JP2009242049A - Sheet processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device capable of stacking a highly accurately registered sheet bundle on a paper ejecting pan, without reducing productivity in subdivided paper ejection. <P>SOLUTION: This sheet processing device has an intermediate stacker loadable with a plurality of sheets, a sheet carrying-in means of the intermediate stacker, a registering means, a paper ejecting means, and a control means for controlling the carrying-in means, the registering means and the paper ejecting means. The control means controls the paper ejecting means so that the paper ejecting means ejects a second sheet bundle by stacking the second sheet bundle of adding a surplus sheet to the predetermined number of first sheet bundles of preceding to sheets of constituting a surplus on the intermediate stacker, when there is the surplus of subtracting integer times of the predetermined number of sheets from the number of sheets for constituting one group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus used for a copying machine, a printer, a facsimile, and the like.

  As this type of sheet processing apparatus, an apparatus that includes an intermediate stacker and discharges the sheets stacked on the intermediate stacker to a sheet discharge tray after performing various processes such as a binding process is widely used.

  This type of sheet processing apparatus is required to have a capability of aligning a large number of sheets well and discharging them to the discharge tray, that is, a capability of stacking sheets on the discharge tray in a form in which the edges are aligned. .

  Japanese Patent Application Laid-Open No. 2004-228561 proposes a sheet processing apparatus that stacks a plurality of sheets on an intermediate stacker and discharges them to a paper discharge tray after alignment on the intermediate stacker.

  In such a sheet processing apparatus, a number of sheets suitable for alignment on the intermediate stacker are stacked and aligned.

  Therefore, sheets are discharged from the intermediate stacker to the discharge tray in units of aligned sheet bundles. That is, the sub-sheet discharge is performed.

  In the sub-sheet discharge, the sub-sheet bundle is discharged in a state where the edges are highly aligned, and is discharged in sub-unit bundles, so that the alignment state is lost when discharged in a large bundle. Is well prevented.

  As a result, a sheet bundle that is well aligned as a whole is formed even when a large number of sheets are processed.

  When subdivided paper is ejected, the time required for ejecting the subdivided sheet bundle from the intermediate stacker prevents the subsequent sheet from being conveyed and stops the operation of the image forming apparatus, resulting in a decrease in productivity.

In order to avoid this, in Patent Document 1, conveyance control is performed in which the first sheet from the end of the subdivided sheet bundle is retained in the retention portion, and the retained sheet and the last sheet are collectively loaded into the intermediate stacker.
JP-A-11-130328

  In the subdivided paper discharge, the alignment between the sheets is good in the subdivided unit, but the alignment may be lowered between the subdivided sheet bundle.

  In the conveyance control of Patent Document 1, since the last two sheets are discharged together, the number of sheet bundles constituting the portion increases.

  For this reason, the chance of a decrease in consistency due to a decrease in consistency between sheet bundles increases, and the consistency of the entire sheets stacked on the paper discharge tray decreases.

  An object of the present invention is to solve such problems and provide a sheet processing apparatus that can stack sheets on a sheet discharge tray with high alignment and has high productivity.

The object is achieved by the following invention.
1.
Intermediate stacker capable of stacking a plurality of sheets, carry-in means for carrying sheets into the intermediate stacker, alignment means for aligning sheets on the intermediate stacker, paper discharge means for discharging sheets on the intermediate stacker, and ,
Control means for controlling the carry-in means, the alignment means and the paper discharge means;
The control means performs control for aligning the sheets carried in by the carry-in means by the aligning means, stacking the aligned sheets on the intermediate stacker, and discharging the accumulated sheet bundle by the paper discharge means. In the sheet processing apparatus,
When there is a remainder obtained by subtracting an integral multiple of the predetermined number from the number of sheets constituting one group, the control means adds the remainder to the predetermined number of first sheet bundles preceding the sheets constituting the remainder. 2. A sheet processing apparatus, comprising: stacking a second sheet bundle to which sheets have been added on the intermediate stacker; and controlling the paper discharge unit so that the second sheet bundle is discharged by the paper discharge unit.
2.
The sheet processing apparatus according to 1, wherein the remainder is one sheet.
3.
The carrying-in means has a staying part for staying sheets, and can carry in a plurality of sheets including a preceding staying sheet and a subsequent sheet to the intermediate stacker. The sheet processing apparatus according to 2.
4).
The sheet processing apparatus according to any one of 1 to 3, wherein the aligning unit can perform a shift process.
5.
The sheet processing apparatus according to any one of claims 1 to 4, further comprising a stapler that performs a binding process on a sheet on the intermediate stacker.

  In the present invention, when the sheets constituting the section are discharged by sub-sheet ejection, the remaining number of sheets obtained by subtracting an integral multiple of the predetermined number from the number of sheets constituting one group is added to the previous bundle. Discharge.

  Therefore, the number of subdivided sheet bundles is reduced rather than increased, and the chance of lowering the alignment is reduced, and the sheets can be stacked on the sheet discharge tray while maintaining high alignment as a whole.

  In addition, productivity is not reduced by the sub-sheet discharge.

Although the present invention will be described based on the illustrated embodiment, the present invention is not limited to the embodiment.
<Image forming apparatus>
FIG. 1 is an overall view of an image forming apparatus that includes an image forming apparatus main body GH and a post-processing apparatus FS and includes a sheet processing apparatus according to an embodiment of the present invention.

  The illustrated image forming apparatus main body GH includes an image reading unit 1, an image processing unit 2, an image writing unit 3, an image forming unit 4, a paper feed cassette 5, a paper feed unit 6, a fixing device 7, a paper discharge unit 8, an automatic unit. A double-sided copy paper feeding unit (ADU) 9 is provided.

  An automatic document feeder DF is mounted on the upper part of the image forming apparatus main body GH. A post-processing device FS is connected to the paper discharge unit 8 side on the left side of the image forming apparatus main body GH.

  The document placed on the document table of the automatic document feeder DF is conveyed in the direction of the arrow, and an image on one or both sides of the document is read by the optical system of the image reading unit 1, and is read by the CCD image sensor 1A.

  The analog signal photoelectrically converted by the CCD image sensor 1A is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing unit 2, and then sent to the image writing unit 3.

  At the time of image formation, output light is emitted from the semiconductor laser of the image writing unit 3, and the photosensitive drum 4A of the image forming unit 4 is irradiated to form a latent image. In the image forming unit 4, processes such as charging, exposure, development, transfer, separation, and cleaning are performed. The recording sheet S1 fed from the paper feed cassette 5 by the paper feed means 6 comes into contact with the photosensitive drum 4A in which the latent image is converted into a toner image by the development process, and the toner image is transferred by the transfer means 4B. The recording sheet S1 carrying the toner image is fixed by the fixing device 7 and sent from the paper discharge unit 8 to the post-processing device FS. In the case of double-sided copying, the recording sheet S1 that has undergone single-sided image processing is sent to the automatic double-sided copy paper feeding unit 9 by the conveyance path switching plate 8A, and image processing is performed again on the back side in the image forming unit 4 and fixed. The paper is discharged from the paper discharge unit 8.

  Next, a post-processing apparatus according to an embodiment of the present invention will be described with reference to FIG.

  The post-processing device FS includes a sheet carry-in unit 20, insertion paper feeding units 30a and 30b, and a plurality of post-processing units. The post-processing unit includes a punching processing unit 40, a folding processing unit 50, a staying unit 60, staplers 71 and 72, and a paper discharge unit 80.

  The insertion sheet feeding unit 30a is loaded with the insertion sheet S2, and the insertion sheet feeding unit 30b is loaded with another insertion sheet S3.

  The insertion sheets S2 and S3 are insertion sheets such as a cover sheet and an insert sheet that are inserted into the recording sheet S1 discharged from the image forming apparatus main body GH, and perform punching processing and folding processing similarly to the recording sheet S1. I can do it.

  The insertion sheets S2 and S3 sent out from the insertion sheet feeding sections 30a and 30b are conveyed to the sheet carry-in section 20 through a downward conveyance path (without reference numerals).

  The punching processing unit 40 is disposed in the sheet carry-in unit 20.

  In the following description, the recording sheet S1 and the insertion sheets S2 and S3 are collectively referred to as a sheet S.

  The folding processing unit 50 is disposed on a conveyance path H1 branched downward from the sheet carry-in unit 20.

  The staying unit 60 is disposed on the downstream side of the conveyance path H2 branched upward from the sheet carry-in unit 20, and includes conveyance paths H3, H4, and H5.

  In the staying unit 60, the subsequent sheet S stands by in the conveyance path H4 in the stapler 71 located on the downstream side in order to secure time for performing the binding process on the preceding sheet S.

  The conveyance path located on the downstream side of the conveyance path H2 is branched into a doubly curved conveyance path, and is divided into an inner conveyance path H4 and outer conveyance paths H3 and H5.

  A conveyance roller 21 is provided at the discharge port of the conveyance path H4 that forms an inner conveyance path that is branched from the conveyance path H2, and rotates when the first sheet S to be bound is conveyed. In a state in which the sheet is stopped, the leading edge of the sheet is received and is in a standby state in contact with the conveying roller 21.

  As described above, the sheet S conveyed on the conveyance path H2 waits with the leading end abutting against the conveyance roller 21, but the subsequent sheet S enters the conveyance path H3 from the conveyance path H2 and is conveyed to the conveyance roller. 21 is reached.

  From the conveying roller 21, the preceding sheet S and the succeeding sheet S are conveyed together and conveyed to the intermediate stacker 70.

  The conveyance path H3 is continuous with the conveyance path H2 downstream of the conveyance path H2, and the conveyance path H5 is continuous with the conveyance path H3.

  The conveyance path H3 is branched into a conveyance path H5 and a conveyance path H6.

  The conveyance path H <b> 6 forms a paper discharge path for discharging the sheet S to the fixed paper discharge tray 81.

  The fixed paper discharge tray 81 is disposed at a position that protrudes outside the post-processing device FS on the downstream side of the conveyance path H6 branched from the staying portion 60.

  As described above, the fixed paper discharge tray 81 is conveyed through the conveyance paths H2, H3, and H6 and accumulates the discharged sheets S.

  The paper discharge unit 80 includes a paper discharge roller 22 and discharges the sheet S to the lift paper discharge tray 82.

  The paper discharge roller 22 is composed of a pair of rollers. When the paper is not discharged, the pair of rollers are separated from each other.

  The sheet S conveyed by the conveyance roller 21 travels leftward between a pair of spaced apart rollers.

  When the trailing edge of the sheet S moves away from the conveying roller 21, the sheet S falls onto the intermediate stacker 70, slides down the inclined intermediate stacker 70, is received by the stopper 73, and stops at the intermediate stacker 70.

  When the set number of sheets S are stacked on the intermediate stacker 70, the stapler 71 operates to bind the sheets S.

  When the binding process is completed, the pair of rollers constituting the paper discharge roller 22 nips the bundle of sheets S and rotates in the paper discharge direction, and discharges the bundle of sheets S to the lift paper discharge tray 82.

  In the folding mode, the sheet S is conveyed downward along the conveyance path H <b> 1 from the sheet carry-in unit 20, and is subjected to intermediate folding or tri-folding processing in the folding processing unit 50 and is discharged to the lower paper discharge tray 83.

  In the saddle stitching mode, the sheet S is conveyed downward along the conveyance path H <b> 1 from the sheet carry-in unit 20, subjected to the saddle stitching process in the stapler 72, and subjected to the middle folding process in the folding processing unit 50, and then the lower discharge tray 83. To be discharged.

  Reference numeral 90 denotes alignment means for aligning the sheets S on the intermediate stacker 70.

There are the following four paths as the sheet S discharge path.
1) Sheet carry-in section 20 → conveyance path H2 → conveyance path H3 → conveyance path H6 → fixed discharge tray 81
2) Sheet carry-in section 20 → conveyance path H2 → conveyance paths H3, H4, H5 → intermediate stacker 70 → discharge section 80 → lifting / discharging tray 82
3) Sheet carry-in section 20 → conveyance path H2->H3->H5-> sheet discharge section 80 → lift sheet tray 82
4) Sheet carry-in unit 20 → conveying path H1 → folding processing unit 50 → lower sheet tray 83
The routes 1), 2) and 4) are as described above.

  The path 3) is selected when a large amount of image is formed without performing a binding process or a folding process.

  The sheet S is discharged to the elevating / discharging tray 82 without post-processing, and the elevating / discharging tray 82 is indicated by a chain line in the figure so that the uppermost surface of the discharged sheet S is always at a constant height. Move down to.

  Accordingly, it is possible to stack thousands of sheets on the elevating / discharging tray 82.

  FIG. 2 is a diagram illustrating the staying unit 60, the intermediate stacker 70, and the stapler 71.

  In the conveyance paths H2 to H6, the sheet S is conveyed by the conveyance rollers R and 21 including a pair of rollers as illustrated.

  The sheet S supplied from the transport roller H2 is sent to the transport path H3 or the transport path H4 by switching the switching gate GT.

  This switching is performed as follows.

  When the sheet S is continuously supplied, the previous sheet S is sent to the conveyance path H4. The sheet S sent to the conveyance path H4 stops when the leading edge reaches the conveyance roller 21. This stop control is performed based on the sheet leading edge detection signal of the sensor SE.

  The succeeding sheet S is sent to the conveyance path H3. After the sensor SE detects the leading edge of the succeeding sheet S, the transport roller of the transport path H is activated after a predetermined time and the preceding sheet S is transported, and the preceding sheet S and the succeeding sheet S overlap, and the intermediate stacker 70.

  Such sheet conveyance in which the two sheets S are conveyed in an overlapping manner is executed in order to earn time for discharging the sheet S from the intermediate stacker 70.

  In the paper discharge mode using the path 2), the sheet S conveyed by the conveyance roller 21 passes between a pair of rollers constituting the paper discharge roller 22.

  In the sheet discharge mode using the path 2), in the sheet conveyance stage by the conveyance roller 21, the pair of rollers constituting the sheet discharge roller 22 are separated from each other, and the sheet passes between the separated rollers to the upper left. .

  When the trailing edge of the sheet S passes through the conveying roller 21 and is discharged from the conveying roller 21, the sheet S falls on the intermediate stacker 70, and the trailing edge is received by the stopper 73 and stops.

  On the intermediate stacker 70, alignment processing is performed by the alignment means.

  In the staple mode, at the paper discharge stage after being stapled by the stapler 71, the pair of rollers constituting the paper discharge roller 22 contact and rotate, nip the sheet S, convey it, and discharge it to the lift paper discharge tray 82. To do.

  FIG. 3 is a diagram showing the matching means 90.

  The alignment members 90A and 90B arranged in parallel in the width direction perpendicular to the conveying direction reciprocate as shown by the arrow X to align the edge of the sheet.

  The alignment member 90A is fixed to a belt 92A, and the belt 92A is stretched around pulleys 93A and 94A and moves by driving of a motor 91A. Therefore, the alignment member 90A moves as indicated by the arrow X by driving the motor 91A.

  The alignment member 90B is fixed to the belt 92B. The belt 92B is stretched around pulleys 93B and 94B, and moves by driving the motor 91B. Therefore, the alignment member 90B moves as indicated by the arrow X by driving the motor 91B.

  FIG. 4 shows the sheet S after the shift process.

  The process shown in FIG. 4 is performed by the operation of the matching unit 90 as follows.

  The alignment member 90A is fixed at the alignment position, and the alignment member 90B is reciprocated by driving the motor 91B to align with the alignment member 90A of the sheet S.

  When the number of sheets reaches the alignment unit, the aligned sheet S bundle is discharged.

  Next, the alignment member 90B is fixed at the shift position, and the alignment member 90A is reciprocated by driving the motor 91A to align the sheet S with the alignment member 90B.

  As the alignment members 90A and 90B repeat the above-described operation, the shifted sheets S are stacked on the lifting / lowering tray 82 as shown in FIG.

  In the sheet processing using the path 2), the sheet S is conveyed in units of one or two sheets by the conveyance path H3, H5, the conveyance path H4, and the carry-in means having the conveyance roller 21 for discharging the sheet S to the intermediate stacker 70. It is carried into the intermediate stacker 70.

  Then, the bundle of sheets S is discharged from the intermediate stacker 70 to the elevating paper discharge tray 82 by the paper discharge unit configured by the paper discharge unit 80.

  Modes for transporting and discharging the paper via the path 2) include an Amd staple mode in which the stapler 71 performs a binding process and a Bmd non-staple mode.

  The Bmd non-staple mode using the path 2) further includes a B1md shift mode and a B2md non-shift mode.

  The Bmd non-staple mode includes a C1md subdivision mode and a C2md non-subdivision mode.

  The Amd staple mode and the B1md shift mode are executed by the operations of the stapler 71 and the alignment unit 90 described above.

  In the B2md non-shift mode, after the sheets S are stacked on the intermediate stacker 70, the sheets S are discharged to the lifting / discharging tray 82 by conveyance by the discharge rollers 22. In this case as well, the sheets are placed on the intermediate stacker 70. The alignment unit 90 operates each time the supply is performed, and the alignment process is performed.

  In the alignment processing in the B2md non-shift mode, alignment processing is performed in which the alignment members 90A and 90B are reciprocated simultaneously to align the edges of the sheet S on both sides.

  The C1md subdivision mode is a mode for accumulating on the elevating / discharging tray 82 with higher alignment accuracy.

  If the sheets S are discharged onto the elevating / discharging tray 82 without performing alignment processing, the edges of the stacked sheets are not aligned, which is inconvenient in handling the sheets after the post-processing by the post-processing device FS.

  Further, the method of aligning and discharging the sheets S one by one in the post-processing apparatus is not sufficient for the requirement for highly accurate alignment.

  In order to produce a highly accurate integrated sheet, it is necessary to create an aligned integrated sheet in the post-processing apparatus FS and to discharge it from the post-processing apparatus FS in an aligned state.

  However, if a large number of stacked sheets are discharged onto the lifting / lowering tray 82, the alignment is lost during discharge, and as a result, there is a problem that the alignment is lowered.

  Therefore, in a large number of image forming jobs, subdividing into a plurality of sheet units, aligning and stacking the subdivided sheets S, and discharging the subdivided sheets onto the lifting / discharging tray 82. Paper is done.

  That is, in the C1md subdivision mode, a predetermined number of sheets that are not related to the number of sheets per group are aligned and stacked on the intermediate stacker 70, and sheets are discharged from the intermediate stacker 70 to the lifting / lowering tray 82 in units of a predetermined number of sheets. The

  Next, control in the C1md subdivision mode will be described with reference to FIG.

  In the case where a group of N prints is created in one group, and the sheet S is discharged in the M-sheet subdivision mode, the discharge is performed by the basic operation shown in FIG.

  In FIG. 5A, 1 to M sheets are stacked on the intermediate stacker 70. In this stacking process, each time the sheet S is supplied onto the intermediate stacker 70, alignment processing by the alignment unit 90 is performed.

  When the M sheets S are accumulated on the intermediate stacker 70, the sheet is discharged to the lifting / discharging tray 82.

  Next, the sheet S between M + 1 and 2M sheets is accumulated on the intermediate stacker 70 and discharged.

  Thereafter, stacking and discharging are repeatedly performed, and M × k sheets S are discharged. A sheet indicated by a bold frame is the top sheet of the subdivision unit.

  Finally, the remaining number, that is, NM × k sheets are stacked on the intermediate stacker 70 and discharged.

  A unit of operation for discharging 1 to N sheets is executed T times to create a print of the T group.

  A group of sheets is composed of N sheets.

  As the group separation, there is a separation for each set corresponding to one set of originals, that is, N originals, or for each shift unit in the shift processing shown in FIG.

  When the sheet S is processed in the subdivision mode shown in FIG. 5A, there is a problem that a waiting time is generated between the groups and productivity is lowered.

  This problem will be described with reference to FIG.

  FIG. 5B shows a case in which 5 sheets are divided into small units, and a group of 6 sheets is discharged.

  When five sheets are stacked on the intermediate stacker 70 and discharged, one is left.

  The inter-sheet time t1 for supplying one sheet to the intermediate stacker 70 and discharging it after alignment processing is longer than the inter-sheet time t2 when the sheets S are continuously supplied onto the intermediate stacker 70.

  The first sheet S in the second group needs to be supplied onto the intermediate stacker 70 after the elapse of the inter-sheet time t1, and t1-t2 becomes a waiting time, and the image forming apparatus main body GH operates for t1-t2. Will stop.

  Note that, for example, when the remainder of dividing the number of group constituents by the subdivision unit is 2 or more such that 5 sheets are subdivided units and one group is composed of 7 sheets, the conveyance path that is the sheet S1 is a staying portion. The waiting time is eliminated by staying in H4.

  The waiting time t1-t2 is removed by the conveyance control described below.

  The conveyance control for removing the waiting time will be described by taking, as an example, the case of printing in a group of 6 sheets with 5 sheets as a subdivision unit.

  Six sheets S obtained by adding the remaining one sheet to five subdivision units are stacked on the intermediate stacker 70.

  FIG. 5C shows such conveyance control.

  1 to 6 sheets are supplied and accumulated on the intermediate stacker 70 at the inter-sheet time t2.

  The first sheet S of the second group, that is, the seventh sheet S stays in the transport path H4.

  The second sheet S of the second group, that is, the eighth sheet S overlaps with the seventh sheet S and is supplied to the intermediate stacker 70.

  Between the supply of the sixth sheet S and the supply of the seventh and eighth sheets S, an inter-sheet time t3 is secured. Since the inter-sheet time t3 is the sum of the conveyance times of the two sheets S as shown in the figure, the sheet bundle composed of the first group of sheets S and the sixth sheet S is discharged from the intermediate stacker 70. Long enough for the time required.

  Therefore, on the image forming apparatus main body GH side, the seventh and eighth sheets S can be transported at a normal sheet interval and sent to the post-processing apparatus FS. Thus, smooth processing can be performed on the sheet S fed in.

  In FIG. 5 (c), when the last one of the group is left from the subdivision unit, the remaining one is added to the previous subdivision unit, aligned, accumulated, and discharged. Even in the case of two or more sheets, the remainder of two or more sheets may be added to the previous subdivision unit.

  However, the remaining number added to the previous subdivision unit should be as small as possible, and it is most preferable to add one sheet to the previous sheet bundle.

  In this way, the paper can be discharged by the subdivision process without increasing the interval between the sheets S.

  As a result, highly accurate alignment processing is possible without reducing productivity.

  Next, the conveyance / discharge control of the sheet for performing the divided discharge described above will be described with reference to FIGS. FIG. 6 is a block diagram of the control system, and FIGS. 7 and 8 are flowcharts of stay control and stack control.

  CR is a control means for performing control in the post-processing device FS.

  The control means CR is provided in the image forming apparatus main body GH, and based on a command from the main control means MCR that controls the entire image forming apparatus and a sheet detection signal of the sensor SE provided in the conveyance path H2, the motor M, The switching gate GT, the alignment unit 90, and the paper discharge unit HM are controlled.

  By this control, the sequence described below is executed.

  The motor M is a motor that drives a roller R provided in the transport path H2.

  In step ST1, it is determined whether the process is performed by the intermediate stacker 70 or not. This determination is made based on post-processing mode information transmitted from the main control means MCR.

  If the process is not performed in the intermediate stacker 70, that is. In the mode in which the sheet S is discharged to the fixed discharge tray 81 or the mode in which the sheet is discharged to the lower discharge tray 83 (No in ST1), the process proceeds to the sub-tray discharge or saddle stitch discharge flow (ST30).

  In the case of the processing in the intermediate stacker 70 (Yes in ST1), it is determined whether or not the sheet is a staying processing target (ST2).

  If it is not the staying process (No in ST2), the process proceeds to step ST31 and the non-staying process is performed.

  In ST31, the sheet S is conveyed to the conveyance roller 21 via the conveyance paths H3 and H5.

  In the case of the staying process (Yes in ST2), the counter in the control means CR counts the number of sheets in the group.

  This number counting is performed based on the sheet detection signal of the sensor SE.

  In the illustrated example in which the subdivided sheet bundle includes M sheets, it is determined in step ST4 whether or not the counted number is an integral multiple of M (M × k) +1.

  If the counted number is not M × k + 1 (No in ST4, stack processing (described later)), the process proceeds.

  If the counted number is M × k + 1 (Yes in ST4), it is determined in step ST5 whether the paper is non-last paper. The last paper is the last paper of each group. In FIG. 5A, the Nth sheet, which is the number of groups, is the last sheet, and in FIGS. 5B and 5C, the sixth sheet is the last sheet.

  The determination regarding the last paper is made based on the information transmitted from the main control means MCR.

  The main control means MCR adds the information on the last sheet to the post-processing command and transmits it to the control means CR.

  In the case of last paper (No in ST5), the process proceeds to stack processing.

  If it is not the last paper (Yes in ST5), the motor M is activated and the roller R in the transport path H4 rotates (ST6).

  Next, the switching gate G is operated to guide the sheet to the conveyance path H4 (ST7).

  Next, the motor M is stopped, and the sheet is stopped in a state where the leading end is nipped by the conveying roller 21 (ST8).

  Next, the motor M is restarted to convey the sheet, and the sheet is conveyed to the intermediate stacker 70 (ST9).

  The process proceeds from ST4 No, ST5 No, and ST9 to stack processing.

  In the stack process of FIG. 8, the matching process is first executed (ST10).

  The alignment process is based on the reciprocating operation of the alignment members 90A and 90B and the rotation of the alignment brush 96, and alignment in the transport direction and the width direction is performed.

  The matching process includes an offset process.

  In a succeeding step ST11, it is determined whether or not it is non-last.

  If it is not non-last paper (No in ST11), that is, if it is last paper, in step ST32, a paper discharge process for conveying a bundle of sheets to the paper discharge unit 80 is performed, and the process ends.

  In the case of non-lasting paper in the determination in step ST1, in step ST12, the counter CT counts the number of sheets in the group, and in step ST13, it is determined whether or not the counted number is an integral multiple of the subdivision unit M.

  If it is not an integral multiple of M, the stack process ends.

  That is, the sheet conveyance in the M subdivision units is continued, and the sheet stacking on the intermediate stacker 70 is continued.

  If it is an integer multiple of M in step ST13 (Yes in ST13), it is determined in step ST14 whether or not the sheet is immediately before the last group.

  No in step ST14 indicates that the remainder of the bundle of subdivided sheets, that is, an integral multiple of M, and the number obtained by subtracting M × k from the group constituting number N is not 1, that is, 0, 2, 3, 4,・ ・ This is the case.

  In the case of No in step ST14, the paper discharge process ST32 for conveying the sheet bundle to the paper discharge unit 80 is executed and the process ends.

  In the case of Yes in step ST14, if M × k + 1 = N, that is, if the remainder 1 that is an integral multiple of M is the last sheet of the group, the stack process ends.

  When the stack process is completed in Yes in ST14, the sheet loaded into the intermediate stacker 70 is the final sheet of the group.

  In the stack processing of FIG. 8 relating to the final sheet, the determination of No is made in step ST11.

  The state determined as Yes in step ST14 is a state in which M sheets are stacked in an aligned state on the intermediate stacker 70, so that one sheet aligned in ST10 is added thereto, and step ST32 is performed. Then, M + 1 sheets are discharged.

1 is an overall view of an image forming apparatus having a sheet processing apparatus according to an embodiment of the present invention. It is a figure which shows the stay part 60, the intermediate stacker 70, and the stapler 71. It is a figure which shows the alignment means 90. FIG. The sheet S after the shift process is shown. It is a figure explaining the time between sheets. It is a block diagram of a control system. It is a flowchart of stay control and stack control. It is a flowchart of stay control and stack control.

Explanation of symbols

GH image forming apparatus main body FS post-processing apparatus 60 staying part 70 intermediate stacker 71 stapler 73 stopper 80 paper discharge part 90 aligning means CR control means

Claims (5)

Intermediate stacker capable of stacking a plurality of sheets, carry-in means for carrying sheets into the intermediate stacker, alignment means for aligning sheets on the intermediate stacker, paper discharge means for discharging sheets on the intermediate stacker, and ,
Control means for controlling the carry-in means, the alignment means and the paper discharge means;
The control means performs control for aligning the sheets carried in by the carry-in means by the aligning means, stacking the aligned sheets on the intermediate stacker, and discharging the accumulated sheet bundle by the paper discharge means. In the sheet processing apparatus,
When there is a remainder obtained by subtracting an integer multiple of the predetermined number from the number of sheets constituting one group, the control means adds the remainder to the predetermined number of first sheet bundles preceding the sheets constituting the remainder. 2. A sheet processing apparatus, comprising: stacking a second sheet bundle to which a sheet is added on the intermediate stacker; and controlling the paper discharge unit so that the second sheet bundle is discharged by the paper discharge unit. The sheet processing apparatus according to claim 1, wherein the remainder is one sheet. The said carrying-in means has a retention part which retains a sheet | seat, and can carry in to the said intermediate | middle stacker collectively the several sheet | seat which match | combined the sheet | seat which precedes the preceding retention sheet | seat. The sheet processing apparatus according to claim 2. The sheet processing apparatus according to claim 1, wherein the aligning unit can perform a shift process. The sheet processing apparatus according to claim 1, further comprising a stapler that performs a binding process on a sheet on the intermediate stacker.

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