Stacking device

Abstract

To make it easier to align the edges of stacked sheets in stacking technology where sheets are dropped and stacked.SOLUTION: A stacking device stacks sheets by dropping them one by one in order and includes a discharge device, a reception device, and a movement prevention part. The discharge device discharges a sheet into a drop space where the sheet is dropped. The reception device includes a reception part that receives the sheet that has been discharged from the discharge device in the drop space and can move the reception part back and forth between a forward position where it has advanced into the drop space and a backward position where it has retreated from the drop space. When the reception part moves back from the forward position to the backward position in a state where the sheet is received by the reception part, the movement prevention part prevents an accompanying movement of the sheet at a predetermined position in the drop space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a stacking technique for stacking sheets. [Background technology]

[0002] As a stacking technology for stacking sheets, for example, Patent Document 1 discloses a technology in which sheets of a predetermined length are treated as sheets and the sheets are discharged one by one from discharge rollers to be stacked on a pallet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-246118 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the sheet discharged from the discharge rollers is dropped directly onto the pallet. However, the posture of the sheet is not necessarily stable when discharged from the discharge rollers, and it cannot be said that all sheets will have the same posture. For this reason, the edges of the sheets stacked on the pallet are unlikely to be aligned, and therefore, after the sheets are stacked on the pallet, it is necessary to realign the edges of the sheets.

[0005] This situation is likely to occur when the objects to be stacked are sheet-like objects (including bag-like objects folded into sheets) and the objects are made of a light or soft material, or a material that is easily charged with static electricity. Specifically, when the objects are made of a light or soft material, they are likely to become distorted and misaligned due to air resistance when falling. In addition, when the objects are made of a material that is easily charged with static electricity, the static electricity tends to cause them to stick to walls and other surfaces, making stacking itself difficult.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to make it easier to align the edges of stacked sheets in a stacking technique in which sheets are dropped and stacked. [Means for solving the problem]

[0007] The stacking device according to the present invention is a stacking device that stacks sheets by dropping them one by one in order, and includes a discharge device, a receiving device, and a movement prevention unit. The discharge device discharges the sheets into a falling space into which the sheets fall. The receiving device includes a receiving unit that receives the sheets discharged from the discharge device in the falling space, and is capable of moving the receiving unit back and forth between an advanced position where the receiving unit advances into the falling space and a retreated position where the receiving unit retreats from the falling space. When the receiving unit retreats from the advanced position to the retreated position after receiving the sheets, the movement prevention unit prevents the associated movement of the sheets at a predetermined position in the falling space (mode 1).

[0008] According to the stacking device, the sheet discharged from the discharge device can be temporarily received by the receiving section, so that even if the sheet is displaced when discharged from the discharge device, the disturbed position can be restored on the receiving section. Also, when the receiving section retracts to the retracted position, the associated movement of the sheet can be prevented by the movement prevention section, so that the sheet can be kept in the falling space and the edge of the sheet can be aligned to a predetermined position. This makes it possible to resume the fall of the sheet once received by the receiving section in the falling space with the edge aligned to a predetermined position.

[0009] In the stacking device according to the above aspect 1, the movement preventing portion may have an end face facing in the same direction as the advancing direction of the receiving portion, and may be arranged so that when viewed from a lateral direction perpendicular to the advancing direction, the end face intersects with the receiving portion at the above-mentioned predetermined position when the receiving portion retreats from the advanced position to the retreated position (aspect 2).As a more specific configuration, in the stacking device according to the above aspect 2, the receiving portion may include at least two arm portions extending in the advancing direction and arranged spaced apart from each other in the lateral direction, and the movement preventing portion may be arranged at a position between the two adjacent arm portions (aspect 3).

[0010] According to the above-mentioned aspects 2 or 3, with a simple configuration that utilizes the advancing and retreating movement of the receiving part, it is possible to stack the leaves with their edges always aligned in the same position (predetermined position) when the leaves are dropped.

[0011] In the stacking device according to any one of the above aspects 1 to 3, the receiving device may be disposed so that the advancing direction of the receiving portion is the same as the discharge direction of the sheets from the discharge device (aspect 4).

[0012] According to the above-mentioned fourth aspect, the retracted position of the receiving section can be set to a position below the discharge device. In other words, the receiving section can be retracted from a position in the drop space to a position below the discharge device. Therefore, it is possible to install the receiving device in the stacking device without increasing the size of the stacking device.

[0013] The stacking device of the above-mentioned aspect 4 may further include a control device, which may cause the receiving device to move (advance) the receiving section from the retracted position to the advanced position in parallel with the discharge of the sheet each time the sheet is discharged from the discharge device (aspect 5).

[0014] According to the above-mentioned aspect 5, the relative speed between the receiving section and the sheet when the sheet is received by the receiving section can be reduced. This makes it possible to create a state in which the sheet is gently placed on the receiving section from above. As a result, it is possible to suppress disturbance of the sheet when it is discharged.

[0015] In the stacking device of the above-mentioned aspect 5, when the control device causes the receiving device to move (advance) the receiving section from a retracted position to an advanced position, the control device may cause the receiving device to move the receiving section so that the advance speed of the receiving section at that time is the same as the discharge speed of the sheet material from the discharge device (aspect 6).

[0016] According to the sixth aspect, the relative speed can be made close to zero, which makes it possible to create a state in which the sheet is gently placed on the receiving part that is completely stationary. As a result, disturbance of the sheet during ejection can be easily suppressed.

[0017] The stacking device according to the above-mentioned aspect 5 or 6 may further include a stacking table and a lifting device for lifting and lowering the stacking table (aspect 7). Alternatively, the stacking device according to any of the above-mentioned aspects 1 to 4 may further include a stacking table, a lifting device for lifting and lowering the stacking table, and a control device (aspect 8). Here, the stacking table is a table on which the sheets received by the receiving section fall and are stacked when the receiving section retreats to the retreated position. The control device may cause the lifting device to execute the lowering of the stacking table in response to a change in the fall distance from the state in which the stacking table is raised by the lifting device to the topmost sheet among the sheets being stacked on the stacking table.

[0018] According to the above-mentioned aspects 7 and 8, it is possible to adjust the height position of the stacking table so that the falling distance of the sheet from the receiving section is always constant or within a predetermined range. This makes it possible to make the falling distance of all the sheets to be stacked as uniform as possible. Therefore, it is possible to make the falling state of the sheets as uniform as possible, and as a result, it is possible to suppress the positional deviation between the sheets when stacking them. Effect of the Invention

[0019] According to the present invention, in a stacking technique in which sheets are dropped and stacked, the edges of the stacked sheets are more likely to be aligned. [Brief description of the drawings]

[0020] [Figure 1] 1 is a front view conceptually showing a stacking device according to an embodiment of the present invention. [Diagram 2] 1 is a block diagram conceptually illustrating a stacking device according to an embodiment. [Diagram 3] FIG. 2 is a perspective view showing the main components of a stacking device. [Figure 4] 4 is a flowchart showing a control process executed by a control device included in the stacking device. [Figure 5A] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5B] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5C] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5D] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5E] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5F] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5G] 4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 5H]4A to 4C are conceptual diagrams sequentially illustrating the operation of the stacking device. [Figure 6] FIG. 2 is a perspective view showing the main parts of the configuration of a stacking device according to a first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] [1] Configuration of stacking device FIG. 1(A) and FIG. 1(B) are front views conceptually showing a stacking device according to an embodiment, and FIG. 2 is a block diagram conceptually showing the stacking device. FIG. 3 is a perspective view showing the main parts of the configuration of the stacking device. The stacking device of this embodiment is a device that stacks a plurality of sheets Q by dropping them one by one in order. Here, the sheets Q to be stacked are sheet-shaped sheets Q (including those folded into sheets from bag-shaped sheets). As shown in FIG. 1(A) and FIG. 2, the stacking device includes a discharge device 1, a stacking table 2, a lifting device 3, a receiving device 4, a movement prevention unit 5, and a control device 6. The configuration of each unit will be specifically described below.

[0022] [1-1] Discharge device The discharge device 1 includes a transport section 11 that transports the sheet Q, and a discharge section 12 that discharges the sheet Q from a terminal position of transport by the transport section 11 (see FIG. 1(A) and FIG. 3).

[0023] Specifically, the discharge unit 12 includes a rotating roller 121, a nip roller 122 (driven roller) disposed above the rotating roller 121, and a drive unit 123 that enables the up and down movement of the nip roller 122. The drive unit 123 lowers the nip roller 122, thereby pressing the nip roller 122 against the rotating roller 121 from above.

[0024] Therefore, the discharge section 12 can nip the leaf Q at the terminal position of the conveyance section 11 by sandwiching the leaf Q between the rotating roller 121 and the nip roller 122. Furthermore, the discharge section 12 can discharge the leaf Q from the terminal position by sending out the leaf Q by the rotation of the rotating roller 121 while keeping the leaf Q nipped (see Figs. 5A to 5D). At this time, the leaf Q is pressed against the rotating roller 121 by the nip of the nip roller 122, so that the rotation of the rotating roller 121 is easily transmitted to the leaf Q. Therefore, the leaf Q is discharged at a speed corresponding to the rotation speed of the rotating roller 121.

[0025] Then, the sheet Q discharged from the discharge section 12 falls into a space on the opposite side of the discharge section 12 from the conveying section 11. In this embodiment, this space is used as a fall space Sf (see FIG. 1(A)) into which the sheet Q falls so that the sheet Q can be stacked.

[0026] In this embodiment, the discharge device 1 further includes a static elimination unit 13 that removes static electricity from the sheet Q (see FIG. 1(A)). Specifically, the static elimination unit 13 is disposed so as to be able to eliminate static electricity from the portion of the sheet Q that is sent from the discharge unit 12 to the drop space Sf. If the sheet Q is made of a material that does not retain static electricity, the discharge device 1 may be appropriately modified to a configuration without the static elimination unit 13.

[0027] [1-2] Stacking platform and lifting device The stacking table 2 is disposed in the fall space Sf. The sheets Q discharged from the discharge device 1 are stacked on the stacking table 2. In this embodiment, the stacking table 2 is a cart equipped with casters, and can be carried into and out of the fall space Sf (see FIG. 1(A)). In addition, in the fall space Sf, the stacking table 2 can be raised and lowered by the lifting device 3 (see FIG. 1(B)).

[0028] Specifically, the lifting device 3 includes an arm section 31 that supports the stacking table 2 from below, and a drive section 32 that enables the arm section 31 to be raised and lowered. The lifting device 3 is controlled by a control device 6, which will be described later, and is therefore capable of adjusting the height position of the arm section 31 (in other words, the height position of the stacking table 2 supported by the arm section 31) in addition to raising and lowering the stacking table 2.

[0029] Such a lifting device 3 can shorten the fall distance of the sheets Q to the stacking table 2 in the fall space Sf by raising the stacking table 2 (see FIG. 1(B)). Also, as described later, it becomes possible to adjust the height position of the stacking table 2 in response to the change in the fall distance that occurs as the sheets Q are stacked on the stacking table 2.

[0030] Then, after stacking of the sheets Q on the stacking table 2 in the fall space Sf is completed, the stacking table 2 is lowered and then removed from the fall space Sf, whereby the sheets Q stacked on the stacking table 2 can be moved from the fall space Sf to another location in that state.

[0031] In this embodiment, the stacking table 2 is provided with a jump-out prevention section 21 (see Fig. 1(B) and Fig. 3). Here, the jump-out prevention section 21 is configured to prevent the passage of the sheet Q when the sheet Q discharged from the discharge device 1 is about to pass through the fall space Sf on the stacking table 2 due to inertia. In this embodiment, the jump-out prevention section 21 is a plate erected on the upper surface of the stacking table 2 (the surface on which the sheet Q is stacked), and is configured to face the discharge device 1 via the fall space Sf when the stacking table 2 is raised by the lifting device 3.

[0032] Such a jump-out prevention unit 21 allows the sheet materials Q discharged from the discharge device 1 to always fall within the fall space Sf. The jump-out prevention unit 21 may be permanently installed at a position facing the discharge device 1 across the fall space Sf. In addition, when there is no risk of the sheet materials Q discharged from the discharge device 1 jumping out of the fall space Sf (for example, when the sheet materials Q can be reliably received by the receiving section 41 of the receiving device 4 described later), the stacking device may be appropriately modified to a configuration without the jump-out prevention unit 21.

[0033] [1-3] Receiving device The receiving device 4 is a device that receives the sheet Q discharged from the discharging device 1 in the middle of its fall in the fall space Sf, and includes a receiving section 41 that receives the sheet Q in the fall space Sf, and a drive section 42 that enables the receiving section 41 to move back and forth between an advance position P1 and a retreat position P2 (see FIG. 1(A)). Here, the advance position P1 is the position of the receiving section 41 when it advances into the fall space Sf (the position of the receiving section 41 shown in FIG. 5D), and is set so that the sheet Q discharged from the discharging device 1 can be received in the middle of its fall in the fall space Sf. The retreat position P2 is the position of the receiving section 41 when it retreats from the fall space Sf (the position of the receiving section 41 shown in FIG. 5G), and is set so that the sheet Q received at the advance position P1 can be dropped again.

[0034] In this embodiment, the receiving portion 41 includes two arms 41X extending in the advancing direction Dx from the retreat position P2 to the advancing position P1 (see FIG. 3), and the two arms 41X are arranged apart from each other in the lateral direction Dy perpendicular to the advancing direction Dx. The upper surfaces of the arms 41X form a receiving surface 41r that receives the sheet Q.

[0035] With such a receiving device 4, the sheet material Q discharged from the discharging device 1 can be temporarily received at the receiving section 41 (see Figures 3 and 5D), so that even if the posture of the sheet material Q is disturbed when it is discharged from the discharging device 1, the disturbed posture can be restored on the receiving section 41.

[0036] <Positional relationship with the discharge device> In this embodiment, the receiving device 4 is disposed relative to the discharge device 1 such that the advancing direction Dx of the receiving section 41 is the same as the discharge direction Dt of the sheet material Q from the discharge device 1 (see Figs. 1(A) and 3). With this arrangement, as shown in Fig. 1(A), the retracted position P2 of the receiving section 41 can be set to a position below the discharge device 1. In other words, it becomes possible to retract the receiving section 41 from a position within the drop space Sf to below the discharge device 1. Therefore, it becomes possible to install the receiving device 4 in the stacking device without increasing the size of the stacking device.

[0037] <Positional relationship with the jump-out prevention part> In this embodiment, the receiving device 4 is configured in relation to the anti-jump-out portion 21 such that when the receiving portion 41 advances to the advance position P1, the two adjacent arm portions 41X reach positions on either side of the anti-jump-out portion 21 (see FIG. 3).

[0038] [1-4] Movement prevention part The movement prevention section 5 is configured to prevent the associated movement of the sheet Q at a predetermined position Px in the drop space Sf when the receiving section 41 receives the sheet Q and retreats from the advance position P1 to the retreat position P2 (see Figures 3, 5D to 5F).

[0039] Specifically, the movement preventing portion 5 has an end surface 50s facing the same direction as the advancing direction Dx (see FIG. 3). The movement preventing portion 5 is disposed such that, when viewed from the lateral direction Dy (see FIG. 5D), the end surface 50s intersects with the receiving portion 41 at a predetermined position Px when the movement preventing portion 5 has retreated from the advancing position P1 to the retreating position P2.

[0040] In this embodiment, the movement prevention portion 5 is a plate installed between two adjacent arm portions 41X, and is arranged so that one surface of the plate becomes an end surface 50s (see FIG. 3). In this embodiment, the movement prevention portion 5 (plate) is also installed on both sides of the two arm portions 41X.

[0041] According to such a movement prevention unit 5, when the receiving unit 41 retreats to the retreat position P2, the movement of the sheet Q accompanying the retreat can be prevented by the movement prevention unit 5 (see FIG. 5E and FIG. 5F), so that the sheet Q can be kept in the falling space Sf and the edge position of the sheet Q can be aligned to the predetermined position Px. This makes it possible to resume the fall of the sheet Q once received by the receiving unit 41 in the falling space Sf with the edge position aligned to the predetermined position Px. Then, the sheet Q that has fallen in such a state is stacked on the stacking table 2, so that the edges of the stacked sheet Q are easily aligned. In other words, it is possible to create a state in which the sheet Q is neatly stacked on the stacking table 2.

[0042] Furthermore, according to the configuration of the movement preventing section 5 in which the end face 50s intersects with the receiving surface 41r, with a simple configuration that utilizes the forward and backward movement of the receiving section 41, when the sheets Q are dropped, it is possible to stack the sheets Q with their ends always aligned in the same position (predetermined position Px).

[0043] [1-5] Control device The control device 6 includes a storage unit 61 and a control unit 62 (see FIG. 2). The storage unit 61 is a unit that stores information required for controlling the stacking device (such as parameters required for controlling the discharge device 1, the lifting device 3, and the receiving device 4), and is composed of storage devices such as ROM and RAM. The control unit 62 is a unit that executes control of the stacking device, and is composed of a processing device such as a CPU. The control processing executed by the control device 6 in the stacking device will be specifically described below.

[0044] Fig. 4 is a flow chart showing the control process executed by the control device 6. Figs. 5A to 5H are conceptual diagrams sequentially showing the operations of the stacking device caused by the control process. Fig. 4 shows the flow from the point when the lifting device 3 raises the stacking table 2 to a predetermined height position in the drop space Sf and the transport unit 11 starts transporting the sheet material Q.

[0045] The control device 6 first judges whether the sheet Q conveyed by the conveying section 11 has reached the terminal position (the nip position by the discharge section 12) (step S100). Specifically, a detection sensor (not shown) is provided that can detect the sheet Q when it reaches the terminal position, and the control device 6 judges whether the detection sensor has transitioned from an undetected state to a detected state based on the detection result of the detection sensor. In this way, when the control device 6 can judge that the sheet Q has "transitioned (Yes)" to the detected state, it can judge that the sheet Q has "reached (Yes)" the terminal position based on that judgment.

[0046] The control device 6 repeatedly executes step S100 until it can determine that "it has reached (Yes)" in step S100. Then, when the control device 6 can determine that "it has reached (Yes)" in step S100, it controls the discharge section 12 to cause the discharge section 12 to start nipping the sheet Q with the nip roller 122 (step S101, see FIG. 5A). Meanwhile, in this embodiment, the rotating roller 121 is maintained in a rotating state at all times. Therefore, the nipping of the sheet Q transmits the rotation of the rotating roller 121 to the sheet Q, and as a result, the sheet Q is sent out at a speed corresponding to the rotation speed of the rotating roller 121 and discharged from the discharge section 12.

[0047] Furthermore, in step S101, the control device 6 not only causes the discharge section 12 to start nipping the sheet Q, but also controls the receiving device 4 to start advancing the receiving section 41 from the retracted position P2 toward the advancing position P1. According to the process of step S101, every time a sheet Q is discharged from the discharge device 1, the movement (advancement) of the receiving section 41 from the retracted position P2 to the advancing position P1 is executed in parallel with the discharge of the sheet Q.

[0048] Here, in this embodiment, the receiving device 4 is disposed relative to the discharge device 1 such that the advancing direction Dx of the receiving section 41 is the same as the discharging direction Dt of the sheet Q from the discharge device 1. Therefore, by moving the receiving section 41 toward the advancing position P1 in parallel with the discharging of the sheet Q, the relative speed between the receiving section 41 and the sheet Q when the receiving section 41 receives the sheet Q can be reduced. This makes it possible to create a state in which the sheet Q is gently placed on the receiving section 41 from above (see Figs. 5B to 5D). As a result, it is possible to suppress disturbance of the sheet Q when it is discharged.

[0049] In this embodiment, when the control device 6 causes the receiving device 4 to move (advance) the receiving section 41 from the retracted position P2 to the advanced position P1 in step S101, the control device 6 causes the receiving device 4 to move (advance) the receiving section 41 so that the advanced speed Vx of the receiving section 41 at that time is the same as the discharge speed Vt of the sheet Q from the discharge device 1 (see Figures 5B to 5D).

[0050] Therefore, in this embodiment, the above-mentioned relative speed can be made close to zero, which makes it possible to create a state in which the sheet Q is gently placed from above on the receiving section 41 that has completely stopped. As a result, disturbance of the sheet Q during discharge can be easily suppressed.

[0051] After step S101, the control device 6 judges whether or not the discharge of the sheet Q from the discharge unit 12 has been completed (step S102). Specifically, the control device 6 judges whether or not the detection sensor has transitioned from a detection state to an undetected state based on the detection result of the above-mentioned detection sensor (not shown). In this way, when the control device 6 can determine that the detection sensor has "transitioned (Yes)" to an undetected state, it can determine that the discharge of the sheet Q has "been completed (Yes)" based on that judgment.

[0052] The control device 6 repeatedly executes step S102 until it can determine that the process is "completed (Yes)" in step S102. When it can determine that the process is "completed (Yes)" in step S102, the control device 6 controls the discharge unit 12 to raise the nip roller 122 (step S103. See FIG. 5D).

[0053] After step S103, the control device 6 controls the receiving device 4 to start retracting the receiving unit 41 from the advancing position P1 toward the retreating position P2 after the receiving unit 41 reaches the advancing position P1 (step S104). Specifically, the control device 6 determines whether the receiving unit 41 has reached the advancing position P1 (step S104A), and if it is determined that the receiving unit 41 has reached the advancing position P1 (Yes), it causes the receiving device 4 to start retracting the receiving unit 41 from the advancing position P1 (step S104B).

[0054] According to the process of step S104, the receiving section 41, having received the sheet Q, moves in the opposite direction to the advancing direction Dx toward the retreat position P2. With this movement, the sheet Q on the receiving section 41 also moves in the same direction. The movement of the sheet Q is stopped halfway (specifically, at a predetermined position Px in the falling space Sf) by the sheet Q abutting against the movement stopper 5 (see FIG. 5E). As a result, the sheet Q remains in the falling space Sf with its edge aligned to the predetermined position Px. Meanwhile, the movement (retraction) of the receiving section 41 toward the retreat position P2 continues, so that the receiving section 41 retreats from under the sheet Q (see FIG. 5F). As a result, the fall of the sheet Q once received by the receiving section 41 in the falling space Sf is resumed with its edge aligned to the predetermined position Px. More specifically, the receiving portion 41 gradually retreats from under the sheet Q, whereby the sheet Q falls successively from its leading end side in the advancing direction Dx.

[0055] And, the leaf material Q that falls in such a state is likely to fall straight down towards the stacking table 2 (see FIG. 5G). At this time, the leaf material Q lands in order from the leading edge (see FIG. 5F), so it can land while pushing out the air between it and the stacking table 2 (or the leaf material Q already stacked there). Therefore, it is possible to suppress the positional shift of the leaf material Q itself that may occur when the leaf material Q lands on the stacking table 2 (see FIG. 5G).

[0056] Therefore, by repeatedly executing the above steps S100 to S104, it becomes possible to stack the sheets Q on the stacking table 2 with their edges aligned (see FIG. 5H). In other words, it becomes possible to create a state in which the sheets Q are neatly stacked on the stacking table 2.

[0057] In this embodiment, the above steps S100 to S104 are repeatedly executed until a predetermined number of sheets Q are stacked on the stacking table 2. Specifically, the control device 6 counts the number of executions (repetitions) of steps S100 to S104 to count the number of sheets Q stacked on the stacking table 2 (step S105). In addition, every time steps S100 to S104 are executed, the control device 6 judges whether the number of sheets Q counted in step S105 has reached a predetermined number Nt (step S106). Then, when the control device 6 judges that the number has been reached (Yes) in step S106, it ends the control process. On the other hand, when the control device 6 judges that the number has not been reached (No) in step S106, it performs the process described below, returns to step S100, and executes the process from step S100 again.

[0058] In this embodiment, the height position of the stacking table 2 is adjusted according to the change in the fall distance Lf caused by the sheet Q being stacked on the stacking table 2 so that the fall distance Lf (see Figs. 5F and 5H) of the sheet Q from the receiving section 41 is always within a predetermined range Rd (a range from a lower limit Rd1 to an upper limit Rd2). Here, the fall distance Lf is the vertical distance from the position of the sheet Q when it is received by the receiving section 41 to the topmost sheet Q among the sheets Q stacked on the stacking table 2. Also, this fall distance Lf is calculated based on the detection result of a distance sensor (not shown) provided above the stacking table 2, as an example.

[0059] In this way, by adjusting the height position of the stacking table 2 so that the fall distance Lf of the sheet Q falls within the predetermined range Rd, it is possible to make the fall distance Lf as uniform as possible for all the sheets Q to be stacked. Therefore, the fall state of the sheets Q can be made as uniform as possible, and as a result, it is possible to suppress the positional deviation between the sheets Q when stacking them.

[0060] Specifically, when the control device 6 judges that the fall distance Lf at that time is within the predetermined range Rd (Rd1≦Lf≦Rd2) before returning to step S100 (step S107). When the control device 6 judges that the fall distance Lf is within the predetermined range Rd (Yes) in step S107, it can determine that there is no need to adjust the height position of the stacking platform 2. In this case, the control device 6 returns to step S100 without adjusting the height position. On the other hand, when the control device 6 judges that the fall distance Lf is not within the predetermined range Rd (No) in step S107, it can determine that there is a need to adjust the height position of the stacking platform 2. In this case, the control device 6 adjusts the height position of the stacking platform 2 by having the lifting device 3 lower the stacking platform 2 so that the fall distance Lf is within the predetermined range Rd (step S108).

[0061] In steps S107 and S108, the width of the predetermined range Rd, which is the criterion for judgment in step S107, is set small, thereby making it possible to reduce the variation in the fall distance Lf that occurs between one adjustment of the height position of the stacking table 2 and the next adjustment (the variation in the fall distance Lf that occurs as the sheets Q are stacked during that time). This makes it possible to adjust the height position of the stacking table 2 so that the fall distance Lf is always constant.

[0062] After the above control process (stacking the sheets Q on the stacking table 2) is completed, the stacking table 2 is lowered and then removed from the drop space Sf, so that the sheets Q stacked on the stacking table 2 can be moved from the drop space Sf to another location in their original state (i.e., with their edges still aligned).

[0063] [2] Variations [2-1] First modified example 6 is a perspective view showing the main components of the stacking device according to the first modified example. As shown in this figure, the movement prevention portion 5 may be formed of a portion of a wall 51 having two through holes 51a through which the two arms 41X of the receiving portion 41 pass (specifically, a portion between the two through holes 51a or portions on both sides of the two through holes 51a).

[0064] Furthermore, in the stacking device described above, the receiving unit 41 is not limited to being configured with two arm units 41X, and may be appropriately changed to being configured with only one arm unit 41X or being configured with three or more arm units 41X. Even in these configurations, the movement prevention unit 5 may be disposed between two adjacent arm units 41X or at positions on both sides of the receiving unit 41, as long as it is a position where the movement of the sheet Q can be prevented.

[0065] [2-2] Second variant In the above-mentioned stacking device, the control device 6 may be appropriately modified to perform control processing such as advancing the receiving section 41 to the advance position P1 and waiting (stopping) it before discharging the sheet Q, receiving the sheet Q discharged from the discharge device 1 in that state at the receiving section 41, and then retreating the receiving section 41 to the retreat position P2.

[0066] In this case, the receiving device 4 is not limited to being arranged so that the advancing direction Dx of the receiving section 41 is the same as the discharging direction Dt of the sheet Q, but may be arranged so that the advancing direction Dx is opposite to the discharging direction Dt (so that the receiving section 41 advances from the opposite side of the discharging section 12 with respect to the falling space Sf) or so that the advancing direction Dx is perpendicular to the discharging direction Dt (so that the receiving section 41 advances from either the left or right side with respect to the falling space Sf). When the arrangement of the receiving device 4 is changed, the position of the movement prevention section 5 is also changed accordingly.

[0067] [2-3] Other variations In the stacking device described above, the discharge device 1 may be appropriately changed to one configured to discharge the sheets Q directly from the transport section 11 to the drop space Sf (in other words, a configuration without the discharge section 12).

[0068] The above-mentioned stacking device may be appropriately modified to a device configured to stack the sheets Q without changing the height position of the stacking table 2. In this case, the stacking device may be appropriately modified to a configuration without the lifting device 3.

[0069] The above-described stacking device may be modified as appropriate to one configured to intentionally bring the sheets Q discharged from the discharge device 1 into contact with the jump-out prevention portion 21.

[0070] The above-mentioned embodiments and the description of the modifications should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above-mentioned embodiments and modifications. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0071] 1 Ejection device 2 Stacking table 3 Lifting device 4 Receiving device 5 Movement prevention part 6. Control device Q sheeted body 11 Conveyor section 12 Discharge section 13 Static electricity removal section 21 Protrusion prevention part 31 Arm section 32 Drive unit 41 Receiving Department 41X Arm part 41r Receiving surface 42 Drive unit 50s end face 51 Wall 51a Through hole 61 Storage section 62 Control section Dt Discharge direction Dx advance direction Dy Horizontal Lf Fall distance Nt: Predetermined number P1 advance position P2 Retract position Px in place Rd Predetermined range SF falling space Vt discharge speed Vx advance speed 121 Rotating roller 122 Nip roller 123 Drive unit Rd1 Lower limit Rd2 Upper limit

Claims

1. This is a stacking device that drops and stacks the sheets one by one. a discharge device that discharges the sheet into a falling space into which the sheet falls; a receiving device including a receiving section that receives the sheet discharged from the discharge device in the falling space, the receiving section being capable of reciprocating between an advanced position where the receiving section is advanced into the falling space and a retreated position where the receiving section is retreated from the falling space; a movement prevention part that prevents the movement of the sheet at a predetermined position within the falling space when the receiving part receives the sheet and retreats from the advanced position to the retreated position; A stacking device comprising:

2. The stacking device of claim 1, wherein the movement preventing portion has an end face facing in the same direction as the advancing direction of the receiving portion, and when viewed from a horizontal direction perpendicular to the advancing direction, the end face is positioned so as to intersect with the receiving portion at the specified position when the receiving portion retreats from the advanced position to the retreated position.

3. The receiving portion includes at least two arm portions extending in the advancing direction and arranged at a distance from each other in the lateral direction, The stacking device according to claim 2 , wherein the movement preventing portion is disposed at a position between the two adjacent arm portions.

4. 4. The stacking apparatus according to claim 1, wherein the receiving device is disposed so that the direction of advancement of the receiving portion is the same as the direction of discharge of the sheet material from the discharge device.

5. The stacking device according to claim 4, further comprising a control device that causes the receiving device to move the receiving section from the retreated position to the advanced position in parallel with the discharge of the sheet each time the sheet is discharged from the discharge device.

6. The stacking device of claim 5, wherein when the control device causes the receiving device to move the receiving section from the retracted position to the advanced position, the control device causes the receiving device to move the receiving section so that the advanced speed of the receiving section at that time is the same as the discharge speed of the sheet material from the discharge device.

7. a stacking table onto which the sheets received by the receiving section fall and are stacked when the receiving section retreats to the retreated position; A lifting device for lifting and lowering the stacking table; Further comprising: The stacking device described in claim 5, wherein the control device causes the lifting device to lower the stacking table in accordance with a change in the fall distance from a state in which the stacking table is raised by the lifting device to the topmost sheet among the sheets being stacked on the stacking table.

8. a stacking table onto which the sheets received by the receiving section fall and are stacked when the receiving section retreats to the retreated position; A lifting device for lifting and lowering the stacking table; a control device that causes the lifting device to lower the stacking table in response to a change in a fall distance from a state in which the stacking table is raised by the lifting device to a topmost sheet among the sheets being stacked on the stacking table; The stacking device according to any one of claims 1 to 3, further comprising:

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