JP2000281258A - Sheet loading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a proper stacking property by preventing a face curl from being caught into a paper discharge roller, etc., even the face curl is produced on a sheet. SOLUTION: This device is switched into 'a control mode based on a sheet condition' where a paper discharge tray 6 is lowered until a censor 46 is turned OFF, to increase the loading quantity of a paper sheet 75 to turn a sensor 44 OFF for a fixed time. In this control, a parted distance, between the upper surface of the paper sheet 75 and a return roller 39, is made larger than predetermined distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., and a sheet stacking apparatus such as a paper post-processing apparatus attached to the image forming apparatus.

In this type of sheet stacking apparatus, for example, FIG.
As shown in FIG. 3, the height of the upper surface of the sheet (sheet) 105 discharged from the sheet discharge means 102 having the discharge roller 100 and the like and stacked on the discharge tray 104 is determined by the detection lever 106 and the sensors 108 and 110. The upper surface of the sheet is maintained at a substantially constant height by detecting the sheet upper surface height detecting means, and lowering the sheet discharge tray 104 by a predetermined amount by an elevating means (not shown). Things are known. In FIG. 13, reference numeral 112 denotes a sheet 105
2 shows a return roller for aligning the trailing end of the sheet. More specifically, when the sensor 110 is turned on by being blocked by the fan-shaped blocking portion 106a of the detection lever 106 for a certain period of time, the discharge tray 104 is moved a predetermined distance (a predetermined amount). It is designed to descend. The detection lever 106 is provided so as to contact the central portion of the paper 105.

Further, the sheet post-processing apparatus has a staple tray inside the apparatus. After a predetermined number of sheets are stacked and aligned on the staple tray, a binding process is performed, and a bound sheet bundle ( The sheet bundle is discharged to a discharge tray. In such a sheet post-processing apparatus, after a plurality of sheets are stacked and aligned on a staple tray, the sheets may be continuously discharged to a discharge tray in a mere sheet bundle without performing a binding process. Rather than ejecting sheets received from the image forming apparatus one by one to the output tray, stacking and aligning multiple sheets on the staple tray and discharging them collectively improves the stackability on the output tray. Because you can.

[0004]

As shown in FIG.
When the paper 105 is stacked on the paper discharge tray 104 in a so-called face curl state in which the rear end of the paper curls upward, first, the paper 105 is moved between the paper upper surface and the paper discharge roller 100 or the return roller 112 of the sheet discharge means 102. However, since the height is detected at the central portion of the sheet that is not curled, the separation distance is shorter at the curled portion than at the central portion as the number of stacked sheets increases. When the separation distance is lost, the rear end of the uppermost sheet 105 stacked on the sheet ejection tray 104 is moved to the sheet ejection roller 100 or the return roller 1.
12 is involved, and the alignment (stacking) of the paper 105 is deteriorated.

In a sheet post-processing apparatus, when a plurality of unbound sheets are successively discharged to a discharge tray, the sheets stacked on the discharge tray are pushed out by the next discharged sheet bundle. However, there was a problem that good stackability could not be obtained.

Accordingly, an object of the present invention is to provide a sheet stacking apparatus capable of obtaining a good stacking property even when a sheet is discharged in a face curl state. Also,
SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet stacking apparatus capable of obtaining a good stacking property even when a plurality of unbound sheet bundles are continuously discharged to a discharge tray.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a sheet discharge means for discharging sheets, and a discharge tray on which the sheets discharged from the sheet discharge means are stacked. And a raising / lowering means for raising and lowering the sheet discharge tray, and performing control for lowering the sheet discharge tray by a predetermined amount based on the stacking amount of sheets on the sheet discharge tray, so that the upper surface of the sheet is substantially In the sheet stacking apparatus configured to maintain the sheet at a fixed height, when a predetermined amount of the sheet is discharged to the discharge tray, the separation distance between the upper surface of the rear end of the stacked sheet in the discharge direction and the sheet discharge unit is set to The paper ejection tray is lowered so as to be larger than a predetermined amount, and a control mode based on a sheet state is provided.

According to a second aspect of the present invention, there is provided the configuration according to the first aspect, further comprising a control change number setting means capable of arbitrarily setting a certain amount of the sheet.

According to a third aspect of the present invention, in the configuration of the first aspect, there is provided a sheet upper surface height detecting means for detecting the height of the upper surface of the sheets stacked on the discharge tray, and the sheet upper surface height is detected. The control mode based on the sheet state is executed based on the detection information of the detecting means.

According to a fourth aspect of the present invention, in the configuration of the first aspect, there is adopted a configuration in which a separation distance setting means capable of arbitrarily setting the separation distance is provided.

According to the fifth aspect of the present invention, there is provided the first, second, and third aspects.
The configuration according to 3 or 4, wherein a return roller for aligning the trailing end of the discharged sheet is provided, and the separation distance is set based on a lower end of the return roller.

According to the present invention, there is provided a sheet discharge means for discharging sheets, a discharge tray on which sheets discharged from the sheet discharge means are stacked, and an elevating means for raising and lowering the discharge tray. In the sheet stacking apparatus, control is performed to lower the sheet ejection tray by a predetermined amount based on the sheet stacking amount on the sheet ejection tray to maintain the upper surface of the sheet at a substantially constant height. When continuously discharging a plurality of sheet bundles that are not bound to the discharge tray, the discharge tray is raised and stacked on the discharge tray before the sheet discharge unit starts the discharge operation. The rear end of the upper surface of the sheet in the discharging direction is controlled so as to contact the sheet discharging means or the like.

According to a seventh aspect of the present invention, in the configuration of the sixth aspect, the discharge tray is lowered before the sheet bundle passes through the sheet discharge means.

According to the invention described in claim 8, in claim 6 or 7,
In the configuration described above, after discharging a plurality of sheet bundles that are not bound to the discharge tray, before starting the discharging operation of the next plurality of unbound sheet bundles, the discharge direction of the upper surface of the sheet is The apparatus is configured to wait in a state where the end portion does not contact the sheet discharging means or the like, and to perform a sorting operation such as a shift operation in the waiting state.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall schematic diagram of a sheet post-processing apparatus as a sheet stacking apparatus. The sheet post-processing apparatus in this embodiment is attached to a side of a copying machine G as an image forming apparatus. An entrance sensor SN1 is provided at the paper (sheet) transfer portion with the copying machine G, and the leading end and the trailing end of the sheet discharged from the copying machine G are detected. A pair of entrance rollers 4 is provided near the downstream side of the entrance sensor SN1, and the sheet taken in by the pair of entrance rollers 4 is normally discharged in one of the following discharge modes according to the processing mode. . Clear mode: The sheet is discharged from a discharge port E1 to a proof tray P formed on the upper surface of the apparatus. Sort / stack mode: Each sheet is discharged from the discharge port E2 to the discharge tray 6 without performing the binding process. Staple mode: The paper is discharged from the discharge port E2 to the paper discharge tray 6 through a binding process.

The transport route to the proof tray P is switched by a deflecting claw 8 provided on the downstream side of the entrance roller pair 4, the paper is transported by the transport roller pairs 10 and 12, and the proof tray is transported by the paper discharge roller pair 14. It is discharged to P. Reference numeral SN2 indicates a paper ejection sensor. The various roller pairs indicate a combination of a driving roller and a driven roller (the same applies hereinafter). The deflection claw 8 is driven by a solenoid and a spring (not shown), and FIG. 1 shows a state where the deflection claw 8 is guided to the discharge port E2. Downstream of the deflecting claw 8, a deflecting claw 16 for switching between a sorting / stacking route A and a staple route B is provided. Deflection claw 1
Reference numeral 6 is driven by a solenoid and a spring (not shown), and is held at a position indicated by a solid line when guiding the sheet to the sorting / stacking route A, and at a position indicated by a two-dot chain line when guiding the sheet to the staple route B. You. FIG. 1 shows a state of guiding to a route A for sort / stack.

In the sorting / stacking route A, the sheet is conveyed by the conveying roller pair 18 and the sheet discharging means 2
0, the sheet is discharged to the sheet discharge tray 6. Reference numeral SN3 denotes a paper discharge sensor, and reference numeral 22 denotes a paper discharge guide. In the staple route B, the sheet is transported by the transport roller pairs 24, 26, and 28, turned, sent to the staple unit 30, and subjected to the binding process. The bound sheets (bundle) are discharged to the discharge tray 6 by the sheet discharge means 20.

The sheet discharging means 20 includes a sheet discharging roller 32 driven by a driving source (not shown) and a driven roller 34.
And a support plate 36 for supporting the driven roller 34. The support plate 36 is rotatably supported on the free end side of the support plate 36, and is rotatably supported in the vertical direction with the rear end in the sheet discharge direction being pivotally supported. In the sort / stack mode, the driven roller 34 is in pressure contact with the discharge roller 32 under its own weight or under pressure by a spring or the like. The sheet is nipped and conveyed by a sheet discharge roller 32 and a driven roller 34 and discharged to the sheet discharge tray 6. After the trailing end of the sheet is discharged from the sheet discharging roller 32, the sheet is abutted against the trailing end fence 41 by the rotation of a sheet returning roll 39 provided on the lower surface side of the sheet discharging roller 32, and the trailing end is aligned. Be stacked. The return roller 39 is driven to rotate in the same direction as the discharge roller 32.

In the staple mode, the support plate 36 is displaced to the position shown by the two-dot chain line in order to prevent the rear end portion of the sheet bundle from bulging due to the pressure contact in the curved state. The paper roller 32 and the driven roller 34 are separated from each other, and in this state, a sheet bundle is released (described later). When the trailing end of the sheet bundle approaches the discharge roller 32, that is, at a stage where the possibility of swelling related to the discharge at the trailing end of the sheet bundle is eliminated, the support plate 36 is returned and the sheet bundle is discharged. And driven rollers 34 for discharging. The return timing of the support plate 36 is performed based on the detection information of the paper discharge sensor SN3.

Above the sheet discharging means 20, a sheet upper surface height detecting means 40 is provided. The seat upper surface detecting means 40 includes a detecting lever 42 and the detecting lever 4.
The sensor 42 has sensors 44 and 46 that are turned on when light is blocked by the second sector 42a.
and is rotatably provided in the vertical direction.
The sheets are successively discharged to the discharge tray 6, and as shown in FIG. 2, the upper surfaces of the stacked sheets are detected by the sensors 44 and 46 so that the height of the upper surface of the stacked sheets becomes substantially constant. The paper tray 6 is controlled to descend by a predetermined amount.
This control similar to the conventional control is called normal control.

As shown in FIG. 3, the paper discharge tray 6 is moved up and down by elevating means 60. The elevating means 60 includes an upper and lower lift belt 62 that lifts the sheet discharge tray 6, and the upper and lower lift belt 62 is connected to a gear train 64 and a timing belt 6.
6 and the like. The paper discharge tray 6 is raised or lowered by the forward or reverse rotation of the vertical motor 68, and the fullness of the paper on the paper discharge tray 6 is detected by the lower limit sensor 70. Vertical motor 6
8 is controlled by control means (not shown). When the discharge tray 6 is raised, as shown in FIG.
Is pushed up by the discharge tray 6, the upper limit switch 72 is turned off, and the up / down motor 68 stops rotating. As a result, breakage of the paper discharge tray 6 due to overrun is prevented. Although not shown, the sheet discharge tray 6 performs a shift operation in the sheet width direction orthogonal to the sheet discharge direction as needed to sort the sheets.

Next, the operation when the staple mode is selected will be described. As shown in FIG. 1, the sheet guided to the staple route B is a pair of transport rollers 24, 26, and 28.
, And are discharged and stacked on a staple tray (not shown) by the discharge roller pair 48. In this case, the alignment in the vertical direction (paper transport direction) is performed by the hitting roller 50 for each paper, and the alignment in the horizontal direction (paper width direction) is performed by the jogger fence 52. The stapler SP is driven by a staple signal from a control unit (not shown) between the end of the job, that is, between the last sheet of the sheet bundle and the leading sheet of the next sheet bundle, and the binding process is performed.

The sheet bundle subjected to the binding process is immediately conveyed by a discharge belt 56 having a discharge claw 54 in the sheet discharge direction (the direction of arrow b) and sent to the sheet discharge means 20.
The paper is discharged to the paper discharge tray 6. The discharged sheet bundle is abutted against the rear end fence 41 by its own weight and the rotation of the return roller 39, and the rear ends of the sheets are aligned and stacked. The sheet bundle is sequentially discharged to the paper discharge tray 6 by a predetermined number, and the lowering of the paper discharge tray 6 is controlled so that the upper surface of the paper is at a substantially constant position as in the sort / stack mode. The striking roller 50 is swung about a fulcrum 50a by a return solenoid (not shown), and acts intermittently on the sheet discharged to the staple tray to move the sheet to the rear end fence 58.
Hit it. At this time, since the brush roller 48a is provided in the discharge roller pair 48, the backflow of the rear end of the sheet is prevented. The beating roller 50 is rotating in the counterclockwise direction. Reference numeral SN4 denotes a home position detection sensor of the ejection claw 54.

Next, the control operation of this embodiment will be described with reference to FIG. Conventionally, the height of the sheet discharge tray 6 was adjusted mainly by the sensor 46 of the sheet upper surface height detecting means 40. However, in the present embodiment, when the face 75 is not curled, Although normal control is performed, if there is face curl, the sensor 46 is turned off when the load of the paper 75 increases and the sensor 44 is turned off for a certain period of time.
Is switched to the "control mode based on the sheet state" in which the sheet discharge tray 6 is lowered until is turned off.

According to this control, as shown in FIG. 5, the separation distance between the upper surface of the rear end of the sheet 75 in the discharge direction and the return roller 39 becomes larger than a predetermined amount (a value in the normal control). Even if there is a face curl, no entanglement by the paper discharge roller 32 or the return roller 39 occurs. Return roller 3
In the configuration having no 9, the lower end of the discharge roller 32 serves as a reference for the separation distance. In the case of the control corresponding to the face curl, the bundle of sheets 75 is removed and cannot be detected. Therefore, when a certain number of sheets are discharged onto the discharge tray 6, the discharge tray 6 is turned off until the sensor 44 is turned off. Cover by raising.

The process up to execution of the control mode based on the sheet state will be described with reference to the flowchart of FIG. First, the operator observes the discharge state of the paper 75 and determines whether or not the tray control needs to be changed (S1). If necessary, the operator turns on the control change key 78 on the operation panel 76 shown in FIG. 7 (S2).
When the control change key 78 is turned on, the control means (not shown) determines whether or not the control change number has been input (S).
3) If the number of control changes has been input, the number of sheets discharged onto the paper output tray 6 is compared with the input control change number (S4), and the control change number with the input number of sheets is determined. If it exceeds, the mode is switched to the control mode based on the sheet state (S5). The input of the number of control changes is made on the operation panel 7.
This is performed by the control change number input key 80 as the control change number setting means 6. When the control change number input key 80 is turned on, the number is set using a numeric keypad (not shown), and then the control change number input key 80 is turned on again, the control change number is input.

As shown in FIG. 7, the operation panel 76 is provided with a separation distance input key 82 as separation distance setting means. The separation distance input key 82 is input by the same operation as the control change number input key 80. Thus, when face curl occurs, the operator can change the descending distance of the sheet discharge tray 6 according to the degree of the curl so as to be suitable for the actual situation. In this case, the control unit controls the lowering of the sheet discharge tray 6 based on the input value, not based on the detection signal of the sheet upper surface height detection unit 40.

[0028] Regardless of the seat top height detecting means 40,
In the control for keeping the height of the upper surface of the paper constant by grasping the type (thickness) and the number of papers, the control mode based on the sheet state can be similarly performed. Further, the operation panel 76 may also serve as the operation panel of the image forming apparatus.

Next, a description will be given of an embodiment relating to a control operation in the case where a plurality of unbound sheet bundles are continuously discharged, with reference to FIGS. Since the configuration is almost the same as that of the above embodiment, the description is omitted. The difference is that the paper discharge sensor SN3 supports the driven roller 34 with the support plate 36.
It is a point provided in. As shown in the flowchart of FIG. 8, first, a control unit (not shown) determines whether or not the binding mode is set (S1), and in the case of the binding mode, determines whether or not to perform stapling (binding processing) (S2). If the binding process is not performed, it is determined whether the number of sheets stacked on the staple tray of the staple unit 30 is plural (S3). If the number is plural, before the sheet discharging unit 20 is driven, That is, before the discharge roller 32 and the return roller 39 are driven, the vertical motor 68 is driven to raise the discharge tray 6 (S4).

Next, whether or not the top sheet of the stack is pressed, that is, the sheet (group) 75 stacked on the discharge tray 6 is checked.
It is determined whether or not the rear end of the uppermost sheet 75a in the discharging direction has come into contact with the return roller 39 (sheet discharging means or the like) (S
5). In this embodiment, when the detection lever 42 rotates upward and the sensor 46 is turned on, the rear end of the uppermost sheet 75a in the discharge direction comes into contact with the return roller 39, and whether the sensor 46 is turned on. Judge by whether or not. For this determination, other means capable of detecting the uppermost surface of the paper 75 or means for raising the sheet 75 for a certain period of time may be employed.

When the sensor 46 is turned on, the vertical motor 68
Is stopped to stop the paper discharge tray 6 (S6). In this state, as shown in FIG. 9, the rear end of the paper 75 stacked on the paper discharge tray 6 is pressed by the return roller 39. In this state, the sheet discharging means 20 and the discharge belt 5
6 is driven to discharge a plurality of sheet bundles (sheet bundles) 84 stacked on the staple tray toward the discharge tray 6 (S7). In the state of FIG. 9, the return roller 39 is driven to rotate in the same direction as the paper discharge roller 32, so that in addition to being pressed on the uppermost paper 75 a, a force for returning to the rear end fence 41 is applied. Therefore, the sheet bundle 84 is not pushed forward in the discharging direction by the discharging operation. That is, the stacking state of the sheets 75 on the sheet discharge tray 6 is not disturbed by the discharge of the sheet bundle 84.

In this state, the sheet bundle 84 is discharged, and the control unit (not shown) determines whether the sheet bundle 84 has passed through the sheet discharging unit 20 (S8). In this embodiment, when the trailing end of the sheet bundle 84 is detected by the sheet discharge sensor SN3, it is determined that the sheet bundle 84 has passed through the sheet discharge unit 20.
When the trailing end of the sheet bundle 84 is detected by the sheet discharge sensor SN3,
The discharge tray 6 is lowered for a predetermined time (S9). As shown in FIG. 10, the lowering amount of the paper discharge tray 6 is
A gap is formed between the sheet bundle 9 and the rear end of the sheet 75, and the rear end of the discharged sheet bundle 84 can enter under the return roller 30 and be aligned with the rear end fence 41. Quantity. When it is confirmed by the timer that the predetermined time has elapsed, the discharge tray 6 is stopped (S1).
0).

Thereafter, it is determined whether or not the position of the discharge tray 6 is a normal position, that is, whether or not the position is a normal position (S).
11). Here, the normal position is, as shown in FIG.
The rear end of the sheet 75 (including the sheet bundle 84) stacked on the return roller 30 and the discharge tray 6 in a state where neither of the sensors 44 and 46 of the sheet upper surface detecting means 40 is turned on. Refers to the state where a gap exists between the part. If the discharge tray 6 is not at the normal position, a tray position setting operation is started to position the discharge tray 6 at the normal position (S12). This tray position setting is not limited to the sheet upper surface height detecting means 40, but may be performed by other means capable of detecting the uppermost surface of the sheet 75.

As shown in FIG. 11, before the operation of discharging the next plurality of unbound sheet bundles after discharging the plurality of unbound sheet bundles 84 in the discharge tray 6, as shown in FIG.
The control is performed so that the rear end of the uppermost surface of the paper 75 in the discharge direction does not contact the return roller 39, and the sorting operation such as shift is performed in this standby state. In this way, it is possible to prevent the stacked uppermost sheet from being rubbed by the contact with the return roller 39 to disturb the position.

The control operation for performing this sorting is shown in FIG.
This will be described with reference to the flowchart of FIG. First, the control unit (not shown) determines whether or not the binding mode is set (S1), and in the case of the binding mode, determines whether or not to perform stapling (binding processing) (S2). If the binding process is not performed, it is determined whether the number of sheets stacked on the staple tray of the staple unit 30 is plural (S3). If the number of sheets is plural, it is determined whether the sorting operation is necessary (S3). S4). Next, it is determined whether the position of the paper discharge tray 6 is at the normal position (normal position) (S5). If not, the positioning operation of the paper discharge tray 6 is started as in the above embodiment. (S6). When the position setting operation of the discharge tray 6 is completed (S7), the sorting operation for each sheet bundle by the shift operation of the discharge tray 6 is started (S8).

In the above-described embodiment, the unbound paper bundle 84 is placed on the paper 75 stacked on the paper discharge tray 6.
Is shown in the case of continuously discharging
This is also effective in preventing the sheet from shifting when the sheet bundle bound on the sheet 75 is discharged. Further, according to the control shown in FIG. 12, the same effect can be obtained when the bound sheet bundle is sorted. Further, in the above-described embodiment, the configuration in which the rear end portion of the sheet 75 is brought into contact with the return roller 39 to be pressed is shown. However, in the configuration without the return roller 39, the paper 75 may be brought into contact with the paper discharge roller 32 to be pressed.

[0037]

According to the first or fifth aspect of the present invention, when a predetermined amount of sheets is discharged, the distance between the upper surface of the rear end of the stacked sheets and the sheet discharging means becomes larger than a predetermined amount. Since the control for lowering the discharge tray is performed as described above, good stacking properties can be obtained even if the paper has face curl.

According to the second aspect of the present invention, since the control change number setting means capable of arbitrarily setting a certain amount of sheets is provided, the time for switching to the control mode based on the sheet state can be arbitrarily adjusted. it can.

According to the third aspect of the present invention, since the control mode based on the sheet state is executed based on the detection information of the sheet upper surface detecting means, highly accurate control according to the actual situation is performed. be able to.

According to the fourth aspect of the present invention, since the separation distance setting means for arbitrarily setting the separation distance is provided, an appropriate separation distance can be obtained according to the degree of face curl.

According to the sixth aspect of the invention, when discharging a plurality of unbound sheet bundles, the discharge tray is raised to discharge the upper surface of the sheets stacked on the discharge tray. Since the rear end is held down, it is possible to prevent the sheets on the output tray from shifting due to the discharge of the sheet bundle.
Good stacking properties can be obtained.

According to the seventh aspect of the present invention, the discharge tray is lowered before the sheet bundle passes through the sheet discharging means, so that the trailing edge of the discharged sheet bundle can be aligned well. .

According to the eighth aspect of the present invention, after discharging a plurality of unbound sheets in the sheet discharge tray, and before starting the discharging operation of the next plurality of unbound sheets, Waiting in a state where the rear end of the upper surface of the sheet in the discharging direction does not contact the sheet discharging means and the like, and performing a sorting operation such as shift operation in this waiting state, so that the uppermost sheet and the sheet discharging means and the like are controlled. Can be prevented from being disturbed due to rubbing, and sorting can be performed while maintaining good stackability.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a sheet post-processing apparatus as a sheet stacking apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a detecting operation of a seat upper surface detecting unit.

FIG. 3 is a perspective view showing an elevating means of a paper discharge tray.

FIG. 4 is a diagram illustrating a configuration for determining an upper limit of a discharge tray.

FIG. 5 is a main part front view in a control mode based on a sheet state when face curl occurs.

FIG. 6 is a flowchart of an operation up to a control mode based on a sheet state.

FIG. 7 is a schematic plan view of an operation panel.

FIG. 8 is a flowchart illustrating a control operation when a sheet bundle that is not bound is continuously discharged.

FIG. 9 is a main part front view of a state in which the discharge tray is raised and the rear end of the uppermost sheet is pressed.

FIG. 10 is a front view of an essential part in a state in which a discharge tray is lowered when an unbound sheet bundle passes through a sheet discharge unit.

FIG. 11 is a main part front view showing a state where the discharge tray is lowered and then positioned at a normal position.

FIG. 12 is a flowchart illustrating a control operation when sorting is performed when a sheet bundle that is not bound is continuously discharged.

FIG. 13 is a front view of a main part when a face curl occurs in the related art.

[Explanation of symbols]

6 Discharge Tray 20 Sheet Discharge Means 39 Return Roller 40 Sheet Top Height Detecting Means 60 Elevating Means 75 Sheet as Sheet 80 Control Change Number Input Key as Control Change Number Setting Means 82 Separation Distance Input Key as Separation Distance Setting Means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukitaka Nakazato 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Masahiro Tamura 1-3-6 Nakamagome, Ota-ku, Tokyo・ In Ricoh Co., Ltd. (72) Inventor Nobuyoshi Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H072 AA26 FB01 FB09 GA08 3F054 AA01 AC02 AC03 AC05 BA04 BD02 CA11 CA33 CA40 DA01 3F104 AA02

Claims (8)

[Claims] A sheet discharging means for discharging the sheet, a sheet discharging tray on which the sheets discharged from the sheet discharging means are stacked, and an elevating means for raising and lowering the sheet discharging tray; A control is performed to lower the discharge tray by a predetermined amount based on the stacked amount of the upper sheet,
In the sheet stacking device configured to keep the upper surface of the sheet at a substantially constant height, when a predetermined amount of the sheet is discharged to the discharge tray, the upper surface of the rear end of the stacked sheet in the discharge direction, the sheet discharge unit, A sheet stacking device having a control mode based on a sheet state, wherein the discharge tray is lowered so that the separation distance of the sheet is larger than the predetermined amount. 2. The sheet stacking apparatus according to claim 1, further comprising a control change number setting means for arbitrarily setting a certain amount of the sheets. 3. The sheet stacking device according to claim 1, further comprising sheet upper surface height detecting means for detecting the height of the upper surface of the sheets stacked on the sheet discharge tray. A sheet stacking device wherein a control mode based on the sheet state is executed based on detection information. 4. The sheet stacking apparatus according to claim 1, further comprising a separation distance setting means for arbitrarily setting the separation distance. 5. A sheet stacking apparatus according to claim 1, further comprising a return roller for aligning the trailing end of the discharged sheet, wherein said separation distance is based on a lower end of said return roller. A sheet stacking device characterized by being set. 6. The sheet discharge tray comprising sheet discharge means for discharging sheets, a sheet discharge tray on which sheets discharged from the sheet discharge means are stacked, and elevating means for raising and lowering the sheet discharge tray. A control is performed to lower the discharge tray by a predetermined amount based on the stacked amount of the upper sheet,
In the sheet stacking device in which the upper surface of the sheet is maintained at a substantially constant height, when continuously discharging a plurality of sheet bundles that are not bound to the discharge tray, the sheet discharging unit starts a discharging operation. A sheet stacking device for controlling the sheet stacker to raise the sheet discharge tray before the sheet discharge tray and to control the rear end portion of the upper surface of the sheets stacked on the sheet discharge tray to come into contact with the sheet discharge means or the like. . 7. A sheet stacking apparatus according to claim 6, wherein said sheet discharge tray is lowered before said sheet bundle passes through said sheet discharge means. 8. The sheet stacking device according to claim 6, wherein after discharging a plurality of sheet bundles that are not bound to the discharge tray, a discharging operation of the next plurality of unbound sheet bundles is performed. Before entering, the sheet waits in a state where the rear end of the upper surface of the sheet in the discharge direction does not contact the sheet discharging means or the like, and the sheet is controlled so that sorting operation such as shift is performed in this wait state. Loading device.