JP2013001544A - Sheet processor and sheet processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To superpose reproducibly the apical portion of unfolded sheet material and the apical portion of folded sheet material by devising methods of superposition of sheet material at a standby position.SOLUTION: This processor includes an apical portion detecting sensor 12 detecting the intake of both a sheet Pi and a Z-folded sheet P, a rear end detecting sensor 13, a switchback conveying unit 20 to which the detected sheet Pi is taken in to convey toward a predetermined superposed position and then conveys inversely from the superposed position to the predetermined standby position, a standby position conveyance unit 40 conveying the sheet Pi thus conveyed inversely to the standby position from the standby position toward the superposed position, and a control unit 50 entering length information of the Z-folded sheet P in the conveying direction, determining a start timing of conveying of the sheet Pi from the standby position toward the superposed position based on length information concerned, and setting the conveyance start timing after the decision to the standby position conveyance unit 40.

Description

  The present invention provides an image forming system constructed by combining a printer for color, black and white, a copying machine, a multi-function machine, a finisher, and the like, with a plurality of sheet leading ends after image formation and a predetermined shape. The present invention relates to a sheet processing apparatus and a sheet processing method suitable for being applied to a sheet stacking and sending apparatus that superimposes and sends folded folded sheets.

  In recent years, an image forming system in which an image forming apparatus that forms an image based on image information and a post-processing apparatus that performs post-processing on a recording sheet after image formation has been often constructed. The post-processing apparatus includes a sheet processing apparatus that superimposes and feeds a plurality of sheet materials, a punch processing apparatus that opens punch holes in a bundle of sheets on which a plurality of sheet materials are superimposed, and a sheet on which a plurality of sheet materials are superimposed. Staple processing devices that apply staples to a bundle are used. A model in which these device functions are mounted in one post-processing device is also manufactured.

  In the sheet processing apparatus, the leading ends of a plurality of sheets after image formation and a sheet that is folded into a predetermined shape, for example, a Z shape or a W (M) shape (hereinafter referred to as a folded sheet). Some are sent in a superimposed manner. The sheet processing apparatus includes a type for mounting a folding processing mechanism and a type for mounting a folding processing means.

  With regard to this type of sheet processing apparatus, the sheet processing apparatus disclosed in Patent Document 1 includes a stacking unit, an alignment unit, a control unit, a detection unit, and a measurement unit. The stacking unit loads the sheet material that has been loaded. The aligning means abuts against the end of the sheet material stacked on the stacking means and aligns the conveying direction of the sheet material. The control unit changes the alignment position of the alignment unit according to information obtained from the detection unit and the measurement unit and length information in the conveyance direction of the folded folded sheet material.

  When the detecting means detects the passage of the leading edge and the trailing edge when conveying the folded sheet material, the measuring means measures the length of the folded sheet material based on the detection result of the detecting means. Based on this assumption, the control unit changes the alignment position of the alignment unit based on the length information of the folded sheet material obtained from the measurement unit. If the sheet processing apparatus is configured in this way, the end portions of the folded sheet material can be reliably aligned, so that the alignment accuracy can be improved.

  Further, according to the post-processing system disclosed in Patent Document 2, the first and second transport paths, pre-stacking means, stapling means, and control means are provided. The first conveyance path conveys the sheet material to the prestack means at a predetermined position. The pre-stacking unit is disposed on the first conveyance path and stacks the sheet material conveyed on the first conveyance path. The stapling means is disposed on the downstream side of the pre-stacking means, and performs a predetermined type of stapling process on the sheet material conveyed through the first conveyance path. The second conveyance path is disposed downstream of the prestacking unit at a position where it merges with the first conveyance path, and conveys the folded sheet material that has been subjected to folding processing in a predetermined format by the folding unit to the prestacking unit.

  The control unit conveys the sheet material following the folded sheet material in advance through the first conveyance path and stacks the sheet material on the prestacking unit. Based on this premise, at the time of sheet conveyance control, the control means releases the stack by the pre-stack means at a timing at which both the folded sheet material and the subsequent sheet material can be conveyed, and the subsequent sheet material and the folded sheet material are stapled. To be transported to. When the post-processing system is configured in this way, the productivity caused by waiting the sheet material to be conveyed next by the pre-stacking unit between the sheet folding time and the time for conveying the folded sheet material to the stapling unit. It can prevent the decrease.

JP 2010-215397 A (page 10 FIG. 5) Japanese Patent Laying-Open No. 2009-292540 (FIG. 1 on page 6)

  Incidentally, the sheet processing apparatus according to the conventional example has the following problems.

  i. According to the sheet processing apparatus of Patent Document 1, a configuration is adopted in which the alignment position of the alignment means is changed based on the length information of the folded sheet material. However, when trying to adopt a configuration in which one or two or more bundles of sheet materials placed in a predetermined position on a folded sheet material in the middle of conveyance are sent in an overlapping manner, the folded sheet material In the configuration in which the alignment position is changed based on the length information, the conveyance start timing of one or two or more sheets at the standby position, the conveyance speed thereof, and the like are not included in the control target. There is a problem that the front end portion of the folded sheet material and the front end portion of the sheet material cannot be overlapped with good reproducibility.

  ii. According to the post-processing system of Patent Document 2, the control unit releases the stack by the prestack unit at a timing at which both the folded sheet material and the subsequent sheet material can be conveyed during sheet conveyance, and the subsequent sheet material and the folded sheet A configuration is employed in which the material is conveyed to the stapling means.

  For this reason, there exists a state in which the folded sheet material and the subsequent sheet material are temporarily stopped by the prestacking means. Therefore, the processing time from the time when the sheet is taken in to the time when the sheet superposition is completed is longer than when the subsequent sheet material is superposed on the folded sheet material that is being conveyed. Thereby, there exists a problem that productivity in the said post-processing system falls.

  iii. In general, when a folded sheet material is conveyed, the folded sheet material is usually conveyed with the folded portion at the top. The reason for this is that when the folded sheet material passes through the conveying roller, if the folded portion is at the rear end, the sheet material of the unfolded portion smoothly passes through the conveying roller. However, when the folded portion passes the transport roller, the folding portion opens and a phenomenon of turning up occurs (there is a possibility). For the reasons described above, the Z-folded sheet material cannot be put on standby by a prestack unit or the like having a reverse conveyance mechanism.

  iv. In addition, since the folded portion of the folded sheet material has a bulge compared to the unfolded sheet material, the sheet detection apparatus having directivity causes variations in the sheet detection signal when detecting the leading edge. Therefore, there is a problem that the front end portion of the sheet material (hereinafter also referred to as a non-folded sheet material) and the front end portion of the folded sheet material cannot be overlapped with high reproducibility.

  Therefore, the present invention solves the above-described problems, and devise a method for superimposing the sheet material at the standby position to superimpose the leading end portion of the non-folded sheet material and the leading end portion of the folded sheet material with good reproducibility. An object of the present invention is to provide a sheet processing apparatus and a sheet processing method which can be performed.

  In order to solve the above problem, a sheet processing apparatus according to claim 1 is a sheet processing apparatus according to claim 1, wherein one sheet that has not been folded, or a non-folded sheet material that is a stack of two or more sheets, and one folded sheet that has been folded. A sheet processing apparatus that superimposes and feeds a sheet material at a predetermined overlapping position, the sheet detecting means for detecting the unfolded sheet material and the intake of the folded sheet material, and detected by the sheet detecting means A first sheet conveying unit that takes in the non-folded sheet material and conveys the unfolded sheet material toward a predetermined overlapping position, and then reversely conveys the unfolded sheet material from the overlapping position to a predetermined standby position; and the first sheet A second sheet conveying unit configured to convey the non-folded sheet material reversely conveyed to the standby position by the conveying unit from the standby position toward the overlapping position; The length information in the conveyance direction of the sheet material is input, and the conveyance start timing of the non-folded sheet material conveyed toward the overlapping position is determined based on the length information of the folded sheet material. And a control unit that sets the conveyance start timing of the non-folded sheet material in the second sheet conveyance unit.

  According to the sheet processing apparatus of the first aspect, one sheet that has not been folded, or a non-folded sheet material that is a stack of two or more sheets, and a single folded sheet material that has been folded are stacked in a predetermined manner. When the sheet detection unit detects the intake of the non-folded sheet material and the folded sheet material when the sheets are overlapped and sent out at the alignment position, at least the non-folded sheet material is detected by the sheet detection unit by the sheet detection unit. Is transported toward a predetermined overlapping position, and then reversely transported from the overlapping position to a predetermined standby position.

  The control unit inputs length information in the conveyance direction of the folded sheet material, and determines the conveyance start timing of the non-folded sheet material conveyed from the standby position toward the overlapping position based on the length information of the folded sheet material Then, the determined conveyance start timing of the non-folded sheet material is set in the second sheet conveyance unit. On the premise of this, the non-folded sheet material reversely conveyed by the first sheet conveying unit to the standby position by the first sheet conveying unit is moved from the standby position to the overlapping position based on the determined conveyance speed. The sheet is conveyed (conveyance control of the sheet material at the standby position).

  By this conveyance control, even if the folded sheet material is taken in at any conveyance timing (conveying speed), in the middle of conveyance, the leading end portion of the non-folded sheet material conveyed from the standby position toward the overlapping position; It is possible to superimpose the leading end portion of the folded sheet material taken last after the non-folded sheet material with good reproducibility (without inferiority).

  A sheet processing apparatus according to a second aspect of the present invention is the sheet processing apparatus according to the first aspect, wherein the sheet detection means for outputting the sheet detection information to the control unit is provided at a predetermined position of the first sheet conveying unit. A first sheet detection unit that detects the leading edge of the folded sheet material, and a sheet conveyance path that is separated from the first sheet detection unit by a predetermined length, and at least detects the rear end of the folded sheet material. And a second sheet detecting unit.

  The sheet processing apparatus according to a third aspect is the sheet processing apparatus according to the second aspect, wherein the control unit inputs rear end detection information obtained by detecting a rear end of the folded sheet material from the second sheet detection unit, and Time information from the time when the trailing edge of the folded sheet material is detected based on the trailing edge detection information of the sheet material to the conveyance start timing of the non-folded sheet material is calculated, and the time information and the length information of the folded sheet material The non-folded sheet material and the folded sheet are determined while the conveyance speed of the non-folded sheet material is fixed based on the determined conveyance start timing. It is characterized by superposing materials.

  A sheet processing apparatus according to a fourth aspect of the present invention is the sheet processing apparatus according to the second aspect, wherein when the control unit performs sheet conveyance control based on the first and second sheet detection units, the first sheet detection unit is When the leading edge of the folded sheet material is roughly detected, the non-folded sheet material starts to be conveyed from the standby position to the overlapping position at a predetermined conveyance speed. When the rear end of the sheet material is detected, the conveyance speed of the non-folded sheet material is changed, and when the sheet conveyance control is performed based on the second sheet detection unit, the second sheet detection unit is the folded sheet. When the leading end of the material is roughly detected, the non-folded sheet material is started to be transported from the standby position to the overlapping position at a predetermined transport speed, and after the transport is started, the second sheet detecting unit detects the folded sheet material. The rear end of With knowledge, it is characterized in changing the conveying speed of the non-folded sheet material.

  The sheet processing method according to claim 5, wherein the sheet processing apparatus that superimposes and sends the unfolded sheet material that has not been folded and the folded sheet material that has been folded at a predetermined overlapping position, A process of superposing one sheet or two or more sheets and waiting at a predetermined standby position; conveying the non-folded sheet material from the standby position toward the overlapping position; and taking in the folded sheet material And detecting the trailing edge of the folded sheet material taken into the overlapping position at a predetermined position when executing the process of superimposing the leading edge of the non-folded sheet material and the leading edge of the folded sheet material. The trailing edge detection information obtained by the trailing edge detection of the folded sheet material is input, and the length information in the conveyance direction of the folded sheet material is input, and the trailing edge detection information of the folded sheet material is input. Time information from the time when the rear end of the folded sheet material is detected to the conveyance start timing of the non-folded sheet material is calculated, and the non-folded sheet is calculated based on the time information and the length information of the folded sheet material. Determining the conveyance start timing of the material, and superimposing the non-folded sheet material and the folded sheet material with the conveyance speed of the non-folded sheet material fixed based on the conveyance start timing determined here It is a feature.

  The sheet processing method according to claim 6, wherein the sheet processing apparatus that superimposes and feeds the unfolded sheet material that has not been folded and the folded sheet material that has been folded at a predetermined overlapping position, A process of superposing one sheet or two or more sheets and waiting at a predetermined standby position; conveying the non-folded sheet material from the standby position toward the overlapping position; and taking in the folded sheet material When the front end of the folded sheet material is detected when the front end portion of the non-folded sheet material and the front end portion of the folded sheet material are overlapped, When the sheet material starts to be conveyed from the standby position to the overlapping position at a predetermined conveyance speed, and the rear end of the folded sheet material is detected after the conveyance starts, the non-folded sheet material It is characterized in changing the conveying speed.

  According to the sheet processing apparatus according to claim 1, the sheet processing apparatus includes a control unit that determines the conveyance start timing of the non-folded sheet material conveyed from the standby position toward the overlapping position based on the length information of the folded sheet material, The control unit sets the determined conveyance start timing of the non-folded sheet material in the second sheet conveyance unit.

  With this configuration, even when the folded sheet material is taken in at any conveyance timing (conveying speed), the leading end portion of the non-folded sheet material conveyed from the standby position toward the overlapping position in the middle of conveyance, It is possible to superimpose the folded sheet material and the leading end portion of the folded sheet material that is taken in last with good reproducibility (without inferiority).

  Thereby, at the time of post-processing work such as a binding process, the second sheet conveying unit can be put on standby in a state where a bundle of non-folded sheet materials to be post-processed next is overlapped, and productivity in the sheet processing apparatus can be increased. Can be improved.

  According to the sheet processing apparatus of the second aspect, since the sheet detection unit includes the first and second sheet detection units, the sheet detection unit conveys from the standby position toward the overlapping position based on the leading edge detection information of the non-folded sheet material. The conveyance start timing of the non-folded sheet material can be determined. Further, the conveyance speed of the non-folded sheet material conveyed from the standby position toward the overlapping position can be changed based on the trailing edge detection information of the folded sheet material.

  According to the sheet processing apparatus according to claim 3 and the sheet processing method according to claim 5, the non-folded sheet material conveyed from the standby position toward the overlapping position based on the trailing edge detection information of the folded sheet material. Since the conveyance start timing can be determined, the leading edge of the non-folded sheet material that is conveyed from the standby position toward the stacking position during conveyance, regardless of the conveyance timing (conveyance speed) of the folded sheet material And the leading end of the folded sheet material that is finally taken in after the non-folded sheet material can be superimposed with good reproducibility.

  According to the sheet processing apparatus according to claim 4 and the sheet processing method according to claim 6, when the leading end of the folded sheet material is roughly detected, the non-folded sheet material is directed from the standby position to the overlapping position at a predetermined conveyance speed. When the second sheet detector detects the trailing edge of the folded sheet material after the start of conveyance, the conveyance speed of the non-folded sheet material is changed, so that the sheet is conveyed from the standby position toward the overlapping position. The leading end portion of the non-folded sheet material and the leading end portion of the folded sheet material that is finally taken in after the non-folded sheet material can be superimposed with good reproducibility.

It is a block diagram which shows the structural example of the sheet | seat overlap sending apparatus 100 as embodiment which concerns on this invention. (A) And (B) is explanatory drawing which shows the operation example (the 1) at the time of multiple sheet superposition mode. (A) And (B) is explanatory drawing which shows the operation example (the 2) at the time of multi-sheet overlap mode. It is explanatory drawing which shows the operation example (the 3) at the time of multiple sheets overlap mode. (A) And (B) is explanatory drawing which shows the operation example (the 1) at the time of Z folding mode. It is explanatory drawing which shows the operation example (the 2) at the time of Z folding mode. (A)-(C) is a time chart which shows the example of sheet detection as the 1st example at the time of the multi-stack mode and the Z folding mode. It is a graph showing an example of conveyance of a sheet Pi at the standby position. 3 is a flowchart illustrating a control example of the sheet stacking and sending apparatus 100 as the first embodiment. (A)-(C) is a time chart which shows the example of sheet detection as the 2nd example at the time of the multi-sheet superposition mode and the Z folding mode. It is a graph showing an example of conveyance of a sheet Pi at the standby position. It is a flowchart which shows the example of control of the sheet | seat overlap sending device 100 as a 2nd Example.

  Hereinafter, a sheet processing apparatus and a sheet processing method according to embodiments of the present invention will be described with reference to the drawings. 1 constitutes an example of a sheet processing apparatus. One sheet that has not been subjected to Z-folding processing, or a non-Z-folded sheet material in which two or more sheets are stacked (hereinafter simply referred to as sheet Pi (i = 1 to n)) and a single folded sheet material (hereinafter referred to as a Z-folded sheet Pz) that has been subjected to the Z-folding process.

  The sheet overlap delivery device 100 includes a take-in roller 11, a leading edge detection sensor 12, a trailing edge detection sensor 13, a switchback conveyance unit 20, a branching unit 30, a standby position conveyance unit 40, and a control unit 50. The sheet material includes plain paper, thick paper, coated paper, thin paper, film, and the like, and also includes a sheet P1 and a Z-fold sheet Pz having different paper types and basis weights. The bundled sheet P1 and the Z-folded sheet Pz are also referred to as a sheet bundle (sheet bundle).

  The take-in roller 11 is provided on the upstream side of the sheet overlap delivery device 100. Here, the upstream side is a paper feeding side for taking in a sheet material, for example, a side on which a sheet P1 recorded from the image forming apparatus, a Z-folded sheet Pz subjected to Z-folding from the Z-folding mechanism, or the like is fed. is there. The downstream side is a paper discharge side for sending out a sheet bundle in which sheets Pi, Z-folded sheets Pz, and the like are overlapped. For example, the sheet bundle is on the side of a post-processing device on which post-processing such as punching or stapling is performed. is there. The take-in roller 11 also serves as a drive source for the switchback transport unit 20. Of course, a drive source may be provided separately from the switchback transport unit 20.

  The leading edge detection sensor 12, the trailing edge detection sensor 13, and the like constitute an example of a sheet detection unit, and output sheet detection information to the control unit 50. The leading edge detection sensor 12 constitutes an example of a first sheet detection unit, and is disposed at a predetermined position of the switchback conveying unit 20, for example, upstream of the take-in roller 11, and detects at least the front end (take-in) of the sheet Pi. Then, the leading edge detection signal S12 (sheet detection information) is generated. For example, when the leading edge detection signal S12 detects the leading edge of the sheet Pi, the leading edge detection signal S12 falls from the high level to the low level (ON → OFF).

  Regarding the leading edge detection sensor 12, the Z-folded sheet Pz is generally conveyed with the Z-folded sheet Pz at the head, so that the leading edge cannot be detected accurately. The Z-folded part is transported at the top when the non-Z-folded part on the opposite side of the Z-folded part is transported at the top, the folded part opens and wraps around the transport roller, etc. This is because it often causes a jam.

  The rear end detection sensor 13 constitutes an example of a second sheet detection unit and is arranged on the upstream side of the front end detection sensor 12. For example, the trailing edge detection sensor 13 performs Z-folding from the position where the leading edge detection sensor 12 is disposed in order to control the conveyance speed of a sheet Pi (hereinafter also referred to as a standby sheet) waiting at a standby position with a margin. The sheet Pz is disposed at a position farther upstream than the maximum sheet length of the sheet Pz.

  The trailing edge detection sensor 13 detects at least the trailing edge of the Z-folded sheet Pz and generates a trailing edge detection signal S13 (sheet detection information). For example, when the rear end detection signal S13 detects the rear end of the Z-folded sheet Pz, the rear end detection signal S13 falls from the high level to the low level (ON → OFF). Of course, an output circuit may be inverted by connecting an inverter circuit to the output stage of the leading edge detection sensor 12 or the trailing edge detection sensor 13. A transmissive or reflective optical sensor is used for the front end detection sensor 12 or the rear end detection sensor 13.

  The switchback conveyance unit 20 constitutes an example of a first sheet conveyance unit, and is disposed on the downstream side of the take-in roller 11. The switchback conveyance unit 20 takes in the sheet Pi detected by the leading edge detection sensor 12, conveys the sheet Pi toward a predetermined overlapping position, and then reversely conveys the sheet Pi from the overlapping position to a predetermined standby position. The sheet Pi has a function of through-passing to the downstream side without being reversely conveyed.

  In this example, the through-pass function is used to superimpose the Z-folded sheet Pz on the standby sheet Pi and discharge it to the downstream side as it is without being reversely conveyed to the standby position. If the Z-folded sheet Pz is reversely conveyed to the standby position like the other sheets Pi, a jam may occur due to the above-described reason. Therefore, the Z-folded sheet Pz is always superimposed on the end of the other sheet i.

  The switchback conveyance unit 20 includes a switchback conveyance path 21, a forward / reverse rotation roller 22, and a conveyance motor 23. The forward / reverse roller 22 is provided in the vicinity of the discharge port of the switchback transport path 21. The forward / reverse roller 22 has a drive roller and a driven roller, and the drive roller rotates clockwise (forward rotation: forward rotation: when the sheet Pi, the Z-folded sheet Pz, etc. are taken into the switchback conveyance path 21 and when the sheet is sent out. (See the arrow in the figure). When the sheet Pi is fed into the standby conveyance path, it is rotated (reversely rotated) counterclockwise.

  The transport motor 23 is attached to a predetermined position of the switchback transport unit 20, is connected to the forward / reverse roller 22, and rotates the forward / reverse roller 22 in a predetermined direction. In this example, the transport motor 23 rotates the take-in roller 11. By also using the transport motor 23, one motor installation number can be omitted.

  The branching unit 30 is provided between the switchback conveyance unit 20 and the standby position conveyance unit 40, and includes a conveyance path 31 for taking in the sheet P1, the Z-folded sheet Pz, and the like, and a conveyance path for standby for waiting the sheet Pi. And 32. For example, the branch part 30 includes a long and narrow triangular prism-shaped branch member 33. The conveyance path 31 and the conveyance path 32 are separated from each other by a triangular prism-shaped acute angle portion of the branch member 33.

  Of course, a solenoid element (not shown) may be attached to the branch member 33 to perform branch control of the sheet P1, the Z-folded sheet Pz, and the like. For example, when taking in the sheet P1, the Z-folded sheet Pz, and the like, the sheet P1, the Z-folded sheet Pz, and the like are guided to the forward / reverse roller 22 so as to descend the acute angle portion of the branch member 33. When waiting for the sheet Pi, the acute angle portion of the branch member 33 may be raised to guide the sheet Pi to the standby position conveying unit 40.

  The overlapping position of the sheet P1, the Z-folded sheet Pz, etc. may be anywhere as long as it is within the range from the triangular prism-shaped acute angle portion of the branch member 33 to the nip position of the forward / reverse roller 22 of the switchback transport unit 20. . At a position within this range, a sheet bundle in which one sheet that has not been folded or two or more sheets Pi that are superimposed and one Z-folded sheet Pz that has been Z-folded is superimposed is sent out. I can do it.

  In this example, a standby position transport unit 40 is provided on the right side of the branch unit 30. The standby position conveyance unit 40 detects the capture of the second and subsequent sheets Pi + 1 from which the leading edge detection sensor 12 detects the capture of the sheet Pi reversely conveyed to the standby position by the switchback conveyance unit 20 in the multiple sheet stacking mode. The first and subsequent sheets Pi are conveyed from the standby position toward the overlapping position.

  Here, the “multiple sheet stacking mode” refers to an operation in which a plurality of sheets Pi are stacked and sent out by a set number. In this multi-sheet stacking mode, the first sheet, the second sheet or more that have not been folded are taken into the standby position transport unit 40, and the first sheet, the second sheet or more Further, the nth sheet Pn is taken into the sheet Pi from the outside, and the respective leading ends are overlapped to discharge a total of a plurality of sheets of sheets Pi + Pn.

  In addition, the standby position conveyance unit 40 moves from the standby position toward the superposition position based on the conveyance start timing determined by the control unit 50 based on the trailing edge detection time of the Z-folded sheet Pz in the Z-folding mode. The sheet Pi is conveyed. Here, the Z-folding mode refers to an operation in which one or more sheets and finally a Z-folding sheet are stacked and sent. In the Z-folding mode, the first sheet, the second sheet or more, which has not been folded, is taken into the standby position transport unit 40, and the first sheet, the second sheet or more Further, a Z-folded sheet Pz is further taken into the sheet Pi from the outside, and the leading ends of the Z-folded sheets Pz are overlapped to discharge a total of a plurality of sheets of sheets Pi + Z folded sheets Pz.

  The standby position transport unit 40 includes a standby transport path 41, two forward / reverse rollers 42 and 43, and a transport motor 44. The forward / reverse roller 42 has a driving roller and a driven roller, and is disposed in the vicinity of the sheet entrance / exit of the standby conveyance path 41. The forward / reverse rotation roller 43 also has a driving roller and a driven roller, and is arranged at the end position of the standby conveyance path 41. Established.

  When the forward and reverse rollers 42 and 43 take in the sheet Pi from the switchback conveyance path 21 to the standby conveyance path 41, the drive rollers rotate counterclockwise (reverse rotation: see arrows in the figure). When the sheet Pi is sent from the standby conveyance path 41 to the switchback conveyance path 21, the drive rollers of the forward and reverse rotation rollers 42 and 43 are rotated clockwise (forward rotation).

  The transport motor 44 is attached to a predetermined position of the standby position transport unit 40, connected to the two forward / reverse rollers 42 and 43, and rotationally drives the forward / reverse rollers 42 and 43 in a predetermined direction. For example, a brushless motor (induction motor) is used as the above-described transport motors 23 and 44.

  The control unit 50 sequentially feeds one or more sheets Pi taken into the switchback conveying unit 20 via the take-in roller 11 at the overlapping position, and the leading end of each sheet Pi, Z-folded sheet Pz, etc. The switchback conveyance unit 20 and the standby position conveyance unit 40 are controlled so that the units overlap each other. For example, the control unit 50 operates based on a reference clock signal (hereinafter referred to as a CLK signal), an A / D conversion unit 51, a counter 52, a ROM (Read Only Memory) 53, a RAM (Random Access Memory) 54, a central calculation. An apparatus (Central Processing Unit: hereinafter referred to as CPU 55) and a motor control unit 56 are configured.

  An operation & display unit 48 is connected to the control unit 50. The control unit 50 reads out the system program Dp stored in the ROM 53 and various processing programs by the operation of the operation & display unit 48 and develops them in the RAM 54, and the operation of the sheet overlap feeding device according to the developed system program Dp. Centralized control. For example, the CPU 55 executes sheet overlap sending control in the switchback conveyance unit 20 and the standby position conveyance unit 40 according to the developed program.

  The operation & display unit 48 includes a touch panel and an LCD (Liquid Crystal Display). For example, the operation & display unit 48 is operated so as to select one of the two overlapping operation modes. In this example, with respect to the stacking operation mode, a multiple-sheet stacking mode and a Z folding mode can be selected.

  The operation & display unit 48 includes various operation buttons such as a numeric button and a start button, and outputs operation data D48 by the button operation to the control unit 50. The operation data D48 includes setting information when one of the two overlapping operation modes is selected. When the sheet overlap sending apparatus 100 is used in tandem with an image forming apparatus (not shown) on the upstream side, the operation data D48 may be supplied from the image forming apparatus, and therefore the operation & display unit 48 may be omitted.

  The input side of the A / D converter 51 is connected to the first leading edge detection sensor 12 and the second trailing edge detection sensor 13, and the respective output sides thereof are connected to the counter 52 and the system bus 57. The A / D converter 51 receives the tip detection signal S12 from the tip detection sensor 12, converts the tip detection signal S12 from analog to digital, and outputs the tip detection data D12 to the counter 52 and the CPU 55. The A / D converter 51 receives the rear end detection signal S13 from the rear end detection sensor 13, converts the rear end detection signal S13 from analog to digital, and outputs the rear end detection data D13 to the CPU 55.

  The counter 52 constitutes an example of a counting unit, and counts the number of sheets Pi waiting at the standby position. For example, the counter 52 counts the number of sheets P1, sheets P2, etc. based on the leading edge detection data D12 output from the A / D converter 51, and outputs the sheet number data D52. The sheet number data D52 is output from the counter 52 to the CPU 55. The CPU 55 can recognize the number of sheets Pi at the time of standby based on the sheet number data D52 output from the counter 52.

  The motor control unit 56 is connected to the transport motors 23 and 44. The motor control unit 56 controls the transport motors 23 and 44 based on the motor drive data D56. For example, the motor control unit 56 decodes the motor drive data D56 and generates motor control signals S23 and S44. The motor drive data D56 is data for superimposing the succeeding sheet Pi + 1, the Z-folded sheet Pz, etc. on the leading edge of the waiting sheet Pi with good reproducibility, and is output from the CPU 55 to the motor controller 56. The motor control signal S23 is output from the motor control unit 56 to the transport motor 23.

  The motor control signal S44 is a signal for superimposing the succeeding sheet Pi + 1, the Z-folded sheet Pz, etc. on the leading edge of the waiting sheet Pi with good reproducibility, and is output from the motor control unit 56 to the conveyance motor 44. . In this example, according to the setting of the overlapping operation mode, the motor control signal S44 (i) is output in the multiple stacking mode, and the motor control signal S44 (z) is output in the Z folding mode.

  The CPU 55 starts the conveyance start timing of the sheet Pi that is conveyed from the standby position toward the overlapping position based on the leading edge detection signal S12 of the sheet Pi + 1 that is output from the leading edge detection sensor 12 in the multi-sheet overlapping mode (see FIG. 7). Time t2) is set. In the Z-folding mode, the CPU 55 inputs a rear end detection signal S13 obtained by detecting the rear end of the Z-folded sheet Pz from the rear end detection sensor 13, and waits from the rear end detection signal S13 of the Z-folded sheet Pz. The conveyance start timing (time t4 in FIG. 7) of the position sheet Pi is set.

  At the same time, the CPU 55 calculates time information from the time when the trailing edge of the Z-folded sheet Pz is detected based on the trailing edge detection signal S13 of the Z-folded sheet Pz to the conveyance start timing of the sheet Pi at the standby position. Based on the time information calculated here and the length information of the Z-folded sheet Pz, the conveyance start timing of the sheet Pi at the standby position is determined. The standby position conveyance unit 40 is controlled based on the conveyance start timing of the sheet Pi determined here. In this example, the sheet Pi and the Z-folded sheet Pz are superposed with the conveyance speed of the sheet Pi being fixed based on the determined conveyance start timing (first embodiment).

<Operation example in multi-stack mode>
Next, with reference to FIGS. 2 to 4, an operation example (Nos. 1 to 3) in the multiple sheet stacking mode in the sheet stacking and sending apparatus 100 will be described. In this example, a case is described in which a plurality of sheets Pi are overlapped and sent out by setting a plurality of sheets overlapping mode.

  2A, in the multiple sheet stacking mode, for example, in the two sheet stacking mode, the take-in roller 11 and the forward / reverse rotation roller 22 are driven to switch back the first sheet P1. Part 20 is drawn. At this time, the leading edge detection sensor 12 detects the leading edge of the sheet P1. 2B, the first sheet P1 arrives at the switchback conveyance unit 20. At the time of arrival, the rear end portion of the sheet P1 is positioned downstream of the triangular prism-shaped acute angle portion of the branch member 33.

  3A, the forward / reverse rotation roller 22 and the forward / reverse rotation rollers 42 and 43 are driven, the first sheet P1 is reversely conveyed, and reaches the standby position conveyance unit 40. The sheet P1 that has reached the standby position conveyance unit 40 becomes a standby sheet. At the same time, the leading edge detection sensor 12 detects the second sheet P2.

  3B, the take-in roller 11 and the forward / reverse roller 22 are driven so that the second sheet P2 (subsequent sheet) is drawn into the switchback conveyance unit 20 and 2 After waiting time T1 from the time when the first sheet P2 is detected, the forward and reverse rollers 42 and 43 are driven to start conveying the first sheet P1 (standby sheet material) to the switchback conveying unit 20. Then, the leading ends of the first and second sheets P1 and P2 arrive at the switchback conveying unit 20, and the leading ends of the sheets P1 and P2 overlap each other.

  4, the forward / reverse rotation roller 22 and the forward / reverse rotation rollers 42 and 43 are driven in a state in which the leading ends of the sheets P1 and P2 are overlapped. The rear end portion of P2 is positioned downstream of the triangular prism-shaped acute angle portion of the branching member 33. As a result, two sheets of sheets P1 and P2 can be sent out in the two-sheet stacking mode.

<Operation example in Z folding mode>
Next, with reference to FIG. 5 and FIG. 6, an operation example (Nos. 1 and 2) in the Z-folding mode in the sheet overlap sending apparatus 100 will be described. In this example, the Z-folding mode is set, the Z-folded sheet Pz is taken into the single sheet P1 from the outside, the respective leading ends are overlapped, and a total of two bundle-like sheets P1 + Z-folded sheets Pz are obtained. List when sending.

  5A, the Z-folding mode is set, and when the sheet P1 in the standby position and the Z-folded sheet Pz captured from the outside are overlapped, the Z-folding is performed from the upstream side. The sheet Pz is conveyed. At this time, the leading edge detection sensor 12 detects the leading edge of the Z-folded sheet Pz, but it is indefinite. The trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz and generates a trailing edge detection signal S13.

  5B, the take-up roller 11 and the forward / reverse roller 22 are driven to draw the Z-folded sheet Pz (subsequent sheet) into the switchback conveying unit 20 and the Z-folded sheet. After a predetermined time has elapsed from the time when Pz is detected, the forward and reverse rollers 42 and 43 are driven, and the conveyance of the sheet P1 (standby sheet material) at the standby position to the switchback conveyance unit 20 is started. Then, the leading end portion of the sheet P1 and the leading end portion of the Z-folded sheet Pz arrive at the switchback conveyance unit 20, and the leading end portion of the sheet P1 and the leading end portion of the Z-folded sheet Pz overlap each other.

  6, the forward / reverse rotation roller 22 and the forward / reverse rotation rollers 42 and 43 are driven in a state where the leading ends of the sheet P1 and the Z-folded sheet Pz overlap each other. A bundle of sheets P1 + Z folded sheets Pz can be sent out (Z folding mode).

  Next, with reference to FIGS. 7A to 7C, an example of sheet detection in the multi-sheet stacking mode and the Z-folding mode in the sheet stacking apparatus 100 as the first embodiment will be described. The operation time charts shown in FIGS. 7A to 7C are a summary of the sheet detection timing in the multi-stack mode by the leading edge detection sensor 12 and the Z-fold sheet detection timing in the Z-folding mode by the trailing edge detection sensor 13. is there. The CLK signal shown in FIG. 7A is a reference signal for driving the control unit 50 shown in FIG. The tip detection signal S12 shown in FIG. 7B is output to the A / D converter 51 from the tip detection sensor 12 shown in FIG.

  The leading edge detection signal S12 falls from the high level to the low level to indicate the presence of a sheet (sheet arrival). The leading edge detection signal S12 rises from the low level to the high level to indicate no sheet (sheet not reached). In this example, in the multiple sheet stacking mode, the transport speed V of the sheet Pi transported from the standby position toward the stack position at time t2 after the standby time T1 has elapsed with reference to the CLK signal at time t1. Is set.

  The rear end detection signal S13 illustrated in FIG. 7C is output from the rear end detection sensor 13 illustrated in FIG. 1 to the A / D conversion unit 51 in the Z folding mode. The trailing edge detection signal S13 falls from the high level to the low level, and originally indicates that there is a sheet (sheet arrival). However, in the case of the Z-folded sheet Pz, the edge of the Z-fold head becomes unclear. ing. The jagged mark in the figure indicates a state in which the rising edge of the trailing edge detection signal S13 is not fixed because the Z-fold head of the Z-folded sheet Pz is detected. This state is hereinafter referred to as tip approximate detection.

  The trailing edge detection signal S13 rises from the low level to the high level to indicate no sheet (sheet not reached). In this example, in the Z-folding mode, the conveyance start timing of the sheet Pi conveyed from the standby position toward the overlapping position at time t4 after the standby time T2 has elapsed with reference to the CLK signal at time t3. Is set.

  Thus, the CPU 55 sequentially stacks a plurality of sheets Pi, Z-folded sheets Pz, and the like that are taken into the switchback conveyance unit 20 via the take-in roller 11 based on the front-end detection signal S12 obtained from the front-end detection sensor 12. At the alignment position, the switchback conveying unit 20 and the standby position conveying unit 40 can be controlled so that the leading ends of the sheets P1 and the Z-folded sheet Pz are overlapped.

  Here, an example of conveying the sheet Pi at the standby position as the first embodiment will be described with reference to FIG. The graph shown in FIG. 8 summarizes conveyance examples of the sheet Pi conveyed from the standby position toward the overlapping position in the multi-sheet overlapping mode and the Z-folding mode.

  In FIG. 8, the vertical axis represents the conveyance speed V of the sheet Pi (standby sheet), which is a speed depending on the forward / reverse rotation roller 42. The forward / reverse roller 42 depends on the rotational speed of the transport motor 44. The horizontal axis is the time t before and after the conveyance of the sheet Pi, and the time before and after the forward / reverse rotation roller 42 is turned on (activated).

  A broken line indicates a setting example of the conveyance speed of the sheet Pi (standby sheet) conveyed from the standby position to the overlapping position in the multiple sheet stacking mode. In this example, when the leading edge detection sensor 12 shown in FIG. 1 detects the leading edge of the sheet P2 (subsequent sheet) at time t1, the time after the CPU 55 shown in FIG. 1 passes the standby time T1 from the time t1. At t2, the forward / reverse rotation roller 42 is turned on (started up), the conveyance speed V is increased at a constant inclination θ1, and the sheet P1 is conveyed from the standby position toward the overlapping position. The acceleration in this case is dV / dt. In this example, the leading ends of the sheets P1 and P2 arrive at the switchback conveying unit 20, and at the time t5, the leading ends of the sheets P1 and P2 overlap (see FIG. 3B). The forward / reverse roller 43 is controlled in the same manner as the forward / reverse roller 42.

  A solid line indicates a setting example of the conveyance speed V of the sheet Pi (standby sheet) conveyed from the standby position in the Z-folding mode toward the overlapping position. In this example, when the trailing edge detection sensor 13 shown in FIG. 1 detects the trailing edge of the Z-folded sheet Pz (following sheet) at time t3, the CPU 55 shown in FIG. 1 elapses the waiting time T2 from the time t3. After that, at time t4, the forward / reverse roller 42 is turned on (started up), the conveyance speed V is increased at a constant inclination θ2 (θ2> θ1), and the sheet P1 is conveyed from the standby position toward the overlapping position, Then, the case where the conveyance speed V increasing with the inclination θ2 is changed to the conveyance speed V increasing with the inclination θ1 is shown. The forward / reverse roller 43 is controlled in the same manner as the forward / reverse roller 42.

  In this case, the leading ends of the sheet P1 and the Z-folded sheet Pz arrive at the switchback conveying unit 20, and for example, at the time t5, the leading ends of the sheet P1 and the Z-folded sheet Pz overlap (see FIG. 5B). ). Thus, the CPU 55 can execute the conveyance control of the sheet Pi conveyed from the standby position toward the overlapping position in the multiple sheet stacking mode and the Z folding mode.

  Next, with reference to FIG. 9, a control example of the sheet stacking apparatus 100 as the first embodiment will be described with respect to the first sheet processing method. In this embodiment, a superposition operation mode such as a multi-sheet superposition mode or a Z-fold superposition mode is prepared, the superposition operation mode setting and the set number of non-Z-fold sheets Pi are received, and the multi-sheet superposition mode is set. In this case, the set number of sheets Pi that have not been subjected to the Z-fold process are superimposed and sent out.

  When the Z-folding mode is set, an example in which the set number of sheets Pi that have not been subjected to Z-folding and the Z-folded Z-folded sheet Pz are overlapped at a predetermined overlapping position and sent out. To In this example, by using the through-pass function of the sheet stacking and feeding apparatus 100, the Z-folded sheet Pz is finally stacked on one or more sheets Pi at the standby position, and the downstream side is directly conveyed without being reversed and conveyed to the standby position. It is assumed that it will be sent to.

  Under these control conditions, in step ST1 shown in FIG. 9, the CPU 55 inputs the setting of the overlapping operation mode and the set number of sheets. At this time, the user selects a plurality of sheets overlapping mode or Z folding mode prepared in advance and sets the overlapping operation mode. For example, by operating the operation & display unit 48, the CPU 55 is instructed to the multi-sheet overlapping mode or the Z-folding mode, and the CPU 55 is instructed to set the number of sheets Pi to be superimposed. Thereafter, in step ST2, the CPU 55 branches the control in accordance with the setting of the overlapping operation mode. When the multiple sheet stacking mode is set, the process proceeds to step ST3.

  In step ST <b> 3, the CPU 55 executes processing for taking in the i-th non-Z-folded sheet Pi, waiting for a predetermined standby position after switching back the sheet Pi. At this time, the leading edge detection sensor 12 detects the leading edge portion of the sheet Pi taken into the switchback conveyance unit 20 and generates a leading edge detection signal S12. In the switchback conveyance unit 20, the conveyance motor 23 is driven to take in the first sheet P1 detected by the leading edge detection sensor 12 and convey it toward a predetermined overlapping position. The paper is reversed and conveyed to the standby position conveyance unit 40. As a result, the first sheet P1 waits at the standby position transport unit 40.

  Next, in step ST4, the CPU 55 controls the switchback conveyance unit 20 so as to take in the sheet Pi + 1 as the succeeding sheet, and inputs the leading edge detection signal S12 based on the leading edge detection of the sheet Pi + 1 (following sheet). The CPU 55 detects the falling time t1 of the tip detection signal S12 shown in FIG. 8B, starts a timer (not shown), and counts the waiting time T1 based on the turning on of the tip detection sensor 12. In the switchback conveyance unit 20, the conveyance motor 23 is driven to take in the sheet Pi + 1 detected by the leading edge detection sensor 12 and convey it toward a predetermined overlapping position.

  In step ST <b> 5, the CPU 55 activates the forward / reverse rotation roller 42 so as to start conveying the sheet Pi at the standby position to the switchback conveyance unit 20 at time t <b> 2 when the timer counts up and the standby time T <b> 1 has elapsed. At this time, a motor control signal S44 (i) is output from the motor control unit 56 to the conveyance motor 44 in order to start conveyance of the sheet Pi at time t2 when the standby time T1 shown in FIG. 8B has elapsed. In the standby position conveyance unit 40, the sheet Pi is conveyed from the standby position toward the overlapping position based on the rotation of the conveyance motor 44.

  After that, in step ST6, the CPU 55 controls the speed so that the rotation speeds of the transport motor 23 and the transport motor 44 coincide with each other, and the sheet Pi (standby sheet) and the next sheet Pi + 1 (following sheet) are overlapped. Overlapping. By this sheet superposition control, a total of (i + 1) sheets P1, P2,... Pi, Pi + 1 can be sent out. Thus, for example, when i = 1, the leading end of the sheet P1 and the leading end of the sheet P2 are overlapped at the overlapping position so that a sheet bundle in which a total of two sheets P1 and P2 are overlapped can be sent. (See FIG. 4).

  Thereafter, in step ST7, the CPU 55 determines whether or not the sheet Pi has reached the set number. In this case, the determination criterion is to detect the coincidence by comparing the previously set number of sheets with the count value of the counter. If the set number matches the count value of the counter, it is determined that the sheet Pi has reached the set number. If the set number is larger than the count value of the counter, it is determined that the sheet Pi has not reached the set number.

  When the number of sheets Pi reaches the set number, the sheet stacking control in the multiple stacking mode is terminated. If the number of sheets Pi has not reached the set number, the process returns to step ST3, and the CPU 55 continues the above-described sheet superposition control.

  When the Z-folding mode is set in the above-described step ST2, the CPU 55 executes a non-Z-fold sheet Pi stacking process in step ST8. The contents of this superposition process are the same as the contents of steps ST3 to ST6, so refer to it.

  In step ST9, the CPU 55 determines whether or not the sheet Pi at the standby position has reached the set number and branches the control. Refer to step ST7 for the criteria for determining the number of sheets Pi to be reached at that time. If the number of sheets Pi at the standby position has not reached the set number, the process returns to step ST8, and the CPU 55 continues the superimposing process of the non-Z-folded sheets Pi.

  When the number of sheets Pi at the standby position has reached the set number, the length of the Z-folded sheet Pz in the transport direction is determined in step ST10 in order to execute a process of superimposing the leading end of the sheet Pi and the leading end of the Z-folded sheet Pz. Enter the information. The length information may be measured in real time, but is stored in advance by the control unit 50. For example, when the Z direction is applied to the longitudinal direction of the A3 plate (horizontal) sheet, the length is half of the sheet length of the A3 plate and is equal to the width of the A4 (vertical) plate.

  In step ST11, the CPU 55 controls the switchback conveyance unit 20 to take in the Z-folded sheet Pz (following sheet), and inputs a rear end detection signal S13 based on the rear end detection of the Z-folded sheet Pz. At this time, the switchback conveyance unit 20 drives the conveyance motor 23 to take in the Z-folded sheet Pz detected by the trailing edge detection sensor 13 and convey it toward a predetermined overlapping position. Further, the rear end detection sensor 13 detects the rear end portion of the Z-folded sheet Pz taken into the switchback conveyance unit 20 and generates a rear end detection signal S13.

  The CPU 55 detects the rising time t3 of the rear end detection signal S13 shown in FIG. 7C, starts a timer (not shown), and counts the standby time T2 (time information) based on the ON of the rear end detection sensor 13. . The count-up value at this time is based on the length information of the Z-folded sheet Pz and the conveyance speed information of the Z-folded sheet Pz from the rear end detection signal S13 including the time t3 when the rear end of the Z-folded sheet Pz is detected. This is a value obtained by reversely calculating the time when the leading edge of the Z-folded sheet Pz is detected.

  Thereafter, in step ST12, the CPU 55 determines the conveyance start timing of the sheet Pi conveyed from the standby position toward the overlapping position based on the length information in the conveyance direction of the Z-folded sheet Pz and the standby time T2 (time information). To do. The conveyance start timing is determined based on the standby time T2 obtained by dividing the conveyance speed information of the Z-folded sheet Pz by the length information to obtain a standby time T2 (conveyance movement time). The standby position conveyance unit 40 is controlled based on the conveyance start timing of the sheet Pi determined here.

  In this example, after the counter counts up and the standby time T2 has elapsed, the forward / reverse rotation roller 42 is activated, and the conveyance of the sheet Pi from the standby position to the overlapping position is started at the conveyance start timing. Note that the conveyance start timing of the sheet Pi is time t4 after the standby time T2 obtained by the trailing edge detection of the Z-folded sheet Pz has elapsed (see FIG. 8).

  In step ST13, the CPU 55 performs speed control so that the rotation speeds of the conveyance motor 23 and the conveyance motor 44 are matched, and the sheet Pi (standby sheet) and the Z-fold sheet Pz (subsequent sheet) are overlapped at the overlapping position. Match. With this sheet superposition control, a sheet bundle in which a total of (i + 1) sheets P1, P2,... Thus, for example, when i = 1, the leading end portion of the sheet P1 and the leading end portion of the Z-folded sheet Pz are overlapped at the overlapping position, and a total of two sheets P1 and Z-folded sheet Pz are overlapped. The bundle can be sent out (see FIG. 6).

  As described above, according to the sheet overlap delivery device 100 according to the first embodiment, one sheet that has not been subjected to the Z-folding process, or a sheet Pi that has two or more overlapped sheets, and one sheet that has been subjected to the Z-folding process. When the Z-folded sheet Pz is overlapped and sent out at a predetermined overlapping position, the CPU 55 determines the sheet Pi that the standby position conveying unit 40 has reversed and conveyed to the standby position by the switchback conveying unit 20. Based on the conveyance speed V, the sheet is conveyed from the standby position toward the overlapping position (conveyance control of the sheet Pi at the standby position).

  With this conveyance control, regardless of the conveyance timing (conveying speed) at which the Z-folded sheet Pz is taken, the leading end portion of the sheet Pi conveyed from the standby position toward the overlapping position during the conveyance, and the sheet It is possible to superimpose the leading end portion of the Z-folded sheet Pz that is fetched last after Pi with good reproducibility (without inferiority).

  As a result, during post-processing operations such as binding processing, only the sheet Pi before superimposing the Z-folded sheet Pz is superposed on the sheet bundle obtained by superimposing the sheet Pi to be post-processed and the Z-folded sheet Pz. Thus, the standby position conveyance unit 40 can be made to wait.

  Therefore, when the next post-processing order arrives, a post-processing such as a rapid binding process is performed on the sheet bundle in which the sheets Pi and the Z-folded sheet Pz are overlapped by using the through-pass function of the sheet overlap sending apparatus 100. Since the sheet can be conveyed to the system, the productivity in the sheet overlap delivery apparatus 100 can be improved.

  For example, a post-processing operation is performed next in a post-processing operation in which a Z-folded sheet Pz obtained by Z-folding the A3 plate is superimposed on the end of a bundle of A4 sheets P1 and P2 to perform stapling processing, punching processing, and the like. The sheet material bundle in a state in which the A4 size sheets P1 and P2 are superposed can be made to wait in the standby position conveying unit 40.

  Next, with reference to FIGS. 10A to 10C, an example of sheet detection in the multiple sheet stacking mode and the Z folding mode in the sheet stacking apparatus 100 as the second embodiment will be described.

  In this embodiment, when the leading edge detection sensor 12 roughly detects the leading edge of the Z-folded sheet Pz, the CPU 55 starts the parting conveyance of the sheet Pi at the standby position from the standby position to the overlapping position at a predetermined conveyance speed. When the trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz after starting the conveyance, the conveyance speed of the sheet Pi is changed (adjusted).

  The operation time chart shown in FIGS. 10A to 10C is a summary of the sheet detection timing in the multiple stacking mode by the leading edge detection sensor 12 and the Z folding sheet detection timing in the Z folding mode by the trailing edge detection sensor 13. is there.

  The CLK signal shown in FIG. 10A is a reference signal for driving the control unit 50 shown in FIG. The tip detection signal S12 'illustrated in FIG. 10B is output to the A / D converter 51 from the tip detection sensor 12 illustrated in FIG. The tip detection signal S12 'output from the tip detection sensor 12 to the A / D conversion unit 51 has the same contents as those in the first embodiment, and a description thereof will be omitted.

  The rear end detection signal S13 shown in FIG. 10C rises from the low level to the high level when the rear end of the Z-folded sheet Pz is detected in the Z-folding mode. The rear end detection signal S13 is output to the A / D converter 51 from the rear end detection sensor 13 shown in FIG.

  In this example, when the leading end of the Z-folded sheet Pz is roughly detected, the sheet Pi at the standby position is started and conveyed after a predetermined time has elapsed, and sheet stacking control is executed. When the edge is detected, the conveyance speed of the sheet Pi toward the overlapping position is changed (adjusted). When the parting conveyance of the sheet Pi is started, the standby time T1 'substantially equal to the standby time T1 described in the first embodiment is set at the time t1' of the leading edge approximate detection.

  T <b> 2 ′ illustrated in FIG. 10C is a period during which the parting conveyance can be started. The parting conveyance start possible period T2 'is set continuously to the standby time T1' and continues until time t4 'when the trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz. In this example, the conveyance speed V of the sheet Pi conveyed from the standby position toward the overlapping position is set at time t3 ′ after the standby time T1 ′ has elapsed with reference to the CLK signal at time t1 ′. The part-off conveyance of the sheet Pi at the standby position is started. After the start of conveyance, the CPU 55 changes (adjusts) the conveyance speed of the sheet Pi at time t4 'when the trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz.

  Here, with reference to FIG. 11, an example of conveying the sheet Pi at the standby position as the second embodiment will be described. The graph shown in FIG. 11 summarizes conveyance examples of the sheet Pi conveyed from the standby position toward the overlapping position in the multiple sheet stacking mode and the Z folding mode.

  In FIG. 11, the vertical axis represents the conveyance speed V of the sheet Pi (standby sheet), which is a speed depending on the forward / reverse rotation roller 42. The forward / reverse roller 42 depends on the rotational speed of the transport motor 44. The horizontal axis is the time t before and after the conveyance of the sheet Pi, and the time before and after the forward / reverse rotation roller 42 is turned on (activated).

  A broken line indicates a setting example of the conveyance speed of the sheet Pi (standby sheet) conveyed from the standby position to the overlapping position in the multiple sheet stacking mode. In this example, when the leading edge detection sensor 12 shown in FIG. 1 detects the leading edge of the sheet P2 (subsequent sheet) at time t1 ′, the CPU 55 shown in FIG. 1 has passed the waiting time T1 ′ from the time t1 ′. The case where the forward / reverse rotation roller 42 is turned on (started) at a later time t2 ′, the conveyance speed V is increased at a constant inclination θ1 ′, and the sheet P1 is conveyed from the standby position toward the overlapping position is shown. .

  In this case, the leading ends of the sheets P1 and P2 arrive at the switchback conveyance unit 20, and, for example, at the time t5 ', the leading ends of the sheets P1 and P2 overlap (see FIG. 3B). The forward / reverse roller 43 is controlled in the same manner as the forward / reverse roller 42.

  A solid line indicates a setting example of the conveyance speed V of the sheet Pi (standby sheet) conveyed from the standby position in the Z-folding mode toward the overlapping position. In this example, the leading edge of the Z-folded sheet Pz (subsequent sheet) is roughly detected between time t1 'and time t2'. Further, within the period T2 ′ in which the parting conveyance can be started, in this example, at the time t3 ′ after the standby time T1 ′ has elapsed from the time t2 ′, the forward / reverse rotation roller 42 is turned on (started up), and the constant inclination θ2 ′ ( In this case, the conveyance speed V is increased when θ2 ′> θ1 ′), and the sheet P1 is parted and conveyed from the standby position toward the overlapping position.

  When the trailing edge detection sensor 13 shown in FIG. 1 detects the trailing edge of the Z-folded sheet Pz at time t4 ′, the CPU 55 shown in FIG. 1 increases the conveyance speed V that increases with the inclination θ2 ′ with the inclination θ1 ′. The case where it changes to the conveyance speed V which increases is shown. The above-described time t2 'indicates the start of the parting-off conveyance start possible period T2', and time t4 'indicates the end. The forward / reverse roller 43 is controlled in the same manner as the forward / reverse roller 42.

  In this case, the leading ends of the sheet P1 and the Z-folded sheet Pz arrive at the switchback conveying unit 20, and for example, at the time t5 ′, the leading ends of the sheet P1 and the Z-folded sheet Pz overlap (FIG. 5B). reference). Thus, the CPU 55 can execute the conveyance control of the sheet Pi conveyed from the standby position toward the overlapping position in the multiple sheet stacking mode and the Z folding mode.

  Next, with reference to FIG. 12, a control example of the sheet stacking apparatus 100 as the second embodiment will be described with respect to the first sheet processing method. In this embodiment as well, as in the first embodiment, a stacking operation mode such as a multi-sheet stacking mode or a Z-folding mode is prepared, and the setting of the stacking operation mode and the set number of non-Z-folded sheets Pi are performed. When the multiple sheet stacking mode is set, the set number of sheets Pi that have not been subjected to the Z folding process are overlapped and sent out.

  In this example, when the leading edge detection sensor 12 roughly detects the leading edge of the Z-folded sheet Pz, the CPU 55 starts the parting conveyance of the sheet Pi at the standby position from the standby position to the overlapping position at a predetermined conveyance speed, and starts conveyance. After that, when the trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz, the conveyance speed of the sheet Pi is changed (adjusted).

  Under these control conditions, in step ST21 shown in FIG. 12, the CPU 55 inputs the setting of the overlapping operation mode and the set number of sheets. Thereafter, in step ST22, the CPU 55 branches the control in accordance with the setting of the overlapping operation mode. When the multi-sheet superposition mode is set, the process proceeds to step ST23, but the control contents of steps ST21 to ST27 are the same as those of step ST1 to step ST7 of the first embodiment, and therefore the description thereof. Is omitted.

  In this example, if the Z-folding mode is set in step ST22, the CPU 55 executes a non-Z-fold sheet stacking process in step ST28. The contents of this superposition process are the same as the contents of steps ST3 to ST6, so refer to them.

  In step ST29, the CPU 55 determines whether or not the number of sheets Pi at the standby position has reached the set number. If the number of sheets Pi at the standby position has reached the set number, the leading edge of the sheet Pi and the leading edge of the Z-folded sheet Pz. In step ST30, length information in the transport direction of the Z-folded sheet Pz is input. The length information is as described in the first embodiment.

  In step ST31, the CPU 55 controls the switchback conveyance unit 20 to take in the Z-folded sheet Pz (following sheet), and inputs a leading edge detection signal S13 '(undefined) based on the leading edge rough detection of the Z-folded sheet Pz. At this time, the switchback conveyance unit 20 drives the conveyance motor 23 to convey the Z-folded sheet Pz taken from the outside toward a predetermined overlapping position. Further, the trailing edge detection sensor 13 roughly detects the leading edge of the Z-folded sheet Pz taken into the switchback conveyance unit 20 between the time t1 ′ and the time t2 ′ shown in FIG. 11, and detects the leading edge detection signal S13 ′. (Undefined) occurs.

  The CPU 55 activates a timer (not shown) at the start of the parting conveyance start possible period T2 'shown in FIG. 10C and counts the waiting time T1' (time information). The count-up value at this time is a time t3 'that determines the timing for starting the part-time conveyance of the sheet Pi at the standby position.

  Thereafter, in step ST32, the CPU 55 sets the conveyance speed V of the sheet Pi at the standby position after the standby time T1 ′ has elapsed within the period T2 ′ shown in FIG. The part-off conveyance of the sheet Pi is started. Whether or not the standby time T1 'has elapsed is determined by whether or not the counter has been counted up. In this example, at time t3 ′ when the counter is counted up, the forward / reverse rotation roller 42 is turned on (started up), and the conveyance speed V is increased with a constant inclination θ2 ′ (θ2 ′> θ1 ′). The parting conveyance of the sheet P1 is performed toward the overlapping position.

  Then, after the conveyance starts, in step ST33, the CPU 55 changes the conveyance speed V to the conveyance speed V based on the length information in the conveyance direction of the Z-folded sheet Pz after the parting conveyance start possible period T2 ′ has elapsed from the start of the partial conveyance (start). adjust. At this time, when the trailing edge detection sensor 13 shown in FIG. 1 detects the trailing edge of the Z-folded sheet Pz at the time t4 ′ shown in FIG. 11, the CPU 55 tilts based on the length information of the Z-folded sheet Pz. The conveyance speed V that increases with θ2 ′ is changed (adjusted) to the conveyance speed V that increases with inclination θ1 ′. The standby position transport unit 40 is controlled based on the transport speed V of the sheet Pi changed here.

  In step ST34, the CPU 55 performs speed control so that the rotation speeds of the conveyance motor 23 and the conveyance motor 44 coincide with each other, and the sheet Pi (standby sheet) and the Z-fold sheet Pz (subsequent sheet) are overlapped at the overlapping position. Match. With this sheet superposition control, a sheet bundle in which a total of (i + 1) sheets P1, P2,... Thus, for example, when i = 1, the leading end portion of the sheet P1 and the leading end portion of the Z-folded sheet Pz are overlapped at the overlapping position, and a total of two sheets P1 and Z-folded sheet Pz are overlapped. The bundle can be sent out (see FIG. 6).

  In this case, the leading ends of the sheet P1 and the Z-folded sheet Pz arrive at the switchback conveying unit 20, and for example, at the time t5 ′, the leading ends of the sheet P1 and the Z-folded sheet Pz overlap (FIG. 5B). reference). Thus, similarly to the first embodiment, the CPU 55 can execute the conveyance control of the sheet Pi conveyed from the standby position toward the overlapping position in the multiple sheet stacking mode and the Z folding mode. Become.

  As described above, according to the sheet overlap sending device 100 according to the second embodiment, when the leading edge detection sensor 12 roughly detects the leading edge of the Z folded sheet Pz in the Z folding mode, the CPU 55 detects the sheet Pi at the standby position. The part-off conveyance is started from the standby position to the overlapping position at a predetermined conveyance speed. After the conveyance starts, when the trailing edge detection sensor 13 detects the trailing edge of the Z-folded sheet Pz, the CPU 55 changes the conveyance speed of the sheet Pi. (Adjust).

  With this conveyance control, regardless of the conveyance timing (conveying speed) at which the Z-folded sheet Pz is taken, the leading end portion of the sheet Pi conveyed from the standby position toward the overlapping position during the conveyance, and the sheet It is possible to superimpose the leading end portion of the Z-folded sheet Pz that is fetched last after Pi with good reproducibility.

  In this example, the case where the sheet conveyance control is performed based on the leading edge detection sensor 12 and the trailing edge detection sensor 13 has been described, but the present invention is not limited to this. For example, only the trailing edge detection sensor 13 may be used, and sheet conveyance control may be performed using the leading edge outline detection and trailing edge detection functions. In this case, when the trailing edge detection sensor 13 roughly detects the leading edge of the Z-folded sheet Pz, the sheet Pi is started to be conveyed from the standby position to the overlapping position at a predetermined conveyance speed. When the sensor 13 detects the trailing edge of the Z-folded sheet Pz, the conveyance speed of the sheet Pi may be changed. Thereby, in addition to the effect of the first embodiment, the downstream end detection sensor 12 can be omitted.

  In the embodiment described above, in the Z-folding mode, a case has been described in which the sheet Pi at the standby position is started and conveyed after the standby time T1 ′ has elapsed since the leading edge detection of the Z-folded sheet Pz is performed. It is not limited to this. For example, the leading edge detection of the Z-folded sheet Pz may be performed, and at the same time, the sheet Pi at the standby position may be parted and conveyed. The control burden on the CPU 55 can be reduced.

  The present invention provides an image forming system constructed by combining a printer for color, black and white, a copying machine, a multi-function machine, a finisher, and the like, with a plurality of sheet leading ends after image formation and a predetermined shape. The present invention is extremely suitable when applied to a sheet stacking and sending device that superimposes and sends folded folded sheets.

11 Capture roller 12 Leading edge and trailing edge detection sensor (sheet detection means)
13 Rear end detection sensor (sheet detection means)
20 Switchback conveying section (first sheet conveying section)
21 Switchback transport path (first sheet transport section)
22 Forward / reverse roller (first sheet conveying unit)
23 Conveying motor (first sheet conveying unit)
30 branch path 31, 32 transport path 33 branch member 40 standby position transport section (second sheet transport section)
41 Standby transport path (second sheet transport section)
42, 43 Forward / reverse roller (second sheet conveying unit)
44 Conveying motor (second sheet conveying unit)
50 Control unit 51 A / D conversion unit 52 Counter (counting unit)
53 ROM (control unit)
54 RAM (control unit)
55 CPU (control unit)
56 Motor control unit (control unit)
57 System bus (control unit)
100 Sheet stacking device (sheet processing device)

Claims (6)

A sheet processing apparatus that superimposes one unfolded sheet material that has not been folded, or two or more sheets folded, and one folded sheet material that has been folded, at a predetermined overlapping position. There,
Sheet detecting means for detecting the incorporation of the non-folded sheet material and the folded sheet material;
First sheet conveyance detected by the sheet detecting means and taking in at least the non-folded sheet material and conveying it toward a predetermined overlapping position, and then reversely conveying from the overlapping position to a predetermined standby position. And
A second sheet conveying unit that conveys the non-folded sheet material reversely conveyed to the standby position by the first sheet conveying unit from the standby position toward the overlapping position;
The length information in the conveyance direction of the folded sheet material is input, and the conveyance start timing of the non-folded sheet material conveyed from the standby position toward the overlapping position is determined based on the length information of the folded sheet material And a control unit that sets the determined conveyance start timing of the non-folded sheet material in the second sheet conveyance unit. Sheet detection means for outputting sheet detection information to the control unit,
A first sheet detecting unit provided at a predetermined position of the first sheet conveying unit and detecting at least a front end of the non-folded sheet material;
And a second sheet detection unit that detects at least a rear end of the folded sheet material, and is disposed in a sheet conveyance path that is separated from the first sheet detection unit by a predetermined length. Item 2. The sheet processing apparatus according to Item 1. The controller is
The time when the trailing edge detection information obtained by the trailing edge detection of the folded sheet material is input from the second sheet detection unit and the trailing edge of the folded sheet material is detected based on the trailing edge detection information of the folded sheet material Calculating the time information from the time to the conveyance start timing of the non-folded sheet material, determining the conveyance start timing of the non-folded sheet material based on the time information and the length information of the folded sheet material,
3. The sheet processing according to claim 2, wherein the non-folded sheet material and the folded sheet material are overlapped while the conveyance speed of the non-folded sheet material is fixed based on the determined conveyance start timing. apparatus. The controller is
When performing sheet conveyance control based on the first and second sheet detection units,
When the first sheet detection unit roughly detects the front end of the folded sheet material, the non-folded sheet material is started to be conveyed from the standby position to the overlapping position at a predetermined conveyance speed,
After the start of conveyance, when the second sheet detection unit detects the rear end of the folded sheet material, the conveyance speed of the non-folded sheet material is changed,
When performing sheet conveyance control based on the second sheet detection unit,
When the second sheet detection unit roughly detects the front end of the folded sheet material, the non-folded sheet material is started to be conveyed from the standby position to the overlapping position at a predetermined conveyance speed,
3. The sheet processing apparatus according to claim 2, wherein the conveyance speed of the non-folded sheet material is changed when the second sheet detection unit detects the rear end of the folded sheet material after the conveyance starts. A sheet processing apparatus that superimposes and sends a non-folded sheet material that has not been folded and a folded sheet material that has been folded at a predetermined overlapping position,
A process of superposing one sheet of non-folded sheet material or two or more sheets and waiting at a predetermined standby position;
A process of conveying the non-folded sheet material from the standby position toward the overlapping position, taking in the folded sheet material, and superimposing a leading end portion of the non-folded sheet material and a leading end portion of the folded sheet material; When running
Detecting a rear end of the folded sheet material taken into the overlapping position at a predetermined position;
Input the trailing edge detection information obtained by the trailing edge detection of the folded sheet material, and input length information in the conveying direction of the folded sheet material,
Time information from the time when the trailing edge of the folded sheet material is detected based on the trailing edge detection information of the folded sheet material to the conveyance start timing of the non-folded sheet material is calculated, and the time information and the length of the folded sheet material are calculated. Determine the conveyance start timing of the non-folded sheet material based on the information,
A sheet processing method, wherein the non-folded sheet material and the folded sheet material are overlapped while the conveyance speed of the non-folded sheet material is fixed based on the determined conveyance start timing. A sheet processing apparatus that superimposes and sends a non-folded sheet material that has not been folded and a folded sheet material that has been folded at a predetermined overlapping position,
A process of superposing one sheet of non-folded sheet material or two or more sheets and waiting at a predetermined standby position;
A process of conveying the non-folded sheet material from the standby position toward the overlapping position, taking in the folded sheet material, and superimposing a leading end portion of the non-folded sheet material and a leading end portion of the folded sheet material; When running
When the leading end of the folded sheet material taken into the overlapping position is roughly detected, the non-folded sheet material starts to be conveyed from the standby position to the overlapping position at a predetermined conveying speed, and after the conveyance starts, the folding is started. A sheet processing method comprising: changing a conveyance speed of the non-folded sheet material when a rear end of the sheet material is detected.

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