JP2003089473A - Sheet post-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate waiting of a next image forming process without impairing throughput of an image forming device. SOLUTION: The sheet post-processing device is characterized by that it has the image forming device forming an image, the sheet post-processing device post-processing a sheet, a buffer module device temporarily storing a sheet delivered from the image forming device, a loading means of loading the sheet conveyed from the buffer module device, and a second full load detecting means of detecting a full load of the loading means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus, and more particularly to a sheet post-processing apparatus to which a buffer module device used in an image forming apparatus such as a copying machine or a laser beam printer is connected.

[0002]

2. Description of the Related Art Conventionally, when the stacking tray of a sheet post-processing apparatus reaches a predetermined amount, a warning that the stacking tray is full is issued from the operation unit of the image forming apparatus, and image formation is performed until the stacking tray is fully unloaded. It was suspended.

[0003]

However, in the above-mentioned conventional example, since the image formation is suspended until the stacking tray is fully loaded, not only the processing capacity originally possessed by the image forming apparatus is impaired, but also another operator is required. It also causes the next image forming process to be executed to be made to wait.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art. The object of the present invention is not to impair the processing capability of the image forming apparatus and to wait for the next image forming processing. It is something that is not allowed.

[0005]

In order to achieve the above-mentioned object, the present invention is a sheet post-processing apparatus for post-processing a sheet discharged from an image forming apparatus for forming an image, which is discharged from the image forming apparatus. Buffer module device for temporarily accumulating the sheets, a first full load detecting means for detecting whether or not the sheets accumulated in the buffer module device are full, and a stacking means for stacking the sheets conveyed from the buffer module device. And a second full load detecting means for detecting a full load of the loading means, and the second full load detecting means determines that the loading means is full load,
When the first full load detecting means determines that the buffer module device is not full, only the sheet conveyance from the buffer module device to the stacking means is interrupted, and the buffer module device by the first full load detecting means is interrupted. A sheet post-processing apparatus to which a buffer module device is connected so that the sheets are continuously discharged from the image forming apparatus to the buffer module apparatus until the full load of the sheet is detected.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Example 1) (Explanation of FIG. 1) FIG. 1 is a sectional view showing an internal configuration of an image forming apparatus system according to an embodiment of the present invention.

The image forming apparatus 1000 is a document feeder 10
0, image reader 200, printer 300, buffer module 400, folding device 500, finisher body 6
Has 00.

The document feeder 100 conveys the set documents one by one from the top page in order from left to right on the platen glass 102 via a curved path, and then discharges them to a paper discharge tray 112. To do. At this time, the scanner unit 104 is in a state of being held at a predetermined position, and the document is read by passing the document on the scanner unit 104 from left to right.

When the original passes, the light of the lamp 103 of the scanner unit 104 is applied to the original, and the reflected light from the original is guided to the image sensor 109 via the mirrors 105, 106, 107 and the lens 108. It is also possible to read the document by transporting the document onto the platen glass 102 by the document feeding device 100, stopping the document, and moving the scanner unit 104 from left to right.

The image of the original read by the image sensor 109 is subjected to image processing and sent to the exposure controller 110. The exposure controller 110 outputs laser light according to the image signal. This laser light is applied to the photosensitive drum 111, and an electrostatic latent image is formed on the photosensitive drum 111. The electrostatic latent image on the photosensitive drum 111 is developed by the developing device 113, and the developer on the photosensitive drum 111 is stored in the cassettes 114, 1
The transfer unit 116 transfers the sheet to the sheet fed from any one of the manual feed unit 125, the manual feed unit 125, and the double-sided conveyance path 124.

The sheet on which the developer is transferred is fixed to the fixing unit 117.
Then, the fixing process of the developer is performed. The sheet having passed through the fixing unit 117 is once guided to the path 122 by the flapper 121, and after the trailing edge of the sheet has passed through the flapper 121, the sheet is switched back and guided to the discharge roller 118 by the flapper 121.

As a result, the surface on which the developer has been transferred is ejected from the printer 300 by the ejection roller 118 with the surface facing down (face down).

It should be noted that the path 122 is used when an image is formed on a hard sheet such as an OHP sheet from the manual sheet feeding section 125.
The surface on which the developer is transferred is ejected from the ejection roller 118 in an upward state (face-up) without being guided to.

When images are formed on both sides of the sheet, the sheet is ejected straight from the fixing unit 117.
8, the sheet is switched back immediately after the trailing edge of the sheet passes through the flapper 121, and the sheet is guided to the double-sided conveyance path 124 by the flapper 121. The sheet discharged from the discharge roller 118 is sent to the buffer module 400.

The buffer module 400 has a buffer tray 403 capable of temporarily storing sheets, and the processing speed of the folding processing unit 500 or the finisher main body 600 to which the sheets discharged from the image forming apparatus 1000 are connected to the next stage. In accordance with the above, switching control of the entrance switching flapper 401 is performed to perform path switching between the through path 411 and the entrance path 412. Thereby, adjustment control of the processing capabilities of the image forming apparatus 1000 and the post-processing apparatus is performed. The detailed control of the buffer module 400 will be described later.

The folding device 500 folds the sheet into a Z shape. The folding device 500 is the buffer module 4
The paper discharged from 00 is introduced, and the finisher main body 6
It has a folding conveyance horizontal path 501 for guiding to the 00 side.
A folding path selection flapper 502 is provided at the exit of the folding conveyance horizontal path 501 (on the finisher main body 600 side). When performing folding processing, the folding path selection flapper 502 is turned on, and the sheet is guided to the folding path 503. The sheet guided to the folding path 503 is stored in the folding roller 5
It is transported to 04 and folded into a Z shape. On the other hand, when the folding process is not performed, the folding path selection flapper 502 is turned off, and the sheet is transferred from the buffer module 400 via the folding conveyance horizontal path 501 to the finisher 600.
Sent directly to.

In the finisher main body 600, sorting processing,
Performs binding processing, punching, and other processing. A pair of entrance rollers 6 for guiding the sheet discharged through the folding device 500 to the inside.
Has 01. A switching flapper 604 for guiding the sheet to the finisher path 602 or the first bookbinding path 603 is provided downstream of the pair of entrance rollers 601.

The sheet guided to the finisher path 602 is sent toward the buffer roller 606 via the pair of carrying rollers 605. Transport roller 605 and buffer roller 60
Reference numeral 6 is configured to be capable of forward and reverse rotation.

Conveying roller pair 605 and buffer roller 60
A punching unit 607 is provided between the sheets 6 and operates as required to make a hole in the vicinity of the rear end of the conveyed sheet.

The buffer roller 606 is a roller capable of stacking and winding a predetermined number of sheets of paper sent on the outer periphery thereof via a pair of transport rollers 605, and the outer periphery of the roller is covered with the sheets of paper during rotation thereof. Pressing rollers 608,609,6
Wrapped by 10.

A switching flapper 611 is arranged between the pressing rollers 609 and 610, and a switching flapper 612 is arranged downstream of the pressing roller 610. The switching flapper 611 separates the paper wound around the buffer roller 606 from the buffer roller 606 and removes the non-sort path 6.
13 or a flapper for guiding to the sort path 614, and the switching flapper 612 sorts the paper wound around the buffer roller into the sort path 614 or the buffer path 6
It is a flapper for leading to 15.

The paper led to the non-sort path 613 is
The sheet is discharged onto the sample tray 701 via the discharge roller pair 616. The sheet guided to the sort path 614 passes through the pair of conveying rollers 617 and the pair of discharging rollers 618, and then the intermediate tray 6
19 is loaded. The stack of sheets stacked on the processing tray 619 is subjected to alignment processing and stapling processing as needed, and then the stack tray 70 is discharged by the discharge roller 620.
Is discharged above zero.

A stapler 621 is used for stapling processing for binding sheets stacked on the processing tray 619. Further, the stack tray 700 is configured to be self-propelled in the vertical direction.

First binding path 603, second binding path 622
The paper from is stored in the storage guide by the first conveying roller pair 623 and the second conveying roller pair 624, and the third sheet
The sheet is conveyed by the conveying roller 625 until the leading edge of the sheet comes into contact with the movable sheet positioning member 626. The sheet bundle extruded by the folding roller pair 627 and the protrusion member 628 is folded and then discharged to the saddle tray 702.

The inserter 800 is the finisher body 600.
The sheet bundle stacked on the tray 801 is sequentially separated and conveyed to the finisher path 602 or the second bookbinding path 622.

The bundle of sheets is set with the front side facing up, and is conveyed by a sheet feeding roller 802 to a separating section including a conveying roller 803 and a separation belt 807, and is sequentially separated from the topmost sheet one by one.

A pull-out roller pair 804 is arranged in the vicinity of the downstream side of the separating section and stably conveys the separated sheet to the downstream side. Inlet roller pair 601 and drawing roller pair 8
A transport roller pair 805 is provided in the middle of 04.

The transport path 806 from the inserter merges with the transport path from the buffer module 400 upstream of the pair of entrance rollers 601.

Next, the configuration of the buffer module 400 will be described in detail with reference to FIG.

As shown in FIG. 2, the buffer module 400 has a pair of entrance rollers 404 for guiding the paper discharged from the printer 300 to the inside. Downstream of the pair of entrance rollers 404, an entrance switching flapper 401 for guiding the sheet to the through path 411 or the entrance path 412,
An exit switching flapper 402 for discharging the paper from the through path 411 and the paper from the paper discharge path 413 to the outside of the machine,
Inlet sensor 414 for detecting paper, paper discharge sensor 4
15 are provided.

The sheet guided to the through path 411 by the switching of the entrance switching flapper 401 is sent toward the sheet discharge roller pair 406 via the pair of transport rollers 405 (405a, 405b, 405c). Paper ejection roller pair 406
The sheet sent to is discharged to the outside of the buffer module 400 and sent to the folding device 500.

By switching the inlet switching flapper 401,
The sheet guided to the entrance path 412 is sent to the buffer tray 403 via the transport roller 407 and is stacked on the buffer tray 403.

At the lower part of the buffer tray 403, there is provided a feeding means for feeding the stacked sheets to the folding device 500 at the next stage. This feeding means includes a half-moon roller 409, a separation roller 408, a separation conveyance roller 418,
A separation sensor 417 and a sheet presence / absence detection sensor 416 for detecting the presence / absence of sheets on the buffer tray 403 are configured.

Here, the half-moon roller 409 and the separation roller 4
08 is rotated by the separation motor 434 to separate the sheets one by one from the lowermost part of the stack of sheets stacked inside the buffer tray 403. The separation sensor 417 is a sensor that detects whether or not the separation is performed from the buffer tray 403. The separated sheet is conveyed through the separation / conveyance roller pair 418 to the conveyance roller pair 410 (410a, 410b, 41).
0c), passes through the paper discharge path 413, and is fed from the paper discharge roller pair 406 to the folding device 500 at the next stage.

A full load detection sensor 421 is arranged above the buffer tray 403. This full load detection sensor 421
Detects a sheet when the uppermost surface of the sheets stacked in the buffer tray 403 reaches P ′.

FIG. 3 shows the buffer module 4 of this embodiment.
10 is a block diagram showing the configuration of a control circuit 900 that controls 00. The control circuit 900 is a microprocessor (hereinafter C
PU) 901 is mainly configured, and the CPU
Drive circuits and sensor signals of various loads are connected to the input / output port of 901.

Further, the control circuit comprises a RAM 904 used as an area for temporarily holding control data, a work area for calculation accompanying control, and a ROM 903 storing control sequence software. In addition, communication IC9
Reference numeral 02 denotes a communication IC for controlling data communication with the image forming apparatus controller 906 and the finisher controller 905.

The inlet motor 433 is driven by the driver 443. An excitation signal and a motor current control signal are input from the CPU 901 to this driver. The separation motor 434 and the paper discharge motor 435 are also driven by the driver 44
4, 445 are driven by receiving an input signal from the CPU 901. The inlet solenoid 431 and the paper discharge solenoid 432 are driven by drivers 441 and 442, respectively.
The operations of all the drivers 441 to 446 are controlled by a signal connected to the output port of the CPU 901.

Further, the entrance sensor 414 and the paper discharge sensor 4
15, paper presence / absence detection sensor 416, separation sensor 417,
Various sensors such as the full load detection sensor 421 are the CPU 901.
Connected to the input port of the buffer module 4
00 is used to control the paper inside and the drive load.

The operation of the buffer module 400 of this embodiment will be described based on the buffer module chart of FIG.

After the buffer module 400 of FIG. 2 is powered on (main1), the buffer module 400 performs an initialization operation. At this time, at the same time, the image forming apparatus 1 of FIG.
000, folding device 500, and finisher main body 600
The initialization operation of is also performed. After the initialization operation, if the buffer module 400 can operate normally (main2),
Wait until the operation starts (main4). If it cannot operate at this time, an error is notified to the image forming apparatus 1000 (main3).

When the image forming start signal of the image forming apparatus 1000 is detected, the image forming apparatus 1000 and the folding apparatus 500 are detected.
The processing capability information (described later) and the operation mode (described later) regarding the finisher main body 600 are the communication IC 902 of FIG.
Is detected by the CPU 901 via (main
5). The CPU 901 of the buffer module 400 calculates the processing capacities (described later) of the image forming apparatus 1000, the folding device 500, and the finisher main body 600 from the processing capacity information (main6).

Here, when the processing capacity of the folding device 500 and the finisher main body 600 is higher than that of the image forming apparatus 1000, or when the processing capacities of both are equal (ma).
in7), through-pass processing (m
It is controlled by ain9). If the processing capacity of the image forming apparatus 1000 is higher than that of the folding device 500 and the finisher main body 600, control (main8) using a buffer path described later is performed.

After the series of sheet carrying processing is performed, the image forming in the image forming apparatus 1000 is completed and the paper carrying processing in the buffer module 400 is finished (main1).
0), the buffer module 400 ends the operation (m
ain11).

(Acquisition of Processing Capacity Information and Operation Mode) The processing capacity information and operation mode described above will be described in detail <(main4) of FIG. 4>.

The buffer module 400 shown in FIG. 1 includes the image forming apparatus 1000 and the folding apparatus 50 connected to the front and rear of the buffer module 400.
0 and the finisher main body 600, the processing capability information and the operation mode of the post-processing device are transmitted to the CP via the communication IC 902.
Obtained at U901 (main5).

At this time, the processing capacity information obtained from the image forming apparatus 1000 is the sheet discharging speed, the sheet discharging interval, the sheet size to be discharged, and the number of discharged sheets. Further, the processing capacity information obtained from the folding device 500 and the finisher main body 600 side is the sheet receivable speed, the sheet receivable size, and the sheet receivable interval.

As the operation mode, the CPU 901 of FIG. 3 has information as to whether the image forming apparatus 1000 forms an image on a sheet on one side or on both sides, and the folding apparatus 50.
0 and information about functions used in the finisher main body 600 are acquired. The buffer module 400 performs a series of operations called a job by combining the operation modes.

(Calculation of Processing Capacity) The calculation of the processing capacity described above will be described in detail <(main6) of FIG. 4>.

CPU of the buffer module 400 of FIG.
901 is the image forming apparatus 1000 obtained by (main5)
The image forming apparatus 1000, the buffer module 400, the folding device 500, and the finisher main body 6 based on the processing capacity information of the folding device 500 and the finisher main body 600.
The processing capacity of each of 00 is calculated (main
6). Here, the processing capacity is defined by the number of sheets of paper that can be processed by the apparatus per unit time.

The processing capability of the image forming apparatus 1000, the folding apparatus 500, and the finisher main body 600 is high or low. The CPU 9 shown in FIG.
01 judges. The CPU 901 adjusts the sheet receiving speed and the sheet discharging speed of the buffer module 400 so that the processing capability of the image forming apparatus 1000 does not drop when the folding apparatus 500 and the finisher main body 600 are connected to the image forming apparatus 1000.

(Through Pass Processing) The through pass processing operation (main9) of the buffer module 400 will be described based on the through pass processing chart of FIG.

When the CPU 901 in FIG. 3 determines that the processing capacity of the image forming apparatus 1000 is slower than that of the folding device 500 and the finisher main body 600 (through 2) due to the start of operation (through 1), the image forming operation of the image forming apparatus 1000. Simultaneously with the start, the inlet solenoid 431 and the sheet discharge solenoid 432 of FIG. 3 are turned off, and the sheet can be conveyed by the through path 411 of FIG. 2, so that the inlet switching flapper 401 and the outlet switching flapper 402 of FIG. 2 are switched. (Through3).

At this time, the sheet discharge speed of the image forming apparatus 1000 and the buffer module 40 are calculated from the processing capacity information.
0 sheet receiving speed and buffer module 400
The rollers in the buffer module 400, which will be described later, are controlled and rotated so that the sheet discharge speeds from the sheets are all equal.

When the buffer module 400 receives a sheet from the entrance roller pair 404 that rotates in accordance with the sheet ejection speed from the image forming apparatus 1000, the conveyance roller pair 4
The sheets 05a, 405b, and 405c are rotated to convey the sheet to the discharge roller pair 406. When the leading edge of the sheet conveyed in the through path 411 of FIG. 2 is detected by the sheet discharge sensor 415, the pair of sheet discharging rollers 406 that rotates according to the speed of the sheet discharged from the image forming apparatus 1000 causes the folding device 500 to rotate. And it is carried out to the finisher main body 600 (through 4). At this time, the folding device 500 and the finisher main body 600 perform the processing operation in accordance with the sheet conveyance speed at which the image forming apparatus 1000 can operate and the sheet interval.

After that, it is judged whether the job from the image forming apparatus 1000 is completed (through 5), and if there is a sheet to be continued, the process returns to (through 4), and if the operation is completed, the process proceeds to (through 6).

(Buffer Path) Based on the buffer path processing chart of FIG. 6, the buffer path processing operation (main)
8) will be described.

After the operation is started (buff1), the CPU 901 in the buffer module 400 causes the image forming apparatus 100 to operate more than the folding device 500 and the finisher main body 600.
When it is determined that the processing capacity of 0 is fast (buff2) and the image forming start signal of the image forming apparatus 1000 is detected, the inlet solenoid 431 and the sheet discharge solenoid 432 of FIG. 3 are turned on, and the inlet switching flapper 401 of FIG. The outlet switching flapper 402 is switched, and the inlet path 412, the buffer tray 403, and the paper discharge path 413 are made effective (buff).
3).

In the buffer module 400, the sheet conveyed from the image forming apparatus 1000 is received by the pair of inlet rollers 404 shown in FIG.
The paper is conveyed to 2. The transport roller 407 whose tip is detected by the entrance sensor 414 starts to rotate, but the sheet transported to the buffer tray 403 by the transport roller 407 drops in the buffer tray 403 and is stacked (sheet P shown in FIG. 2). (Buff4).

The stack of sheets P thus stacked is based on the processing capacity information of the folding device 500 and the finisher main body 600, and the buffer module 400 and the folding device 500.
Also, the separation roller 408 and the half-moon roller 409 separate sheets one by one from the bottom at intervals such that sheets can be delivered between the finisher main body 600 (buf).
f5).

When the separation sensor 417 detects the leading edge of the sheet separated from the lower layer of the buffer tray 403, the pair of conveying rollers 410a, 410b, 41 in the sheet discharge path 413.
0c rotates so as to convey the separated sheets toward the folding device 500 and the finisher main body 600. When the leading edge of the sheet conveyed in the sheet discharge path 413 is detected by the sheet discharge sensor 415, the sheet discharge roller pair 406 that rotates at the receivable speed of the folder 500 and the finisher main body 600 causes the sheet to be folded. And to the finisher main body 600 (buff
5).

If the paper to be subsequently separated is in the buffer tray 403, the separation process is repeated (bu
ff7) If there is no sheet to be separated, then it is confirmed whether the sheet to be processed is carried into the buffer tray 403 (buff8).

At this time, the sheet stacking process (buff4) on the buffer tray 403 and the sheet transporting processes (buff5), (buff6), and (buff7) to the post-processing device are operated independently of each other to form an image. Device 1
It is possible to process the folding device 500 and the finisher main body 600 without lowering the processing capacity of 000. (Buf
When there is no more paper to be processed in the buffer tray 403 at f8), the buffer module 400 ends the operation (buff9).

(Explanation of control when the loading tray and buffer module are fully loaded) The control when the loading tray and buffer module are fully loaded will be described with reference to FIGS.

In FIG. 7, a stack of sheets P10 conveyed from the buffer module 400 to the stack tray 700.
0 is loaded. Stack tray area sensor 72
Reference numeral 1 denotes a sensor that detects the vertical position of the stack tray 700, and a sensor that detects the lower limit position of the stack tray 700, that is, the maximum number of sheets that can be stacked on the stack tray 700.

Similarly, a sheet bundle P200 carried in from the image forming apparatus 1000 is stacked on the buffer tray 403. As described above, the full load detection sensor 42
1 is arranged above the buffer tray 403, and the upper limit of the number of sheets that can be stacked on the buffer tray 403 is detected.

FIG. 8 is a diagram showing a control flow when the loading tray and buffer joule are fully loaded. First, the CPU 901
However, it is determined from the information of the full load detection sensor 421 whether the buffer tray 403 is full (S101).

If not fully loaded at this time, the image forming apparatus 10
The sheet discharge from 00 is permitted (S104), and the sheet is carried into the buffer tray 403 (S105).

As described above, the post-processing device 200
When the processing capacity of 0 is lower than that of the image forming apparatus 1000, the buffer tray 403 in the buffer module 400 is full. At this time, the CPU 901 prohibits image formation in the image forming apparatus 1000 through the communication IC 902 (S10
2) Output a signal. Then, the image forming apparatus 1000 displays an alarm on the display unit such as the operation unit that the buffer modules are full (S103). After that, when the full load detection sensor 421 detects the full load release, the CPU 90
1 outputs the prohibition release to the image forming apparatus 1000 through the communication IC 902, and the restart of image formation starts.

After the sheets are carried into the buffer tray 403 (S105), it is judged whether or not the stack tray 700 is full (S106).
The sheet conveyance to the stack tray 700 is sequentially permitted from 3 (S109). If it is determined in S106 that the stack tray is full, conveyance to the stack tray 700 is prohibited (S10
7), the CPU 901 passes the communication IC 902, and the image forming apparatus 1000 displays the stack tray 7 on the display unit such as the operation unit.
An alarm is displayed to indicate that 00 is full (S10
8). At this time, since the buffer tray 403 is not full, image formation is continued.

When the operator removes the sheet bundle P100 from the stack tray 700, the transfer from the buffer tray 403 to the stack tray 700 is permitted as described above.

[0073]

As described above, according to the present invention, since the buffer module is arranged between the image forming apparatus and the post-processing apparatus, even if the stacking tray of the post-processing apparatus is full, the image forming is performed in the buffer module. Since the sheets discharged from the apparatus can be stored, the processing capacity of the image forming apparatus can be maintained regardless of the processing capacity of the post-processing apparatus.

[Brief description of drawings]

FIG. 1 is an internal configuration of an image forming system.

FIG. 2 is a configuration of a buffer module.

FIG. 3 is a hardware block diagram of a buffer module.

FIG. 4 is a buffer module chart.

FIG. 5 is a through-pass processing chart.

FIG. 6 is a buffer pass processing chart.

FIG. 7 shows a configuration in which the loading tray is fully loaded.

FIG. 8 is a control flow when a load is full.

[Explanation of symbols]

400 buffer module 403 buffer tray 421 Buffer tray full load detection sensor 700 stack tray 721 Stack tray area sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C061 AP01 AP04 AQ06 AS02 HJ04                       HK11 HN18                 2H072 AA07 AA17 AA28 BB08 CA01                       CB01 GA01 GA02 GA08                 3F048 AA02 AA05 AB01 BA04 BB02                       CB04 CC17 DA03 DA09 DB11                       DC10 DC14 EA03                 3F054 AA01 AB01 AC02 AC05 BA02                       BB05 BD02 BJ02 BJ04 CA12                       CA23 CA32

Claims (2)

[Claims] 1. A sheet post-processing apparatus for post-processing a sheet discharged from an image forming apparatus for forming an image,
A buffer module device that temporarily stores the sheets discharged from the image forming apparatus, a first full-load detection unit that detects whether or not the sheets stored in the buffer module device are full, and the sheet is conveyed from the buffer module device. It has a stacking means for stacking the sheets, and a second full load detecting means for detecting a full load of the stacking means, the second full load detecting means judges that the stacking means is full load, and the first full load detecting means. When the full-load detection means determines that the buffer module device is not full, the sheet conveyance from the buffer module device to the stacking means is interrupted, and the first full-load detection means detects the full load of the buffer module device. , A control for controlling the sheets discharged from the image forming apparatus to be continuously discharged to the buffer module apparatus. Sheet post-processing apparatus buffer module device is connected, characterized in that it comprises means. 2. When the operator removes the sheets from the stacking means and determines that the second full load detecting means is no longer full, the sheet conveyance from the buffer module device to the stacking means is restarted. The sheet post-processing apparatus according to claim 1, further comprising control means for controlling.