JP4968472B2 - Paper discharge device - Google Patents

Description

  The present invention relates to a paper discharge device that includes a plurality of mechanically detachable paper discharge trays and can discharge paper on which an image has been formed to an arbitrary paper discharge tray.

As a device that discharges paper on which image formation has been performed in the image forming apparatus, it is possible to set and output the address for each person who wants to discharge for each discharge bin as a sorter that discharges paper as sort and applied technology of the sorter Mail bin sorters are known. These apparatuses are provided with a plurality of paper discharge trays, and the paper discharge trays are usually detachable mechanically (see Patent Documents 1 and 2).
In Patent Document 1, a plurality of partition plates are provided as a paper discharge tray, and the size of the apparatus can be avoided by allowing the partition plates to move. Further, in Patent Document 2, it is assumed that a detection means for detecting the full load of paper in the paper discharge tray and a detection means for detecting the attachment / detachment of the paper discharge tray are provided, and both are used by moving the detection means. Prevents accidental discharge to the detached sheet.
JP 58-1335060 A JP 2006-290540 A

  By the way, in a device that discharges paper, there is a space limitation on the amount of paper that can be discharged and stacked on the paper discharge tray, so it is difficult to discharge a paper amount that exceeds this limit to the paper discharge tray. However, recently, there is a demand for discharging a large amount of paper at a time, and it is required to enable a large amount of paper discharge without being restricted by the space of the paper discharge tray. In response to this, it is conceivable that a large amount of paper can be discharged by removing a part of the paper discharge tray and discharging the paper to the adjacent paper discharge tray. However, this method requires the operator to manually remove the paper discharge tray, set the paper discharge destination, etc., which is troublesome and reduces productivity. . In the conventional paper discharge device, no means has been taken to meet the above requirements, and the above-mentioned problems naturally occur in the devices proposed in Patent Documents 1 and 2. In particular, in Patent Document 2, it is difficult to realize the above-described operation for preventing a large number of sheets from being ejected to the removed sheet ejection tray. In addition, in the detection of attachment / detachment of the paper discharge tray proposed in Patent Document 2, a mechanism for moving the detection means is necessary, and there is a problem that the apparatus becomes complicated.

  The present invention has been made against the background of the above circumstances, and a basic object of the present invention is to provide a paper discharge device that can detect the attachment and detachment of the paper discharge tray without requiring a complicated device. And Furthermore, an object of the present invention is to provide a paper discharge device that can automatically perform a large amount of paper discharge with the paper discharge tray removed.

  That is, in the present invention, the paper discharge device according to the first aspect of the present invention is a paper discharge device having a plurality of mechanically detachable paper discharge trays. A full tray detection sensor for detecting a full tank and a zero tray detection sensor for detecting zero sheets in the paper discharge tray itself, and a detection result by the full tray detection sensor and the full tray detection sensor Control means for determining attachment / detachment of the paper discharge tray provided with the tray full sensor based on the detection result of the zero-sheet detection sensor provided in the adjacent paper discharge tray itself to be detected. It is characterized by.

The paper discharge device according to a second aspect of the present invention is characterized in that, in the first aspect of the present invention, the attachment / detachment determination of the paper discharge tray is made by sensor logic.

According to a third aspect of the present invention, in the first aspect of the present invention, the tray full sensor that is provided in the Nth discharge tray is configured so that the N-1th discharge tray is adjacent to the tray full sensor. The sensor detects a full sheet, and the control means detects that the Nth discharge tray is removed when a discharge to the discharge tray is required exceeding a normal full tank amount in the discharge tray. When the determination is made, paper is discharged from the discharge position with respect to the Nth discharge tray detected to be detached, with the (N-1) th discharge tray as the discharge destination, and the Nth discharge tray is full. The role of the tray full detection sensor provided in the (N + 1) th discharge tray for detecting the tank is changed to the tray full detection sensor for detecting the paper full in the (N-1) th discharge tray. Features.

According to the fourth aspect of the present invention, in the first to third aspects of the present invention, when it is determined that the paper discharge tray is removed, a warning is given when there is an instruction to use the paper discharge tray as a paper discharge destination. It is characterized by doing.

  According to the present invention, the attachment and detachment of the paper discharge tray is performed using the detection result of the tray full sensor for detecting the full paper in the paper discharge tray and the tray 0 sheet detection sensor for detecting 0 paper in the paper discharge tray. Can be detected. Accordingly, it is possible to detect attachment / detachment of the discharge tray without preparing a special sensor for detecting attachment / detachment of the discharge tray.

  The tray full detection sensor and the zero tray detection sensor can transmit the detection result to the control unit by sensor logic, and the control unit can determine whether the paper discharge tray is attached or detached according to the sensor logic. For example, if zero sheet detection and full tank detection are performed simultaneously for the same paper discharge tray, the results are inconsistent, and in this case, it can be determined that the paper discharge tray has been removed.

  When the paper discharge tray is removed, the paper can be stacked on the closest paper discharge tray in the attached state by discharging the paper through the paper discharge section of the paper discharge tray. A large amount of paper can be discharged without being limited by the arrangement space.

  For example, when paper is discharged from the discharge position of the removed Nth discharge tray toward the (N-1) th discharge tray, the discharge to the discharge tray exceeds the normal full tank amount. It becomes possible to do. However, in this case, if the full tank detection sensor provided in the Nth discharge tray detects that the N−1th discharge tray is full, the Nth discharge tray is removed. , It is not possible to detect full paper in the (N-1) th paper discharge tray. In this case, a full tank detection sensor that is provided in the (N + 1) th paper discharge tray and originally detects a full tank of the Nth paper discharge tray detects full paper in the (N-1) th paper discharge tray. By switching the roles so as to perform, it becomes possible to continue to detect full tank even when the paper discharge tray is removed. The role is changed by a control unit that receives the detection result of the sensor and determines whether the paper discharge tray is attached or detached. In the (N-1) th discharge tray, paper exceeding the normal full tank amount is discharged and discharged until the full tank detection sensor provided in the (N + 1) th discharge tray detects a full tank. It can be carried out.

  As described above, according to the paper discharge device of the present invention, in a paper discharge device having a plurality of mechanically detachable paper discharge trays, Since these sensors are provided with control means for determining whether or not the discharge tray to be detected is attached or not based on detection results of the tray full detection sensor to detect and the detection result of the zero tray detection sensor for detecting zero sheets in the discharge tray. Thus, the attachment / detachment of the paper discharge tray can be automatically detected without requiring special use of the attachment / detachment detection sensor.

  The tray full sensor for the Nth paper discharge tray is a sensor for detecting the paper full in the N−1th paper discharge tray adjacent to the Nth paper discharge tray. If it is determined that the Nth paper discharge tray is removed when the normal full tank amount is exceeded and it is determined that the Nth paper discharge tray is removed, the N−1th paper discharge tray is moved to the paper discharge destination. As described above, the sheet is discharged from the discharge position with respect to the Nth discharge tray detected to be detached, and is provided in the (N + 1) th discharge tray to detect the fullness of the Nth discharge tray. If the role of the tray full detection sensor is changed to the tray full detection sensor for detecting the paper full in the (N-1) th paper discharge tray, the paper discharge position for the removed paper discharge tray is used. Larger than normal paper full capacity The enabling of the discharge paper, and further, regardless of the removal of the discharge tray, it is possible to detect the full paper in neighboring discharge tray.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
The paper discharge apparatus 10 of the present invention having a plurality of paper discharge trays is connected to the image forming apparatus 1 that forms an image on paper based on image data, and can carry the paper from the image forming apparatus. In addition, bidirectional communication is possible between the image forming apparatus and the paper discharge apparatus 10.
Note that the paper discharge device of the present invention is independent of the image forming apparatus and the post-processing apparatus as in this embodiment, and is incorporated in the image forming apparatus and the post-processing apparatus in addition to those used by being connected to them. It may be used as a product.

  The image forming apparatus 1 includes an image forming control unit 2 that controls the image forming apparatus 1. The image forming control unit 2 includes a CPU (not shown), a program that operates the CPU, and a ROM that stores the program. The RAM is a work area.

  The image forming control unit 2 is connected to a storage unit 3 formed of a non-volatile memory such as a flash memory so that data can be read and written as appropriate. The storage unit 3 stores operation setting data for the image forming apparatus 1 and the paper discharge apparatus.

  Further, the image forming apparatus 1 includes a main body display unit 6 capable of displaying characters and images. The main body display unit 6 is controlled by the image forming control unit 2 to display necessary information as appropriate. The main body display unit 6 can also be used as an operation unit, and can input machine settings, job settings, job execution commands, and the like of the image forming apparatus 1 through the main body display unit 6.

Next, details of the paper discharge device 10 will be described with reference to FIGS.
The paper discharge device 10 includes a control unit 10a that controls the entire paper discharge device as a control unit, and can control various types of the paper discharge device in response to an instruction from the image forming control unit 2. The control unit 10a includes a CPU 10b, a program for operating the CPU, a ROM (not shown) for storing the program, a RAM (not shown) serving as a work area, and the like.
In this embodiment, as described above, the control unit of the present invention is described as being installed in the paper discharge apparatus main body. However, the image forming control unit on the image forming apparatus side may be configured to play a part. It is.

  Further, in the paper discharge device 10, a fixed paper discharge tray 11 and mechanically detachable discharge trays 12 to 20 are arranged in parallel at equal intervals obliquely upward. The paper discharge device 10 is provided with a paper discharge path 25, and the front end side of the paper discharge path 25 is a distribution path 25 a that extends horizontally from the vicinity of the entrance of the paper discharge tray 11 to the vicinity of the entrance of the paper discharge tray 20. It is arranged along the direction.

  Further, on the side of the paper discharge trays 10 to 20 near the distribution path 25a, guide plates 30 ... 30 corresponding to the respective paper discharge trays 11 to 20 are rotated by a rotation shaft along the width direction of the distribution path 25a. Arranged to be possible. The guide plates 30... 30 are located between the guide plates 30... 30 and the distribution path 25a because the lower surface on the side of the distribution path 25a is always along the distribution path 25a and has a gap with the distribution path 25a. The paper can be moved. On the other hand, when any of the guide plates 30... 30 rotates counterclockwise in the figure, any of the rotated guide plates 30... 30 intersects the distribution path 25a, and the sheet conveyed through the distribution path 25a is guided by the guide plate. The sheet is moved to the sheet discharge tray side along the upper surface side of the sheet 30 and guided to the sheet discharge trays 11 to 20 corresponding to the respective guide plates 30.

  Each of the paper discharge trays 11 to 20 is provided with a zero-tray detection sensor 21 on the stacking surface side that is introduced into the paper discharge tray and on which paper is stacked. The zero-sheet detection sensor 21 includes a detection piece 21a that moves from the initial position when the sheets are stacked and returns to the initial position when the sheets are not stacked. The detection piece 21a partially protrudes from the stacking surface when no sheets are stacked on the stacking surface of the paper discharge tray. When the sheets are stacked on the stacking surface, the protruding part is determined by the mass of the sheet. Move to the loading surface. The 0-tray detection sensor 21 has a photo interrupter 21b that turns on when the detection piece 21a moves to the stacking surface by stacking sheets. As shown in FIG. 3, the output of the photo interrupter 21b is output to the CPU 10b of the control unit 10a. That is, in a state where no sheets are stacked (detecting 0 sheets), the 0-tray detection sensor 21 is not turned on, and a Hi signal is input to the CPU 10b based on the power supply voltage. In a state where sheets are stacked on the paper discharge tray (zero sheet non-detection), the zero-sheet detection sensor 21 is turned on, and the input to the CPU 10b is a Lo signal.

  In addition, a tray full sensor 22 is provided on the back side of each of the paper discharge trays 12 to 20 (on the opposite side of the paper stacking surface) to detect the fullness of the paper stacked on the adjacent paper discharge tray. It has been. The tray full detection sensor 22 moves a detection piece 22a that moves from the initial position when the upper surface of the paper stacked on the discharge tray on the back side reaches the full position, and returns to the initial position when the full state is not reached. I have. A part of the detection piece 22a is located closer to the stacking surface than the full sheet position when the number of stacked sheets is small or zero, and as the stacked sheets approach full, Move in the thickness direction of the paper. The tray full sensor 22 is turned off when the paper stacked on the paper discharge tray has not reached the full tank position. When the stacked paper reaches the full tank position, the detection piece 22a is moved. The photo interrupter 22b is turned off. The output of the photo interrupter 22b is output to the CPU 10b as shown in FIG. In other words, when the paper is full on the back side discharge tray (full tank detection), the tray full sensor 22 is turned off and a Hi signal is input to the CPU 10b by the power supply voltage. In a state where the paper is not full (no full detection), the tray full detection sensor 22 is turned on and a Lo signal is input to the CPU 10b. The tray full sensor 22 for the paper discharge tray 20 is provided on the main body side of the paper discharge device, and can detect full paper in the paper discharge tray 20.

  Table 1 shows the detection results of the zero-sheet detection sensor 21 provided in the paper discharge tray and the tray full detection sensor 22 provided in the adjacent paper discharge tray for a certain paper discharge tray. It becomes the combination shown in. H and L in the table indicate Hi signals or Lo signals given to the CPU 10b.

Next, the operation of the paper discharge device 10 will be described.
In the image forming apparatus 1, job setting and job start are performed by an operation on the main body display unit 6, and image formation on a sheet is performed using image data acquired by reading a document based on the job setting. The job setting includes information on the position of the discharge tray to the specified discharge tray. A series of these operations is controlled by the image formation control unit 2.

  The paper on which the image has been formed is transported from the image forming apparatus 1 to the paper discharge device 10 by a transport device (not shown). The paper discharge tray position information and the like are notified to the control unit 10a of the paper discharge device 10 by the image formation control unit 2. The paper is sent to the paper discharge device 10 based on the notified information. In conveying the sheet to the sheet discharge device 10, the sheet is conveyed to the distribution path 25 a through the sheet discharge path 25. In the control unit 10a of the paper discharge device 10, the guide plate 30 corresponding to the paper discharge tray is rotated based on the paper discharge tray position information notified from the image forming control unit 2 so as to cross the distribution path 25a. . The sheet passing through the paper discharge path 25 and moving on the distribution path 25a is guided to the paper discharge outlets of the respective paper discharge trays 11 to 20 by the guide plate 30 intersecting with the distribution path 25a. Any one of 11 to 20 is assigned. In FIG. 2, a paper discharge port 16a for the paper discharge tray 16 is shown.

  In each discharge tray, zero sheet detection (sensor off) is detected by the tray zero sheet detection sensor 21 as described above, and until the sheet is introduced, the zero sheet is detected and a Hi signal is input to the CPU 10b as sensor logic. When the paper starts to be discharged to a predetermined paper discharge tray, the zero-sheet detection sensor 21 of the paper discharge tray enters a non-detection state (sensor on), and a Lo signal is input to the CPU 10b as sensor logic. .

  In each discharge tray, the full tray detection sensor 22 detects the full state of the adjacent discharge tray on the back side of the sheet stacking surface as described above. Until the tray is full, the tray full sensor 22 is not full (sensor on) and a Lo signal is input to the CPU 10b as sensor logic. When the paper is full in the paper discharge tray, the tray full sensor 22 provided in the next paper discharge tray detects full (sensor off), and a Hi signal is input to the CPU 10b as sensor logic.

When the paper discharge tray is removed from any one of the paper discharge trays 12 to 20, the tray full sensor 22 is turned off in the removed paper discharge tray, and a Hi signal is input as sensor logic to the CPU 10b. A full tank is detected for the adjacent paper discharge tray. FIG. 2 shows a state where the paper discharge tray 16 is removed.
On the other hand, when 0 sheet is detected by the tray 0 sheet detection sensor 21 in the sheet discharge tray (the sheet discharge tray 15 in FIG. 2) that is detected by the tray full detection sensor 22, the tray 0 sheet detection sensor 21 is detected. And the detection result of the tray full detection sensor 22 contradict each other, and the paper discharge tray (the paper discharge tray 16 in the figure) provided with the tray full tank detection sensor 22 indicating the inconsistent detection result is removed. I understand that. The determination can be made based on sensor logic in the control unit 10a.

Further, when sheets are stacked on the discharge tray 15 to be detected by the tray full detection sensor 22, the detection result of the tray full detection sensor 22 is not full when the discharge tray 16 is removed. Since it changes from detection to a full tank detection state or is only in a full tank detection state, it is difficult to detect removal of the paper discharge tray depending on this change.
Therefore, the attachment / detachment determination of the discharge tray by the sensor logic is performed when zero sheet detection is performed on the discharge tray targeted by the tray full detection sensor 22.

Next, a paper discharge control procedure according to attachment / detachment of the paper discharge tray will be described based on the flowchart of FIG.
The operation is started when the image forming apparatus 1 and the paper discharge apparatus 10 are powered on (step s1). In the control unit 10a, detection results of the zero-sheet detection sensor 21 and the tray full detection sensor 22 in each paper discharge device are input as the operation starts. Here, in the control unit 10a, a tray full detection sensor 22 (N-th sheet discharge) for the stacked sheets on the (N−1) -th (N = 2... 10) sheet discharge tray (sheet discharge tray 11... 19). It is determined whether or not the full tank detection is in the detection state (assumed to be provided in the tray) (step s2). If it is detected by the tray full sensor 22 that the tray is full (NO in step s2), it is determined that the N-th sheet discharge tray has arrived since the sensor full state of the tray full sensor 22 is recognized (step S2). Step s13). Next, it is determined whether or not zero sheet is detected by the zero-sheet detection sensor 21 (provided in the (N-1) th sheet discharge tray) in the (N-1) th sheet discharge tray (step s14). In this determination, if 0 sheet is detected (step s14, YES), it is determined that there is no paper in the (N-1) th tray (step s15), and if 0 sheet is not detected (step s14, NO), N-1 It is determined that there is paper in the th tray (step s16), and in either case, the paper is normally discharged to the (N-1) th paper discharge tray (step s17), and the process ends.

  On the other hand, if it is determined in the determination (step s2) that the full tray detection sensor 22 for the (N-1) th discharge tray is full (step s2, YES), the (N-1) th is continued. It is determined whether or not zero sheets are detected by the zero-sheet detection sensor 21 in the sheet discharge tray (step s3). When 0 sheets are not detected (step S3, NO), there is no contradiction in the detection results for the (N-1) th sheet discharge tray, the Nth sheet discharge tray is in the arrived state, and the (N-1) th sheet discharge tray. It is determined that the paper discharge tray is full. Thereafter, the paper discharge is stopped and the process is terminated (step s10).

  On the other hand, if it is determined in the above determination (step s3) that the 0th tray detection sensor 21 detects 0th sheet of the (N-1) th sheet discharge tray (YES in step S3), the N-1th sheet discharge. Since the detection results of the zero-sheet detection sensor 21 and the tray full detection sensor 22 for the tray contradict each other, it is determined that the Nth discharge tray is in a removed state (step s4). After this determination, the tray full detection sensor provided in the (N + 1) th discharge tray detects the fullness of the paper in the Nth discharge tray. The role is changed to what is detected (step s5).

  Based on the determination, the control unit 10a notifies the image forming control unit 2 of the image forming apparatus 1 that the Nth paper discharge tray has been removed (step s6). Next, it is determined whether or not the instruction information of the discharge tray indicates the Nth discharge tray (step s7). If the Nth discharge tray is specified, the image forming apparatus 1 forms an image. The control unit 2 is notified (warning). In the image forming apparatus 1, paper discharge to the paper discharge tray is prohibited, and discharge prohibition is displayed on the display unit 6 or the like (step s11).

If it is not an instruction to discharge to the Nth discharge tray in the determination (step s6), it is determined whether or not it is an instruction to discharge to the (N-1) th discharge tray (step s8). Here, if it is not an instruction to discharge to the (N−1) th discharge tray (step s8, NO), normal discharge is performed to the specified Nth and N−1th discharge trays (step s12). ), The process is terminated.
If the above determination (step s8) is an instruction to discharge to the (N-1) th discharge tray (step s8, YES), the discharge position on the Nth discharge tray (in the discharge tray 16 in FIG. 2). Paper is discharged from the paper discharge port 16a). As a result, the discharged sheets are sequentially stacked on the (N-1) th discharge tray (step s9), and a large amount of sheets exceeding the full tank amount of the normal discharge tray can be discharged. Further, in step 5, the tray full sensor 22 for detecting the fullness of the paper loaded on the Nth paper discharge tray detects the fullness of the paper loaded on the (N-1) th paper discharge tray. Since the role of the sensor has been changed, the full capacity of the sheets sequentially stacked on the (N-1) th discharge tray is set to the normal full amount even when the Nth discharge tray is removed. It becomes possible to detect with the full tank amount exceeding.

  In the above embodiment, the paper full of the paper discharge tray is performed by the tray full sensor that is provided in the adjacent paper discharge tray, and the zero sheet detection is performed by the tray 0 sheet detection sensor that is provided in the paper discharge tray itself. However, both detections can be performed by the tray full detection sensor and the zero tray detection sensor provided in the paper discharge tray itself.

FIG. 5 is a view showing a side surface (a diagram) and a plan view (b diagram) of the sheet discharge tray 40 provided with the zero-sheet detection sensor 41 and the tray full detection sensor 42. The paper discharge device is provided with a plurality of paper discharge trays having the same configuration.
The tray 0 sheet detection sensor 41 has a detection piece 41a that partially protrudes on the sheet stacking surface in a state in which no sheets are stacked, and moves to the stacking surface when the sheet is stacked, and a photo interrupter 41b. It has. The photo interrupter 41b is turned off when the detection piece 41a is moved to the stacking surface by stacking sheets, and is turned on when the detection piece 41a is not stacked and a part of the detection piece 41a protrudes on the stacking surface.

On the other hand, the tray full tank detection sensor 42 includes a detection piece 42a that is partially located near the full tank position on the sheet stacking surface and moves in the sheet thickness direction as the sheets are stacked, and a photo interrupter 42b. ing. The photo interrupter 42b is in a sensor-on state until the paper stacked on the paper discharge tray 40 reaches the full tank position. When the paper reaches the full tank position, the sensor is turned off by the detection piece 42a that moves accordingly. . The zero tray detection sensor 41 and the tray full detection sensor 42 are connected to the CPU 10b of the control unit 10a in the same manner as in the above-described embodiment, so that Lo or no depending on the presence or absence of paper in the discharge tray 40. The Hi signal is given to the CPU 10b. The detection result by each sensor and the signal given to the CPU 10b are the same as those in Table 1. In this reference example , when the paper discharge tray 40 is pulled out, a full tank detection and a zero-sheet detection state are entered, so that contradictory detection results occur, and it is determined in the control unit 10a that the paper discharge tray 40 has been pulled out. It becomes possible.

  The present invention has been described based on the above embodiment, but the present invention is not limited to the content of the above embodiment, and can be appropriately changed without departing from the scope of the present invention. It is.

1 is a partial cross-sectional view illustrating a paper discharge device according to an embodiment of the present invention. It is sectional drawing which expanded and showed a part similarly. Similarly, it is a figure which shows the connection of a sensor and a control part. Similarly, it is a flowchart showing a paper discharge control procedure. It is the schematic which shows the paper discharge tray in a reference example .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image formation control part 6 Display part 10 Paper discharge apparatus 10a Control part 11 ... 20, 40 Paper discharge tray 21, 41 Tray 0 sheet detection sensor 22, 42 Tray full detection sensor

Claims (4)

  In a paper discharge device having a plurality of mechanically detachable paper discharge trays, each of the paper discharge trays includes a tray full detection sensor that detects a paper full state of an adjacent paper discharge tray, and the paper discharge tray itself. A zero-tray detection sensor that detects zero sheets, and the detection result of the tray full-tank detection sensor and the detection of zero-trays provided on the adjacent paper discharge tray itself that is detected by the tray-full-tank detection sensor. A paper discharge device, comprising: a control unit that determines attachment / detachment of a paper discharge tray provided with the tray full detection sensor based on a detection result of the sensor. The paper discharge device according to claim 1, wherein the attachment / detachment determination of the paper discharge tray is made by sensor logic. The tray full detection sensor provided in the Nth paper discharge tray is a sensor for detecting the paper full in the N−1th paper discharge tray adjacent to the Nth paper discharge tray. If it is determined that the Nth discharge tray is removed when the normal full tank amount needs to be discharged to the discharge tray, the N-1th discharge tray is set as the discharge destination. The paper is discharged from the discharge position with respect to the Nth discharge tray detected to be detached, and the trays provided in the (N + 1) th discharge tray are full in order to detect the fullness of the Nth discharge tray. 2. The paper discharge device according to claim 1, wherein the role of the tank detection sensor is changed to a tray full tank detection sensor for detecting a paper full in the (N-1) th paper discharge tray. 4. The control unit according to claim 1, wherein when the discharge tray is determined to be removed, the control unit warns when there is an instruction to set the discharge tray as a discharge destination. Paper discharge device.

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