JP7202883B2 - Sheet folding device, sheet processing device and image forming device - Google Patents

Description

The present invention relates to a sheet folding device that performs folding processing on a sheet, and a sheet processing device and an image forming apparatus that include a sheet folding mechanism that performs folding processing on a sheet.

2. Description of the Related Art Conventionally, a sheet folding device is widely known that performs folding processing at a predetermined position on a sheet on which an image is formed by an image forming device such as a copier or printer. The folding process includes folding the sheet in half at the center position, folding the sheet into three by folding the sheet inward at two points, and folding the sheet in three by alternately folding the sheet inward and outward, so-called Z-folding.

A sheet folding device is provided with a pair of feed rollers on the upstream side of a horizontal upper guide plate, a pair of sheet folding rollers on the downstream side, and a sheet guide deflection member (that is, a thrusting member) on the upstream side of the sheet folding roller pair. known (see, for example, Patent Literature 1). In this device, the paper piece guiding/deflecting member moves from a second position in which the paper piece guiding/deflecting member is retracted obliquely downward on the upstream side of the paper folding roller pair to a first position in which the leading edge is brought close to the paper piece inlet of the paper folding roller pair. A predetermined position of the piece of paper hanging in the space in front of the folding roller is drawn into the paper piece drawing-in port, and the piece of paper is folded in half or Z-fold.

A sheet conveying roller is provided on the upstream side of the sheet conveying path in which the lower guide plate and the upper guide plate face each other, and a sheet bending roller is provided on the downstream side of the sheet conveying path. A sheet processing apparatus has been proposed that includes a pressing member (that is, a thrusting member) that is movable between a second position that is retracted obliquely downward on the upstream side, and similarly performs folding in half and Z-folding on a sheet material. (See Patent Document 2, for example). From the second position, the pressing member presses the sheet hanging down from the notch opened between the sheet conveying roller and the sheet bending roller against the upper guide plate with the roller at the tip thereof, and moves the sheet on the upper guide plate. It moves along the plate to a first position, guides the folding position of the sheet material to the nip of the sheet folding roller, and folds it by its rotation.

JP-A-2002-68583 JP-A-2005-67741

In the conventional device described in Patent Document 1, the paper piece guiding/deflecting member pushes the paper piece with its leading end (small roller) and moves to a first position close to the paper piece intake port. There is a large gap above and below the Therefore, the paper slip tends to sag downward on the upstream side from the tip of the paper slip guiding and deflecting member. As a result, there is a possibility that the position of the paper piece against which the paper piece guide/deflection member abuts may deviate from a predetermined portion in the sheet conveying direction while the paper piece is moving toward the paper piece lead-in opening.

In addition, the amount of slackness and curvature of the paper on the upstream side of the leading edge of the paper piece guide/deflect member is not only due to the difference in sheet characteristics such as stiffness, but also due to the difference in the paper piece guide/deflect member during its movement toward the paper piece lead-in opening. It varies depending on the state and may change. A piece of paper is wound into the pair of paper folding rollers from the position where it first contacts the roller surfaces. Variation may occur depending on the degree of curvature.

The displacement of the abutting position of the paper piece guide/deflection member against the paper piece and the variation of the contact position of the paper piece on the roller surface directly result in the variation of the position of the crease formed on the paper piece by the pair of paper folding rollers. As a result, the folding positions of the folded pieces of paper are uneven, and the dimensions in the sheet conveying direction vary, resulting in a poor appearance.

As described above, in the conventional device described in Patent Document 2, in a state in which the pressing roller at the tip of the pressing member presses the sheet material against the upper guide plate, the folding position of the sheet material is adjusted to the nip of the sheet folding roller. By moving to the first position leading to the upper end of the pressing member, the sheet material is prevented from being slackened on the upstream side of the leading end of the pressing member. However, as in the case of Patent Document 1, the pressing member moves obliquely from the retracted position (second position) located obliquely downward on the upstream side from the first position. A vertical gap is created between the plates. As a result, the sheet material having weak stiffness tends to loosen in the gap between the upper guide plate and the same problem as in Patent Document 1 may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional problems described above. To improve the appearance of folded sheets by reducing or eliminating variations in folding positions formed on sheets and irregularities in folded sheets caused thereby.

The sheet folding device of the present invention includes a feed roller for transporting a sheet in a predetermined transport direction, a pair of folding rollers arranged downstream of the feed roller along the transport direction, and a sheet transported by the feed roller. a thrusting member capable of thrusting the sheet and moving to a thrusting position for nipping a predetermined position of the sheet with the pair of folding rollers; and a controller for controlling the conveying speed of the sheet by the feed roller so as to decrease from a first speed to a second speed slower than the first speed, and the moving speed of the thrusting member. is decelerated from the first speed to the second speed after the sheet conveying speed by the feed roller is decelerated .

According to another aspect of the present invention, a sheet processing apparatus of the present invention includes the above-described sheet folding apparatus of the present invention.

Further, in another aspect of the present invention, an image forming apparatus of the present invention comprises an image forming unit for forming an image on a sheet, and the above-described sheet folding apparatus of the present invention for folding the sheet sent from the image forming unit. or a sheet processing apparatus.

According to the sheet folding device of the present invention, the control unit changes the sheet conveying speed by the feed roller from the first speed to the second speed, which is slower than the first speed , in a part of the range in which the thrust member moves to the thrust position. After the sheet conveying speed of the feed roller is reduced, the moving speed of the pushing member is reduced from the first speed to the second speed . Therefore, when the thrusting member reaches the thrusting position, the curve of the sheet facing the nip portion of the folding roller pair near the tip of the thrusting member is kept substantially constant, and the predetermined position of the sheet is nipped by the folding roller pair, and the fold is formed. Since it can be formed, variations in folding positions and resulting unevenness of folded sheets can be reduced or eliminated, and the appearance of folded sheets can be improved.

1 is an overall configuration diagram of an image forming system to which the present invention is applied; FIG. 1 is a schematic configuration diagram of a sheet folding device according to the present invention; FIG. (a) is a perspective view showing the entire driving mechanism of the sheet folding device, and (b) is an enlarged view of the essential part thereof. Schematic diagram illustrating a preferred arrangement of the thrusting member in the retracted position. FIG. 2 is a block diagram showing the control configuration of the sheet folding device; (a) is a plan view of the sheet before folding processing, and (b) is an end view of the sheet folded in three (Z-fold) by the sheet folding device. 4 is a flowchart for explaining the overall processing operation of the sheet folding device; 4A to 4F are cross-sectional views showing the folding process of the sheet folding device in the order of steps. 4 is a flowchart for explaining registration processing; 6 is a flowchart for explaining loop formation processing; The flowchart explaining the retraction|saving process of a veneer. 6 is a flow chart for explaining the thrusting process of the thrusting board. 4 is a time chart showing speed control of a pair of registration rollers, a pair of folding rollers, and a veneer; FIG. 4 is an enlarged cross-sectional view of a main part showing a sliced veneer that moves along the second route of the central conveying path; 6 is a flowchart for explaining a crease forming process; FIG. 4 is an enlarged cross-sectional view of a main part showing a sliced veneer that moves along the second lower guide portion; 4 is a flowchart for explaining the movement of the veneer to the guide position;

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[Image forming system]
FIG. 1 shows the overall configuration of an image forming system to which the present invention is applied. The image forming system shown in the figure comprises an image forming apparatus A, a sheet post-processing apparatus B, and a sheet folding apparatus C connected therebetween. A sheet on which an image has been formed by the image forming apparatus A is conveyed through the sheet folding apparatus C, and is received by the sheet post-processing apparatus B in a discharge tray. The image forming apparatus A, sheet post-processing apparatus B, and sheet folding apparatus C will be described below.

[Image forming apparatus]
The image forming apparatus A is of a type that forms an image on a sheet by a known electrostatic printing mechanism. not shown). An image reading section 5 consisting of a scanner unit and an automatic document feeding section 6 thereon are integrally provided on the upper portion of the device housing 1 . The image forming apparatus A of the present embodiment is of a so-called internal paper discharge type, and has a U-shaped front face defined largely between the image forming section 3, the paper discharge section 4, and the image reading section 5 in FIG. A transport relay unit 7 is arranged in the paper space. In addition to the electrostatic printing mechanism described above, the image forming apparatus A can employ various other image forming mechanisms such as an inkjet image forming method, an offset printing method, and a silk printing method.

A plurality of sheet feeding cassettes 2 a and 2 b having different sheet sizes are detachably provided in the apparatus housing 1 in the sheet feeding section 2 . The sheet feeding unit 2 containing the sheet for image formation feeds out the sheet of the size instructed by the control unit from the corresponding sheet feeding cassette to the sheet feeding path 8 . A registration roller 9 is provided in the paper feed path 8, and the sheets whose leading edges are aligned by the registration roller are fed to the downstream image forming section 3 at a predetermined timing.

The image forming section 3 has an electrostatic drum 10 and a print head, a developing device, a transfer charger, etc. arranged therearound. The print head is composed of, for example, a laser emitter and forms an electrostatic latent image on the electrostatic drum 10 . The developer adheres toner ink to the electrostatic latent image to form a toner image, which is transferred to a sheet by the transfer charger. The sheet onto which the toner image has been transferred is conveyed to a fixing device 11 where it is heated and pressurized to fix the toner image.

The paper ejection path 12 branches downstream into a first paper ejection path 13 on the upper side in FIG. 1 and a second paper ejection path 14 on the lower side. The first paper ejection path 13 and the second paper ejection path 14 are connected to an upper first paper ejection port 15 and a lower second paper ejection port 16 that open into the paper ejection space, respectively.

The sheet discharge section 4 can be provided with a sheet circulation path (not shown). The sheet circulation path connects the paper ejection path 12 to the paper feed path 8 on the downstream side of the fixing device 11 on the upstream side of the registration rollers 9, for example. The image-formed sheet sent out from the image forming section 3 to the sheet discharging path 12 is switched back to the sheet circulation path by reversing the sheet discharging roller of the sheet discharging path 12, and the surface thereof is turned upside down, and the sheet is sent to the image forming section again. 3, images can be formed on both sides of the sheet.

As shown in FIG. 1, the transport relay unit 7 has a substantially L-shape when viewed from the front. and a second relay portion 18 extending to the left side of the device housing 1 . The upper surface of the second relay portion 18 forms a substantially flat sheet ejection tray 19 within the sheet ejection space.

A first relay path 20 is provided inside the first relay section 17 , and a first sheet inlet 21 thereof is connected to a first sheet discharge port 15 of the sheet discharge section 4 . It is arranged above the sheet ejection tray 19 so as to open to the sheet ejection space. The first relay path 20 is provided near the first sheet outlet 22 with a carry-out roller driven by a motor built in the first relay section 17 . The image-formed sheet conveyed from the paper discharge section 4 through the first paper discharge path 13 passes through the first relay path 20 and is conveyed to the sheet discharge tray 19 in the paper discharge space by the discharge roller. be.

A second relay path 23 is provided inside the second relay section 18 , and a second sheet entrance 24 thereof is arranged so as to be connected to the second paper discharge port 16 of the paper discharge section 4 . A second sheet outlet 25 of the second relay path 23 opens substantially on the same plane as the left side surface of the apparatus housing 1, and is connected to a sheet inlet of the sheet folding apparatus C as described later. The second relay path 23 is provided with a plurality of conveying rollers that are driven by a motor built in the second relay section 18 to convey the sheet. The image-formed sheet conveyed from the paper discharge section 4 through the second paper discharge path 14 passes through the second relay path 23 and is sent to the sheet folding device C by the conveying rollers.

The image reading section 5 includes a platen 26 on which a document sheet is placed, a reading carriage 27 that moves along the platen, and an optical reading means 28 such as a CCD device. The document paper on the platen 26 is scanned and optically read by the reading carriage 27 , and the optical image generated thereby is photoelectrically converted into image data by the optical reading means 28 . The automatic document feeder 6 automatically feeds the document sheets set in the paper feed tray 29 to the platen 26 .

With the above-described configuration, the image forming apparatus A reads a document sent from the document feeding section 5 by the image reading section 4, and forms an image on the sheet sent from the paper feeding section 3 by the image forming section 2 according to the read image data. do. A sheet on which an image has been formed is conveyed from the sheet discharging section 4 through the first sheet discharging path 13 and then through the first relay path 20 when the folding processing by the sheet folding device C and the post-processing by the sheet post-processing device B are not performed. It passes through and is carried out to the sheet ejection tray 19 in the sheet ejection space. When performing the folding process and/or the post-processing on the sheet on which the image has been formed, the sheet is conveyed from the sheet discharging section 4 through the second sheet discharging path 14, passes through the second relay path 23, and is sent to the sheet folding device. sent to C.

[Sheet post-processing device]
As shown in FIG. 1, the sheet post-processing apparatus B has a first conveying path 101 for conveying a sheet from the sheet folding device, and second and third conveying paths branched from the first conveying path. 102, 103, a post-processing device such as the stapling unit ST1, and a binding processing tray 104. FIG. On one side (the left side in FIG. 1) of the housing 100, first and second discharge trays 105 and 106 for stacking and storing sheets discharged from the sheet post-processing apparatus B are vertically spaced apart. there is The sheet post-processing device B is arranged so that the sheet inlet 107 of the first conveying path 101 is connected to the sheet outlet of the sheet folding device C, which will be described later.

The first paper discharge tray 105 is arranged below the paper discharge port 108 of the second transport path 102 that opens on the side surface of the housing 100 . Sheets sent from the sheet folding device C are conveyed from the first conveying path 101 to the second conveying path 102 when the sheet post-processing device B does not perform stapling processing by the stapling unit ST1 and/or other post-processing. , is discharged from the discharge port 108 to the first discharge tray 105 as it is.

A discharge port 109 of the third conveying path 103 is arranged above the binding tray 104 so as to face the sheet mounting surface of the binding tray 104 . A sheet sent from the sheet folding device C is conveyed from the first conveying path 101 to the third conveying path 103 in the case of performing the stapling process by the stapling unit ST1, and is loaded onto the stapling processing tray 104 from the discharge port 109 thereof. discharged on the surface. A plurality of sheets stacked on the binding processing tray 104 are stapled into a sheet bundle by the stapling unit ST1, conveyed from the binding processing tray, and discharged from the downstream end to the second paper discharge tray 106 below. be.

[Overall Configuration of Sheet Folding Device]
In the sheet folding device C, as shown in FIG. 2, a transport path 32 is formed inside a housing 31 from a sheet carry-in port 32a on the image forming apparatus A side to a sheet discharge port 32b on the sheet post-processing device B side. there is Along the sheet conveying direction, the conveying path 32 is provided with a pair of registration rollers 33 on the upstream side, a pair of folding rollers 34 on the downstream side, and a thrust plate 35 between the pair of rollers. The sheet folding device C has the sheet carry-in port 32a at the second sheet outlet 25 of the transport relay unit 7 installed in the image forming apparatus A, and the sheet discharge port at the sheet carry-in port 107 of the sheet post-processing device B, as described above. 32b are arranged to connect to each other.

Further, an additional folding mechanism 36 can optionally be provided in the vicinity of the sheet discharge port 32b of the transport path 32. FIG. In a folding mechanism such as the sheet folding device C, in order to reliably fold the conveyed sheet at the folding line position, providing an additional folding mechanism that presses the sheet at the folding line position downstream after the folding process is provided. They are conventionally well known to those skilled in the art.

[Registration roller pair]
The registration roller pair 33 consists of an upper driving roller 33a and a lower driven roller 33b, which are arranged across the transport path 32 in the figure. The driven roller 33b has its roller surface pressed against the roller surface of the driving roller 33a by, for example, a suitable spring means (not shown), so that the driven roller 33b follows the driving roller 33a as it is rotated by a registration motor, which will be described later. to rotate.

The sheet sent out from the transport relay unit 7 of the image forming apparatus A by the discharge roller pair 37 near the second sheet exit 25 has its leading edge pressed against the roller surface of the registration roller pair 33 that stops rotating. By abutting against the nip portion 38, the tip positions are aligned. The sheet whose skew has been corrected by aligning the leading edge position is conveyed along the conveying path 32 toward the pair of folding rollers 34 by driving the pair of registration rollers 33 at a predetermined timing.

In another embodiment, the registration roller pair 33 can be replaced by a discharge roller (corresponding to the discharge roller pair 37 in FIG. 2) that discharges the sheet from the image forming apparatus A to the sheet folding device C. As a result, the number of parts of the sheet folding device C can be reduced, the manufacturing cost can be reduced, and the size of the entire device can be reduced in the sheet conveying direction. In this case, the discharge roller pair 37 preferably has a function of aligning the leading edge positions of the sheets carried into the transport path 32 as described above.

[Folding roller pair]
The folding roller pair 34 is composed of an upper upper folding roller 34a and a lower lower folding roller 34b, which are arranged across the transport path 32 in the drawing. Both rollers 34a and 34b are pressed against each other by, for example, suitable spring means (not shown) in order to nip and fold the leading edge and crease of the sheet sent from the registration roller pair 33 as will be described later. At the same time, in such a pressed state, they are synchronously rotated in the sheet conveying direction by a common folding roller drive motor, which will be described later.

The folding roller pair 34 is arranged so that the nip portion 38 of the registration roller pair 33 is positioned above a tangent line 39a passing through the nip portion 39, which is the pressure contact portion of the roller surfaces. In the embodiment of FIG. 2, the tangent line 39a and the tangent line 38a passing through the nip portion 38 of the registration roller pair 33 are both oriented generally horizontally, and the tangent line 38a is oriented with a certain vertical offset such that the tangent line 38a passes above the tangent line 39a. It is

[Conveyance route]
As shown in FIG. 2, the transport path 32 includes a sheet transport path 41 extending along the sheet transport direction from a sheet inlet 32a to a registration roller pair 33, and a central transport path 42 extending from the registration roller pair to the folding roller pair 34. and a sheet delivery path 43 extending from the pair of folding rollers to the sheet delivery port 32b.

The sheet carry-in path 41 includes an upper carry-in guide 41a and a lower carry-in guide 41b arranged vertically opposite each other along the sheet conveying direction so as to guide the leading edge of the sheet to be carried in to the nip portion 38 of the registration roller pair 33. have. As described above, the upper carry-in guide 41a is arranged so that when the leading edge of the sheet is brought into contact with the nip portion 38 of the registration roller pair 33 to align the leading edge positions, the sheet fed from the upstream side to the discharge roller pair 37 is positioned along the sheet carry-in path. In order to secure a loop-shaped bendable space within 41, the area near the registration roller pair 33 is greatly expanded upward toward the entrance side.

As shown in FIG. 2, the central conveying path 42 is arranged vertically in opposition along the sheet conveying direction so as to guide the sheet whose leading edge is aligned by the pair of registration rollers 33 to the nip portion 39 of the pair of folding rollers 34 . It has a transport guide 45 and a lower transport guide 46 . The sheet is conveyed through the central conveying path 42 while being restricted from both sides in the thickness direction by the upper and lower conveying guides 45 and 46 (in this embodiment, from above and below).

As described above, the tangent line 38a that passes through the nip portion 38 of the registration roller pair 33 and the tangent line 39a that passes through the nip portion 39 of the folding roller pair 34 are arranged horizontally with a vertical height difference. , a first horizontal portion 45a horizontally extending downstream along the tangent line 38a, a second horizontal portion 45b horizontally extending upstream along the tangent line 39a, and a horizontal line extending from the upstream side to the downstream side so as to connect the tangent lines 38a and 39a. and a sloped portion 45c that slopes downward to the side.

As shown in FIG. 2, the inclined portion 45c is formed in a straight line from the upstream end of the second horizontal portion 45b to the upper right side in the figure. The inclined portion 45c and the second horizontal portion 45b intersect linearly, and at the connecting portion thereof, there is a convex portion 47 which is formed by a relatively large obtuse-angled corner portion and projects generally downward in the central conveying path 42. formed. Similarly, the connecting portion between the inclined portion 45c and the first horizontal portion 45a is also formed at a relatively large obtuse angle.

In another embodiment, the connecting portion between the inclined portion 45c and the second horizontal portion 45b can be curved. In this case, the protruding portion 47 is formed by a curved portion that protrudes generally downward in the central conveying path 42 . A connecting portion between the inclined portion 45c and the first horizontal portion 45a can be similarly curved. In another embodiment, the convex portion 47 can be formed by a member separate from the second horizontal portion 45b and the inclined portion 45c of the upper conveying guide 45. FIG.

In this embodiment, as shown in the figure, the first horizontal portion 45a, the inclined portion 45c, and the upstream portion of the second horizontal portion 45b are formed by one continuous first upper conveying guide member, and the second A downstream portion of the horizontal portion 45b is formed by another second upper conveying guide member. The first and second upper conveying guide members are arranged substantially continuously so as not to interfere with sheet conveying in the central conveying path 42 . Further, the first upper transport guide member can be formed by a plurality of substantially continuous guide members, and the boundary between the first upper transport guide member and the second upper transport guide member is also positioned as shown in FIG. It can be set in various other ways.

The lower conveying guide 46 includes a first lower guide portion 46a extending from the registration roller pair 33 to a predetermined position downstream in the sheet conveying direction, and a first lower guide portion 46a extending from the folding roller pair 34 to a predetermined position upstream along the sheet conveying direction. and a second lower guide portion 46b extending to. The first and second lower guide portions 46a and 46b are spaced apart and fixed to the housing 31 so as to define a large gap 48 therebetween along the sheet conveying direction. A gap 48 between the first and second lower guide portions 46a and 46b is selectively opened and closed by a veneer 35 horizontally movable toward a nip portion 39 of the pair of folding rollers 34, as will be described later.

A relatively large loop forming space 50 is provided below the gap 48 of the lower conveying guide 46, as shown in FIG. When the veneer 35 is retracted (indicated by solid lines in FIG. 2) to open the gap 48 , the sheet in the central conveying path 42 can hang down from the gap 48 into the loop forming space 50 . When the veneer 35 advances (indicated by an imaginary line 35' in FIG. 2) and the gap 48 is closed, the sheet fed from the registration roller pair 33 does not hang down in the loop forming space 50 and is can be conveyed toward the pair of folding rollers 34 along the .

The first lower guide portion 46a includes a first horizontal guide portion 51a extending horizontally downstream from the registration roller pair 33 generally facing the first horizontal portion 45a of the upper transport guide 45, and further downstream from there, It has a first inclined guide portion 51b that is inclined substantially parallel to the inclined portion 45c of the upper conveying guide halfway. The downstream end of the first inclined guide portion 51b defines the position where the sheet begins to hang down when the gap 48 is opened. In this embodiment, as illustrated, the downstream end of the first inclined guide portion 51b is positioned above a tangent line 39a passing through the nip portion 39 of the folding roller pair 34. As shown in FIG.

The second lower guide portion 46b includes a second horizontal guide portion 52a horizontally extending upstream from the folding roller pair 34, a second inclined guide portion 52b inclined downward upstream from the second horizontal guide portion, and the second horizontal guide portion 52b. and a vertical guide portion 52c extending generally vertically downward from the second angled guide portion. The second horizontal guide portion 52a cooperates with the second horizontal portion 45b of the upper conveying guide 45 to regulate the sheet from both sides in the thickness direction, i.e., the vertical direction, while folding the leading edge of the sheet to the nip portion of the pair of rollers 34. Guide to 39. The second inclined guide portion 52 b is inclined toward the loop forming space 50 so as to guide the sheet hanging down in the loop forming space 50 to the nip portion 39 of the folding roller pair 34 . The vertical guide portion 52c secures the dimension of the loop forming space 50 and, together with the second inclined guide portion 52b, separates the sheet hanging in the loop forming space 50 from the folding roller pair 34 side.

When the veneer 35 is at the retracted position, the sheet fed from the pair of registration rollers 33 to the central conveying path 42 passes the downstream end of the first inclined guide portion 51b and passes through the gap 48 opened downward from the tip of the sheet. It hangs down linearly in the loop forming space 50 . On the other hand, when the gap 48 is opened with the leading edge of the sheet nipped by the folding roller pair 34 and the folding roller pair stopping rotation, the sheet in the central conveying path 42 is moved into the gap 48 as will be described later. It bends and hangs down in loop form space 50 through.

In other words, the central conveying path 42 consists of a first path portion for sending out the sheet from the pair of registration rollers 33, a second path portion capable of selectively opening the central conveying path 42 to the loop forming space 50 below, and a second path portion for folding the sheet. and a third path portion for guiding to the nip portion 39 of the roller pair 34 . The upper surface side of the sheet of the first to third path portions is substantially continuous in the sheet conveying direction by an upper conveying guide 45 composed of the first and second upper conveying guide members. On the lower surface side of the seat, the first path portion is formed by a fixed first lower guide portion 46a, and the third path portion is formed by a fixed second lower guide portion 46b. , the second path portion is composed of a gap 48 that is opened and closed by the movement of the veneer 35 .

In another embodiment, the first path portion can be formed by only a horizontal guide portion without the first inclined guide portion 51b. In FIG. 2, the position where the upper conveying guide 45 transitions from the inclined portion 45c to the second horizontal portion 45b is set within the range of the gap 48 of the second path portion, but it is not limited to this. As long as the second lower guide portion 46b also guides the sheet hanging in the loop forming space 50 to the nip portion 39 of the folding roller pair 34, the second inclined guide portion 52b can be made smaller than shown in FIG. 2 or eliminated. and the vertical guide portion 52c can be reduced or eliminated as long as sufficient loop forming space 50 is secured.

The sheet carry-out path 43 has an upper carry-out guide 43a and a lower carry-out guide 43b that are vertically opposed to each other along the sheet carrying direction so as to guide the folded sheet to the sheet carry-out exit 32b. In front of the sheet outlet 32b, for example, an additional folding mechanism having a plurality of rolling elements that move on the lower outlet guide 43b in the sheet width direction perpendicular to the sheet conveying direction to additionally fold the creases of the folded sheet. 36 is provided.

[Veneer board]
The veneer 35 is formed of a flat plate member extending in the sheet width direction of the central conveying path 42, as shown in FIGS. The veneer 35 is horizontally arranged at substantially the same height as the nip portion 39 of the folding roller pair 34 . Further, the thrust plate 35 is horizontally movable between a retracted position below the first lower guide portion 46a indicated by solid lines in FIG. 2 and a guide position and thrust position indicated by imaginary lines 35' and 35''. ing.

When the veneer 35 is at the retracted position, as shown in the figure, the gap 48 of the lower conveying guide 46 is completely opened, and the central conveying path 42 is opened to the loop forming space 50 below at the second path portion. be. Therefore, the sheet in the central conveying path 42 can hang down from the central conveying path 42 into the loop forming space 50 as will be described later.

At the guide position indicated by the imaginary line 35', the veneer 35 completely closes the gap 48 of the lower conveying guide 46 and forms a part of the lower conveying guide 46 by facing the upper conveying guide 45 vertically. As a result, the sheet in the central conveying path 42 is guided through the second path portion without hanging down in the loop forming space 50, and is conveyed from the first path portion to the third path portion.

At the thrust position of the imaginary line 35'', the thrust plate 35 enters between the second horizontal portion 45b of the upper conveying guide 45 and the second horizontal guide portion 52a of the second lower guide portion 46b at the third path portion. This thrusting position is a position where the tip of the thrusting plate 35 folds the sheet and feeds it into the nip portion 39 of the pair of rollers 34 .

FIG. 4 specifically shows an enlarged example of a preferred arrangement of the veneer 35 at the retracted position. As shown in the figure, there is a height H between the second horizontal portion 45b of the upper conveying guide 45 and the second horizontal guide portion 52a of the second lower guiding portion 46b of the lower conveying guide 46 facing thereto. is defined. Thus, the third path portion of the central transport path 42 has a linear portion 66 extending horizontally and linearly upstream from the pair of folding rollers 34 .

The height H of the straight portion 66 is between the second horizontal portion 45b of the upper conveying guide 45 and the second horizontal guide portion 52a of the lower conveying guide 46 on both upper and lower sides of the veneer 35 positioned within the straight portion. It is set so that several sheets can pass through smoothly while being piled up. In this embodiment, the width is set to 2 mm, for example, in consideration of the thickness of two sheets that can be used in the image forming apparatus A so that the sheet folded in two can pass through. As a result, the thrusting plate 35 can smoothly move to the thrusting position in the third path section while thrusting the sheet with its leading edge in the folding process described later.

It is preferable that the tip of the thrusting plate 35 is arranged in the gap of the straight portion 66 of the third path portion so as to be close to the nip portion 39 of the folding roller pair 34 at the thrusting position. Therefore, the veneer 35 of FIG. 4 is arranged horizontally within the range of the height H of the extension line 66a extending upstream from the straight portion 66 at the retracted position. From this retracted position, the tip of the veneer 35 moves horizontally and linearly toward the nip portion 39 of the folding roller pair 34 .

More specifically, in FIG. 4, the veneer 35 of this embodiment is positioned above or slightly below a tangent line 39a extending upstream from the nip portion 39. As shown in FIG. As a result, the tip of the thrust plate 35 can be brought closer to the nip portion 39 at the thrust position, which is convenient.

The retracted position of the veneer 35 is not limited to the range of the height H of the extension line 66 a of the straight portion 66 . If the sliced plate 35 moving toward the folding roller pair 34 moves horizontally along the upper conveying guide 45 in the third path portion and the leading end can be brought close to the nip portion 39 at the thrusting position, The retracted position can be provided at a position different from 4.

3(a) and 3(b) show the configuration of the veneer 35 in more detail. As shown in the figure, in this embodiment, four pairs of folding rollers 34 each comprising upper and lower folding rollers 34a and 34b are attached to upper and lower roller shafts 55 and 56, respectively. The four pairs are arranged symmetrically, two pairs on each side of the center position along the axial direction of the roller shafts 55 and 56 . At the tip of the veneer 35, four notches 57 having shapes and dimensions corresponding to the shapes of the four pairs of folding rollers 34 are formed along the sheet width direction corresponding to the positions of the four pairs of folding rollers 34. recessed.

Movement of the sliced plate 35 between the retracted position, the guide position and the thrusting position is performed by driving a sliced plate drive motor MT3 of the drive mechanism shown in FIG. 5, which will be described later. The driving of the veneer driving motor MT3 is controlled by the control unit 120 shown in FIG. 5 as described later.

[Driving Mechanism of Sheet Folding Device]
3A and 3B show drive mechanisms 58 to 60 for the registration roller pair 33, the folding roller pair 34, and the cutting plate 35 of the sheet folding device C. FIG. The registration roller pair 33 is attached so that the drive roller 33a rotates integrally with a roller shaft 61 that is rotatably installed in the sheet width direction. In the pair of folding rollers 34, the upper and lower folding rollers 34a and 34b are attached to roller shafts 55 and 56, which are also rotatably installed in the sheet width direction, so as to rotate together.

The drive mechanism 58 for the registration roller pair 33 includes a registration roller drive motor MT1, a drive pulley P1 attached to its rotating shaft, a driven pulley P2 attached to one end of the roller shaft 61 of the drive roller 33a, and both pulleys P1. , and P2. The driving force of the registration roller driving motor MT1 is transmitted from its rotating shaft to the driving roller 33a through a transmission mechanism including a driving pulley P1, a timing belt TB1 and a driven pulley P2.

The drive mechanism 59 for the folding roller 11 includes a folding roller driving motor MT2, a driving pulley P3 attached to its rotating shaft, a driven pulley P4 attached to the roller shaft 56 of the lower folding roller 34b, and both pulleys P3 and P4. and a timing belt TB2 that is stretched between them. Further, the driving mechanism 59 includes a gear Z1 coaxially and integrally rotatably attached to the roller shaft 56, and a gear Z2 which is coaxially and integrally rotatably attached to the roller shaft 55 of the upper folding roller 34a and meshes with the gear 1. and

The driving force of the folding roller driving motor MT2 is transmitted from its rotating shaft to the lower folding roller 34b via a transmission mechanism consisting of a driving pulley P3, a timing belt TB2, and a driven pulley P4. Further, the driving force of the folding roller drive motor MT2 is transmitted from the roller shaft 56 to which the driven pulley P4 is attached to the upper folding roller 34a via gears Z1 and Z2 that mesh with each other. As a result, the upper folding roller 34a and the lower folding roller 34b rotate synchronously in directions opposite to each other, and the sheet nipped between the folding rollers can be conveyed in the sheet conveying direction in cooperation.

A drive mechanism 60 for the sliced plate 35 includes a sliced plate drive motor MT3, a driving pulley P5 attached to its rotating shaft, a rotating shaft 62 extending in the sheet width direction, and a driven pulley P6 attached to one end thereof. , a timing belt TB3 entrained between both pulleys P5 and P6; and a second rack and pinion mechanism 64 provided in.

The first rack-and-pinion mechanism 63 has a first pinion 63a that is coaxially and integrally rotatable on the one end side of the rotating shaft 62 and is attached to the inside of the driven pulley P6, and is attached to one end of the veneer 35. , and a first rack 63b that meshes with the first pinion 63a. The second rack-and-pinion mechanism 64 includes a second pinion 64a that is similarly attached to the other end of the rotating shaft 62 so as to be coaxially rotatable together with the second pinion 64a, and is attached to the other end of the veneer 35 to form a second pinion. and a second rack 64b that meshes with 64a. The first and second racks 63b, 64b are arranged so that the sliced board 35 moves horizontally as the first and second pinions 63a, 64a rotate.

The drive force of the veneer drive motor MT3 is transmitted from its rotary shaft to the first and second pinions 63a, 63b via a transmission mechanism consisting of a drive pulley P5, a timing belt TB3 and a driven pulley P6. As a result, the first and second racks 63b and 64b move synchronously in the same direction and cooperate to move the veneer 35 in the horizontal direction.

[Control Configuration of Sheet Folding Device]
FIG. 5 conceptually shows the control configuration of the sheet folding device C. As shown in FIG. The sheet folding device C has a control section 120 comprising a control board including a CPU. As shown in the figure, the controller 120 is connected to first to third detection sensors S1 to S3 provided along the conveying path 32 .

The first detection sensor S1 is arranged in front of the registration roller pair 33 in the sheet carry-in path 41, and detects the leading edge of the sheet carried in from the image forming apparatus A through the sheet carry-in port 32a. The second detection sensor S<b>2 is arranged in front of the folding roller pair 34 on the central transport path 42 and detects the leading edge of the sheet transported from the registration roller pair 33 to the folding roller pair 34 . The third detection sensor S3 detects the position of the thrust plate 35 moving between the retracted position, the guide position and the thrust position as described above. The detection results of the first to third detection sensors S1 to S3 are output to the controller 120 in real time.

Further, the control section 120 is connected to the control section 121 of the image forming apparatus A via the sheet post-processing apparatus B. FIG. The control unit 121 is connected to an input unit and a display unit (not shown) provided on the setting panel D of the image forming apparatus A. FIG. For example, information such as the sheet type set by the user on the setting panel D and the folding processing mode executed by the sheet folding device C is transmitted from the control unit 121 to the control unit 120 via the sheet post-processing device B. .

In order to acquire and store information transmitted from the control section 121 of the image forming apparatus A, the control section 120 includes a folding processing information acquisition section 124 . The folding information acquisition unit 124 includes a sheet thickness information acquisition unit 125 that acquires and stores information on sheets to be folded, particularly information on the thickness of the sheets, and a size information acquisition unit that acquires and stores information on the size of the sheets. 126 are provided.

If the registration roller drive motor MT1, folding roller drive motor MT2, and sliced plate drive motor MT3 are provided with the additional folding mechanism 36, the control unit 120 is further connected to the additional folding drive motor MT4. Based on the detection results input from the first to third detection sensors S1 to S3 and the various types of information received from the control unit 121 of the image forming apparatus A, the drive motors MT1 to MT3 and optionally MT4 are controlled. , conveying the sheet on the conveying path 32 and the folding processing operation of the sheet folding device C are controlled and executed.

Further, the control unit 120 can transmit information on sheet conveyance, folding processing, and the like performed in the sheet folding apparatus C to the control unit 121 of the image forming apparatus A via the sheet post-processing apparatus B in real time. can. If the information received from the control unit 120 includes information that is undesirable or requires caution or warning, such as defective sheet conveyance or defective folding in the sheet folding device C, the control unit 121 notifies the user of the information. For example, the display section of the setting panel D can be used to notify.

The control unit 120 is provided with a ROM 127 for storing control programs for various controls executed by the control unit 120 as described above and as described later, and data necessary for the control programs. Further, the control unit 120 incorporates a folding loop counter 128, which will be described later.

The sheet folding device C of the present embodiment is suitable for alternately inward-folding and outward-folding a sheet along the sheet conveying direction to fold the sheet in three into a so-called Z-fold. 6A is a plan view of the sheet SH before being folded, and FIG. 6B shows an example of the sheet SH Z-folded by the sheet folding device C from the sheet width direction. In FIG. 6B, the sheet SH is formed with a first fold line 202 at a position of a predetermined length upstream from the leading edge (downstream end) 201 in the sheet conveying direction. A second fold line 203 is formed at the height position.

In FIGS. 6A and 6B, the respective sheets SH are represented so that their tip positions in the sheet conveying direction are aligned. As can be seen from the figure, according to the present embodiment, the sheet SH in FIG. 6B is Z-folded so that the size in the sheet conveying direction is 1/2 of the original sheet size. The folding processing operation of the sheet folding device C will be described below.

[Processing operation of sheet folding device]
The sheet folding device C is preset with a folding processing (Z-folding) mode for performing folding processing of folding (Z-folding) a sheet in three and a non-folding mode for not folding a sheet. The user determines whether or not to fold the image-formed sheet before starting image formation on the sheet in the image forming apparatus A. If folding is to be performed, the folding processing mode is selected in the input section of the setting panel D. Select and enter The input of the folding processing mode is stored in the control unit 121 of the image forming apparatus A as one piece of sheet information of the sheet to be folded.

The overall processing operation in the sheet folding apparatus C will be schematically described with reference to the flow chart of FIG. First, when the first detection sensor S1 detects the leading edge of the sheet carried into the sheet carry-in path 41 and is turned on (Y in step ST01), the control section 120 of the sheet folding device C uses this as a trigger to Sheet information of the detected sheet is acquired from the control section 121 of the image forming apparatus A via the sheet post-processing apparatus B (step ST02). This sheet information includes information on the characteristics of the sheet itself, such as the size, material, thickness (including basis weight) of the sheet, and orientation of the sheet during transport (vertical or horizontal direction), as well as information on folding processing to be performed from now on. information, and information on post-processing such as binding processing performed by the sheet post-processing device B after passing through the sheet folding device C. FIG.

In this embodiment, the information about the basis weight of the sheet to be folded is acquired from the sheet information sent from the control unit 121 of the image forming apparatus A. FIG. In another embodiment, the sheet folding device C itself can acquire the basis weight of the sheet carried in from the image forming device A. FIG. For example, conventionally known is a detection technique in which a sound wave of a predetermined frequency is emitted toward the surface of a sheet and the basis weight of the sheet is calculated from the intensity of the sound wave that has passed through the sheet. By equipping the sheet folding device C with such a detection mechanism, it is possible to immediately handle even a type of sheet that is not intended to be used.

If the sheet information acquired from the control unit 121 of the image forming apparatus A includes the selection of the folding processing mode or the execution instruction of the folding processing (Y in step ST03), the processing advances to steps ST04 to ST06 to execute the folding processing. If the sheet information from the image forming apparatus A does not include the selection of the folding processing mode or the execution instruction of the folding processing, or includes the instruction not to execute the folding processing, the process proceeds to step ST07 to execute the unfolding processing.

In the non-folding process of step ST07, the veneer 35 is placed at the guide position (35'), and the registration roller pair 33 and the folding roller pair 34 are driven to rotate in this state. As a result, the sheet from the image forming apparatus A passes through the conveying path 32 as it is without being folded, and is carried out to the sheet post-processing apparatus B. FIG.

The folding processes in steps ST04 to ST06 generally include registration processing by the registration roller pair 33 (step ST04), folding loop processing by the folding roller pair 34 (step ST05), and crease formation processing by the veneer 35 and the folding roller pair 34. It is performed in three stages (step ST06). In the registration process, the leading edge of the sheet carried into the sheet folding device C is aligned to correct the skew of the sheet. In the folding loop process, a loop for forming a fold line is formed on the leading edge side of the sheet. In the crease forming process, the folding roller pair 34 forms a crease in the looped sheet.

The processing in steps ST04 to ST06 will be specifically described below with reference to FIGS. 8 to 17. FIG. 8A to 8F show the process in which the sheet folding device C carries in the sheet from the image forming apparatus A, conveys it, and folds it in the order of steps.

In the present embodiment, a copy paper that is generally available on the market and is considered to be plain paper and a thicker one are treated as thick paper, and a sheet that is thinner than plain paper is treated as thin paper, and the folding loop counter is used. Perform setting processing. In another embodiment, thick paper can be set to a sheet thicker than plain paper, and thin paper can be set to a sheet having a thickness equal to or less than that of plain paper. Also, the paper size may be divided into three levels of plain paper, thick paper with a greater thickness, and thin paper with a smaller thickness.

Actually, based on the sheet type selected by the user on the setting panel D of the image forming apparatus A, the control unit 120 can be made to recognize the thickness of the sheet. Since the types and thicknesses of sheets scheduled to be used in image forming apparatus A are known in advance, it is only necessary to set in advance whether each type of sheet is thick or thin.

[Resist treatment]
FIG. 8A shows a state in which the leading edges of the sheets are aligned in the registration process of the sheet folding device C. FIG. The registration process is performed, for example, according to the procedure shown in the flowchart of FIG.

When the first detection sensor S1 detects the leading edge of the sheet carried into the sheet carry-in path 41 and is turned on (Y in step ST10), the controller 120 turns on the sensor S1 while the registration roller pair 33 is stopped rotating. Measure the elapsed time from the time point. When this elapsed time passes a preset predetermined time (Y in step ST11), the registration roller driving motor MT1 is driven (step ST12) to rotate the registration roller pair 33. FIG. At this time, the registration roller driving motor MT1 is driven so that the registration roller pair 33 sends out the sheet at a preset first speed va (high speed).

During the predetermined time in step ST11, the leading edge of the sheet abuts against the nip portion 38 of the registration roller pair 33 and bends in a loop shape necessary and sufficient to align the leading edge positions. is the time required to form a sheet at This time can be determined in advance based on, for example, test results and the like, and set in the control unit 120 .

When the registration roller pair 33 is rotated, the sheet is transported along the central transport path 42 to the folding roller pair 34 as shown in FIG. 8B. Triggered by the activation of the registration roller driving motor MT1 in step ST12, the folding loop counter 128 of the control section 120 starts counting (step ST13).

When the sheet SH is delivered from the registration roller pair 33, the veneer 35 is positioned at the guide position 35'. Therefore, the leading edge of the sheet is guided along the central conveying path 42 by the upper surface of the thrust plate 35 and sent straight toward the nip portion 39 of the folding roller pair 34 . The sheet whose leading end has passed through the convex portion 47 of the central conveying path 42 is, in the area where the inclined portion 45c and the second horizontal portion 45b of the upper conveying guide 45 are connected in the sheet conveying direction, that is, in the area facing the gap 48. It is pushed downward by the convex portion 47 and curved convexly toward the loop forming space 50 side.

[Fold loop processing]
The folding loop process is executed, for example, according to the procedure shown in the flowchart of FIG. In step ST13, the control unit 120 drives the registration roller driving motor MT1 and at the same time, drives the folding roller driving motor MT2 to rotate in the forward direction to rotate the folding roller pair 34 forward at the same first speed va as the registration roller pair 33. (step ST20). As shown in FIG. 8B, immediately upstream of the folding roller pair 34, when the second detection sensor S2 detects the leading edge of the conveyed sheet and is turned on (Y in step ST21), the process proceeds to step ST22. move on.

At the same time, the control unit 120 uses multitasking to execute retraction processing for moving the sliced plate 35 from the guide position to the retraction position when the second detection sensor S2 detects the leading edge of the sheet in step ST21. By moving the veneer 35 to the retracted position, the second path portion of the central conveying path 42 is opened to the loop forming space 50 below. The evacuation processing of the veneer 35 will be described later with reference to FIG. 11 .

In step ST22, the control unit 120 sets the driving amount of the registration roller driving motor MT1 to the preset first setting starting from the time when the second detection sensor S2 detects (turns on) the leading edge of the sheet in step ST21. It is determined whether or not the driving amount K1 has been reached. When the first set drive amount K1 is reached (Y in step ST22), the control section 120 stops the folding roller drive motor MT2 (step ST23). Here, the first set drive amount K1 is the drive amount of the registration roller drive motor MT1 required for the leading edge of the sheet to reach the position where it is nipped by the nip portion 39 of the folding roller pair 34 .

As a result, the sheet is held with its leading edge nipped by the nip portion 39 of the folding roller pair 34, as shown in FIG. 8(c). Even after this, the registration roller driving motor MT1 continues to be driven, and the registration roller pair 33 continues to rotate and send out the sheet. As a result, the portion of the sheet on the upstream side of the pair of folding rollers 34 bends and hangs down from the gap 48 into the loop forming space 50 to form a folding loop FL for forming a fold in the sheet. After that, the loop FL also increases according to the amount of sheet feeding by the registration roller pair 33 .

In this embodiment, the feeding amount (conveyance distance) of the sheet from the position where the leading edge of the sheet is detected by the second detection sensor S2 to the position beyond the nip portion 39 of the folding roller pair 34 by 10 mm is measured by the corresponding registration roller. A first set drive amount K1 is set in terms of the drive amount of the drive motor MT1. Here, the driving amount of the registration roller driving motor MT1 includes the amount of rotation of the motor (the number of rotations of the rotating shaft, the rotation angle, the rotation time, etc.) and the amount of feeding of the sheet by the registration roller pair 33, that is, the amount of rotation of the driving roller 33a. (Rotation speed, rotation angle, rotation time, etc. of the roller shaft 61) can be used.

In this embodiment, a pulse motor is used as the registration roller driving motor MT1, and the folding loop counter 128 counts the number of driving pulses of the registration roller driving motor MT1 to detect the sheet feeding amount. Pulse motors are also used for the folding roller driving motor MT2 and the sliced plate driving motor MT3. , the number of driving pulses of the registration roller driving motor MT1.

[Evacuation process]
The retreating process of the veneer 35 can be executed according to the procedure shown in the flow chart of FIG. 11 as described above. The control unit 120 reversely drives the sliced plate driving motor MT3 (step ST50) to move the sliced plate 35 horizontally upstream in the sheet conveying direction from the guide position 35' toward the retracted position. The thrust plate 35 of the present embodiment is provided with a detection flag (not shown) at its upstream end in the sheet conveying direction.

When the third detection sensor S3 arranged below the first lower guide portion 46a detects the detection flag of the sliced plate 35 and turns on (Y in step ST51), it stops the sliced plate driving motor MT3 ( step ST52). As a result, the veneer 35 is placed at the retracted position shown in FIG. 8(c), and the gap 48 between the first and second lower guide portions 46a and 46b is completely opened. As a result, the central conveying path 42 is opened to the loop forming space 50 below at the second path portion, as shown in FIG.

In this embodiment, the folding position of the sheet is preset according to the sheet size and the sheet orientation (vertical direction, horizontal direction) during transport, for example, the folding position represented by the distance from the leading edge of the sheet in the sheet transport direction. It is In the folding loop counter, a predetermined count value is determined in advance for forming a loop on the sheet being conveyed, corresponding to the folding position for each size of the sheet.

After stopping the folding roller driving motor MT2 in step ST23, when the folding loop counter 128, which started counting in step ST13, counts up to the predetermined count value, the next crease forming process (step ST06 ) and the thrusting process of the thrusting board 35 are executed in parallel. The folded loop counter 128 can also be operated to count down, to subtract from the predetermined count value to "0".

[Stab processing]
The thrusting process is executed, for example, according to the procedure shown in the flowchart of FIG. The following description will be made with reference to the timing chart of FIG. FIG. 13 shows changes in the sheet conveying speed of the registration roller pair 33, the sheet conveying speed of the folding roller pair 34, and the moving speed of the thrust plate 35 (positive in the sheet conveying direction) controlled by the control unit 120. FIG. The horizontal axis in the figure is the time axis, and the symbols K2, K4 to K8 shown in the figure represent the number of drive pulses of the drive motors MT1 to MT3 counted in each time interval.

When the folding loop counter 128 counts up to the predetermined count value (step ST70), the control unit 120 drives the veneer driving motor MT3 forward (step ST71) to rotate the veneer 35 at the first speed va. (high speed) to move horizontally toward the folding roller pair 34 side. At this time, the sheet SH continues to be sent to the central conveying path 42 by the registration roller drive motor MT1 being driven. The tip of the thrust plate 35, which has begun to move downstream from the retracted position, hits the folding loop FL at a position near the downstream end of the first lower guide portion 46a of the lower conveying guide 46 where the folding loop FL begins to hang down.

Further, the thrusting plate 35 moves toward the nip portion 39 of the folding roller pair 34 while pushing a predetermined position of the sheet with its tip. FIG. 14 shows in detail how the veneer 35 moves downstream along the second path portion of the central conveying path 42 . As shown in the figure, the veneer 35 moves horizontally and linearly along the tangent line 39a of the nip portion 39 from the retracted position described above with reference to FIG. While the sliced plate 35 passes under the second horizontal portion 45b of the upper conveying guide 45, the upstream portion of the sheet SH from the front end of the sliced plate 35 has a narrow gap between the second horizontal portion and the upper surface of the sliced plate 35. be transported.

The control unit 120 controls the registration roller drive motor MT1 to control the sheet conveying speed of the registration roller pair 33, and at the same time, controls the sliced plate drive motor MT3 to control the moving speed of the sliced plate 35. FIG. In the present embodiment, the moving speed Vb of the thrust plate 35 that starts moving from the retracted position is substantially the same as the sheet conveying speed Vs sent out by the registration roller pair 33, that is, Vb=Vs= It is controlled by v1. While both the velocities Vb and Vs are being controlled in this way, the sheet SH is horizontally moved while the upstream portion of the tip of the sliced plate 35 is supported on the upper surface of the sliced plate 35 substantially in synchronism with the sliced plate 35 . And it moves smoothly to the downstream side in a straight line.

After starting to drive the veneer drive motor MT3, when the drive amount of the registration roller drive motor MT1 reaches the preset fifth set drive amount (K5) (Y in step ST72), the control unit 120 controls the registration The sheet conveying speed of the roller pair 33 is reduced from the first speed v1 to the second speed v2 (low speed). Furthermore, the control unit 120 counts the drive amount of the veneer driving motor MT3 from that point on reaching the fifth set drive amount (K5) in step ST72 as a trigger, and it reaches the seventh set drive amount (K7). When it reaches (Y in step ST73), the sliced plate drive motor MT3 is controlled to reduce the moving speed of the sliced plate 35 from the first speed v1 to the second speed v2 (low speed) (step ST74).

When the moving speed of the sliced plate 35 is reduced to the second speed v2, the driving amount of the sliced plate driving motor MT3 is counted, and when it reaches the fourth set driving amount (K4) (Y in step ST75), the thrusting is started. The driving of the plate driving motor MT3 is stopped (step ST76). As a result, the front end (downstream end in the sheet conveying direction) of the thrust plate 35 is positioned so that the second horizontal portion 45b of the upper conveying guide 45 and the second horizontal guide portion 46b of the second lower guide portion 46b are arranged as shown in FIG. 8E. 52a and stops at the thrust position. Here, the fourth set drive amount (K4) is the drive amount of the sliced plate drive motor MT3 from after the sliced plate 35 is decelerated to the second speed v2 until it is braked so as to stop at the thrust position. be. The amount of rotation of the veneer drive motor MT3 (the number of rotations of the rotary shaft, the angle of rotation, the time of rotation, etc.) of the motor can be used.

As shown in FIG. 16, the sheet pushed by the thrust plate 35 and proceeding downstream along the central conveying path 42 enters the third path section from the second path section, the bottom of which is open to the loop forming space 50. Then, it comes into sliding contact with the second horizontal portion 45b of the upper conveying guide 45 and the second lower guide portion 46b of the lower conveying guide 46 with the sliced plate 35 interposed therebetween, and is restricted from above and below, thereby increasing the resistance. This may cause a sudden increase in the load on the veneer driving motor MT3, causing a loss of synchronism.

Therefore, in this embodiment, the position where the veneer 35 is decelerated to the second speed v2 is set between the second horizontal portion 45b of the upper conveying guide 45 and the second lower guide portion 46b of the lower conveying guide 46. set in front. This suppresses a sudden increase in the load applied to the veneer drive motor MT3, thereby preventing step-out.

[Crease forming process]
First, the operation of the entire crease forming process will be described below in association with the operation of the veneer 35 in the above-described punching process. When the folding loop counter counts up in step ST25 and the thrusting process is started, the registration roller pair 33 continues to feed the sheet, so the loop forming space 50 has a number of sheets as shown in FIG. 8(d). , a desired folded loop FL is formed.

The sheet SH is conveyed toward the pair of folding rollers 34 while being pushed at a predetermined position of the folding loop FL by the tip of the thrust plate 35 that has started to move from the retracted position. A portion of the sheet SH on the upstream side from the front end of the sliced plate 35 enters below the second horizontal portion 45b from the inclined portion 45c of the upper conveying guide 45, and passes the narrow gap between the second horizontal portion and the upper surface of the sliced plate 35. , passes through while being regulated from above. A portion of the sheet SH downstream from the tip of the veneer 35 enters between the loop forming space 50 and the second lower guide portion of the lower conveying guide 46, and is inclined upstream along the second inclined guide portion 52b. confined to form.

As shown in FIG. 8E, when the tip of the veneer 35 enters the straight portion 66 of the third path portion of the central conveying path value 42, the sheet SH moves along the second horizontal portion 45b of the upper conveying guide 45. In the narrow gap between the second lower guide portion 46b and the second horizontal guide portion 52a, the veneer 35 is interposed therebetween and is temporarily folded into a bent form from above and below. This temporarily folded bent position is later pressure-folded by the folding roller pair 34 to form the second fold line 203 of the folded sheet shown in FIG. 6(b).

When the thrusting plate 35 stops at the thrusting position 35″, the folding position FP2 of the sheet SH is bent by the temporary folding described above and is brought to a position immediately before the nip portion 39 of the folding roller pair 34. FIG. As shown in f), the sheet folding position FP2 is caught in the nip portion 39 of the folding roller pair 34 rotated by the folding roller driving motor MT2, and conveyed downstream while being fed to the upper and lower folding rollers 34a and 34b. By this pressure processing, the sheet SH is formed with a second fold line F2 (203) at a predetermined folding position.

In this way, after the sheet SH is forcibly folded in the direction in which it overlaps vertically and is temporarily folded, the sheet SH is nipped by the pair of folding rollers 34 and folded. Stable with high accuracy. Furthermore, the folded portion of the sheet is prevented from being opened at the second folding line F2, so that a folded sheet with a good appearance can be obtained.

Next, each operation of the crease forming process will be described according to the procedure shown in the flow chart of FIG. As described above, the registration roller pair 33 continues to be rotated by the registration roller drive motor MT1 before the movement of the sliced plate 35, and the sheet conveying speed Vs thereof is the same as the moving speed Vb of the sliced plate 35. It is controlled at speed v1. When the drive amount of the registration roller drive motor MT1 reaches the fifth set drive amount (K5) after starting to drive the veneer drive motor MT3 (Y in step ST30), the control unit 120 causes the registration roller pair 33 to convey the sheet. The registration roller drive motor MT1 is controlled so as to reduce the speed to the second speed v2 (step ST31).

As shown in FIG. 13, the deceleration of the registration roller pair 33 to the second speed v2 is achieved by the driving amount of the sliced plate drive motor MT3 for the time corresponding to the seventh set drive amount (K7). It precedes the deceleration to the second speed v2. Until the thrust plate 35 is delayed and decelerated, the sheet SH is placed in a tensioned state between the front end of the thrust plate 35 pushing the sheet SH and the registration roller pair 33 . This delay time of deceleration of the sliced plate 35 is the same as when the slackness caused by the characteristics of the sheet (strength of stiffness) is eliminated in the upstream portion of the sheet SH from the tip of the sliced plate 35 . It is set so that it is in a stretched state.

As a result, after the thrust plate 35 is decelerated, the sheet SH moves horizontally and linearly in a state in which the upstream portion of the tip of the thrust plate 35 is supported on the upper surface of the thrust plate 35 in synchronism with the thrust plate 35. Move smoothly to position. Therefore, while the sheet SH is moved by being pushed by the thrust plate 35, the possibility that the thrusting position of the thrust plate is displaced from the predetermined position of the sheet in the conveying direction is eliminated. Furthermore, when the thrust plate 35 reaches the thrust position, the sheet SH has a substantially constant shape at the portion facing the nip portion 39 of the folding roller pair 34. The position becomes substantially constant, and the variation is eliminated or reduced.

When the driving amount of the registration roller driving motor MT1 reaches the second set driving amount (K2) after the registration roller pair 33 is decelerated to the second speed v2 (Y in step ST32), the control unit 120 performs folding. The driving of the folding roller driving motor MT2 is started so that the roller pair 34 rotates at the second speed v2 (step ST33). As a result, as shown in FIG. 8E, the folding position FP2 pushed by the leading edge of the thrust plate 35 is positioned at the nip portion 39 of the folding roller pair 34 rotating at the same low speed as the registration roller pair 33. Then, the leading end portion of the sheet SH previously nipped is overlapped and folded under pressure to form a second fold line 203 . At this time, the leading edge portion of the sheet SH that has been nipped by the folding roller pair 34 first is sent downstream by the folding roller pair 34 and becomes a tab protruding from the second fold line 203 on the folded sheet.

As shown in FIG. 13, the drive of the folding roller drive motor MT2 is controlled so that the folding roller pair 34 starts rotating before the thrust plate 35 stops at the thrust position. The leading edge of the sheet SH that has been nipped by the pair of folding rollers 34 first moves downstream at the same low speed as the thrust plate 35 . As a result, the protrusion amount (tab amount) of the folded sheet from the second fold line 203 can be minimized and variations can be prevented.

Further, in the present embodiment, the timing of starting the driving of the folding roller drive motor MT2 is set to the third path portion of the central transport path 42, that is, the second horizontal portion 45b of the upper transport guide 45 and the second lower portion of the lower transport guide 46. It is set at a position a predetermined distance from the upstream side between it and the guide portion 46b. The sheet SH forms the folding loop with the leading edge of the sheet nipped by the pair of folding rollers 34 on the downstream side of the tip of the sliced plate, and overlaps vertically at the straight portion 66 of the third path portion. Therefore, when the veneer 35 enters the third path portion of the central conveying path 42 , the lower sheet portion is pushed downstream due to friction with the upper sheet portion, and the leading edge of the sheet is pushed by the folding roller pair 34 . There is a risk that the nipped position will be displaced downstream. In the present embodiment, the position of the thrust plate 35 at which the action of the thrust plate 35 that shifts the position of the leading edge of the sheet begins to occur is experimentally measured in advance, and the folding roller drive motor MT2 is operated based on the result of the measurement. The timing for starting driving is set as described above.

Next, when the driving amount of the folding roller driving motor MT2 reaches the sixth set driving amount (K6) after the driving of the folding roller driving motor MT2 is started (Y in step ST34), the control unit 120 causes the registration roller pair 33 and the folding roller pair 34 to The registration roller driving motor MT1 and the folding roller driving motor MT2 are controlled so as to accelerate the sheet conveying speed to the first speed v1 (high speed) (step ST35). As a result, as shown in FIG. 8F, the folding position FP2 of the sheet SH is caught in the nip portion 39 of the folding roller pair 34 and conveyed downstream while being pressed between the upper and lower folding rollers 34a and 34b. be bent. By this pressure processing, a second fold line F2 (203) is formed on the sheet at a predetermined folding position.

On the other hand, the control unit 120 executes a second retraction process of returning the thrust plate 35 from the thrust position 35″ to the retraction position so as not to prevent the sheet from being caught in the nip portion 39 of the folding roller pair 34 described above. This second saving process will be described later with reference to FIG.

The folding roller pair 34 continues to be rotationally driven even after the cutting board 35 is retracted. Therefore, as shown in FIG. 8(f), the sheet is folded in three (Z-fold) with the leading edge thereof and the second fold line F2 formed by the pair of folding rollers 34 facing first, and then folded by the folding rollers. They are nipped in pairs and transported downstream along the sheet transport path 43 .

As the sheet is conveyed in this way, the fold loop FL in the loop forming space 50 gradually becomes smaller. The folded loop FL enters the third path portion of the central transport path 42 and is squeezed from above and below by the second horizontal portion 45b of the upper transport guide 45 and the second inclined guide portion 52b of the second lower guide portion 46b. , a thin loop shape extending in the sheet conveying direction. Further, the folding loop FL advances between the second horizontal portion 45b and the second horizontal guide portion 52a of the second lower guide portion 46b, and folds from above and below at the folding position FP1 of the trailing end (upstream end) that serves as the first folding line. It is bent in half.

The folding position FP1 of the sheet is conveyed in the bent form in this manner without causing any slippage or displacement in the sheet conveying direction with respect to the upstream portion of the sheet superimposed thereon, and the folding roller pair 34 is pressurized and bent at the nip portion 39 of the . Therefore, the first fold line (202 in FIG. 6B) is stably formed at a desired position on the sheet with a high degree of accuracy without causing variations as in the conventional art.

As a result, as shown in FIG. 6B, a Z-folded sheet SH having a first fold line 202 for inward folding and a second fold line 203 for outward folding is generated. In the present embodiment, as described above, the folding roller pair 34 that is not rotating forms the folding loop FL while nipping the leading edge of the sheet, and then the folding roller pair 34 is rotated to , the leading end portion of the sheet that was nipped when the folding loop FL was formed is Z-folded so as to protrude from the second folding line toward the leading end side (downstream side).

According to the present embodiment, as described above, the folding roller pair 34 is rotated at a low speed to fold the sheet SH under pressure. It can be folded and formed. Further, when the veneer 35 enters the straight portion 66 of the third path portion, the sheet conveying speed of the registration roller pair 33 and the folding roller pair 34 is controlled to be low. Even if the load on the MT2 increases due to the sheet being conveyed downstream in a state of being folded under the veneer 35, it is possible to prevent them from being out of step.

After the registration roller pair 33 and folding roller pair 34 are accelerated to the first speed V1 (step ST35), the trailing edge of the Z-folded sheet on which the first fold line 202 and the second fold line 203 are formed is aligned with the first speed V1. When detected by the detection sensor S1 and the second detection sensor S2 and turned off (Y in step ST36, Y in step ST37), the control unit 120 counts the drive amount of the folding roller drive motor MT2. Then, when the drive amount of the folding roller drive motor MT2 reaches a predetermined drive amount (Y in step ST38), the controller 120 determines that the trailing edge of the sheet SH, that is, the upstream edge in the sheet conveying direction has passed the folding roller pair 34. Then, the registration roller driving motor MT1 and the folding roller driving motor MT2 are stopped (step ST39). As a result, the registration roller pair 33 and the folding roller pair 34 stop rotating.

In step ST36, when the first detection sensor S1 detects the trailing edge of the Z-folded sheet and turns off, the control section 120 executes a guide process of moving the veneer 35 from the retracted position to the guide position 35'. do. At this time, the folding loop FL is set to have already passed the folding roller pair 34 . Therefore, even if the sliced plate 35 is moved to the guide position 35', the conveyance of the sheet in the central conveyance path 42 and the crease formation processing by the folding roller pair 34 are not hindered.

[Second saving process]
Since the second saving process is performed in the same manner as the saving process of FIG. 11, it will be described with reference to FIG. In the state of FIG. 8(e), when a predetermined period of time elapses after the sliced plate 35 stops at the thrusting position 35″, the controller 120 reversely drives the thrusting plate drive motor MT3 to move the thrusting plate 35 to the sheet. The third detection sensor S3 below the first lower guide portion 46a detects the detection flag of the thrust plate 35 and turns on (step ST50). Y) of step ST51, and the thrust board driving motor MT3 is stopped, whereby the thrust board 35 is arranged at the retracted position as shown in FIG.

At this time, the gap 48 between the first and second lower guide portions 46a, 46b is completely opened, and the second path portion of the central conveying path 42 is opened to the loop forming space 50 below. Therefore, the folding loop FL can be smoothly wound into the nip portion 39 of the folding roller pair 34 without being hindered by the veneer 35 continuously from the start of winding in FIG. 8(e).

[Guide processing]
The guide processing is executed, for example, according to the procedure shown in the flowchart of FIG. The sliced plate drive motor MT3 is driven forward (step ST56) to move the sliced plate 35 horizontally toward the folding roller pair 34 side. When the drive amount of the sliced plate drive motor MT3 reaches the preset third set drive amount (Y in step ST57), the sliced plate drive motor MT3 is stopped (step ST58).

Here, the third set driving amount is the driving amount of the thrust board drive motor MT3 required to move the thrust board 35 from the retracted position to the guide position 35'. As a result, the gap 48 between the first and second lower guide portions 46a and 46b is closed by the thrust plate 35, and the trailing edge of the sheet is guided along the center conveying path 42 to the upper surface of the thrust plate 35, and the pair of folding rollers is moved. 34 is conveyed straight. The amount of rotation of the veneer drive motor MT3 (the number of rotations of the rotary shaft, the angle of rotation, the time of rotation, etc.) of the motor can be used.

As described above, the present invention has been described in relation to the preferred embodiments, but the present invention is not limited to the above embodiments, and can be implemented with various changes or modifications within its technical scope. Needless to say.

A: Image forming apparatus B: Sheet post-processing device C: Sheet folding device 31: Housing 32: Conveyance path 33: Registration roller pair 34: Folding roller pair 35: Veneer plate 38, 39: Nip part 41: Sheet introduction path 42: Central conveyance path 43: Sheet discharge path 45: Upper conveyance guide 45a First horizontal portion 45b Second horizontal portion 45c Inclined portion 46 Lower conveyance guide 46a First lower guide portion 46b Second lower guide portion 47 Protruding portion 48 Gap 50 Loop forming space 51a First horizontal guide portion 51b First inclined guide Section 52a Second horizontal guide section 52b Second inclined guide section 52c Vertical guide sections 58 to 60 Drive mechanism 120 Control section 121 Control section 124 of image forming apparatus Folding processing information acquisition section 125 Sheet thickness information acquisition section 126 Size information acquisition section 128 fold loop counter 201 sheet leading edge 202 first fold line 203 second fold line

Claims (6)

a feed roller for conveying the sheet in a predetermined conveying direction;
a pair of folding rollers arranged downstream of the feed rollers along the conveying direction;
a thrusting member capable of thrusting the sheet conveyed by the feed roller to a thrusting position where the sheet is nipped at a predetermined position by the pair of folding rollers;
a control unit that controls sheet conveyance of the feed roller and movement of the thrust member to the thrust position;
The control unit controls the sheet conveying speed by the feed roller to be reduced from a first speed to a second speed slower than the first speed, and controls the moving speed of the thrust member to convey the sheet by the feed roller. A sheet folding device that decelerates from the first speed to the second speed after the speed is decelerated . The folding roller pair nips a predetermined position of the sheet pushed by the pushing member moved to the pushing position , rotates to convey the sheet at the first speed, and folds the sheet at the predetermined position. 2. The sheet folding device of claim 1 , wherein the sheet folding device comprises: a transport path along which the sheet transported by the feed roller is transported from the feed roller to the pair of folding rollers along the transport direction;
a space formed below the transport path so that the sheet hangs down from the transport path on the upstream side of the pair of folding rollers in the transport direction ;
3. The pushing member according to claim 1, wherein the pushing member pushes the predetermined position of the sheet hanging from the conveying path into the space from the upstream side in the conveying direction to move to the pushing position. sheet folding device. The control unit
Decrease the sheet conveying speed by the feed roller from the first speed when the drive of the feed roller reaches a set driving amount from the time when the drive of the feed roller is started;
After the drive amount of the feed roller reaches the drive amount, the movement speed of the thrust member is reduced from the first speed when the movement of the thrust member reaches a predetermined movement amount.
The sheet folding device according to claim 1. a sheet post-processing device;
a sheet folding device according to any one of claims 1 to 4 ;
A sheet processing apparatus comprising: an image forming unit that forms an image on a sheet;
The sheet folding device according to any one of claims 1 to 4 or the sheet processing device according to claim 5 , which folds a sheet sent from the image forming unit ;
An image forming apparatus comprising:

Images