JP2001206613A - Sheet loading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet loading device capable of preventing occurrence of transport troubles such as a sheet discharge failure, a jam and the like even in the case of loading a large number of sheets having a projecting part discharged from an image forming apparatus, a sheet post-treating unit or the like, and correctly loading the loaded sheets with stability. SOLUTION: In this sheet loading device having discharge means 12, 52 for discharging sheets, and a loading means 3 for receiving sheets discharged from the discharge means and loading the same, the loading means is provided with at least two split loading members 3a1, 3a2 split in the cross direction orthogonal to the sheet discharge direction, and at least one of the split loading members is adapted to elevate independently of the other member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking apparatus on which sheets are discharged and stacked, for example, a copying machine, a printer, a facsimile apparatus, a printing machine, etc., which form an image on a sheet and discharge and stack the sheet. The present invention relates to an image forming apparatus, a sheet post-processing apparatus for performing post-processing of a sheet, and an image forming apparatus including the sheet post-processing apparatus.

[0002]

2. Description of the Related Art Copiers, printers, facsimile machines,
In an image forming apparatus such as a printing machine, or a sheet post-processing apparatus for performing post-processing such as stapling, clipping, punching, and cutting on a sheet such as recording paper discharged from the image forming apparatus, etc. After the sheet is subjected to a required process, the sheet is discharged to the outside of the apparatus main body, and is stacked on a stacking member such as a discharge tray. When a large number of sheets are discharged and stacked on the stacking member by the job processing by each device main body, if the stacking member is fixed at a fixed height position, the discharging operation is continued in response to the increased stacking amount. For this reason, various sheet stacking apparatuses have been proposed in which the position of the stacking member is lowered in accordance with an increase in the amount of sheets stacked on the stacking member. That is, in the sheet stacking device, when the position of the upper surface of the sheet increases with an increase in the amount of sheets stacked on the stacking member, the stacked sheets close the sheet discharge port on the apparatus main body side, and the smoothness of sheet discharge, and It is difficult to ensure loading stability and consistency. For this reason, there is known a sheet stacking apparatus provided with a sensor that detects a change in the height position of the upper surface of the sheet based on the change in the height position of the trailing edge of the stacked sheet in the discharge direction. Each time the sensor detects that the position of the upper surface of the sheet has reached the predetermined limit position, the sheet stacking device is configured to operate the elevation drive means to lower the entire stacking member by a predetermined height. I have. by the way,
Deformation habits such as upward curl and folding may be formed on sheets discharged one by one after undergoing required processing in an apparatus body such as an image forming apparatus and a sheet post-processing apparatus. The formation position and mode of the deformation habit are not uniform according to the type of processing to be received in the apparatus main body, the habit of each device, and the like, and a sheet having the deformation habit is partially discharged onto the stacking member and stacked. Then, a part of the upper surface of the stacking sheet projects greatly upward.

[0003] A bundle of sheets in which staples are driven into the trailing end (a corner or a position along the trailing edge) in the discharge direction by a sheet post-processing apparatus is staple-sized by the thickness of the staples. Since the portion is thicker than the other portions, when a bundle of sheets stapled at the same location is stacked on the loading member, only the staple portion protrudes excessively above the other portions. In addition, a sheet that has been punched or cut by a rotary blade has a similar protruding portion because the periphery of the perforated portion and the cut portion are easily protruded. When the above-mentioned deformation habit or post-processing such as staples causes the upwardly projecting portions to be formed on a part of the discharged and stacked sheets on the stacking member, these projecting portions may extend along the rear edge in the discharging direction, for example. When the sheet is formed at the position, it closes the discharge port of the apparatus main body, and if it is located on the discharge path of the sheet discharged from the discharge port, it may cause problems such as a sheet discharge failure and a stacking defect. . However, since the formation position of the above-described protruding portion is changed by changing the sheet size and the binding position, the presence of the protruding portion can be always detected by an arbitrary position, for example, the above-described sensor arranged in the center of the sheet in the width direction. Not necessarily. Therefore, when the sensor detects the flat surface of the upper surface of the sheet at a position lower than the projecting portion first despite the fact that the projecting portion is formed, the projecting portion has already detected the discharge port on the apparatus body side. Despite the closing, the operation of lowering the loading member is not performed in a timely manner.

Next, this will be further described with reference to the drawings. That is, FIG. 19 is a perspective view showing a state in which a staple-bound bundled sheet is discharged from a discharge port of an apparatus body such as a sheet post-processing apparatus, and FIG. 20 shows a state in which the bundled sheet is stacked. FIG. 21 is a front view, and FIG. 21 is a perspective view showing a state in which a sheet having a deformed portion such as a curl at a rear end corner is discharged and stacked, and FIG. 22 is a diagram illustrating a state where a sheet having the deformed portion is stacked. It is a front view showing the state performed. The sheet bundle (P) discharged from the discharge port 112 of the sheet post-processing apparatus 110 shown in FIG. 19 is stapled by a binding unit (not shown) located in the sheet post-processing apparatus 110 at the rear end corner in the discharge direction. The needle (S) penetrates. When this bundle of sheets is stacked on a stacking member (discharge tray) of the sheet stacking apparatus 100, a portion where a staple is pierced projects upward as shown in FIG. The protruding portion (E) protrudes largely above the other flat portion of the seat upper surface. Reference numeral 105 denotes a sensor with a filler disposed just below the center in the longitudinal direction of the discharge port 112 to detect the height of the upper surface of the sheet. When the sensor with the filler 105 detects the upper surface of the sheet, a loading sensor described later is used. The member 3 descends by a predetermined distance. Further, the image forming apparatus 15 shown in FIG.
In the case where a deformation habit such as curl, folding, wrinkle, or the like is formed in a part of the image-formed sheet (p) discharged one by one from the zero discharge port 152, for example, in the rear corner (T). FIG.
As shown in (1), the deformed portions of the stacked sheets are accumulated and bulky, and only this portion protrudes upward. Reference numeral 155 denotes a sensor with a filler similar to the sensor 105 shown in FIG. For this reason, for example, as shown in FIG. 23, if the sheet bundle (P) provided with the protrusion (E) at one corner of the rear edge continues to be stacked on the stacking member 103, the protrusion (E)
Quickly closes the discharge port 112 of the post-processing device 110, and the sheet bundle newly discharged from the discharge port 112 becomes an obstacle, causing a jam or the like due to a defective discharge. The presence of the protruding portion (E) is determined by the sensor 1 located at the center.
05 cannot be detected. This means
The same applies to a case where a deformed portion is present at a corner of a sheet discharged one by one from the discharge port 152 of the image forming apparatus 150.

As described above, the sensors 105 and 155 for detecting the position of the upper surface of the sheet are provided at positions corresponding to the center of the sheet in the width direction. Even when the stacking member is lowered when it reaches the position, if the position of the protrusion (E) is at a position other than the center, the protrusion (E) interferes with the discharge port 112 before detection. Status or loading failure. In particular, the position at which the protrusion (E) is formed is not uniform due to various uncertain factors such as the sheet size, the post-processing method, and the internal state of the apparatus main body. The detection does not necessarily mean that the loading member is lowered. That is, when the sensor detects that the upper surface of the sheet other than the protruding portion has reached the limit height, the protruding portion is already in a state of interfering with the discharge port, and a discharge failure and a stacking defect often occur. . If the distance between the stacking member 103 and the discharge port 112 is set to be large in advance as shown in FIG. 24 in order to solve the problem as shown in FIG. 23, a stapled bundle of sheets or In the process in which one sheet is discharged from the discharge port 112, the protruding portion (E) of the already loaded sheet is discharged in a state where the leading end of the lower sheet of the sheet bundle (P) is rolled and rounded (M), and the lower sheet is discharged. Are loaded with their tips broken. This inconvenience also occurs for sheets discharged one by one from the image forming apparatus.

Next, JP-A-7-53115 discloses that
A concave portion is formed in advance on the sheet stacking portion corresponding to the staple position (thick portion) of the sheet bundle discharged from the discharge port of the post-processing device onto the sheet stacking portion, and the thick portion is fitted into the concave portion. A technique has been disclosed in which the staple position is prevented from increasing upward by combining the staple positions. However, in this prior art, only the thick portion formed at the corner of the sheet is locally fitted into the concave portion, so that the projecting of the thick portion upward is completely eliminated. It is not possible.
In particular, in a sheet stacking device for stacking a small number of sheets, the amount of protrusion of the thick portion reduced by fitting into the concave portion can be expected to have some effect in alleviating poor discharge from the discharge port, but a large number of sheets can be expected. In the sheet stacking apparatus for stacking the sheets, the amount of protrusion of the thick portion that reduces the concave portion is insufficient to alleviate the discharge failure. Further, the presence of the thick portion not only causes a conveyance obstacle such as a jam, but also causes the inclination angle of the upper surface of the sheet to be excessive due to accumulation of the thick portion due to stacking of a large number of sheets on the sheet stacking portion. There is a risk that the vehicle may not be able to be loaded correctly, for example, it may lose its seating stability and collapse in the direction of the inclined surface or fall. Also, when the depth of the locally provided recess is made shallow, the effect of reducing the protrusion amount by the thick portion is small, while when the recess is made deep or wide, the loading stability is reduced. The loaded sheet is likely to collapse. Further, since the position of the concave portion is fixed, the sheet stacking section having such a structure can be applied only to an image forming apparatus or a sheet post-processing apparatus in which a sheet size and a staple position to be used are determined in advance. When the sheet size, the staple position, the position of the deformed portion, and the like are changed, the effect of the concave portion at the fixed position is reduced. Next, JP-A-10-330024 discloses that
A plurality of tray upper limit sensors for detecting the height of the trailing edge of the stacked sheets are provided along the width direction of the sheet at the trailing end side of the vertically movable sheet discharge tray, and one of the sensors is in a protruding state. Is detected, the height of the upper surface of the sheet with respect to the discharge port is always kept constant by lowering the discharge tray by a predetermined amount. However, even if the entire discharge tray is lowered when the sensor detects a thick portion such as a staple portion, the projection amount and the steep inclination angle of the thick portion cannot be reduced. Sometimes, the upper sheet loses the stacking stability due to the inclined surface of the protruding portion and collapses in the direction of the inclined surface to drop.

[0007]

As described above, in the conventional sheet stacking apparatus, one of the sheets discharged onto the stacking member from the discharge port of the apparatus main body such as a sheet post-processing apparatus and an image forming apparatus. If there is a staple portion or a deformed portion at one end in the width direction where no sensor for detecting the upper surface of the sheet is present, one end in the width direction of the stacked sheets protrudes upward as a thick portion, and This causes an obstruction to discharge the sheet from the discharge port, and causes the sheets stacked on the stacking member to be misaligned or dropped. On the other hand, conventionally, a concave portion for receiving the thick portion of the sheet at an appropriate position on the stacking member to reduce the protrusion amount is provided, or when the thick portion of the stacked sheet reaches a predetermined height position, Measures such as lowering the stacking member so that the thick portion does not interfere with the discharge port upon detection have been taken.However, none of the measures is insufficient as described above, and the stacked sheet is thick. There was a problem that it could not be loaded correctly due to collapse along the inclined surface of the part. Further, although the upper surface has been detected at a plurality of positions of the trailing edge of the stacked sheet using a plurality of sensors, the stacking member is lowered by a predetermined distance based on the result of detection of the protrusion by one sensor. When the control is sequentially executed, the protrusion amount of the protruding portion becomes excessively large at last, and the stacking stability of the sheets is reduced, and there is a possibility that the load may collapse. Therefore, an object of the present invention is to solve such a problem. That is, even if a large number of sheets having a projecting portion ejected from an image forming apparatus or a sheet post-processing device are stacked, the ejection failure due to the projecting portion blocking the ejection opening,
It is another object of the present invention to provide a sheet stacking apparatus capable of preventing conveyance troubles such as jams from occurring, and capable of correctly stacking stacked sheets while maintaining stability.

[0008]

In order to achieve the above object, according to the present invention, there is provided a sheet discharging means for discharging sheets, and a sheet stacking means for receiving and stacking the sheets discharged from the discharging means. Wherein the sheet stacking means comprises at least two divided stacking members divided in a width direction orthogonal to the sheet discharging direction, and at least one of the divided stacking members is independent of the other. And a lifting / lowering drive means for vertically lifting / lowering. A second aspect of the present invention is characterized in that, in the first aspect, the elevation driving means individually drives the divided stacking members up and down. According to a third aspect of the present invention, in the second aspect, the position detecting means for detecting the position of the upper surface of the sheet stacked on each of the divided stacking members is distributed and arranged at positions corresponding to the respective divided stacking members. It is characterized by the following. According to a fourth aspect of the present invention, in the third aspect, the position detecting means detects a position of an upper surface of the sheet on one of the divided stacking members, and
It is characterized in that the lifting drive means is controlled to drive the one divided stacking member up and down. . According to a fifth aspect of the present invention, in any one of the first, second, third, and fourth aspects, the apparatus further comprises height detecting means for detecting a step between the plurality of divided stacking members. According to a sixth aspect of the present invention, in the fifth aspect, the height detecting unit includes a warning unit that issues a warning when detecting that a step between the divided stacking members is equal to or greater than a predetermined limit distance. It is characterized by. According to a seventh aspect of the present invention, in the fifth or sixth aspect, after the height detecting means detects that the step between the divided stacking members has reached the limit distance, the elevation drive means performs all the divisions. The invention according to claim 8, wherein the loading members are simultaneously lowered, the height detecting means detects that the step between the divided loading members has reached the limit distance in claim 5, 6, or 7. After the time, the sheet discharging operation by the discharging means is stopped. According to a ninth aspect of the present invention, in accordance with the first, second, third, or fourth aspect, after the one of the divided loading members descends and the step between the other divided loading member reaches the limit distance, A forced lowering mechanism for forcibly lowering the other divided stacking member in conjunction with the lowering of one of the divided stacked members while maintaining the limit distance.

[0009] The invention of claim 10 is the invention of claim 3, 4 or 1.
0, the position detecting means detects the positions of a plurality of upper surfaces along the width direction of the trailing edge of the sheets stacked on the divided stacking member. According to an eleventh aspect, in the third, fourth, or tenth aspect, the position detecting means is configured to be movable along a width direction of a trailing edge of a sheet stacked on the divided stacking member. It is characterized by. According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, there are provided post-processing means for performing post-processing of the sheet, and discharge means for discharging the sheet post-processed by the post-processing means to the sheet stacking means. It is characterized by the following. According to a thirteenth aspect, in the twelfth aspect, the post-processing unit is a binding unit that performs a binding process on a sheet. According to a fourteenth aspect of the present invention, in accordance with the thirteenth aspect, in accordance with the binding position and the number of bindings by the binding means,
The lifting drive unit is controlled so as to select and lower an optimal divided stacking member. The invention according to claim 15 is characterized in that, in claim 13 or 14, after the number of times of binding by the binding means reaches a predetermined number, the divided stacking member corresponding to the binding position by the binding means is lowered. . According to a sixteenth aspect of the present invention, in any one of the first to eleventh aspects, an image forming unit for forming an image on a sheet, and a discharging unit for discharging the sheet to the sheet stacking unit are provided.

[0010]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of an example of a sheet stacking apparatus according to an embodiment of the present invention. The sheet stacking apparatus 1 includes an image forming apparatus 50 and a sheet stacking unit 2. The image forming apparatus 50 forms an image on the sheet (p) while forming (transferring and fixing) the toner image on the sheet (p), and a sheet stacking unit on the sheet (p) on which the toner image has been formed. Discharging means 5 for discharging to 2
2 and a discharge port 52a and a discharge roller pair 52b constituting the discharge means 52. A sheet stacking unit 2 is provided on a side surface of the image forming apparatus provided with the discharge port 52a. The image forming means 51 forms a toner image on a sheet (p) based on image recording information.
a, a scanner unit 51b for reading a document image of a document (O), and an image signal as a document image output as a digital signal from the scanner unit 51b is electrically processed, and the image recording information is transmitted to the printer main unit 51a. And an output image recording processing unit 51c. The printer main body 51a
A photosensitive member in the form of a drum as an image bearing member 51a ₁ rotatably supporting has been rotated in the arrow C direction shown, a charging section 51a ₂ for uniformly charging the image bearing member 51a _1, charging means 51a ₂ Image carrier 51a ₁ uniformly charged by
The exposure means 51a ₃ for forming an electrostatic latent image by exposing and then visualized by developing the electrostatic latent image and the developing means 51a ₄ for forming a toner image, by the paper feed roller 51a _51, for example, 2 one of the registration roller 5 sheets (p) supplied from either of the sheet feeding cassettes 51a ₆ and the paper feed cassette 51a ₇
Align the tip by 1a _8, a paper feeding means 51a ₅ for sending to the feed direction downstream side of the sheet timed,
The toner image formed on the image bearing member 51a _1, a transfer roller as a transfer means 51a ₉ for transferring the sheet (p) sent from the sheet feeding means 51a _5, the toner image has been transferred by the transfer means 51a ₉ and fixing means 51a ₁₀ which heats the sheet (p) for fixing the toner image, and the conveyance guide means 51a ₁₁ for guiding the conveyance of the sheet (p) discharged from the fixing unit 51a _10, conveyed by the conveying guide unit 51a ₁₁ Discharging means 52 for discharging the guided sheet (p) from the discharge port 52a to the outside. Further, the printer body 5
1a is provided with a cleaning blade as cleaning means 51a _12, and this by the cleaning means 51a ₁₂ the toner images scrapes residual toner remaining on the image bearing member 51a ₁ upper surface after transferring on the sheet (p) removal For the next image forming step. Scanner unit 51b
It includes a fluorescent lamp as a lamp 51b ₂ for scanning irradiation the original on the original stacking table 51b ₁ (O), a mirror group 51b are sequentially reflects the reflected light from the original (O) ₃ (mirror 51
b ₃₁ , 51b ₃₂ , 51b ₃₃ ) and an imaging lens 51b ₄ for receiving the light reflected by the mirror group. Image light incident on the light receiver 51b _5, for example, a CCD through the imaging lens 51b ₄ is incident on the image recording processing unit 51c on which is converted into a digital signal. Image recording processing section 51c is subjected to a necessary processing on the digital signal, into a signal for an image recording is formed, this signal is stored write the image information storage unit 51a ₁₃ as image information. The image information is temporarily written and saved in the image information storage unit 51a ₁₃ is output again, and sent is input to the printer main body portion 51a and the exposure means 51a _3.

Next, the sheet stacking means 2 includes a discharging means 52
And a stacking member 3 serving as a sheet discharge tray for receiving and stacking the sheets discharged from the discharge port 52a. Is divided into two in the width direction orthogonal to the sheet discharge direction A. That is, the loading member 3 comprises a first divided stacking member 3a ₁ and the second divided stacking member 3a ₂ Prefecture, are vertically movable structure at least one of the divided stacking member 3a _1, 3a _2. For this reason, the height position of at least one of the divided loading members can be changed with respect to the height position of the other divided loading member. That is, both divided stacking members may be configured to be individually movable up and down, or one may be fixed and the other configured to be movable up and down. The stacking member 3 does not necessarily need to be divided into two, and may be divided into three or more. Further, when the loading member 3 is divided into a plurality of parts as described above, it is not necessary to configure all the divided loading members so as to be able to be driven up and down independently. One of the divided loading members is fixed, and the other divided loading members are fixed. However, in the present embodiment, a description will be given mainly of a case where the two divided stacking members are configured to be able to move up and down. As a result, from the initial state (the step-less state) in which the positions of the loading surfaces (m) of the two divided loading members 3a ₁ and 3a ₂ are at the same level, one is relatively lowered with respect to the other in the direction of arrow B. (Stepped state). The reason why the two divided stacking members 3a ₁ and 3a ₂ are configured to be relatively vertically movable in the present invention is that, as will be described in detail later, in the initial state where both stacking surfaces (m) are stepless. In the case where a part (one end in the width direction of the sheet) stacked over the two divided stacking members 3a ₁ and 3a ₂ largely protrudes above the uppermost surface of the sheet due to deformation such as curl. ,
The divided stacking member 3a at one end in the width direction where the protrusion is located
_{This is for} lowering only ₁ by the required distance and flattening the uppermost surface of the sheet as a whole. By lowering the divided stacking member corresponding to the position of the protrusion in this manner, the protrusion interferes with and closes the discharge port 52a, thereby preventing a situation in which a discharge failure, a jam, and other transport troubles occur. Can be. In addition, an inclined surface around a protruding portion (thick portion) locally and cumulatively formed on the stacked sheet bundle due to deformation of each sheet deteriorates the seating stability of the sheet discharged and stacked later. In addition, it is possible to prevent stacking defects such as collapse of stacked sheets.

FIG. 2 is an explanatory view of the overall structure of a sheet stacking apparatus 1 according to another embodiment of the present invention. The sheet stacking apparatus 1 includes an image forming apparatus 50 and a sheet post-processing apparatus 1.
0 and the sheet stacking means 2 or the combination of the sheet post-processing device 10 and the sheet stacking means 2. The sheet stacking apparatus 1 has a configuration in which the sheet stacking unit 2 is assembled to a sheet post-processing apparatus 10 that receives a sheet discharged from the discharging unit 52 of the image forming apparatus 50 and performs post-processing. Image forming apparatus 50
Is almost the same as that of FIG. Further, the configuration of the sheet stacking means 2 according to this embodiment is substantially the same as that shown in FIG. 1, and the portions having the same functions as those in FIG. The point that the sheet stacking unit 2 according to this embodiment is different from that of FIG. 1 is that the sheet stacking unit 2 is attached not to the image forming apparatus 50 but to the sheet post-processing apparatus 10. The sheet post-processing apparatus 10 includes an image forming apparatus 50.
The image-formed sheets (p) discharged from the discharge means 52 are discharged by the discharge means 12 one by one or as a stapled bundle. The discharge means 12 has a discharge port 12a and a discharge roller pair 12b. The sheet post-processing apparatus 10 may perform clipping, punching, cutting, and the like, in addition to stapling, and the form, position, and protrusion amount of the bulge formed in the processing unit according to each processing. However, this embodiment mainly describes a case where stapling is performed. The stacking member 3 is composed of first and second divided stacking members 3a ₁ and 3a ₂ divided into two in a width direction orthogonal to the sheet discharge direction A, and the divided stacking members 3a ₁ and 3a ₂ are individually movable up and down. It is configured. FIG. 3 is a partial sectional view showing a schematic configuration of the sheet stacking apparatus shown in FIG.
Is a staple tray 15 on which image-formed sheets (p) discharged one by one from the discharge means 52 of the image forming apparatus 50 and received from the receiving port 10A are aligned and stacked.
A binding means 11a serving as a post-processing means 11 for stapling a sheet bundle stacked on a staple tray 15 at a required position, and a discharging means for holding the lower edge of the sheet bundle (P) bound by the binding means 11a And a belt 17 having a claw 17a for carrying the sheet upward toward the sheet 12.
This sheet bundle (P) is discharged from a discharge port 12a of the discharge unit 12 by a discharge roller pair 12b.
Is discharged. Since the sheet bundle (P) is stapled in at least one place, the local portion is thickened by the amount of the staples. When a large number of the sheet bundles (P) are stacked on the stacking member 3, the sheet portion in which the thick portion is accumulated protrudes above the other portions to close the discharge port 12a or obstruct the subsequent discharge. Or cause a stacking failure as described above. Another path 18 in the sheet post-processing apparatus 10 is a path for directly discharging the sheet discharged from the image forming apparatus 50 and received from the receiving port 10A to the outside of the apparatus from the discharge port 12a without stapling. . The sheets discharged from the path 18 to the sheet stacking means 2 are one by one. If a deformed portion such as a curl, a fold, a wrinkle, or the like is formed in a specific portion of the sheet, the sheets are discharged onto the stacking member 3. When stacked, an excessively thick portion is formed due to the accumulation of the deformed portions, causing the same problem as described above. Therefore, also in the sheet stacking means 2 of this embodiment, the stacking member 3 is composed of the first and second divided stacking members 3a ₁ and 3a ₂ similarly to the above-described embodiment, and both divided stacking members 3a ₁ and 3a ₂ are formed. It is configured to be able to move up and down individually.

Next, the detailed configuration and operation of the sheet stacking apparatus according to the present embodiment will be described in detail with reference to FIGS. First, FIG. 4 is a perspective view showing a state in which the sheet stacking means 2 according to the present invention is assembled to the sheet post-processing apparatus 10, and the sheet stacking means 2 is provided along the rear end fence of the sheet post-processing apparatus 10. Lift guide 20
And the divided loading members 3a ₁ and 3a ₂ individually and vertically movably supported by the lifting / lowering guide 20, and the divided loading members 3a
_{It has} a lifting drive mechanism 21 for individually lifting and lowering ₁ and 3a ₂ , and a position detecting means 5. Each divided loading member 3a ₁ , 3a ₂
Are provided with rack-equipped brackets 3b ₁ and 3b ₂ that extend integrally downward from the widthwise outer ends. Rack gears 3b ₁ ', 3b ₂ ' integrated with each bracket 3b ₁ , 3b ₂
, Each motor 4a constituting the elevating drive means 4, is driven up and down the forward and reverse driving force from 4b is transmitted through the pinion gear 3c _1, 3c _2. As the motors 4a and 4b, for example, motors that can rotate forward and backward are preferable, and if a stepping motor is used, it is possible to perform a control for precisely finely adjusting the distance by which each divided stacking member is moved up and down. Reference numeral 3d denotes stoppers protruding from both upper and lower wall surfaces of the ascending and descending movement paths of the brackets 3b ₁ and 3b ₂ with racks.
When the upper end or lower end of b ₁ or 3b ₂ abuts against each stopper 3d, further ascent or descent is prohibited.

In the state shown in FIG. 4, both divided loading members 3a ₁ ,
3a ₂ of the stacking surface (m) is located at the same level (no step condition), the height position of the two half stacking member in this case is the outlet port 12
The position is set to a position suitable for stacking the sheets discharged from a. The position detecting means 5 (5a ₁ , 5a ₂ ) will be described in detail later. The position detecting means 5 is composed of a plurality of contact sensors or non-contact sensors, and the position of the uppermost surface of the sheet on the stacking member 3, particularly the protrusion ( E) If there is, any of the position detecting means is installed at the same height position so as to have a function of detecting this first. 5 shows a state of being lowered only one divided stacking member 3a ₂ from non-step state of FIG. 4, both split stacking member 3a in a non-step state shown in FIG. 4
_1, the divided stacking member 3a ₂ side 3a ₂ sheets discharged and stacked across (p) or staple, detecting the protrusion when the protrusion due to the deformation habit of curling or the like is formed second divided stacking member 3a ₂ by a predetermined distance downward, the first divided stacking member control means (not shown) based on the detection signal from the position detecting means 5a ₂ is located on the projecting portion side by driving the lift driving means 4b forming a step D between the 3a _1. Then, since the projecting portion again by newly stacked sheets is formed is continued loading, so that the lowering long protrusion amount corresponding second divided stacking member 3a ₂ of the protruding portion. As described below, in order to prevent the collapse is seated balance of stacked sheets by increasing the step, the descent distance of the second divided stacking member 3a ₂ (level difference) is set in advance limits, step size limits When the loading is continued after reaching the above, the divided loading members 3a ₁ and 3a ₂ are lowered synchronously while maintaining the step size.

FIG. 6 is a diagram showing the operation of both divided stacking members when stacking the stapled sheet bundle (P) on the stacking member 3. The binding process by the binding means 11a shown in FIG. The first and second divided stacking members 3 that have received the sheet bundle (P) are in a state of no step from the discharge port 12a.
When the staples (S) overlap with each other when they are discharged over and stacked on a ₁ and 3a ₂ , the portions become thicker,
As shown by the broken line, a protrusion (E) is formed on the upper surface near one end. Further, an inclined surface (E ′) having a slope having the protrusion (E) as a vertex is also formed continuously. In the present embodiment, the second divided stacking member 3 on the side where the protruding portion (E) is located
a ₂ is lowered in the direction of arrow F, and the first divided stacking member 3a ₁
By forming a step D between the _first and second divided loading members 3a2, the protruding portion (E) and the inclined surface (E ') are eliminated,
The uppermost surface of the sheet is almost flat. Therefore, the protruding portion (E) protruded by the staple needle (S)
Does not interfere with the discharge port 12a, and the inclined surface (E ') does not cause the stacking collapse of the sheet bundle (P). next,
FIG. 7 is a diagram illustrating the operation of the divided stacking member when stacking sheets having deformed portions such as curl and kinks on the stacking member 3, and illustrates a sheet discharged one by one from the image forming apparatus 50. The sheets discharged one by one via the path 18 of the sheet post-processing apparatus shown in FIG. 3 are fed from the discharge port 52a to the first and second divided stacking members 3a ₁ , 3a ₂ in a stepless state.
When the sheets are stacked on top of each other, the deformed portions of the sheets overlap with each other and the portions become thicker, and a protruding portion (E) and an inclined surface (E ′) are formed on the uppermost surface thereof as shown by a broken line. .
In this embodiment, the projecting portion (E) is the second divided stacking member 3a ₂ on the side located is lowered in the direction of arrow F, between the first divided stacking member 3a ₁ and the second divided stacking member 3a ₂ By forming the step D, the protrusion (E) and the inclined surface (E ')
And the uppermost surface of the sheet is made almost flat. For this reason, the protruding portion (E) thickened by the accumulation of the deformed portions interferes with the discharge port 52a, or the inclined surface (E ′)
Does not cause stacking collapse of the sheet bundle (P). If the step D is excessively enlarged, the balance of the sheets stacked on both divided stacking members is lost, and the sheet is displaced or dropped toward the lower divided stacking member. Need to set a limit, which will be described later.

FIG. 8 shows a sheet according to another embodiment of the present invention.
FIG. 2 is a configuration diagram of a stacking device, and illustrates discharge of a sheet post-processing device 10.
A contact-type position detecting means 5 is provided on the wall surface just below the mouth 12a.
5a with first filler as sensor₁And the second filler
With sensor 5a_TwoAre arranged at the same height. Each file
Sensor 5a₁, 5a_TwoIs the first divided loading member 3a
₁And the second divided loading member 3a_TwoAre located at positions corresponding to
It is. Sensor 5a with first filler₁With 2nd filler
Sensor 5a_TwoIs the first divided loading member 3a₁And the second split product
Mounting member 3a_TwoOf the part loaded over
The height of the upper surface of (p) is set along the width direction of the sheet.
Position on both split loading members
Individually detects the protrusions formed on the sheet part located at
I can do it. In addition, sensor with filler
Is a contact detection protruding on the upper surface, for example, near the trailing edge of the sheet.
When the means is pushed up more than a predetermined distance by the upper surface
Then, an electrical or optical switch is provided by the contact detecting means.
It is activated by turning on the switch. This
In the embodiment, the two position detecting means 5 are connected to the outlet 12a.
An example was shown in the vicinity of both ends in the longitudinal direction.
This is only an example.
It is. For example, in the width direction of sheets to be discharged and stacked
Multiple pairs of position detection means to respond to changes in
May be placed. However, if at least two position detection sensors are
If it is arranged corresponding to the inside position of both ends in the width direction of the
Light is established, and it is not necessary to provide a sensor at the center in the width direction.
Not as a rule. For example, the trailing edge of the stacked sheets
If it is protruding as a body,
Can detect this at the same time.
There is no problem of interference with the outlet 12a. Follow
In this case, lower the two divided loading members at the same time.
That would be good. However, the staple position and deformation
In relation to the position, for example, the central part in the width direction of the trailing edge of the stacked sheet
If only the sensor protrudes, install a sensor at the center as well.
We need to be able to detect this. Therefore, loaded
Prediction of where the protruding part is formed on the rear edge of the sheet
If this is not possible, use three or more sensors in the sheet width direction.
Along or move the sensor as described below
It is preferable to make it possible.

FIG. 9 is a view for explaining the operation of the embodiment shown in FIG. 8. In FIG. 9A, a sheet bundle (P) having undergone binding processing at one corner of the rear edge in the sheet discharging direction is shown. , Are sequentially discharged and stacked on the first and second divided stacking members 3a ₁ and 3a _{2 in the} stepless state. At this time, although the staples (S) of each sheet bundle overlap each other, the accumulated amount of protrusion is small because the number of sheets in the sheet bundle (P) is small, and the top surface of the sheet bundle is nearly flat and large. The portion (E) and the steeply inclined surface (E ′) are not formed. Therefore, none of the position detecting means 5 detects the sheet bundle (P). Next, in FIG. 9B, FIG. 9A shows the number of stacked sheets of the sheet bundle (P) stacked over the first and second divided stacking members 3a ₁ and 3a _{2 in the} stepless state.
, The amount of protrusion of the upper surface of the sheet accumulated due to the overlap of the staples (S) becomes large, and the large protrusion (E) and the inclined surface (E) having a large inclination angle on the uppermost surface. ') Is formed. Therefore, the protruding portion corresponding to the top of the inclined surface (E ') (E) is greater protrudes than the uppermost surface of the sheets stacked on the first divided stacking member 3a _1, detected by the position detecting means 5a ₂ It has been done. When this state is left, the protruding portion (E) prevents the sheet from being discharged from the discharge port 12a, and the inclined surface (E ') is displaced in the inclined direction and drops.
Therefore, in FIG. 9C, the sensor 5a with the second filler is used.
_{On the} basis of the detection signal from ₂ , the control means 7 drives the second motor 4b constituting the elevation drive means 4 to rotate in the downward direction. And at least the sensor 5a with the second filler
Until ₂ is in the non-detection state, only the preset number of revolutions,
By rotating the second motor 4b to lowering direction is stopped by the second divided stacking member 3a ₂ by a predetermined distance lowered in the arrow F direction. For this reason, the uppermost surface of the sheet (p) is almost flat, and a protruding portion (E) is formed which is small enough to leave a loosely inclined surface (E '). If the discharge and stacking of the sheets continue after this, a new stacking state having the protruding portion (E) and the inclined surface (E ′) on the uppermost surface of the flattened stacked sheet is generated again. Sensor 5 with second filler
When a ₂ again detects the protrusion, the second motor 4b
Is driven in the descending direction. When both the sensors with fillers 5a ₂ and 5a ₁ detect the protruding portion, both the divided laminated members 3a ₁ and 3a ₂ are lowered by a predetermined amount. The descending amount at this time is set to be larger than the descending amount when only one of them is lowered. As a result of sequentially repeating this lowering operation, if the step between the two divided stacking members becomes excessively large, a misalignment or drop occurs in the sheet due to improper stacking. Therefore, it is necessary to maintain the value of the step within a certain value. The height detecting means 6 shown in FIGS. 8 and 9 is a means for determining the limit of the range of enlargement of the step.

That is, the height detecting means 6 is
Warning means 6a operated by the control signal of
With bracket 3b₁From the right place inside the
Bracket 3b_TwoThe tip protruding toward is U-shaped
A first height detection arm 6b having a shape and a tip of the first height detection arm 6b
U-shaped detector 6b located at the end₁The first provided at the upper end of the
Height sensor 6b_TwoAnd the U-shaped detector 6b₁At the bottom of
Second height sensor 6b _ThreeAnd a bracket with a second rack
3b_TwoU-shaped detector 6b from the right place inside₁Both heights
Sensor 6b_Two, 6b_ThreeThe second integrated to protrude between
And a height detection arm 6c. Thus, for example,
1st bracket 3b with a rack ₁Second to
Bracket 3b with rack_TwoCan move up and down
Condition detection unit 6b₁The distance between the upper and lower ends, ie, both height sensors
6b_Two, 6b_ThreeIs limited to the interval between. That is, the second height
The detection arm 6c cannot move up and down beyond the position of the sensor.
And is integrated with the second height detection arm 6c.
Bracket 3b with 2nd rack_TwoCan move up and down
Regulated to the same extent. First height sensor 6b_TwoWhen,
Second height sensor 6b_ThreeIs the contact or proximity of the detection arm 6c
What kind of detection means can detect
For example, a limit switch or the like is used. Also,
As shown in FIGS. 9A and 9B, both divided loading members 3
a₁, 3a_TwoIs in the stepless state, as shown in FIG.
The detected arm 6c is located at an intermediate position indicated by a chain line, that is, an upper and lower position.
Sensor 6b_Two, 6b_ThreeIn the middle position of
From the second height detection arm 6c to each height sensor 6b_Two, 6b_ThreeMa
(X) is two divided loading members 3a₁, 3a_Twowhile
Is set to be the limit value of the step D formed in
You. In other words, both divided loading members 3a₁, 3a_TwoStep between
If D is within the range of the distance (X), it is caused by the existence of the step D
There is no danger that a stacking defect will occur, and the step D
If (X) is exceeded, the loading failure due to the existence of the step D
This means that there is a high possibility that goodness occurs. In the present invention
Means that the step D exceeds the distance (X) by the height detecting means 6.
Is controlled so that it does not increase due to poor loading.
The shift and drop of the sheet can be prevented.

Next, when performing control to the second divided stacking member 3a ₂ whenever the second filler with sensor 5a ₂ detects the projecting portion as shown in FIG. 9 (c) by a predetermined distance at a time lowered, the Although the control means 7 as long as the second height sensing arm 6c does not reach the lower level sensor 6b ₃ continues to rotate the second motor 4b to lowering direction, the height sensor of the second height detection arm 6c is lower when reaching 6b _3, the control unit 7 height sensor 6
Based on the detection signal from the b ₃ a warning sound or warning by an alarm means 6a, and the driving start the first motor 4a in synchronism with the second motor 4b, which continues to drive the downward direction to the downward direction Let it. Alternatively, the control unit 7, the second when the second height detection arm 6c has reached the height sensor 6b ₃ of the lower
The driving of the motor 4b is stopped to issue a warning, and further, the sheet discharging operation is prohibited. After that, when the discharge is continuously performed, the control unit 7 starts driving the first motor 4a in the descending direction, and maintains the step D so that the two divided stacking members 3 are maintained.
a ₁ and 3a ₂ are lowered synchronously. The control unit 7 is usually provided in the sheet post-processing apparatus 10 or the image forming apparatus 50, and the like.
Alternatively, it is incorporated in the image forming apparatus 50 in an electrically and mechanically close relationship. Figure 10 is a schematic diagram showing the operation of each part when lowering the first divided stacking member 3a ₁ contrary to the example shown in FIG. 9, the sheet bundle discharged from the discharge port 12a of the sheet post-processing device ( In P), a binding process is performed on the end opposite to that in FIG. In this example,
Since the first _1-side filler with the sensor 5a is binding position, the protrusion portion stacking amount of sheets across the first and second divided stacking member 3a _1, 3a ₂ on corresponds to the binding position increases when (E) is formed, the first filler with sensor 5a ₁ detects the projecting portion ahead. Control means 7, based on the detection signal from the first filler with sensor 5a _1, forming a step D the first motor 4a between both divided stacking member is rotated by the downward direction by a predetermined rotational speed.
Then, after confirming that the _first sensor with filler 5a1 is not detected, the first motor 4a is stopped. When the first and second divided stacking members 3a ₁ , 3a ₂ are in a stepless state, the upper and lower height sensors 6b ₂ , 6b ₂ provided on the U-shaped detector 6b ₁ integrated with the first rack-mounted bracket 3b ₁ second height sensing arm 6c at an intermediate position 6b ₃ so is located, is arranged in the initial position shown co shape detection unit 6b ₁ by a chain line. On the other hand, the first divided loading member 3a
_When only ₁ is lowered, the U-shaped detector 6b ₁
Upper height sensor 6b ₂ as shown by the solid line to the descent of the relative height detection arm 6c is slide into close to the second height detection arm 6c. When the first filler with sensor 5a ₁ performs control to first split the carrying member 3a ₁ descent predetermined distance at a time every time of detecting the projecting portion of the stacked sheets, the upper height sensor 6b ₂ is the second height The control means 7 rotates the first motor 4a intermittently in the descending direction until the detection arm 6c is detected, but the upper height sensor 6b ₂ detects the second height detection arm 6c.
When detecting a, the control unit 7 stops the driving of the first motor 4a based on the detection signal from the height sensor 6b _2, or a warning sound by a warning means 6a,
Perform warning display. After that, when the discharge is continuously performed, the control unit 7 starts driving the second motor 4b in the descending direction, and maintains the step D so that the two divided stacking members 3
a ₁ and 3a ₂ are lowered synchronously.

FIG. 11 is a flowchart showing the operation of the sheet stacking apparatus according to each embodiment shown in FIGS. 1 to 10. The operation and control procedure common to each of the above embodiments will be described based on this flowchart. . First, in step 1, the sheet subjected to the image forming process by the image forming unit 51 in the image forming apparatus 50 shown in FIG. 1 or the binding process by the binding unit 11a in the sheet post-processing device 10 shown in FIG. The received sheet bundle is delivered to each of the discharging means 52, 12
Is discharged onto the stacking member 3 of the sheet stacking means 2 and stacked. In step 2, it is determined whether or not both the first and second sensors with fillers 5a ₁ and 5a ₂ are turned on.
If N, the first and second motors 4a,
4b are turned on to start lowering the two divided stacking members 3a ₁ and 3a ₂ simultaneously. In step 4, it is determined whether or not the first and second motors 4a and 4b have been driven by a predetermined amount. If the first and second motors 4a and 4b have been driven by a predetermined amount, both motors are turned off to stop the lowering of both divided stacking members (step 5). In step 6, the presence or absence of the next sheet or the next sheet bundle is determined, and if there is, the process returns to step 1. Subsequently, when Step 2 is No,
In step 7 only the first filler with sensor 5a ₁ is determined by the presence or absence of the detection signal whether the detected uppermost surface (the protruding portion (E)) of the stacked sheets, from the first filler with sensor 5a ₁ If there is a detection signal (step 7
Yes), the process proceeds to a step S8, in which the first motor 4a is started to rotate in the descending direction.
(C) the height detection unit shown 6 value of the step D between the (second height detection arm 6c and height sensor 6b ₂₎ first divided stacking member 3a ₁ by a second divided stacking member 3a ₂ Is determined to have reached a limit distance (X) as a limit value of the step,
If the limit distance (X) has been reached (No in step 9), the process proceeds to step 10, in which the lowering drive of the second motor b is started. 4b at the same time starts rotating in the downward direction at a constant speed. At the same time, the warning means 6a notifies that the value of the step D has reached the limit distance (X) by a warning sound or a warning display. In the following step 11, it is detected whether or not the _first sensor with filler 5a1 is OFF. If it is OFF, the driving of the first and second motors 4a and 4b is stopped (step 12). Further, in step 23, the presence or absence of the next sheet or sheet bundle is determined, and if there is, the process returns to step 1. The first filler with sensor 5a ₁ is OF step 13 if the value of the step D in step 9 the contrary is not detected that reaches the limit distance (X)
F, and if it is OFF, the first motor 4
a is turned off. The details of the determination in step 23 are the same as described above.

Next, if in step 7 the first filler with sensor 5a ₁ does not output the detection signal, that is, the projecting portion of the sheet on the stacking member 3 (E) is not detected, the process proceeds to step 15, determining the presence or absence of the second detection signal of the filler sensor with 5a _2. That is, the second divided loading member 3
a sheet protruding portion located on ₂ (E), only the second filler with sensor 5a ₂ determines whether the detected. If step 15 is No, that is, if there is no detection signal, the process proceeds to step 23. If there is a next job in step 23, the process returns to step 1, and if there is no next job, the process ends. Also, when step 15 is Yes, the words when the second filler with sensor 5a ₂ detects protrusions sheet on the second divided stacking member 3a ₂ of (E), the process proceeds to step 16, a second motor 4b Is started in the descending direction. In step 17, the second height detection means 6 (second height detection arm 6c and height sensor 6b ₃ )
The value of the step D between the divided stacking member 3a ₂ and the first divided stacking member 3a ₁ may determine whether it has reached the limit distance (X) as a limit value of the step, the limit distance (X) If it has reached, the process proceeds to step 18, in which the driving of the second motor 4b in the descending direction is started, and the first and second motors 4a and 4b are simultaneously driven to rotate in the descending direction at the same speed. At the same time, the warning means 6a notifies that the value of the step D has reached the limit distance (X) by a warning sound or a warning display. In the following step 19, the sensor 5a ₂ with the second filler is
It is determined whether or not the motor is FF. If the motor is OFF, the first and second motors 4a, 4b
To OFF. On the other hand, step D
Is not detected to have reached the limit distance (X), it is determined in step 21 whether or not the _second sensor with filler 5a2 is OFF.
Stop b. In step 23, if there is no next sheet or sheet bundle, the flow is ended. However, if there is another sheet or sheet bundle, the flow returns to step 1. The control means 7 performs control in accordance with the above procedure based on the detection signals from the divided position detection sensors, so that the discharge ports 52a, 52 of the image forming apparatus or the sheet post-processing apparatus, etc.
a, even if the protruding portion (E) is formed on the sheet (p) discharged in large quantities and stacked on the stacking member 3, any one of the divided portions is almost equal to the protruding portion (E). Since the stacking member is lowered, the uppermost surface of the rear end portion of the sheet can be substantially flattened, thereby preventing blockage of the discharge port, jam due to poor discharge, and misalignment or collapse due to poor stacking. it can.

Next, FIG. 12 relates to another embodiment of the present invention.
FIG. 8 is a diagram for explaining a configuration of a sheet stacking apparatus according to the first embodiment.
9 is a modification of the embodiment described with reference to FIG.
You. That is, in the embodiment shown in FIG.
In the state where both the divided loading members 3a ₁, 3a_TwoDescend synchronously
At this time, the first and second motors 4a and 4b are respectively synchronized.
In this embodiment, the forced
By using the lowering mechanism 20, one motor is driven.
When lowering one of the divided stacking members
The feature is that the loading member is forcibly lowered.
is there. The forced lowering mechanism 20 includes the first bracket 3 with a rack.
b₁Bracket 2b with second rack from the right place_TwoRush towards
The first engagement arm 20a provided and the second bracket 3 with a rack
b_Two1st bracket 3b with rack from the right place₁Rush towards
And a second engagement arm 20b provided. First engagement arm 20
a has a U-shape at the tip, and the U-shape is the upper arm 20a-.
1 and the lower arm 20a-2. The first engagement arm 20a
In a state of protruding between the upper and lower arms 20a-1 and 20a-1
is there. That is, the second divided loading member 3a located on the lower side_Twofor
Drive only the second motor 4b in the descending direction, and
20b is engaged with the lower arm 20a-2 of the first engagement arm 20a.
The first divided stacking member 3a₁To
It can be forcibly lowered simultaneously. Conversely, the first
Split loading member 3a₁Is located on the lower side, the first
The upper arm 20a-1 of the arm 20a is engaged with the second engagement arm 20b.
The second divided stacking member 3a
_TwoAre forcibly lowered simultaneously. In this case, stop driving
State of the first motor 4a or the second motor 4b
Connected pinion gear 3c₁Or 3c_TwoEtc. on the shaft
A limiter or the like is provided to apply an unreasonable load to the first motor 4a.
Be careful not to be confused. Note that the embodiment of FIG.
Therefore, the same parts as those shown in FIGS.
The same reference numerals are given and the description of the duplicated configuration is omitted.
However, the embodiment of FIG. 12 is the embodiment shown in FIGS.
The main difference between the first and second height detecting arms 6b and 6c
That first and second engagement arms 20a and 20b are provided in place of
And the vertical height sensor 6b_Two, 6b_ThreeDoes not exist,
One split loading member mechanically connects the other split loading member
This is the point of the control procedure for forcibly descending. Next
FIG. 13 shows a sheet stacking operation according to the embodiment shown in FIG.
5 is a flowchart showing the operation of the apparatus,
Explanation of the operation and control procedure according to this embodiment based on the
I do.

First, in step 30, the sheet subjected to image forming processing by the image forming means 51 in the image forming apparatus 50 shown in FIG. 1 or the binding means 11a in the sheet post-processing apparatus 10 shown in FIG. The sheet bundle subjected to the binding processing or the like is sequentially discharged from each of the discharge units 52 and 12 onto the stacking member 3 of the sheet stacking unit 2 and stacked. Step 3
In step 1, it is determined whether the first and second sensors with fillers 5a ₁ and 5a ₂ are both turned on. If both are turned on, the first and second motors 4a and 4b are turned on in step 32.
Thus, the two divided loading members 3a ₁ and 3a ₂ are simultaneously started to descend. In step 33, it is determined whether or not the first and second motors 4a and 4b have been driven by a predetermined amount. . In step 35, the presence or absence of the next sheet or the next sheet bundle is determined, and if there is, the process returns to step 30. Subsequently, when Step 31 is No,
In step 36 only the first filler with sensor 5a ₁ is determined by the presence or absence of the detection signal whether the detected uppermost surface (the protruding portion (E)) of the stacked sheets, from the first filler with sensor 5a ₁ If there is a detection signal (step 3
6 Yes), the process proceeds to step 37, the first motor 4a rotational drive begins to lowering direction, continues in step 38 the first filler with sensor 5a ₁ it is determined whether the OFF, projection when OFF (E) is discharge means 5
This means that the first and second motors 2 and 12 have stopped interfering with each other. In the subsequent step 44, if there is a next job, the process returns to step 30, and if there is no next job, the process ends. Next, while sequentially repeating an operation to lower the first division stacking member 3a _1, the value of the step D between the both split stacking member 3a _1, 3a ₂ reaches the limit distance (X) as a limit value of the step However, in this embodiment, as shown in FIG. 12, the U-shaped first height detection arm 20a and the second height detection arm 20b function as means for mechanically forcing the other down. It is not necessary to provide a means for detecting whether or not the limit distance (X) has been reached as in the embodiment shown in FIG.

Next, when step 36 is No, the first filler with sensor 5a ₁ to That first filler with sensor 5a ₁ does not detect the uppermost surface of the stacked sheets (protrusion (E)) If there is no detection signal at step 40, only the sensor 5a ₂ with the second filler
It is determined whether N has been performed. Sensor 5a with second filler
_If only ₂ is turned on, the process proceeds to step 41, in which the second motor 4b is started to be driven to rotate in the downward direction.
In step 2, it is determined whether or not the _second sensor with filler 5a2 is turned off. If the sensor is turned off, it means that the protruding portion (E) has stopped interfering with the discharging means 52, 12, so that in step 43 The second motor 4b is turned off.
In the subsequent step 44, if there is a next job, the process returns to step 30, and if there is no next job, the process ends. Again, while sequentially repeating an operation to lower the second divided stacking member 3a _2, the value of the step D between the both split stacking member 3a _1, 3a ₂ is a limit distance (X) as a limit value of the step However, since the U-shaped first height detection arm 20a and the second height detection arm 20b function as means for mechanically forcing the other down, as shown in the embodiment shown in FIG. It is not necessary to particularly provide a means for detecting whether or not the limit distance (X) has been reached. By using the forced lowering mechanism 20 according to this embodiment, the two divided loading members can be lowered with the simple mechanical configuration while maintaining the step D at the limit distance (X). However, it is possible to prevent problems such as the step D being enlarged and the stacked sheets being dropped.

FIG. 14 is a schematic view of a main part of a modified embodiment of the present invention. A non-contact sensor as a position detecting means 5 is provided at an appropriate position of the discharge port 12a of the sheet post-processing apparatus 10, for example, at both lower ends in the longitudinal direction of the discharge port. The configuration in which 5b is arranged is characteristic. Non-contact sensor 5b, the first optical sensor 5b ₁ and made from the second optical sensor 5b ₂ Prefecture, respectively first and second divided stacking member 3a _1, the 3a ₂ of the sheets stacked across on the loading surface It is configured so that the height of the uppermost surface can be detected. The respective optical sensors 5b _1, 5b _2, using a reflective type in combination, for example with known as light-emitting element and a light receiving element. Since the non-contact sensor 5b can detect this without contacting the upper surface of the sheet, it has an advantage that the sheet is not stained. Note that, in this embodiment, an example in which a pair of non-contact sensors, that is, two non-contact sensors is arranged is shown, but this is merely an example, and two or more pairs may be arranged. With such a configuration, when the sheets having different widths are stacked, the positions of the protruding portions (E) formed at different widthwise positions can be accurately detected by the sensor pairs having different widthwise positions. It becomes possible, and the detection accuracy is improved.

FIG. 15 is a view showing the configuration of a main part of another modified embodiment of the present invention.
For example, the first and second sensors with filler 5a ₁ ,
5a ₂ , the first and second sensors 5 with fillers
a ₁ and 5a ₂ are supported movably in the sheet width direction G by a feed screw 5c disposed below the discharge port 12a. Feed screw 5c, the longitudinal center first and second thread portion 5 different screws directions (both split stacking member 3a _1, 3a ₂ of the position corresponding to the boundary portion) as a boundary
c _1, 5c comprises _two, first and second screw portions 5c _1, 5c ₂
The first and second sensors with fillers 5a ₁ and 5a ₂
Are screwed together. The first and second sensors with filler 5a ₁ and 5a ₂ are prevented from rotating by a stopper (not shown), and maintain the posture shown in FIG. and it is movably supported equidistant increments synchronously in and out along the threaded portion 5c _1, 5c _2. A motor 5d is used as a drive source of the feed screw 5c. The configuration of the moving mechanism of the position detecting means 5 described above is suitable for a case where sheets are discharged and stacked on the basis of the center. The position detecting means located at one end in the width direction as a reference is fixed, and only the other is moved in the width direction. As the position detecting means 5 used in this embodiment, a detecting means other than the above-described sensor with a filler, for example, a non-contact sensor 5b having a configuration as shown in FIG. 14 may be used. Whatever type of detecting means is used, the position detecting means 5 is discharged from the discharge port 12a and
The uppermost surface of the sheets (p) stacked on the sheets a ₁ and 3a ₂ , particularly, the sheet (p) is arranged at a height position such that the position where the protruding portion (E) is formed can be reliably detected. Moreover, it is possible to change the width position so that accurate detection can be performed following the change in the position of the protruding portion caused by various factors such as a change in the width direction dimensions of the stacked sheets and a change in the staple position. As a result, detection accuracy can be improved. Further, since the number of the position detecting means can be reduced to a minimum of two, the mechanical configuration and the electrical control can be simplified. Note that the sheet stacking device 1 can be regarded as the sheet stacking unit 2 alone. That is, in the above-described embodiment, a combination of the image forming apparatus 50 and the sheet stacking unit 2, or a combination of the sheet post-processing apparatus 10 and the sheet stacking unit 2, or the image forming apparatus 50, the sheet post-processing apparatus 10 and the sheet stacking unit The combination with the unit 2 is the sheet stacking device 1, but the single configuration of the sheet stacking unit 2 can be considered as the sheet stacking device 1.

FIG. 16 is a perspective view showing an essential part of an example of a sheet stacking apparatus provided with a sheet post-processing apparatus.
The sheet post-processing apparatus 10 includes a post-processing unit 11 including a binding unit 11a that binds an image-formed sheet (p) received from the receiving port 10A with a staple as shown in FIGS. A discharge means 12 for discharging the sheet bundle (P) bound by the means 11a to the sheet stacking means 2; first and second fences 15a and 15b along both edges in the width direction;
A staple tray 15 having a flat shape and a moving means 13 for moving the binding means 11a in the width direction along the lower edge (rear edge) of the sheet bundle (P) stacked on the staple tray 15; Belt 1 provided with the pawl 17a
7 (FIG. 3). The discharge means 12 is, for example, the discharge port 1
2a and a discharge roller 12b. Reference numeral 19 denotes a control panel provided in the image forming apparatus 50 or the sheet post-processing apparatus 10, and is a means for an operator to input various instructions to the control means 7. Reference numeral 5 denotes position detecting means, and 6a denotes warning means. The moving means 13 includes:
A timing belt 13a which is stretched endlessly by sprockets and has binding means 11a fixed in place.
A gear group 13b for transmitting a driving force to the timing belt 13a, a guide shaft 13c serving as a guide when the binding means 11a moves in the forward and reverse directions shown by arrows, and a rotational driving force is output by meshing with the gear group 13b. And a geared motor as the driving source 13d. When the binding process is selected on the control panel 19, the control unit 7
By rotating the timing belt 3d to move the timing belt, the binding unit 11a is stopped at an arbitrary position along the rear edge (lower edge) of the sheet (p), and is operated to perform the binding process. For binding position by an input from the control panel 19 for operator in advance, before stitching (3a ₁ side), since one is selected either from one of the two binding the back stitching (3a _2), the control The means 7 can detect the binding position from the selection result. FIG. 17 is an explanatory view of the configuration of the sheet stacking means 2 applied to the sheet post-processing apparatus shown in FIG. 16, and in this example, two position detecting means 5 (5a ₁ , 5a ₂ ) arranged respectively near and behind. Instead of the loading member 3
The single position detecting means 5 is disposed at a position directly below the discharging means 12 corresponding to the central portion of the rear end edge (the boundary position between both divided stacking members). In the example of FIG. 16, since the binding position, the number of sheets to be bound, and the number of sheets in the sheet bundle are known in advance by an input operation from the control panel 19, the position of the uppermost surface of the sheets actually stacked on the stacking member 3 The position detecting means 5 is provided at one place as means for detecting the position. By arranging the position detecting means 5 at the central part in the width direction in this way, even if the height of the central part in the width direction of the stacked sheets does not interfere with the discharging means 12, the binding means will be described later. When the number of times of binding by 11a reaches a predetermined number of times (for example, five times), an operation of lowering only the divided stacking member on the binding position side by a predetermined distance becomes possible.

In the configuration examples shown in FIGS. 16 and 17, when the sheet post-processing apparatus 10 discharges the bound sheet bundle onto the stacking member 3, the binding unit is configured to perform the binding based on the number of bindings by the binding unit 11a. It is possible to control to lower the divided stacking member on the side where it is located. That is, the number of sheets to be bound in one binding process can be recognized in advance by the control means 7 by input from the control panel 19, so that when a number of sheet bundles are stacked on the stacking member 3, the projecting portion (E) is Since it is possible to calculate whether it interferes with the discharge unit 12 or causes the stacking sheet to collapse, by performing control to lower the divided stacking member when the number of bindings by the binding unit 11a reaches a predetermined number, This makes it possible to prevent defective discharge and collapse of the sheet bundle in advance. The binding position includes a front binding (first divided stacking member side), an inner binding (second divided stacking member side), a two-position binding, and the like. Can be determined by the control means 7 based on That is, FIG. 18 is a flowchart illustrating a control procedure of an embodiment in which control is performed to lower the divided stacking member on the side where the protrusion (E) is located, based on the number of times of binding. First, in step 50, a sheet or a sheet bundle is discharged from the sheet post-processing device 10 to the sheet stacking unit 2. In step 51, it is determined whether or not the position detecting means 5 arranged at a position corresponding to the center in the width direction of the loading member 3 has been turned on. If the position detecting means 5 has been turned on, in step 52, the first and second motors 4a, 4b And starts driving in the descending direction in synchronization with. At this time, when the descending distance of the first and second divided stacking members 3a ₁ and 3a _{2 in} the stepless state reaches the predetermined amount N, both motors 4a and 4b are simultaneously turned off (step 5).
3, 54). If there is a next sheet or sheet bundle, the process returns to step 50; otherwise, the process is terminated (step 5).
5). Here, the predetermined amount N means that the uppermost surface at the center in the width direction of the sheets or sheet bundles stacked over the first and second divided stacking members 3a ₁ and 3a ₂ in the stepless state is the discharge unit 12. This is a distance at which the divided stacking members are simultaneously and simultaneously lowered when reaching the height at which they interfere with each other.
This is the distance at which zero new sheets or sheet bundles can be stacked.

Next, if step 51 is No, that is, if the position detecting means 5 located at the center in the width direction is not turned on, it is determined in step 56 whether the front stapling has been continuously performed a predetermined number of times, for example, 5 copies. It is determined whether or not the front binding has been performed for five copies, and the front binding count is set to 0 in step 57.
To further the first motor 4a for driving the first divided stacking member 3a ₁ which corresponds to the front binding position starts driving the downward direction at step 58. Note that the predetermined number of copies, first, facilities binding processing when a sheet bundle receiving a front binding on a second divided stacking member 3a _1, 3a ₂ are sequentially stacked stopped at the initial position without the stepped state This indicates a stacking amount that is considered to cause the bound portion to interfere with the ejection unit 12. Next, in step 59, it is determined whether or not the value of the step D between the _first and second divided stacking members 3a ₁ and 3a ₂ has reached the limit distance (X). (Yes), the falling distance is a predetermined amount n of the first divided stacking member 3a ₁ at step 60
Is determined, and when the predetermined amount n is reached, the first motor 4a is turned off (step 61). Here, the predetermined amount n is a distance corresponding to the total thickness of the staples stapled on the five sheet bundles. That is, before reaching the limit distance (X), 5
The sheet bundle parts by a distance corresponding to the sum amount of stapled staple lowers the first divided stacking member 3a ₁ sequentially repeats the operation of stopping (Step 59 → 60
→ 59 → ・ ・ ・). If No in step 59, that is, if the value of the step D reaches the limit distance (X), the lowering of the second motor 4b is started in parallel with the driving of the first motor 4a. Warning means 6a
Is activated (step 62). Next, the first motor 4
Both motors 4a when the distance which the first divided stacking member 3a ₁ is lowered reaches a predetermined amount n by lowering driving a, 4
b is turned off (steps 63 and 64). That is, the first
After the step D between the first and second divided stacking members 3a ₁ and 3a ₂ reaches the limit distance (X), it is lowered while maintaining the limit distance (X), and the lowering amount of the first motor is reduced to the predetermined amount n. Control is performed so that the lowering of both motors 4a and 4b is stopped at the time of reaching. Next, the process proceeds to step 74, and if there is a next job, the process returns to step 50. If there is no next job, the process ends.

If it is determined in step 56 that five consecutive copies are not performed, the process proceeds to step 65. In step 65, it is determined whether or not a predetermined number of copies, for example, 5 copies, have been performed continuously, and if 5 copies have been performed, the back binding count is set to 0 in step 66.
7 a second motor 4b for driving the second divided stacking member 3a ₂ which corresponds to the inner binding position starts driving the downward direction at. In step 68, the first and second divided loading members 3
It is determined whether or not the value of the step D between a ₁ and 3a ₂ has reached the limit distance (X), and if the value does not reach the limit distance (X) (Ye
The s), falling a distance of the second divided stacking member 3a ₂ it is determined whether or not has reached a predetermined amount n at step 69, a predetermined amount n
Is reached, the second motor 4b is turned off (step 70). Here, the predetermined amount n is a distance corresponding to the total thickness of the staples when the back stapling is performed on the five bundles of sheets. If No in step 68, that is, if the value of the step D has reached the limit distance (X), the first motor 4a is started to descend and is driven to descend together with the second motor 4b. 6a is operated (step 71). Then, the motors 4a, the 4b OFF when the distance which the second divided stacking member 3a ₂ are lowered by lowering driving the second motor 4b reaches a predetermined amount n
(Steps 72 and 73).

[0031]

As described above, according to the first aspect of the present invention, the sheet stacking means includes at least two divided stacking members divided in the width direction orthogonal to the sheet discharging direction. Since at least one of them is configured to be able to move up and down independently of the other, the sheets stacked on each of the divided stacking members are caused by deformation such as stapling or curling at the width direction ends and the like. When the protrusion is formed, the uppermost surface of the sheet can be flattened by lowering the divided stacking member on the side where the protrusion is located by a predetermined distance. For this reason, the sheet protrusion does not interfere with the discharge means and hinders the discharge, and
The stacking stability of the sheets stacked on the stacking means is not deteriorated, and the stacking failure does not occur. According to the second aspect of the present invention, since there is provided the lifting / lowering drive means for individually lifting / lowering each of the divided loading members, the operation of lowering the divided loading member on the side where the protrusion is located by the lifting / lowering drive means is automated. It is possible to prevent the protrusion from interfering with the discharging means and to prevent a stacking defect from occurring. According to the third aspect of the present invention, since the position detecting means for detecting the position of the uppermost surface of the sheets stacked on the divided stacking members is arranged in a distributed manner, the sheets stacked on the divided stacked members are stacked. The position of the protruding portion of the sheet that has been detected can be detected, and based on the detection result, only the divided stacking member on the side where the protruding portion is located can be lowered until it is no longer detected by the position detecting device, and the protruding portion interferes with the discharging device. In addition, it is possible to prevent the occurrence of a loading defect. According to the fourth aspect of the present invention, the position detecting unit detects the position of the uppermost surface of the sheet on one of the divided stacking members, and raises and lowers the divided stacking members individually according to a result of the detection. Is controlled to lower the one of the divided stacking members, so that only the divided stacking member on the side where the protruding portion is located can be lowered based on the detection result until the position detecting unit no longer detects the divided stacking member. Can be prevented from being interfered with each other and a loading defect can be prevented. Claim 5
According to the invention, since the height detecting means for detecting a step between the plurality of divided stacking members is provided, it is possible to prevent the descending distance of the divided stacking member on the lowered side from becoming too large, It is possible to prevent the stacked sheets from falling due to the increase.

According to the sixth aspect of the present invention, when the height detecting means detects that the step between the divided stacking members has reached a predetermined limit distance, the warning means for issuing a warning is provided. Can call attention to the elderly. According to the invention of claim 7, when the height detecting means detects that the step between the divided loading members has reached a predetermined limit distance, all the divided loading members are simultaneously lowered. Therefore, it is possible to prevent the stacked sheet from dropping and the like from being further increased. According to the invention of claim 8, after detecting that the step has reached the limit distance, the discharging operation by the discharging means is stopped, so that further discharging failure or stacking failure occurs. Will not be done. According to the ninth aspect of the present invention, after the step is detected to have reached the limit distance, one of the divided stacking members forcibly lowers the other divided stacking member while maintaining the limit distance. Since the lowering mechanism is provided, the lowering operation can be performed while maintaining the limit distance by a simple mechanical mechanism without using electric control. According to the tenth aspect of the present invention, the position detecting means detects the positions of a plurality of uppermost surfaces along the width direction of the trailing edge of the sheets stacked on the divided stacking member. The detection operation is performed in response to the fluctuation, the fluctuation of the position of the protrusion, and the like, and the optimal divided stacking member that matches the position of the protrusion can be lowered. Claim 1
According to the first aspect, the position detecting means is configured to be able to advance and retreat along the width direction of the trailing edge of the sheets stacked on the divided stacking member. It is possible to detect a protrusion that can be formed at any position in the width direction of the trailing edge of the sheet only by using the position detecting means. According to the twelfth aspect of the present invention, there is provided a post-processing means for performing post-processing of the sheet, and a discharge means for discharging the sheet post-processed by the post-processing means to the stacking means. When a protruding portion is formed at the trailing edge width direction end of the stacked sheet by various post-processes received, the protruding portion can be promptly detected and one of the divided stacking members can be lowered, and the protruding portion is discharged. It is possible to prevent a discharge failure and a stacking failure from occurring due to interference with the apparatus. According to the invention of claim 13, since the post-processing means is a binding means for performing a binding process on the sheet, the staples are stuck at the trailing edge of the stacked sheet on the stacking means.
Even in the case where the thickness of the end portion is increased to become a protruding portion, it is possible to prevent the protruding portion from interfering with the discharging means and causing a discharge failure or a stacking failure.

According to the fourteenth aspect of the present invention, the elevation driving means is controlled so as to select and lower the optimal divided stacking member in accordance with the difference in the binding position and the number of times of binding by the binding means. Even when the binding position by the binding means is changed, only the optimal divided stacking member corresponding to the position of the projecting portion formed corresponding to the changed binding position is lowered to prevent defective discharge and defective loading. it can. Claim 1
According to the fifth aspect of the invention, after the number of times of binding by the binding means reaches a predetermined number, the divided stacking member corresponding to the binding position by the binding means is lowered, so that the number of times of binding or ejection is reduced. The timing for lowering the divided stacking member on the side where the protruding portion is formed can be appropriately selected based on the number of sheet bundles. In addition, the number of the position detection units to be installed can be reduced, and the control can be simplified. According to the sixteenth aspect of the present invention, the image forming apparatus includes the image forming unit that forms an image on a sheet, and the discharging unit that discharges the sheet to the stacking unit. When the deformed portion is formed at the rear edge width direction end portion, the protruding portion formed on the stacking sheet can be quickly detected and one of the divided stacking members can be lowered, and the protruding portion interferes with the discharging means. As a result, it is possible to prevent discharge failure and loading failure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a sheet stacking apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a sheet stacking apparatus according to another embodiment of the present invention.

3 is a cross-sectional view illustrating a configuration of a main part of the sheet stacking apparatus of FIG. 2, and is a cross-sectional view of the sheet stacking apparatus including a sheet post-processing apparatus.

FIG. 4 is a perspective view illustrating a configuration of a main part of the sheet stacking apparatus according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of the operation of the sheet stacking device of FIG. 4;

FIG. 6 is an explanatory diagram of an operation of the divided stacking member according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram of an embodiment of the present invention including a height detecting unit.

FIG. 8 is an operation explanatory diagram of the embodiment in FIG. 6;

FIG. 9 is a view for explaining operations of a position detecting means, a divided stacking member, a height detecting means, and the like according to the present invention.

FIG. 10 is an explanatory diagram of the operation of the height detecting means according to the embodiment of the present invention.

FIG. 11 is a flowchart illustrating a control procedure of an embodiment using a plurality of position detection units.

FIG. 12 is a diagram showing an embodiment using a forced lowering mechanism according to the present invention.

FIG. 13 is a flowchart illustrating an example of an operation and a control procedure of the sheet stacking apparatus using the forced lowering mechanism of FIG. 12;

FIG. 14 is a diagram showing another embodiment of the position detecting means.

FIG. 15 is a diagram showing another embodiment of the position detecting means.

FIG. 16 is a diagram illustrating a main configuration of a sheet post-processing apparatus.

FIG. 17 is a diagram illustrating the configuration and operation of a sheet stacking apparatus according to another embodiment of the present invention.

18 is a flowchart illustrating an example of an operation and a control procedure of the sheet stacking apparatus according to the embodiment of FIG. 17;

FIG. 19 is a diagram illustrating a stacking operation of a conventional sheet stacking apparatus.

FIG. 20 is a diagram showing a state in which a protruding portion is formed on a stacking sheet.

FIG. 21 is a diagram illustrating a stacking operation of another conventional sheet stacking apparatus.

FIG. 22 is a diagram illustrating a state in which a protruding portion is formed on a stacking sheet.

FIG. 23 is an explanatory view of a conventional sheet stacking apparatus.

FIG. 24 is an explanatory diagram of the operation of the sheet stacking device of FIG. 23;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 sheet stacking device 2 sheet stacking means 3 stacking member, 3a split stacking member, 3a ₁ first split stacking member, 3a ₂ second split stacking member, 3b bracket, 3b ₁ bracket with first rack, 3b ₂ second
Bracket with rack, 3c pinion, 3c ₁
First pinion, 3c ₂ Second pinion, 3d Stopper 4 Elevating drive means 4a First motor, 4b Second motor 5 Position detecting means, 5a Sensor with filer, 5a ₁
Sensor with first filler, 5a ₂ Sensor with second filler, 5b Non-contact sensor, 5b ₁ Optical sensor, 5b ₁₁ First optical sensor, 5b ₁₂ Second optical sensor, 5c Feed screw, 5c ₁ Right screw part, 5
c ₂ left screw portion, 5d feed motor 6 height detection means, 6a warning means, 6b first height detection arm, 6b ₁ U shape detection unit, 6b ₂ first height sensor, 6b ₃ second height sensor, 6c second height detection arm 7 control means 10 sheet second processing apparatus 11 second processing means, 11a binding means 12 discharge means, 12a discharge port, 12b discharge roller pair, 13 moving means, 13a timing belt, 13b
Gear group, 13c guide shaft, 13d drive source 14 binding position detecting means 15 staple tray, 15a first fence, 15
b second fence, 15c second end fence 19 control panel 20 forced lowering mechanism, 50 image forming apparatus 51 image forming unit, 51a printer main body, 51a
₁ image carrier, 51a ₂ charging means, 51a ₃ exposure means, 51a ₄ developing means, 51a ₅ paper feeding means, 51a ₅₁
Paper feed roller, 51a ₆ paper feed cassette, 51a ₇ paper feed cassette, 51a ₈ registration roller, 51a ₉ transfer means, 51a ₁₀ fixing means, 51a ₁₁ transport means, 51a
₁₂ cleaning means, 51a ₁₃ image information storage device,
51b Scanner section, 51b ₁ Original loading table, 5
1b ₂ lamps, 51b ₃ mirrors, 51b ₃₁ mirror, 51b ₃₂ mirror, 51b ₃₃ mirror, 51b ₄
Image forming lens, 51b ₅ light receiver, 51c Image recording processing unit 52 Ejecting means 100 Sheet loading device 101 Exit 102 Loading area 103 Loading means 110 Sheet second processing device 111 Second processing means, 111a Binding means 112 Exit 150 Image Forming device 151 Image forming unit 152 Outlet

Claims (16)

[Claims] 1. A sheet stacking apparatus comprising: sheet discharging means for discharging a sheet; and sheet stacking means for receiving and stacking a sheet discharged from the discharging means.
The sheet stacking means includes: at least two divided stacking members divided in a width direction orthogonal to the sheet discharging direction; and elevating drive means for vertically driving at least one of the divided stacking members independently of the other. A sheet stacking device, comprising: 2. The sheet stacking apparatus according to claim 1, wherein the lifting drive unit individually drives the divided stacking members up and down. 3. A position detecting means for detecting a position of an upper surface of a sheet stacked over each of the divided stacking members,
3. The sheet stacking apparatus according to claim 2, wherein the divided stacking members are dispersedly arranged at positions corresponding to the respective divided stacking members. 4. The apparatus according to claim 1, wherein said position detection means detects the position of the upper surface of the sheet on one of said divided stacking members, and controls said elevation drive means to raise and lower said one divided stacking member. The sheet stacking apparatus according to claim 3, wherein the sheet stacking apparatus is driven. 5. The sheet stacking apparatus according to claim 1, further comprising height detecting means for detecting a step between the plurality of divided stacking members. 6. The apparatus according to claim 5, wherein said height detecting means includes a warning means for issuing a warning when detecting that a step between said divided stacking members is equal to or greater than a predetermined limit distance. The sheet stacking device as described in the above. 7. When the height detecting means detects that the step between the divided stacking members has reached the limit distance, the elevation drive means causes all the divided stacking members to simultaneously descend. The sheet stacking device according to claim 5 or 6, wherein 8. The sheet discharging operation of the discharging unit is stopped after the height detecting unit detects that the step between the divided stacking members has reached the limit distance. The sheet stacking apparatus according to 5, 6, or 7. 9. When the step between one of the divided stacking members and the other divided stacked member has reached the limit distance due to the lowering of one of the divided stacking members, the one of the divided stacking members is maintained while maintaining the limit distance. 5. The sheet stacking apparatus according to claim 1, further comprising a forced lowering mechanism for forcibly lowering the other divided stacking member in conjunction with the lowering. 10. The apparatus according to claim 3, wherein said position detecting means detects the positions of a plurality of upper surfaces along a width direction of a trailing edge of the sheets stacked on the divided stacking member.
Or the sheet stacking device according to 4. 11. The apparatus according to claim 3, wherein the position detecting means is configured to be movable along a width direction of a trailing edge of the sheets stacked on the divided stacking member. The sheet stacking device according to claim 1. 12. A post-processing means for performing post-processing of a sheet,
The sheet stacking apparatus according to any one of claims 1 to 11, further comprising a discharge unit configured to discharge the sheet post-processed by the post-processing unit to a sheet stacking unit. 13. The sheet processing apparatus according to claim 1, wherein the post-processing unit is a binding unit that performs a binding process on a sheet.
3. The sheet stacking device according to 2. 14. The sheet according to claim 13, wherein the lifting drive unit is controlled to select and lower an optimal divided stacking member in accordance with a binding position and the number of times of binding by the binding unit. Loading device. 15. The divided stacking member corresponding to the binding position by the binding means is lowered after the number of bindings by the binding means reaches a predetermined number. Sheet loading device. 16. The image forming apparatus according to claim 1, further comprising an image forming unit configured to form an image on a sheet, and a discharging unit configured to discharge the sheet to the sheet stacking unit. Sheet loading device.