CN111056355A

CN111056355A - Sheet stacking apparatus and image forming system

Info

Publication number: CN111056355A
Application number: CN201910972764.XA
Authority: CN
Inventors: 片桐达矢
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 2018-10-17
Filing date: 2019-10-14
Publication date: 2020-04-24
Anticipated expiration: 2039-10-14
Also published as: CN111056355B; US20200122952A1; JP2020063122A

Abstract

The invention provides a sheet stacking apparatus and an image forming system, which can inhibit the generation of downtime. The first tray (21) and the second tray (25) have at least three operating states as their operating states. Specifically, the first operating state is an operating state in which the first tray (21) is at a sheet stacking position at which sheets (P) discharged from the sheet discharge unit (20) are stacked, and the second tray (25) is located below the first tray (21). The second operating state is an operating state in which the upper surface (25a) of the second tray (25) is positioned above the upper surface (21a) of the first tray (21) and the sheets P stacked on the first tray (21) can be delivered to the second tray (25). The third operating state is an operating state in which the first tray (21) that delivered the sheet (P) to the second tray (25) is returned to the sheet stacking position.

Description

Sheet stacking apparatus and image forming system

Technical Field

The invention relates to a sheet stacking apparatus and an image forming system.

Background

Conventionally, a sheet stacking apparatus that stacks a large number of sheets supplied from outside the apparatus has been known. In such a sheet stacking apparatus, the following structure is known: the paper delivery device is provided with a tray for stacking paper and a transport vehicle capable of transporting the paper to the outside of the device, and can deliver the paper to the transport vehicle by each tray. According to this configuration, when the sheet is conveyed to the outside of the apparatus by the conveyance vehicle, the sheet can be delivered to the conveyance vehicle together with the tray, and therefore, a large number of stacked sheets can be easily handled.

For example, patent document 1 discloses a sheet stacking apparatus (sheet stacking apparatus) having: a tray lifting member; a tray mechanism which is detachably attached to the tray lifting member and stacks sheets (sheets) from the sheet discharge port; a driving mechanism which enables the tray lifting component to lift up and down below the paper discharging port; a control mechanism of the drive mechanism; and a carrying mechanism for mounting the tray mechanism separated from the tray lifting component and conveying the tray mechanism to the outside of the device. In this case, the tray lifting member and the carrying mechanism are configured to be transferred to and mounted on each other at a mounting and dismounting position after the lowering of the tray lifting member.

Patent document 1: japanese patent laid-open No. 2008-94581

However, according to the method disclosed in patent document 1, a configuration is adopted in which the sheet is delivered to the transport vehicle together with the tray. Therefore, there is a problem that the discharge of the paper sheet must be stopped during the period from the time when the tray inside the apparatus is delivered to the transport vehicle to the time when the tray is returned to the inside of the apparatus, and a downtime occurs.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a sheet stacking apparatus and an image forming system capable of suppressing occurrence of downtime.

In order to solve this problem, the sheet stacking apparatus of the present invention includes: a first tray that stacks sheets; a paper discharge unit that discharges paper supplied from outside the apparatus to a first tray; a second tray that receives the sheets stacked on the first tray and discharges the received sheets to the outside of the apparatus; a control unit for controlling the operating states of the first tray and the second tray; the first tray and the second tray have a first operating state in which the first tray is at a sheet stacking position at which sheets discharged from the sheet discharge unit are stacked and the second tray is positioned below the first tray, a second operating state in which the upper surface of the second tray is positioned above the upper surface of the first tray and the sheets stacked on the first tray can be delivered to the second tray, and a third operating state in which the first tray to which the sheets have been delivered to the second tray is returned to the sheet stacking position.

Here, in the present invention, it is preferable that the first tray and the second tray have a gap for passing the other tray so that the trays do not interfere with each other on the same plane.

In the present invention, it is preferable that the first tray is moved to reach a sheet delivery position corresponding to the height of the second tray, and thereby the first operating state is changed to the second operating state.

In the present invention, it is preferable that the second tray is positioned below the first tray in the first operating state, and the first tray is lowered to shift from the first operating state to the second operating state.

In the present invention, it is preferable that a plurality of second trays are stacked in the vertical direction, and the paper delivery position is switched according to the height of the second tray located at the uppermost layer.

Preferably, the present invention further includes a base portion that moves between the inside and the outside of the apparatus, and the second tray is mounted on the base portion.

In the present invention, it is preferable that the second tray is detachably mounted on the pedestal portion.

Preferably, the present invention further includes a transport vehicle on which the second tray is mounted and which transports the second tray, and the transport vehicle is configured to be able to be housed inside the apparatus.

Preferably, the present invention further includes a transport vehicle that carries a second tray discharged outside the machine and transports the second tray.

In the present invention, it is preferable that the second tray is moved to reach a sheet delivery position corresponding to the height of the first tray, thereby making a transition from the first operating state to the second operating state.

In the present invention, it is preferable that the first tray and the second tray are moved to reach a predetermined sheet delivery position, respectively, to shift from the first operating state to the second operating state.

The image forming system of the present invention includes an image forming apparatus that discharges a sheet on which an image is formed, and the sheet stacking apparatus that stacks the sheet discharged from the image forming apparatus.

According to the sheet stacking apparatus and the image forming system of the present invention, the occurrence of downtime can be suppressed.

Drawings

Fig. 1 is a front view schematically showing the configuration of an image forming system according to a first embodiment.

Fig. 2 is a configuration diagram showing a main part of the sheet stacking apparatus mainly including a first tray and a second tray.

Fig. 3 is an explanatory diagram showing a relationship between the second tray and the first tray.

Fig. 4 is a flowchart showing an operation flow of the image forming system.

Fig. 5 is an explanatory diagram illustrating the flow of the operation of the sheet stacking apparatus.

Fig. 6 is an explanatory diagram showing a configuration of a sheet stacking apparatus according to a second embodiment.

Fig. 7 is a diagram schematically illustrating the operation flow of the sheet stacking apparatus according to the second embodiment.

Fig. 8 is an explanatory diagram showing a configuration of a sheet stacking apparatus according to a third embodiment.

Fig. 9 is a diagram schematically illustrating the flow of operation of the sheet stacking apparatus according to the third embodiment.

Fig. 10 is a front view of a sheet stacking apparatus showing a modification of the first tray and the second tray.

Fig. 11 is a diagram schematically illustrating an operation flow according to a modification of the first tray and the second tray.

Description of the reference numerals

1 image forming apparatus

5 original reading device

11 photosensitive body

12 charged part

13 image exposure part

14 developing part

15A transfer section

15B separation part

16 cleaning device

17A paper tray

17B intermediate conveying part

17C paper discharge roller

17D conveying path switching plate

17E turnover conveying part

18 fixing device

19 image forming control section

2 paper stacking device

2a housing

20 paper discharge part

21 first tray

21a upper surface

22 first support member

23 base part

24 lifting device

25 second tray

25a upper surface

26 second support member

27 base part

28 front and rear driving device

29 base part

30 drive part

31 stack control part

40 transport vehicle

Detailed Description

< first embodiment >

Fig. 1 is a front view schematically showing the configuration of an image forming system according to the present embodiment. The image forming system of the present embodiment includes an image forming apparatus 1 and a sheet stacking apparatus 2.

The image forming apparatus 1 is an electrophotographic image forming apparatus such as a copying machine, and forms an image on a sheet P based on image data. The image forming apparatus 1 includes an original reading device 5, a photoreceptor 11, a charging section 12, an image exposing section 13, a developing section 14, a transfer section 15A, a separating section 15B, a cleaning device 16, a fixing device 18, and an image formation control section 19.

The document reading apparatus 5 includes an automatic document feeding portion that is disposed in an upper portion of a housing of the image forming apparatus 1 and automatically moves a document when reading an image. The document reading apparatus 5 reads an image formed on a document and outputs a predetermined image signal. The output image signal is made into image data by being subjected to a/D conversion.

An image reading control section (not shown) included in the document reading apparatus 5 performs processing such as shading correction, dithering, and compression on the image data, and outputs the data obtained by the processing to the image formation control section 19 as final image data. Note that the image formation control section 19 may acquire image data not only from the document reading apparatus 5 but also from a personal computer or another image forming apparatus 1 connected to the image forming apparatus 1.

The surface of the photoreceptor 11 is uniformly charged by the charging section 12. The image exposure section 13 performs scanning exposure of the surface of the photoreceptor 11 with a laser beam based on output information output from the image formation control section 19 based on image data. Thereby, a latent image is formed on the surface of the photoreceptor 11. The developing unit 14 develops the latent image with toner to form an image (toner image) on the surface of the photoreceptor 11.

The sheets P stored in the sheet tray 17A are supplied to the transfer section 15A. The transfer section 15A transfers the image on the surface of the photoreceptor 11 to the paper P. The separation section 15B separates the sheet P on which the image is transferred from the photoreceptor 11. The cleaning device 16 removes toner remaining on the surface of the photoreceptor 11 after the image is transferred to the paper P. The intermediate conveyance section 17B conveys the separated paper P to the fixing device 18.

The fixing device 18 performs a fixing process of fixing an image on the paper P by heating and pressing. The paper discharge roller 17C discharges the paper P subjected to the fixing process to the outside of the apparatus.

On the other hand, when forming images on both sides of the paper P, the transport direction of the paper P subjected to the fixing process by the fixing device 18 is switched from the paper discharge roller 17C side to the lower side (the reversing and transporting unit 17E) by the transport path switching plate 17D. The reversing and conveying section 17E reverses the front and back sides of the sheet P by reversing the sheet P, and then conveys the sheet P to the transfer section 15A.

The image formation control section 19 controls the image forming apparatus 1. As the image formation control unit 19, a microcomputer mainly including a CPU, a ROM, a RAM, and an I/O interface can be used. The CPU executes various programs (processors). The ROM stores various programs executed by the CPU in the form of program codes readable by the CPU. In addition, the ROM stores data necessary for executing the program. The RAM is a memory constituting a storage area for work. The program and data stored in the ROM are expanded on the RAM if read by the CPU. Then, the CPU performs various processes based on the programs and data developed on the RAM.

The sheet stacking apparatus 2 is an apparatus that stacks and stores sheets P supplied from the image forming apparatus 1 when the sheets P are taken into the apparatus. The sheet stacking apparatus 2 is disposed on the downstream side of the image forming apparatus 1 so as to be adjacent to the image forming apparatus 1 in the sheet conveying direction. The sheet stacking apparatus 2 is mainly configured by a sheet discharge unit 20, a first tray 21, a lifting device 24, a second tray 25, a front-rear driving device 28, and a stack control unit 31. Here, fig. 2 is a configuration diagram showing a main part of the sheet stacking apparatus 2 mainly including the first tray 21 and the second tray 25.

Upon receiving the sheet P supplied from the image forming apparatus 1, the sheet discharging unit 20 takes the sheet P into the apparatus interior (inside the casing 2 a) of the sheet stacking apparatus 2 and discharges the sheet P to the first tray 21. The position of the paper discharge unit 20 is set in correspondence with the paper discharge roller 17C of the image forming apparatus 1.

The first tray 21 is a tray on which the sheets P discharged from the sheet discharge portion 20 are stacked. The first tray 21 is configured to be movable in the vertical direction. The first tray 21 is formed of a plurality of first supporting members 22 formed in a comb-like shape. A plurality of first supporting members 22 are horizontally arranged at predetermined intervals in the sheet conveying direction. Each first support member 22 extends from a base member 23 located on the rear side (device inner side) to the front side (device proximal side).

The lifting device 24 is a device that vertically lifts (moves) the first tray 21. The lifting device 24 is mainly composed of a drive motor, a drive pulley rotated by power transmission from the drive motor, a driven pulley, a timing belt bridged between the drive pulley and the driven pulley and connected to the first pallet 21, and the like. The lifting device 24 is controlled by the stack control unit 31.

The lifting device 24 sets the first tray 21 at the initial position. This initial position corresponds to the position of the first tray 21 when the stacking of the sheets P is started. When the sheet P is discharged from the sheet discharge unit 20, the lifting device 24 lowers (moves) the first tray 21 so that the uppermost sheet P stacked on the first tray 21 is maintained at a predetermined height. The first tray 21 is lowered along with the stacking of the sheets P until the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number. The upper limit number is a value for setting the maximum number of sheets P stackable on the first tray 21, and is set, for example, under mechanical constraints due to the structure of the sheet stacking apparatus 2. On the other hand, the set number is a number set by a user or the like, for example, among the maximum number of sheets P stacked on the first tray 21, and may be set to an arbitrary number within a range of 1 sheet or more and less than the upper limit number. The position from the initial position to the position reached when the first tray 21 stacks the upper limit number of sheets P corresponds to the sheet stacking position of the first tray 21.

On the other hand, when the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number, the lifting device 24 lowers the first tray 21 to the sheet delivery position where the sheets P are delivered to the second tray 25. When the delivery of the sheet P from the first tray 21 to the second tray 25 is completed, the lifting device 24 lifts (moves) the first tray 21 from the sheet delivery position to the initial position.

The second tray 25 is disposed below the first tray 21. The second tray 25 is a tray for receiving the sheets P stacked on the first tray 21 from the first tray 21. The second tray 25 is formed of a plurality of second supporting members 26 formed in a comb-like shape. A plurality of second supporting members 26 are horizontally arranged at predetermined intervals in the sheet conveying direction. The base member 27 is located below the second support members 26, and each of the second support members 26 stands on the base member 27.

Fig. 3 is an explanatory diagram showing a relationship between the second tray 25 and the first tray 21. The plurality of second supporting members 26 are provided at positions corresponding to a plurality of gap portions formed in the first tray 21, that is, spaces existing between adjacent first supporting members 22. Therefore, even when the first tray 21 moves downward and the first tray 21 and the second tray 25 are present on the same horizontal plane, they do not interfere with each other. That is, the first tray 21 and the second tray 25 can be vertically displaced. According to this configuration, by lowering upper surface 21a of first tray 21 below upper surface 25a of second tray 25, sheets P stacked on first tray 21 can be delivered to second tray 25. The paper feed position is determined in advance such that the upper surface 21a of the first tray 21 is located below the upper surface 25a of the second tray 25, based on the height of the second tray 25.

The front-rear drive unit 28 includes a base 29 on which the second tray 25 is removably mounted, and a drive unit 30 which moves the base 29 in the front-rear direction and feeds the second tray 25 to the outside of the apparatus. The driving unit 30 is mainly composed of a driving motor, a driving pulley and a driven pulley that are rotated by power transmission from the driving motor, a timing belt that is bridged between the driving pulley and the driven pulley and is coupled to the base unit 29, and the like. The front-rear driving device 28 is controlled by the stack control section 31.

The front-rear driving device 28 sets the second tray 25 at the initial position. The initial position is a position that exists inside the apparatus below the first tray 21 and is capable of delivering the sheet P between the first tray 21 and the first tray 21 when the first tray 21 is lowered. When receiving the sheet P from the first tray 21, the front-rear driving device 28 moves the second tray 25 forward, and feeds the second tray 25 to the outside of the apparatus. Thus, the second tray 25 is removed from the pedestal portion 29 and attached to the transport vehicle 40 that transports the sheet P. As a result, the paper P can be conveyed together with the second tray 25 by the conveyance vehicle 40.

On the other hand, when the sheets P are removed from the second tray 25 mounted on the transport vehicle 40, the second tray 25 is detached from the transport vehicle 40 and mounted on the pedestal portion 29. When the second tray 25 is mounted on the mount 29, the front-rear driving device 28 moves the second tray 25 rearward to return the second tray 25 to the initial position. Note that a shutter, not shown, is provided on the housing 2a of the sheet stacking apparatus 2. The shutter opens and closes in response to the entrance and exit of the second tray 25.

The stack control section 31 controls the sheet stacking apparatus 2. As the stack control unit 31, a microcomputer mainly including a CPU, a ROM, a RAM, and an I/O interface can be used. The CPU executes various programs (processors). The ROM stores various programs executed by the CPU in the form of program codes readable by the CPU. In addition, the ROM stores data necessary for executing the program. The RAM is a memory constituting a storage area for work. The program and data stored in the ROM are expanded on the RAM if read by the CPU. Then, the CPU performs various processes based on the programs and data developed on the RAM.

The following describes operations of the image forming system according to the present embodiment. Here, fig. 4 is a flowchart showing an operation flow of the image forming system. Fig. 5 is a diagram illustrating an operation flow of the sheet stacking apparatus 2. Triggered by a print start command from the user, the image formation control unit 19 and the stack control unit 31 execute the processing shown in the flowchart.

First, in step S10, the image formation control unit 19 controls each unit of the image forming apparatus 1 to execute an image forming operation. This image forming operation performs a series of processes of feeding the sheet P, forming an image on the fed sheet P, and discharging the sheet P on which the image has been formed to the sheet stacking apparatus 2. Similarly, the stack control unit 31 controls the sheet discharge unit 20, receives the sheet P supplied from the image forming apparatus 1 by the sheet discharge unit 20, and discharges the sheet P to the first tray 21 ((a) of fig. 5).

In step S11, the stack control unit 31 determines whether the number of sheets P stacked on the first tray 21 has reached the upper limit number or the set number. When the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number, an affirmative determination is made in step S11, and the process proceeds to step S12. On the other hand, if the number of sheets P stacked on the first tray 21 has not reached the upper limit number of sheets or the set number of sheets, a negative determination is made in step S11, and the process returns to step S10.

In step S12, the image formation control unit 19 controls each unit of the image forming apparatus 1 to stop the image forming operation. Similarly, the stack control unit 31 controls the paper discharge unit 20 to stop discharging the paper P to the first tray 21.

In step S13, the stack control unit 31 controls the lifting device 24 to lower the first tray 21 (fig. 5 (b)). The lowering operation of the first tray 21 is performed until the first tray 21 reaches the sheet delivery position. The paper delivery position is set according to the height of the second tray 25 mounted on the pedestal portion 29. If the first tray 21 reaches the sheet delivery position, the sheets P stacked on the first tray 21 are delivered from the first tray 21 to the second tray 25 because the upper surface 25a of the second tray 25 reaches a position above the upper surface 21a of the first tray 21 ((c) of fig. 5).

In step S14, the stack controller 31 controls the front-rear drive device 28 to move the pedestal portion 29 forward (fig. 5 (d)). This forward movement is performed until the base 29 and the second tray 25 mounted on the base 29 are discharged to the outside of the apparatus.

In step S15, the stack control unit 31 controls the lifting device 24 to move the first tray 21 upward (fig. 5 (e)). The raising operation of the first tray 21 is performed until the first tray 21 reaches the initial position.

The second tray 25 discharged to the outside of the apparatus is removed from the pedestal portion 29 in a state where the sheets P are stacked, and is mounted on the transport vehicle 40 prepared outside the apparatus ((f) of fig. 5). The second tray 25 and the sheets P stacked on the second tray 25 can be conveyed by the conveyance vehicle 40.

In step S16, the image formation control unit 19 controls each unit of the image forming apparatus 1 to resume the image forming operation. Similarly, the stack control unit 31 controls the paper discharge unit 20 to restart the discharge of the paper P to the first tray 21. At the time point when the first tray 21 reaches the initial position or a time point slightly later than the initial position, the image forming operation is restarted and the sheet discharge to the first tray 21 is restarted so that the sheet P can be discharged to the first tray 21.

In step S17, the image formation control section 19 determines whether or not the job has ended. In the case where the task has ended, an affirmative determination is made in step S17, and the present routine is ended. On the other hand, in a case where the task has not ended, a negative determination is made in step S17, and the process returns to step S10.

If the sheets P stacked on the second tray 25 are removed and the second tray 25 becomes empty, the second tray 25 is removed from the transport vehicle 40 and mounted on the pedestal portion 29. After the second tray 25 is mounted, the stack controller 31 controls the front-rear drive device 28 to move the pedestal portion 29 backward. This retreating operation is performed until the base 29 and the second pallet 25 mounted on the base 29 reach the initial position. Thereby, the second tray 25 is returned to the inside of the apparatus.

Note that the second tray 25 is preferably returned to the pedestal portion 29 before the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number. Further, since there is a possibility that the state in which the holding base 29 is discharged to the outside of the apparatus may be obstructed, the base 29 may be returned to the inside of the apparatus after the second tray 25 is removed from the base 29 and before it is attached to the base 29 again.

As described above, in the present embodiment, the first tray 21 and the second tray 25 have at least three operation states as their operation states. Specifically, the first operating state is an operating state in which the first tray 21 is located at a sheet stacking position at which the sheets P discharged from the sheet discharge portion 20 are stacked, and the second tray 25 is located at a position lower than the first tray 21. The second operating state is an operating state in which the upper surface 25a of the second tray 25 is positioned above the upper surface 21a of the first tray 21 and the sheets P stacked on the first tray 21 can be delivered to the second tray 25. The third operating state is an operating state in which the first tray 21 having delivered the sheet P to the second tray 25 is returned to the sheet stacking position.

According to this configuration, since the paper P can be delivered to the second tray 25, the paper P can be discharged to the outside of the apparatus via the second tray 25 while the first tray 21 is left in the apparatus. In addition, the first tray 21, which has delivered the sheet P to the second tray 25, can be returned to the sheet stacking position (initial position). Therefore, the stacking of the sheets P to the first tray 21 can be promptly restarted. As a result, the occurrence of downtime can be suppressed.

The first tray 21 and the second tray 25 have a gap for passing the other tray so that the trays do not interfere with each other on the same plane. Specifically, the first tray 21 and the second tray 25 are each formed in a comb-tooth shape.

According to this configuration, since the first tray 21 and the second tray 25 do not interfere with each other on the same plane, the upper surface 21a of the first tray 21 can be positioned below the upper surface 25a of the second tray 25. This allows the paper P to be easily delivered from the first tray 21 to the second tray 25.

In the present embodiment, the sheet stacking apparatus 2 moves the first tray 21 to reach the sheet delivery position corresponding to the height of the second tray 25, thereby changing from the first operating state to the second operating state.

According to this configuration, by moving the first tray 21, the paper P can be easily delivered from the first tray 21 to the second tray 25.

In the present embodiment, in the first operating state, the second tray 25 is positioned below the first tray 21, and the first tray is lowered to shift from the first operating state to the second operating state.

According to this configuration, by moving the first tray 21 in the vertical direction, the paper P can be easily delivered from the first tray 21 to the second tray 25. In addition, since the first tray 21 has a function of being lifted and lowered in the up-and-down direction when stacking the sheets P, the sheets P can be delivered from the first tray 21 to the second tray 25 along with the conventional configuration.

In addition, in the present embodiment, the sheet stacking apparatus 2 further includes a pedestal portion 29 that moves between the inside and the outside of the apparatus. In this case, the second tray 25 is mounted on the pedestal portion 29. According to this configuration, the second tray 25 can be moved inside and outside the apparatus by moving the pedestal portion 29.

In the present embodiment, the second tray 25 is detachably mounted on the pedestal portion 29. According to this configuration, since the second tray 25 is detachable, the sheets P can be handled together with the second tray 25.

In the present embodiment, the sheet stacking apparatus 2 further includes a transport vehicle 40, and the transport vehicle 40 carries the second tray 25 discharged to the outside of the apparatus and transports the second tray 25.

According to this configuration, since the second tray 25 can be conveyed by the conveyance vehicle 40, a large number of sheets P can be easily conveyed.

< second embodiment >

The image forming system according to the second embodiment will be described below. The image forming system according to the second embodiment is different from the first embodiment in the configuration of the sheet stacking apparatus 2. Description of overlapping contents with the first embodiment will be omitted, and differences will be mainly described below.

Fig. 6 is an explanatory diagram showing a structure of the sheet stacking apparatus 2 according to the second embodiment. The sheet stacking apparatus 2 is mainly configured by a sheet discharge unit 20 (not shown in fig. 6), a first tray 21, a lifting device 24, a second tray 25, a transport vehicle 40, and a stack control unit 31. The configurations of the sheet discharging unit 20, the first tray 21, the lifting device 24, and the stack control unit 31 are the same as those of the first embodiment.

In the present embodiment, the second tray 25 is mounted on the conveyance vehicle 40 housed in the apparatus. The transport vehicle 40 transports the second tray 25 so as to be movable from the inside of the apparatus to the outside of the apparatus.

The operation of the sheet stacking apparatus 2 according to the present embodiment will be described below. Fig. 7 is a diagram schematically illustrating the flow of operation of the sheet stacking apparatus 2 according to the second embodiment.

First, the discharge of the sheet P discharged from the image forming apparatus 1 to the first tray 21 is started ((a) of fig. 7). If the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number, the stack control unit 31 controls the lifting device 24 to move the first tray 21 downward (fig. 7 (b)). The lowering operation of the first tray 21 is performed until the first tray 21 reaches the sheet delivery position. The paper delivery position is set according to the height of the second tray 25 mounted on the conveyance vehicle 40. If the first tray 21 reaches the sheet delivery position, since the upper surface 25a of the second tray 25 reaches a position above the upper surface 21a of the first tray 21, the sheets P to be stacked on the first tray 21 are delivered from the first tray 21 to the second tray 25 ((c) of fig. 7).

The transport vehicle 40 having delivered the sheet P to the second tray 25 is carried out to the outside of the apparatus by the user ((d) of fig. 7). If it is determined that the transport vehicle 40 has been carried out outside the apparatus based on the detection result of the sensor (not shown), the stack control unit 31 controls the lifting device 24 to lift the first tray 21 ((e) of fig. 7). The raising operation of the first tray 21 is performed until the first tray 21 reaches the initial position.

The second tray 25 carried out together with the transport vehicle 40 can be transported to a destination by the transport vehicle 40. Then, by returning the first tray 21 to the initial position, the image forming operation and the discharge of the paper P to the first tray 21 can be started.

As described above, according to the present embodiment, the second tray 25 is mounted on the conveyance vehicle 40, and the conveyance vehicle 40 is configured to be able to be housed inside the apparatus.

According to this configuration, the second tray 25 and the sheets P can be moved outside and inside the apparatus by the transport vehicle 40. Further, since the transport vehicle 40 is housed inside the apparatus, it is not necessary to transfer the second tray 25 to the transport vehicle 40. This enables the paper P delivered from the first tray 21 to be easily conveyed.

< third embodiment >

The image forming system according to the third embodiment will be described below. The image forming system according to the third embodiment is different from the first embodiment in the configuration of the sheet stacking apparatus 2. Description of overlapping contents with the first embodiment will be omitted below, and differences will be mainly described below.

Fig. 8 is an explanatory diagram showing a structure of the sheet stacking apparatus 2 according to the third embodiment. The sheet stacking apparatus 2 is mainly configured by a sheet discharge unit 20 (not shown in fig. 8), a first tray 21, a lifting device 24, a plurality of second trays 25, a front-rear drive device 28, and a stack control unit 31. The configurations of the sheet discharging unit 20, the first tray 21, the lifting device 24, the front-rear driving device 28, and the stack control unit 31 are the same as those of the first embodiment.

In the present embodiment, the plurality of second trays 25 are mounted on the pedestal portion 29 in a vertically overlapped state. The structure of each second tray 25 is the same as that of the first embodiment.

The operation of the sheet stacking apparatus 2 according to the present embodiment will be described below. Fig. 9 is a diagram schematically illustrating the flow of operation of the sheet stacking apparatus 2 according to the third embodiment.

First, the sheets P discharged from the image forming apparatus 1 are discharged to the first tray 21, and if the number of sheets P stacked on the first tray 21 reaches the upper limit number or the set number, the stack control unit 31 controls the lifting device 24 to move the first tray 21 downward (fig. 9 (a)). The lowering operation of the first tray 21 is performed until the first tray 21 reaches the sheet delivery position. The paper delivery position is set according to the height of the uppermost second tray 25 among the plurality of second trays 25 mounted on the pedestal portion 29. More specifically, the sheet delivery positions are set in the following relationship: when the first tray 21 reaches the sheet delivery position, the upper surface 25a of the uppermost second tray 25 is positioned above the upper surface 21a of the first tray 21. If the first tray 21 reaches the sheet delivery position, the sheet P stacked on the first tray 21 is delivered from the first tray 21 to the uppermost second tray 25 because the upper surface 25a of the uppermost second tray 25 reaches a position above the upper surface 21a of the first tray 21 ((b) of fig. 9).

After the sheet P is delivered to the second tray 25, the carriage unit 29 is advanced to discharge the second tray 25 to the outside of the apparatus. Thereby, the uppermost second tray 25 is removed from the pedestal portion 29 and mounted on the transport vehicle 40 prepared outside the apparatus. After the uppermost second tray 25 is mounted on the transport vehicle 40, the pedestal portion 29 is returned to the initial position. Thereby, the remaining second tray 25 is returned to the inside of the apparatus ((c) of fig. 9).

After the remaining second tray 25 is returned to the inside of the apparatus, the stack controller 31 controls the lifting device 24 to lift the first tray 21 (fig. 9 (d)). The raising operation of the first tray 21 is performed until the first tray 21 reaches the initial position. By returning the first tray 21 to the initial position, the image forming operation is started and the sheet P is discharged to the first tray 21. Then, the above operation is repeated for the new uppermost second tray 25 (fig. 9 (e), (f)).

As described above, in the present embodiment, a plurality of second trays 25 are stacked in the vertical direction. In this case, the sheet delivery position is switched according to the height of the second tray 25 positioned on the uppermost layer.

According to this configuration, since the plurality of second trays 25 are prepared, even in a situation where one second tray 25 is discharged to the outside of the apparatus, the paper P can be delivered to the second tray 25 left on the pedestal portion 29 without waiting for the return of the second tray 25. This can suppress the occurrence of downtime.

Note that, in each of the above embodiments, the first tray 21 and the second tray 25 have a gap for allowing the other tray to pass through so that the trays do not interfere with each other on the same plane. However, the method of delivering the sheet P from the first tray 21 to the second tray 25 is not limited thereto. Here, fig. 10 is a front view of the sheet stacking apparatus 2 showing a modification of the first tray 21 and the second tray 25.

Specifically, the second tray 25 is disposed on the side of the first tray 21 so as to be laterally aligned with the first tray. According to this modification, interference on the same plane can be suppressed without providing a gap for allowing the other tray to pass through the first tray 21 and the second tray 25.

In this modification, if the number of sheets P stacked on the first tray 21 reaches the set number or the upper limit number, the stack control unit 31 controls the lifting device 24 to move the first tray 21 downward (fig. 11 (a)). The lowering operation of the first tray 21 is performed until the first tray 21 reaches the sheet delivery position. The paper delivery position is set according to the height of the second tray 25 ((b) of fig. 11). More specifically, the sheet delivery positions are set in the following relationship: when the first tray 21 reaches the sheet delivery position, the upper surface 25a of the second tray 25 arranged in the lateral direction is positioned above the upper surface 21a of the first tray 21. Any method can be used to deliver the sheet P from the first tray 21 to the second tray 25. For example, as with a belt conveyor. After the delivery of the sheet P is completed, the first tray 21 is returned to the initial position ((c) of fig. 11). This enables the start of the image forming operation and the discharge of the sheet P to the first tray 21.

Although the image forming system and the sheet stacking apparatus according to the embodiment of the present invention have been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention.

For example, in the present embodiment, the image forming system is configured by an image forming apparatus that performs an image forming function and a sheet stacking apparatus that stacks sheets. However, the sheet processing apparatus itself constituting the image forming system also functions as one side of the present invention. In addition, the image forming system may be configured such that the image forming apparatus and the sheet stacking apparatus are each configured as an independent apparatus, and the sheet stacking apparatus may be provided as one function of the image forming apparatus.

In addition, in the present embodiment, the sheet stacking apparatus has a dedicated control section (stacking control section) and the control of the sheet stacking apparatus is executed by the control section. However, the control unit that controls the image forming apparatus may control the sheet stacking apparatus, and in this case, the stack control unit may be omitted.

In the present embodiment, paper is not limited to recording media produced using pulp as a main raw material, and includes recording media on which images can be formed by an image forming apparatus.

In the present embodiment, the first tray is moved when the sheet is delivered. However, the second tray may be moved to a paper delivery position corresponding to the height of the first tray, that is, a position where the upper surface of the second tray is located above the upper surface of the first tray, so that the second tray is shifted from the first operating state to the second operating state. In addition, both the first tray and the second tray may be moved to shift from the first operating state to the second operating state.

Claims

1. A sheet stacking apparatus, characterized by comprising:

a first tray that stacks sheets;

a paper discharge unit configured to discharge paper supplied from an outside of the apparatus to the first tray;

a second tray that receives the sheets stacked on the first tray and discharges the received sheets to the outside of the apparatus;

a control unit that controls an operation state of the first tray and the second tray;

the first tray and the second tray have:

a first operating state in which the first tray is at a sheet stacking position at which sheets discharged from the sheet discharge unit are stacked and the second tray is positioned below the first tray;

a second operating state in which the upper surface of the second tray is positioned above the upper surface of the first tray and the sheets stacked on the first tray can be delivered to the second tray;

and a third operating state in which the first tray delivered with the sheets to the second tray is returned to the sheet stacking position.

2. The sheet stacking apparatus according to claim 1,

the first tray and the second tray each have a gap for passing another tray so that the trays do not interfere with each other on the same plane.

3. The sheet stacking apparatus according to claim 1 or 2,

the first tray is moved to reach a sheet delivery position corresponding to the height of the second tray, thereby shifting from the first operating state to the second operating state.

4. The sheet stacking apparatus according to claim 3,

in the first operating state, the second tray is positioned below the first tray,

the first tray is lowered to transition from the first operating state to the second operating state.

5. The sheet stacking apparatus according to claim 3 or 4,

a plurality of second trays are overlapped in the vertical direction,

switching the sheet delivery position according to a height of the second tray located at the uppermost layer.

6. The sheet stacking apparatus according to any one of claims 1 to 5,

the sheet stacking apparatus also has a pedestal portion that moves between the inside and the outside of the apparatus,

the second tray is mounted on the pedestal portion.

7. The sheet stacking apparatus according to claim 6,

the second tray is detachably mounted on the pedestal portion.

8. The sheet stacking apparatus according to any one of claims 1 to 5,

the sheet stacking apparatus further has a transport vehicle that carries the second tray and transports the second tray,

the transport vehicle is configured to be able to be housed inside the apparatus.

9. The sheet stacking apparatus according to any one of claims 1 to 5,

the sheet stacking apparatus further includes a transport vehicle that carries the second tray discharged outside the apparatus and transports the second tray.

10. The sheet stacking apparatus according to claim 1 or 2,

the second tray is moved to reach a sheet delivery position corresponding to the height of the first tray, and thereby the first operating state is changed to the second operating state.

11. The sheet stacking apparatus according to claim 1 or 2,

the first tray and the second tray are moved to reach a predetermined sheet delivery position, and the first operating state is changed to the second operating state.

12. An image forming system is characterized by comprising

An image forming apparatus that discharges a sheet on which an image is formed;

the sheet stacking apparatus according to any one of claims 1 to 11, which stacks sheets discharged from the image forming apparatus.