JP2012012158A - Sheet folding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet folding device by which a sheet can be folded in an accurate position with a simplified folding mechanism in performing folding processing on the sheet with a folding roller pair.SOLUTION: A second transport path is arranged in a direction of intersecting with a first transport path for guiding the sheet from a carry-in part to a carry-out part. The folding roller pair performing folding processing on the sheet and a folding deflection means for inserting a fold of the sheet in a nip part are arranged at the intersection part. The folding deflection means includes a driven roller which comes into press contact with the roller peripheral surface of the folding roller pair, and a shift means for shifting the driven roller from a waiting position to an actuation position. By the operation of shifting the driven roller from the waiting position outside the path to the actuation position, a sheet front end is fed to the nip part from an upstream-side guide path formed in the second transport path. At this point, the shift velocity of the driven roller is made higher than the velocity of the sheet sent from the first transport path.

Description

  The present invention relates to a sheet folding apparatus that folds an image-formed sheet, and relates to an improvement of a sheet folding mechanism that can fold a sheet at a precise crease position with a simple structure.

  In general, this type of sheet folding apparatus is widely known as an apparatus for folding and finishing a sheet on which an image has been formed by an image forming apparatus such as a printing machine, a printer apparatus, or a copying machine at a predetermined folding position. For example, Japanese Patent Application Laid-Open No. 2003-228620 proposes an apparatus that folds an image-formed sheet connected to a paper discharge port of an image forming apparatus for filing and transports the sheet to a subsequent binding processing apparatus.

  Thus, the sheet folding apparatus that folds the sheet in half or one-third and carries it out is configured as a post-processing apparatus of the image forming apparatus, or is built in the image forming apparatus or the binding processing apparatus. It is configured as a unit. Various folding specifications are known for filing according to the purpose of use, such as 1/2 folding, 1 / 3Z folding, and 1/3 letter folding.

  In view of this, a folding apparatus that is connected to or built in an image forming apparatus, a binding apparatus (finisher apparatus, bookbinding apparatus), or the like includes a folding processing mechanism and a conveyance mechanism that feeds and sets sheets. For example, Patent Document 1 discloses a folding plate in which a pair of rollers for folding a sheet bundle is provided on a stacking guide for aligning sequentially fed sheets in a bundle shape, and the roller pair is disposed at a position facing the roller pair across a path. Discloses an apparatus for inserting a fold of a sheet bundle into a nip point of a roller pair.

  Similarly, in Patent Document 2 and Patent Document 3, a pair of rollers and a folding plate (folding blade) are arranged in the sheet feeding path, and the folding position of the sheet is inserted at the nip point of the roller pair with the folding plate. An apparatus for folding is disclosed.

  Further, on the upstream side and the downstream side of the folding roll, the conveying means for feeding out the leading end and the trailing end of the sheet is constituted by a leading end stopper and a belt in Patent Document 2 and a roller in Patent Document 3, respectively. .

  After the sheet fed to the folding position is temporarily stopped, the sheet speed inserted by the folding blade, the sheet speed folded by the pair of folding rolls, the sheet speed fed out by the upstream conveying means, and the downstream conveying means Control is performed so that the sheet speed to be fed coincides with each other.

  As described above, in the folding mechanism that inserts the fold position of the sheet between the roll nips with the folding plate, the sheet speed inserted by the folding blade, the sheet speed folded by the pair of folding rolls, the sheet speed fed out by the upstream conveying means, There is a known problem that the crease position may be out of order if the sheet speeds fed by the downstream conveying means do not exactly match, and the respective timing control becomes complicated.

  Therefore, Patent Document 4 discloses a timing at which a fold line is formed by disposing a driven roller movably between a retracted position and a pressure contact position between the folding rolls that are in pressure contact with each other and located on the downstream side in the sheet transfer direction. Has proposed a folding mechanism for moving the driven roller from the retracted position to the press-contact position.

  According to this mechanism, the speed inserted by the driven roller, the speed of the folding roller, and the sheet speed fed out by the upstream conveying means are the same (since they are composed of the same roller), and there is no need to adjust the respective speeds.

  Also, for example, Patent Documents 5 and 6 disclose that the blade moving speed is set faster than the peripheral speed of the folding roller when the sheet bundle is inserted between the pair of press-fold folding rollers with a folding blade and folded. Yes.

  Patent Documents 7 and 8 disclose a configuration in which a deflecting unit acts in a state where both ends of a sheet are nipped between a conveying roller pair and a folding roller pair.

Japanese Patent Laying-Open No. 2008-247531 (FIG. 1) JP 2007-320665 A Japanese Patent Laying-Open No. 2008-007297 (FIG. 6) JP 2005008337 A JP 2001-002317 A JP 2008-184324 A JP 2006-290618 A JP 2007-015785 A

  As described above, there is already known a folding processing apparatus in which a folding position is inserted into a pair of rollers in which sheets fed from a carry-in entrance are pressed against each other by a folding blade. It is also known that when the crease position is misaligned, the finishing quality is greatly affected. Therefore, this type of sheet folding apparatus is devised so that the sheet is reliably conveyed by a conveyance mechanism that conveys the sheet and is not misaligned.

  Such misalignment of the folding position of the sheet is caused by a misalignment caused by conveyance unevenness of the conveyance mechanism of the leading end portion of the sheet positioned upstream of the fold and the conveyance mechanism of the trailing end portion of the sheet positioned downstream of the fold. The positional deviation caused by the conveyance speed unevenness of both the conveyance mechanisms and the folding roll and the positional deviation generated when the sheet is inserted into the nip portion of the folding roll are factors.

  In view of this, the present inventor has a conveying means (feeding conveying means) for feeding out the sheet downstream (rear end portion) of the sheet, and the upstream side (leading end portion) of the sheet is driven by the folding roller peripheral surface at a predetermined timing. As a result, it has been found that there is no possibility that a plurality of transport mechanisms interfere with each other to cause uneven transport speed.

  For example, a conveying unit that feeds the trailing end of the sheet is provided on the upstream side of the pair of folding rollers, and no special conveying unit is provided on the leading end of the sheet. Then, the driven roller waiting outside the path moves so as to come into contact with the circumferential surface of the roller positioned on the downstream side of the pair of folding rollers.

  As a result, the folding mechanism can be configured simply, and at the same time, the above-described shift factor of the folding position can be reduced.

  However, when the deflecting member having the driven roller is moved from the standby position to the operating position, the sheet may be wrinkled or distorted at the folding position and the crease may be skewed.

  Therefore, when the inventor guides the sheet to the nip position of the pair of folding rollers, the sheet leading end is carried into a guide path curved by the downstream conveying roller, and the sheet leading end is placed on one peripheral surface of the pair of folding rollers. The mechanism of extending the driven roller to the folding position by a driven roller that is in contact with and driven to the folding position, and the idea that the speed at which the driven roller is moved from the standby position outside the path to the operating position is faster than the sheet conveying speed.

  As a result, the leading edge of the sheet is not restrained by a conveyance roller or the like, and can be folded at an accurate position without being unnecessarily sagging due to the conveyance load of the curved guide path.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet folding apparatus that can fold a sheet with a pair of folding rollers so that the folding mechanism can be folded at a simple and accurate position.

  In order to achieve the above object, the present invention provides a pair of folding rollers for arranging a second conveyance path in a direction intersecting with the first conveyance path for guiding the sheet from the carry-in section to the carry-out section, and folding the sheet at the intersection. The folding means for inserting the sheet fold is disposed in the nip portion.

  The folding deflection means is composed of a driven roller that is in pressure contact with the peripheral surface of the pair of folding rollers, and a shift means that moves the folding roller from the standby position to the operating position. The driven roller is moved from the standby position outside the path to the operating position. In this way, the leading edge of the sheet is fed out from the upstream guide path formed in the second conveyance path to the nip portion. At this time, the moving speed of the driven roller is higher than the sheet speed sent from the first transport path.

  A first conveyance path (32) for folding the sheet from the carry-in unit (30) and carrying it out to the carry-out unit (31), and guiding the sheet from the carry-in unit to the carry-out unit without folding the sheet; The second conveyance path (33) disposed in the direction intersecting the first conveyance path and folding the sheet, and the folding roller pair (41b, 49, 50) disposed in the second conveyance path and folding the sheet. And folding deflecting means (53, 54) for inserting the fold position of the sheet into the nip portion of the folding roller pair.

  The second conveyance path includes an upstream guide path (first switchback path 34 described later) that branches from the intersection (K) with the first conveyance path and guides the sheet leading end, and downstream from the intersection. And a downstream guide path (second switchback path 35 to be described later) for guiding the sheet, and the folding roller pair is disposed at the intersection of the first conveyance path and the second conveyance path.

  The folding deflection means includes a driven roller that is in pressure contact with the circumferential surface of the pair of folding rollers located on the downstream side in the traveling direction of the sheet moving along the first conveying path, and a standby position in which the driven roller is retracted from the nip portion of the pair of folding rollers. And a shift means for moving the position between the operation position for guiding the sheet to the nip portion, and the shift means determines the speed at which the driven roller is moved from the standby position to the operation position in the first conveyance path. Set to be faster than the moving sheet speed.

  A sheet feeding / conveying means for feeding out the sheet toward the intersection is arranged on the first conveying path, and the upstream guide path of the first conveying path is configured by a curved path that applies a conveying load to the sheet.

  Then, the sheet front end is carried into the upstream guide path by the sheet feeding / conveying means, and the sheet front end is carried out from the upstream guide path by a driven roller that is driven in pressure contact with the circumferential surface of the pair of folding rollers.

  In this case, the sheet feeding / conveying means is constituted by a pair of rollers in pressure contact with each other, and the sheet pressing force of the sheet feeding / conveying means is set larger than the sheet pressing force between the driven roller and the circumferential surface of the folding roller.

  According to the present invention, a second conveying path having a pair of folding rollers is arranged in a direction intersecting with the first conveying path, and the folding deflecting means for inserting the sheet fold into the roller nip portion is pressed against the peripheral surface of the folding roller pair. And a shift means for moving the driven roller. The moving speed of the driven roller is made higher than the sheet speed sent from the first conveying path, and the leading end of the sheet is moved from the upstream guide path of the second conveying path to the roller nip. Since it is extended to the part, the following effects are produced.

  In a path configuration in which the second conveyance path is arranged in a direction intersecting with the first conveyance path and the folding roller pair is arranged at the intersection, the sheet leading end is disposed on the upstream side guide path of the second conveyance path from the first conveyance path. A plurality of conveying mechanisms act on the sheet guided to the nip portion because the sheet is fed and fed to the nip portion by a driven roller that moves the leading end portion of the sheet from the outside of the path to an operation position that presses the peripheral surface of the pair of folding rollers. Since the driven roller operates at a position close to the nip portion, the folding position of the sheet fed to the nip portion is less likely to shift.

  At the same time, by setting the moving speed of the driven roller higher than the sheet speed sent from the first conveying path, the sheet is bent when the sheet conveyed by the driven roller is guided to the nip portion of the pair of folding rollers. There is nothing to do.

  Then, the contact point where the conveyed sheet and the driven roller first contact each other is not displaced, and the driven roller is brought into contact with the contact point contacting the peripheral surface of the folding roller, so that the sheet is not wrinkled accurately. The folding position can be positioned at the roller nip portion.

  Further, by configuring the upstream guide path for guiding the sheet leading end portion in a curved shape, fluctuations in the sheet leading end portion can be reduced, and the sheet is not wrinkled or damaged at the fold position.

1 is an explanatory diagram of an overall configuration of an image forming system including a sheet folding apparatus according to the present invention. FIG. 2 is an explanatory diagram of an overall configuration of a sheet folding device in the system of FIG. 1. The principal part expansion explanatory drawing in the sheet folding apparatus of FIG. Explanatory drawing of the drive mechanism of the primary folding deflection | deviation means and secondary folding deflection | deviation means in the apparatus of FIG. The conceptual diagram showing the relationship between the moving speed of a deflection | deviation member, and a sheet conveyance speed. FIGS. 3A and 3B are explanatory views of a drive mechanism of a path switching unit in the apparatus of FIG. 2, in which FIG. 2A shows a state in which a sheet is conveyed to a first switchback path, and FIG. FIG. 3 is an explanatory diagram of an operation state of the apparatus of FIG. 2, (a) shows a registration state of the sheet, and (b) shows a state of transferring the sheet from the first path to the second path. FIGS. 3A and 3B are explanatory diagrams of an operation state of the apparatus of FIG. 2, in which FIG. 2A shows a state in which the deflecting member is in contact with the sheet, and FIG. 2B shows a state in which the sheet folding position is inserted into the first nip portion. FIGS. 3A and 3B are explanatory diagrams of an operation state of the apparatus of FIG. 2, in which FIG. 2A illustrates a state in which a primarily folded sheet is conveyed to a second switchback path, and FIG. Indicates. FIGS. 3A and 3B are explanatory diagrams of an operation state of the apparatus of FIG. 2, in which FIG. 2A shows a state where a sheet folding position is inserted into a second nip portion, and FIG. 2B shows a state where a folded sheet is carried out in a paper discharge direction. . It is a graph which shows the speed relationship of a deflecting member, (a) shows the speed of a deflecting member motor, (b) shows the speed of a deflecting member. It is explanatory drawing of the sheet folding specification in the sheet folding apparatus of this invention, (a) is a mode which folds a sheet | seat inside three at 1/3 position, (b) is a mode which Z-folds a sheet | seat at 1/3 position. (C) shows a mode in which the sheet is Z-folded at a 1/4 position. Explanatory drawing of the control structure in the system of FIG. 14 is a flowchart showing processing operations in the control configuration of FIG. 13.

  Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 shows an image forming system provided with a sheet folding apparatus according to the present invention. This system includes an image forming apparatus A and a post-processing apparatus C, and a sheet folding apparatus B is attached to the post-processing apparatus C as a unit.

  The image forming apparatus A is configured as a printer, a copier, a printer, or the like that sequentially forms images on sheets. The illustrated one is an image forming unit 7, a document reading unit 20, and a feeder unit (document feeding device) 25 as a composite copying machine having a copying machine function and a printer function. Further, the post-processing apparatus C is connected to the main body discharge port 18 of the image forming apparatus A, and is configured to perform post-processing such as folding, punching, stamping, and binding on the image-formed sheet. Has been. A sheet folding device B for folding the image-formed sheet is integrally provided in the post-processing device C. Hereinafter, the sheet folding apparatus B, the image forming apparatus A, and the post-processing apparatus C will be described in this order.

[Sheet folding device]
The sheet folding apparatus B according to the present invention is built in the image forming apparatus A or the post-processing apparatus C, or is configured as an independent apparatus (stand-alone configuration). The illustrated one is arranged as an optional unit between the image forming apparatus A and the post-processing apparatus C.

  The entire structure of the sheet folding device B is shown in FIG. 2, but a carry-in port 30 and a carry-out port 31 are provided in the device housing 29, and the carry-in port 30 is located at a position continuous with the main body discharge port 18 of the image forming apparatus A on the upstream side. The carry-out port 31 is arranged at a position continuous with the sheet receiving port 69 of the downstream post-processing apparatus C.

  In the present invention, the sheet folding apparatus B is not provided with an independent apparatus housing 29, but may be built in, for example, the casing of the post-processing apparatus C. In this case, the carry-in port 30 and the carry-out port 31 are required. do not do.

  Therefore, hereinafter, the carry-in port 30 is synonymous with the carry-in unit, and the carry-out port 31 is synonymous with the carry-out unit. For convenience of explanation, the carry-in unit will be described as the carry-in port 30 and the carry-out unit will be explained as the carry-out port 31.

  As shown in FIG. 2, the carry-in port 30 and the carry-out port 31 are disposed so as to cross the apparatus housing 29, and the illustrated carry-in port 30 and the carry-out port 31 are disposed at positions that are substantially opposed in the horizontal direction. Between the carry-in port 30 and the carry-out port 31, the sheet from the carry-in port 30 is folded without being folded, and the sheet from the carry-in port 30 is folded. The 2nd conveyance path | route 33 carried out to the carry-out exit 31 is arrange | positioned. A “sheet conveying mechanism” that conveys the sheet in a predetermined direction (horizontal direction) is arranged in the first conveying path 32, and a “folding mechanism” that folds the sheet is arranged in the second conveying path 33. .

Route configuration
As shown in FIG. 2, a first transport path (hereinafter referred to as “first path”) 32 is disposed in the apparatus housing 29 between the carry-in port 30 and the carry-out port 31. As shown in the figure, this path may be arranged in a horizontal direction as a straight path, or may be arranged in a vertical direction even if it is constituted by a curved path. As described above, the first path 32 guides the sheet from the carry-in entrance 30 to the carry-out exit 31 without folding the sheet.

  The second transport path (hereinafter referred to as “second path”) 33 is configured as a path for folding the sheet from the carry-in entrance 30. For this reason, the sheet is branched from the first path 32 to guide the sheet from the carry-in entrance 30 to the folding positions Np1 and Np2. At the same time, the second path 33 is arranged in a direction crossing the first path 32 as shown in FIG. 2, and the first folding position Np1 and the second folding position Np2 are set in this path.

  The second path 33 includes a first switchback path 34 that guides the leading edge of the sheet for primary folding to the first folding position Np1, and a folded sheet leading edge for secondary folding of the folded sheet at the second folding position. It comprises a second switchback path (downstream guide path: the same applies hereinafter) 35 for guiding to Np2.

  In this way, the second path 33 is arranged in a direction intersecting the first path 32, and the first switchback path 34 in the upper area of the first path 32 and the sheet from the intersection K in the lower area downstream (second folding). A second switchback path 35 that moves in the direction of the position Np2 is disposed oppositely.

  The first switchback path 34 and the second switchback path 35 are each configured by a curved path, and are formed in a substantially S-shaped curve as shown in FIG. In the second path 33, folding processing means (folding roller mechanism) 48, which will be described later, is disposed at the first folding position Np1 and the second folding position Np2, and the folded sheet from the second folding position Np2 is directed toward the carry-out port 31. A third transport path (hereinafter referred to as “third path”) 36 is continuously provided.

  The first path 32 and the second path 33 are arranged so as to cross each other, but the first switchback path 34 that guides the sheet to the first folding position Np1 is folded below the first path 32. A second switchback path 35 that guides the sheet to the downstream side may be disposed above the first path 32.

  2, the first path 32 is disposed in the horizontal direction. However, when the path 32 is disposed in the apparatus housing 29 in the vertical direction, the first switchback path 34 and the second switchback path 35 are arranged in the first direction. It is also possible to arrange it opposite to the left and right areas of the path 32.

  Further, in the form shown in FIG. 2, the second switchback path 35 is configured to reverse the sheet feeding direction in order to guide the folded sheet to the second folding position Np2 in order to perform the secondary folding of the sheet. However, when the sheet is not folded second, a straight path can be used.

  A third path 36 that guides the folded sheet to the carry-out port 31 is connected to the second path 33. The illustrated third path 36 is provided between the second folding position Np <b> 2 where the sheet is secondarily folded and the carry-out port 31. The third path 36 is provided with a paper discharge path 37 for guiding the folded sheet from the paper discharge outlet 51 different from the carry-out port 31 to the storage stacker 65.

  The first switchback path 34 configured as described above is configured by a path curved in an arc shape having a curvature R1 as shown in FIG. 2, and the second switchback path 35 is configured in an arc shape having a curvature R2. It consists of a curved path. Further, the paper discharge path 37 connected to the third path 36 is also configured as a circularly curved path having a curvature R3.

  Then, the path length (L1) of the first switchback path 34 for guiding the sheet from the first path 32 to the first folding position (first nip portion) Np1, and the first folded sheet at the second folding position. (Second nip portion) The path length (L2) of the second switchback path 35 for guiding to Np2 is configured such that path length L1> path length L2.

  Further, the path length L3 of the sheet discharge path 37 for guiding the folded sheet from the second folding position Np2 to the storage stacker 65 is configured to satisfy L3 <L2 <L1. This is because when the first folding position (first nip portion) Np1 is arranged in the vicinity of the first path 32, each path length becomes L3 <L2 <L1, resulting in a compact path configuration.

  As described above, the first switchback path 34 having the longest path length is disposed above the first path 32 and the second switchback path 35 having the short path length is disposed below. Similarly, the sheet is discharged below the first path 32. A path 37 is disposed, and a storage stacker 65 is disposed below the path 37.

  Accordingly, the first switchback path 34 having a long path length is disposed in the upper area of the first path 32, and the second switchback path 35 and the paper discharge path 37 having a short path length are disposed in the lower area so as to face the first switchback path 34. Further, a storage stacker 65 is disposed below the second switchback path 35 and the paper discharge path 37. With such a layout configuration, the inner space of the device housing 29 is concentrated.

"Route switching means"
A route switching means 63 is disposed at the intersection K between the first route 32 and the second route 33 described above. The path switching means 63 will be described with reference to FIG. 3. The sheet fed from the first path 32 is guided to the first switchback path 34 by a guide member pivotally supported by the support shaft 62x of the carry-out roller 62a (same as the first switchback path 34). (The solid line in the figure), or guide to the carry-out port 31 (broken line in the figure) or switch the path.

  A sheet guide 61 is provided at an intersection K between the first path 32 and the second path 33. The sheet guide 61 is disposed between the first roller (feeding and conveying roller pair) 41 b and the unloading roller pair 62 in the first path 32, and the sheet fed from the first path 32 is passed to the first switchback path 34. The shaft is supported so as to be swingable between a guiding posture (solid line in the figure) and a posture guiding the carry-out port 31 (broken line in the figure).

  The path switching means 63 and the sheet guide 61 described above are connected so as to be interlocked with each other. The interlocking mechanism is shown in FIGS. 6 (a) and 6 (b). As shown in the figure, a first link lever 60a is pivotally supported on a support shaft 62x of the path switching means 63, and the link lever and the path switching means 63 are integrally coupled.

  An electromagnetic solenoid 60L is connected to the tip of the first link lever 60a, and a return spring 60s is stretched over the path switching means 63 in the direction of guiding the sheet to the second path 33 side.

  On the other hand, the second link lever 60c is pivotally supported by the seat shaft 61x on the support shaft 61x, and the second link lever 60c and the seat guide 61 are coupled to rotate integrally. The first link lever 60a and the second link lever 60c are connected by an intermediate lever 60b.

  Accordingly, when the electromagnetic solenoid 60L is in the ON state, as shown in FIG. 6A, the first link lever 60a rotates by a predetermined angle around the support shaft 62x, and the path switching means 63 is moved to the first posture (the seat is moved to the second path 33). (Position to guide to). Further, in this state, the second link lever 60c rotates by a predetermined angle around the support shaft 61x, and positions the sheet guide 61 in the first guide posture (posture for guiding the sheet to the second path 33).

  When the electromagnetic solenoid 60L is turned OFF, as shown in FIG. 6B, the first link lever 60a is rotated counterclockwise around the support shaft 62x by the action of the return spring 60s, and the path switching means 63 is moved to the second posture. Position (position to guide the sheet to the carry-out port 31). At the same time, the second link lever 60c rotates counterclockwise about the support shaft 61x to change the sheet guide 61 to the second guide posture (the posture for guiding the sheet to the carry-out port 31).

"Folding roller configuration"
As shown in FIGS. 2 and 3, the second path 33 is provided with a folding roller mechanism including a pair of folding rollers. The first roller 41b, the second roller 49, and the third roller 50 are disposed at the intersection K of the first path 32 and the second path 33 so as to be in pressure contact with each other (see FIG. 3).

  A first nip portion (first folding position) Np1 for primary folding of the sheet is formed at the pressure contact between the first roller 41b and the second roller 49, and the sheet is applied to the pressure contact between the second roller 49 and the third roller 50. A second nip portion (second folding position) Np2 for secondary folding is formed.

  The diameters of the first, second and third rollers are the same outer diameter in the illustrated apparatus. This may be set to an appropriate size, for example, to maximize the second roller diameter.

  Further, as shown in FIG. 3, the first roller 41 b is disposed at a position where a part of the outer periphery faces the first path 32, and a pinch roller (floating roller) 41 a is pressed against the peripheral surface of the roller. The first roller 41b and the pinch roller 41a which are in pressure contact with each other constitute a sheet feeding / conveying means (hereinafter referred to as a “sheet feeding / conveying roller pair 41”) of the first path 32, whereby the sheet from the carry-in entrance 30 is moved downstream. Be transported.

[Configuration of folding deflection means]
As described above, the folding roller constituted by the three rollers (41b, 49, 50) has the primary folding deflection means 53 at the first nip portion Np1 and the secondary folding deflection means 54 at the second nip portion Np2. Is arranged (see FIG. 3).

  The illustrated apparatus has a function of “inserting the sheet folding position into the roller nip portion” and a function of “feeding the sheet front end portion into the nip portion” for the primary folding deflection means 53 and the secondary folding deflection means 54.

  For this reason, the primary and secondary folding deflecting means 53 and 54 are provided with driven rollers 53a and 54a, and are configured to move from the retracted position outside the path to the operating position in pressure contact with the circumferential surface of the folding roller. The movement of the driven roller from the standby position to the operating position acts to retract the sheet end portion into the roller nip portion.

"Configuration of primary folding deflection means"
The configuration of the primary folding deflection means 53 is shown in FIG. The primary folding deflection means 53 includes a driven roller 53a, a curved guide 53b, and an elevating member 53c. As shown in the figure, the driven roller 53a is rotatably supported by the elevating member 53c, and the curved guide 53b is integrally attached.

  The driven roller 53a is located at a position in contact with the circumferential surface of the second roller 49 located on the downstream side in the sheet moving direction of the first path 32, and the curved guide 53b is located along the circumferential surface of the first roller 41b located on the upstream side. Is arranged.

  The elevating member 53c is supported by a guide rail (not shown) provided on the apparatus frame and can reciprocate with a predetermined stroke. The elevating member 53c is provided with a cam groove 53d, and an operating lever 85a pivotally supported by a support shaft 85x on the apparatus frame is engaged with the cam groove 53d.

  The operating lever 85a is connected to the support shaft 85x via a spring clutch (torque limiter) 85d. A pulley 85b is provided on the support shaft 85x, and the rotation of the shift motor MS is transmitted to the pulley 85b by a transmission belt 85c.

  Therefore, if the shift motor MS is rotated in the forward direction (clockwise in FIG. 4), the operating lever 85a moves from the solid line state to the broken line state. Then, after the driven roller 53a comes into contact with the peripheral surface of the second roller 49, it is idled by the spring clutch 85d.

  When the shift motor MS is rotated in the opposite direction, the operating lever 85a rises from the broken line state to the solid line state, and after the elevating member 53c hits the stopper 53e, the spring clutch 85d is idled and locked at that position.

  A limit sensor Ls is disposed at this position, and the rotation of the shift motor MS is stopped by a state signal when the elevating member 53c is moved to a predetermined stopper position.

  On the other hand, the secondary folding deflecting means 54 is also supported so that the elevating member 54c moves up and down with a predetermined stroke on the apparatus frame in the same manner as the primary folding deflecting means 53, and a follower roller 54a and a curved guide 54b are provided. ing.

  The elevating member 53c is provided with a rack 54r and meshes with the pinion 54p. A shift motor MS is connected to the pinion 54p via a spring clutch 86a. The spring clutch 86a is set to transmit the rotation of the shift motor MS within a predetermined torque and to idle at a predetermined torque or more.

"Deviation means drive mechanism"
Next, the drive mechanism of the primary folding deflection means 53 and the secondary folding deflection means 54 will be described. As shown in FIG. 4, the primary folding deflector 53 is supported by a follower roller 53a and a curved guide 53b that move up and down at a predetermined stroke. The lifting member 53c is provided with an operating lever 85a that can swing around a support shaft 85x. That is, the elevating member 53c supported by the apparatus frame by a guide rail (not shown) so as to be movable up and down is provided with a cam groove 53d, and the cam groove 53d is disposed so that the tip of the operating lever 85a engages. .

  The operating lever 85a is connected to the support shaft 85x via a spring clutch 85d. At the same time, a pulley 85b is provided on the support shaft 85x, and the rotation of the shift motor MS is transmitted to the pulley 85b by a transmission belt 85c. Therefore, the spring clutch 85d is set to transmit the rotation of the shift motor MS from the support shaft 85x to the operating lever 85a. At the same time, the spring clutch 85d is idled between the support shaft 85x and a rotation of the shift motor MS is not transmitted to the operating lever 85a when a load exceeding a predetermined torque is applied.

  The primary folding deflection means 53 and the secondary folding deflection means 54 move the elevating member 53c from the retracted position to the operating position by the forward rotation of the shift motor MS, and the secondary folding deflection means by the rotation in this direction. The elevating member 54c is moved from the operating position to the retracted position.

  On the other hand, in the reverse rotation of the shift motor MS, the elevating member 54c of the secondary folding deflector 54 is moved from the retracted position to the operating position, and in this rotational direction, the elevating member 53c of the primary folding deflector 53 is moved from the operating position to the retracted position. Move position.

  In this way, the primary folding deflecting means 53 and the secondary folding deflecting means 54 are configured to reciprocally move between the operating position and the retracted position by forward and reverse rotation of the shift motor MS.

[Sheet transport mechanism]
The sheet conveyance mechanism of the first path 32 and the second path 33 will be described with reference to FIGS. In the first path 32, a pair of carry-in rollers 40 is arranged at a carry-in entrance (carry-in section) 30 and carries a sheet sent from the outside of the apparatus. A pair of paper feeding and conveying rollers 41 is disposed between the intersection K of the first path 32 and the second path 33 and the carry-in roller pair 40. The illustrated pair of paper feed / conveying rollers 41 includes a first roller 41b and a pinch roller 41a pressed against the first roller 41b.

  In the first path 32, a resist area Ar is provided on the downstream side of the carry-in roller pair 40, and a gate stopper 43 is disposed in the resist area Ar. The gate stopper 43 is configured to be swingable about the support shaft 43x, and temporarily corrects the leading edge of the sheet by the locking surface 43s of the leading end to correct the resist. Therefore, the gate stopper 43 is connected to an operating solenoid (not shown).

  A first roller 41b, a second roller 49, and a third roller 50 are disposed in pressure contact with each other in the second path 33, and a sheet discharge roller 67 is disposed in the sheet discharge path 37. Further, no sheet conveying mechanism is arranged in the first switchback path 34 and the second switchback path 35.

"Sheet edge detection sensor"
As shown in FIG. 2, the first sensor S <b> 1 that detects the edge of the sheet is disposed in the first path 32 described above, and the edge (leading edge and trailing edge) of the sheet carried into the first switchback path 34 is arranged. To detect. The second switchback path 35 is provided with a second sensor S2 for detecting the edge of the sheet to be carried.

  The first sensor S1 and the second sensor S2 detect the edge of the sheet in order to determine the fold position of the sheet, and the operation thereof will be described later together with the folding specification described later.

[Sheet conveyance control]
Therefore, the present invention is characterized in that the following control is performed when a sheet is fed from the carry-in entrance 30 to the first nip portion Np1.

"Assumed Configuration"
The first roller 41b, the first nip portion Np1 of the second roller 49, and the primary folding deflecting means 53 are disposed at the intersection K. A pair of paper feed rollers 41 is arranged on the first path 32 on the upstream side of the intersection K, and a sheet is placed in an upstream guide path (first switchback path) 34 located on the downstream side of the intersection K. No restraining conveying means is arranged. For this reason, a plurality of transport mechanisms do not interfere with each other to cause uneven transport speed.

  The primary folding deflection means 53 includes a driven roller 53a that is in pressure contact with the circumferential surface of the second roller 49 located downstream in the traveling direction of the sheet moving along the first path 32. The driven roller is a standby position Wp outside the path. To and from the operating position Ap in pressure contact with the circumferential surface of the roller.

  In such a configuration, the features of the present invention will be described with reference to FIG. As shown in the figure, the speed V1 for moving the driven roller 53a of the primary folding deflecting means 53 from the standby position Wp to the operating position Ap is set higher than the sheet speed V2 for moving the first path 32 (for example, V1 = 1. 7 × V2 speed setting).

  For this reason, the peripheral speed V2 of the pair of paper feeding and conveying rollers 41 and the lowering speed V1 of the elevating member 53c are set to V1> V2. This speed control controls the rotation speeds of the transport motor MF of the first roller 41b and the shift motor MS of the primary folding deflection member 53.

  The rotational speed control of the shift motor MS is shown in FIG. In FIG. 5A, the elevating member 53c is accelerated at a speed V1 from the top dead center (solid line in FIG. 5) to a point P3 where the driven roller 53a is in contact with the sheet fed through the first path 32, and the driven roller 53a is folded in the second time. A case will be described in which the roller 49 decelerates and stops after a predetermined time after contacting the roll 49. FIG. 5B shows a case where the elevating member 53c is stopped at the timing when the driven roller 53a contacts the second folding roll 49.

  The nip pressure between the pinch roller 41a and the first folding roll 41b at the pressure contact P1 shown in FIG. 5 is set to 4 kg. This is an optimum nip pressure when skew correction is performed on a sheet that has been loaded. The nip pressure between the driven roller 53a and the second folding roll at the pressure contact P2 is set to 1.5 kg. That is, by setting the sheet nip pressure at the pressure contact P1 to be larger than the sheet nip pressure at the pressure contact P2 (about 3 times in the illustrated apparatus), the sheet folding position is restricted to the pressure contact P1.

  As described above, the driven roller 53a descends in the direction perpendicular to the conveyance direction at the intersection K of the sheet fed out by the pair of sheet conveyance rollers 41 and nip conveyed only to the pair of sheet conveyance rollers 41. V1 is set faster than the sheet speed V2.

  For this reason, the movement displacement amount (ΔS1) of the sheet leading end portion in the upstream guide path (first switchback path) 34 is larger than the movement displacement amount (ΔS2) of the sheet trailing end portion fed out by the pair of sheet feeding and conveying rollers 41. .

  That is, as the driven roller 53a moves, the sheet moves with a larger displacement amount on the leading end side than on the trailing end side. As a result, the sheet is guided to the first nip Np1 on the basis of the pressure contact P1 of the pair of paper feeding and conveying rollers 41 at the rear end.

  At the same time, the friction load (conveyance load) of the upstream guide path (first switchback path) 34 acts on the leading edge of the sheet, so that the leading edge of the sheet is guided to the first nip Np1 by the driven roller 53a without shaking. The

  Further, the upstream guide path (first switchback path) 34 is formed in a curved path shape. As a result, the posture of the leading edge of the sheet fed to the path by the pair of sheet feeding and conveying rollers 41 does not fluctuate, and a guide that forms a curved path when the driven roller 53a is fed into the first nip portion Np1. The friction load (conveyance load) of the member acts greatly compared to the straight path.

  In FIG. 5, the pressure contact of the pair of paper feeding and conveying rollers 41 is P1, the contact of the driven roller 53a with the peripheral surface of the second roller 49 is P2, and the driven roller 53a is first in contact with the sheet moving in the first path 32. When the contact point is P3, the sheet conveyance length LS2 between P1 and P2 (the broken line length in FIG. 5) is set longer than the sheet conveyance length between P1 and P3 (LS1: see FIG. 5) so that LS2> LS1. .

  As a result, when the sheet fed by the pair of paper feeding and conveying rollers 41 is guided to the first nip portion Np1 by the driven roller 53a, LS2> LS1 is set and V1> V2 is set at the same time. The portion is not pulled from the pressure contact P1 of the pair of paper feeding and conveying rollers 41. Accordingly, the sheet is guided to the first nip portion Np1 based on the pressure contact P1 at the rear end.

Further, when the stroke from the contact point P3 to the contact point P2 is LS3, the speed is set so that the following equation is established.
(LS2−LS1) / V2≈LS3 / V1 (Formula 1)

  As a result, when the moving speed of the driven roller 53a is slow, the point (contact point) P3 in contact with the sheet is displaced. At the same time, sagging occurs in the sheet between the pressure contact P1 of the pair of paper feed rollers 41 and the driven roller 53a. It is possible to prevent the occurrence of folding misalignment, folding folds and the like due to the misalignment of the sheet engaging point and the sagging of the sheet.

  The second path 33 carries a sheet into an upstream guide path (first switchback path) 34 by a pair of carry-in rollers 40 and a registration roller (first roller) 41b arranged in the first path 32, and the first path 33 The second rollers 41b and 49 convey the sheet to the downstream side.

  The illustrated apparatus is characterized in that the sheet conveying mechanism disposed in the first and second paths 32 and 33 is simplified, and the apparatus is reduced in size, silence, and power consumption is reduced. Therefore, in the first path 32, a part of the outer periphery of the folding roller (first roller 41 b) arranged in the second path 33 faces the first path 32 between the carry-in roller pair 40 and the carry-out roller pair 62. It is arranged.

  A pinch roller 41 a is arranged on the outer periphery of the first roller 41 b, and the sheet sent from the carry-in roller pair 40 is sent to the first switchback path 34. As a result, it is not necessary to arrange a special transport roller in the first path 32, and the transport mechanism is simplified.

[Folding specification]
Next, a sheet folding method by the folding processing means 48 will be described with reference to FIG. A normal image-formed sheet may be folded in two or three with a margin for filing finish, or may be folded in two or three for letter finishing. In addition, when folding in three, there are cases where Z-folding and inner three-folding are performed. In FIG. 12, (a) shows an inner three fold, (b) shows a 1 / 3Z fold, and (c) shows a 1 / 4Z fold.

  In the case of folding in half, the sheet sent to the second path 33 is moved to the 1/2 position of the sheet size by the first second rollers 41b and 49, or the 1/2 position of the sheet edge is left at the end of the sheet. Fold together (primary fold).

  In the case of three-fold folding, the sheet sent to the second path 33 is 1/3 position of the sheet size by the first 2nd rollers 41b and 49 or 1/3 position of the sheet edge leaving a binding margin. Fold together (primary fold). The folded sheet is folded by the second third rollers 49 and 50 at the 1/3 position (secondary folding) and sent to the third path 36.

  In the case of three-fold folding, as shown in FIG. 12A, when the inner three-fold is performed, the sheet sent to the second path 33 is fed by the first second rollers 41b and 49 to the sheet rear end side 1/3. The positions are folded, and then the 1/3 position on the sheet front end side is folded.

  Similarly, at the time of 1 / 3Z folding, the sheet fed to the second path 33 is folded at the 1/3 position on the sheet leading end side by the first second rollers 41b and 49, and then the sheet 1/3 position on the sheet trailing end side is folded. Match.

  Further, in the case of three-fold folding, when the quarter position shown in FIG. 12C is Z-folded, the sheet fed to the second path 33 is fed by the first second rollers 41b and 49 to the sheet trailing edge side 1 / 4 positions are folded, and then the 1/2 position of the sheet is folded.

[Control means]
The control means 95 for folding the sheet is configured as follows. A control CPU is mounted on the sheet folding device B described above, or a folding processing control unit is provided in the control unit 91 of the image forming apparatus A. The control unit is configured so that the following operation is possible.

  First, stopper means (not shown) for restricting the position of the sheet leading edge to the first switchback path 34 and the second switchback path 35 of the second path 33, or sensor means (S1, S2 shown in the figure) for detecting the position of the sheet leading edge. Is provided.

  In the illustrated apparatus, the first sensor S1 is disposed in the first switchback path 34, and the second sensor S2 is disposed in the second switchback path 35. The control unit 95 is configured to calculate the timing at which the sheet fold position reaches a predetermined position based on the sheet size information sent from the image forming apparatus A and the detection signal from the sensor S1 (S2).

  Therefore, description will be made according to the control block diagram shown in FIG. In the image forming apparatus A, the controller panel 15 and the mode setting unit 92 are provided in the control CPU 91. The control CPU 91 controls the paper feeding unit 3 and the image forming unit 7 in accordance with the image forming conditions set on the controller panel 15.

  Then, the control CPU 91 transfers data and commands necessary for post-processing such as “post-processing mode”, “job end signal”, and “sheet size information” to the control means 95 of the post-processing apparatus C.

  The control means 95 of the post-processing apparatus C is a control CPU and includes a post-processing operation control unit 95a. The control CPU 95 receives detection signals from the first sensor S1 and the second sensor S2.

  Further, the control CPU 95 transmits “ON” and “OFF” control signals to the driving means (solenoid: not shown) provided in the gate stopper 43 and the path switching means 63.

  The control CPU 95 stores in the ROM 96 a folding process execution program for controlling the transport motor MF, the shift motor MS, the driving means, and the path switching means 63 so as to execute the folding specifications described above. The RAM 98 stores data for calculating the sheet crease by the crease position calculation means 97 and the operation timing time of the shift motor MS as data.

  The fold position calculation means 97 calculates a fold position (dimension) from the leading end of the sheet (distal end in the paper discharge direction) from the “sheet length size”, “folding specification”, and “binding margin dimension”. It consists of For example, in the two-fold mode, the sheet is folded at a half position in the paper discharge direction, or folded at a half position leaving a preset binding margin. The crease position is calculated by, for example, [{(sheet length size) − (binding margin)} / 2].

  In the three-fold mode, the fold position is calculated according to the folding specifications such as letter fold (inner fold, 1 / 3Z fold), filing fold (1 / 4Z fold, 1 / 3Z fold).

[Folding operation]
The operation of the configuration of the sheet folding apparatus B will be described. FIG. 7A shows a state where the sheet entering the carry-in entrance 30 is corrected for registration, and FIG. 7B shows a state where the sheet is carried into the first switchback path 34 for primary folding.

  8A shows a state where the driven roller 53a is in contact with the sheet, FIG. 8B shows a state where the sheet is folded at the first folding position Np1, and FIG. 9A shows the second switchback path 35. FIG. 9B shows a state in which the folded sheet is carried in, FIG. 9B shows a state in which the driven roller 54a is in pressure contact, FIG. 10A shows a state in which the sheet is folded at the secondary folding position Np2, and FIG. The state of unloading is shown respectively.

  In FIG. 7A, the sheet is guided to the carry-in entrance 30 and is sent downstream by the carry-in roller pair 40. At this time, the control means 95 controls so that the gate stopper 43 is positioned at the locking position. Then, the leading end of the sheet is locked to the locking surface 43s of the stopper member and is bent and deformed in a loop shape within the registration area. At this time, the sheet is aligned at the leading edge along the locking surface 43s. Next, the control means 95 retracts the gate stopper 43 from the locking position to the standby position.

  In FIG. 7B, the control means 95 moves the gate stopper 43 from the locking position to the standby position. Then, the sheet is sent downstream in the first path 32 by the above-described sheet conveying mechanism. Then, the control means 95 controls the path switching means 63 to guide the sheet from the first path 32 to the first switchback path 34 as shown in the figure.

  Then, the sheet is carried into the first switchback path 34 by the sheet feeding / conveying means 41. In the first path 32, a first sensor S1 is disposed on the downstream side of the pinch roller 41a and the first roller 41b, and detects the leading edge of the sheet carried into the first switchback path 34.

  In FIG. 8A, the control means 95 moves the elevating member 53c of the primary folding deflecting means 53 at the timing when the fold position of the sheet is transferred to a predetermined position based on the signal detected by the first sensor S1. Move from the standby position to the operating position. In this process, the driven roller 53a contacts the sheet.

  By setting the moving speed of the driven roller 53a to be higher than the sheet conveying speed sent from the first path 32, the sheet is conveyed when the driven roller 53a is guided to the nip portion Np1 of the pair of folding rollers. It does not occur.

  Then, the driven roller 53a is brought into contact with the contact P2 in contact with the peripheral surface of the second roller 49 without shifting the contact point P3 where the conveyed sheet and the driven roller 53a first contact, so that the sheet is not wrinkled. An accurate folding position can be positioned at the roller nip portion.

  In FIG. 8B, the sheet in the first path 32 is deformed into a V shape toward the first nip portion Np1. When the driven roller 53a attached to the elevating member 53c comes into pressure contact with the peripheral surface of the second roller 49, the leading end of the sheet is fed out in the opposite direction (the rotation direction of the second roller 49).

  On the other hand, the sheet rear end side feeds the sheet toward the first nip portion Np1 by the conveying force of the pinch roller 41a and the first roller 41b. At this time, the curved guide surface of the curved guide 53b regulates the sheet along the circumferential surface of the roller along the circumferential surface of the first roller 41b.

  Accordingly, the sheet is fed to the primary folding position Np1 at the leading end side thereof by the driven roller 53a, the trailing end side thereof by the pinch roller 41a and the first roller 41b toward the first nip portion Np1, and the elevating timing of the elevating member 53c is determined. The crease position will be determined.

  Therefore, the control means 95 determines the speed at which the sheet is transferred by the pinch roller 41a and the first roller 41b, and the timing at which the driven roller 53a moves from the standby position to the operating position (particularly, the driven roller 53a contacts the peripheral surface of the second roller 49). (Timing) is previously set to an optimum value by experiment.

  Since the curved guide surface of the curved guide 53b guides the sheet along the peripheral surface of the opposing first roller 41b in synchronization with the movement of the driven roller 53a from the standby position to the operating position, the sheet fold position However, there is no fear of changing each time.

  In FIG. 9A, a sheet that has been folded at the first nip portion Np1 at the 1/2 position (folded), 1/3 position (trifold), and 1/4 position (trifold) is the first nip. The conveyance force is applied at the part Np1 and the sheet is sent downstream.

  Therefore, the control means 95 positions the elevating member 54c of the secondary folding deflecting means 54 in the operating position in the two-fold mode and in the standby position in the three-fold mode.

  The figure shows the control in the tri-fold mode. When folding in half, the elevating member 54c is positioned at the operating position, and the folded sheet is guided from the leading end to the second nip portion Np2 and sent to the carry-out port 31 on the downstream side.

  Therefore, in the three-fold mode, the control means 95 positions the elevating member 54c of the secondary folding deflecting means 54 at the standby position as shown in FIG. Then, the sheet sent from the first nip portion Np1 is sent to the second switchback path 35 from the leading edge. Then, the second sensor S2 detects the leading end (fold position) of the sheet.

  In FIG. 9B, the control means 95 moves the elevating member 54c of the secondary folding deflecting means 54 from the standby position when the secondary folding position reaches the predetermined position based on the detection signal of the second sensor S2. Move to operating position. Then, the sheet in the second switchback path 35 is fed out in the opposite direction when the driven roller 54a comes into contact with the peripheral surface of the third roller 50.

  As a result, as shown in FIG. 10A, the leading edge of the sheet is driven by the driven roller 54a, and the trailing edge is fed by the first nip portion Np1 in the opposite direction to guide it to the second nip portion Np2. In this case, the movement timing of the elevating / lowering member 54c from the standby position to the operating position is the same as in the case of the primary folding deflecting means 53 described above, and the operation of the guide member 54b is also the same.

  In FIG. 10B, the folded sheet sent to the second folding position Np <b> 2 is reliably folded by the additional folding roller 64 pressed against the second roller 49 and transferred to the third path 36. Therefore, the control means 95 sends the folded sheet to the paper discharge path 37 or returns it to the first path 32 according to a preset sorting specification.

  The illustrated apparatus controls the path switching flapper 66 and guides it from the sheet discharge path 37 to the storage stacker 65 in the case of letter folding specifications of three-fold folding and 1 / 3Z-folding, which need not be bound by the post-processing apparatus C. To do.

  Further, in the three-fold mode such as bi-folding or 1 / 4Z-folding that requires post-processing such as filing or bookbinding and binding processing, the paper is transferred from the third path 36 to the first path 32, and the post-processing device 31 is transferred from the carry-out port 31. Send to C.

[Folding operation in bi-fold mode]
In the folding operation described above, in the mode in which the sheet is folded in half, as shown in FIG. 14, a mode instruction signal as to whether or not to perform folding processing is received from the image forming apparatus A (St01). Then, the control means 95 calculates the crease position by the crease position calculation means 97 (St02). Therefore, in the folding unit mode (St03), the control unit 95 detects the leading edge of the sheet (St04) in the first sensor S1.

  The primary folding deflecting means 53 is moved from the standby position to the operating position after the passage of the sheet feeding time corresponding to the length of the sheet calculated by the fold position calculating means 97 from this detection signal (St05) (St06). This movement is controlled by the rotation of the shift motor MS.

  In the process in which the elevating member 53c of the primary folding deflector 53 moves to the operating position, the sheet of the first path 32 is distorted toward the first nip portion Np1 with reference to the fold position as described with reference to FIG. 8B. Is done. When the driven roller 53a of the primary folding deflecting means 53 comes into contact with the peripheral surface of the second roller 49, the sheet is dragged and inserted into the first nip portion Np1 from the fold position.

  At this time, in the bi-fold mode, the control means 95 moves the secondary folding deflecting means 54 after the expected time (St07) when the sheet fold is inserted into the first nip portion Np1 with reference to the detection signal from the first sensor S1. It moves to the operating position (St08). This estimated time is set to a time before the fold position of the sheet is inserted into the first nip portion Np1 and the leading end of the folded sheet reaches the curved guide 54b.

  Therefore, the leading edge of the folded sheet is guided by the curved guide surface of the curved guide 54b in the state shown in FIG.

  At the same time, since the driven roller 54a located at the operating position rotates following the rotation of the third roller 50, even if the leading edge of the folded sheet is curled away from the second nip portion Np2, the driven roller 54a As the third roller 50 rotates, it is reliably guided to the second nip portion Np2.

  Accordingly, the control means 95 carries out the folded sheet carried out from the second nip portion Np2 to the third path 36 to the first path 32 from the third path 36. Then, the control means 95 prepares for the subsequent sheet processing with the secondary folding deflecting means 54 positioned at the operating position (St09).

  In the figure, the primary folding deflecting means 53 is positioned at the standby position, and the secondary folding deflecting means 54 that moves in the opposite direction is positioned at the operating position. It is also possible to configure so that the secondary folding deflecting means 54 is moved to the standby position by the detection signal of the paper sensor S3.

[Folding operation in three-fold mode]
In the mode in which the sheet is folded in three, as described with reference to FIGS. 8 to 10, a mode instruction signal indicating whether or not to fold the sheet is received simultaneously from the image forming apparatus A (St01). Then, the control means 95 calculates the crease position by the crease position calculation means 97 (St02). Therefore, in the control unit 95, in the tri-fold mode (St10), the first sensor S1 detects the leading edge of the sheet (St11).

  The primary folding deflecting means 53 is moved from the standby position to the operating position after the passage of the sheet feeding time corresponding to the length of the sheet calculated by the fold position calculating means 97 from the detection signal (St12) (St13). This movement is controlled by the rotation of the shift motor MS.

  In the process in which the elevating member 53c of the primary folding deflector 53 moves to the operating position, the sheet of the first path 32 is distorted toward the first nip portion Np1 with reference to the fold position as described with reference to FIG. 8B. Is done.

  When the driven roller 53a of the primary folding deflecting means 53 comes into contact with the peripheral surface of the second roller 49, the sheet is dragged and inserted into the first nip portion Np1 from the fold position. At this time, the control means 95 waits for the second sensor S2 to detect the leading edge of the sheet in the trifold mode (St14).

  Based on the signal that the second sensor S2 has detected the leading edge of the sheet, the control means 95 moves the secondary folding deflecting means 54 to the operating position after the expected time that the secondary fold position of the sheet reaches the predetermined position (St15). (St16). This estimated time is set by the calculated value of the crease position calculating means 97. Therefore, the sheet is inserted into the second nip portion Np2 with a conveying force applied from the driven roller 54a. The front end of the sheet is detected by the paper discharge sensor S3 and is carried out from the third path 36 to the first path 32 according to the folding specification, or is carried out from the paper discharge path 37 to the storage stacker 65 (St17).

[Output path configuration]
The folded sheets folded in half as described above are sent to the third path 36 from the pressure contacts of the second and third rollers 49 and 50. Then, the sheet is further folded by an additional folding roller 64 in pressure contact with the second roller 49 and guided to the third path 36.

  The third path 36 joins the first path 32 as described above. Branching from the third path 36, a paper discharge path 37 is continuously provided via a path switching flapper 66, and this paper discharge path 37 guides the folded sheet to a storage stacker 65 disposed below the second path 33. To do. This paper discharge path is configured as described above with a curvature R3. Reference numeral 67 in the figure denotes a paper discharge roller disposed in the paper discharge path 37.

  Therefore, sheets that are folded into letter specifications such as inner three-fold or 1 / 3Z-fold that do not need to be transferred to the post-processing apparatus C are accommodated in the storage stacker 65 without being transferred to the carry-out port 31.

  Of the folded sheets sent to the third path 36, the sheet to be transferred to the post-processing apparatus C and to be post-processed is transferred toward the outlet 31 by the pair of discharge rollers 62. In this case, the determination as to whether or not to perform post-processing is configured such that, for example, the controller panel 15 sets the post-processing conditions simultaneously with the image forming conditions. Then, it is configured to be carried out to the storage stacker 65 or to be transferred to the post-processing apparatus C according to the set finishing conditions.

[Image forming apparatus]
The image forming apparatus A has the following configuration as shown in FIG. This apparatus sends a sheet from the sheet feeding unit 3 to the image forming unit 7, prints the sheet on the image forming unit 7, and then carries out the sheet from the main body discharge port 18. The sheet feeding unit 3 stores sheets of a plurality of sizes in sheet feeding cassettes 4 a and 4 b, and separates designated sheets one by one and feeds them to the image forming unit 7. The image forming unit 7 includes, for example, an electrostatic drum 8, a print head (laser light emitting device) 9 and a developing device 10 arranged around the electrostatic drum 8, a transfer charger 11, and a fixing device 12. An electrostatic latent image is formed by the light emitting device 9, toner is attached to the developing device 10, an image is transferred onto the sheet by the transfer charger 11, and heat fixing is performed by the fixing device 12.

  The sheets on which images are formed in this way are sequentially carried out from the main body discharge port 18. 13 is a circulation path. The sheet printed on the front side from the fixing device 12 is turned upside down through the main body switchback path 14 and then fed again to the image forming unit 7 to be printed on the back side of the sheet. This is the path for duplex printing. The sheet printed on both sides in this way is turned upside down by the main body switchback path 14 and then carried out from the main body discharge port 18.

  An image reading unit 20 shown in FIG. 1 scans an original sheet set on the platen 21 with a scan unit 22 and electrically reads it with a photoelectric conversion element (not shown). The image data is digitally processed by an image processing unit, for example, and then transferred to the data storage unit 16 to send an image signal to the laser emitter 9. Reference numeral 25 denotes a feeder device that feeds a document sheet stored in the stacker 26 to the platen 21.

  The image forming apparatus A having the above-described configuration is provided with a control unit (controller) (not shown), and image forming conditions such as sheet size designation, color / monochrome printing designation, print number designation, single-sided / double-sided printing designation, and enlargement from the controller panel 15. -Printout conditions such as reduced print designation are set.

  On the other hand, in the image forming apparatus A, image data read by the scan unit 22 or image data transferred from an external network is accumulated in the data storage unit 16, and the image data is transferred from the data storage unit 16 to the buffer memory 17. The data signal is sequentially transferred from the buffer memory 17 to the print head 9.

  From the controller panel 15, the post-processing conditions are also input and designated simultaneously with the image forming conditions. As the post-processing conditions, for example, “print-out mode”, “staple binding mode”, “sheet bundle folding mode”, or the like is selected. As the post-processing conditions, the folding specifications in the sheet folding apparatus B described above are set.

[Post-processing equipment]
The post-processing apparatus C has the following configuration as shown in FIG. This apparatus includes a sheet receiving port 69, a sheet discharge stacker 70, and a post-processing path 71 in an apparatus housing 68. The sheet receiving port 69 is connected to the carry-out port 31 of the above-described sheet folding apparatus B, and is configured to receive a sheet from the first conveyance path 32 or the third conveyance path 36.

  The post-processing path 71 is configured to guide the sheet from the sheet receiving port 69 to the paper discharge stacker 70, and a processing tray 72 is provided in this path. Reference numeral 73 in the drawing denotes a paper discharge port for collecting sheets from the post-processing path 71 on a processing tray 72 arranged on the downstream side. A punch unit 74 is disposed in the post-processing path 71. A paper discharge roller 75 is disposed at the paper discharge port 73, and sheets from the sheet receiving port 69 are stacked on the processing tray 72.

  The processing tray 72 switches back the sheet from the post-processing path 71 (conveying direction reverse) and collects and aligns it on a rear end regulating member (not shown) provided on the tray. For this reason, a forward / reverse roller 76 for switching back the sheet from the sheet discharge port 73 is provided above the tray. Further, the processing tray 72 is connected to the paper discharge stacker 70, and the sheet from the paper discharge port 73 is supported by the paper discharge stacker 70 at the front end side and the processing tray 72 at the rear end side (bridge support).

  The processing tray 72 is provided with a staple unit 77 for binding the sheet bundle positioned on the trailing edge regulating member. The sheet bundle stacked on the tray 72 is stapled and then conveyed to the paper discharge stacker 70. The illustrated stacker 70 is provided with an elevator mechanism (not shown) that moves up and down according to the amount of stacked sheets.

B Sheet folding device K Intersection 3 Feeder 30 Carry-in entrance (carry-in part)
31 Unloading port (unloading part)
32 First transport path (first path)
33 Second transport path (second path)
34 First switchback path (upstream guide path)
35 Second switchback path (downstream guide path)
36 Third transport route (third route)
37 Paper discharge path 40 Carry-in roller pair 41 Paper feed / conveying means (paper feed / conveying roller pair)
41a Pinch roller 41b First roller 43 Gate stopper 49 Second roller 50 Third roller 53 Primary folding deflecting means 53a Followed roller 54 Secondary folding deflecting means 54a Followed roller 63 Path switching means 65 Storage stacker 85a Actuating lever 85b Pulley 85c Transmission belt 85d Spring clutch (torque limiter)
85x Support shaft 86a Spring clutch Np1 First folding position (first nip position)
Np2 second folding position (second nip position)
S1 1st sensor S2 2nd sensor V1 Movement speed (lowering speed) of the deflecting member
V2 Sheet transport speed

Claims (10)

An apparatus for folding a sheet from a carry-in unit and carrying it out to a carry-out unit,
A first conveyance path for guiding the sheet from the carry-in unit to the carry-out unit without folding the sheet,
A second conveyance path arranged in a direction intersecting with the first conveyance path and folding the sheet;
A pair of folding rollers disposed in the second conveyance path for folding the sheet;
Folding deflecting means for inserting the fold position of the sheet into the nip portion of the pair of folding rollers;
With
The second transport path is
An upstream guide path that branches from the intersection with the first conveyance path and guides the leading edge of the sheet;
A downstream guide path for guiding the sheet downstream from the intersection,
Consists of
The pair of folding rollers is
Arranged at the intersection of the first transport path and the second transport path,
The folding deflection means includes
A driven roller in pressure contact with the circumferential surface of the pair of folding rollers located on the downstream side in the traveling direction of the sheet moving along the first conveying path;
Shift means for moving the driven roller between a standby position where the driven roller is retracted from the nip portion of the pair of folding rollers and an operating position for guiding the sheet to the nip portion;
Consists of
The sheet folding apparatus according to claim 1, wherein the shift means is set so that the speed at which the driven roller is moved from the standby position to the operating position is faster than the sheet speed at which the first conveying path is moved. In the first transport path, a paper feed transport unit that feeds the sheet toward the intersecting portion is disposed,
The shifting means is
The driven roller is moved from the standby position to the operating position at a higher speed than the sheet conveying speed by the sheet feeding and conveying means,
The leading edge of the sheet is carried into the upstream guide path by the conveying force applied by the sheet feeding / conveying means, and is conveyed toward the nip portion of the folding roller pair by moving the driven roller from the standby position to the operating position. The sheet folding apparatus according to claim 1. The upstream guide path of the first transport path is configured to apply a transport load to the sheet,
A sheet leading end is carried into the upstream guide path by the sheet feeding and conveying means,
3. The sheet folding apparatus according to claim 2, wherein a sheet leading end portion is carried out from an upstream guide path by the driven roller that is driven in pressure contact with a circumferential surface of the folding roller pair. The paper feeding / conveying means is composed of a pair of rollers pressed against each other,
The peripheral speed of the roller pair is set to be substantially the same as the peripheral speed of the folding roller pair,
The sheet folding apparatus according to claim 2 or 3, wherein a sheet pressing force of the sheet feeding / conveying means is set to be larger than a sheet pressing force between the driven roller and the circumferential surface of the folding roller. At least a part of the circumferential surface of the folding roller pair is disposed at a position facing the first transport path,
5. The sheet folding apparatus according to claim 4, wherein the sheet feeding / conveying means comprises a part of the circumferential surface of the folding roller pair and a pinch roller pressed against the circumferential surface. The pressure contact of the roller pair constituting the sheet feeding / conveying means is P1,
P2 is a contact point where the driven roller is in contact with the peripheral surface of the folding roller pair;
The contact point at which the driven roller first comes into contact with the sheet moving on the first conveyance path is P3,
And when
The sheet folding apparatus according to claim 4, wherein the sheet conveyance length between P1 and P2 is set longer than the sheet conveyance length between P1 and P3. V1 is a speed at which the driven roller moves from the standby position to the operating position.
V2 is a speed at which the sheet feeding / conveying means conveys the sheet,
The sheet conveyance length between P1 and P2 is L1,
The sheet conveyance length between P1 and P3 is L2,
LS represents a moving distance between the position where the driven roller contacts the folding roller peripheral surface from the position where the driven roller first contacts the sheet moving on the first conveyance path,
And when
(L2-L1) / V2≈LS / V1
The sheet folding apparatus according to claim 6, wherein the relationship is as follows. The deflecting means, together with the driven roller,
The sheet folding apparatus according to claim 1, further comprising: a curved guide that guides the sheet along a circumferential surface of a folding roller that is positioned on an upstream side in a traveling direction of the sheet moving along the first conveyance path. The downstream guide path of the first transport path is configured as a curved path curved in an arc shape,
The sheet folding apparatus according to claim 3, wherein the sheet from the carry-in unit is transferred to the carry-out unit through a substantially S-shaped conveyance path from the upstream guide path to the downstream guide path. In the carry-in part, an image forming part for forming an image on the sheet is arranged on the upstream side,
The sheet folding apparatus according to claim 1, wherein a sheet storage unit that stacks and stores sheets is disposed on the downstream side of the carry-out unit.

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