JP2007091350A - Sheet processing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently process sheets in a sheet processing device by correcting the skew of the sheets when delivering the sheets after forming the image thereon from an image forming device body to the sheet treatment device. <P>SOLUTION: A sheet P with an image formed thereon by an image forming device body A is delivered by a delivery roller 9, and delivers the sheet to a first conveying roller 150 on a sheet processing device B side. A fore-end of the sheet P under delivery by the delivery roller 9 is stopped at its nip part for a predetermined time by stopping the first conveying roller 150. The drive of the first conveying roller 150 is started based on the signal of a second control means for controlling the delivery roller 9 on the image forming device body A side, the skew of the sheet is corrected, and the sheet is conveyed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus that perform sort processing, stapling processing, punching processing, and the like on sheets.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer may be configured as a whole by connecting a sheet processing apparatus next to an image forming apparatus main body having an image forming unit for recording an image (for example, Patent Documents). 1). Here, the sheet processing apparatus performs various processes such as a sorting process for sorting sheets after image formation, a stapling process for binding a bundle of sheets made up of a plurality of sheets, and a punching process for punching a sheet by punching. Is.

  In the above-described image forming apparatus, the sheet on which the image is formed by the image forming unit of the image forming apparatus main body is discharged from the image forming unit main body by the discharging unit on the image forming apparatus main body side and is conveyed to the conveying unit on the sheet processing apparatus side. Supplied. That is, the image is transferred from the discharge unit on the image forming apparatus main body side to the conveying unit on the sheet processing apparatus side. In the sheet processing apparatus, the transferred sheet is subjected to the above-described sorting process, stapling process, punching process, and the like, and then discharged to the outside of the sheet processing apparatus.

JP-A-9-151025

  However, according to the above-described prior art, when skew is generated when a sheet is transferred from the image forming apparatus main body to the sheet processing apparatus, the sheet is conveyed to the downstream side as it is and various processes are performed. become.

  For this reason, there has been a problem that the sheet alignment is insufficient at the time of sorting processing and stapling processing, and the punching accuracy varies due to variations in punching positions.

  SUMMARY OF THE INVENTION Accordingly, the present invention provides a sheet processing apparatus and an image forming apparatus that correct sheet skew during delivery from the image forming apparatus main body to the sheet processing apparatus so that subsequent sheet processing can be performed satisfactorily. It is intended to provide.

  According to a first aspect of the present invention, in the sheet processing apparatus including a conveying unit that conveys the sheet delivered from the discharging unit on the image forming apparatus main body side, the leading end of the sheet being discharged by the discharging unit is stopped. The sheet is temporarily stopped by the conveying unit, a loop is formed on the sheet between the conveying unit and the discharging unit, and then the conveying unit is driven.

  The invention according to claim 2 is the sheet processing apparatus according to claim 1, further comprising a first control unit that controls an operation of the conveying unit, wherein the first control unit is discharging by the discharging unit. Based on a signal from a second control unit that controls the discharge unit on the image forming apparatus main body side after stopping the leading end of the sheet at the nip portion of the conveyance unit by stopping the conveyance unit. The driving of the conveying means is started.

  According to a third aspect of the present invention, in the sheet processing apparatus according to the second aspect, the first control unit sets a driving start timing of the conveying unit based on a conveying speed of the sheet delivered from the discharging unit. It is characterized by changing.

  According to a fourth aspect of the present invention, in the sheet processing apparatus according to the second aspect, the first control unit determines the drive start timing of the conveying unit based on the thickness of the sheet delivered from the discharge unit. It is characterized by changing.

  The invention according to claim 5 is the sheet processing apparatus according to claim 2, wherein the sheet processing apparatus has a plurality of sheet processing modes, and the first control unit is based on the sheet processing mode, The drive start timing of the conveying means is changed.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus main body having an image forming unit that forms an image on a sheet and a discharge unit that discharges the sheet after image formation, and a sheet that performs processing on the sheet discharged from the discharge unit An image forming apparatus including a processing device, wherein the sheet processing device is the sheet processing device according to any one of claims 1 to 5.

  According to the first aspect of the present invention, when the sheet is delivered from the main body of the image forming apparatus to the sheet processing apparatus, the leading end of the sheet being discharged by the discharging unit is temporarily stopped by the stopped conveying unit, and the conveying unit and the discharging unit A sheet is formed between the sheet processing apparatus, the sheet processing apparatus drives the conveying means to correct the skew of the sheet, and conveys the sheet. , Drilling treatment and the like can be performed satisfactorily. Further, since it is not necessary to provide another apparatus for correcting skew in the sheet processing apparatus, the configuration can be simplified and the apparatus can be made compact accordingly.

  According to the second aspect of the present invention, the driving of the conveying means of the sheet processing apparatus is started by a signal from the second control means on the image forming apparatus main body side, that is, the second control means for controlling the discharging means. That is, a skew correction loop is formed on the sheet between the discharge unit on the image forming apparatus main body side and the conveyance unit on the sheet processing apparatus side. Since it is controlled by the control means, it is possible to form an appropriate loop by controlling both with high accuracy.

  According to the third aspect of the invention, since the driving start timing of the conveying unit is changed based on the conveying speed of the delivered sheet, a loop having an appropriate size according to the conveying speed can be formed.

  According to the fourth aspect of the invention, since the drive start timing of the conveying means is changed based on the thickness of the delivered sheet, it is possible to form a loop having an appropriate size according to the thickness of the sheet.

  According to the fifth aspect of the invention, since the drive start timing of the conveying unit is changed based on the sheet processing mode, a loop having a size suitable for each sheet processing mode can be formed.

  According to the invention of claim 6, since the image forming apparatus includes the sheet processing apparatus according to any one of claims 1 to 5, the same effects as those of the sheet processing apparatus can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, what attached | subjected the same code | symbol in each drawing has the same structure or the same effect | action, The duplication description about these was abbreviate | omitted suitably.

<Embodiment 1>
FIG. 1 shows a schematic configuration of an example of a sheet processing apparatus and an image forming apparatus to which the present invention can be applied. FIG. 3 is a diagram schematically showing a longitudinal sectional view of the sheet processing apparatus and the image forming apparatus as viewed from the front side (side on which the user is positioned during operation).

  As shown in the figure, an image forming apparatus (an image forming apparatus in a broad sense) includes, for example, a copying machine A as an image forming apparatus main body (an image forming apparatus in a narrow sense), and a sheet processing apparatus B that processes a sheet P on which an image is formed. And.

  In this image forming apparatus, the copying machine A and the sheet processing apparatus B are each constituted by individual casings (frames), and the whole is configured by connecting these casings. These may be configured by being disposed in the same casing. In this case, the sheet processing apparatus B is a sheet processing unit that constitutes a part of the image forming apparatus. Here, in addition to the above-described copying machine, for example, a printer, a facsimile machine, a printing machine, and the like correspond to the narrowly defined image forming apparatus. The sheet processing apparatus B corresponds to a sorter, a stapler, a punching apparatus, a folding apparatus, a bookbinding apparatus, and other devices that process the sheet P after or before image formation. The sheet P is a thin sheet-like member that can be used for image formation. Examples of the sheet P include general copy paper (plain paper), cardboard, postcard, envelope, and transparent film.

  As described above, the image forming apparatus shown in FIG. 1 includes the copying machine A and the sheet processing apparatus B, and the sheet processing apparatus B sorts the sheets P image-formed by the copying machine A for each number of copies. And a finisher unit C capable of punching, and a stitcher unit D capable of folding and binding a plurality of sheets P by wire binding. Here, the stitcher unit D will be briefly described. Reference numeral 67 in FIGS. 1 and 2 denotes a lower roller pair, reference numeral 78 denotes a folding roller, reference numeral 79 denotes a protruding unit, reference numeral 104 denotes a discharge roller, and reference numeral 106 denotes a stacking tray. Reference numeral 107 denotes a pressing member.

  In the following, first, the overall configuration and operation of the image forming apparatus will be described, and then the finisher unit C of the sheet processing apparatus B will be described in detail.

[Entire configuration of image forming apparatus]
As shown in FIG. 1, the copying machine A has an ADF (automatic document feeder) 1 mounted thereon. The copying machine A optically reads a document automatically fed from the ADF 1 by the optical reading unit 2 and transmits the information as a digital signal to the image forming unit 3 to record an image on the sheet P.

  A plurality of sheet cassettes 4 storing sheets P of various sizes are mounted at the bottom of the copying machine A (however, only one sheet cassette 4 is shown in the figure). An image is formed on the sheet P conveyed from the sheet cassette 4 by the conveying roller 5 or the like by the electrophotographic system in the image forming unit 3. That is, for example, the photosensitive drum 3b exemplified as an image carrier is uniformly charged, and the surface of the charged photosensitive drum 3b is irradiated with laser light from the light irradiation unit 3a based on information read by the optical reading unit 2. An electrostatic latent image is formed. After the toner (developer) is attached to the electrostatic latent image and developed as a toner image, the toner image is transferred onto the sheet P. The sheet P on which the toner image has been transferred is conveyed to the fixing device 6 where it is heated and pressed to fix the toner image on the surface.

  In the single-sided recording mode in which an image is formed only on the surface, the sheet P after the toner image is fixed is conveyed to the sheet processing apparatus B by, for example, a discharge roller 9 exemplified as a discharge unit. On the other hand, in the double-sided recording mode in which images are formed on both the front and back surfaces, the sheet P having the toner image fixed on the front surface is reversed by the switchback and conveyed to the retransmission path 7, and then again the image forming unit 3. Then, a toner image is formed on the back surface, and is fixed by the fixing device 6, and then conveyed to the sheet processing apparatus B. The sheet P can be manually fed from the multi-tray 8 in addition to being fed from the sheet cassette 4.

  The finisher unit C in the sheet processing apparatus B shown in FIG. 2 can perform discharge processing according to each operation mode such as an offset mode, a punch mode, and a staple mode in addition to the normal discharge mode when discharging the sheet P. To do.

  Here, in the offset mode, when the sheets P are sorted and discharged for each number of copies, the side guide 11 (see FIG. 4) is moved to place the sheets P when the sheets P are discharged for each number of copies. This is an operation mode in which the sheet is discharged so that the boundary for each number of copies can be understood by shifting the sheet in the sheet width direction (a direction orthogonal to the sheet conveyance direction; hereinafter abbreviated as “width direction” as appropriate). If there is no space to move the sheet P by a predetermined amount with respect to the sheet width direction size, the reference guide 37 is temporarily retracted below, for example, the staple tray 12 exemplified as the stacking unit, and the sheet movement amount is sufficiently increased. Secure.

  The staple mode is an operation mode in which when the sheets P are sorted and discharged for each number of copies, they are stacked and aligned on the staple tray 12, stapled by the stapler 13, and bound and discharged for each number of copies. is there.

  In the above-described sheet discharge, in addition to the normal discharge control for discharging the sheets P one by one, multiple sheet discharge control capable of discharging a large number of sheets P at the same time is possible. In this multi-sheet discharge control, the sheet P sent from the copying machine A to the sheet processing apparatus B stays in the buffer path 14 (see FIG. 2) provided in the finisher unit C, and is subsequently discharged. This is an operation control in which a large number of sheets are discharged simultaneously with P.

  Further, in the punch mode, the sheet P is temporarily stopped by a punch unit (not shown), the punch operation is performed, and then the above-described offset mode and staple mode processes are performed.

  Next, the configuration of each part of the finisher unit C in the sheet processing apparatus B will be described in detail.

  The sheet P on which an image is formed in the copying machine A is discharged from the copying machine A by the discharge roller 9 and supplied to the finisher unit C. The supplied sheet P passes through, for example, the guide guide 10 serving as a guide guide unit that receives the sheet P, is brought into contact with a nip portion of a first transport roller 150 exemplified as a transport unit, and the first transport is performed after a predetermined time has elapsed. It is nipped by the first conveying roller 150 by a driving means (not shown) and conveyed downstream. At this time, the sheet P spans between the discharge roller 9 and the first conveyance roller 150, and forms a loop inside the guide guide 10 while being in contact with the first conveyance roller 150. Thus, when the sheet P is conveyed after the first conveying roller 150 is restarted, the skew of the sheet between the copying machine A and the sheet processing apparatus B is corrected. Here, the operation of the first conveyance roller 150, that is, the rotation start and rotation stop timing and the rotation speed are controlled by the CPU 152 exemplified as the first control unit, for example. The CPU 152 stores a program for controlling these and the like. The CPU 152 also controls the entire sheet processing apparatus B. Note that the control of the entire sheet processing apparatus B including the operation of the first conveying roller 150 may be performed by control means (not shown) on the copier A side instead of being performed by the CPU 152. The first transport roller 150 that needs to be synchronized with the discharge roller 9 on the copier A side is controlled by a control unit on the copier A side that controls the discharge roller 9. Also good.

  Here, when the control is arranged, the following pattern can be considered in the present invention.

  (1) The entire copying machine A and the entire sheet processing apparatus B are controlled by the control signal of the control means on the copying machine A side.

  (2) The entire copying machine A and the entire sheet processing apparatus B are controlled by a control signal from the CPU 152 on the sheet processing apparatus B side.

  (3) The entire copying machine A and the first conveying roller 150 of the sheet processing apparatus B are controlled by the control signal of the control means on the copying machine A side, and the parts other than the first conveying roller 150 in the sheet processing apparatus B are controlled. Control is performed by a control signal from the CPU 152 on the sheet processing apparatus B side.

  (4) The entire sheet processing apparatus B and the discharge roller 9 of the copying machine A are controlled by the control signal of the CPU 152 on the sheet processing apparatus B side, and the control other than the discharge roller 9 on the copying machine A side is controlled on the copying machine A side. Control by means of a control signal.

  Particularly in the cases (3) and (4), the discharge roller 9 on the copier A side and the first conveying roller 150 on the sheet processing apparatus B side are connected to the same control means signal on the copier A side or the sheet processing apparatus B. Since the control is performed according to the signal from the same CPU 152 on the side, control with higher accuracy can be performed as compared with the case where control is performed using a different one.

  Furthermore, the drive start timing of the first conveyance roller 150 may be changed according to the conveyance speed of the sheet P delivered from the discharge roller 9 to the first conveyance roller 150. For example, when the transport speed is fast, the drive start timing is advanced compared to when the transport speed is slow. Thereby, when the size and thickness of the sheet P are the same, it is possible to form loops having substantially the same size.

  Further, the drive start timing of the first conveying roller 150 may be changed depending on the thickness of the sheet P delivered from the discharge roller 9 to the first conveying roller 150. For example, since a thick sheet P is less likely to form a loop than a thin sheet P, the drive start timing is delayed to allow sufficient time for forming the loop.

  Further, the driving start timing of the first conveying roller 150 may be changed based on the sheet processing mode. For example, in the case of the above-described offset mode, it is not necessary to sufficiently sufficiently perform the skew correction when the sheet P is delivered. In the staple mode, since the sheet P is aligned before stapling, it is not necessary to sufficiently correct the skew when the sheet P is delivered. In these cases, the drive start timing of the first conveyance roller 150 is advanced. On the other hand, in the above-described punch mode (drilling mode), the sheets are not aligned before drilling. Therefore, in this case, the drive start timing is delayed and the sheet P is inclined when the sheet P is delivered. Make sure the line is well corrected.

  The sheet P in which the skew has been corrected passes through, for example, the sheet detection sensor 27 serving as a sheet detection unit that detects the state of the sheet P, is guided to the first flapper 21, and is disposed on the downstream side. It is further conveyed downstream by a roller 151. Thereafter, the sheet P is conveyed by the conveying roller 15 and discharged onto the stack tray 18 by the upstream discharge roller pair 16 and the downstream discharge roller pair 17. A plurality of stack trays 18 are provided so as to be movable in the vertical direction, and are moved in the vertical direction by a drive source (not shown) built in the lower part thereof. In the case of the sort discharge, the plurality of stack trays 18 are sequentially moved to the discharge port 36, whereby the sheets P can be discharged in a state of being sorted for each number of copies. Further, in the offset mode and the staple mode, it is possible to perform an offset process or a staple process on one stack tray 18 and discharge in a sorted state. Further, it is possible to punch the sheet P by mounting a punch unit for each of the modes described above. The stack tray 18 is provided with a stack sensor 53 (see FIG. 4) that detects the presence or absence of the sheet P on the stack tray 18.

[Offset discharge processing]
As described above, the finisher unit C according to the present embodiment can perform the sorting process in the offset mode. In this mode, as shown in FIG. And the first sheet P1 of each part is shifted in the sheet width direction (arrow direction) with respect to the second and subsequent sheets P when the sheets are discharged in the unit of the number of copies. Is.

  Further, in the sorting process in the offset mode, the above-described control for shifting the first sheet P1 of each part in the width direction and the bundle offset mode for clarifying the boundary between the number of copies by shifting the entire sheet bundle in the sheet width direction. You can choose either.

  For this reason, the downstream discharge roller pair 17 includes a downstream discharge roller 17a provided in the finisher unit main body and a movable discharge roller attached to a swing guide 20 that can swing around the rotation axis with respect to the finisher unit main body. 17b. As shown in FIG. 3, when the swing guide 20 is opened upward, the downstream discharge roller pair 17 is separated. Further, an alignment unit that guides one end (side end) of two ends (side ends) along the conveyance direction of the sheet P between the upstream discharge roller pair 16 and the downstream discharge roller pair 17. The side guide 11 is disposed so as to be movable in the sheet width direction. Thus, in the offset mode, when the first sheet P1 of each number to be sorted is discharged, as shown in FIG. 4, the rear end of the sheet is the upstream discharge roller pair 16 and the downstream discharge roller pair 17. The swing guide 20 is opened upward when it is conveyed to the staple tray 12, and then the side guide 11 is moved in the direction of the arrow to move the first sheet P1 by a predetermined amount. Then, the swing guide 20 is closed and the sheet P1 is discharged to the stack tray 18. Note that the sheet P and the sheet P1 illustrated in the upper part in FIG. 4 are viewed from the direction of the arrow X when the sheets are stacked and aligned on the stack tray 18. Thereafter, the second and subsequent sheets P are normally discharged, and as shown in FIGS. 3 and 4, the first sheet P1 of each number of copies is discharged in a shifted state. As described above, when there is no space for moving the sheet P by a predetermined amount with respect to the size in the sheet width direction, the reference guide 37 is retracted below the staple tray 12 to ensure a sufficient amount of sheet movement.

  In the bundle offset mode, according to the above-described configuration, the sheets P to be sorted are stacked and aligned on the staple tray 12, and when the plurality of sheets P are collected, the side guide 11 is moved in the direction of the arrow. The sheet P is moved by a predetermined amount. Thereafter, for the sheet bundle to be offset, the above-described operation is repeated to clarify the boundary for each bundle.

  Next, the two-sheet discharge control will be described. If the second sheet P is conveyed from the copying machine A to the finisher unit C while the first sheet P is being offset, as shown in FIG. Since the upstream end of the flapper 22 is positioned downward, the second sheet P is sent to the buffer path 14. The preceding sheet P2 sent to the buffer path 14 (the second sheet in the case of the offset mode) is driven to the buffer roller 23 by the buffer roller 23 that rotates and the buffer roller 24 that rotates by driving the sheet P against the buffer roller 23. It is sent in the direction of the arrow shown in the figure. Here, the third flapper 25 swings so that the preceding sheet P2 is fed in a direction in which the preceding sheet P2 is wound around the buffer roller 23.

  Further, the leading edge of the preceding sheet P2 is detected by the buffer sensor 26, and when the leading edge of the preceding sheet P2 reaches a predetermined position, the driving of the buffer roller 23 is stopped and the preceding sheet P2 is stopped in the buffer path 14. As shown in FIG. 5, when the succeeding sheet P3 (the third sheet in the offset mode) enters, the buffer roller 23 starts rotating, and as shown in FIG. 6, the preceding sheet P2 and the succeeding sheet P3 are stacked and conveyed. Further, when the trailing edge of the preceding sheet P2 passes the position of the third flapper 25, the third flapper 25 swings so that the two sheets P2, P3 are fed in the direction of the upstream discharge roller pair 16, and the sheet The two P2 and P3 are stacked and discharged onto the stack tray 18.

  By performing the above two sheet discharge control operation, the sheet P is not discharged from the upstream discharge roller pair 16 during the offset processing operation. For this reason, it is not necessary to stop the operation of the copying machine main body. For this reason, processing time does not become long also in offset mode, and quick offset discharge is attained.

  In this embodiment, one sheet P is wound around the buffer roller 23. However, in order to further increase the time for performing the offset processing operation, two or more sheets P are wound and three or more sheets P are wound. It is also possible to discharge at the same time. Further, the sheet P wound around the buffer roller 23 can be discharged and stacked only by the sheet P wound around the buffer roller 23 without the subsequent sheet P.

  Further, the case where the sheet P to be offset is the first sheet P of each part at the time of sort processing in the offset mode has been described as an example. However, the present invention is not limited to this. For example, the last sheet P of each part Even if the offset is offset, the present invention is effective. Further, the number of sheets P to be offset is not limited to one, and a plurality of sheets may be used.

  Further, the above-described two-sheet discharge control is performed not only at the time of offset processing, but also at the time of stapling processing in a stapling mode to be described later, so that the time required for stapling processing can be used effectively.

  The two-sheet discharge control described above is effective when performed during offset processing or stapling processing, which will be described later. However, the two-sheet discharge control may be performed in other cases. On the contrary, it is naturally possible to set so that the two-sheet discharge control is not performed.

[Loading on staple tray]
In the staple mode, as shown in FIG. 8, the swing guide 20 is opened, and after the sheet P is discharged to the staple tray 12 by the upstream discharge roller pair 16, the paddle 31 provided on the swing guide 20 and The knurled belt 32 that is rotated by driving the upstream discharge roller pair 16 is rotated in the direction of the arrow to return the sheet to the position where the trailing edge of the sheet contacts the trailing edge stopper 33. Then, the sheet P is pushed into one side by the side guide 11 and aligned, and then stapled by the stapler 13.

  When discharging the sheet P to the staple tray 12, if the upstream discharge roller pair 16 has a high discharge speed, the swing guide 20 is open, so the sheet P that has passed through the upstream discharge roller pair 16 pops out. In other words, it is excessively advanced forward (in the direction of the stacker tray), and it takes time to pull it back. In addition, when the sheet P advances too far forward, even if it is pulled by hitting it with the paddle 31, it does not return to the knurled belt 32, and there is a possibility that alignment on the staple tray 12 cannot be performed.

  Therefore, in the present embodiment, in the staple mode, when the trailing edge of the sheet passes through the upstream discharge roller pair 16, the rotation speed of the upstream discharge roller pair 16 is controlled to be low. As a result, the sheet P discharged to the staple tray 12 falls at the rear end of the sheet in the vicinity of the knurled belt 32, and is reliably pulled in by the rotation of the paddle 31 and the rotation of the knurled belt 32. Can be performed.

  Note that whether or not the trailing edge of the sheet passes through the upstream discharge roller pair 16 can be determined by detecting a motor rotation speed for a predetermined time after the sheet P passes a predetermined sensor.

  Further, after the trailing edge of the sheet falls on the staple tray 12, the rotation of the upstream discharge roller pair 16 that has been switched to the low speed driving is switched at a high speed. Since the upstream discharge roller pair 16 is also a drive source for rotating the knurled belt 32, the sheet P that has fallen into the staple tray 12 is quickly pulled back by the knurled belt 32, and the trailing edge of the sheet is abutted against the trailing edge stopper 33. It becomes like this.

  As described above, in the staple mode, as a whole, quick alignment is possible by reducing the conveyance speed only when the trailing edge of the sheet passes the upstream discharge roller pair 16.

[Swing guide]
Here, the swing guide 20 will be briefly described with reference to FIG. The swing guide 20 rotatably holds the movable discharge roller 17b, and swings downward with a swing shaft 20a as a fulcrum by a drive mechanism 39, which will be described later, when discharging the sheet. Pressure contact. Similarly, in the staple mode, the drive mechanism 39, which will be described later, swings upward with the swing shaft 20a as a fulcrum, thereby separating the above-described moving discharge roller 17b from the downstream discharge roller 17a. In other words, the swing guide 20 functions as a switching unit that sets the downstream discharge roller pair 17 including the moving discharge roller 17b and the downstream discharge roller 17a to a sheet discharge enabled state or a sheet discharge disabled state.

  In FIG. 7, reference numeral 34 denotes a stopper provided with a shutter portion 34a. When the stack tray 18 is moved, the link 35 rotates upward with the rotation shaft 35a as a fulcrum and is formed at the upper end. The discharge port 36 is closed by raising the portion 34a. Thus, when the stack tray 18 passes through the discharge port 36, the sheets P (or sheet bundles) stacked on the stack tray 18 are prevented from flowing back to the discharge port 36. In the stopper 34, when the sheet is discharged, the link 35 rotates downward with the rotation shaft 35a as a fulcrum to open the discharge port 36.

[Stack tray operation during 2-sheet discharge control]
Next, the operation of the stack tray 18 when there are only two sheets P to be stapled will be described with reference to FIG. FIG. 7 is a cross-sectional view of the main part showing the position of the stack tray.

  Normally, when performing the stapling process, a plurality (two or more) of sheets P sequentially discharged onto the staple tray 12 are discharged on the staple tray 12 by the paddle 31 and the knurled belt 32 that are stacked and aligned. The sheet is pulled back in the opposite direction, and the trailing end of the sheet is abutted against the trailing end stopper 33 to be aligned. At this time, the stack tray 18 is lifted so that the front end side of the sheet P is above the rear end side on the staple tray 12 (a broken line position in FIG. 7), and the above-described sheet P can be easily pulled back using gravity. I am doing so.

  However, when there are only two sheets P to be stapled (including the case of the above-described two-sheet discharge control), the lower sheet P rotates in reverse with the swing of the swing guide 20 by the drive mechanism 39 described later. The downstream discharge roller 17a pulls back the staple tray 12 in the direction opposite to the discharge direction, while the upper sheet P is similarly pulled back in the direction opposite to the discharge direction by a paddle 31 and a knurled belt 32 described later. Therefore, since the sheet P discharged to the first sheet and the second sheet can be brought back and aligned without using gravity, the stack tray 18 is raised and the leading edge of the sheet P is aligned. There is no need to lift.

  Therefore, in the present embodiment, when there are only two sheets P to be stapled (including the case of the two-sheet discharge control), the stack tray 18 is not raised or lowered (raised). That is, when there are three or more sheets P to be stapled, the stack tray 18 is raised from the solid line position in FIG. 7 to the broken line position, but when there are only two sheets P to be stapled, the stack tray 18 is The pull-back operation is performed as described above while maintaining the solid line position in FIG. 7 without being raised.

  With this configuration, it is not necessary to raise and lower the stack tray 18 when stapling a sheet bundle composed of two sheets P. Therefore, the time required to raise the stack tray 18 can be saved, and the processing time can be greatly increased. Can be reduced.

[Swing amount of swing guide and paddle shape]
Next, referring to FIGS. 8 to 10, a paddle 31 that pulls back the sheet P discharged onto the staple tray 12 in a direction opposite to the discharge direction, and a swing guide that rotatably supports the paddle 31. The amount of rocking 20 will be described. 8 and 9 are enlarged views of main parts showing the state of the swing guide 20 and the paddle 31 when the sheet P is pulled back, and FIGS. 10A to 10G are explanatory views showing the shape of the paddle.

  The swing guide 20 is rotatably provided with a paddle 31 for pulling back the sheet P discharged onto the staple tray 12 in the direction opposite to the discharge direction. The paddle 31 rotates in the direction opposite to the sheet discharge direction every time one sheet P is discharged onto the staple tray 12 when the swing guide 20 is opened, and is placed at the rear end portion of the sheet P on the staple tray 12. The sheet P is elastically deformed by contact, and the sheet P is pulled back by a frictional force generated between the sheet P and the sheet P.

  Here, when the above-described swing guide 20 is swung upward and pulled back by the paddle 31 every time the sheet is discharged while being held at a fixed position, the sheets P are discharged onto the staple tray 12 one after another. Therefore, according to the change in the height (level) of the sheet P on the staple tray 12, the contact area and the contact pressure of the paddle 31 in contact with the uppermost sheet P change, and the sheet P is returned too much. There is a risk.

  Therefore, in the present embodiment, the above-described paddle 31 is configured to keep the contact pressure with respect to the uppermost sheet P discharged onto the staple tray 12 substantially constant. More specifically, the shape of the paddle 31 is formed into a tapered shape with the tip portion 31a narrowed as shown in FIGS. 10A shows a case where a stepped portion is provided on both surfaces of the leading end portion 31a of the paddle 31 to form a tapered shape, and FIG. 10B shows the one surface (the sheet P contact surface side) of the leading end portion 31a of the paddle 31. When the stepped portion is provided to have a tapered shape, FIG. 10C illustrates a case where the stepped portion is provided on the other surface (sheet non-contact surface side) of the paddle 31 to be tapered. The tapered shape of the tip 31a of the paddle 31 is not limited to the shape shown in FIG.

  By forming the paddle 31 in this way, the leading end 31a of the paddle, which is a contact portion with the sheet P, is easily elastically deformed when in contact with the sheet P, and a stable return force is obtained regardless of the number of stacked sheets P. And durability is further improved.

  Further, in the present embodiment, a plurality of the paddles 31 described above are provided in the rotation direction, and the paddle 31 is configured to contact a single sheet P a plurality of times by one rotation. Accordingly, for example, when the paddle 31 is brought into contact with the relatively large size sheet P twice and pulled back, only one rotation is required, so that the processing time is longer than when one paddle 31 is rotated twice. It can be shortened. FIG. 10A illustrates the case where two paddles 31 are provided in the rotational direction (twin paddles), but is not limited thereto. Further, even if the paddle 31 is shaped as shown in FIGS. 10D, 10E, 10F, and 10G, the same effect can be obtained.

  Further, the contact area of the paddle 31 with the sheet P discharged onto the staple tray 12 may be kept constant. More specifically, the swing amount when the swing guide 20 is opened (when swinging upward) is changed in accordance with the change in the height (level) of the sheet P on the staple tray 12. Specifically, for example, the contact area of the paddle 31 with respect to the uppermost sheet P is made constant by swinging the swing guide 20 upward as the number of discharged sheets P to the staple tray 12 increases. It keeps in.

  In the configuration shown in FIG. 9, the distance from the swing center (swing shaft 20a) of the swing guide 20 to the rotation center of the paddle 31 is r, the swing angle of the swing guide 20 is θ, and the thickness of the sheet bundle is This thickness t can be expressed as t = rsin θ, where t is t. Therefore, based on this equation, the swing amount (swing angle θ) of the swing guide 20 may be changed in accordance with the change in the thickness t of the sheet bundle.

  With this configuration, the contact area between the uppermost sheet P on the staple tray 12 and the paddle 31 is always kept constant regardless of the number of stacked sheets P, so that a stable return force can be obtained. Thus, it is possible to prevent the sheet P from returning too much due to a change in the contact area of the paddle 31 with the sheet P.

[Movement speed of side guide according to sheet size]
Next, the moving speed of the side guide 11 that performs alignment in the width direction of the sheet P will be described. When the sheets P are stacked on the staple tray 12, the sheet conveyance direction is aligned by the paddle 31 and the knurled belt 32 as described above, and the sheet trailing edge side (side edge on the trailing edge stopper 33 side) is aligned by the side guide 11. Part) is pressed to move the sheet P in the width direction toward the reference guide 37 on the opposite side, thereby aligning in the sheet width direction. Here, when the size of the sheet P is large, the center of gravity of the sheet P is far from the pressing position by the side guide 11 and the inertia is high due to the large mass. Cannot follow, and the sheet P may be misaligned.

  Therefore, in the present embodiment, the moving speed in the sheet width direction by the side guide 11 is changed according to the sheet size. More specifically, the side guide 11 is moved at a low speed when the sheet P is relatively long in the direction (sheet conveyance direction) orthogonal to the movement direction (sheet width direction) of the side guide 11 described above. ing. Specifically, for example, as shown in FIG. 11, sheets P of A4, LTR, and B5 sizes with a short length in the sheet conveying direction, and A3 and LDR sizes with a small amount of movement in the sheet width direction. In this case, the side guide 11 is moved at a high speed, and the other lengths of B4 and LGL, and the sheet P of each size of A4R and LTRR having a large amount of movement in the sheet width direction are used. The moving speed of the side guide 11 is low.

  With this configuration, the influence of inertia can be reduced, and the alignment in the width direction can be improved even for a large-sized sheet P (a sheet P having a long length in the transport direction). It is also effective for a sheet size having a large amount of movement in the sheet width direction.

[Pressing control of side guide]
Next, alignment in the width direction of the sheet P by the side guide 11 will be described. As shown in FIG. 12, the sheet P is aligned in the width direction by pressing one side end portion on the sheet rear end side by the side guide 11 and moving the sheet P in the width direction. This is done by hitting the guide 37. At this time, the sheet P moved in the width direction by the side guide 11 is in contact with the knurled belt 32. For this reason, the knurled belt 32 may be moved along with the sheet P moved in the width direction by the side guide 11, and the sheet P does not reach the reference guide 37 due to the influence of the knurled belt 32, resulting in mismatch. There is a fear.

  Therefore, in the present embodiment, as shown in FIGS. 13 and 14, when the side guide 11 performs alignment in the width direction of the sheet P (particularly in the R-type sheet P having a large width alignment amount), this side is used. By pressing the guide 11 stepwise as shown by the solid line and the broken line, the sheet P is aligned while reducing the influence of the knurled belt 32. That is, by pressing the sheet P step by step with the side guide 11, even if the knurled belt 32 is swung at the time of pressing, the knurled belt 32 can have a smaller wobbling width. It is easy to return to the position (state as shown in the figure), and the restoration time until the knurled belt 32 returns to the normal position can be shortened.

  Furthermore, the stepwise pressing control of the sheet P by the side guide 11 during the sheet width alignment is changed according to the size of the sheet P. Specifically, for example, as shown in FIG. 11, the pressing control of the first sheet P of each size of A4, LTR, B4, LGL and the second and subsequent sheets P of each size of LTR, B5. Is pushed in two steps.

  Here, the two-step pressing means that the first pressing (first step) is temporarily stopped and then the second pressing (second step) is performed. Note that the number of step presses is not limited to this. Further, the side guide 11 after the last pushing is configured to function as a guide for a certain period of time until the leading edge of the next sheet P reaches the downstream discharge roller pair 17 at the pushing position. That is, the sheet P remains pressed by the side guide 11.

  Further, when the side guide 11 presses the sheet P a plurality of times step by step, the side guide 11 stops once each time the sheet P is pressed, and after the elapse of time when the knurled belt 32 returns to the normal position (the twist returns). Subsequent pressing is started.

  Accordingly, by performing the alignment in the width direction by pressing the sheet P stepwise with the side guide 11 as described above, the effect of the knurled belt 32 can be quickly reduced and the alignment of the sheet P can be performed quickly and accurately. Can be done.

[Shape of knurled belt]
Next, the shape of the knurled belt 32 will be described with reference to FIGS. The knurled belt 32 further pulls back the sheet P that has been pulled back in the direction opposite to the sheet discharge direction by the paddle 31 described above, and aligns the sheet P with the trailing end stopper 33 to perform alignment in the sheet conveying direction. . Here, as shown in FIG. 15, when the contact surface of the knurled belt 32 with the sheet P is formed flat, the edge portion 32 a of the knurled belt 32 moves in the width direction when the side guide 11 presses the sheet. There is a possibility that the sheet P is caught and the sheet P is misaligned.

  Therefore, in the present embodiment, the edge portion 32a of the knurled belt 32 is tapered as shown in FIG. 16 (a), or the outer peripheral surface 32b of the knurled belt 32 is cross-sectionally shown in FIG. 16 (b). Molded into an R shape.

  By forming in this way, the resistance to the sheet P moved in the width direction by the side guide 11 at the time of alignment is reduced, and the misalignment of the sheet P due to the catch of the edge portion can be reduced.

[Restoring the knurled belt]
Further, as described above, the alignment of the sheet P in the width direction is performed by pressing one side end portion of the sheet rear end side by the side guide 11 and moving it in the width direction, and setting the other side end portion to the reference on the opposite side. The alignment is achieved by abutting against the guide 37. However, at this time, the sheet P moved in the width direction by the side guide 11 is in contact with the knurled belt 32. For this reason, the knurled belt 32 may be moved along with the sheet P moved in the width direction by the side guide 11, and the knurled belt is moved when the side guide 11 moves (withdraws) in the direction opposite to the sheet pressing direction. There is a possibility that the sheet P is moved by the restoration of the twist of 32 and becomes inconsistent.

  Therefore, in the present embodiment, even after the other side end portion of the sheet P hits the reference guide 37, the side guide 11 is continuously pressed until the knurled belt 32 returns to the normal position (the twist returns). After the knurled belt 32 returns to the normal position, the pressing of the sheet P by the side guide 11 is released.

  The side guide 11 functions as a guide for the next sheet P to be sent by continuing to press the sheet P at the position shown in FIG. 14, but the knurled belt 32 is not Return to the normal position while pressing. The side guide 11 is configured to retract to a retract position outside the sheet discharge area after the leading edge of the sheet P being guided approaches the downstream discharge roller pair 17.

  With this configuration, it is possible to prevent the sheet P from being misaligned due to the influence of the knurled belt 32.

[Pressure mechanism of swing guide and moving discharge roller]
Next, with reference to FIGS. 18, 19, and 20, a pressure mechanism for the swing guide 20 and the moving discharge roller 17b will be described. These drawings are views of the drive mechanism disposed on the back surface (rear surface) side of the sheet processing apparatus B as viewed from the back surface side. Accordingly, the left and right directions are opposite to those in FIGS.

  In these drawings, reference numeral 39 denotes a drive mechanism. The drive mechanism 39 opens and closes the swing guide 20 and drives the downstream discharge roller 17a to rotate forward and backward. The drive mechanism 39 includes a drive motor 40b that opens and closes the swing guide 20, a drive motor 40a that drives the downstream discharge roller 17a to rotate forward and backward, and a gear train, pulley, and the like that transmit drive force from the drive motors 40a and 40b. More composed of belts.

  Furthermore, the drive motors 40a and 40b are respectively provided with encoders 56a and 56b for detecting the number of rotations, and drive motor rotation detection sensors 55a and 55b. The rotation speed of each roller and the amount of movement of the swing guide 20 are determined. Detected. A swing open detection sensor 55c of the swing guide 20 is provided in the vicinity of the swing guide 20 to detect the open state of the swing guide 20.

  In this drive mechanism 39, the downstream discharge roller 17a is rotated forward (rotation in the sheet discharge direction) when the drive motor 40a is reversely rotated, and the downstream discharge roller 17a of the downstream discharge roller 17a is reversely rotated (sheet is rotated) when the drive motor 40a is rotated forward. The rotation is controlled in the direction opposite to the discharge direction. In addition, the swing guide 20 is controlled to open when the drive motor 40b is rotated forward, temporarily stopped when the drive motor 40b rotates a predetermined amount, and further closed when the drive motor 40b is rotated forward.

  Further, an opening / closing arm 47 is fixedly attached to the swing guide 20. Further, a projection 46b is formed on the operating gear 46 to which the rotation of the drive motor 40b is transmitted via the gear train. A swinging pressure spring (tensile spring) 110 is attached between the protrusion 46b and the above-described opening / closing arm 47. Thereby, the rocking guide 20 is pressurized and depressurized according to the rotation stop position of the protrusion 46b. Further, when controlling the pressure increase / decrease, the current value of the drive motor 40a driving the downstream discharge roller 17a is changed.

  Hereinafter, the configuration of the drive mechanism will be described in detail along the flow of operation.

  As shown in FIG. 18, when the drive motor 40a is reversed in the arrow direction, the downstream discharge roller 17a connected to the motor 40a by a gear and a belt rotates (forward rotation) in the sheet discharge direction (arrow direction in the figure). The sheet P is discharged and conveyed. At that time, the pressing force of the downstream discharge roller 17a and the movable discharge roller 17b is such that the protrusion 46b in the figure stops between the position of the solid line and the position of the broken line, and the rotation stop position and the swinging pressure spring The tensile force of 110 allows the pressure of the downstream discharge roller pair 17 to be increased or decreased. At this time, the current value of the drive motor 40 a driving the downstream discharge roller 17 a is controlled so as to be variable by the pressure applied by the downstream discharge roller pair 17.

  As shown in FIG. 19, when the drive motor 40b is rotated forward, the operating gear 46 is reversely rotated through the gear unit engaged with the motor 40b to rotate the position of the projection 46b to the position shown in the figure, thereby swinging. The force of the dynamic pressure spring 110 is increased, and the pressure of the downstream discharge roller pair 17 is increased. In this case, control is performed such that the current value of the drive motor 40a that drives the downstream discharge roller 17a is increased to convey the sheet P or the sheet bundle.

  Accordingly, when the operating gear 46 rotates in the direction of the arrow in FIG. 19, the strength of the swing pressurizing spring 110 can be freely changed depending on the rotation stop position of the operating gear 46. Further, as shown in FIG. 20, the protrusion 46 b comes into contact with the opening / closing arm 47 from below and pushes up the opening / closing arm 47, thereby pushing up the swing guide 20 in the direction of the arrow in FIG. The force is reduced and the drive of the drive motor 40b after detection is temporarily stopped by the swing opening detection sensor 55c, and the swing guide 20 is held in the open state.

  As described above, the holding position of the swing guide 20 is set to the height (level) of the sheet P in order to keep the contact area of the paddle 31 with the sheet P discharged onto the staple tray 12 constant. The rotation stop position of the operating gear 46 can be changed according to the change.

  Thereafter, when the stacking alignment of the sheets P on the staple tray 12 is completed and the drive motor 40b is rotated forward again, the swing guide 20 starts to descend. At this time, the drive motor 40a described above is rotated forward, and the downstream discharge roller 17a rotates by a predetermined amount (control) in the direction opposite to the sheet discharge direction to pull back and convey the sheet P. At the same time, control is performed so that the above-described swinging guide 20 is closed.

  By configuring as described above, a separate drive mechanism for driving the swing guide 20 and the downstream discharge roller 17a is provided, and by changing the pressure applied to the downstream discharge roller pair 17, sheet conveyance is stabilized and high-speed processing is performed. It can be performed. Further, by variably controlling the current value of the drive motor 40a, the size of the drive motor can be reduced, and a compact device with reduced current consumption can be achieved. Further, the rotation direction of the drive motor 40b at this time can be controlled by either forward rotation or reverse rotation.

[Oscillating guide closing operation]
As described above, the swing guide 20 is configured to be swingable about the swing shaft 20a. As shown in FIG. 20, when the operating gear 46 rotates in the direction of the arrow, the swing guide 20 has an open / close arm 47 in which a protrusion 46b provided on the operation gear 46 is attached to one side of the swing guide 20. Open by pushing up. When the operating gear 46 further rotates in the direction of the arrow in FIG. 20, the swing guide 20 begins to close. When the operating gear 46 further rotates, the projection 46b and the opening / closing arm 47 are disengaged, and the projection 46b opens and closes. Since the arm 47 is connected to the swinging pressure spring 110, after the engagement is released, the swinging pressure spring 110 starts to operate, and the moving discharge roller 17b attached to the swinging guide 20 is moved downstream. The contact pressure is increased by pressing against the discharge roller 17a.

  As a result, by increasing the pressure applied to the pair of downstream discharge rollers 17 described above, it is possible to discharge the aligned sheet bundle without disturbing the alignment of the bundle. Further, when discharging an unbound sheet bundle (a large number of sheets that are not stapled), by increasing the contact pressure of the downstream discharge roller pair 17, it is possible to discharge while suppressing slippage between the sheets. The consistency of the discharged sheet P can be improved. In addition, the time for discharging the sheet bundle is shortened, and high-speed processing becomes possible.

[Staple operation]
As described above, the sheet bundle stacked on the staple tray 12 is pinched by the downstream discharge roller pair 17 fixed to the discharge gear 43 and is bound by the stapler 13 in this state. Various combinations of the closing position are conceivable, but in the present embodiment, a mode in which the corner portion of the sheet P is bound at one place and a mode in which the corner portion of the sheet P is bound at two places along the rear end portion can be selected.

  When the stapler 13 is not at the predetermined staple position, it is necessary to move the stapler 13, but this may cause the sheet bundle stacked on the staple tray 12 to move. Therefore, when the stapler 13 is moved, the side guide 11 is pressed by the side guide 11 and is sandwiched between the reference guide 37. Thereby, there is no possibility that the alignment of the stacked sheets P is disturbed.

  However, if the binding operation is performed while being pressed by the side guide 11, the sheet guide 11 may bend in the width direction of the sheet bundle due to the pressing of the side guide 11, which may cause a stapling defect.

  Therefore, when performing the binding operation, as shown in FIG. 21, the pressure of the side guide 11 is released, the side guide 11 is separated from the side end portion of the sheet bundle, and is sandwiched only by the downstream discharge roller pair 17. The binding operation is performed in the state. Thereby, the bending of the sheet bundle due to the pressing of the side guide 11 can be released, and the stapling defect can be prevented.

[Sheet bundle discharge]
As described above, when the binding process is completed, the drive motor 40a rotates in the reverse direction, and the downstream discharge roller pair 17 rotates in the transport direction to discharge the bundle of sheets P onto the stack tray 18. At this time, the conveying force of the downstream discharge roller pair 17 is constant.

  For this reason, when the sheet bundle subjected to the binding process at one corner is discharged, the end face on the side where the binding process is not performed is easily displaced. This phenomenon depends on the size and the number of sheets P, and the smaller the size of the sheet P, the smaller the friction between the sheets, so that the deviation becomes remarkable.

  Further, conventionally, the control of discharging the sheet bundle by the downstream discharge roller pair 17 has been dealt with by individually controlling the drive motor 40a according to the sheet size and the number of sheets in order to reduce the deviation of the sheet bundle. By controlling in this way, the deviation of the sheet bundle was reduced, but it took a certain time to discharge the sheet bundle, and high-speed processing was difficult.

  Therefore, in the present embodiment, when the sheet bundle that has been bound at one place is discharged, the stack tray 18 is raised, and the stacking surface on the stack tray 18 is brought close to the downstream discharge roller pair 17. We are discharging. As a result, the resistance between the sheet bundle and the stacking surface on the stack tray 18 is reduced, and deviation is less likely to occur. Further, by increasing the pressure applied to the pair of downstream discharge rollers 17 and increasing the frictional force between the sheets, the sheet is less likely to be displaced during sheet discharge.

  As a result, even when a sheet bundle that has been bound in one place is discharged, the end face that is not bound is prevented from shifting to improve the stackability on the stack tray 18, and the sheet size or sheet bundle can be improved. It is possible to discharge at an equal speed regardless of the number of sheets.

  Further, by bringing the stack tray 18 close to the downstream discharge roller pair 17, there is an effect that the lowermost sheet P in the sheet bundle is prevented from buckling by eliminating the waist folding of the sheet bundle to be discharged.

[Load detection]
The level detection of the uppermost surface of the sheet P or sheet bundle stacked on the stack tray 18 is performed by a distance measuring sensor 54 provided above the swing guide 20 shown in FIG. The distance measuring sensor 54 has a light emitting unit that irradiates the sheet bundle with light rays such as infrared rays, and a light receiving unit that receives the light beam irregularly reflected by the sheet bundle, and detects the level by measuring the angle of the reflected light. Is to do.

  When the sheet P or the like is discharged onto the stack tray 18, the rear end of the sheet may be caught by the finisher unit C and may not settle down. If level detection is performed in such a state, accurate level detection may not be performed. Therefore, when the sheet P is discharged, the stack tray 18 temporarily moves downward and rises again, so that the sheet P settles on the stack tray 18.

  When detecting the level of the sheets P stacked on the stack tray 18, it is desirable that the distance measuring sensor 54 detects the level when the stack tray 18 is raised. However, in actuality, when the stack tray 18 is raised, the next sheet P has already been discharged. Therefore, the sheet P on the stack tray 18 cannot be seen due to the interruption.

  On the other hand, when level detection is performed when the vehicle descends, there is a possibility that the sheet P has not yet settled at that moment. In view of this, the level is detected twice or more at a predetermined interval, and when a value within the error range is continuously acquired, the detection result is acquired. This makes it possible to detect the actual level that has been determined, and to demonstrate the production capacity of the apparatus.

  Further, the position after the stack tray 18 is raised is controlled so that the height of the stacking surface is always constant based on the data obtained by the level detection (paper height control).

  Here, with reference to FIG. 22B, a configuration for recognizing the stacking amount of sheets P on the stack tray 18 (height of stacked sheets P) will be briefly described. The detailed configuration is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-48549. FIG. 22B is a perspective view of a main part showing a schematic configuration of the tray unit, the drive unit of the tray unit, and the position detection unit of the tray unit.

  In the present embodiment, the three stack trays 18 are fixed to the tray frame 57 to form a tray unit 58, and the three stack trays 18 move up and down integrally with respect to the finisher frame 59 of the finisher unit C. It can be moved up and down. The vertical movement of the tray unit 58, that is, the vertical movement of the stack tray 18 is transmitted to the rack portion 58 a provided in a part of the tray unit 58 by the pinion gear 225 by the forward / reverse drive of the stacker motor 209. The finisher frame 59 is configured to move up and down in the direction of the arrow in FIG.

  An encoder 226 is attached on the output shaft of the stacker motor 209, and a stacker motor clock sensor 227 is disposed at a position corresponding to the encoder 226. The stacker motor clock sensor 227 detects the pulse amount of the encoder 226 so as to know how many pulses the tray unit 58 has moved from the home position which is the initial position, that is, the amount of movement of the stack tray 18. . The home position of the stack tray 18 is detected by detecting the tray unit flag 57a provided at the lower part of the tray frame 57 by the tray home position sensor 228.

  After detecting the home position of the tray unit 58 based on a copy operation signal or the like (the tray home position sensor 228 detects the tray unit flag 57a), the predetermined stack tray 18 is moved to the downstream discharge roller pair based on the detection signal of the distance measuring sensor 54. The sheet P is positioned at a predetermined position with respect to 17 and the sheet P discharged by the downstream discharge roller pair 17 is received by the stack tray 18 described above.

  Further, in order to keep the position of the uppermost surface of the sheet P on the stack tray 18 at a predetermined amount from the downstream discharge roller pair 17, the stack tray 18 is lowered by a predetermined amount every time the sheets P (or sheet bundles) are stacked. It is supposed to be.

  Note that how many clocks the above-described tray unit 58 has moved from the home position, that is, the amount of movement of the stack tray 18 is recognized by the MPU (not shown) of the finisher unit C.

  From the above configuration, the position of the stack tray 18 and the position (level detection) of the uppermost surface of the sheet P on the stack tray 18 are determined, and the stacking amount of the sheets P stacked on the stack tray 18 (the stack sheet P (Height) can be recognized.

  As described above, the stacking amount of the sheets P stacked on the stack tray 18 is detected by detecting the position and level of the stack tray 18, and it is determined that the predetermined stacking amount determined by the processing mode and the sheet size is exceeded. When it is done, it recognizes that it is full (stack over).

  However, even when it is detected that the sheet is full, the sheet P on the stack tray 18 may not be settled due to curling or the state of catching at the rear end. For this reason, there is a case where it is determined that the apparatus is not fully loaded but the apparatus is stopped, and the productivity may be lowered.

  Therefore, in the present embodiment, it is confirmed that the top surface of the sheet P on the stack tray 18 has a height higher than a predetermined level, that is, the stacking amount of the sheets P on the stack tray 18 exceeds a predetermined amount. It is determined that the sheets P are full only after continuous detection, and the apparatus is stopped. More specifically, the stack tray 18 is moved up and down as described above, and the stacking amount of the sheets P on the stack tray 18 is detected for each operation (or after the operation is completed), and the stacking amount of the sheets P reaches a predetermined amount. It is determined that the sheet P is full only when it is continuously detected a plurality of times (three times in the present embodiment), and the apparatus is stopped.

  Further, in the present embodiment, as described above, the full detection of the sheets P is performed every time a predetermined number of sheets P (for example, five sheets) are discharged to the stack tray 18 described above.

  Thereby, it is possible to detect whether or not the stacking amount of the sheets P exceeds a predetermined amount after the curling of the sheets P generated on the stack tray 18 or the catching of the trailing end of the sheet is eliminated. Nevertheless, since it is determined that the sheet P is full only when it is continuously detected that the stacking amount of the sheet P exceeds the predetermined amount, the apparatus is stopped. Recognition can be prevented and sufficient productivity can be exhibited.

  FIG. 23 is a flowchart showing the system stop timing at the time of stack over.

  In the copying machine A, image formation is started, and sheets P are stacked on the stack tray 18 (S1). Every time a predetermined number (for example, five) of sheets P are stacked, it is detected whether or not the stack P is over (S2). If the stack is not over, the image forming and stacking operations are repeated. If a stack over is detected, it is determined whether or not a bundle of image formations has been completed (S3). Here, when the image formation for one bundle has not been completed, the image formation and the stacking operation are continued even if the stack is over. When one bundle of image formation is completed, the apparatus (system) is stopped (S4).

  By doing so, the image forming and stacking operations for one bundle are not interrupted, so that efficient image formation is possible.

  When the full sheet P is detected as described above and the apparatus is stopped, the user is prompted to remove the stacked sheets P (or sheet bundle) from the stack tray 18. .

1 is a longitudinal sectional view illustrating an overall configuration of an image forming apparatus to which the present invention can be applied. It is a longitudinal cross-sectional view which shows the whole structure of a sheet processing apparatus. It is a perspective view explaining the state of the sheet discharged by the offset process. FIG. 6 is a diagram for explaining a state of sheets discharged and sheets discharged by offset processing. FIG. 10 is a diagram illustrating a state in which a preceding sheet stays in a buffer path in the two-sheet discharge control. FIG. 10 is a diagram illustrating a state in which two sheets P are conveyed simultaneously in the two-sheet discharge control. It is a principal part longitudinal cross-sectional view which shows the position of the stack tray at the time of sheet | seat discharge. It is a figure explaining operation | movement of the rocking | fluctuation guide and paddle at the time of sheet | seat pullback. It is a figure explaining operation | movement of the rocking | fluctuation guide and paddle at the time of sheet | seat pullback. (A)-(g) is a figure explaining the paddle from which a shape differs, respectively. FIG. 6 is a diagram exemplifying paddle driving frequency, side guide moving speed, and alignment control according to sheet size. It is a figure which shows a stand-by position when a stapler is functioned as a rear-end stopper. It is a figure explaining the width | variety alignment state of the sheet | seat by a side guide. It is a figure explaining the width | variety alignment state of the sheet | seat by a side guide. It is a figure explaining operation | movement of the knurled belt at the time of sheet | seat width alignment by a side guide. (A), (b) is a figure explaining the knurled belt from which a shape differs, respectively. It is a figure explaining the width | variety alignment state of the sheet | seat by a side guide. It is a figure explaining operation | movement of the drive mechanism of a rocking | fluctuation guide and a downstream discharge roller pair. It is a figure explaining operation | movement of the drive mechanism of a rocking | fluctuation guide and a downstream discharge roller pair. It is explanatory drawing showing the operation state of the drive mechanism of a rocking | fluctuation guide and a downstream discharge roller pair. It is a figure explaining the binding operation by a stapler. (A) is a figure explaining the state which discharged | emitted the sheet | seat to the stack tray, (b) is a perspective view which shows the structure of the principal part of a tray unit. It is a flowchart explaining the control at the time of full load detection.

Explanation of symbols

3 Image forming section 9 Discharge roller (discharge means)
150 First conveying roller (conveying means)
152 CPU (first control means)
A Copying machine (image forming device main unit)
B Sheet processing device C Finisher unit D Stitcher unit P Sheet

Claims (6)

In a sheet processing apparatus including a conveying unit that conveys a sheet delivered from a discharging unit on the image forming apparatus main body side,
The leading edge of the sheet being discharged by the discharging means is temporarily stopped by the conveying means being stopped, a loop is formed between the conveying means and the discharging means, and then the conveying means is driven. ,
A sheet processing apparatus. Comprising first control means for controlling the operation of the conveying means;
The first control unit stops the leading edge of the sheet being discharged by the discharging unit at a nip portion of the conveying unit for a predetermined time by stopping the conveying unit, and then the image forming apparatus main body side Based on a signal from the second control means for controlling the discharging means, the driving of the conveying means is started.
The sheet processing apparatus according to claim 1. The first control unit changes a driving start timing of the transport unit based on a transport speed of the sheet delivered from the discharge unit;
The sheet processing apparatus according to claim 2. The first control unit changes the drive start timing of the transport unit based on the thickness of the sheet delivered from the discharge unit;
The sheet processing apparatus according to claim 2. The sheet processing apparatus has a plurality of sheet processing modes,
The first control unit changes a driving start timing of the conveying unit based on the sheet processing mode;
The sheet processing apparatus according to claim 2. Image forming apparatus comprising: an image forming apparatus main body having an image forming unit that forms an image on a sheet; and a discharge unit that discharges the sheet after image formation; and a sheet processing apparatus that performs processing on the sheet discharged from the discharge unit In the device
The sheet processing apparatus is the sheet processing apparatus according to any one of claims 1 to 5,
An image forming apparatus.

Images