342 controls the various transport rollers and switching members that switch transport paths for transporting sheets in the saddle unit B2. The saddle stitching control unit 343 controls the saddle stitching processing unit 104. The center folding control unit 344 controls the center folding processing mechanism C1. The communication unit 341 connects the communication unit 321 of the sheet processing device B and the saddle control unit 350 to enable communication.

[0049] [Saddle section] As shown in Figure 2, the saddle section B2 has a center-folding mechanism C1. The center-folding mechanism C1 aligns and stacks the sheets sent from the straight path 28 to form a sheet bundle, performs a binding process on the center of the sheets and bundle in the direction of transport, and performs a center-folding process by folding the sheet bundle at the bound position. Downstream of the center-folding mechanism C1, a saddle loading unit 131 is positioned to store the bound sheet bundles. It is also possible to align and stack one or more sheets and perform only a center-folding process by folding the center in the direction of transport without performing a binding process.

[0050] [Sheet loading device] Details of the sheet loading device 400 of the sheet processing device B of this embodiment will be explained with reference to Figures 5 to 13. The sheet loading device 400 loads sheets that have undergone a predetermined process (in this embodiment, a binding process) by a binding processing mechanism 47 as a processing unit, or sheets that have not undergone a predetermined process. The sheet loading device 400 includes a pair of discharge rollers 42 (upper conveying roller 41 and lower conveying roller 48) as a conveying 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 alignment unit and a second alignment unit, and a jogger 1 moving motor MT20 and a jogger 2 moving motor MT21 as alignment member moving units.

[0051] The tray lifting motor MT18 (Figure 5) raises and lowers the first tray 49. The alignment plate 401 as the first working part and the alignment plate 402 as the second working part act on both 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 with the discharge direction (conveying direction) of the sheet by the pair of conveying rollers, the upper conveying roller 41 and the lower conveying roller 48, with respect to the top sheet loaded on the first tray 49, and align the top sheet in the width direction. 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 this embodiment, the pair of alignment plates 401 and 402 can each be moved independently in the width direction.

[0052] Here, the relationship between the drive motors and various sensors of a part of the sheet processing device B surrounding the sheet stacking device 400 will be explained using the block diagram in Figure 5. The various motors are controlled by the stacker control unit 330, which acts as a control unit, and the signals from the various sensors are sent to the stacker control unit 330. The stacker control unit 330 controls the drive of the various motors based on the signals from the various sensors.

[0053] First, the inlet conveyor motor MT1 rotates the inlet roller 29, the conveyor motor MT2 rotates the first conveyor roller 201, the shift 1 conveyor motor MT3 rotates the second conveyor roller (shift roller) 202, the shift 2 conveyor motor MT4 rotates the third conveyor roller (shift roller) 203, and the pre-processing conveyor motor MT5 rotates the pre-processing roller 36, each of these motors capable of rotating in both forward and reverse directions. Additionally, the discharge roller 1 motor MT6 rotates the upper conveyor roller 41 in both forward and reverse directions. The discharge roller 1 motor MT6 also rotates the paddle 275, which will be described later. The discharge roller 2 motor MT7 rotates the lower conveyor roller 48 in both forward and reverse directions. The buffer conveyor motor MT8 rotates the conveyor roller 208 that conveys the sheet in the buffer path 39 described above in both forward and reverse directions.

[0054] Furthermore, the shift 1 motor MT9 moves the second conveyor roller 202 in the width direction, and the shift 2 motor MT10 moves the third conveyor roller 203 in the width direction. The discharge roller oscillating motor MT11, as described above, is a motor that oscillates the upper conveyor roller 41 in the vertical direction so that it can come into contact with and separate from the lower conveyor roller 48. The rear end drop drive motor MT12 is a motor that moves the rear end drop member 44 in the vertical direction. The alignment plate 1 moving motor M13 and the alignment plate 2 moving motor MT14, as described above, are motors that move a pair of alignment plates 270 that align the sheets in the processing tray 37 in the width direction.

[0055] Furthermore, the stapler moving motor MT15 can move the stapling mechanism 47 in the width direction. The stapler motor MT16 is a motor that drives the stapling mechanism 47 to perform stapling. The bundle release motor MT17 is a motor that drives the bundle release member 45. The tray lifting motor MT18 is a motor that lifts and lowers the first tray 49. The jogger lifting motor MT19 is a motor that lifts and lowers a pair of alignment plates (joggers) 401 and 402 as described later. In this embodiment, the alignment plates 401 and 402 are lifted and lowered by one motor, but the alignment plates 401 and 402 may be lifted and lowered by separate motors. The jogger 1 moving motor MT20 and the jogger 2 moving motor MT21 move the pair of alignment plates 401 and 402 in the width direction, respectively, as described above. The paddle lifting motor MT22 is a motor that lifts and lowers the paddle 275, which will be described later.

[0056] Next, the various sensors will be described. As shown in Figure 4, the inlet sensor SN1 is provided at the inlet of the straight path 28 and detects the sheet that has been passed to the sheet processing device B from a device connected to the upstream side of the sheet processing device B (in this embodiment, the image forming device A). As shown in Figures 6 and 7, the register detection sensor SN2 is positioned on the upstream side in the transport direction of the second transport roller 202, which is a shift roller, and detects the position of the sheet in the width direction. As shown in Figure 4, the sheet edge detection sensor SN3 is positioned on the upstream side in the transport 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 the discharge roller pair 42 after a predetermined time has elapsed since the rear end of the sheet passed the sheet edge detection sensor SN3.

[0057] The shift roller 1HP detection sensor SN4 detects the home position (HP) of the second transport roller 202 in the width direction. The shift roller 2HP detection sensor SN5 detects the home position (HP) of the third transport roller 203 in the width direction. The jogger lifting HP detection sensor SN6 detects the home position (HP) of the pair of alignment plates 401 and 402 in the lifting direction. The jogger 1HP detection sensor SN7 detects the home position (HP) of the front alignment plate 401 in the width direction. The jogger 2HP detection sensor SN8 detects the home position (HP) of the rear alignment plate 402 in the width direction. The pair of alignment plates 401 and 402 are movable in the width direction, as will be described later. The home positions of the pair of alignment plates 401 and 402 in the lifting direction and in the width direction are the positions shown in Figures 6 and 7.

[0058] 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 Figures 6 and 7. The sheet top surface detection sensor SN10 detects the top surface of the sheet on the first tray 49. In this embodiment, the sheet top 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 that detects when a sheet bundle, which is stacked on the first tray 49, is suddenly removed while the first tray 49 is lowered.

[0059] Next, the configuration of the sheet processing device B from the first conveyor roller 201 to the first tray 49 will be described using Figures 6 and 7. Figures 6 and 7 are cross-sectional and top views, respectively, of the pair of alignment plates 401, 402 and paddle 275 in their home positions. The configuration from the first conveyor roller 201 to the discharge roller pair 42 is as described above, so the sheet loading device 400, which is the configuration around the first tray 49, will be described below.

[0060] The first tray 49 loads the sheets discharged from the opening 31a of the first discharge path 31. On the outer surface of the device housing 27, below the opening 31a, a stopper member 271 is provided between the first tray 49 and the processing unit B1, against which the rear end (the upstream end with respect to the discharge direction) of the discharged sheet abuts. This stopper member 271 serves to align the transport direction of the sheets discharged and loaded onto the first tray 49. The loading surface 49a, which is the upper surface of the first tray 49, slopes gently downward toward the stopper member 271. That is, the loading surface 49a on which the sheets of the first tray 49 are loaded is inclined at a first angle with respect to the horizontal direction, so that it slopes upward toward the downstream side in the discharge direction. After the sheets discharged from the opening 31a onto the loading surface 49a fall onto the first tray 49, they slide down along the slope of the loading surface 49a, and eventually the rear end of the sheet reaches the stopper member 271 and stops.

[0061] The first tray 49 moves up and down via a lifting mechanism (not shown) by a tray lifting motor MT18. That is, when discharging sheets onto the first tray 49 or the second tray 71, it is necessary to raise and lower the first tray 49 or the second tray 71 in order to maintain a constant position on the loading surface 49a or the topmost sheet on the loading surface 49a so as not to reduce the alignment of the loaded sheets. For this purpose, in this embodiment, the tray lifting motor MT18, which acts as a lowering unit, lowers the first tray 49 or the second tray 71 in accordance with the loading of sheets so that the height of the topmost sheet of the sheets discharged by the discharge roller pair 42 or the second discharge roller pair 207 and loaded onto the first tray 49 or the second tray 71 is within a predetermined range, and raises the first tray 49 or the second tray 71 once the sheets loaded on the first tray 49 or the second tray 71 have been removed.

[0062] Furthermore, above the first tray 49, a pair of alignment plates 401 and 402 are positioned to align the sheets in the width direction intersecting the sheet discharge direction, and a paddle 275 is positioned to align the sheets in the discharge direction. The pair of alignment plates 401 and 402 are movable in the vertical direction and in the width direction. That is, the pair of alignment plates 401 and 402 are movable up and down by a jogger lifting motor MT19, which serves as the alignment member lifting unit, to a first position (alignable position) where the uppermost sheet on the first tray 49 can be aligned, and a second position (retracted position) which is above the first position and retracted above the sheet discharged from the discharge roller pair 42 so as not to interfere with the discharged sheet. In addition, at least one of the pair of alignment plates 401 and 402 is movable to an alignment position that aligns the sheet bundle in the width direction, and to a position further from the widthwise edge of the sheet bundle than the alignment position. Specifically, the pair of alignment plates 401 and 402 are movable by the jogger 1 moving motor MT20 and the jogger 2 moving motor MT21, which serve as alignment member moving parts, to an alignment position where the uppermost sheet is aligned in the width direction, and to a position further away from the uppermost sheet in the width direction than the alignment position. The position further away from the uppermost sheet in the width direction than the alignment position is, for example, the sheet receiving position, which will be described later.

[0063] The loading surface 49a of the first tray 49 has a recess 49b into which a pair of alignment plates 401 and 402 can enter when they descend. Figures 6 and 7 show the state in which the pair of alignment plates 401 and 402 are retracted above the nip point N1 of the upper conveyor roller 41 and the lower conveyor roller 48, and in this state the sheet is discharged from the opening 31a. Once the sheet is discharged into the first tray 49, the pair of alignment plates 401 and 402 descend to a first position in which a portion enters the recess 49b, and move in the width direction from the sheet receiving position to the alignment position, striking both ends of the sheet in the width direction from both sides of the sheet. This aligns the sheet in the width direction.

[0064] On the other hand, the paddle 275 is movable vertically and can rotate to transport the sheet on the first tray 49 in the opposite direction to the discharge direction. That is, the paddle 275 can move to a transport position in which it contacts the sheet on the first tray 49 and transports the sheet upstream with respect to the sheet's discharge direction, and to an upper position which is retracted above the transport position. Figures 6 and 7 show the state in which the paddle 275 is retracted above the opening 31a (in the upper position), and in this state the sheet is discharged from the opening 31a. Once the sheet is discharged into the first tray 49, the paddle 275 descends toward the transport position and rotates, transporting the sheet discharged from the opening 31a toward the abutment member 271 while dropping it into the first tray 49.

[0065] [Matching board] Next, the configuration of the pair of alignment plates 401 and 402 will be described using Figures 8 and 9. The pair of alignment plates 401 and 402 are each supported so as to be able to swing vertically with respect to the pivot axis 405 via a pair of swing arms 403 and 404. The pair of swing arms 403 and 404 and the pivot axis 405 will be described later.

[0066] Figure 8 is a perspective view of the area around the pair of matching plates 401 and 402 when they are in their home position (second position), and Figure 9 is a perspective view of the area around the pair of matching plates 401 and 402 when they have been lowered from the second position to the first position. In the state shown in Figure 9, the pair of matching plates 401 and 402 have simply been lowered from the second position to the first position, but the orientation of the pair of matching plates 401 and 402, that is, the angle of the second imaginary line α2 (Figure 19(a)) with respect to the horizontal direction, is the same as the orientation at the matching position.

[0067] Each pair of alignment plates 401 and 402 has an alignment surface 4001 as an alignment section, a guide surface 4002 as an allowable section (guide section), and a sheet receiving surface 4003 as an inclined section (upstream guide section). The basic configuration of alignment plates 401 and 402 is the same, except that the alignment surfaces 4001 that perform sheet alignment are arranged opposite each other. Therefore, in the following description, alignment plate 401 will be given a reference numeral as a representative.

[0068] The alignment surface 4001 is a surface that contacts both edges in the width direction of the sheet bundle when the sheet bundle is aligned, and may be a flat surface or a surface with some irregularities. The alignment plates 401 and 402 each have a first portion 4001a downstream with respect to the sheet discharge direction by the discharge roller pair 42, and a second portion 4001b upstream of the first portion 4001a. The width (vertical length) of the first portion 4001a in the vertical direction is greater than the width of the second portion 4001b in the vertical direction. Also, the upper end of the first portion 4001a and the upper end of the second portion 4001b are located on the same straight line and are continuous with the guide surface 4002, which will be described later.

[0069] On the other hand, the lower end of the first portion 4001a is inclined such that a portion on the downstream side in the discharge direction slopes upward as it moves downstream, while the upstream side of this portion slopes upward as it moves upstream. The lower end of the second portion 4001b is continuous with the lower end of the upstream portion of the first portion 4001a and is further inclined with a larger angle than the upstream portion, so as it moves upward as it moves upstream in the discharge direction. This makes the vertical width of the first portion 4001a of the matching surface 4001 larger than the width of the second portion 4001b. This allows the first portion 4001a of the matching surface 4001 to contact or face the widthwise edge of the sheet on the first tray 49 over a wide area in the vertical direction. The recess 49b of the first tray 49 described above has a shape corresponding to the shape of the lower end of the matching plates 401 and 402 so that the lower ends of these plates can enter it.

[0070] The guide surface 4002 allows the temporary acceptance of the next sheet above the first tray 49 while the pair of alignment plates 401 and 402 are aligning the sheet bundle. Here, "while aligning the sheet bundle" refers to a series of operations in which the pair of alignment plates 401 and 402 move from the acceptance position to the alignment position and then back to the acceptance position. Furthermore, "temporary acceptance of the next sheet" means temporarily guiding the next sheet in the same job as the sheet bundle being aligned on the first tray 49, or the next sheet in a job that is consecutive to the job of this sheet bundle, above the first tray 49 until the alignment of the sheet bundle is complete. If "the next sheet" is the next sheet in the same job as the sheet bundle being aligned on the first tray 49, for example, in a job where 10 sheets make up one sheet bundle, "the next sheet" would refer to the 2nd to the 10th sheet. Furthermore, if "next sheet" refers to the next sheet in a sheet bundle that is aligned on the first tray 49, for example, if there are two consecutive jobs where each sheet bundle consists of 10 sheets, then "next sheet" will refer to the first sheet of the second sheet bundle (the 11th sheet counting from the job of the first sheet bundle). The pair of alignment plates 401 and 402 then align the next sheet, which has been temporarily received by the guide surface 4002, together with the sheet bundle that was aligned when this next sheet was temporarily received.

[0071] 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 next sheet is discharged from the discharge roller pair 42 with a widthwise displacement relative to the top sheet while the pair of alignment plates 401 and 402 are aligning the top sheet at the alignment position. 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 it moves downstream in the discharge direction, and so as it moves downstream in the discharge direction, and so as it moves upward. On the other hand, the guide surface 4002 is inclined at a second angle with respect to the horizontal direction, which is greater than the first angle, at the alignment position, and so as it moves downstream in the discharge direction, and so as it moves upward.

[0072] Furthermore, as shown in Figure 19(a), described later, which shows the alignment plates 401 and 402 in the alignment position, the upstream end of the guide surface 4002 in the discharge direction is located below the nip line N2, which is the line extending downstream in the discharge direction from the nip surfaces of the pair of conveying rollers, the upper conveying roller 41 and the lower conveying roller 48, when 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 (tip) of the sheet discharged from the discharge roller pair 42 can easily pass above the upstream end of the guide surface 4002. Note that if the angle of the nip line N2 with respect to the horizontal direction is large, the upstream end of the guide surface 4002 may be located above the nip point N1. However, in order to prevent the tip of the discharged sheet from getting caught on the upstream end of the guide surface 4002, it is preferable that the upstream end of the guide surface 4002 be located below the nip point N1 in the vertical direction.

[0073] As described above, in this embodiment, the angle of the guide surface 4002 with respect to the horizontal direction is made larger than the angle of the loading surface 49a with respect to the horizontal direction. This ensures that the vertical width of the first portion 4001a of the alignment surface 4001 is secured, and makes it easier to position the upstream end of the guide surface 4002 below the nip line N2, more preferably below the nip point N1. As a result, sheet alignment can be performed over a wide area of ​​the alignment surface 4001, and the discharged sheets are less likely to get caught on the upstream end of the guide surface 4002. If sheet alignment can be performed over a wide area of ​​the alignment surface 4001, the sheet loading capacity of the first tray 49, which can be aligned by the alignment plates 401 and 402, can be increased.

[0074] The sheet receiving surface 4003, as an inclined portion, is provided at the upstream end of the guide surface 4002 in the discharge direction when the pair of alignment plates 401 and 402 are in the alignment position. It is inclined inward in the width direction, towards the side where the uppermost sheet is located, as it moves downstream in the discharge direction, thereby guiding the next sheet discharged from the discharge roller pair 42 to the guide surface 4002. In other words, when the pair of alignment plates 401 and 402 are in the alignment position, the sheet receiving surface 4003 has the role of scooping up the leading edge of the sheet discharged from the discharge roller pair 42 and receiving it onto the guide surface 4002.

[0075] Such a sheet receiving surface 4003 is inclined downwards as it moves inward in the width direction when the pair of alignment plates 401 and 402 are in alignment position. This makes it easier for the sheet receiving surface 4003 to pick up the leading edge of a sheet that is weak in rigidity, for example, if it is discharged from the discharge roller pair 42 in a sagging manner. However, if the upstream end of the guide surface 4002 is close to the discharge roller pair 42, and 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 can easily pass over the guide surface 4002, the sheet receiving surface 4003 may be omitted.

[0076] In this embodiment, since guide surfaces 4002 are provided on the pair of alignment plates 401 and 402, as described later, even if the next sheet is discharged while the pair of alignment plates 401 and 402 are aligned with the sheet, the next sheet can be guided by the guide surfaces 4002. If such guide surfaces 4002 were not present, if the next sheet was discharged while the alignment plates 401 and 402 were in the aligned position, the next sheet may collide with one of the alignment plates, causing the sheet's orientation to be disrupted or the sheet to bend. In particular, as described later, if the spacing between sheets discharged continuously is narrowed to increase productivity, the sheets will be discharged while the alignment plates 401 and 402 are in the aligned position. In this embodiment, as described above, since there are guide surfaces 4002 that guide the sheet discharged from the discharge roller pair 42 while the alignment plates 401 and 402 are in the aligned position, the risk of the sheet colliding with one of the alignment plates can be reduced. The operation of the alignment plates 401 and 402 during sheet discharge will be described later.

[0077] [Drive configuration of the alignment plate and paddle] Next, the drive configuration of the pair of matching plates 401, 402 and the paddle 275 will be described using Figures 8 to 11. Figures 8 and 10 are perspective views of the area around the pair of matching plates 401, 402 when they are in the home position, while Figures 9 and 11 are perspective views of the area around the pair of matching plates 401, 402 when they have been lowered from the home position to the first position. In addition, while the jogger lifting HP detection sensor SN6 and the paddle lifting HP detection sensor SN9 are omitted in Figures 8 and 9 for illustrative purposes, they are also shown in Figures 10 and 11.

[0078] The alignment plate 401 on the front side (upper right side in Figures 8-11) moves in the width direction by the front side moving mechanism (movement mechanism) 410, and the alignment plate 402 on the rear side (lower left side in Figures 8-11) moves in the width direction by the rear side moving mechanism (movement mechanism) 420. In addition, the pair of alignment plates 401 and 402 move vertically by the alignment plate lifting mechanism 430, which acts as a lifting mechanism, and the paddle 275 moves vertically by the paddle lifting mechanism 440. The pair of alignment plates 401 and 402 are supported via a pair of swinging arms 403 and 404, and the paddle 275 is supported via a paddle arm 276, so that they can swing vertically with respect to the swing axis 405.

[0079] The pivot shaft 405 is positioned above the discharge roller pair 42, extending across its width. The position of the pivot shaft 405 with respect to the discharge direction is as close as possible to the discharge roller pair 42, and in this embodiment, it is located further upstream than the upstream end of the recess 49b of the first tray 49 in the discharge direction. The pair of pivot arms 403 and 404 are driven by a jogger lifting motor MT19, which acts as a matching member lifting unit (rotation drive unit), allowing them to swing vertically around the pivot shaft 405, which is positioned above the discharge roller pair 42. Specifically, the drive of the jogger lifting motor MT19 is transmitted to the pair of pivot arms 403 and 407 via the matching plate lifting mechanism 430, causing the pair of pivot arms 403 and 407 to swing vertically around the pivot shaft 405. The pair of alignment plates 401 and 402 are positioned on the inside of the pair of oscillating arms 403 and 404, on the side where the uppermost sheet is located in the width direction, and are rotatably connected to the pair of oscillating arms 403 and 404.

[0080] The pair of swing arms 403 and 404 are supported so as to be rotatable and so as to be able to move relative to each other along the axial direction with respect to the swing shaft 405. Therefore, the swing arms 403 and 404 do not swing simply by the rotation of the swing shaft 405. For this reason, the sheet loading device 400 has a matching plate lifting mechanism 430 as a drive transmission unit. The matching 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. In other words, in this embodiment, the matching plate lifting mechanism 430 has a pair of swing arms 403 and 404, a swing shaft 405, a transmission mechanism 431, a parallel shaft 432, a connecting part 433, an engagement hole 434, and a jogger lifting motor MT19.

[0081] The transmission mechanism 431 includes a gear 431a to which power is transmitted from the drive gear of the jogger lifting motor MT19, a pulley (not shown) that rotates integrally with the gear 431a, a pulley 431b fixed to the oscillating shaft 405, and a belt 431c stretched between the pulley on the gear 431a side and the pulley 431b. The driving force of the jogger lifting motor MT19 is transmitted to the oscillating shaft 405 via the gear 431a, the pulley (not shown), the belt 431c, and the pulley 432b.

[0082] The parallel shafts 432 are provided parallel to the pivot shaft 405 and are connected to the pivot shaft 405 by a connecting portion 433. In this embodiment, the parallel shafts 432 are positioned on the front and rear sides of the paddle 275, and each parallel shaft 432 is connected to the pivot shaft 405 by a connecting portion 433. Therefore, the pair of parallel shafts 432 rotate around the pivot shaft 405 when the pivot shaft 405 rotates. Engagement holes 434 are provided on the pair of pivot arms 403 and 404, respectively, and engage with the parallel shafts 432, causing the pair of pivot arms 403 and 404 to rotate together with the parallel shafts 432 when the parallel shafts 432 rotate around the pivot shaft 405. As a result, the pair of alignment plates 401 and 402, supported by the pair of pivot arms 403 and 404, move in the vertical direction.

[0083] Such an engagement hole 434 is a through-hole through which a parallel shaft 432 is inserted in an engageable manner, and through which the parallel shaft 432 and the swing arms 403 and 404 can move relative to each other within a predetermined range in the rotational direction about the swing axis 405. That is, the engagement hole 434 is a through-hole having a curved shape in the direction along the arc centered on the swing axis 405, and the inserted parallel shaft 432 can move relative to each other within a predetermined range in the direction along this arc. The parallel shaft 432 inserted through the engagement hole 434 engages with the upstream end of the engagement hole 434 in the discharge direction due to the weight of the swing arms 403 and 404 in the home position (second position) of Figure 8. Also, in the first position shown in Figure 9, the parallel shaft 432 inserted through the engagement hole 434 engages with the upstream end of the engagement hole 434 in the discharge direction due to the weight of the swing arms 403 and 404.

[0084] However, for example, when descending from the second position to the first position, if the pair of alignment plates 401 and 402 come into contact with a sheet or sheet bundle on the first tray 49 before reaching the first position, the pair of alignment plates 401 and 402 and the pair of swinging arms 403 and 404 will be raised higher than when they are in the first position. In this case, if the parallel shaft 432 and the pair of swinging arms 403 and 404 are connected in a way that prevents relative movement in the rotational direction, the jogger lifting motor MT19 will be driven by the amount of movement the pair of alignment plates 401 and 402 move until they reach the first position, which may cause damage to the sheet on the first tray 49 from the pair of alignment plates 401 and 402. In contrast, as described above, by making the parallel shaft 432 and the engagement hole 434 movable relative to each other within a predetermined range in the rotational direction, even if the pair of alignment plates 401 and 402 come into contact with the sheet, the parallel shaft 432 moves within the engagement hole 434, absorbing the amount of movement of the pair of alignment plates 401 and 402 as described above. As a result, damage to the sheet on the first tray 49 can be suppressed.

[0085] In the example described above, the raising and lowering of the pair of alignment plates 401 and 402 was performed by a single jogger lifting motor MT19. However, the raising and lowering of the pair of alignment plates 401 and 402 may also be performed by separate motors. For example, in the above configuration, a pivot shaft 405 may be provided for each of the alignment plates 401 and 402, and each pivot shaft 405 may be rotationally driven by a motor. With this configuration, the alignment plates 401 and 402 can be raised and lowered independently.

[0086] 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 pivot shaft 405. Therefore, the paddle arm 276 does not swing simply by the rotation of the pivot 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 motor MT22 to swing the paddle arm 276 around the pivot shaft 405, and includes a gear 442 to which the drive is transmitted from the drive gear 441 of the paddle lifting motor MT22, a pulley 443 that rotates integrally with the gear 442, a pulley 444 that is rotatably supported on the pivot shaft 405 and fixed to the paddle arm 276, and a belt 445 that is stretched between the pulley 443 and the pulley 444. The driving force of the paddle lifting motor MT22 is transmitted to the paddle arm 276 via drive gear 441, gear 442, pulley 443, belt 445, and pulley 444. As the paddle arm 276 swings around the pivot axis 405, the paddle 275, supported at the tip of the paddle arm 276, moves vertically between the transport position and the upper position described above.

[0087] The paddle 275 is rotationally driven by the discharge roller 1 motor MT6 (not shown in Figures 8-11) via the paddle drive mechanism 450. In other words, in this embodiment, the upper conveyor roller 41 and the paddle 275 share a common drive source. Therefore, while the upper conveyor roller 41 is rotationally driven, the paddle 275 also rotates. The rotational drive of the paddle 275 may also be performed by a separate motor. The paddle drive mechanism 450 transmits the drive of the discharge roller 1 motor MT6 to rotate the paddle 275, and has a first transmission unit 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 unit 451, a second transmission unit 453 to which the drive is transmitted from the transmission shaft 452, and a third transmission unit 454 to which the drive transmitted to the second transmission unit 453 is transmitted to the paddle 275.

[0088] The first transmission unit 451, the second transmission unit 453, and the third transmission unit 454 are each composed of various power transmission members such as gears, pulleys, and belts. The first transmission unit 451 is positioned rearward of the oscillating shaft 405 in the width direction, while the second transmission unit 453 and the third transmission unit 454 are positioned between a pair of alignment plates 401 and 402 in the width direction. The transmission shaft 452 is positioned above the oscillating shaft 405 and parallel to the oscillating shaft 405, and connects the first transmission unit 451 and the second transmission unit 453 in a drive-transmission manner. The output pulley 453a that outputs the drive input to the second transmission unit 453 and the input pulley 454a that receives the drive input to the third transmission unit 454 are integrated, and a belt 454c is stretched between the input pulley 454a of the third transmission unit 454 and the 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 rotatable relative to the pivot shaft 405. With this configuration, the driving force of the discharge roller 1 motor MT6, input from the rear to the first transmission unit 451, is transmitted to the paddle 275 via the transmission shaft 452, the second transmission unit 453, and the third transmission unit 454, causing the paddle 275 to rotate.

[0089] As described above, the front alignment plate 401 moves in the width direction by the front moving mechanism 410, and the rear alignment plate 402 moves in the width direction by the rear moving mechanism 420. The pair of alignment plates 401 and 402 are supported so as to be movable in the width direction relative to the pivot axis 405 via a pair of pivoting arms 403 and 404. The configuration of the front moving mechanism 410 and the rear moving mechanism 420 is the same. The front moving mechanism 410 has a gear 412 to which the drive of the drive gear 411 of the jogger 1 moving motor MT20 is transmitted, a pulley 413 that rotates integrally with the gear 412, a pair of pulleys 414 that are positioned outside the width direction of movement range of the alignment plate 401 in a direction parallel to the pivot axis 405, a belt 415 that is stretched over the pulleys 413 and the pair of pulleys 414, and a tension pulley 416 that applies tension to the belt 415. Of the belt 415, the portion stretched across the pair of pulleys 414 is parallel to the pivot axis 405, and a slide member 435 is fixed to a portion of the belt 415 parallel to the pivot axis 405. The slide member 435 is movable in the width direction together with the pivot arm 403, but is connected to the pivot arm 403 so as to be rotatable relative to the pivot arm 403, so as not to rotate even when the pivot arm 403 rotates around the pivot axis 405. Therefore, the rotational drive of the jogger 1 moving motor MT20 causes the portion of the belt 415 parallel to the pivot axis 405 to move parallel to the pivot axis 405, and the pivot arm 403 fixed to this portion moves in the width direction along the pivot axis 405. Since a matching plate 401 is supported on the pivot arm 403, the matching plate 401 moves in the width direction together with the pivot arm 403.

[0090] Similarly, the rear moving mechanism 420 includes a gear 422 to which the drive gear 421 of the jogger 2 moving motor MT21 is transmitted, a pulley 423 that rotates integrally with the gear 422, a pair of pulleys 424 positioned outside the widthwise range of movement of the alignment plate 402 in a direction parallel to the oscillating axis 405, a belt 425 stretched over the pulleys 423 and the pair of pulleys 424, and a tension pulley 426 that applies tension to the belt 425. The portion of the belt 425 stretched over the pair of pulleys 424 is parallel to the oscillating axis 405, and a slide member 435 is fixed to a part of the portion of the belt 425 parallel to the oscillating axis 405. The slide member 435 is movable in the widthwise direction together with the oscillating arm 404, but is connected to the oscillating arm 404 so as to be rotatable relative to the oscillating arm 404, so as not to rotate even if the oscillating arm 404 rotates around the oscillating axis 405. Therefore, the rotational drive of the jogger 2 moving motor MT21 causes the portion of the belt 425 parallel to the pivot axis 405 to move parallel to the pivot axis 405, and the pivot arm 404 fixed to this portion moves in the width direction along the pivot axis 405. Since the alignment plate 402 is supported on the pivot arm 404, the alignment plate 402 moves in the width direction together with the pivot arm 404.

[0091] With this configuration, the pair of matching plates 401 and 402 can move independently in the width direction by the drive of the jogger 1 moving motor MT20 and the jogger 2 moving motor MT21. Alternatively, the pair of matching plates 401 and 402 may be moved synchronously in the width direction by a single motor. Furthermore, the parallel shaft 432 for moving the pair of matching plates 401 and 402 in the vertical direction is arranged parallel to the oscillating shaft 405, and the engagement holes 434 provided in the oscillating arms 403 and 404 are through holes through which the parallel shaft 432 is inserted. Therefore, when the pair of matching plates 401 and 402 move, the engagement holes 434 engage with the parallel shaft 432, allowing the pair of matching plates 401 and 402 to move in the width direction. Furthermore, since the engagement hole 434 and the parallel axis 432 are engaged regardless of the widthwise position of the pair of alignment plates 401 and 402, the pair of alignment plates 401 and 402 can move vertically at any position in the widthwise direction.

[0092] [Regarding sensors around the alignment plate] Next, using Figures 10 and 11, we will describe the jogger lifting HP detection sensor SN6, jogger 1 HP detection sensor SN7, jogger 2 HP detection sensor SN8, and paddle lifting HP detection sensor SN9, which are used to detect the widthwise and vertical positions of the alignment plates 401 and 402, and the vertical position of the paddle 275. Each of these sensors is a photointerrupter equipped with a light-emitting unit and a light-receiving unit that receives light emitted from the light-emitting unit, facing the light-emitting unit. The sensor turns ON when a flag enters the space between the light-emitting unit and the light-receiving unit, blocking the light from the light-emitting unit.

[0093] First, a flag 406 is fixed to the oscillating shaft 405 or pulley 431b. A jogger lifting HP detection sensor SN6 is provided at the position through which the flag 406 passes. When the jogger lifting motor MT19 is rotated to raise and lower the pair of matching plates 401 and 402, this driving force is transmitted to the oscillating shaft 405 via the matching plate lifting mechanism 430, and the flag 406 rotates together with the oscillating shaft 405. Figure 10 shows the pair of matching plates 401 and 402 in their home position, that is, in the second position with respect to the lifting direction. In this state, the flag 406 has not entered the jogger lifting HP detection sensor SN6, and the sensor is in the OFF state. The stacker control unit 330 determines that the pair of matching plates 401 and 402 are in their home position with respect to the lifting direction.

[0094] Then, when the pair of matching plates 401 and 402 begin to descend from the second position, the flag 406 enters the jogger lifting HP detection sensor SN6, and the sensor turns ON. Furthermore, even when the pair of matching plates 401 and 402 descend and reach the first position shown in Figure 11, the flag 406 remains in the state of having entered the jogger lifting HP detection sensor SN6. The stacker control unit 330 determines that the pair of matching plates 401 and 402 are in the first position by, for example, driving the jogger lifting motor MT19 for a predetermined number of pulses or a predetermined time after the flag 406 has entered the jogger lifting HP detection sensor SN6.

[0095] Next, a flag 417 is fixed to a slide member 435 that is secured to the portion of the belt 415 used to move the front alignment plate 401 in the width direction, which is stretched over a pair of pulleys 414. Similarly, a flag 427 is fixed to a slide member 435 that is secured to the portion of the belt 425 used to move the rear alignment plate 402 in the width direction, which is stretched over a pair of pulleys 424. Jogger 1HP detection sensor SN7 and jogger 2HP detection sensor SN8 are provided at the positions where the flags 417 and 427 pass, respectively. When the jogger 1 moving motor MT20 is rotated to move the front alignment plate 401 in the width direction, this driving force is transmitted to the oscillating arm 403 via the front moving mechanism 410. At this time, the portion of the belt 415 of the front moving mechanism 410 that is stretched over the pair of pulleys 414 moves in the width direction, causing the flag 417 fixed to this portion to move in the width direction together with the front oscillating 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 alignment plate 402.

[0096] Figure 10 shows the pair of matching plates 401 and 402 in their home position in the width direction. In this state, flags 417 and 427 are entering the jogger 1HP detection sensor SN7 and jogger 2HP detection sensor SN8, respectively, and the sensors are ON. The stacker control unit 330 determines that the pair of matching plates 401 and 402 are in their home position in the width direction. When the pair of matching plates 401 and 402 move outward in the width direction from their home position, flags 417 and 427 exit the jogger 1HP detection sensor SN7 and jogger 2HP detection sensor SN8, respectively, and the sensors turn OFF. The stacker control unit 330 controls the width direction position of the pair of matching plates 401 and 402 by, for example, counting the number of pulses of the jogger 1 movement motor MT20 and jogger 2 movement motor MT21 when the jogger 1HP detection sensor SN7 and jogger 2HP detection sensor SN8 are OFF.

[0097] Next, a flag 277 is provided on the part of the paddle arm 276 that is rotatably supported on the pivot axis 405. A paddle lifting HP detection sensor SN9 is also provided at the position through which the flag 277 passes. When the paddle lifting motor MT22 is rotated to raise or lower the paddle 275, this driving force is transmitted to the paddle arm 276 via the paddle lifting mechanism 440, and the flag 277 swings together with the paddle arm 276 around the pivot axis 405. Figure 10 shows the state in which the paddle 275 is in the home position, i.e., the upper position. In this state, the flag 277 has entered the paddle lifting HP detection sensor SN9, and the sensor is ON. The stacker control unit 330 determines that the paddle 275 is in the home position in this state.

[0098] Then, when the paddle 275 begins to descend from the upper position, the flag 277 is released from the paddle lifting HP detection sensor SN9, and the sensor turns OFF. Furthermore, with the sensor still OFF, the paddle 275 descends and reaches the transport position shown in Figure 11. The stacker control unit 330 determines that the paddle 275 is in the transport position by, for example, driving the paddle lifting motor MT22 for a predetermined number of pulses or for a predetermined time after the flag 277 is released from the paddle lifting HP detection sensor SN9.

[0099] [Interlocking mechanism] Next, an interlocking mechanism 460 that changes the angle of a pair of alignment plates 401 and 402 in conjunction with the oscillation of a pair of oscillating arms 403 and 404 will be described using Figures 12 and 13. The pair of alignment plates 401 and 402 are rotatably connected to the pair of oscillating arms 403 and 404 around a pivot axis 465 and extend upstream of the pivot axis 465 in the discharge direction. In this embodiment, regardless of the position of the pair of oscillating arms 403 and 404 in the oscillation direction, the interlocking mechanism 460 rotates the alignment plates 401 and 402 with respect to the pivot axis 465 in conjunction with the oscillation of the pair of oscillating arms 403 and 404 so that the angle of the extension direction of the alignment plates 401 and 402 with respect to the horizontal direction remains approximately constant.

[0100] Figures 19(a) and 19(b), described later, show a state in which the pair of alignment plates 401 and 402 are in a first position with respect to the vertical direction and in an alignment position with respect to the width direction. Here, as shown in Figure 19(a), the line connecting the center P1 of the swing axis 405 and the center P2 of the pivot axis 465 is called the first virtual line α1, and the line connecting the center P2 of the pivot axis 465 and the position P3 of the upper end of the pair of alignment plates 401 and 402 in the discharge direction and in the alignment position is called the second virtual line α2. In this embodiment, the angle θ between the first virtual line α1 and the second virtual line α2 is set to be smaller in the second position than in the first position. The first position is the position in which the pair of alignment plates 401 and 402 can align with 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 position in the vertical direction as the home position shown in Figure 6. Also, as shown in Figure 19(a), in this embodiment, the angle θ between the first virtual line α1 and the second virtual line α2 is acute at the first position.

[0101] As described above, the swing arms 403 and 404 swing vertically about the pivot axis 405 via the alignment plate lifting mechanism 430 by the jogger lifting motor MT19. The interlocking mechanism 460 changes the angle θ between 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 pivot axis 405. This interlocking mechanism 460 will be explained in detail. The interlocking mechanism 460 is positioned inside the swing arms 403 and 404, respectively, and rotates the alignment plates 401 and 402 relative to the tips of the swing arms 403 and 404 in conjunction with the swinging motion of the swing arms 403 and 404. Since the configuration of the interlocking mechanism 460 that rotates the alignment plates 401 and 402 respectively is the same, Figures 12 and 13 will describe, as a representative example, the interlocking mechanism 460 that rotates the alignment plate 402 in conjunction with the swinging motion of the swinging arm 404.

[0102] The interlocking 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 pivot shaft 405, and its rotational phase around the pivot shaft 405 does not change regardless of the pivoting motion of the pivot arm 404. In this 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 around the pivot 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 multiple teeth formed on their outer circumferential surfaces. The toothed belt 463 has multiple teeth formed on its inner circumferential surface that mesh with the multiple teeth formed on the toothed pulleys 461 and 462, respectively.

[0103] Furthermore, in this embodiment, there is a spring 464 as a tension-applying part that applies tension to the toothed belt 463. The spring 464 connects the first portion 463a and the second portion 463b of the toothed belt 463 when the portion between the first portion 463a and the second portion 463b is bent. That is, with the toothed belt 463 between the first portion 463a and the second portion 463b bent, one end of the spring 464 is fixed to the first portion 463a by a fixing part 464a, and the other end of the spring 464 is fixed to the second portion 463b by a fixing part 464b. As a result, the tensile force of the spring 464 acts between the first portion 463a and the second portion 463b, applying tension to the toothed belt 463.

[0104] If no tension is applied to the toothed belt 463, the tolerances of the toothed pulleys 461 and 462 and the toothed belt 463 may cause the toothed belt 463 to become too tight or too loose. If the toothed belt 463 is too tight, it will become a load on the swinging arm 404. On the other hand, if the toothed belt 463 is too loose, it will be impossible to properly position the alignment plate 402 around the pivot axis 465. In other words, the alignment plate 402 will not be able to be in the correct position. In particular, the position of the alignment plate 402 is determined when the lower part of the toothed belt 463, which is stretched by the toothed pulleys 461 and 462, is taut. Therefore, if the lower part of the toothed belt 463 flexes, the alignment plate 402 will end up with its upstream end lower than the desired position. In order to apply tension to the toothed belt 463, for example, a tensioner could be provided to bias a part of the toothed belt 463 outward or inward; however, in this case, the device would become larger. Therefore, in this embodiment, as described above, tension is applied to the toothed belt 463 by flexing a part of the toothed belt 463 and providing a spring 464.

[0105] Figure 12 shows the alignment plate 402 in its home position (second position). When the jogger lifting motor MT19 is driven to lower the alignment plate 402 from this position, the swing arm 404 swings 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 its rotational phase is maintained. On the other hand, the toothed pulley 462, which is rotatably supported on a pivot shaft 465 provided at the tip of the swing arm 404, rotates via the toothed belt 463 stretched between the toothed pulley 461 and the toothed pulley 462 as the tip of the swing arm 404 lowers and its vertical position relative to the toothed pulley 461 changes.

[0106] As described above, since the toothed pulley 462 is fixed to the alignment plate 402, the alignment plate 402 also rotates together with the toothed pulley 462 around the pivot axis 465 due to the downward swinging of the swing arm 404. That is, the position in which the multiple teeth on the inner surface of the toothed belt 463 mesh with the multiple teeth on the outer surface of the toothed pulley 461 changes, and the toothed belt 463 rotates in the direction of arrow 463c in Figure 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 pivot axis 465 from the lower left to the upper right of Figure 12. As a result, the alignment plate 402 descends to the first position shown in Figure 13 while its posture, i.e., the angle of the second imaginary line α2 with respect to the horizontal direction, is generally maintained. When raising the alignment plate 402 from the first position to the second position, the toothed belt 463 and toothed pulley 462 rotate in the opposite direction to that described above, thereby generally maintaining the position of the alignment plate 402.

[0107] Although the toothed pulleys 461 and 462 are assumed to have the same number of teeth, they may be different. This allows for a change in the ratio of the angle between the matching plate 402 and the oscillating arm 404 (the angle θ between the first virtual line α1 and the second virtual line α2) to the amount of oscillation of the oscillating arm 404. For example, if the number of teeth of toothed pulley 462 is reduced compared to the number of teeth of toothed pulley 461, the amount of variation in the angle θ with respect to the amount of oscillation of the oscillating arm 404 will increase, and if the number of teeth of toothed pulley 462 is increased compared to the number of teeth of toothed pulley 461, the amount of variation in the angle θ with respect to the amount of oscillation of the oscillating arm 404 will decrease.

[0108] In this embodiment, the alignment plate 402 can be moved between the first and second positions while its orientation is generally maintained by the interlocking mechanism 460. For this reason, as will be described in detail later, the angle θ between the first virtual line α1 and the second virtual line α2 is smaller in the second position shown in Figures 8, 10, and 12 than in the first position shown in Figures 9, 11, and 13. That is, in this embodiment, the pair of alignment plates 401 and 402 can be moved between the first and second positions while generally maintaining an orientation in which they are extended upstream of the pivot axis 465 in the discharge direction relative to the pair of swinging arms 403 and 404.

[0109] For example, if a pair of alignment plates 401 and 402 are extended downstream of the pivot axis 465 in the discharge direction, and the angle of the pair of alignment plates 401 and 402 relative to a pair of swinging arms 403 and 404 is the same in the first and second positions, then 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 swinging arms 403 and 404. In this case, a large space is required above the first tray 49 to secure space for the alignment plates 401 and 402 in the second position. As a result, the second tray 71, which is above the first tray 49, cannot be lowered sufficiently, and the loading capacity of the sheets on the second tray 71 is reduced.

[0110] In contrast, in this embodiment, the pair of alignment plates 401 and 402 are movable between the first and second positions while generally maintaining a posture in which they extend upstream in the discharge direction from the pivot axis 465 relative to the pair of swinging arms 403 and 404. Therefore, even when the alignment plates 401 and 402 move to the second position, they do not protrude into the space above the swinging arms 403 and 404, or if they do protrude, the amount of protrusion is small. This makes it easier to secure the amount of downward movement of the second tray 71 above the first tray 49, and to secure the amount of sheets that can be loaded onto the second tray 71.

[0111] In the example described above, the interlocking mechanism 460 was constructed using a toothed pulley and a toothed belt, but these may also be constructed using multiple gears. That is, the interlocking mechanism 460 should be configured to rotate the alignment plates 401 and 402 around the pivot axis 465 in conjunction with the swinging motion of the swinging arms 403 and 404, so that the alignment plates 401 and 402 maintain their position even when the swinging arms 403 and 404 swing in the vertical direction. If the interlocking mechanism is constructed using a pulley and belt without teeth, it will be difficult to move the alignment plates 401 and 402 in the vertical direction while maintaining their position due to slippage between the pulley and belt. For this reason, it is preferable that the interlocking mechanism 460 be constructed using a toothed pulley and belt, as in this embodiment, or using multiple gears that mesh with each other.

[0112] [Shift Discharge Mode] In this embodiment, the sheet loading device 400 can perform a job in which sheets are aligned one by one using a pair of alignment plates 401 and 402, and this process is repeated multiple times to form a sheet bundle at the same position in the sheet width direction on the first tray 49. Examples of such jobs include the shift discharge mode and the straight discharge mode, which will be described later. First, the shift discharge mode will be described, in which sheets are moved (shifted) in the width direction and discharged onto the first tray 49 without binding, forming a sheet bundle consisting of multiple unbound sheets. In the shift discharge mode, for example, as shown in Figure 23(b), multiple unbound sheet bundles are shifted relative to each other in the width direction and discharged onto the first tray 49. An example of such a shift discharge mode will be described using Figures 14(a) to 22(b).

[0113] The stacker control unit 330 is capable of executing a shift discharge mode, and when the shift discharge mode is executed, it operates the pair of alignment plates 401 and 402 as follows. First, let's describe the case where a job is performed to load a second sheet bundle (second sheet bundle) onto the first tray 49, shifting it to one side in the width direction relative to a first sheet bundle (first sheet bundle) consisting of multiple sheets loaded on the first tray 49. In this case, the pair of alignment plates 401 and 402 align the first sheet bundle loaded on the first tray 49 at the first position, and then rise from the first position to the second position. Next, after the leading edge of the first sheet of the second sheet bundle following the first sheet bundle has been discharged from the discharge roller pair 42, the pair of alignment plates 401 and 402 descend from the second position to the first position, shifted to one side from the position where the first sheet bundle was aligned, and align the sheets included in the second sheet bundle.

[0114] The following describes the process starting with the discharge operation of the first sheet S11 of the first sheet bundle. Here, we will describe the case where the first sheet bundle is shifted to the front and loaded onto the first tray 49, and the next second sheet bundle is shifted to the rear and loaded onto the first sheet bundle. As shown in Figures 14(a) and (b), the sheet S11 conveyed on the straight path 28 passes through the first conveyor roller 201, and the position of the widthwise edge (side edge) of the sheet S11 is detected by the register detection sensor SN2. At this time, the pair of alignment plates 401 and 402 are positioned from the home position shown in Figures 6 and 7 to the sheet receiving position during the shift discharge mode. 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 widthwise edge (side edge) of the sheet at the position where the sheet S11 is loaded onto the first tray 49 (reference position). In Figures 14(a) and (b), the alignment plates 401 and 402 are shifted towards the front relative to their positions when the sheet is discharged with the center in the width direction as the reference point.

[0115] In this case, the pair of alignment plates 270, which act as shift members for aligning and shifting sheets on the processing tray 37, are also shifted to the front side from the center reference position in the width direction. That is, the pair of alignment plates 270 are located at the first width direction position when the pair of alignment plates 401 and 402 are located at the first receiving position where they receive sheets at a predetermined position on the first tray 49. Also, when the pair of alignment plates 401 and 402 are located at the second receiving position where they receive sheets at a position shifted to one side in the width direction (in this case, the front side) from the predetermined position on the first tray 49, the pair of alignment plates 270 are located at the second width direction position which is shifted to one side in the width direction (in this case, the front side) from the first width direction position.

[0116] Here, the pair of alignment plates 270 have guide surfaces that serve as shift member-side guides for guiding sheets that are transported toward the discharge roller pair 42 without being placed on the processing tray 37. The guide surfaces 270a are formed on the upper surfaces of the pair of alignment plates 270, on the side downstream in the transport direction from the pre-processing roller 36, and guide the sheets that have passed the pre-processing roller 36 toward the discharge roller pair 42. Also, in the state shown in Figures 14(a) and (b), the paddle 275 remains in the home position.

[0117] Note that the front side is the lower side of Figure 14(b), the rear side is the upper side of Figure 14(b), and Figure 14(a) is a cross-sectional view from the front side. The same applies to Figures 15(a) to 22(b). Furthermore, discharge of the sheet based on the widthwise center means, for example, that the sheet is discharged when the widthwise center of the straight path 28 and the widthwise center of the sheet are approximately aligned, and that the sheet is discharged without shifting it using the second conveyor roller 202 and the third conveyor roller 203.

[0118] Next, as shown in Figures 15(a) and (b), the stacker control unit 330 shifts the sheet S11 to the front side using the second transport roller 202 and the third transport roller 203 based on the detection result of the register detection sensor SN2. Then, the sheet S11 that has shifted to the front side is passed to the pre-processing roller 36, and further transported from the pre-processing roller 36 toward the discharge roller pair 42. At this time, the lower surface of the sheet S11 facing the discharge roller pair 42 is supported by the guide surface 270a formed on the upper surface of the pair of alignment plates 270 on the processing tray 37 that has 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 surface 270a. In this way, since the sheet S11 is discharged while being supported by the guide surface 270a, the sheet S11 is discharged from the discharge roller pair 42 while being held in place by the guide surface 270a.

[0119] Next, as shown in Figures 16(a) and (b), once the rear end (upstream end in the conveying direction) of the sheet S11 has passed the discharge roller pair 42, the paddle 275 is lowered to the conveying 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 sheet S11 is scooped in by the paddle 275, and the rear end of the sheet S11 is brought into contact with 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 shifted to the front side, and the third sheet S13 has reached the first conveying roller 201.

[0120] Next, as shown in Figures 17(a) and (b), the sheet S11 is aligned using a pair of alignment plates 401 and 402. At this time, since the sheet S11 is shifted to the front, the front alignment plate 401 is moved 10 mm to the rear without moving the rear alignment plate 402. In this state, the pair of alignment plates 401 and 402 are in the aligned position. Here, the receiving positions of the alignment plates 401 and 402 are 5 mm away from the widthwise end of the sheet at the reference position (a control-determined position) during shift discharge, so the front alignment plate 401 is moved 10 mm to the rear. Note that the widthwise end of the sheet at the reference position varies depending on the size of the sheet.

[0121] Furthermore, during the alignment of the sheet S11, the paddle 275 is raised to an upward position. The timing for raising the paddle 275 is before the alignment plate 401 reaches the alignment position. In this embodiment, the alignment plate 401 reaches the alignment position after the paddle 275 has moved away from the upper surface of the sheet. The timing for starting to raise the paddle 275 from the transport position and the timing for starting to move either or both of the alignment plates 401 and 402 from the receiving position to the alignment position is after a predetermined time has elapsed since the rear end of the sheet passed the sheet edge detection sensor SN3.

[0122] While the first sheet S11 is being aligned by the pair of alignment plates 401 and 402, the second sheet S12 begins to be discharged from the discharge roller pair 42. At this time, the second sheet S12 may be discharged with a widthwise displacement relative to the sheet S11 that is being aligned. For example, in Figure 17(b), the sheet S12 is discharged slightly shifted to the front side relative to the sheet S11. As a result, the sheet S12 being 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. Note that in Figure 17(a), the rear alignment plate 402 is shown, and it appears as if the sheet S12 is resting on the rear alignment plate 402, but as shown in Figure 17(b), the sheet S12 is not resting on the rear alignment plate 402. Also, while the second sheet S12 is being discharged, the third sheet S13 is being shifted to the front side by the second transport roller 202 and the third transport roller 203.

[0123] In the apparatus of this embodiment, the tolerance for the shift amount by the second conveyor roller 202 and the third conveyor roller 203 is 5 mm. During alignment, the front alignment plate 401 moves 10 mm to the rear from the receiving position of the sheet S1, and the alignment plate 401 at the receiving position is located 5 mm to the front from the widthwise end of the sheet at the reference position. Therefore, the position of the front alignment plate 401 at the alignment position is 5 mm to the rear from the widthwise end of the sheet at the reference position. Consequently, when the sheet is shifted by the second conveyor roller 202 and the third conveyor roller 203 by 5 mm to the front from the widthwise end of the sheet at the reference position, which is the maximum tolerance, and the sheet is discharged from the discharge roller pair 42 in this state, the sheet may be discharged shifted up to 10 mm to the front from the alignment surface 4001 of the front alignment plate 401.

[0124] Therefore, in this embodiment, the thickness of the guide surface 4002 in the width direction is set to 10 mm or more, for example, 11 mm. As a result, even if the second sheet S12 is discharged from the discharge roller pair 42 with a shift of 5 mm, which is the tolerance of the shift amount by the second conveyor roller 202 and the third conveyor roller 203, the guide surface 4002 can still guide the sheet S12.

[0125] Next, as shown in Figures 18(a) and (b), once the alignment operation of sheet S11 is complete, 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 forward from the alignment position. At this time, the rear alignment plate 402 does not move. At this time, the second sheet S12 is displaced from the guide surface 4002 of the front alignment plate 401 and becomes capable of falling onto the first sheet S11. Then, once the rear end of the second sheet S12 has passed the discharge roller pair 42, the paddle 275 is lowered to the transport position, and the sheet S12 is scraped towards the abutment member 271 while being dropped by the paddle 275. Furthermore, in the same manner as when the first sheet S11 was aligned, the front alignment plate 401 is moved to the alignment position to align sheet S12.

[0126] The above operation is performed on subsequent sheets included in the first sheet bundle, and the first sheet bundle is loaded onto the first tray 49 as shown in Figures 19(a) and (b). At this point, the first sheet S21 of the second sheet bundle is transported in succession to the first sheet bundle, but the second sheet bundle is loaded shifted to the rear side relative to the first sheet bundle. Therefore, the widthwise positions of the alignment plates 401 and 402 for aligning the second sheet bundle are different from the positions for aligning the first sheet bundle. Accordingly, in this embodiment, the pair of alignment plates 401 and 402 are raised before the discharge operation of the second sheet bundle is performed. In other words, the stacker control unit 330 uses the jogger lifting motor MT19 to raise a pair of alignment plates 401 and 402 from a first position to a second position before discharging the next sheet from the discharge roller pair 42 by shifting the first sheet bundle, which consists of multiple sheets stacked on the first tray 49, to one side in the width direction (in this case, the rear side).

[0127] Since the distance between the last sheet of the first sheet bundle and the first sheet S21 of the second sheet bundle is the same as the distance between multiple sheets in the first sheet bundle, if the pair of alignment plates 401 and 402 are raised as described above before the discharge operation of the second sheet bundle, there is a risk that the discharge operation of the first sheet S21 will not be completed in time, and the sheet S21 may come into contact with the alignment plates 401 and 402. For this reason, in this embodiment, as shown in Figures 19(a) and (b), the sheet S21 is temporarily placed in a buffer path 39 that branches off from between the second transport roller 202 and the third transport roller 203. This delays the timing at which the first sheet S21 of the second sheet bundle is discharged by the discharge roller pair 42.

[0128] Specifically, when the stacker control unit 330 loads a second sheet bundle, including the first sheet S21 (first sheet) and the second sheet S22 (second sheet), onto the first tray 49 by shifting it to one side in the width direction (in this case, the rear side) relative to the first sheet bundle loaded on the first tray 49, it temporarily places sheet S21 aside in the buffer path 39. Then, the third transport roller 203 and the pre-processing roller 36, which act as buffer transport units, transport sheet S21 and sheet S22 together toward the discharge roller pair 42. Specifically, sheet S21, which was aside in the buffer path 39, is transported toward the straight path 28 by the transport roller 208 and merged with the next sheet S22 being transported in the straight path 28. Then, the third transport roller 203 and the pre-processing roller 36 transport sheet S21 and sheet S22 together toward the discharge roller pair 42.

[0129] In this embodiment, the transport roller 208 is also a shift roller that can move the sheet in the width direction. Therefore, with the first sheet S21 nipped by the third transport roller 203 and the transport roller 208, the sheet S21 can be shifted to the front and rear sides. Thus, by nipping sheets S21 and S22 with the third transport roller 203, and with sheet S21 nipped by the transport roller 208 and sheet S22 nipped by the second transport roller 202, it is possible to shift sheets S21 and S22 while they are overlapping by moving the second transport roller 202, the third transport roller 203 and the transport roller 203 in the same direction. In Figures 19(a) and (b), sheets S21 and S22 are shifted to the rear side while they are overlapping.

[0130] As shown in Figures 20(a) and (b), the pair of alignment plates 401 and 402 are raised to the second position before the first and second sheets S21 and S22 of the second sheet bundle are discharged from the discharge roller pair 42. 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 around the pivot axis 465 and extend upstream of the pivot axis 465 in the discharge direction. In this configuration, the angle θ between the first imaginary line α1 and the second imaginary line α2 is smaller in the second position shown in Figure 20(a) than in the first position shown in Figure 19(a). In other words, when the swinging arms 403 and 404 are swung upward to move the alignment plates 401 and 402 to the second position, the angle of the alignment plates 401 and 402 relative to the swinging arms 403 and 404 changes so that the alignment plates 401 and 402 and the swinging arms 403 and 404 fold together.

[0131] In this case, if the angle θ between the first virtual line α1 and the second virtual line α2 is the same at both the first and second positions, the amount of oscillation of the oscillating arms 403 and 404 must be increased to allow the matching plates 401 and 402 to move sufficiently away from the first position, resulting in a longer time for the matching plates 401 and 402 to reach the second position. In contrast, in this embodiment, the angle θ between the first virtual line α1 and the second virtual line α2 is smaller at the second position than at the first position. Therefore, even if the amount of upward oscillation of the oscillating arms 403 and 404 is small, the matching plates 401 and 402 can be moved to a position sufficiently far from the first position. Consequently, the amount of oscillation of the oscillating arms 403 and 404 required to move the matching plates 401 and 402 from the first position to the second position can be reduced, and the time required to raise the matching plates 401 and 402 to the second position can be shortened.

[0132] Furthermore, in this embodiment, as described above, the angle θ between the first virtual line α1 and the second virtual line α2 at the first position is set to an acute angle. Therefore, the amount of change in angle θ when moving from the first position to the second position can be reduced. That is, the amount of oscillation of the oscillating arms 403 and 404 to the second position can be reduced. As a result, the time required to raise the alignment plates 401 and 402 to the second position can be shortened. In order to set the angle θ to an acute angle, it is preferable to make the length of the oscillating arms 403 and 404 sufficiently long, that is, to increase the distance between the oscillating axis 405 and the pivot axis 465. For this purpose, it is preferable to bring the position of the oscillating axis 405 in relation to the discharge direction as close as possible to the discharge roller pair 42. This makes it possible to position the alignment plates 401 and 402 at the first position even if the angle θ is small.

[0133] If the alignment plates 401 and 402 can be raised from the first position to the second position in a short time, then by simply temporarily holding the first sheet S21 of the second sheet bundle, the alignment plates 401 and 402 can be raised to the second position in time for the discharge of this first sheet S21. In other words, if the alignment plates 401 and 402 cannot be raised from the first position to the second position in a short time, there is a risk that, for example, the transport of the first sheet S21 of the second sheet bundle will have to be stopped, and the transport of the sheet S21 will have to be started only after waiting for the alignment plates 401 and 402 to rise to the second position. In this case, productivity in the shift discharge mode will decrease. In contrast, in this embodiment, since the alignment plates 401 and 402 can be raised from the first position to the second position in a short time, productivity can be improved.

[0134] Furthermore, in this embodiment, as shown in Figures 20(a) and (b), the alignment plates 401 and 402 are raised to the second position before being moved to the rear. That is, since the second sheet bundle is shifted to the rear and discharged, the alignment plates 401 and 402 are moved to the rear in accordance with this. If the alignment plates 401 and 402 were moved to the rear at the first position, the loading capacity of the already loaded first sheet bundle would be disrupted, so the alignment plates 401 and 402 are raised to the second position before being moved to the rear. Note that even if the alignment plates 401 and 402 have not yet reached the second position, they may be moved to the rear while being raised as long as they are away from the top sheet of the already loaded first sheet bundle.

[0135] Next, as shown in Figures 21(a) and (b), once the rear ends of sheets S21 and S22 have passed the discharge roller pair 42, the paddle 275 is lowered to the transport position, and the sheets S21 and S22 are scraped towards the abutment member 271 while being dropped by the paddle 275. At this time, the third sheet S23 of the second sheet bundle is transported to the pre-processing roller 36 with the sheet shifted to the rear.

[0136] Next, as shown in Figures 22(a) and (b), the seats S21 and S22 are aligned using a pair of alignment plates 401 and 402. At this time, since seats S21 and S22 are shifted to the rear side, the rear alignment plate 402 is moved 10 mm towards the front without moving the front alignment plate 401. In this state, the pair of alignment plates 401 and 402 are in the aligned position. Also, while seats S21 and S22 are being aligned, the paddle 275 is raised to the upper position.

[0137] While the first and second sheets S21 and S22 are being aligned by the pair of alignment plates 401 and 402, the third sheet S23 begins to be discharged from the discharge roller pair 42. In this case as well, as explained in Figures 17(a) and (b), when sheet S23 is discharged slightly shifted to the rear side relative to sheets S21 and S22, sheet S23 is guided above the alignment surface 4001 by the guide surface 4002 of the rear alignment plate 402. Once the alignment operation of sheets S21 and S22 is complete, the rear alignment plate 402 is moved from the alignment position to the sheet receiving position, and then the paddle 275 is lowered to the transport position, causing the third sheet S23 to be dropped and scraped towards the abutment member 271. Furthermore, as with the alignment of sheets S21 and S22, the rear alignment plate 402 is moved to the alignment position to align sheet S23. This operation is performed until the last sheet of the second sheet bundle. During the discharge of the final sheet, the alignment plates 401 and 402 are returned to their receiving positions. Once the rear end of the final sheet has passed the discharge roller pair 42, the rear alignment plate 402 is moved to the front to align the final sheet, and the job is completed. At the end of the job, the pair of alignment plates 401 and 402 are returned to their home positions. The positions of the alignment plates 401 and 402 at the end of the job will be described later.

[0138] [Straight discharge mode] Next, we will describe the straight discharge mode, in which sheets are discharged onto the first tray 49 without shifting or binding, forming a sheet bundle consisting of multiple unbound sheets. In the straight discharge mode, for example, as shown in Figure 23(a), multiple unbound sheet bundles are discharged onto the first tray 49 without shifting. That is, the stacker control unit 330 is capable of executing the straight discharge mode. The basic operation of each part is the same as in the shift discharge mode described above, but it differs from the shift discharge mode in that the sheets are discharged without shifting. 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.

[0139] [Regarding the consistency of sheet bundles from the second bundle onwards] In this case, when the shift discharge mode described above is executed, after aligning the first sheet bundle on the first tray 49, when the pair of alignment plates 401 and 402 are moved from the second position (which may hereafter be called the retracted position) to the first position (which may hereafter be called the alignment-possible position) in order to align the first sheet of the second sheet bundle, there is a risk that the alignment of the already loaded first sheet bundle may be disrupted.

[0140] For example, consider the case where a second sheet bundle is discharged by shifting it to the other side in the width direction (in this case, the rear side) on top of a first sheet bundle ST1 that has been discharged by shifting it to one side in the width direction (in this case, the front side). In this case, the pair of alignment plates 401 and 402 rise to the retracted position after aligning the last sheet of the first sheet bundle, then descend to the alignment-possible position while moving to the rear side, and then align the first sheet of the second sheet bundle that has been discharged by shifting it to the rear side. At this time, the rear alignment plate 402 descends to the part where there is no sheet, but the front alignment plate 401 ends up on the top sheet SU of the first sheet bundle ST1 that is already loaded on the first tray 49. In this case, if the pair of alignment plates 401 and 402 suddenly descend from the retracted position to the alignment position, as shown in Figure 24, the front alignment plate 401 may come into strong contact with the top sheet SU of the already stacked first sheet bundle ST1, causing the sheet SU to shift from the other already stacked sheets, thus disrupting the alignment of the first sheet bundle ST1.

[0141] [Descending motion of the alignment plate] Therefore, in this embodiment, as described above, when moving the pair of alignment plates 401 and 402 in the shift direction (for example, to the rear side) from the retracted position to the alignment-possible position, at least the alignment plate located on the upstream side in the shift direction (for example, the front alignment plate 401) of the pair of alignment plates 401 and 402 is temporarily stopped from descending from the retracted position to the alignment-possible position before it contacts the upper surface of the first bundle of already stacked sheets loaded on the first tray 49. Then, the alignment plate 401 is lowered again to contact the upper surface of the already stacked sheets.

[0142] The downward movement of the alignment plates 401 and 402 will be explained using Figures 25 to 28(b). Note that the paddle 275 is omitted in Figures 25 to 28(a). Figure 28(b) is an enlarged view of the area around the engagement hole 434 in Figure 28(a). Figure 25 shows the state in which the alignment of the first sheet bundle ST1, which has been shifted to the front side, is completed, as shown in Figures 19(a) and (b) above. In this state, the pair of alignment plates 401 and 402 are in the alignment-possible position. Next, the stacker control unit 330 moves the pair of alignment plates 401 and 402 to the retracted position, as shown in Figure 26, in order to discharge the first sheet of the second sheet bundle, which has been shifted to the rear side, onto the first tray 49. Also, the pair of alignment plates 401 and 402 are moved to the rear side in the retracted position. This state in Figure 26 is the same as the state shown in Figures 20(a) and (b) above.

[0143] Next, the stacker control unit 330 lowers the pair of alignment plates 401 and 402 from the retracted position toward the alignment-possible position, and as shown in Figure 27, temporarily stops the descent of the pair of alignment plates 401 and 402 before they come into contact with the upper surface of the top sheet (already stacked sheet) SU of the first sheet bundle ST1. The position where the descent of the pair of alignment plates 401 and 402 is temporarily stopped (temporary stop position) is above the upper surface of the top sheet when the maximum stacking capacity of sheets is stacked on the first tray 49. For example, after the flag 406 enters the jogger lifting HP detection sensor SN6, the stacker control unit 330 drives the jogger lifting motor MT19 for a second predetermined number of pulses which is less than the predetermined number of pulses mentioned above, or for a second predetermined time which is shorter than the predetermined time, thereby stopping the pair of alignment plates 401 and 402 at a position above the alignment-possible position and above the top sheet of the already stacked sheet, which is the temporary stop position. The predetermined number of pulses and predetermined time are the number of pulses and time from when the flag 406 enters the jogger lifting HP detection sensor SN6 until the pair of matching plates 401 and 402 descend to the matching position (first position).

[0144] Then, the stacker control unit 330 lowers the pair of alignment plates 401 and 402 again, bringing the front alignment plate 401 into contact with the top sheet SU of the first sheet bundle ST1, as shown in Figure 28(a). The timing for lowering the pair of alignment plates 401 and 402 again is, for example, a third predetermined time after the stacker control unit 330 stops driving the jogger lifting motor MT19. This timing is after the descent of the pair of alignment plates 401 and 402 has reliably stopped, as follows.

[0145] When lowering the pair of alignment plates 401 and 402, as described above, the stacker control unit 330 controls the jogger lifting motor MT19 to rotate the pivot shaft 405, causing the parallel shaft 432 to rotate around the pivot shaft 405 via the connecting part 433. At this time, the parallel shaft 432 moves relative to the engagement hole 434, and the parallel shaft 432 moves away from a part 434a of the engagement hole 434. The part 434a of the engagement hole 434 is the part that contacts the parallel shaft 432 and supports the weight of the pivot arms 403 and 404 and the pair of alignment plates 401 and 402, and is the upstream end of the engagement hole 434 in the direction in which the pivot arms 403 and 404 rotate downward around the pivot shaft 405.

[0146] When the parallel shaft 432 moves away from a portion 434a of the engagement hole 434, the oscillating arms 403, 404 and the pair of alignment plates 401, 402 descend by their own weight, lagging behind the rotation of the oscillating shaft 405, and the engagement holes 434 provided in the oscillating arms 403, 404 also rotate around the oscillating shaft 405. When the rotation of the oscillating shaft 405 is stopped in order to temporarily stop the pair of alignment plates 401, 402 in a stopping position, the rotation of the parallel shaft 432 around the oscillating shaft 405 also stops. Then, the descent of the pair of alignment plates 401, 402 stops as a portion 434a of the engagement hole 434, which has rotated lagging behind the parallel shaft 432, comes into contact with the parallel shaft 432. After the pair of alignment plates 401 and 402 have stopped, the rotation of the pivot shaft 405 is restarted, causing the pair of alignment plates 401 and 402 to descend further, so that the front alignment plate 401 comes into contact with the upper surface of the already loaded sheet SU, as shown in Figure 28(a).

[0147] When the front alignment plate 401 is in contact with the upper surface of the already loaded sheet SU, as shown in Figure 28(b), the front parallel shaft 432 and a part 434a of the engagement hole 434 provided in the front swing arm 403 separate, and a gap exists between them. That is, when the descent of the pair of alignment plates 401 and 402 is temporarily stopped and then the rotation of the swing shaft 405 is resumed, the parallel shaft 432 separates from the part 434a of the engagement hole 434, and the pair of alignment plates 401 and 402 descend due to their own weight. At this time, the rotation of the swing shaft 405 is performed by an amount equivalent to the amount required for the pair of alignment plates 401 and 402 to move to the alignment position, but the front alignment plate 401, by contacting the upper surface of the already loaded sheet SU, stops above the alignment position by the height of the first sheet bundle ST1. Therefore, the front alignment plate 401 will eventually descend due to its own weight and come into contact with the upper surface of the already loaded sheet SU, regardless of the amount of rotation of the pivot shaft 405, and will come to a stop.

[0148] In this embodiment, the descent of the alignment plates 401 and 402 is temporarily stopped before being allowed to descend again. As a result, the front alignment plate 401 descends from its temporary stopping position due to its own weight and contacts the upper surface of the already loaded sheet SU. Therefore, compared to the case where the alignment plate 401 is lowered all at once from the retracted position to the alignment-possible position, the alignment plate 401 will contact the upper surface of the already loaded sheet SU with less force. That is, if the alignment plate 401 is lowered all at once from the retracted position to the alignment-possible position, the alignment plate 401 will descend from the retracted position due to its own weight and contact the upper surface of the already loaded sheet SU with force. In contrast, by allowing the alignment plate 401 to descend again from its temporary stopping position, the alignment plate 401 descends from a position lower than the retracted position due to its own weight, and the force with which it contacts the upper surface of the already loaded sheet SU is weaker than when it is lowered from the retracted position due to its own weight. As a result, it is possible to suppress disruption of the alignment of the first sheet bundle ST1, such as the already stacked sheets SU shifting from other sheets. Therefore, according to this embodiment, it is possible to ensure alignment of the next sheet to be stacked while suppressing disruption of the alignment of the sheets already stacked on the first tray 49.

[0149] Furthermore, in this embodiment, the timing for restarting the descent of the pair of alignment plates 401 and 402 after they have been stopped at the stop position is set to after a portion 434a of the engagement hole 434 contacts the parallel shaft 432, as described above. Therefore, the descent of the pair of alignment plates 401 and 402 can be restarted only after the descent has been reliably stopped. Note that if the rotation of the pivot shaft 405 is restarted before a portion 434a of the engagement hole 434 contacts the parallel shaft 432, the descent of the pair of alignment plates 401 and 402 will proceed without stopping, which is no different from the case where the pair of alignment plates 401 and 402 are lowered all at once from the retracted position to the alignment position.

[0150] In the example described above, the case where the first sheet bundle ST1 is shifted to the front and the second sheet bundle is shifted to the rear was explained, but the reverse is also possible. In this case, since the second sheet bundle is shifted to the front, the rear alignment plate 402 will come into contact with the upper surface of the top sheet (pre-loaded sheet) SU of the first sheet bundle ST1. Therefore, the rear alignment plate 402 will come into weak contact with the upper surface of the pre-loaded sheet SU, similar to the alignment plate 401 described above.

[0151] Furthermore, in the above example, a configuration was described in which the raising and lowering of the pair of alignment plates 401 and 402 is performed by a single jogger lifting motor MT19. However, as mentioned above, if the raising and lowering of the pair of alignment plates 401 and 402 is performed by separate motors, when lowering the pair of alignment plates 401 and 402 from the retracted position toward the alignment-possible position, the alignment plate on the side that contacts the upper surface of the already loaded sheet SU may be stopped at a stop position before resuming its descent.

[0152] Furthermore, in the above example, we described the case in shift discharge mode where control is performed to stop the pair of alignment plates 401 and 402 at a stop position when they are lowered from the retracted position to the alignment position, but such control may also be performed in straight discharge mode. Moreover, such control may be performed regardless of the discharge mode even when there is no sheet on the first tray 49.

[0153] In straight discharge mode, when lowering the pair of alignment plates 401 and 402 from the retracted position to the alignment position, the alignment plate 401 temporarily stops descending above the sheet loaded on the first tray 49 during the descent from the retracted position to the alignment position, and then descends again. Also, if there is no sheet on the first tray 49, when lowering the pair of alignment plates 401 and 402 from the retracted position to the alignment position, the alignment plate 401 temporarily stops descending before contacting the first tray 49 during the descent from the retracted position to the alignment position, and then descends again.

[0154] In the configuration where the alignment plate is raised and lowered in straight discharge mode, there is a possibility that the alignment plate may hit the already loaded sheet or the first tray 49. Therefore, as described above, the alignment plate may be stopped at a stopping position and then lowered again. The case where there is no sheet on the first tray 49 corresponds to the case when aligning the first sheet in shift discharge mode or straight discharge mode. In such cases, stopping the alignment plate at a stopping position and then lowering it again can suppress the alignment plate from strongly contacting the first tray 49, and for example, noise during the lowering operation of the alignment plate can be reduced.

[0155] <Second Embodiment> The second embodiment will be described using Figures 29(a) to (c). In the first embodiment described above, a configuration was described in which a pair of alignment plates 401 and 402 descend by their own weight. In contrast, in this embodiment, the pair of alignment plates 401 and 402 are lowered by rotating them with a drive. The other configurations and operations are the same as in the first embodiment described above, so the same reference numerals are used for similar components, and their description and illustration are omitted or simplified. The following description will focus on the differences from the first embodiment.

[0156] In the sheet loading device 400A of this embodiment, the pair of alignment plates 401 and 402 are raised and lowered by directly rotating the swing arms 403 and 404 using the swing shaft 405. For example, the swing arms 403 and 404 are fixed to the swing shaft 405. In this case, the swing shaft 405 is configured to be movable in the shift direction. The relationship between the swing arms 403 and 404 and the pair of alignment plates 401 and 402 is the same as in the first embodiment described above.

[0157] The stacker control unit 330 moves the pair of alignment plates 401 and 402 to the retracted position, as shown in Figure 29(a), in order to discharge the first sheet of the second sheet bundle that has shifted to the front side onto the first tray 49. In addition, the pair of alignment plates 401 and 402 are moved to the rear side from the retracted position. The state in Figure 29(a) is the same as the state shown in Figures 20(a) and (b) above.

[0158] Next, the stacker control unit 330 lowers the pair of alignment plates 401 and 402 from the retracted position towards the alignment-possible position, and as shown in Figure 29(b), temporarily stops the descent of the pair of alignment plates 401 and 402 before they come into contact with the upper surface of the top sheet (already stacked sheet) SU of the first sheet bundle ST1. At this time, the pair of swing arms 403 and 404 are directly rotated by rotating the swing shaft 405, causing the pair of alignment plates 401 and 402 to descend. Then, by stopping the rotation of the swing shaft 405, the rotation of the swing arms 403 and 404 is stopped, and the descent of the pair of alignment plates 401 and 402 is temporarily stopped. Then, the stacker control unit 330 lowers the pair of alignment plates 401 and 402 again, and as shown in Figure 29(c), the front alignment plate 401 comes into contact with the upper surface of the top sheet (already stacked sheet) SU of the first sheet bundle ST1.

[0159] In this embodiment, the aligning plates 401 and 402 are temporarily stopped from descending before being lowered again. As a result, the front aligning plate 401 descends from its temporary stopping position and comes into contact with the upper surface of the already loaded sheet SU. Therefore, compared to the case where the aligning plate 401 is lowered all at once from the retracted position to the alignment-possible position, the aligning plate 401 comes into contact with the upper surface of the already loaded sheet SU more weakly. This prevents the already loaded sheet SU from shifting from other sheets, thus preventing disruption of the alignment of the first sheet bundle ST1. Accordingly, this embodiment allows for alignment of the next sheet to be loaded while suppressing disruption of the alignment of the sheets already loaded on the first tray 49.

[0160] Furthermore, in this embodiment, in addition to temporarily stopping the pair of alignment plates 401 and 402 during their descent as described above, they may also be decelerated. That is, in this embodiment, the pair of alignment plates 401 and 402 are raised and lowered by directly rotating the swing arms 403 and 404 with the swing shaft 405, so the descent speed of the alignment plates 401 and 402 can be changed by controlling the rotation speed of the swing shaft 405.

[0161] In this case, the stacker control unit 330 lowers the pair of alignment plates 401 and 402 from the retracted position to the alignment position, decelerating the alignment plate 401 from the first speed to the second speed before it contacts the upper surface of the already stacked sheet SU, and then lowering it again at a third speed that is slower than the first speed to contact the upper surface of the already stacked sheet SU. The third speed may be the same as the second speed. Furthermore, the third speed may be slower than the first speed, faster than the second speed, and even slower than the second speed.

[0162] In this way, when the alignment plates 401 and 402 are lowered, the lowering speed is temporarily reduced, and then the pair of alignment plates 401 and 402 are lowered again at a slower speed than the initial lowering speed. This results in the alignment plate 401 making weaker contact with the upper surface of the already loaded sheet SU compared to when the front alignment plate 401 is lowered at a constant speed from the retracted position to the alignment-possible position. As a result, it is possible to suppress the disruption of the alignment of the first sheet bundle ST1, such as the already loaded sheet SU shifting from other sheets. Therefore, even in this configuration, it is possible to align the next sheet to be loaded while suppressing the disruption of the alignment of the sheets already loaded on the first tray 49. Furthermore, if the third speed is the same as the second speed, when the pair of alignment plates 401 and 402 are lowered, after decelerating from the first speed to the second speed, they will continue to descend at the second speed, thus reducing the number of speed changes.

[0163] Furthermore, in this embodiment as well, the raising and lowering operations of the pair of alignment plates 401 and 402 may be performed by separate motors. In this case, when lowering the pair of alignment plates 401 and 402 from the retracted position toward the alignment-possible position, only the alignment plate on the side that contacts the already loaded sheet SU may be stopped at the stop position before resuming its descent.

[0164] Furthermore, in this embodiment as well, the above control may be performed even when there is no sheet on the first tray 49, regardless of whether it is in straight discharge mode or discharge mode, as in the first embodiment. The control for stopping the pair of matching plates 401 and 402 at the stop position is the same as described in the first embodiment. When reducing the descent speed, it is as follows.

[0165] In straight discharge mode, when lowering the pair of alignment plates 401 and 402 from the retracted position to the alignment position, the alignment plate 401 is decelerated to a second speed above the sheet loaded on the first tray 49 while the pair of alignment plates 401 and 402 are lowering from the retracted position to the alignment position, and then lowered again at the third speed. Also, regardless of the discharge mode, if there is no sheet on the first tray 49, when lowering the pair of alignment plates 401 and 402 from the retracted position to the alignment position, the alignment plate 401 is decelerated to a second speed before it contacts the first tray 49 while the pair of alignment plates 401 and 402 are lowering from the retracted position to the alignment position, and then lowered again at the third speed.

[0166] <Other Embodiments> In the above-described embodiment, a configuration in which a binding process is performed as a predetermined process in the processing unit was explained. However, the predetermined process is not limited to binding, but may also be folding, shifting, punching, creasing, laminating, etc. Furthermore, in the above-described embodiment, an example was described in which the control of the area around the first tray 49 of the sheet processing apparatus B was performed by the stacker control unit 330 (CPU 331). However, this control may also be performed by the control unit 310 (CPU 311) of the image forming apparatus A. [Explanation of Symbols]

[0167] 3. Image forming unit 36. Roller before processing (conveyor section) 42...Discharge roller pair (discharge section) 49...First tray (loading tray) 270...Matching plate (shift section) 330...Stacker Control Unit (Control Unit) 401, 402...Matching plate (1st matching part, 2nd matching part) 403, 404... Oscillating Arm 405...Oscillating shaft 410... Front side moving mechanism (moving mechanism) 420...Rear side movement mechanism (movement mechanism) 430... Alignment plate lifting mechanism (lifting mechanism) 432...parallel axis 433...Connection part 434...Engagement holes 1000...Image forming system A...Image forming apparatus B... Sheet processing device MT19... Jogger lifting motor (rotary drive unit)

Claims

1. A conveying unit that conveys the sheet in the conveying direction, A shifting unit that shifts the sheet conveyed by the conveying unit in a sheet width direction intersecting the conveying direction, A loading tray for loading the sheets, A discharge unit that discharges sheets toward the aforementioned loading tray, A first alignment part and a second alignment part that act on both ends in the width direction of the sheet bundle loaded on the aforementioned loading tray to align the sheet bundle, The first alignment unit and the second alignment unit are set up in a retracted position above the sheet that is shifted by the shift unit and discharged by the discharge unit, and a lifting mechanism is provided to raise and lower the sheet that has been discharged onto the loading tray to an alignment position where it can be aligned. A moving mechanism for moving the first alignment section and the second alignment section in the sheet width direction, The system comprises a control unit that controls the lifting mechanism and the moving mechanism, In the shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and lowers them from the retracted position to the alignment-possible position, A sheet loading device characterized in that, of the first and second alignment sections, at least the alignment section located on the upstream side in the shift direction is lowered from the retracted position to the alignment-possible position, the lowering of the alignment section is temporarily stopped before it contacts the upper surface of the first bundle of already loaded sheets loaded on the loading tray, and then lowered again to contact the upper surface of the already loaded sheets.

2. In the shift discharge mode, when the first and second alignment units are moved in the shift direction to align the second and subsequent sheet bundles at the first and second alignment units, and are lowered from the retracted position to the alignment-possible position, the sheet loading device according to claim 1 is characterized in that, while the first and second alignment units are lowered from the retracted position to the alignment-possible position, the descent of the alignment units is temporarily stopped before the alignment units contact the upper surface of the first bundle of already loaded sheets loaded on the loading tray, and then the descent is restarted.

3. The sheet loading device according to claim 1, wherein, in the shift discharge mode and the straight discharge mode in which a sheet is discharged onto the loading tray without shifting it using the shift unit, when there is no sheet on the loading tray, the control unit lowers the first alignment unit and the second alignment unit from the retracted position to the alignment-possible position, and in the process of lowering the first alignment unit and the second alignment unit from the retracted position to the alignment-possible position, the control unit temporarily stops the descent of the alignment unit before it contacts the loading tray, and then lowers it again.

4. The aforementioned lifting mechanism is A pair of swinging arms that rotatably support the first and second alignment sections, A pivot shaft that supports the pair of pivoting arms so that they can pivot, A parallel axis arranged parallel to the aforementioned pivot axis, A connecting part that connects the aforementioned pivot shaft and the aforementioned parallel shaft, The pair of swing arms are provided with engagement holes through which the parallel shafts are inserted in an engageable manner and through which the parallel shafts can move relative to each other within a predetermined range about the swing axis, It has a rotational drive unit that rotates the aforementioned oscillating shaft, In the shift discharge mode, when the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles at the first and second alignment units, and lowers them from the retracted position to the alignment-possible position, By controlling the rotation drive unit to rotate the pivot shaft, the parallel shaft connected to the pivot shaft by the connecting unit rotates around the pivot shaft, and as the parallel shaft moves away from a part of the engagement hole, the alignment unit descends toward the alignment position due to its own weight. Before the alignment part contacts the upper surface of the first bundle of already loaded sheets placed on the loading tray, the rotation of the pivot shaft is temporarily stopped. The sheet loading device according to claim 1, characterized in that, after the alignment portion descends due to its own weight and a part of the engagement hole comes into contact with the parallel axis, the rotation of the oscillating axis is restarted to bring the alignment portion into contact with the upper surface of the already loaded sheet.

5. The sheet loading device according to claim 4, characterized in that, of the first and second alignment portions, the alignment portion located on the upstream side in the shift direction is in contact with the upper surface of the already loaded sheet, and there is a gap between a part of the engagement hole and the parallel axis.

6. An image forming unit that forms an image on a sheet, A conveying unit that conveys the sheet on which the image has been formed in the image forming unit in the conveying direction, A shifting unit that shifts the sheet conveyed by the conveying unit in a sheet width direction intersecting the conveying direction, A loading tray for loading the sheets, A discharge unit that discharges sheets toward the aforementioned loading tray, A first alignment part and a second alignment part that act on both ends in the width direction of the sheet bundle loaded on the aforementioned loading tray to align the sheet bundle, The first alignment unit and the second alignment unit are set up in a retracted position above the sheet that is shifted by the shift unit and discharged by the discharge unit, and a lifting mechanism is provided to raise and lower the sheet that has been discharged onto the loading tray to an alignment position where it can be aligned. A moving mechanism for moving the first alignment section and the second alignment section in the sheet width direction, The system comprises a control unit that controls the lifting mechanism and the moving mechanism, In the shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and lowers them from the retracted position to the alignment-possible position, An image forming system characterized in that, of the first and second alignment sections, at least the alignment section located on the upstream side in the shift direction is lowered from the retracted position to the alignment-possible position, the lowering of the alignment section is temporarily stopped before it contacts the upper surface of the first bundle of already stacked sheets loaded on the loading tray, and then lowered again to contact the upper surface of the already stacked sheets.

7. A conveying unit that conveys the sheet in the conveying direction, A shifting unit that shifts the sheet conveyed by the conveying unit in a sheet width direction intersecting the conveying direction, A loading tray for loading the sheets, A discharge unit that discharges sheets toward the aforementioned loading tray, A first alignment part and a second alignment part that act on both ends in the width direction of the sheet bundle loaded on the aforementioned loading tray to align the sheet bundle, The first alignment unit and the second alignment unit are set up in a retracted position above the sheet that is shifted by the shift unit and discharged by the discharge unit, and a lifting mechanism is provided to raise and lower the sheet that has been discharged onto the loading tray to an alignment position where it can be aligned. A moving mechanism for moving the first alignment section and the second alignment section in the sheet width direction, The system comprises a control unit that controls the lifting mechanism and the moving mechanism, In the shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and lowers them from the retracted position to the alignment-possible position, A sheet loading device characterized in that, of the first and second alignment sections, at least the alignment section located on the upstream side in the shift direction is decelerated from a first speed to a second speed before contacting the upper surface of the first bundle of already loaded sheets loaded on the loading tray while being lowered from the retracted position to the alignment-possible position, and then lowered again at a third speed slower than the first speed to contact the upper surface of the already loaded sheets.

8. In the shift discharge mode, when the first and second alignment units are moved in the shift direction to align the second and subsequent sheet bundles at the first and second alignment units and lowered from the retracted position to the alignment-possible position, the sheet loading device according to claim 7 is characterized in that, while lowering the first and second alignment units from the retracted position to the alignment-possible position, the alignment units are decelerated to the second speed before contacting the upper surface of the first bundle of already loaded sheets loaded on the loading tray, and then lowered again at the third speed.

9. The sheet loading device according to claim 7, characterized in that, in the shift discharge mode and the straight discharge mode in which a sheet is discharged onto the loading tray without shifting the sheet by the shift unit, when there is no sheet on the loading tray, the control unit lowers the first alignment unit and the second alignment unit from the retracted position to the alignment-possible position, decelerating the first alignment unit and the second alignment unit to the second speed before the alignment unit contacts the loading tray while lowering them from the retracted position to the alignment-possible position, and then lowering them again at the third speed.

10. An image forming unit that forms an image on a sheet, A conveying unit that conveys the sheet on which the image has been formed in the image forming unit in the conveying direction, A shifting unit that shifts the sheet conveyed by the conveying unit in a sheet width direction intersecting the conveying direction, A loading tray for loading the sheets, A discharge unit that discharges sheets toward the aforementioned loading tray, A first alignment part and a second alignment part that act on both ends in the width direction of the sheet bundle loaded on the aforementioned loading tray to align the sheet bundle, The first alignment unit and the second alignment unit are set up in a retracted position above the sheet that is shifted by the shift unit and discharged by the discharge unit, and a lifting mechanism is provided to raise and lower the sheet that has been discharged onto the loading tray to an alignment position where it can be aligned. A moving mechanism for moving the first alignment section and the second alignment section in the sheet width direction, The system comprises a control unit that controls the lifting mechanism and the moving mechanism, In the shift discharge mode in which the shift unit shifts and discharges sheets onto the loading tray, the control unit moves the first and second alignment units in the shift direction to align the second and subsequent sheet bundles with the first and second alignment units, and lowers them from the retracted position to the alignment-possible position, An image forming system characterized in that, of the first and second alignment sections, at least the alignment section located on the upstream side in the shift direction is decelerated from a first speed to a second speed before contacting the upper surface of the first bundle of already stacked sheets loaded on the loading tray while being lowered from the retracted position to the alignment-possible position, and then lowered again at a third speed that is slower than the first speed and faster than the second speed, thereby contacting the upper surface of the already stacked sheets.

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