JP5821491B2 - Sheet stacking device and post-processing device - Google Patents

Description

  The present invention relates to a sheet stacking apparatus that sequentially introduces and stacks a plurality of sheets onto a tray, and a post-processing apparatus including the sheet stacking apparatus.

In recent years, in image forming apparatuses such as copying machines, there are many cases in which a post-processing apparatus that performs a staple process or the like is attached to a recording sheet output from the image forming apparatus.
Such a post-processing apparatus has a sheet stacking apparatus that sequentially introduces and stacks the recording sheets output from the image forming apparatus to the tray, and when the number of recording sheets designated by the user is stacked on the tray, Staple processing is executed by the staple unit.

  Although the recording sheets are introduced into the tray one by one by the sheet stacking device, the recording sheets already stacked in the tray are curled, and the peripheral portion of the recording sheet introduction position is from the sheet mounting surface of the tray. If it floats, it closes the recording sheet inlet and collides with the newly introduced recording sheet, causing the recording sheet to be bent or a new recording sheet to enter under the floating recording sheet. There is a risk of inconvenience such as replacement.

  In order to prevent such inconvenience, for example, in Patent Document 1, the portion of the recording sheet that has been introduced into the tray and placed thereon is curled and directed to a flat placement surface by a roll-shaped pressing member. The roll-shaped pressing member is separated from the recording sheet at a predetermined timing, and the next recording sheet is stacked.

JP 2004-83261 A

However, depending on the technique disclosed in Patent Document 1, the curling of the recording sheet may not be sufficiently corrected, and the curled shape may be restored with the separation of the pressing member, and the recording sheet introduction port may be blocked.
The present invention has been made in view of the above circumstances, and a sheet stacking apparatus and a sheet stacking apparatus that perform a smooth stacking operation by more reliably preventing the recording sheet mounted on the tray from being lifted. An object of the present invention is to provide a post-processing apparatus provided.

In order to achieve the above object, a sheet stacking apparatus according to the present invention is a sheet stacking apparatus that sequentially introduces and stacks a plurality of sheets onto a tray, on which the introduced sheets are mounted. A tray having a surface and having a receding portion formed by retreating a region corresponding to the rear end portion of the sheet in the placement state on the placement surface, and a first position sandwiching the introduction position of the sheet, A pressing member that is movably provided at the second position and that presses the rear end portion toward the retracted portion in accordance with the movement to the first position, and the pressing member is at the second position. A rear end regulating member that is interposed between the pressing member and the retracted portion of the tray and regulates the rear end of the sheets stacked on the tray so as not to float up and block the sheet introduction position; Driving hand for selectively moving the member to the first and second positions When, wherein the trailing edge regulating member is retractable toward the rear end side of the tray, said pressing member, when moving from the second position to the first position, the rear end Engage with the engaging portion of the restricting member to retract the trailing end restricting member toward the tray, and the engagement between the pressing member and the engaging portion of the trailing end restricting member as the trailing end restricting member retracts. The trailing edge regulating member is returned to its original position after being released, and then the trailing edge of the newly introduced sheet is pressed toward the retracted portion of the tray by the pressing member .

Since the pressing member presses the rear end portion of the sheet toward the retracted portion of the seating surface of the sheet, the rear end portion of the sheet can be bent in a direction opposite to the rising direction due to the curl. Curling can be easily corrected.
For this reason, even after the pressing by the pressing member is released, the curl is less likely to be restored than when the sheet is pressed against the conventional flat mounting surface, and the trailing edge of the sheet may block the sheet introduction position. Is significantly reduced, and a smooth loading operation can be performed.

Here, when the pressing member is in the second position, it is desirable that a space between the pressing member and the rear end regulating member is an introduction path for a newly introduced sheet.
Also, the receding portion of the placing surface, it is desirable to have an inclined surface retreat amount gradually increases toward the trailing edge of the sheet which is the placement.
Furthermore, the pressing surface of the pressing member is flat, and the pressing member is disposed so as to press the rear end portion of the sheet against the inclined surface in a state where the inclined surface and the pressing surface are parallel at the first position. It is desirable that

Moreover, it is preferable that the inclination angle of the inclined surface with respect to the main surface of the mounting surface is 5 [°] or more and 50 [°] or less.
Here, it is desirable that the maximum retraction amount of the retracting portion from the main surface of the mounting surface is in a range of 5 [mm] to 30 [mm].
Moreover, it is desirable to provide a sheet introducing means for introducing the sheet along the placement surface.

The tray is preferably inclined such that, of the both ends in the sheet introduction direction, the end closer to the introduction position by the sheet introduction means is higher than the other end.
Further, the tray includes positioning means for positioning the sheets in the vertical direction so that the rear end portions of the sheets of different sizes are located in a region corresponding to the retreat portion with respect to the sheets of different sizes. It is desirable.

  The present invention may be a post-processing device that includes the sheet stacking device and stacks a plurality of recording sheets discharged from the image forming apparatus on a tray and performs post-processing on the recording sheets.

1 is a schematic diagram showing a configuration of a copying machine provided with a post-processing apparatus according to an embodiment of the present invention. It is a partially cutaway perspective view showing the configuration of the post-processing apparatus. It is a principal part enlarged view of the said post-processing apparatus. (A)-(d) is a figure which shows the operation | movement condition of a post-processing apparatus. It is a principal part enlarged view of the said post-processing apparatus. (A)-(d) is a figure which shows the operation | movement condition of the post-processing apparatus which concerns on a modification.

Hereinafter, a digital copying machine provided with a post-processing apparatus according to the present invention will be described as an example.
FIG. 1 is a schematic view of the digital copying machine (hereinafter simply referred to as “copying machine”) 1.
As shown in the figure, the copying machine 1 is provided with a post-processing unit 5 on the left side of the image forming apparatus main body 2. The image forming apparatus main body 2 is configured by stacking an image reading unit 3 and a document conveying unit 4 in this order on a printer unit 2b.

The document transport unit 4 reads the image and discharges the document placed on the document tray 4a to the document discharge tray 4b while transporting the document to the image reading surface of the image reading unit 3 described later. This is used when performing through-type image reading.
When the image reading unit 3 performs sheet-through image reading, the reflected light of the light irradiated toward the image reading surface is received by an unillustrated CCD sensor via an optical lens to generate image data. It has a known configuration.

The printer unit 2b is a known electrophotographic type, and performs a series of operations such as exposure, development, transfer, and fixing of a photosensitive drum, and records image data output from the image reading unit 3 as a recording sheet. Is printed and conveyed to the post-processing unit 5.
The operation panel unit 12 includes, for example, a numeric keypad and a liquid crystal display, and displays information to the user and receives instructions from the user.

The post-processing unit 5 executes a stapling process on the recording sheet printed by the printer unit 2b based on a user instruction received by the operation panel unit 12, and then discharges the sheet to the paper discharge tray 5b.
More specifically, when an instruction to execute stapling is received from the operation panel unit 12, a part of the recording sheet sent by the paper discharge roller pair 2 a of the printer unit 2 b is, for example, discharged from the post-processing unit 5. The recording sheet is introduced into the post-processing unit 15 by reversing the paper discharge roller pair 5c and switching back the recording sheet at the timing when it is drawn into the roller pair 5c.

Of course, the recording sheet may be directly introduced into the post-processing unit 15 without being switched back.
The post-processing unit 15 performs a stapling process on the bundle of recording sheets stacked on the tray, and discharges the bundle of recording sheets on which the stapling process has been completed to the discharge tray 5b via the discharge roller pair 5d. To do.

If there is no instruction to execute stapling from the user, the recording sheet discharged from the printer unit 2b is discharged as it is to the paper discharge tray 5a.
FIG. 2 is a partially cutaway perspective view showing the configuration of the post-processing unit 15.
As shown in the figure, the post-processing unit 15 includes an introduction roller pair 20, a rear end regulating unit 30, a guide member 50, a tray 60, a staple unit 80, a driving unit 70, and a driving unit 90. .

The introduction roller pair 20 is driven by a drive source (not shown), and the other is a roller that is driven and rotated. The recording sheet S1 that is switched back by the discharge roller pair 5c is introduced into the tray 60. To do.
The guide member 50 guides the introduced recording sheet S1 to the tray 60, and presses the recording sheet placed on the tray 60 toward the retracted portion 60c of the placing surface 60a of the tray 60, thereby recording the recording sheet. Is a plate-like member that corrects the curl that is generated on the main body side frame of the post-processing unit 5 via a rotating shaft 51 attached to the lower side (Z ′ direction side) edge thereof. Further, it is rotatably supported by a bearing portion (not shown).

Note that the post-processing apparatus according to the present embodiment has a problem of curling that closes the position where the recording sheet is introduced into the tray 60. Therefore, the curl described below has a central portion in the direction in which the recording sheet is introduced in the tray 60. Means a curl (so-called back curl) that comes into contact with a later-described placement surface 60a and floats from the placement surface 60a with both end portions in the recording sheet introduction direction being warped.
One end of the rotation shaft 51 is connected to the drive unit 70, and thereby the guide member 50 is driven to swing.

By this swinging operation, the guide member 50 is configured to press the rear end portion of the recording sheet described in the tray 60 and correct the curl.
As a drive source of the drive unit 70, for example, a motor capable of controlling the rotation angle such as a stepping motor is desirable.
The surface of the guide member 50 on the tray 60 side is a guide surface 50 a that guides the recording sheet S <b> 1 introduced by the introduction roller pair 20.

At the end of the guide member 50 opposite to the rotation shaft 51 (Z side), an engaging portion 52a is formed on the front side, and four notches 53 are formed at predetermined intervals along the Y direction. (In FIG. 2, only two locations on the front side are shown.)
The notch 53 is provided in order to avoid interference with the tongue-shaped portion 31 b of the trailing edge regulating member 31 during the pressing operation of the trailing edge of the recording sheet described later in the trailing edge regulating unit 30.

The trailing edge regulating unit 30 is for regulating the trailing edge of the recording sheet placed on the tray 60 (the edge on the opposite side of the introduction roller) from floating due to curling. Details will be described later.
The tray 60 is configured to stack a plurality of recording sheets sequentially on the placement surface 60a so that the ends of the recording sheets are aligned.

The mounting surface 60a includes a flat main surface portion 60b and a receding portion 60c which is disposed adjacent to the side of the main surface portion 60b closer to the introduction roller pair 20 and recedes in a direction away from the sheet than the main surface portion 60b. 60b is inclined at an angle of θ1 with respect to the horizontal plane.
The value of this angle θ1 is preferably 40 ° or more so that the apparatus size in the horizontal direction can be reduced and the leading edge of the recording sheet can be aligned using gravity. In order to prevent the waist from losing its own weight and causing undulations, it is desirable to set it to 80 [°] or less.

Further, the tray 60 has a bottom plate 61 for adjusting the position of the leading end of the recording sheet below (Z ′ direction side).
The bottom plate 61 is driven up and down by the drive unit 90. This raising / lowering operation is performed in order to adjust the position of the trailing edge of different sheets according to the sheet size and to make the trailing edge of each recording sheet bundle S2 face a retreating portion 60c of the tray 60 described later. It is.

Thereby, even when recording sheets having different sheet sizes are introduced into the tray 60, the rear end portion of the recording sheet of each size can be deformed along the shape of the retreating portion in accordance with the pressing operation of the guide member 50. The curl generated at the rear end can be corrected.
Further, the bottom plate 61 is configured to be retracted to the outside in order to discharge the bundle of recording sheets for which the stapling process has been completed from the bottom of the tray 60.

The drive unit 90 has an endless belt 93 wound around a drive roller 91 that is rotationally driven by a drive source (not shown) and a driven roller 92 that is rotatably provided, and the bottom plate 61 of the tray 60 includes the endless belt 61. 93 is fixed to the belt so as to maintain a state substantially orthogonal to the running direction of the belt, and as the unsupported belt 93 rotates, the above-described lifting / retreating operation is performed.
The staple unit 80 performs a staple process on the near-side corner portion of the bundle of recording sheets placed on the tray 60.

Here, a moving mechanism for moving the staple unit 80 in the vertical direction of the tray 60 may be provided so as to perform stapling processing at two locations along the side edge of the recording sheet bundle. Since the staple unit 80 itself has a known configuration, further description is omitted.
The sheet bundle stapled by the post-processing unit 15 is discharged from the post-processing unit 15 when the bottom plate 61 is retracted, and is discharged onto the paper discharge tray 5b via the paper discharge roller pair 5d.

<Configuration of rear end regulating unit>
As described above, the trailing edge regulating unit 30 corrects the curl so that the trailing edge of the recording sheet placed on the tray 60 (the edge on the side opposite to the introduction roller) does not float, and introduces the recording sheet. This is for preventing the mouth from being blocked, and includes a rear end regulating member 31, an engaging lever 32, a biasing member 33, a posture holding member 34, and the like.

The rear end regulating member 31 includes a rotation shaft 31a extending in the Y-axis direction and four tongue-shaped portions 31b extending in one direction orthogonal to the rotation shaft 31a. The rotation shaft 31a is rotatably supported by a frame (not shown) via the bearing portion 42.
The engaging lever 32 is attached to the front end portion of the rotating shaft 31 a and engages with the engaging portion 52 a of the guide member 50 when the guide member 50 is swung toward the tray 60. The rear end regulating member 31 is pivoted and rotated toward the tray 60.

3A is an enlarged perspective view of the periphery of the engagement lever 32, and FIG. 3B is a view when the engagement lever 32 is cut along a plane including the axis of the rotation shaft 31a. It is sectional drawing.
As shown in FIG. 3A, the engaging lever 32 has an inverted L shape in which the lever portion 32b and the arm portion 32e are orthogonal to each other.
Here, since the arm portion 32e is urged upward in the drawing by the urging member 33 such as a tension coil spring, the engagement lever 32 is given a rotational moment that swings clockwise.

Of course, other elastic members such as rubber and resin may be used as the urging member 33.
An engaging pin 31c is erected on the outer side of the portion of the rotating shaft 31a where the engaging lever 32 is attached, and the engaging pin 31c is erected in a direction orthogonal to the rotating shaft 31a. By abutting with a stopper 41 provided on a main body frame (not shown), the swing angle of the rear end regulating member 31 in the direction away from the tray 60 is regulated.

Further, as shown in the cross-sectional view of FIG. 3 (b), the engaging lever 32 is moved by the support pin 35 in a state where the rotating shaft 31a of the rear end regulating member 31 is loosely fitted in the through hole 32a. It is supported so as to be swingable in the axial direction.
As shown in FIG. 3B, the engaging lever 32 has a groove 32d into which an end of a posture holding member 34 made of a compression coil spring is inserted. Usually, the posture holding member 34 is inserted. By fitting, the posture is held such that the longitudinal direction of the lever portion 32b is orthogonal to the rotation shaft 31a by the appropriate rigidity of the posture holding member 34.

In FIG. 3A, the compression coil spring, which is the posture holding member 34, is partially omitted so that the shape of the engagement lever 32 can be easily understood. To the groove 32d of the engaging lever 32.
Both the X and X ′ side surfaces of the lever portion 32b are portions where the engaging portions 52a of the guide member 50 are engaged, and the X side engaging surface is a flat surface parallel to the extending direction of the rotating shaft 31a. However, as shown in FIGS. 3A and 3B, the portion of the surface on the X ′ side that contacts the engaging portion 52a gradually decreases in thickness in the X ′ direction as it proceeds in the Y direction. When the guide member swings toward the opposite side of the tray 60 in a state where the engaging pin 31c is in contact with the stopper 41 as shown in FIG. The engaging portion 52a comes into contact with the tapered portion 32c, and due to the taper action of the tapered portion 32c, a component force to be pressed in the axial direction is generated on the contact surface, and the lever portion 32b side becomes the urging force of the posture holding member 34. Run away in the Y 'direction Tilt in the direction of arrow B.

As a result, the engagement between the engaging portion 52a and the lever portion 32b is released, and only the guide member 50 swings in the X-axis direction and returns to the original position (first position).
FIGS. 4A to 4D are diagrams illustrating the operation status of each member in the post-processing unit 15.
Normally, as shown in FIG. 4A, the guide member 50 has a locus (hereinafter referred to as “introduction locus”) R1 on the X direction side when the recording sheet S1 is introduced by the introduction roller pair 20 (hereinafter referred to as “introduction locus”). Hereinafter, it is referred to as “guide position”.

Further, as shown in FIG. 4A, the rear end regulating member 31 is positioned between the guide surface 50a of the guide member 50 and the placement surface 60a of the tray 60 (hereinafter referred to as “regulated position”). ").
At this time, the recording sheet S <b> 1 introduced by the introduction roller pair 20 is guided to the tray 60 side by the guide surface of the guide member 50. The trailing edge regulating member 31 regulates the lifting of the trailing edge Q of the stacked recording sheet bundle S2 and prevents the trailing edge Q from closing the recording sheet inlet P1.

When the introduction of the recording sheet S1 is completed, the drive unit 70 (see FIG. 2) swings the upper end portion of the guide member 50 in the X ′ direction, as shown in FIG. 4B.
At this time, as shown in FIG. 5, the engaging portion 52 a of the guide member 50 swings while engaging with the lever portion 32 b, so that the tongue-like portion 31 b of the rear end regulating member 31 is also interlocked with the guide member 50. And swings.

Thereby, as shown in FIG.4 (b), the tongue-shaped part 31b of the rear-end control member 31 rotates counterclockwise.
The guide member 50 swings and the trailing end regulating member 31 rotates, and at a certain point, the tongue portion 31b does not engage with the trailing end portion Q of the stacked recording sheet bundle S2, and its position The restriction is removed and the newly introduced recording sheet is superimposed on the stacked recording sheet.

Along with this swinging operation, the engaging position of the engaging portion 52a of the guide member 50 and the engaging position of the lever portion 32b gradually move away from the respective rotation centers, and the entire newly introduced recording sheet is stacked. Their arrangement and length are set so that the two are disengaged immediately after being overlaid on the used recording sheet.
In this way, when the engagement between the engaging portion 52a of the guide member 50 and the lever portion 32b is released, the rear end restricting member 31 returns to the original restricting position by the urging force of the urging member 33 (FIG. 4 (c)).

As described above, the mounting surface 60a of the tray 60 is provided with the retreating portion 60c, and the guide member 50 continues to swing even after the engagement with the rear end regulating member 31 is released, and recording is performed. The rear end portion of the sheet S1 is pressed together with the recording sheet bundle S2 toward the retracted portion 60c (second position).
As shown in FIG. 4B, the retreating portion 60c is located at a position near the leading end side (lower end side) of the recording sheet by a length L1 from the trailing end of the recording sheet in the loaded state. The boundary portion 60d extends in a direction orthogonal to the recording sheet introduction direction (Y-axis direction), and the main surface portion 60b starts from the boundary portion 60d. The inclined surface 60e has a gradually increasing amount as it moves away from the center (Z direction). After the amount of retraction from the main surface portion 60b reaches D1, the amount of retraction is not limited even if the amount of retreat is Z. The configuration is maintained.

As a result, when the rear end portion of the recording sheet S1 and the rear end portion of the recording sheet bundle S2 are pressed against the retreating portion 60c by the guide member 50, the rear end portion starts from the vicinity of the boundary portion 60d as the starting point. Bends side and curls are corrected.
Here, if the value of L1 is too small, the curl correction range becomes small, and the effect of preventing the trailing edge of the recording sheet from blocking the inlet P1 of the recording sheet cannot be obtained sufficiently.

On the other hand, if L1 is too large, a portion that does not require curl correction is pressed against the inclined surface portion 60e by the guide member 50, and the curl correction at a required portion cannot be performed.
From such a viewpoint, the value of L1 is preferably set to 20 [mm] or more and 50 [mm] or less. In this embodiment, it is set to 35 [mm].
Further, the value of the angle θ2 of the inclined surface 60e with respect to the main surface portion 60b is set as follows.

That is, when the angle θ2 is too small, the curl correction is insufficient, and when the angle θ2 is too large, when the post-processed recording sheet is discharged by sliding the bottom plate 61 downward, the trailing edge of the recording sheet is removed. There is a possibility that the bent portion is caught by the inclined surface 60e and is difficult to be discharged, or the output recording sheet may be folded at the boundary 60d.
In order not to cause such inconvenience, the value of the angle θ2 is preferably 5 [°] or more and 50 [°] or less.

Further, the retraction amount D1 of the retreating portion 60c increases as the value of the angle θ2 and the length Ls of the inclined portion in the sheet introduction direction increases (see FIG. 4A), and when these values are small, D1 Since the values also become smaller, these values and the apparatus size are appropriately determined, but a range of 5 [mm] or more and 30 [mm] or less is appropriate.
However, the retreating portion 60c only needs to have the inclined surface 60e as described above, and a plane portion parallel to the main surface portion 60b as shown in FIG. Alternatively, only the inclined surface 60e may be used.

The guide member 50 is parallel to the inclined surface 60e, and when the distance between them is D2, the rotation operation is stopped.
The value of the distance D2 is set to the maximum number of recording sheets placed on the tray 60 × the maximum thickness of the recording sheet [mm], and is set to 2 [mm] here.
Thereby, since a large force is not applied to the recording sheet, scratches and wrinkles are hardly generated.

Further, since the guide member 50 presses the recording sheet in a state substantially parallel to the inclined surface 60e, it can be pressed against the inclined surface 60e by contacting the recording sheet with a surface instead of a line, and the effect of curl correction is increased.
Subsequently, the drive unit 70 (see FIG. 2) rotates in the reverse direction to swing the upper end portion of the guide member 50 in the X direction and return to the above-described guide position (FIG. 4D).

At this time, since the curling is corrected by the pressing operation of the guide member 50 described above, even if the trailing end Q of the recording sheet is slightly lifted, the amount is small, and until the recording sheet inlet P1 is closed. Not reached.
While the guide member 50 is returning to the guide position, the engaging portion 52a contacts the tapered portion 32c of the lever portion 32b. However, as described with reference to FIG. 3, the lever portion 32b falls in the axial direction. The engagement between the portion 52a and the lever portion 32b is completely released, and only the guide member 50 can swing in the X-axis direction (see FIG. 3).

Then, when the guide member 50 returns to the original guide position, the drive of the guide member is stopped.
At this time, the return of the guide member 50 to the guide position is performed, for example, by setting a large amount of rotation of the drive unit 70 at the time of return, making sure that the guide member 50 is in contact with a stopper (not shown), and rotating in the X direction. It can be realized by stopping.

  Further, every time the guide member 50 returns to the guide position, the count value of the drive pulse of the drive unit 70 is reset to 0, and from this guide position, the guide member 50 moves to the placement surface 60a of the tray 60 and hits it. By providing the drive unit 70 with a sufficient number of drive pulses for contact, the operations shown in FIGS. 4A to 4C can be performed without detecting the position of the guide member 50.

Of course, in order to detect that the guide member 50 is at the guide position, a home position sensor such as a reflective optical sensor may be provided and controlled.
As described above, according to the present embodiment, the portion corresponding to the sheet rear end portion of the recording sheet mounting surface is retracted, and by pressing the recording sheet rear end portion toward the retracted portion by the guide member, The curl of the recording sheet can be effectively corrected, and the risk of floating and preventing the sheet introduction port can be extremely reduced.
<Modification>
The present invention is not limited to the above-described embodiment, and the following modifications can be implemented.

(1) In the above-described embodiment, the guide member 50 is a plate-like member extending in the Y-axis direction. However, the guide member 50 is not limited to this, and for example, the introduction of the recording sheet can be guided and the introduced recording sheet can be pressed down. Any shape can be used as long as it can be formed.
(2) In the above embodiment, the configuration in which the guide member 50 and the rear end regulating member 31 are swung has been described. However, the present invention is not limited to this.

For example, the guide member and the sheet rear end position regulating member may be slid.
FIGS. 6A to 6D are diagrams showing the operation states of the members in the post-processing unit 115 adopting such a configuration.
First, the configuration of each unit of the post-processing unit 115 will be described with reference to FIG.
In addition, about the same structure as the post-processing part 15 in the said embodiment, the same code | symbol is attached | subjected and below, the structure different from the post-processing part 15 is mainly demonstrated.

As shown in FIG. 6A, rails 235 and rails 255 are provided that increase in distance from each other as they proceed in the X ′ direction.
The rear end regulating member 230 and the guide member 250 are slidably provided on the rail 235 and the rail 255, respectively.
Further, the rail 235 has a stopper 241 that abuts against the rear end regulating member 230 and regulates the position at the end in the X-axis direction.

Further, a biasing member 233 such as a spring or rubber for biasing the rear end regulating member 230 toward the stopper 241 is provided.
In addition, a drive unit 280 made of a belt drive mechanism or the like that moves the guide member 250 along the rail 255 is provided.
The positions of the rear end regulating member 230 and the guide member 250 in FIG. 6 (a) are substantially the same positions as the positions of the rear end regulating member 31 and the guide member 50 in FIG. 4 (a), respectively. It becomes a regulation position and a guide position.

When the guide member 250 slides to the X ′ direction side from this guide position, the recording sheet S1 is pushed into the placement surface 60a side of the tray 60 and reaches the position shown in FIG. 6B. The guide member 250 contacts the rear end regulating member 230 and slides it in the X ′ direction.
As described above, since the rail 235 and the rail 255 are provided so that the distance between the rail 235 and the rail 255 increases in the X ′ direction, the distance between the contact portions of the rear end regulating member 230 and the guide member 250 in the Z-axis direction. Then, the contact state is gradually released, and only the rear end regulating member 230 returns to the regulated position by the urging force of the urging member 233 as shown in FIG. 6C.

  When the guide member 250 continues to slide, the rear end portion of the recording sheets S1 is pressed against the recording sheet bundle S2, as shown in FIG. 6C. A portion of the guide member 250 corresponding to the inclined portion 60e of the tray 60 is parallel to the inclined surface of the inclined portion 60e, and recording is performed on the surface regardless of the number of stacked recording sheets due to sliding movement. The entire rear end portion of the recording sheet can be pressed against the inclined surface 60e by contacting the sheet.

Thereafter, the drive unit 280 is reversed, and the guide member 250 is slid in the X direction to return to the guide position.
The guide member 250 part comes into contact with the rear end regulating member 230 at the regulation position in the middle of returning to the guide position, but one of the abutting parts, for example, the abutting part on the guide member 250 part side As shown in FIG. 6 (e), 252a swings and avoids engagement only when a force is applied in the clockwise direction by contacting the contact portion 232b on the rear end regulating member 230 side. Thus, only the guide member 250 portion can be further slid in the X direction.

The contact portion 252a is urged so as to always swing counterclockwise by a spring (not shown), and returns to its original position when the engagement is released.
As described above, the rear end regulating member and the guide member may be configured not only to rotate but also to slide.
(3) In the above embodiment, the guide member 50 continues to swing even after the engagement with the rear end regulating member 31 is released, and the guide member 50 and the inclined surface 60e become parallel, The rear end portion of the recording sheet S1 is pressed against the recording sheet bundle S2 until the mutual distance reaches D2, but the present invention is not limited to this, and the guide member 50 and the inclined surface 60e may not be completely parallel. Absent. In short, it is possible to correct the curl to such an extent that the inlet is not blocked as long as the trailing end can be bent in the pressing direction by pressing the trailing end of the recording sheet.

The receding portion 60c includes the inclined surface 60e, but such an inclined surface 60e may not be provided. For example, the receding portion 60c is cut in the thickness direction of the placement surface 60a at the boundary portion 60d. A wall may be formed and a step may be formed.
In that case, in order to obtain the same curling correction effect as that of the post-processing unit 15 in the above-described embodiment, the depth of the step is preferably set to 5 [mm] or more and 30 [mm] or less.

(4) In the above embodiment, the rear end regulating member 31 is provided. However, the rear end regulating member 31 is not necessarily essential.
Even if the guide member 50 only presses the rear end of the recording sheet in the state described in the tray 60, the rear end portion of the recording sheet is moved to the recording sheet due to the presence of the retreating portion 60c provided on the placement surface 60a of the tray 60. The curl generated in the trailing edge of the recording sheet can be effectively corrected by bending in the direction away from the introduction port P1, and even if the curl is slightly restored after the pressure is released Since the distance between the sheet introduction port P1 and the trailing edge of the recording sheet is larger than when the recording sheet is pressed against the conventional flat mounting surface 60a, as long as a normal recording sheet is used, This is because the end portion does not float up to the inlet.

However, for example, when a recording sheet with a high recycled paper usage rate and an adverse condition such as high temperature and high humidity overlap, the degree of curling of the recording sheet becomes extremely large, and the curling is sufficiently corrected by pressing the guide member. Since it cannot be said that there is no case where it cannot be performed, in the said embodiment, the rear-end regulation member 31 is provided as an auxiliary | assistant in case of an emergency.
(5) In the above embodiment, the guide member 50 has a function of guiding the introduced recording sheet to the tray 60 and a function of pressing the recording sheet toward the placement surface 60 a of the tray 60. However, it is not necessary to have the function of guiding the introduced recording sheet to the tray 60. In short, as long as it has a function as a pressing member that presses the recording sheet toward the mounting surface 60a of the tray 60. Good.

(6) In the above embodiment, the example in which the post-processing unit 5 (post-processing apparatus) according to the present invention is applied to a digital copying machine has been described. However, the configuration in which the post-processing unit 5 is attached to the printer unit 2b. You may apply to.
(7) In the above embodiment, the post-processing unit 5 executes the stapling process on the recording sheet printed by the printer unit 2b. However, the present invention is not limited to this. For example, the post-processing unit 5 is replaced with the stapling process. Alternatively, a punching process may be used in which holes are formed in a plurality of recording sheets.

Alternatively, the present invention can also be applied to a simple sheet stacking apparatus in which a plurality of introduced sheets are sequentially stacked on a tray.
Further, the contents of the above embodiment and the above modification may be combined as much as possible.

  The present invention can be widely applied to a sheet stacking apparatus that sequentially stacks a plurality of introduced sheets on a tray and a post-processing apparatus including the sheet stacking apparatus.

DESCRIPTION OF SYMBOLS 1 Copier 2 Image forming apparatus main body 2a Paper discharge roller pair 2b Printer part 3 Image reading part 4 Document conveyance part 4a Document tray 4b Document discharge tray 5 Post-processing unit 5a, 5b Paper discharge tray 5c, 5d Paper discharge roller pair 12 Operation panel portion 15, 115 Post-processing portion 20 Introducing roller pair 30 Rear end regulating unit 31, 230 Rear end regulating member 31a, 51 Rotating shaft 31b Tongue portion 31c Engaging pin 32 Engaging lever 32a Through hole 32b Lever portion 32c Tapered portion 32d Groove portion 32e Arm portion 33, 233 Biasing member 34 Posture holding member 35 Support pin 41, 241 Stopper 42 Bearing portion 50, 150, 250 Guide member 50a Guide surface 52a Engagement portion 53 Notch portion 60 Tray 60a Placement Surface 60b Main surface portion 60c Retreating portion 60d Boundary portion 61 Bottom plate 7 , 90,280 driver 80 stapling unit 91 drives roller 92 driven roller 93 the endless belt 232b, 252a abutting portion 235 and 255 rail

Claims (10)

A sheet stacking device that sequentially introduces and stacks a plurality of sheets onto a tray,
A tray having a placement surface on which the introduced sheet is placed, and a retreat portion formed by retreating a region corresponding to the rear end portion of the sheet in the placement state on the placement surface;
A pressing member that is movably provided between a first position and a second position sandwiching the introduction position of the sheet, and that presses the rear end portion toward the retracted portion in accordance with the movement to the first position;
When the pressing member is in the second position, the pressing member is interposed between the pressing member and the retracted portion of the tray, and the trailing edge of the sheets stacked on the tray is lifted to prevent the sheet introduction position from being blocked. A rear end regulating member that regulates,
Drive means for selectively moving the pressing member to first and second positions;
Equipped with a,
The rear end regulating member can be retracted toward the rear end side of the tray,
When the pressing member moves from the second position to the first position, it engages with the engaging portion of the rear end restricting member and retracts the rear end restricting member toward the tray side, thereby restricting the rear end. As the member retreats, the engagement between the pressing member and the engaging portion of the rear end regulating member is released and the rear end regulating member returns to the original position, and then newly introduced by the pressing member. A sheet stacking apparatus that presses a rear end portion of a sheet toward a retracted portion of a tray . The space between the pressing member and the rear end regulating member serves as an introduction path for a newly introduced sheet when the pressing member is in the second position. Sheet stacking device. 3. The sheet stacking apparatus according to claim 1, wherein the receding portion on the placement surface has an inclined surface in which the receding amount gradually increases toward the rear end of the placed sheet. 4. The pressing surface of the pressing member is flat, and the pressing member is arranged to press the rear end portion of the sheet against the inclined surface in a state where the inclined surface and the pressing surface are parallel at the first position. The sheet stacking apparatus according to claim 3 . The sheet stacking apparatus according to claim 4 , wherein an inclination angle of the inclined surface with respect to the main surface of the mounting surface is 5 ° or more and 50 ° or less. The sheet stacking according to any one of claims 1 to 5 , wherein a maximum retraction amount from the main surface of the placement surface of the retreating portion is in a range of 5 [mm] or more and 30 [mm] or less. apparatus. Sheet stacking apparatus according to any one of claims 1 to 6, characterized in that it comprises a sheet introducing means for introducing along the mounting surface of the sheet. The tray of claim of both end portions in the sheet introducing direction and an end portion of the side near the introducing position by the sheet feeding means is inclined so as to be above the other end 7 The sheet stacking apparatus described in 1. The tray is provided with positioning means for positioning the sheets in the vertical direction with respect to sheets of different sizes so that the rear end of each size of the sheets is located in a region corresponding to the retracted portion. The sheet stacking apparatus according to claim 8 , wherein the sheet stacking apparatus is characterized. Including a sheet stacking apparatus according to any one of claims 1 to 9, by stacking a plurality of recording sheets discharged from the image forming apparatus to the tray, the post-processing apparatus that performs post-processing on the recording sheet.

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