JPH11165938A - Paper loading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid failures such as a sliding contact, a rolling-in and an increase in load which are caused by a contact of a revolving a paper ejecting roller and paper by having a control means lowering a paper ejecting tray from a reference paper receiving location before revolution of the paper ejecting roller is started. SOLUTION: A paper ejecting tray 12 is elevated or lowered by normal revolution or reversing of upper and lower motors via upper and lower lift belts. A paper space lever 13 and paper space sensors 32, 33 (the paper space sensor 32 at the time of a normal mode and the paper space sensor 33 at the time of a staple mode) detect the location of the paper ejecting tray 12. At the time of ejecting paper, a control is performed by a microcomputer so as to lower the paper ejecting tray 12 by at least amount that the top surface of loaded paper and the paper ejecting roller 3 are separated from a reference paper receiving location before the paper ejecting roller 3 starts to revolve. Thus, failures caused by revolution of the paper ejecting roller 3 can be eliminated in a state that the paper ejecting roller 3 and paper on the paper ejecting tray 12 come into contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet stacking apparatus which can be provided in a sheet discharge section of an image forming apparatus or the like.

[0002]

2. Description of the Related Art A paper discharge tray is provided which can be moved up and down, on which paper discharged from an image forming apparatus or the like is stacked, and a paper discharge roller which is disposed above the paper discharge tray and feeds the paper to the paper discharge tray. There is a sheet stacking device that receives a sheet from the discharge roller at a reference sheet receiving position in which the discharge tray is spaced downward by a predetermined amount from the discharge roller.

[0003] The above-mentioned reference paper receiving position is such that, even for normal paper that is not curled, or paper that has been stapled, a staple needle is struck at a part other than the part facing the discharge roller. It is set assuming things,
The detection position of the uppermost surface of the paper by the sensor for setting and controlling the reference paper receiving position of the paper discharge tray is shifted from the position facing the paper discharge roller.

[0004]

For this reason, the stapled portion of the stapled paper is in a paper discharge state in which the staple portion corresponds to the paper discharge roller, or the curled portion of the staple paper has a paper discharge portion. If the paper is in a state of discharge corresponding to the roller portion and such papers are stacked on the paper discharge tray, at first, the distance between the top surface of the paper and the paper discharge roller Maintains the desired interval for paper ejection, but as the paper stack increases,
The swelling due to the curl of each sheet is added, or the swelling of the stipple portion is added to the paper subjected to stapling, and the expected interval between the top surface of the swelling portion and the discharge roller is maintained. It becomes impossible, and finally the curled paper and the paper discharge roller or the part of the paper stipple and the paper discharge roller are in sliding contact with each other, and the paper discharge roller entrains the paper and deteriorates the stacking property,
In the extreme case, the load on the paper discharge roller increases, and the paper is damaged. In extreme cases, the paper discharge roller is scraped, or the paper discharge roller does not rotate due to excessive load.

An object of the present invention is to provide a sheet stacking apparatus capable of avoiding the above-mentioned problems caused by contact between a rotating sheet discharging roller and a sheet, which is generated for a sheet discharged in such a special mode. The purpose is to provide.

[0006]

The present invention has the following configuration to achieve the above object.

(1) A vertically movable paper discharge tray on which discharged paper is stacked, and disposed above the paper discharge tray,
A paper discharge roller for feeding paper to the paper discharge tray,
In a sheet stacking device that receives a sheet from the discharge roller at a reference sheet receiving position in which the discharge tray is separated from the discharge roller by a predetermined amount and downward, before the rotation of the discharge roller is started, There is provided control means for lowering the discharge tray from the reference sheet receiving position (claim 1).

(2) In the paper stacking apparatus according to (1),
The control means performs a first down mode in which the discharge tray is held at a first sheet receiving position lower than the reference sheet receiving position until the rotation of the discharge roller is stopped. (Claim 2).

(3) In the sheet stacking apparatus according to (1), the control means may control the discharging of the sheet after the rotation of the sheet discharging roller is started and before the sheet is fed from the sheet discharging roller. A second down mode for raising the paper tray toward the reference paper receiving position is performed (claim 3).

(4) In the paper stacking apparatus according to (3), the control means may control the discharge of the paper again after the discharge tray is raised and before the paper is completely fed from the discharge roller. The paper tray is lowered (claim 4).

(5) In the sheet stacking apparatus according to (1), (2), (3), or (4), the amount of lowering of the discharge tray is at least the sheet stacked on the discharge tray. The distance between the uppermost surface and the discharge roller is determined.

(6) In the sheet stacking apparatus according to (1), the control means may control the first position of the discharge tray to be lower than the reference sheet receiving position until the rotation of the discharge tray is stopped. A first down mode in which the paper is held at the paper receiving position, and after the rotation of the paper discharge roller is started and before the paper is sent out from the paper discharge roller,
The setting can be made so as to be performed in one of the second down modes for returning the sheet discharge tray to the reference sheet receiving position (claim 6).

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Overall Configuration of Sheet Post-Processing Apparatus The overall configuration and operation of a sheet post-processing apparatus including a sheet stacking apparatus suitable for carrying out the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 600 denotes a finisher as an example of a sheet post-processing apparatus for sorting, collating and stapling recording sheets discharged from a copying machine or the like (not shown). In the finisher 600, an entrance sensor 36, an entrance roller 1, and a branch claw 8 are provided at the entrance of a paper discharge / conveyance path from a copying machine or the like in the order in which the paper travels. By the switching of the position by the rotation of the branch claw 8, the sheet sent to the sheet discharge tray 12 side,
The sheet sent to the staple device 11 is separated.

In the transport path leading to the paper output tray 12, a pair of upper transport rollers 2a and 2b, a paper output sensor 38 for detecting the leading and trailing edges of the paper, a pair of paper output rollers 3, a shift roller 7, a paper surface lever 13, paper surface sensors 32, 33 (FIG. 7)
(A) and FIG. 7 (b)).

In the transport path toward the staple device 11, lower transport rollers 4a and 4b, a paper discharge sensor 37, a paper feed roller (brush roller) 6, and the like are arranged. The lower transport roller 4a and the lower transport roller 4b, which are connected by a belt, are driven by a transport motor 54, which will be described later, and the paper discharge tray 12 is appropriately moved up and down (in FIG. Up and down), left and right (Fig. 1
(In the direction that penetrates the paper).

The staple device 11 is provided below the staple tray 62 as shown in FIG. As shown in FIGS. 1 and 2, the staple tray 62 is stapled (stitched) at positions behind the jogger fences 9a and 9b, the return roller 5, and the jogger fences 9a and 9b for aligning sheets. 2.) A discharge belt 10 for discharging a sheet bundle is provided. As shown in FIG. 2, the jogger fences 9a and 9b are driven by a jogger motor 26 via a jogger belt 49, and the return roller 5 is configured to swing by a return solenoid 30.

Although omitted in FIG. 2, a rear end fence 19 for receiving the lower side of the sheet is provided below the jogger fences 9a and 9b, as shown in FIGS.

As shown in FIG. 4, the staple device 11 is attached to the staple belt 50, and moves in the lateral direction (the direction penetrating the plane of FIG. 1) in accordance with the movement of the staple belt 50 by the rotation of the stapler moving motor 27. Go to
1 and 2, a paper discharge sensor 37 detects the rear end of the paper. The return solenoid 30 operates the return roller 5 upon receiving an ON command based on the trailing end detection signal of the sheet discharge sensor 37. The return roller 5 is arranged at a position where it can strike the rear end of the sheet, and aligns the sheet.

Referring to FIG. 6, a circuit configuration using a microcomputer as control means built in the sheet post-processing apparatus will be described. Signals from switches and sensors in the sheet post-processing apparatus are input to the CPU 70 via the I / O interface 60. The CPU 70 operates the vertical motor 23, the shift motor 52, the branch solenoid 5 according to the input signal.
3. Drive the return solenoid 30, the transport motor 54, the paper discharge motor 55, the staple motor 56, the discharge motor 57, the stapler moving motor 27, and the jogger motor 26.

The pulse signal of the transport motor 54 is sent to the CPU 70
The return solenoid 30 is controlled in accordance with the count. The alignment control unit for aligning the sheets includes the CPU 70 and various operation programs for operating the CPU 70.

(2) Operation of Paper Post-Processing Apparatus [Normal Mode] In the above configuration, first, an operation when a normal mode in which staple processing is not performed is selected will be described. In FIG. 1, a copied sheet is received by an entrance roller 1 and travels along a path directly toward a sheet discharge tray 12 by a path control of a branch claw 8, and is sent by upper conveying rollers 2 a and 2 b to form a pair of sheet discharge rollers 3. Is discharged by

As shown in FIGS. 1, 7 (a), 8 (a) and 8 (b), on the stacking surface of the paper discharge tray 12, a shift roller 7 made of a sponge-like material can swing. It is in contact with its own weight. The paper sent out onto the paper output tray 12 slides down along the inclined surface, and when the lower side is sandwiched by the shift roller 7,
Rear end fence 29 (see FIG. 1) serving as a sheet receiving means that is fed downward by the shift roller 7 and heads downward.
And alignment in the vertical direction (paper feed direction) is performed. Here, the shifting roller 7 is rotating to feed the sheet, but when the sheet ejection sensor 38 detects the trailing edge of the sheet, the rotation speed is reduced to improve the stacking property.

In this way, the copied paper is sequentially discharged onto the discharge tray 12 one after another. Then, the top surface of the stacked papers rises. As shown in FIG. 7A, one end of a paper lever 13 swingably supported by a shaft 13a is provided on the uppermost surface of the stacked paper so as to come into contact with its own weight. The other end is detected by a paper surface sensor 33 composed of a photo interrupter. The paper surface sensor 33 is for controlling the vertical position of the paper discharge tray in the normal mode in which staple processing is not performed, and the paper surface sensor 32 is for performing similar control in the staple mode.

In this case, since the mode is the normal mode, the loading surface of the paper rises every time the paper is discharged one by one, and the vertical motor 23 is driven each time the free end of the paper lever 13 is released from the paper surface sensor 33. Then, control is performed to lower the paper discharge tray 12 until the paper surface sensor 33 is turned on. Thereby, the condition of the landing position of the sheet on the sheet discharge tray 12 is as follows:
As shown in FIG. 10, the distance between the discharge roller 3 and the discharge tray 12 is maintained at a constant value of L. Note that FIG.
FIG. 1 illustrates a case where there is no sheet on the sheet discharge tray 12, but even when sheets are stacked, the distance L from the top surface of the sheet to the sheet discharge roller 3 is constant. In this way, the discharge tray 1 that is spaced a predetermined distance L from the discharge roller 3
The position No. 2 is referred to as a reference sheet receiving position, and is a position set as an appropriate position for receiving a sheet in a normal state other than a sheet fed in a special mode such as curling.

The paper discharge conditions are different between the case where the paper is discharged one by one in the normal mode and the case where the paper stapled in the staple mode is discharged. The position is different. This is apparent from the fact that the positions of the paper surface sensors 32 and 33 are different.

In the sort and stack mode, the discharge tray 12 is shifted by a predetermined amount in the horizontal direction by the shift motor 52 by a partition signal output from the control panel of the copying machine, and the stacking position is changed until the job is completed. Perform sorting. At the end of the job, the discharge tray 12 is lowered by about 30 mm in preparation for taking out the sheet.
[Stiple Mode] Next, the operation when the stapling mode is selected and the stapling process is performed will be described. When the stipple mote is selected, the jog fences 9a and 9b move from the home position and stand by at a position about 7 mm apart on one side of the sheet width as shown in FIG. In FIG. 1, when the paper is driven by the transport motor 54, the paper is transported by the lower transport rollers 4a and 4b, and when the trailing end of the paper passes the paper ejection sensor 37, the jogger fences 9a and 9b are moved inward by 5 mm from the standby position. Jogging (movement in the direction of the black arrow in FIG. 2) is performed.

The paper discharge sensor 37 detects the passage of the trailing edge of the sheet when the trailing edge of the sheet has passed, and outputs the signal to the CPU 7.
When the signal is received, the CPU 70 counts the number of oscillation pulses from the conveyance motor 54 from the time when this signal is received, and turns on the return solenoid 30 after a predetermined pulse oscillation.

The return roller 5 swings by turning the return solenoid 30 on and off. When the return solenoid 5 is on, the return roller 5 hits the sheet to return downward, and hits the rear end fence 19 to align the sheet. At this time, the paper stored in the staple tray 62 is moved to the entrance sensor 36 (or the paper ejection sensor 3).
Every time the signal passes through 7), the signal is input to the CPU 70, and the number of sheets is counted.

After a predetermined time has elapsed since the return solenoid 30 was turned off, the jogger fences 9a and 9b were moved inward by 2 mm by the jogger motor 26 and stopped temporarily.
Horizontal alignment ends. Jogger fence 9 is then 7mm
Return and wait for the next sheet. This operation is performed up to the last page. On the last page, jogging of 7 mm is performed again to hold both ends of the sheet bundle and prepare for the stapling operation. Thereafter, the staple device 11 is operated after a predetermined time, and the binding process is performed. At this time, if a plurality of bindings are designated, after the binding processing at one location is completed, the staple moving motor 27 is driven, the staple device 11 is moved to an appropriate position along the rear end of the sheet, and the second location is selected. A binding process is performed.

When the binding process is completed, the discharge belt 57 is driven by driving the discharge motor 57 shown in FIG. At this time, the paper discharge motor 55 is also driven, and starts rotating to receive the sheet bundle lifted by the discharge claw 10a. At this time, the operation of the jogger fence 9 is controlled so as to differ depending on the size and the number of sheets to be bound.

For example, when the number of sheets to be bound is smaller than the set number or smaller than the set size, the ejection claws 1 are held down while holding the sheet bundle by the jogger fences 9a and 9b.
0a, the rear end of the sheet bundle is hooked and conveyed. And
After counting the predetermined number of pulses from the discharge belt home sensor 39, the jogger fences 9a and 9b are retracted by 2 mm to release the constraint on the sheet by the jogger fences 9a and 9b. The predetermined pulse is set during a period from when the ejection claw 10a collides with the rear end of the sheet bundle and passes through the tips of the jogger fences 9a and 9b.

When the number of sheets to be stapled is larger than the set number or larger than the set size, the jogger fences 9a and 9b are retracted by 2 mm in advance to perform ejection.
In each case, the bundle of sheets is jogged by the jogger fences 9a and 9b.
After passing through, jogger fences 9a and 9b are 5m further
m, return to the standby position, and prepare for the next sheet. Note that the binding force can be adjusted by the distance between the jogger fences 9a and 9b with respect to the sheet. The above series of operations is repeated until the last job.

As shown in FIG. 7A, the paper discharge tray 12 is suspended by a vertical lift belt 48. The vertical lift belt 48 is driven by the vertical motor 23 via a gear train and a timing belt, and is raised or lowered by the forward or reverse rotation of the vertical motor 23.

The home position (H
P) Reference paper receiving position, and as described above, the paper surface lever 13 and the paper surface sensors 32, 3
3 (the paper surface sensor 33 in the normal mode, and the paper surface sensor 32 in the stipple mode).

In any of the modes, the paper from the paper discharge roller 3 is discharged onto the paper discharge tray 12 at the reference paper receiving position in each mode, and the paper discharge tray 12 is lowered every time the paper is stacked. Finally, the lower limit sensor 34 detects the lower limit position. In addition, when the discharge tray 12 reaches a predetermined rising limit position when the discharge tray 12 is raised,
As shown in FIG. 8B, the shift roller 7 is also pushed up by the upper surface of the sheet discharge tray 12. The shift roller 7 is a fulcrum shaft 7
The paper tray 12 is swingable about a.
Is reached at a predetermined ascending limit position, the swinging end pushes the upper limit switch 31 of the discharge tray to turn it on.

FIG. 8A shows a state in which the upper limit switch 31 is off, and FIG. 8B shows a state in which the upper limit switch 31 is on. As shown in FIG. 8B, when the upper limit switch 31 is turned off, the driving of the vertical motor 23 is stopped to prevent the paper discharge tray 12 from being damaged due to overrun.

The rear end fence 19 shown in FIG. 4 is composed of four parts. The fences 19a and 19b are fixed types and are fixed to the paper discharge tray 12. Fence 19
The c and 19d are movable types and are provided in the staple device 11 and move together with the staple device 11.

(3) Description Corresponding to Claims In the following example, the sheet stacking device is a sheet discharging tray 12 and a sheet discharging roller 3 of the sheet post-processing device described above.
And a paper discharge sensor 3 provided immediately before the paper discharge roller 3.
8. Means (equivalent to the discharge belt home sensor 37 or the entrance sensor 36) which are provided at a position upstream of the paper discharge sensor 38 and which can confirm any change for the advance of the dischargeable paper to the paper discharge tray and these And a control means (hereinafter simply referred to as control means) mainly including a CPU 70 shown in FIG. 6 for controlling these in a predetermined procedure. A sheet stacking apparatus having such a configuration can be widely used as an apparatus for stacking sheets, attached to a sheet discharging apparatus such as a facsimile, a copying machine, or the like.

As described above, since the discharge roller 3 rotates while the discharge roller 3 and the paper stacked on the discharge tray 12 are in contact with each other, a problem has occurred. As described below, before the rotation of the paper discharge roller 3 is started by the control means when the paper is discharged, the paper discharge tray 12 is stacked at least from the reference paper receiving position on the paper discharge tray 12. The discharge roller 3 is controlled so as to be lowered by an amount that separates the uppermost surface of the paper sheet from the paper discharge roller 3 (claims 1 and 5). With such control, the above-described problem in the related art is immediately solved.

Then, the control means further controls the discharge tray 12 to a first sheet receiving position lower than the reference sheet receiving position until the rotation of the discharge roller 3 is stopped, that is, as shown in FIG. Is a position indicated by a two-dot chain line, the distance from the paper discharge roller 3 is maintained at a position of L1, and a first control is performed such that paper is received on the paper discharge tray 12 at the first paper receiving position. A down mode can be performed (claim 2). When the paper is completely discharged at the first paper receiving position, in order to avoid interference with the paper, the rotation of the paper discharge roller is stopped, and then the paper discharge tray 12 is raised to the reference paper receiving position. And the same control is repeated.

Therefore, in the first down mode, the rotation of the sheet while the discharge roller 3 is in contact with the sheet is avoided, but the first sheet receiving position (the position of the interval L1 shown in FIG. 10). Is lower than the reference paper receiving position (the position of the interval L shown in FIG. 10) as viewed from the paper discharge roller 3, so that the falling distance of the paper becomes large,
In particular, in the case of a sheet having a weak paper stiffness, the leading end on the downstream side of the sheet being sent out from the sheet ejection roller 3 is bent into a bent shape, that is, a so-called leading end is rounded, and the alignment is disturbed. This may cause inconvenience such as damaging the paper.

In order to cope with such a case, assuming the above-described control, the sheet is temporarily lowered after the rotation of the sheet discharging roller 3 is started and before the sheet is fed from the sheet discharging roller 3. Control is performed so as to perform the second down mode in which the discharge tray 12 is raised toward the reference sheet receiving position (claim 3). The paper output tray 12 is raised before the paper is sent out from the paper output row 3, and the paper edge is received on the surface of the paper output tray 12 before the paper edge is rounded, thereby preventing the paper edge from being rounded. can do.

Therefore, until the trailing edge of the paper is completely landed on the paper discharge tray 12 as well as the leading edge of the paper, the paper
May be continued, but depending on the control timing and the setting of the moving speed, the placement tray 12 may reach the reference sheet receiving position before the rear end of the sheet completely lands. If this is the case, the uppermost curled surface portion of the paper already on the paper discharge tray 12 or the portion where the staples are present comes into contact with the paper discharge roller 3, so that the rear end of the paper in the above paper discharge process is You will not be able to send it out completely.

In order to avoid such a situation, on the premise of the above-described control, after the discharge tray 12 is raised and before the feeding of the paper from the discharge roller 3 is completed, that is,
Before the trailing edge of the paper lands on the paper discharge tray 12, the paper discharge tray 12 is lowered again (claim 4). In this case, the paper discharge tray 12 is lowered to the first paper receiving position and stopped. Therefore, the sheet in the paper discharging process may be completely fed to the paper discharging tray 12 at the trailing end in the process of lowering the paper discharging tray 12, or may be waiting at the first paper receiving position. It may be sent out onto the output tray 12. In any case, the paper is sent onto the paper discharge tray 12 without any trouble.

After the paper is completely discharged, in order to avoid interference with the paper, the rotation of the paper discharge roller is stopped, and then the paper discharge tray 12 is raised to the reference paper receiving position. And the same control is repeated.

The control according to the above (1) to (5) is described below with reference to FIG.
This can be achieved by control means following the procedure described in (1).
In this case, in the case where the sheet stacking apparatus is configured such that the first down mode and the second down mode can be selected, the flow shown in FIG. 9 is used.

In the case of the above-described paper stacking apparatus capable of performing the first down mode, in the flow of FIG.
It is possible to follow a flow in which the procedure from step S4 to step S8 is omitted.

In the case where the above-described or the second down mode according to the present invention is applied to the sheet stacking apparatus, the flow of FIG. 9 can be made to follow the flow in which the procedure of step S4 is omitted.

In these cases, the first down mode and the second down mode
Selection of each mode, such as the down mode, may be performed by switching a mode selection key provided on the control panel. Alternatively, when the apparatus is combined with a device capable of the staple mode, the staple mode is set. The setting may be made in conjunction with the setting, or alternatively, the setting may be made in conjunction with the detection information from the means capable of identifying the easily curlable paper regardless of the normal mode or the staple mode. When any of these down modes is designated, the control means recognizes this and determines "yes" in step S1 or step S4 shown in FIG.

Here, the reference paper receiving position differs between the normal mode and the staple mode. However, in both the above description and the following description, in order to avoid complication, in any case, as shown in FIG. The paper discharge tray 1 having a distance L between the paper tray 12 (the upper surface of the paper when there is no paper on the tray, and the uppermost surface of the paper if there is paper) and the paper discharge roller 3
The position 2 will be described as a reference sheet receiving position.

A specific example of the down mode of the sheet post-processing apparatus including the sheet stacking apparatus having the configuration shown in FIGS. 1 to 8 will be described below with reference to FIG. 9 focusing on the staple mode.

In FIG. 9, this flow is a change for sending out a sheet ready to be discharged toward a sheet stacking sheet, that is, the discharge belt home sensor 37 causes the discharge belt 10 to be driven by the discharge motor 57. In step S, the start detection is used as a trigger, or in the case of the normal mode, the detection of paper by the entrance sensor 36 is used as a trigger.
At 1, it is determined whether the mode is the down mode. If the mode is the down mode, the process proceeds to step S2; otherwise, the process returns. When the above trigger,
The timer starts counting from the time point T ₀ in FIG. 11 (time point 0), and at the same time, the vertical motor 23 is activated, and the discharge tray 12 descends from the reference sheet receiving position (the position indicated by the solid line in FIG. 10). Start.

From time T ₀ , at time T ₁ when a predetermined time (t ₁ ), which has been set in advance as a time for the discharge roller 3 to separate from the sheet on the discharge tray 12, elapses.
Starts rotating (step 3). The predetermined time (t ₁ ) is set as the time from when the ejection claw 10a is activated from the home position, the sheet subjected to the stapling process is hooked at the portion of the rear end fence 19, and starts rising together with the sheet. Can be.

At the same time as step 3, it is determined in step 4 whether or not the second down mode is set. If it is not the second down mode, it jumps to step S6 to execute the first down mode, and if it is the second down mode, it goes to step S5. Therefore, the case of the first down mode and the case of the second down mode will be separately described below.

(A) In the case of the first down mode The sheet discharge tray 1 which has started descending in step S2
At time 2, a predetermined time (t ₂ ) which has been set in advance as the time required for the discharge tray 12 to descend to the first sheet receiving position (the position indicated by the two-dot chain line in FIG. 10) has elapsed from the time T ₀ . stop lowered at time T _2, is held in the first sheet receiving position (step S9). By this time, the sheet is in progress, and is set in advance by a timer as a time required for the sheet to completely land on the discharge tray 12 after the sheet discharge sensor 38 detects the trailing end of the sheet. When the predetermined time has elapsed, the rotation of the discharge roller 3 is stopped (step S10).

If the rotation of the paper discharge roller 3 stops, there is no obstacle even if the upper surface of the paper comes in contact with the stopped arrangement roller, so that the paper discharge tray 12 can be raised immediately. Therefore, the discharge tray 12 is raised in step S11. The discharge tray 12 is raised to a reference sheet receiving position. Therefore, in step S12, the discharge tray 12 is stopped in step S13 on condition that the paper surface sensor 32 is detected (ON) via the paper surface lever 13. As a result, the discharge tray 12 returns to the reference sheet receiving position indicated by the solid line in FIG. 10, and waits for the next sheet to arrive.
Similar control is performed.

(B) Second Down Mode In the state where the paper discharge roller 3 is rotating and the paper discharge tray 12 is moving down, in step S5, the paper discharge sensor 3
Waiting for the detection of the leading edge of the sheet by S8 (sensor ON), and when the detection is detected, the discharge tray 12 turns from descending to ascending (step S6). This is because the leading end of the sheet is received by the sheet discharge tray 12 at a high position in order to prevent the leading end of the sheet from being rounded, and the optimum position can be a reference sheet receiving position. Therefore, step S5
Between step and step S6, it is effective to provide a predetermined time interval at which the sheet can be raised to a position where the sheet can be received without rounding the leading end. This time is actually determined,
Set by a timer.

The fact that the leading edge of the paper has landed on the paper discharge tray 12 in this manner is determined by the paper discharge sensor 3 in step S7.
8 determines the trailing edge of the sheet by detecting (turning off the sensor). However, for this purpose, it is necessary that the position of the paper discharge sensor 38 satisfies predetermined conditions in relation to the paper discharge rollers 3 and the tray 12 and in relation to the size of paper. In this example, since the paper ejection sensor 38 is located near the paper ejection roller, the trailing end of the paper is
8, the leading edge of the sheet is sufficiently on the sheet discharge tray 12.

When the trailing edge of the sheet is detected in step S7, the time is managed by a timer with reference to this time in step S8. The discharge tray 12 that has started to ascend is turned down. This descent
The sheet sent out onto the tray 12 descends along the inclined surface of the tray 12 without interfering with the sheet discharge rollers 3, and is provided with a space enough for the rear end of the sheet to reliably hit the rear end fence 29. The trailing edge of the sheet is fed out by the discharge roller 3 at least after the space is created. This descent is performed in step S
9 to stop. After step S9, (a)
The description is omitted here.

[0060]

According to the first, second and fifth aspects of the present invention,
The curled paper and the paper discharge roller or the part of the paper stipple and the paper discharge roller are in sliding contact with each other due to the contact between the rotating paper discharge roller and the paper. Problems, such as poor performance, increased load on the discharge roller, and damage to the paper. In extreme cases, the discharge roller may be scraped, or the discharge roller may not rotate due to excessive load. Can be avoided. According to the third aspect of the invention, it is possible to prevent the leading end of the sheet from being rounded. According to the invention described in claim 4,
The paper can be reliably aligned on the paper output tray, and the interference between the paper and the paper output roller is avoided, so that the paper and the paper output roller are prevented from being worn, and the load on the paper output roller is also reduced. It is reduced. According to the invention of claim 6, it is possible to select a mode as needed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a sheet post-processing apparatus.

FIG. 2 is a perspective view illustrating a main part of the sheet post-processing apparatus.

FIG. 3 is an explanatory diagram of a portion near a jogger fence of a staple tray.

FIG. 4 is a perspective view of a staple device portion.

FIG. 5 is an explanatory diagram of a transport system after a stapling process.

FIG. 6 is an explanatory diagram of control means.

FIG. 7A is a perspective view illustrating a main part of the sheet stacking device, and FIG. 7B is a perspective view of a paper surface sensor.

FIGS. 8A and 8B are diagrams illustrating the operation of the shifting roller.

FIG. 9 is a flowchart illustrating a control procedure of a control unit according to the present invention.

FIG. 10 is a diagram illustrating the position of a paper discharge tray.

FIG. 11 is a time chart for explaining the operation of the paper sanction device.

[Explanation of symbols]

 3 Discharge Roller 12 Discharge Tray 70 CPU as Control Means

Continued on the front page (72) Inventor Masahiro Tamura 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Company (72) Inventor Kenji Yamada 1-3-6 Nakamagome, Ota-ku, Tokyo, Co., Ltd. Inside Ricoh (72) Inventor Yoshihiko Nakayama 2-2-13 Nishiki, Naka-ku, Nagoya City, Aichi Prefecture / Ricoh Elemex Corporation

Claims (6)

[Claims] A discharge tray that can be moved up and down to stack discharged paper; and a discharge roller that is disposed above the discharge tray and feeds the paper to the discharge tray. A sheet stacking device that receives a sheet from the sheet discharge roller at a reference sheet receiving position that is separated downward by a predetermined amount from the sheet discharge roller, wherein the sheet discharge tray is rotated before the rotation of the sheet discharge roller is started. A sheet stacking device having a control unit for lowering the sheet from the reference sheet receiving position. 2. The paper stacking device according to claim 1, wherein said control means controls the rotation of said discharge roller until said rotation of said discharge roller is stopped.
A sheet stacking apparatus for performing a first down mode in which the sheet discharge tray is held at a first sheet receiving position lower than the reference sheet receiving position. 3. The sheet stacking device according to claim 1, wherein said control means is configured to start the rotation of said sheet discharge roller and before the sheet is sent out from said sheet discharge roller.
A sheet stacking apparatus, wherein a second down mode is performed in which the discharge tray is raised toward the reference sheet receiving position. 4. The sheet stacking apparatus according to claim 3, wherein said control means controls the discharge of the sheet again after the discharge tray is raised and before the sheet is completely fed from the discharge roller. A sheet stacking device characterized by lowering a tray. 5. The paper stacking device according to claim 1, wherein the amount of lowering of the paper discharge tray is at least the top surface of the paper stacked on the paper discharge tray and the paper discharge tray. A sheet stacking device wherein the roller is separated from the roller. 6. The sheet stacking apparatus according to claim 1, wherein said control means controls said first tray to be lower than said reference sheet receiving position until said discharge tray stops rotating. A first down mode for holding the sheet at the sheet receiving position, and after the rotation of the sheet ejection roller is started and before the sheet is fed from the sheet ejection roller, the sheet ejection tray is set to the reference position. Second to return to paper receiving position
Characterized in that it can be set to be performed in one of the down modes.