JP4775151B2 - Buffer device and sheet processing apparatus using the same - Google Patents

Description

  The present invention relates to a buffer device used in a sheet processing apparatus such as a copying machine or a printer, and in particular, a buffer device capable of transporting a plurality of sheets while delaying a preceding sheet on which an image is formed, and The present invention relates to an improvement of a sheet processing apparatus using the same.

2. Description of the Related Art In recent years, with the progress of on-demand publishing and the like, an apparatus having a post-processing device (sheet processing device) such as a finisher that performs a binding function or a punching function in a subsequent stage of an image forming device (sheet processing device) has been actively used. .
As a method of attaching such a post-processing device as an optional device to the main body of the image forming apparatus, a sheet is folded in advance and a sheet bundle is formed on a sheet alignment tray, and then saddle stitching is performed. Is known (see, for example, Patent Document 1).

  However, in such a system, in order to maintain productivity at the time of image formation, for example, when a buffer function that can transport a sheet even when a stapling function such as saddle stitching is performed is added, The required space is required, leading to an increase in the size of the device itself.

Japanese Patent Laying-Open No. 2004-277036 (Embodiment of the Invention, FIG. 2)

  For this reason, when post-processing a sheet after an image has been formed, it has been required to add a buffer function in a space-saving manner in order to achieve both reduction in size of the apparatus and improvement in productivity.

On the other hand, as a buffer device that can convey a subsequent sheet in a superimposed manner while delaying the preceding sheet when conveying the sheet, the one shown in FIG. 11 is known.
In this figure, this buffer device is arranged on the downstream side of the sheet conveying path and is capable of returning and conveying the sheet, and the sheet returned from the first conveying roll 101 is the original sheet. The second transport roll 102 transports in a direction different from the transport path, and a switching guide 103 that guides the sheet returned from the first transport roll 101 to the second transport roll 102 side. Reference numeral 104 denotes an upstream conveyance roll that is on the upstream side and conveys the sheet.

Therefore, according to the buffer device having such a configuration, after the first sheet is returned from the first conveyance roll 101 to the second conveyance roll 102, the first conveyance roll 101 and the first conveyance roll 101 at a predetermined timing are used. By rotating the second conveyance roll 102 in the reverse direction and switching the switching guide 103, it becomes possible to convey the second sheet and the first sheet conveyed by the upstream conveyance roll 104, The conveyance time of the first sheet conveyed from the first conveyance roll 101 can be delayed.
However, if such a buffer device is used in the post-processing device, although the buffer function is possible, it occupies a large space, which makes the device easy to enlarge and cannot be applied other than the buffer function. For example, it is not possible to perform processing such as pre-folding.

  The present invention is to solve such a technical problem, and provides a buffer device capable of adding a crease function to the buffer function in a space-saving manner and a sheet processing apparatus using the same. .

In other words, as shown in FIGS. 1A to 1C, the present invention is provided along the sheet conveyance path R, and a plurality of sheets can be conveyed while being delayed by delaying the preceding sheet S <b> 1. such a buffer device, and the conveying member 1 capable of feeding back the sheet S1, the sheet S1 while being arranged sheet S1 to be carried in a direction crossing to the sheet transport path R at the upstream side of the conveying member 1 A fold conveying member 2 capable of nip conveyance from the end portion or in the middle of the sheet, and a sheet S1 which is disposed at a portion facing the fold conveying member 2 and is conveyed back from the conveying member 1 at its end. a guide member 3 for guiding the fold conveying member 2 from the parts or positions corresponding to the folding position, whether to creasing on the sheet S1, whether to buffer function, or do nothing through When the crease is to be selected, the conveyance member 1 is rotated in the reverse direction and the guide member 3 is advanced to the fold conveyance member 2 side so that the middle of the sheet S1 is nipped by the crease conveyance member 2 and pulled. After the conveyance and retraction of the guide member 3, the pull-in conveyance by the crease conveyance member 2 is canceled and the conveyance member 1 is rotated forward to convey the creased sheet S 1 along the sheet conveyance path R, and the buffer When performing the function, the conveying member 1 is rotated in the reverse direction and the guide member 3 is advanced to the fold conveying member 2 side so that the end of the preceding sheet S1 is nipped by the fold conveying member 2 and the sheet S1 is drawn and conveyed. After the guide member 3 is retracted, the pulling-in by the fold conveyance member 2 is performed at a timing when the succeeding sheet S2 overlaps the preceding sheet S1. When the conveyance is canceled and the conveyance members 1 are rotated forward to convey the overlapped sheets S1 and S2 along the sheet conveyance path R and do nothing, the sheet S1 is left as it is. And a control device that controls the conveyance member 1, the crease conveyance member 2, and the guide member 3 so as to convey along the sheet conveyance path R. Here, FIGS. 1A to 1C are schematic views showing the buffer function of the present invention, in which FIG. 1A is a state in which the preceding sheet S1 is being fed, and FIG. (C) shows a state in which two sheets S1, S2 are stacked and conveyed. Reference numeral S2 indicates a subsequent sheet. Needless to say, the present invention is not limited to the embodiment shown in FIG.

In such a technical means, a plurality of sheets (for example, S1 and S2) conveyed by the buffer device of the present case may be a plurality of sheets. Usually, one sheet is delayed and two sheets are overlapped with subsequent sheets. Be transported. Note that the overlapping timing may be appropriately selected.
Further, the conveying member 1 only needs to be able to return and convey the sheet S1, and may be, for example, a roll-shaped member or a belt-shaped member.
Further, the crease conveying member 2 only needs to be able to nip and convey the sheet S1, and may be a pair-shaped roll-shaped member or a pair-shaped belt-shaped member. Alternatively, a combination of a roll-shaped member and a belt-shaped member may be used. From the viewpoint of miniaturization, a pair-shaped roll member is preferable. Here, the “intersecting direction” is preferably a direction substantially orthogonal to the sheet conveyance path R, but may be any direction as long as the sheet S1 in the sheet conveyance path R can be conveyed to the crease conveyance member 2 side. It means that.

  And in this invention, it arrange | positioned in the site | part facing the crease conveyance member 2, and it was made to guide the sheet | seat S1 returned and conveyed from the conveyance member 1 to the crease conveyance member 2 side from the position corresponding to the edge part or crease position. By providing the guide member 3, the sheet can be easily conveyed to the fold conveying member 2.

  Moreover, in this invention, it is preferable that a part of fold conveyance member 2 serves also as a part of the conveyance member 1, and in this case, the apparatus configuration is further simplified.

  And as the guide member 3 of this invention, it is comprised with the folding knife which folds sheet | seat S1, It is preferable that this folding knife moves forward / backward across the sheet | seat conveyance path | route R, By moving a folding knife forward / backward in this way, The sheet S1 on the sheet conveyance path R can be easily guided to the nip area of the crease conveyance member 2 and can be appropriately performed not only in the buffer function but also in the crease function. become.

  Furthermore, it is preferable that the crease conveying member 2 and the guide member 3 of the present invention are also used as a crease forming device that creases the sheet S1. According to this, it is possible to selectively perform the crease function and the buffer function for the sheet S1 with a simpler configuration.

Further, the present invention is not limited to the buffer device described above, and is also intended for a sheet processing apparatus using the buffer device.
In this case, an image forming unit that is provided on the upstream side in the sheet conveyance direction of the buffer device and forms an image on the sheet S1, and a sheet bundle that is provided on the downstream side in the sheet conveyance direction of the buffer device and is conveyed is integrated. In the sheet processing apparatus including the sheet alignment tray capable of forming the above, the buffer apparatus described above may be provided as the buffer apparatus. The image forming method of the image forming unit is not particularly limited, and for example, an image forming method such as an electrophotographic method or an ink jet method is applied.
The sheet processing apparatus includes a sheet alignment tray that is provided on the downstream side of the buffer apparatus in the sheet conveying direction and that can stack the conveyed sheets S1 to form a sheet bundle, and includes the buffer apparatus described above as the buffer apparatus. What should I do? As described above, when the buffer device described above is provided for the aspect including the sheet alignment tray, a post-processing device capable of various post-processing such as binding processing can be easily realized. In particular, the saddle stitching process can be easily performed by pre-crease the sheet S1.

According to the present invention, a conveying member capable of returning and conveying a sheet, a crease conveying member capable of nip conveyance in a state where the sheet is directly or creased on the upstream side of the conveying member, and the fold conveying member are opposed to each other. A guide member that is disposed and guided back from the conveying member to the crease conveying member side from a position corresponding to the end portion or the crease position, and performs crease on the sheet, performs a buffer function, or anything And a control device that controls the conveying member, the crease conveying member, and the guide member in accordance with the selected contents, so that it can be applied to the sheet crease function. The buffer device configured as described above can be realized.
Further, by using such a buffer device, it is possible to realize a space-saving sheet processing device having both a crease function such as a pre-fold of the sheet and a buffer function of the sheet.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 2 shows an embodiment of a sheet processing apparatus to which the present invention is applied. In the figure, the sheet processing apparatus of the present embodiment is provided with an apparatus main body 10 having an image forming unit 20 capable of forming a color image, and an image reading unit 11 for reading a document above the apparatus main body 10. In addition, a document feeding device 12 for feeding a document to the image reading unit 11 is disposed above, while a sheet feeding cassette 14 for supplying a sheet as a recording material is accommodated in the lower portion of the apparatus body 10 so as to be drawable. The paper feeding unit 13 is disposed. Further, a finisher 40 that performs post-processing on a sheet on which an image is formed by the apparatus main body 10 is provided between the image forming unit 20 and the image reading unit 11. ing.
A part of the upper surface of the casing of the finisher 40 is formed with a discharge tray 40a capable of discharging and storing sheets output from the apparatus main body 10 so that the sheets discharged from the apparatus main body 10 can be stored. .

  The image forming unit 20 used in the present embodiment employs, for example, an electrophotographic system, and is yellow (Y color), magenta (M color), cyan (C color), and black (K color). The four-color image forming units 21 (21a to 21d) are arranged in parallel on the intermediate transfer belt 30 so-called tandem type. Therefore, the toner images of the respective colors formed by the respective image forming units 21 (21a to 21d) are sequentially primary-transferred and multiplexed on the intermediate transfer belt 30, and the multiplexed toner images are secondary-transfer device 35. Are collectively transferred onto the sheet conveyed from the paper feed cassette 14 and guided to the fixing device 37. The color arrangement of the four-color image forming units 21 is not limited to this order, and may be in other orders.

  The image forming unit 21 (21a to 21d) in the present embodiment includes a photosensitive drum 22 that forms and supports each color component toner image, a charger 23 such as a charging roll that charges the photosensitive drum 22, and a charged photosensitive member. A laser exposure device 24 that forms a latent image on the photoconductive drum 22, a developing device 25 that visualizes the electrostatic latent image on the photoconductive drum 22, and a toner image on the photoconductive drum 22 are primarily transferred onto the intermediate transfer belt 30. For example, a primary transfer unit 26 including a primary transfer roll and a drum cleaner 27 that cleans residual toner remaining on the photosensitive drum 22 are configured. In this embodiment, the laser exposure unit 24 exposes the entire four-color image forming units 21 (21a to 21d) with one laser exposure unit 24.

  The intermediate transfer belt 30 is stretched around a plurality of stretching rolls 31 to 34, and is circulated and conveyed using, for example, the stretching roll 31 as a driving roll. For example, a secondary transfer device 35 including a secondary transfer roll. However, the tension roll 34 is opposed to the backup roll. Further, a belt cleaner 36 for removing residual toner on the intermediate transfer belt 30 is disposed at a position facing the tension roll 31 of the intermediate transfer belt 30.

The sheet conveying system from the sheet feeding cassette 14 in the apparatus main body 10 is as follows. The sheet fed from the sheet feeding cassette 14 is conveyed downstream by the sheet feeding mechanism 15, and the conveyed sheet is positioned and regulated by the registration roll 16, and then the downstream sheet is conveyed at a predetermined timing. It is transported to the secondary transfer site (position of the secondary transfer unit 35). The toner images multiplexed on the intermediate transfer belt 30 are collectively transferred onto the sheet by the secondary transfer unit 35. The toner image transferred onto the sheet is fixed by the fixing device 37 and then discharged to the discharge tray 40 a via the transport roll 17 and the discharge roll 18.
Further, in the present embodiment, the second discharge roll 19 that discharges the sheet in a direction different from the discharge roll 18 side is provided between the fixing device 37 and the transport roll 17, thereby completing the fixing. The sheet can be conveyed to the finisher 40 side. Reference numeral 28 in the apparatus main body 10 is a toner replenishment bottle of four colors, and toner is appropriately supplied from these toner replenishment bottles 28 to the developing device 25 of the image forming unit 21 of each color.

  Further, the finisher 40 of the present embodiment has a carry-in roll 41 that is carried into the finisher 40 from the second discharge roll 19 on the apparatus main body 10 side, and has a feature point of the present case via a carrying roll 42 on the downstream side thereof. A certain buffer device 50 is provided with an end binding stapler 60 and a saddle stitching stapler 70 provided downstream thereof. Further, on the side wall side of the finisher 40, a stacker 71 capable of moving up and down to accommodate a sheet is provided.

  The buffer device 50 is on the downstream side of the sheet conveyance path, and is provided with a return conveyance roll 51 (51a, 51b) capable of returning and conveying a sheet, and a fold roll 52 that is paired with one of the return conveyance rolls 51 (51b). And a folding knife 53 is provided as a guide member that is provided across the sheet conveyance path at a position facing the nip area between the return conveyance roll 51b and the crease roll 52 and that can advance and retreat along the direction toward the nip area. It has been.

FIG. 3 shows the configuration of the buffer device 50 in the present embodiment, and also shows the transport roll 42 on the upstream side of the buffer device 50 at the same time.
In the present embodiment, one of the return conveyance rolls 51 (51 b) of the buffer device 50 is a drive roll, and can be rotated forward and backward by a motor 55. The other side (51a) of the return conveyance roll 51 is a driven roll, and is driven to rotate with respect to the drive roll 51b.
Further, the crease roll 52 is provided with, for example, a solenoid 56 so as to be able to come in contact with and separated from the drive roll 51b of the return conveyance roll 51, and the crease roll 52 is brought into pressure contact with or separated from the drive roll 51b by the forward and backward movement of the plunger 56a. (The positions indicated by solid lines and two-dot chain lines in the figure can be moved).

Further, the folding knife 53 is also provided with, for example, a solenoid 57 so that the folding knife 53 can be appropriately moved to the vicinity of the nip region between the fold roll 52 and the drive roll 51b of the return conveying roll 51 in accordance with the forward / backward movement of the plunger 57a. (The position indicated by the solid line and the two-dot chain line in the figure can be moved).
In the present embodiment, the method of performing the advance / retreat operation of the crease roll 52 and the folding knife 53 using a solenoid is shown, but the method is not particularly limited as long as the advance / retreat operation is possible. It can be used or a rack and pinion can be used.

  In the present embodiment, the transport roll 42 on the upstream side of the buffer device 50 is also driven by the motor 47. In addition, sensors 48 and 49 for obtaining passage information of the conveyed sheet are appropriately provided at predetermined positions on the sheet conveying path.

The control system in such a buffer device 50 is as follows.
FIG. 4 shows a control device 58 of the buffer device 50, which is composed of, for example, a CPU, a ROM, a RAM, and the like, and performs various processes. As such input information of the control device 58, a selection signal (crease / buffer selection) for selecting whether the buffer device 50 performs crease on the sheet, performs a buffer function, or passes through without doing anything. 59 is input from, for example, an operation panel (not shown) of the sheet processing apparatus. Further, sheet passing information at the sensors 48 and 49 is also input information.
On the other hand, as the output control performed from the control device 58, the motor 55 that drives the return conveyance roll 51, the solenoid 56 that performs the forward / backward movement of the fold roll 52, the solenoid 57 that performs the forward / backward movement of the folding knife 53, and the like are controlled. It is like that.

Further, in the present embodiment, as shown in FIG. 2, the end binding stapler 60 on the downstream side of the buffer device 50 binds the end of the sheet bundle accumulated on the compilation tray 61. The sheets stacked on the upper side are aligned by the paddle 62 (sheet rear end alignment is performed), and the ends of the aligned sheet bundle are bound.
Furthermore, the saddle stitching stapler 70 performs saddle stitching on the bundle of sheets arranged on the compilation tray 61. In this example, the saddle stitching stapler 70 can move up and down along the side wall of the finisher 40.
Furthermore, a plurality of transport rolls 43 to 46 for transporting sheets are provided in the sheet transport path of the finisher 40, the transport roll 45 is an exit roll to the compile tray 61, and the transport roll 46 is discharged from the finisher 40. It is a role.

  Next, the operation of the finisher 40 in the sheet processing apparatus of the present embodiment will be described. The sheet discharged from the apparatus main body 10 to the finisher 40 is accommodated on the compilation tray 61 from the exit roll 45 via the buffer device 50. By repeating this operation, the sheet bundle is accumulated on the compile tray 61, and after the edge bundle and the saddle stitch are bound, the sheet bundle is accommodated in the stacker 71 by the discharge roll 46. In addition, it can also be discharged from the discharge roll 46 to the stacker 71 as it is.

In the present embodiment, the buffer device 50 can be used as a crease function for folding a sheet. In this case, the buffer device 50 operates as follows.
5A to 5C show a state in which the sheet is pre-creased by the buffer device 50, and FIG. 5A shows a state in which the sheet is simply conveyed. At this time, the return conveyance roll 51 is rotated in the direction of the arrow in the figure, and the return conveyance roll 51b and the crease roll 52 are kept separated from each other, so that the crease roll 52 does not impair the conveyance of the sheet. ing. Further, the folding knife 53 is maintained in a state of being separated from the sheet. In this embodiment, the crease roll 52 is kept at a position separated from the sheet conveyance path. However, the present invention is not limited to this. For example, the crease roll 52 may be in contact with the sheet conveyance path. In order not to disturb the conveyance, it may be rotated in a driven manner or rotated in a direction in which the sheet is conveyed by a dedicated motor.

  Next, in order to make a crease at a predetermined position of the sheet, for example, after the front end of the sheet has passed through the sensor 49 on the downstream side of the return conveyance roll 51, the return conveyance roll 51 as shown in FIG. Operates in reverse. At this time, the fold roll 52 comes into contact with the drive roll 51b of the return conveyance roll 51 together with the reverse rotation operation of the return conveyance roll 51, and the folding knife 53 advances toward the sheet. Therefore, a part of the sheet is drawn into the nip area between the return conveyance roll 51b and the crease roll 52, and a part of the sheet is creased. At this time, the upstream conveying roll 42 rotates as it is to continue conveying the sheet.

  After that, as shown in (c), the folding knife 53 is retracted and the crease roll 52 is separated from the drive roll 51b of the return conveyance roll 51 at a predetermined timing, and the return conveyance roll 51 is also reversely rotated (forward rotation operation). I do. At this time, in the present embodiment, the upstream conveying roll 42 stops rotating for a predetermined time, and the sheet with the crease is conveyed downstream in the leading end direction of the sheet. When the conveying roll 42 rotates at a predetermined timing, the creased sheet is completely conveyed downstream. Needless to say, at this time, the conveying roll 42 may be rotated in the reverse direction without stopping.

The sheets that have been pre-creased in this way are aligned in the compile tray 61 so that, for example, alignment such as saddle stitching can be easily performed.
In the present embodiment, the pre-crease method is shown as the crease function by the buffer device 50. However, the present invention is not limited to this. For example, the sheet folded by the folding knife 53 is returned, and the drive roll 51b and the crease roll of the transport roll 51 It may be transported as it is from the nip region with 52 to the downstream side. However, it goes without saying that a conveyance system for conveying the folded sheet is required at this time.

Next, the buffer function by the buffer device 50 of the present embodiment will be described.
6A to 6D show the state of the buffer function by the buffer device 50. In FIG. 6A, the first sheet is conveyed by the return conveying roll 51 and is near the rear end of the sheet. Shows a state where the sheet is nipped by the return conveying roll 51.
Then, at a predetermined timing (for example, when a predetermined time elapses after the leading edge of the sheet passes through the sensor 49), the return conveying roll 51 is reversely rotated, and the crease roll 52 is brought into contact with the drive roll 51b of the returning conveying roll 51. The folding knife 53 is advanced. At this time, as shown in (b), when the folding knife 53 approaches the nip region between the crease roll 52 and the drive roll 51b of the return conveyance roll 51, the first sheet for which the return conveyance is started is The leading end in the advancing direction enters the nip region between the two while being guided by the folding knife 53, and is returned and conveyed as it is.
On the other hand, the second sheet gradually approaches the return conveyance roll 51 as shown in (c). Then, for example, at a predetermined timing after the leading edge of the second sheet passes through the sensor 48, the folding knife 53 moves backward (returns to the original), and the folding roll 52 is separated from the driving roll 51b of the return conveying roll 51 and returned. The transport roll 51 performs a reverse rotation operation (forward rotation operation), and as shown in (d), the second transport sheet is integrally returned with the second sheet overlapped with the lower surface side of the first sheet. 51 is transported downstream.

  In this way, the buffer device 50 of the present embodiment can exhibit the buffer function. In this embodiment, the second sheet is conveyed with a delay from the first sheet. However, the present invention is not limited to this, and the first sheet is conveyed with a delay from the second sheet. In this case, for example, the sheet nipped by the crease roll 52 and the drive roll 51b of the return conveyance roll 51 is conveyed to the downstream side as it is, and the two sheets conveyed by the upstream conveyance roll 42 are conveyed. If the return conveyance roll 51 is operated reversely immediately before the second sheet is nipped by the return conveyance roll 51, the second sheet can be stacked with a delay from the first sheet.

  By using such a buffer function, it is possible to delay the time for conveying the sheet to the compile tray 61 (see FIG. 2). To be able to spend. Therefore, it is not necessary to delay the sheet discharge from the apparatus main body 10, and good productivity can be maintained.

FIG. 7 shows an example of such a buffer function. For example, the sheet conveyance order (upper stage) for each page when four pages are bound and the sheet function when the buffer function is performed. The conveyance order (lower stage) is shown. In this example, when image formation in the apparatus main body 10 is sent to the finisher 40, the image forming order on the apparatus main body 10 side is the second page, first order because the face is down (the lower surface side is the image surface). The order is page, page 3, and page 4.
As shown in FIG. 2, when sheets discharged from the apparatus main body 10 in this order enter the finisher 40, the buffer device 50 performs a buffer function between the first two sheets (second page and first page). To work. As a result, as shown in FIG. 7, the second page passes through the buffer device 50 with the first page overlapped on the bottom and the second page of the first sheet overlapped on the top. The sheet bundle conveyed by overlapping two sheets from the buffer device 50 is sent from the exit roll 45 onto the compilation tray 61. Further, the third sheet (third page) and the fourth sheet (fourth page) are fed from the exit roll 45, and finally the four sheets are overlaid on the compilation tray 61. . At this time, the compile tray 61 is matched in the state where the first page, the second page, the third page, and the fourth page overlap in the order from the bottom. Thereafter, the end binding stapler 60 performs binding processing (stapling) to the end, and the sheet is discharged from the discharge roll 46 to the stacker 71.

The movement of the sheet during processing by the edge binding stapler 60 will be described in detail as shown in FIGS. FIGS. 8 and 9 are schematic views, and in particular, the position of the paddle 62 is slightly changed from FIG.
First, as shown in FIG. 8A, in a state where the sheet is not conveyed to the compile tray 61, the discharge roll 46 waits for the sheet to be carried in a clamped state.
Then, a sheet bundle (one in which the first page and the second page are overlapped) stacked by the buffer device 50 (see, for example, FIG. 6) is nipped from the transport roll 44 to the discharge roll 46 through the outlet roll 45. The conveyance is continued.
When the rear end of the two sheet bundles passes through the exit roll 45, it falls onto the compile tray 61 from the rear end side, and then the sheet bundle is turned into the compile tray 61 as shown in FIG. The upper side is advanced toward the stapler 60.

Then, as shown in FIG. 9A, the discharge roll 46 releases the clamp, and the sheet bundle is drawn into the end binding stapler 60 by the conveying force due to the rotation of the paddle 62, and the trailing end of the sheet is placed on the reference end surface 60a. It will be regulated by hitting. At this time, the third page passes through the transport roll 44 and the exit roll 45.
When the rear end of the sheet on the third page passes through the exit roll 45, the sheet falls to the compile tray 61 side and slides to the end binding stapler 60 side as it is, and as shown in FIG. By rotation, it comes to be pulled toward the reference end face 60a side. At this time, the sheet of the fourth page is conveyed by the conveying roll 44 and the outlet roll 45.
Thereafter, when the rear end of the sheet on the fourth page passes through the exit roll 45, it is drawn to the reference end surface 60a side of the end binding stapler 60 as in the third page. When all the four sheets are regulated on the sheet rear end side, the discharge roll 46 is clamped and the binding process is performed, whereby the four sheet bundle is completed. At this time, since the conveyance of the next sheet is delayed by the buffer device 50, the binding process is performed in this free time.
When the sheet bundle is completed, as shown in (c), the discharge roll 46 is rotated to discharge the sheet bundle and discharge it to the stacker 71 (see FIG. 2).

  In the present embodiment, the first and second pages are overlapped and conveyed by the buffer device 50, so that the processing time (staple time) for performing the end binding by the end binding stapler 60 can be earned. There is no loss of productivity on the side. Further, since the sheet crease process can be performed by the buffer device 50, the buffer function and the crease function can be used together with a simple configuration, and space saving can be achieved at the same time. .

  Further, in the present embodiment, when folding the sheet by the buffer device 50, the folding knife 53 is applied from the lower side of the sheet and the crease of the mountain fold is performed. It is also possible to crease the valley fold by applying the knife 53 from the upper side of the sheet. In this case, it goes without saying that the position and the like of the crease roll 52 are appropriately changed.

  FIG. 10 shows a modification of the buffer device 50 described above in the present embodiment. As a fold roll, a pair of roll members 54 (for example, the fold roll 52 shown in FIG. 51) and the return conveyance roll 51 are separated. Therefore, in this example, the paired roll member 54 can be rotated forward and backward by a motor (not shown).

Next, the buffer function of this example will be described with reference to FIGS.
The pair of roll members 54 in this example are provided opposite to the sheet conveyance path between the upstream conveyance roll 42 and the return conveyance roll 51 as shown in FIG. It arrange | positions in the position where the roll member 54 of a structure does not contact.

  And as shown in (b), the return conveyance roll 51 is the timing when predetermined time passes after the front-end | tip of the sheet conveyed by the sensor 49 is detected, ie, the 1st sheet conveyed The reverse operation is started at a predetermined timing before the rear end of the rear end passes through the return conveyance roll 51. At this time, the folding knife 53 advances to the paired roll member 54 side, and the rear end (front end in the advancing direction) of the first sheet conveyed back is guided to the paired roll member 54 side by the folding knife 53. The The pair of roll members 54 are pushed into the nip region by the rotation of the paired roll members 54. On the other hand, the second sheet is transported by the upstream transport roll 42.

Thereafter, as shown in (c), the pair of roll members at a predetermined timing after the leading edge of the second sheet is detected by the sensor 48, that is, at a timing when the second sheet reaches a predetermined position. 54 starts reverse rotation, and the sheet once pushed in is directed toward the return conveyance roll 51 by the folding knife 53 and a guide (not shown).
Thereafter, the folding knife 53 is retracted and the second sheet is conveyed, so that the sheet is conveyed in a state where two sheets are overlapped on the return conveying roll 51 as shown in FIG.

Also in the buffer device 50 having such a configuration, a crease process similar to that of the above-described embodiment can be realized.
Therefore, it is possible to realize the buffer device 50 that can perform the buffer process and the crease process with a simple configuration.

(A)-(c) is a schematic diagram which shows the outline | summary of the buffer apparatus based on this invention. It is explanatory drawing which shows the sheet processing apparatus of embodiment to which this invention was applied. It is explanatory drawing which shows the buffer apparatus of embodiment. It is explanatory drawing which shows the control system of a buffer apparatus. (A)-(c) is explanatory drawing which shows a mode that a creasing process is performed by the buffer apparatus of embodiment. (A)-(d) is explanatory drawing which shows the buffer function of embodiment. It is explanatory drawing which shows an example of a buffer process. (A)-(c) is explanatory drawing which shows the conveyance state of the sheet | seat after a buffer process. (A)-(c) is the continuation of Drawing 6, and is an explanatory view showing the conveyance state of the sheet after buffer processing. It is explanatory drawing which shows the modification of the buffer apparatus of embodiment. It is explanatory drawing which shows the conventional buffer apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conveyance member, 2 ... Folding conveyance member, 3 ... Guide member, R ... Sheet conveyance path | route, S1, S2 ... Sheet

Claims (6)

A buffer device that is provided along a sheet conveyance path and is capable of conveying a plurality of sheets stacked with a delay of a preceding sheet,
A conveying member capable of returning and conveying the sheet;
A crease conveyance member that is arranged to be able to carry in a sheet in a direction intersecting the sheet conveyance path on the upstream side of the conveyance member and capable of nip conveyance with a crease from the end of the sheet or in the middle of the sheet ;
A guide member that is disposed at a portion facing the fold conveying member and guides the sheet returned and conveyed from the conveying member to the fold conveying member side from a position corresponding to the end portion or the crease position ;
Select whether to crease the sheet, perform a buffer function, or pass without doing anything,
When crease is performed, the conveying member is rotated in the reverse direction and the guide member is advanced to the fold conveying member side so that the middle of the sheet is drawn and conveyed by the fold conveying member, and the guiding member is retracted. And after releasing the pull-in conveyance by the crease conveyance member and causing the conveyance member to rotate forward to convey the creased sheet along the sheet conveyance path,
When performing the buffer function, the conveying member is rotated in the reverse direction and the guide member is advanced to the fold conveying member side so that the end of the preceding sheet is nipped by the fold conveying member and the sheet is drawn and conveyed. After the guide member is retracted, the pull-in conveyance by the crease conveyance member is released at the timing when the succeeding sheet overlaps the preceding sheet, and the conveyance member is rotated forward to move the overlapped sheet to the sheet conveyance path. Transport along
When passing without doing anything, the sheet is conveyed as it is along the sheet conveyance path.
A buffer device comprising: a control device that controls the transport member, the fold transport member, and the guide member . The buffer device according to claim 1, wherein
The buffer device, wherein the crease conveyance member and the guide member are also used as a crease device for crease the sheet. The buffer device according to claim 1, wherein
A part of the fold conveying member is also used as a part of the conveying member. The buffer device according to claim 1, wherein
The buffer device, wherein the guide member is configured by a folding knife that folds a sheet, and moves forward and backward across the sheet conveyance path. A buffer device according to any one of claims 1 to 4;
An image forming unit provided on the upstream side of the buffer device in the sheet conveying direction and forming an image on the sheet;
A sheet processing apparatus, comprising: a sheet aligning tray provided downstream of the buffer device in a sheet conveying direction and capable of collecting the conveyed sheets to form a sheet bundle. A buffer device according to any one of claims 1 to 4;
A sheet processing apparatus comprising: a sheet aligning tray provided downstream of the buffer device in a sheet conveying direction and capable of collecting the conveyed sheets to form a sheet bundle.

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