JP2012140207A - Sheet folding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet folding device simple in structure by which a sheet can be folded at an accurate folding position.SOLUTION: The sheet folding device includes a folding roller 41 and a folding roller 49 for forming a folding line on the sheet. The folding roller 41 is disposed at a position where the sheet is transported on the transport route while the folding roller 49 is disposed downstream and below the folding roller 41 on the transport route. Furthermore, a driven roller 53a which moves downward to the operation position near the nip position of the sheet with which the peripheral faces of the folding-roller pair 41 and 49 contact so as to contact with the peripheral face of the folding roller 41 when creasing the sheet is additionally provided. Thus, the sheet is guided to the nip of the folding rollers 41 and 49 by the contact of the roller 49 with the driven roller 53a.

Description

  The present invention relates to a sheet folding apparatus that folds an image-formed sheet, and more particularly to a sheet folding apparatus having a simple structure that folds a sheet at an accurate crease position.

  2. Description of the Related Art Conventionally, a sheet folding apparatus that performs a finishing process by folding a sheet on which an image is formed by an image forming apparatus such as a printing machine, a printer apparatus, or a copying machine at a predetermined folding position is known. For example, in Patent Document 1, a first folding roller and a second folding roller that are in contact with each other along the conveyance path and rotate in reverse are provided on the downstream side in the conveyance direction of the paper. A first driven roller that can be brought into contact with and separated from the roller, a second driven roller that can be brought into and out of contact with the second folding roller, and a second conveyance path disposed downstream of the second folding roller. The first folding roller is rotated in the transport direction, the second folding roller is rotated in the return direction, the second driven roller is separated from the second folding roller, and the leading edge of the sheet is sent to the second transport path. Thereafter, there has been proposed a sheet folding apparatus in which a second driven roller is brought into contact with a second folding roller and the first folding roller and the second folding roller perform a first folding process on the sheet.

  In Patent Document 2, a pair of folding rollers are arranged in parallel with each other so as to be able to rotate inward with respect to the sheet conveyance path, and a nip is formed in which a nip is formed between the pair of folding rollers to sandwich and fold the sheet. A roller unit and sheet pushing means for curving the conveyed sheet so as to be wound into the nip are provided, and the conveyed sheet is guided to the nip along the folding roller on the upstream side of the sheet conveyance by the pushing means. A sheet folding apparatus has been proposed.

  Further, Patent Document 3 discloses a sheet deflection mechanism that inserts a sheet crease at a nip position of a pair of folding rollers in a folding device that forms folds that are continuous in a bellows shape on the sheet. There is known a deflection mechanism that guides the crease position to a nip point by moving a driven roller in contact with the surface to the nip position from the outside of the sheet conveyance path.

JP 2005008337 A JP 2010-089853 A JP 2006-335500 A

  As described above, a sheet folding apparatus that folds a sheet sent to the conveyance path by inserting the sheet at the nip point of a pair of folding rolls and inserting the fold position with a sheet deflecting member is known from Patent Documents 1, 2, and 3 and the like. ing. In this case, it is also known that if the crease position of the sheet guided by the sheet deflection member is displaced, the finishing quality is greatly affected.

  However, since all of the conventional folding devices have the pair of folding rollers arranged in parallel along the sheet conveying direction, the conveyed sheet is greatly curled outwardly from the conveying direction. In this case, the leading edge of the sheet may be caught by the downstream folding roller, which may cause sheet damage or sheet jam.

  Further, when the sheet deflecting member is made to act on the sheet on the horizontal conveyance path to bring the downstream folding roller into contact with the sheet, the amount of bending of the sheet is small, so that the sheet slips and cannot be smoothly conveyed to the folding position. There is a point. In particular, since thick paper is stiff, even if the downstream folding roller is slightly lowered from the horizontal conveyance path, a sufficient amount of bending cannot be obtained and the sheet may slip.

  If the nip pressure of the driven roller is increased as a measure for eliminating such sheet slippage, a considerable amount of electric power is required to separate the driven roller.

  Also, in terms of space, the conventional folding apparatus in which the pair of folding rollers is arranged in parallel along the sheet conveying direction has a drawback that the apparatus becomes large by taking a space in the width direction.

  According to the present invention, even if a sheet to be conveyed is greatly bent downward due to a curl or the like, a jam or the like does not occur, and a sufficient amount of sheet bending can be secured and the sheet can be reliably folded at a correct crease position. An object of the present invention is to provide a sheet folding device that can be used.

  By the way, the sheet deflection member for inserting a sheet into the nip portion includes a mechanism that guides to a nip point by a plate member such as a knife blade as shown in Patent Documents 1 and 2, and a driven roller as shown in Patent Document 3. A mechanism is known in which the sheet is slidably contacted with the peripheral surface of the folding roller and guided to the nip point.

  The present invention intends to solve the above-described problem in a sheet folding apparatus employing a driven roller similar to that of Patent Document 3.

  As a problem of such a sheet folding apparatus using a driven roller, Patent Document 3 advances the driven roller from the same sheet conveying direction to the nip point of the folding roller arranged in parallel along the sheet conveying direction. Therefore, not only does the advancing path of the driven roller become long, but an arc-shaped advancing path must be set so as not to interfere with the conveyed sheet, and there is a disadvantage that the mechanism becomes complicated and large.

  Accordingly, another object of the present invention is to provide a sheet folding apparatus using a driven roller with a simple configuration.

  In order to achieve the above object, the present invention provides a sheet folding processing unit disposed in a sheet conveyance path, the first folding roller disposed at a position for conveying the sheet in the conveyance path, and the first folding roller. A second folding roller that contacts the outer circumferential surface of the first folding roller and rotates in the opposite direction; and a nip position of the sheet that contacts the outer circumferential surface of the folding roller pair when folding the sheet. A driven roller in contact with the outer peripheral surface of the second folding roller at a nearby operating position; and a shift means for reciprocating the driven roller between a standby position above the transport path and the operating position; The second folding roller is disposed downstream and below the first folding roller in the transport path, and the operating position is a distance from the transport path of the rotation shaft of the first folding roller. And, characterized in that that which is set at a position further away downward.

  In addition, a curved guide for guiding the sheet to be folded along the outer peripheral surface of the first folding roller to the nip position of the sheet is further provided.

  The operating position of the driven roller is set in the vicinity of a tangent line between contacts that contact each outer peripheral surface of the folding roller pair on the operating position side.

  The operating position of the driven roller is set so that a folding angle of the sheet when folding is performed at the operating position is 90 degrees or less.

  At this time, sheet guide means for supporting the folding angle of the sheet to 90 degrees or less is further provided.

  The shift means is characterized in that a speed at which the driven roller is moved from the standby position to the operating position is set to be higher than a sheet speed at which the conveying path is moved.

  The conveyance path is disposed so as to intersect the first conveyance path, a first conveyance path for carrying out the sheet carried in from the sheet carry-in port to the sheet carry-out port side without folding processing, and the sheet from the sheet carry-in port. A second conveyance path configured to fold the sheet, and the second conveyance path includes a path end portion that guides the sheet to the folding roller pair nip portion, and a path that guides the folded sheet to the downstream side. An end portion is disposed in an area facing the first conveyance path, and the sheet guide is provided at an intersection of the first conveyance path and the second conveyance path. A first guide posture position for guiding the sheet from the end of the second conveying path toward the nip position; and a second guide posture position for guiding the sheet from the sheet carry-in port toward the sheet carry-out port. Are movable in between, it is characterized in that.

  In the present invention, one of the pair of folding rollers is disposed at a position for conveying a sheet, and the other roller is disposed on the downstream side and in the lower side in the sheet conveying direction. However, the problem of jamming by being caught by the folding roller or not reaching the nip position by both rollers due to insufficient amount of bending of the sheet when the sheet is folded is eliminated. The driven roller has a short reciprocating path for reciprocating in the direction perpendicular to the sheet conveying direction with respect to the folding roller disposed downstream and downward in the sheet conveying direction, and for simple vertical movement. The mechanism is also simplified.

  Further, by arranging the pair of folding rollers with a difference between the upper and lower sides, it is possible to realize a device layout that makes the device compact and compact.

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 diagrams of a drive mechanism of a path switching unit in the apparatus of FIG. 2, in which FIG. 2A illustrates 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 deflection | deviation member, (a) shows the speed of a shift motor, (b) shows the speed of a deflection | deviation 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. Explanatory drawing of the arrangement | positioning relationship between a deflection | deviation means and a bending deflection | deviation means. Operation | movement explanatory drawing of a deflection | deviation means. Explanatory drawing of the folding deflection | deviation means of this invention being effective in the jam prevention of a sheet | seat. Explanatory drawing of conveying while reducing the waist of a sheet | seat by the deflection | deviation means and folding deflection | deviation means of this invention. Explanatory drawing of the arrangement | positioning relationship of a deflection | deviation means, a folding deflection | deviation means, and a path | route switching means.

  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 sheet folding apparatus B is shown in FIG. 2 in its entire configuration, but the apparatus housing 29 is provided with a sheet carry-in port 30 and a sheet carry-out port 31. At the continuous position, the sheet carry-out port 31 is disposed at a position continuous with the sheet receiving port 69 of the downstream side post-processing apparatus C. In the present invention, the sheet folding apparatus B may be built in the casing of the post-processing apparatus C without including the independent apparatus housing 29. In that case, the sheet carry-in port 30 and the sheet carry-out port 31 are provided. do not need. Therefore, hereinafter, the sheet carry-in port 30 is synonymous with the carry-in unit, and the sheet carry-out port 31 is synonymous with the sheet carry-out unit. For convenience of explanation, the sheet carry-in unit is described as the sheet carry-in port 30 and the sheet carry-out unit is described as the sheet carry-out port 31. To do.

  As shown in FIG. 2, the sheet carry-in port 30 and the sheet carry-out port 31 are disposed so as to cross the apparatus housing 29, and the illustrated sheet carry-in port 30 and the sheet carry-out port 31 are disposed at positions that are substantially opposed in the horizontal direction. Has been. Between the sheet carry-in port 30 and the sheet carry-out port 31, a first conveyance path 32 for carrying out the sheet from the sheet carry-in port 30 to the sheet carry-out port 31 without folding processing, and a sheet from the sheet carry-in port 30. A second conveyance path 33 for folding the sheet and carrying it out to the sheet carry-out port 31 is arranged. 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 conveyance path 32 is disposed in the apparatus housing 29 between the sheet carry-in port 30 and the sheet 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. The first conveying path 32 guides the sheet from the sheet carry-in port 30 to the sheet carry-out port 31 without being folded as described above.

  The second conveying path 33 is configured as a path for folding the sheet from the sheet carry-in entrance 30. For this reason, the sheet is branched from the first conveyance path 32 to guide the sheet from the sheet carry-in entrance 30 to the folding positions (nip position; hereinafter the same) Np1 and Np2. At the same time, the second transport path 33 is arranged in a direction intersecting the first transport path 32 as shown in FIG. 2, and a first folding position Np1 and a second folding position Np2 are set in this path. The second transport path 33 includes a first switchback path 34 for guiding the leading edge of the sheet for primary folding to the first folding position Np1, and a second folding of the folded sheet leading edge for secondary folding of the folded sheet. The second switchback path 35 guides to the position Np2.

  Thus, the second conveyance path 33 is arranged in a direction intersecting the first conveyance path 32, and the first switchback path 34 is arranged in the upper area of the first conveyance path 32, and the sheet is conveyed downstream from the intersection K in the lower area ( A second switchback path 35 that moves in the direction of the second folding position 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 conveyance 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 transferred to the sheet carry-out port 31. The 3rd conveyance path | route 36 which carries out toward is continuously provided.

  The first conveyance path 32 and the second conveyance 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 located below the first conveyance path 32. The second switchback path 35 for guiding the folded sheet to the downstream side may be disposed above the first conveyance path 32. 2, the first transport path 32 is arranged in the horizontal direction. However, when the path is arranged in the apparatus housing 29 in the vertical direction, the first switch back path 34 and the second switch back path 35 are arranged in the first direction. It is also possible to arrange it opposite to the left and right areas of the transport 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 conveyance path 36 that guides the folded sheet to the sheet carry-out port 31 is connected to the second conveyance path 33. The illustrated third conveyance path 36 is provided between the second folding position Np <b> 2 where the sheet is secondarily folded and the sheet carry-out port 31. A paper discharge path 37 for guiding the folded sheet from the paper discharge outlet 51 different from the sheet carry-out port 31 to the storage stacker 65 is disposed in the third transport path 36.

  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. The paper discharge path 37 connected to the third transport path 36 is also configured as a circularly curved path having a curvature R3.

  The path length (L1) of the first switchback path 34 for guiding the sheet from the first conveyance path 32 to the first folding position Np1, and the first folded sheet for guiding the folded sheet to the second folding position Np2. The path length (L2) of the second switchback path 35 is configured such that the path length L1> the 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 Np1 is arranged in the vicinity of the first transport path 32, each path length becomes L3 <L2 <L1, resulting in a compact path configuration.

  Thus, the first switchback path 34 having the longest path length is disposed above the first transport path 32 and the second switchback path 35 having a short path length is disposed below, and similarly below the first transport path 32. A paper discharge path 37 is disposed, and a storage stacker 65 is disposed below the paper discharge path 37. Accordingly, the first switchback path 34 having a long path length is disposed in the upper area of the first transport 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 path switching means 63 is disposed at the intersection K between the first transport path 32 and the second transport path 33 described above. The path switching means 63 will be described with reference to FIG. 3. The sheet fed from the first transport 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 ( (A solid line in the figure) or a guide (broken line in the figure) to the sheet carry-out port 31 or the path is switched.

  A sheet guide 61 is provided at an intersection K between the first conveyance path 32 and the second conveyance path 33. The sheet guide 61 is disposed between the first roller 41 and the pair of carry-out rollers 62 a and 62 b in the first conveyance path 32, and guides the sheet sent from the first conveyance path 32 to the first switchback path 34. A shaft is supported so as to be swingable between (solid line in the figure) and a posture (broken line in the figure) for guiding to the sheet exit 31.

  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 across the path switching means 63 in the direction of guiding the sheet toward the second transport path 33.

  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 sheet is moved to the second transport path). Positioning to 33). 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 transport 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 of guiding the sheet to the sheet 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 sheet carry-out port 31).

"Folding roller configuration"
As shown in FIGS. 2 and 3, a folding roller mechanism composed of a pair of folding rollers is disposed in the second transport path 33. The first roller 41, the second roller 49, and the third roller 50 are disposed so as to be in pressure contact with each other at the intersection K between the first conveyance path 32 and the second conveyance path 33 (see FIG. 3). A first folding position Np1 is formed at the pressure contact between the first roller 41 and the second roller 49, and the sheet is second folded at the pressure contact between the second roller 49 and the third roller 50. A folding position Np2 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, which is the first folding roller, is arranged at a position where a part of the outer periphery faces the first conveying path 32, that is, a position where the sheet is conveyed in the first conveying path 32. There is a pinch roller (floating roller) 42 in pressure contact with the peripheral surface of the roller. The first roller 41 and the pinch roller 42 that are in pressure contact with each other constitute a sheet feeding / conveying means of the first conveying path 32, whereby the sheet from the sheet carry-in entrance 30 is conveyed downstream.

  The second roller 49 that is the second folding roller is disposed on the downstream side and below the first roller 41 that is the first folding roller in the first transport path 32.

[Configuration of folding deflection means]
As described above, the folding roller composed of the three rollers (41, 49, 50) has the primary folding deflection means 53 at the first folding position Np1 and the secondary folding deflection means 54 at the second folding position 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 roller 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 a standby position outside the path to an operating position that is in pressure contact with the peripheral 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 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 in contact with the peripheral surface of the second roller 49 located downstream of the first roller 41 in the sheet moving direction of the first conveyance path 32, and the curved guide 53b is located upstream of the first roller 41. It is arrange | positioned in the position along the surrounding surface.

  The elevating member 53c is supported by a guide rail (not shown) provided on the apparatus frame, and is driven at a predetermined stroke with the driven roller 53a at a standby position above the first transport path and an operating position in contact with the peripheral surface of the second roller 49. Shift means for reciprocating between the two. 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.

  The operating position at which the driven roller 53a is in pressure contact with the second roller 49 is in the vicinity of the tangent line L between the contacts (contact points A and B shown in FIG. 15) in contact with the outer peripheral surfaces of the first roller 41 and the second roller 49. Is set. Further, this operation position is set so that the folding angle of the sheet to be folded is 90 degrees or less (see FIGS. 16 and 19).

  By the operation of the deflecting means 53, as shown in FIG. 16, the sheet is first pushed by the driven roller 53a and moved downward, and then the first roller 41 and the second roller 49 are pressed by the press contact of the driven roller 53a and the second roller 49. It is deflected and conveyed in the direction of the nip point with the two rollers 49.

  By arranging the deflecting means 53 and the first roller 41 and the second roller 49, which are folding rollers, as described above, an accurate folding operation can be performed for the following reason.

  As a first point, since the upper and lower positions of the rollers 41 and 49 are different from each other with respect to the conveyance path, as shown in FIG. 17, even if the sheet S to be conveyed is largely curled downward and bent, The jamming by being caught by the two rollers 49 is prevented. In this case, the range R in which the second roller 49 advances downstream in the sheet S conveyance direction from the first roller 41 is a portion where the second roller 49 is located below the first roller 41. The sheet S is prevented from being caught.

  As a second point, as shown in FIG. 18, the sheet S is pressed downward by the lowering of the driven roller 53a, and the sheet is bent to be nipped between the driven roller 53a and the second roller 49. The lower back of the sheet can be smoothly conveyed to the nip position of the first roller 41 and the second roller 49 without slippage even with a weak pressure contact force.

  In order to weaken the sheet, as shown in FIG. 19, when the driven roller 53a further contacts, the angle d formed between the upstream and downstream of the sheet is set to 90 degrees or less with the driven roller 53a as a middle point. Can bend the sheet. Therefore, when the driven roller 53a is in pressure contact with the peripheral surface of the second roller 49, the sheet guide 61 in the first guide posture position supports the downstream sheet to 90 degrees or less with respect to the upstream sheet. It may be a structure like that.

  Further, since the sheet is along the peripheral surface of the first roller 41 and the peripheral surface of the driven roller, the sheet is reliably conveyed, the variation in the folding position can be prevented, and the sheet can be folded at an accurate crease position.

  The third point is that the pressure contact between the driven roller 53a and the second roller 49 is positioned in the vicinity of the tangent line between the contacts contacting the outer peripheral surfaces of the first roller 41 and the second roller 49. The contact position with the two rollers 49 can be brought close to the nip position between the first roller 41 and the second roller 49. Thereby, since the loop can be formed at a distance close to the nip, the fold position can be accurately conveyed to the nip position of the first roller 41 and the second roller 49.

  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 54c 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 standby 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 standby 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 standby position to the operating position, and the elevating member 53c of the primary folding deflector 53 is moved from the operating position to the standby position in this rotational direction. 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 standby position by forward and reverse rotation of the shift motor MS.

[Sheet transport mechanism]
The sheet transport mechanism of the first transport path 32 and the second transport path 33 will be described with reference to FIGS. In the first conveyance path 32, a pair of carry-in rollers 40a and 40b are arranged at the sheet carry-in entrance 30, and carry a sheet sent from the outside of the apparatus. A pair of paper feed conveyance rollers is disposed between the intersection K of the first conveyance path 32 and the second conveyance path 33 and the carry-in roller pairs 40a and 40b. The illustrated pair of paper feed / conveying rollers includes a first roller 41 and a pinch roller 42 pressed against the first roller 41.

  In the first transport path 32, a resist area Ar is provided on the downstream side of the pair of carry-in rollers 40a and 40b, 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 41, a second roller 49, and a third roller 50 are disposed in pressure contact with each other in the second conveyance 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 conveyance path 32 described above, and the edge (leading edge and trailing edge) of the sheet carried into the first switchback path 34. Is detected. 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 sheet carry-in port 30 to the first folding position Np1.

"Assumed Configuration"
A first folding position (nip position) Np1 of the first roller 41 and the second roller 49 and a primary folding deflecting means 53 are disposed at the intersection K. Further, a pair of paper feed rollers 41 and 42 are arranged on the first conveyance path 32 on the upstream side of the intersection K, and the first switchback path 34 located on the downstream side of the intersection K conveys the sheet. No means are arranged. For this reason, a plurality of transport mechanisms do not interfere with each other to cause uneven transport speed. The primary folding deflecting means 53 includes a driven roller 53a that is in pressure contact with the circumferential surface of the second roller 49 located on the downstream side in the traveling direction of the sheet moving along the first conveying path 32. The driven roller is a standby position outside the path. To and from the operating position pressed against 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 Vh for moving the driven roller 53a of the primary folding deflector 53 from the standby position to the operating position is set to be higher than the sheet conveying speed Vs for moving the first conveying path 32 (for example, Vh = 1. 7 × Vs speed setting). For this reason, the peripheral speed Vs of the pair of paper feed rollers 41 and 42 and the lowering speed Vh of the elevating member 53c are set to Vh> Vs. This speed control controls the rotation speed of the transport motor MF of the first roller 41 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 Vh from the top dead center (solid line in FIG. 5) to a point P3 where the driven roller 53a contacts the sheet fed through the first conveying path 32, and the driven roller 53a is second. A case will be described in which the roller 49 decelerates and stops after a predetermined time after contacting the roller 49. FIG. 6B shows a case where the elevating member 53c is stopped at the timing when the driven roller 53a contacts the second roller 49.

  The nip pressure between the pinch roller 42 and the first roller 41 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 roller 49 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 sheet that is fed out by the pair of sheet feeding and conveying rollers 41 and 42 and nip conveyed only to the pair of sheet feeding and conveying rollers descends the driven roller 53a at the intersecting portion K in the direction perpendicular to the conveying direction. The speed Vh is set higher than the sheet conveying speed Vs. For this reason, the movement displacement amount of the sheet front end portion in the first switchback path 34 is larger than the movement displacement amount of the sheet rear end portion fed out by the pair of paper feed conveyance rollers 41 and 42. 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 folding position Np1 with reference to the pressure contact P1 of the pair of sheet feeding and conveying rollers 41 and 42 at the rear end.

  At the same time, the friction load (conveyance load) of the 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 folding position Np1 by the driven roller 53a without shaking.

  Further, the first switchback path 34 is formed in a curved path shape. As a result, the posture of the leading end of the sheet sent out by the pair of paper feed / conveying rollers 41 and 42 in this path does not fluctuate, and a curved path is formed when the driven roller 53a is fed to the first folding position Np1. The friction load (conveyance load) of the guide member that acts is greatly affected as compared with the linear path.

  Further, in FIG. 5, the pressure contact of the pair of paper feeding and conveying rollers 41 and 42 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 a sheet that moves on the first conveying path 32. When the first contact point is P3, the sheet conveyance length Dy between P1 and P2 (the broken line length in FIG. 5) is longer than the sheet conveyance length between P1 and P3 (Dx: see FIG. 5). Dy> Dx Set to.

  As a result, when the sheet fed by the pair of paper feeding and conveying rollers 41 and 42 is guided to the first folding position Np1 by the driven roller 53a, Dy> Dx is set and Vh> Vs is set at the same time. The rear end portion is not pulled from the pressure contact P1 of the pair of paper feeding and conveying rollers 41 and 42. Accordingly, the sheet is guided to the first folding position Np1 with reference to the pressure contact P1 at the rear end.

Further, the speed is set so that the following equation is established when the stroke of the driven roller 53a from the contact P3 to the pressure contact P2 is Dz.
(Dy−Dx) / Vs≈Dz / Vh
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 42 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.

  A sheet is carried into the first switchback path 34 by a pair of carry-in rollers 40a and 40b and a registration roller (first roller) 41 arranged in the first conveyance path 32 in the second conveyance path 33, and the first and second Two rollers 41 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 conveying paths 32 and 33 is simplified to reduce the size of the apparatus, reduce the noise, and reduce the power consumption. For this reason, a part of the outer periphery of the folding roller (first roller 41) arranged in the second conveyance path 33 is partly placed in the first conveyance path 32 between the carry-in roller pair 40a, 40b and the carry-out roller pair 62a, 62b. It arrange | positions so that the conveyance path | route 32 may be faced.

  A pinch roller 42 is disposed on the outer periphery of the first roller 41, and the sheets sent from the pair of carry-in rollers 40 a and 40 b are sent to the first switchback path 34. Thereby, it is not necessary to arrange a special transport roller in the second transport path 33, and the transport mechanism is simplified.

  In the present invention, a pair of folding rolls 41 and 49 are arranged in conveyance paths 32 and 33 having a sheet carry-in port 30 and a sheet carry-out port 31. A pair of carry-in rollers 40a and 40b is arranged at the carry-in entrance 30 of the first and second conveyance paths 32 and 33, and the sheet is guided to the first folding position Np1 by the pair of rollers. A sheet leading edge detecting means (first sensor) S1 for detecting the leading edge of the sheet fed by the pair of carry-in rollers is disposed in the transport path. In addition, a sheet deflecting unit 53 that guides the sheet fold to the nip position of the pair of folding rolls is disposed in the second conveyance path 33. The sheet deflecting means 53 is composed of a roller (driven roller), a blade, and the like for inserting the sheet fed into the path from the standby position outside the path to the nip position.

  In such a configuration, the present invention carries the sheet into the apparatus at a speed that matches the sheet conveying speed Vs sent from the upstream side image forming apparatus A with the carry-in roller pair 40a and 40b. As a result, the sheet is sent to the folding processing means 48 at the same speed as the image forming speed. In this case, the speed of the sheet sent from the image forming apparatus A is sent at a very wide speed according to the image forming conditions.

  Therefore, the present invention is based on the sheet conveyance speed Vs sent from the upstream image forming apparatus A and the timing (detection signal from the leading edge detection means) when the leading edge of the sheet reaches a predetermined position (first sensor S1 position). In addition, a sheet deflection speed Vh for moving the primary folding deflection means 53 from the standby position to the operating position and a calculation means 98 for calculating the movement start timing of the primary folding deflection means 53 are provided. Then, the sheet deflection speed Vh by the primary folding deflector 53 is set to be higher than the sheet conveyance speed Vs with a constant magnification relationship.

  In the present invention, the primary folding deflection means 53 is constituted by a driven roller that comes into contact with the circumferential surface of the folding roll pair, which will be described later, or the sheet fold position from the standby position outside the path to the nip portion of the folding roll pair. It is composed of a folding blade (folded plate) for inserting the.

  The present invention includes the following calculation means 98. First, the sheet deflection speed Vh by the primary folding deflecting means 53 is set at a higher speed than the sheet conveyance speed Vs by the carry-in roller pair 40a, 40b at a constant magnification. In the illustrated example, Vh = 1.7 Vs is set. As shown in FIG. 5, the speed ratio is a direction in which the sheet conveying direction (horizontal direction in the figure) and the sheet deflection speed (vertical direction in the figure) are substantially orthogonal to each other. Or Vh is set from experimental values so that Vh is slightly larger (faster) than Vs.

  As a result, the sheet moves at the speed of the pair of carry-in rollers 40a and 40b, and the speed acting on the sheet satisfies the sheet deflection speed Vh> the sheet conveyance speed Vs. It is possible to contact the second roll 49 without shifting the contact point. The conveyance speed of the pinch roller 42 and the first roller 41, which will be described later, is set to a speed that matches the speed (Vs) of the carry-in roller.

Therefore, the time when the primary folding deflecting means 53 starts moving from the standby position from the timing when the sheet leading edge detecting means (first sensor) S1 detects the sheet leading edge (detection signal of the first sensor S1) (detection signal of the first sensor S1). (Delay time from) Tx is calculated by the following equation.
Vh = 1.7 Vs Formula 1
Tx = Tb−Ta Expression 2
In this case, “Ta” is the time from when the deflecting member 53 starts moving from the standby position to when it first contacts the sheet, and is the sum of the acceleration time and the constant speed time of the shift motor MS. Here, the constant speed time of the shift motor MS is obtained by (Da-acceleration distance) / Vh. “Da” is the moving distance of the deflecting member 53, and “acceleration distance” is a cumulative acceleration distance calculated from the motor control table and the amount of stepping per pulse (for example, the number of power supply pulses) ) × (stepping amount per pulse)).

“Tb” is obtained by the following equation.
Tb = Db / Vs
Db = Dc + (Dd−De)
“Dc” is the distance between the sensor detection position P4 and the position P3 where the deflection member 53 first contacts the sheet. “Dd” is the distance from the first folding position Np1 to the sheet leading edge P5. “De” is a distance between the first folding position Np1 and the contact point P2 in contact with the peripheral surface of the second roller 49.

[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 conveyance path 33 is halved by the first and second rollers 41 and 49, or ½ position of the sheet size leaving a binding margin at the end of the sheet. Fold together (primary fold).

  In the case of three-fold folding, the sheet sent to the second conveyance path 33 is left by the first second rollers 41 and 49, leaving a binding margin at one-third position of the sheet size or at the sheet edge. Fold position (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 transport path 36.

  In the case of three-fold folding, as shown in FIG. 12A, when the inner three-fold is performed, the sheet fed to the second transport path 33 is fed by the first second rollers 41 and 49 to the sheet rear end side 1 / The three positions are folded, and then the sheet leading end side 1/3 position is folded. Similarly, at the time of 1 / 3Z folding, the sheet fed to the second conveyance path 33 is folded at the sheet leading end side 1/3 position by the first second rollers 41 and 49, and then the sheet trailing end side 1/3 position is set. Fold together.

  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 conveying path 33 is fed by the first second rollers 41 and 49 to the sheet rear end side 1. / 4 position is 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 conveying path 33, or sensor means (S1, S2 shown in the figure) for detecting the position of the sheet leading edge. ). 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 99 stores data for calculating the sheet crease by the crease position calculating 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).

  Further, the control CPU 95 is provided with a calculation means (sheet deflection timing calculation means) 98 for calculating the operation timing of the primary folding deflection means 53 described above. This calculation means is based on a detection signal obtained by detecting the leading edge of the sheet by the first sensor S1. A delay time (the aforementioned Tx) for starting the primary folding deflection means 53 is calculated. The calculation method is as described above.

[Folding operation]
The operation of the configuration of the sheet folding apparatus B will be described. FIG. 7A shows a state in which the sheet entering the sheet carry-in entrance 30 is corrected for registration, and FIG. 7B shows a state in which 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 where the folded sheet is carried in, FIG. 9B shows a state where the driven roller 54a is in pressure contact, FIG. 10A shows a state where the sheet is folded at the second folding position Np2, and FIG. The state of unloading is shown respectively.

  In FIG. 7A, the sheet is guided to the sheet carry-in entrance 30 and is sent to the downstream side by the carry-in roller pair 40a and 40b. 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 transport path 32 to the first switchback path 34 as shown.

  Then, the sheet is carried into the first switchback path 34 by the pair of sheet feeding and conveying rollers 41 and 42. A first sensor S1 is disposed in the first conveying path 32 on the downstream side of the pinch roller 42 and the first roller 41, 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 higher than the sheet conveying speed sent from the first conveying path 32, the sheet conveyed by the driven roller 53a is guided to the nip portion (first folding position) Np1 of the pair of folding rollers. When doing so, the sheet does not bend. 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 transport path 32 is deformed into a V shape toward the first folding position 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 folding position Np1 by the conveying force of the pinch roller 42 and the first roller 41. At this time, the curved guide surface of the curved guide 53b regulates the sheet along the peripheral surface of the roller along the peripheral surface of the first roller 41.

  Accordingly, the sheet is fed to the first folding position Np1 by the driven roller 53a at the leading end side, and the rear end side is fed toward the first folding position Np1 by the pinch roller 42 and the first roller 41, and the lifting timing of the lifting member 53c. Will determine the crease position. Therefore, the control means 95 determines the speed at which the sheet is transferred by the pinch roller 42 and the first roller 41 and the timing at which the driven roller 53a is moved 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 circumferential surface of the opposing first roller 41 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, the sheet folded at the first folding position Np1 at the 1/2 position (folded twice), 1/3 position (trifolded), and 1/4 position (trifolded) is the first folded position. The conveyance force is applied at the position 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 folding position Np2 and sent to the sheet 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 folding position 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 side of the sheet is driven roller 54a, and the trailing edge side is the first folding position Np1, and the sheet is fed in the opposite direction to be guided to the second folding position 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 in pressure contact with the second roller 49, and transferred to the third transport path 36. . Therefore, the control means 95 sends the folded sheet to the paper discharge path 37 or returns it to the first transport 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 case of a three-fold mode such as a two-fold or a 1 / 4Z-fold that requires post-processing such as filing or bookbinding processing, the sheet is transferred from the third transport path 36 to the first transport path 32, and from the sheet exit 31. Send to post-processing device 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. Therefore, the sheet deflection timing calculation unit 98 calculates the operation timing of the primary folding deflection unit 53 (St05).

  The control means 95 moves the primary folding deflection means 53 from the standby position to the operating position after the delay time (Tx) calculated by the sheet deflection timing calculation means 98 has elapsed (St06, St07). 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 on the first conveying path 32 is directed toward the first folding position Np1 with reference to the fold position as described with reference to FIG. 8B. It is distorted. When the driven roller 53a of the primary folding deflector 53 comes into contact with the peripheral surface of the second roller 49, the sheet is dragged and inserted from the fold position to the first folding position Np1.

  At this time, in the bi-fold mode, the control means 95 moves the secondary folding deflecting means 54 after the expected time (St08) when the sheet fold is inserted into the first folding position Np1 with reference to the detection signal from the first sensor S1. It moves to the operating position (St09). This estimated time is set to a time before the fold position of the sheet is inserted into the first fold position Np1 and the leading end of the folded sheet reaches the bending 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 positioned 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 folding position Np2, the driven roller 54a As the third roller 50 rotates, it is reliably guided to the second folding position Np2.

  Therefore, the control means 95 carries out the folded sheet carried out from the second folding position Np <b> 2 to the third conveyance path 36 to the first conveyance path 32. Then, the control means 95 prepares for the subsequent sheet processing with the secondary folding deflecting means 54 positioned at the operating position (St10). The illustrated one has a relationship in which 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 discharge 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. 7 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 (St11), the first sensor S1 detects the leading edge of the sheet (St12).

  Therefore, the control means 95 calculates the operation timing of the primary folding deflection means 53 by the sheet deflection timing calculation means 98 (St13).

  After the delay time (Tx) calculated by the sheet deflection timing calculation means 98 has elapsed, the primary folding deflection means 53 is moved from the standby position to the operating position (St14, St15). 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 on the first transport path 32 is directed toward the first folding device Np1 with reference to the fold position as described with reference to FIG. 8B. It is distorted. When the driven roller 53a of the primary folding deflector 53 comes into contact with the peripheral surface of the second roller 49, the sheet is dragged and inserted from the fold position to the first folding position Np1. 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 (St16).

  Based on the signal that the second sensor S2 detects 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 (St17). (St18). This estimated time is set by the calculated value of the crease position calculating means 97. Accordingly, the sheet is inserted with the conveying force from the driven roller 54a into the second folding position Np2. The front end of the sheet is detected by the paper discharge sensor S3, and is carried out from the third transport path 36 to the first transport path 32 or is transported from the paper discharge path 37 to the storage stacker 65 according to the folding specification (St17).

[Output path configuration]
The folded sheet folded in half as described above is fed to the second conveying 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 transport path 36. The third transport path 36 joins the first transport path 32 as described above. A paper discharge path 37 is branched from the third transport path 36 and is continuously provided via a path switching flapper 66, and the paper discharge path 37 is folded into a storage stacker 65 disposed below the second transport path 33. To guide you. The paper discharge path 37 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.

  Accordingly, a sheet folded in letter specifications such as inner three-fold or 1 / 3Z-fold that does not need to be transferred to the post-processing apparatus C is stored in the storage stacker 65 without being transferred to the sheet carry-out port 31.

  Of the folded sheets sent to the third conveying path 36, the sheet to be transferred to the post-processing apparatus C and to be post-processed is transferred toward the sheet carry-out port 31 by the pair of carry-out rollers 62a and 62b. 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 sheet 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.

30 Sheet carry-in port 31 Sheet carry-out port 32 First conveyance path (conveyance path)
33 Second transport path 41 First folding roller (first roller)
49 First folding roller (second roller)
53a Follower roller 53c Shift means (elevating member)
54b Curved guide 61 Sheet guide means B Sheet folding device Np1 Nip position (first folding position)

Claims (7)

Sheet folding processing means arranged in the sheet conveyance path,
A folding roller pair comprising a first folding roller disposed at a position for conveying the sheet in the conveyance path, and a second folding roller rotating in the opposite direction in contact with the outer peripheral surface of the first folding roller. ,
A driven roller in contact with the outer peripheral surface of the second folding roller at an operating position in the vicinity of the nip position of the sheet when the outer peripheral surface of the pair of folding rollers is in contact with a crease in the sheet;
Shift means for reciprocally moving the driven roller between a standby position above the transport path and the operating position;
The second folding roller is arranged downstream and below the first folding roller in the transport path,
The sheet folding apparatus, wherein the operating position is set at a position further away from the distance from the conveyance path of the rotation shaft of the first folding roller.   2. The sheet folding according to claim 1, further comprising a curved guide for guiding a sheet to be folded along the outer peripheral surface of the first folding roller to a nip position of the sheet. apparatus.   3. The sheet folding apparatus according to claim 1, wherein the operating position of the driven roller is set in the vicinity of a tangent line between contact points that contact each outer peripheral surface of the folding roller pair on the operating position side. .   The sheet folding apparatus according to claim 3, wherein the operating position of the driven roller is set so that a folding angle of the sheet when folding is performed at the operating position is 90 degrees or less. .   5. The sheet folding apparatus according to claim 4, further comprising sheet guide means for supporting the folding angle of the sheet at 90 degrees or less.   5. The shift unit according to claim 1, wherein a speed at which the driven roller is moved from the standby position to the operating position is set to be higher than a sheet speed at which the conveying path is moved. Sheet folding device. The transport path is
A first conveyance path for carrying out the sheet carried in from the sheet carry-in port to the sheet carry-out side without folding the sheet,
A second transport path arranged to intersect the first transport path and folding the sheet from the sheet carry-in entrance,
The second transport path is
A path end portion that guides the sheet to the fold roller pair nip portion and a path end portion that guides the folded sheet to the downstream side are arranged in areas facing each other through the first conveyance path,
The sheet guide is provided at an intersection between the first conveyance path and the second conveyance path,
The sheet guide is configured to guide the sheet from a sheet guide entrance position toward the sheet unloading position, and a first guide posture position for guiding the sheet from a path end portion of the second conveying path to the nip position side. The sheet folding apparatus according to claim 1, wherein the sheet folding apparatus is configured to be movable between two guide posture positions.

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