JPH09188448A - Paper sheet branching device and image forming device having the paper sheet branching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity by a method wherein paper sheets conveyed at a high speed are rapidly branched by a branching means for proper paper processing regardless of a conveyance speed after branching. SOLUTION: A paper branching device 300 comprises a first conveyance roller 310 arranged at a paper conveyance passage 307 situated upper stream from a branching means 317; a second conveyance roller 324 to convey paper sheets on the second conveyance passage 309; and first and second power sources 301 and 302 to drive the first and second conveyance rollers. As a result of powers being transmitted from the first and second power sources 301 and 302 to the first conveyance roller 310 through a one-way drive transmission member to effect transmission in a one-way, the power on the high speed rotation side of the first and second power sources 301 and 302 is transmitted to the first conveyance roller 310.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a laser printer equipped with a sheet branching device, and more specifically, a paper path and a sorting means of a sheet conveying section for continuously conveying sheets. The present invention relates to an online device including a sorting and storing device for classification, a sheet branching device applied to a double-sided reversing device of a double-sided image forming device, and an image forming device including the same.

[0002]

2. Description of the Related Art Conventionally, an online apparatus in which a plurality of apparatuses for performing a plurality of jobs of image formed sheets are connected has been used.

For example, the above-mentioned on-line apparatus is a reading / feeding apparatus including a document setting unit for setting a document, an optical system for scanning the document, and a sheet feeding unit for storing a large number of sheets and feeding them. A paper device, an image forming device that forms an image of a fed sheet, a bookbinding device that binds the image-formed sheet, and a sorting storage device that sorts and stores the bound finished product or a single sheet are sequentially connected. Is configured.

On the other hand, there is an image forming apparatus in which a paper feed cassette is provided at the bottom of the main body. In recent years, front-loading is becoming the mainstream in combination with space saving. There is provided an accessory of an image forming apparatus in which an intermediate tray is provided in the lower part of the image forming apparatus, which is connected to a sheet discharge port of an image forming main body, or a sheet re-feeding device is provided to enable image formation on both sides of a sheet.

In addition, the speed of image forming apparatuses has been increasing, and in the case of sheets continuously fed from the sheet feeding section, the distance between sheets, which is the distance between sheets, tends to become shorter. ing. Therefore, in the present situation, the distance between the sheets is secured by increasing / decreasing the conveying speed in the sheet conveying path. However, when the image forming apparatus is in an operating state and paper jams occur inside the apparatus or the power is turned off, a large amount of sheets undergoing image forming processing remain in the apparatus. The user cannot use the image forming apparatus again unless all the sheets are removed, but the sheet removing work inside the image forming apparatus, which is becoming smaller and more dense, becomes a heavy burden. Therefore, there is also an image forming apparatus provided with a recovery function so as to remove only the sheet having the paper jam as much as possible.

On the other hand, in the branch used for bypassing the on-line finishing device, the double-sided reversing device which is a double-sided image forming means, and the intermediate tray, a flapper is generally used as a sheet branching means of the sheet conveying path, and a solenoid is used. The flapper is opened and closed by connecting it. In addition, a nip portion is formed in the sheet conveying path by a conveying roller for conveying the sheet and a pressure roller facing the conveying roller, and the pair of rollers is arranged at an arbitrary position to sandwich the conveyed sheet, The sheet is sequentially conveyed by applying a conveying force to the sheet. Further, the conveying speed of the sheet conveyed on the sheet conveying path is equal to the process speed of the image forming unit, or is increased after passing through the fixing unit from the image forming unit to increase the productivity. There are things I tried to improve. However, in the branching unit and the sheet aligning tray, the distance between the sheets, which is the distance between the sheets, is an important factor for the sheets conveyed at high speed. In other words, it is necessary to operate the flapper between the trailing edge of continuously fed sheets and the leading edge of the sheet that continues behind it, and to perform sequential stacking in the alignment tray, but that operation takes time, To cope with this, the paper interval is widened and the transport speed is slowed down to increase the operating time.

[0007]

However, in the above-mentioned conventional image forming apparatus, as the apparatus becomes multi-functional, the productivity for various modes is required, and the user simply makes a normal one-sided copy. It is becoming more important not only to speed up processing, but also to speed up processing in various modes. However, a finisher connected to the image forming apparatus, such as a folder, a stapler, a bookbinding apparatus, a sorting apparatus,
Alternatively, since the double-sided reversing device or the like is mechanically connected to the image forming apparatus, there is a problem that the sheet conveying path from the sheet feeding unit to the sheet discharging unit becomes long and the conveying time becomes long.

Further, when the paper interval becomes short, the operating time of the mechanical mechanism such as the flapper which is the branching means and the drive switching time becomes longer than the paper moving time. Therefore, it is necessary to set the paper interval to be longer than the operating time of these mechanisms, and it is necessary to control so that the paper conveyance speed is reduced accordingly. The time delay causes a loss of bookbinding time, which leads to a reduction in the productivity of the entire mechanical device.

Therefore, a first object of the present invention is to diverge a sheet conveyed at a high speed by a diverging means so as to perform appropriate sheet processing regardless of the sheet conveying speed after divergence. It is an object of the present invention to provide a sheet branching device that can improve productivity and an image forming apparatus including the sheet branching device.

A second object of the present invention is to quickly branch a sheet conveyed at a high speed, accurately align the sheet in a sheet alignment tray, and perform proper sheet processing. An object of the present invention is to provide an image forming apparatus having high productivity, which can branch sheets according to the image forming speed of the image forming apparatus regardless of the sheet conveying speed of the image forming apparatus in the branching unit.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a first sheet conveying path for carrying in and conveying a conveyed sheet, and the first sheet conveying path. In a sheet branching device including a second transport path for transporting a sheet branched by a branch means from a first transport roller provided in the first sheet transport path on the upstream side of the branch means, and the second transport path. A second transport roller for transporting the sheet on the sheet transport path, a first power source for driving the first transport roller, and a second power source for driving the second transport roller.
And a power source of the first power source in one direction to the first transport roller, and a power source of the second power source in one direction to the first transport roller. A direction drive transmission member, wherein the one-way drive transmission member transmits the power on the high speed rotation side of the first and second power sources to the first transport roller. It is in the seat branching device.

Further, driving means for driving the branching means, detection means for detecting that a sheet has been fed to the first sheet conveying path, and the driving means based on a detection signal from the detection means. Control means for controlling,
It is preferable that the control means controls the first and second power sources at a preset rotation speed.

Further, the sheet branching is provided with a first sheet transporting path for carrying in and transporting the sent-in sheet, and a second transporting path for transporting the sheet branched from the first sheet transporting path by the branching means. In the apparatus, a first power source that drives the first transport roller of the first sheet transport path and a second power source that drives the second transport roller of the second sheet transport path are provided. The first transport roller upstream of the branching unit in the sheet transport direction is connected to the first power source and the second power source, and is configured by a power transmitting unit via a one-way drive transmitting unit. What you did
May be a sheet branching device.

A sheet detecting means is provided in the sheet conveying path upstream of the branching means in the sheet conveying direction, and a control means for controlling the position of the branching means and the driving means of the sheet conveying path is provided. preferable.

Further, the first sheet conveying path downstream from the branching means is a sheet conveying path that passes through the inside of the apparatus, and the second sheet conveying path downstream from the branching means can stack sheets. It may be connected to the tray means.

The present invention can be similarly applied to an image forming apparatus provided with an image forming section and a sheet branching device for branching a sheet on which an image is formed by the image forming section.

Further, the present invention comprises an image forming section, a sheet branching device for branching the sheet image-formed by the image forming section, and a bypass conveying path for conveying the sheet to the image forming section. The same can be applied to the double-sided image forming apparatus.

Further, the sheet on which an image has been once formed is conveyed to the intermediate tray by the conveying path for loading and stacked, and the sheet stacked on the intermediate tray is re-fed by the conveying path for discharging to form an image again. An image forming apparatus having an intermediate tray configured so that the image forming apparatus includes an intermediate tray having a bypass conveying path that directly connects the carry-in carrying path and the carry-out carrying path. A sheet branching device capable of carrying a sheet is provided on the bypass transporting path and the intermediate tray, and the transporting path downstream of the sheet branching device has a speed different from the upstream transporting speed by the sheet branching device. The image forming apparatus is set to.

Further, in the image forming apparatus connected with the finishing device connected online, the finishing device is a sheet branching device provided between the carry-in port and the discharge port,
A conveying path leading from the sheet branching device to a finishing means inside the finishing device, and a conveying speed on the downstream side is set to a different speed with respect to a conveying speed on the upstream side of the sheet branching device; In the image forming apparatus, the bypass speed from the carry-in port to the discharge port via the sheet branching device is equal to or higher than the conveying speed upstream of the sheet branching device. It may be.

Further, the heights of the carry-in port and the discharge port can be set to the same height from the floor surface, and by sequentially connecting to the image forming unit, the discharge port of the final connection finishing device from the image forming unit can be set. Even if multiple sheets are connected to each other, it is a bypass portion that can be conveyed in the sheet conveying path without passing through finishing means inside each finishing device, and when passing through an unselected finishing device, the conveyance speed is set to a high speed. It is also applicable to an image forming apparatus equipped with a sheet branching device that has a control means that can be set so that the sheet is decelerated when the sheet approaches a selected predetermined finishing device and the sheet speed is adjusted to a prescribed speed. obtain.

Further, the branching means for branching the sheet is a flapper that also serves as a sheet transport guide, and includes a rotating support shaft, a transport guide rib extending from the support shaft, and a roller of a rotating body at the tip of the flapper. With flappacoro arranged
A sheet branching device may be characterized in that a transporting roller of the rotating body is arranged at a position facing the flapper roller of the sheet transporting guide member forming the branching portion.

Further, in the above-described sheet branching device, the above-mentioned conveying upper roller and the conveying lower roller which face each other in the sheet conveying path are alternately formed, and the conveying lower roller when the branching means is activated and retracted. Even if the position of the sheet conveying guides of the branching means is the same position, or it is rotatable in the direction of further retracting from the same position, or the flapper roller is in the direction of narrowing the inter-guide gap of the conveying lower roller at the branching position. ,
It is preferable to have a structure capable of guaranteeing a minimum gap that allows the sheet to slip through.

The present invention can be similarly applied to an image forming apparatus provided with an image forming unit and the above-described sheet branching device for branching a sheet on which an image is formed by the image forming unit.

[Operation] Based on the above configuration, the sheet sent to the first sheet carrying path passes through the branching means of the first sheet carrying path by the first carrying roller to the next processing device. Be transported to. Next, when the sheet is branched to the second conveyance path, the detection unit detects that the sheet is fed to the first sheet conveyance path, and based on the detection signal, the control unit causes the branching. By controlling the driving means so as to rotate the means upward, the sheet is branched into the second sheet and is conveyed to the next processing device by the second conveying roller. The second transport roller is a second
It is driven by the power source of. The first transport roller is
It is driven by the first power source via the one-way drive transmission member, and is driven by the second power source via the one-way drive transmission member. Therefore, the first transport roller is driven by the power source of the faster one of the first and second, so that even if the speeds of the first and second transport rollers are different, There is no need to switch the speeds of the first and second power sources.

Further, the driving means of the two systems can be driven while switching to the same driving system with respect to the branching means, the flapper roller is provided at the tip of the branch flapper which is the branching means, and the vicinity of the flapper roller is provided. The upper and lower transport rollers are provided on the upper sheet transport guide, and the transported sheet can be biased by the upper transport roller and the lower transport roller. Without doing so, it is possible to branch a short sheet of paper or a sheet conveyed at a high speed, and switch between jobs, and thus it is possible to provide a sheet branching apparatus with high productivity.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the sheet on which an image is formed is branched by using the branching means according to the first embodiment of the present invention and aligned with the sheet bundle S1, and the sheet bundle is wound by using a winding type binding tape. An example of the overall configuration of an online apparatus that is an image forming apparatus that performs bookbinding in S1 is shown. The online device 1 includes a reading / feeding device 201, an image forming unit 202, and a bookbinding device 20.
3 and the sorting storage device 204 are continuously connected. The reading / feeding device 201 has a document table 2 for setting a document (not shown) and an optical system 3 for reading and scanning the set document on the upper part, and stacks sheets S of different sizes on the lower part. A plurality of sheet feeding decks 6 and 7 and sheet feeding units 9 and 10 for feeding the sheet S are arranged.

The fed sheet S is transferred to the sheet conveying section 11
The sheet is conveyed to the sheet conveying path 12 of the image forming unit 202 on the downstream side. Reference numeral 13 denotes a laser scanner that emits laser light based on the image information read by the optical system 3, and reference numeral 15 denotes an image forming body (photosensitive drum) on which a toner image is formed. The sheet S on which the image is formed by the image forming unit 15 is conveyed by the conveyance belt 16 and the conveyance roller pair 17.
The sheet is conveyed to the sheet conveying path 19 of the bookbinding device 203 on the downstream side.

As shown in FIG. 2, the bookbinding apparatus 203 stores the sheet S that is branched and conveyed from the sheet conveying path 19 through the branching means 36 and aligns the sheet S with the sheet aligning tray 4.
1. A vertically movable carriage 6 including an abutting member 59 for abutting the sheet front end, a tape heating device 56 for heating an aligned sheet bundle and a binding tape, and a handling member 805 for handling a bookbinding finished product.
0, and stackers 71, 72, etc. for storing the finished bookbinding product.

In the sorting and storing device 204 shown in FIG. 1, reference numeral 25 is a sheet S conveyed on the sheet conveying path 19.
Is conveyed to the conveying path 26, 27 is a pair of conveying rollers arranged at a plurality of branch portions of the conveying path 26, and 29 is a sheet discharge tray 30 which discharges the sheet S branched at each branch portion to a corresponding sheet discharge tray 30. A roller pair is shown. The finished bookbinding product discharged from the discharge port 139 of the bookbinding apparatus 203 can be discharged from the discharge port 32 to the outside of the machine via the elevator 25 and the conveyance roller pair 31. In addition,
When the sorting and storing device 204 is not connected, the bookbinding device 203 includes a stacking tray (not shown) for stacking the sheets discharged to the first discharge port 19b and the second discharge port 1b.
39, and a stacking tray (not shown) for stacking the finished bookbinding products discharged to 39.

Next, the configuration of the sheet branching device 300 of the online device 1 will be described with reference to FIGS. 3, 4 and 5.

FIG. 3 is a detailed cross-sectional view of the sheet carry-in section of the bookbinding apparatus. The sheet conveying upper guide 307 is the first sheet conveying path and the sheet conveying lower guide 3 is the second sheet conveying path.
When the sheet is loaded in the 09, the upper rollers 308
Then, the lower entrance roller 310 feeds the material to a part of the nip portion. The entrance lower roller 310 is
It is rotated by a driving means described later, and the entrance upper roller 308 is pressed by a spring force so as to be nipped via the nip portion. This roller pair 308, 31
By 0, the sheet reaches the flapper 317 which is a branching unit.

The flapper 317 is rotatable about a flapper shaft 317a, and one end of the flapper 317 is rotatable arm 32.
Via the plunger solenoid 32, which is a driving means.
1 and a return spring 322 which is an elastic member such as a coil spring. Plunger solenoid 3
When 21 is energized, the plunger solenoid is attracted to the right in FIG. At this time, the rotating arm 323 connected thereto is pulled to rotate. Then, the flapper 317 is interlocked and positioned in the state shown in FIG. 4 to guide the sheet in the direction of arrow C. The guided sheet sequentially passes through the pair of transport rollers 324 and 325 and is sent to a unit located downstream.

When the downstream processing device is not used by the sheet branching device 300, the flapper 317 is in a closed state as shown in FIG. At this time, the plunger solenoid 321 is in a non-energized state, and the rotating arm 323 is pulled by the return spring 322 to maintain the position of the flapper 317 shown in the figure. With this configuration, the sheet S fed from the first carry-in port 19a enters from the arrow A, obtains a conveying force by the nip between the upper entrance roller 308 and the lower entrance roller 310, and guides the upper surface of the flapper 317 by sliding to guide the arrow. It is conveyed in the direction of B. This route is used as a so-called bypass transport route. That is,
In the online device 1, the connected device is in a sleep state in some cases, and when there is no command from the controller CPU of the image forming unit 202, the state is as shown in FIG. The transport speed of the bypass unit can be set to a high speed so that the transport unit 204 can be quickly transported to the next sorting storage device 204.

Next, along with FIG. 5, a schematic cross-sectional view of the driving means is shown and with reference to FIG. 3, the structure of the driving means will be described.

In FIG. 3, the sheet carried in from the arrow A is conveyed toward the arrow B. At this time, the sheet is conveyed at a high speed because it is used as a bypass in the online device. Therefore, the transport rollers 308, 310, 330 arranged in this transport path rotate at high speed. On the other hand, when the flapper 317 is actuated as shown in FIG. 4 so that the sheet is conveyed by the arrow C, it may be conveyed at high speed or may be conveyed at low speed depending on the processing apparatus installed downstream. For example, in the case of the bookbinding device 203, the alignment tray 42 (see FIG. 6) is provided downstream of the arrow C, but in this case, the sweeping means is a sweeping means for sequentially stacking sheets in the alignment tray. Aligning member 50
Must be operated reliably, the distance between the sheets is increased by increasing the sheet conveying speed in the direction of arrow C in order to increase the distance between the sheets. In this case, the upper entrance roller 308 and the lower entrance roller 310 must rotate at a constant speed in conjunction with the sheet conveying rollers 324 and 325.

In FIG. 5, the first motor 301 is used as a drive source and is transmitted from the timing pulley 331 through the belt 303 to the timing pulley 327 equipped with the one-way bearing 327a to drive the entrance lower roller 310. On the other hand, similarly using the second motor 302 as a drive source, the drive is transmitted to the transport roller 325, the drive is transmitted to the transport roller 324 via the timing belt 329, and the one-way bearing 327a is mounted via the timing pulley 328 and the timing belt 304. The drive is transmitted to the entrance lower roller 310 by the timing pulley 327. At this time, two driving forces are applied to the entrance lower roller 310, but the one-way bearing 3
27a is provided, so that the motor rotates substantially following any motor rotating at a high speed. This is because the control of the conveyance speed can be set individually by the motors 301 and 302 according to the branching means,
When both motors 301 and 302 are rotating, when one of the jobs ends, the motor 30 on the end job side
If you stop 1 (302), the rotation speed will be reduced automatically.
The other motor 302 (301) follows the rotation speed to rotate. By this, it is conveyed continuously,
It is possible to smoothly branch without the need to control the space between the sheets of paper entering from the entrance.

Next, the detailed structure of the bookbinding apparatus 203 for binding the sheets branched by the sheet branching apparatus 300 will be described with reference to FIG.

The bookbinding apparatus 203 has a sheet conveying path 19 for the sheet S conveyed from the image forming section 202,
A first carry-in port 19a and a discharge port 19b are formed at both ends. A pair of carry-in rollers 20, a plurality of pairs of carry rollers 21, a pair of discharge rollers 22 and the like are arranged from the upstream side along the sheet carrying path 19. A flapper 317 is disposed in the vicinity of the downstream side of the carry-in roller pair 20, and guides the sheet conveying path 19 through the guide portions 309 and 31.
It branches into 6. When the flapper 317 operates to guide the sheet S to the guide portions 309 and 316 or does not operate, the sheet S is directly conveyed in the conveyance path 19.

Downstream of the guide portions 309 and 316,
The sheet aligning tray 41 having the upper guide plate 43 is disposed so as to be inclined so that the downstream side becomes lower, and the abutting member 59 with which the sheet S abuts is disposed on the leading end side thereof. The sheet S carried into the sheet aligning tray 41 by the pair of transport rollers 324 has a sweeping member 49 composed of a belt whose one end is rotatable around the upper left portion in the drawing as a swing center, and an abutting member 59. It is pushed to the side and thrusts into alignment. Further, the alignment in the sheet width direction is carried out by the sweeping member 50 by moving it toward a reference side (not shown). A fan 46 disposed above the upper guide plate 43
Is an object that presses the sheet S carried into the alignment tray 41 with air to prevent the folded sheet from bulging. Reference numeral 53 denotes a clamp member that holds a specified number of sheet bundles. Reference numeral 42 denotes an auxiliary guide plate for the sheet bundle, and 55 denotes a stop finger (operates when one sheet bundle is stored and temporarily stores the first few sheets of the next sheet bundle). I have.

Further, the carriage 60 for transferring the booklet-completed sheet bundle Sl has the following components. That is, the carriage 60 is a housing 801 that is supported by a rotatable chain or the like so as to be vertically movable.
A conveyor belt 803 provided on the housing 801 so as to rotate in the forward and reverse directions; a backing member 802 that moves together with the conveyor belt 803; and an auxiliary guide plate 42.
The rear end of the sheet bundle supported by supporting the sheet bundle by abutting the rear end of the sheet bundle conveyed by and being rotatable around the support shaft 806 from the position of the end portion of the sheet bundle to the retractable position. It has a plate 804, a sheet bundle support rod 805 supported by a link 807 that bends and extends between a position for receiving the bound sheet bundle and a position for passing it to the conveyor belt 803. The sheet bundle support rod 805 is the support shaft 8
It is rotatable around 06.

The sheet bundle rear end support plate 804 moves to a position for supporting the sheet bundle end portion after the clamp member 53 separates the sheet bundle Sl from the tape heating apparatus 56.
When the clamp member 53 is separated from the sheet bundle Sl, the sheet ends are abutted against each other to support the sheet bundle Sl. 77A is the first tape reel, 77B
Indicates a second tape reel, respectively, and the take-up bind tape fed from any one of the tape reels 77A and 77B is cut into a predetermined length by a cutter 618. In FIG. 2, reference numeral 65 denotes a fan that cools the finished bookbinding product, and air flows in the direction of arrow 66. 71,
Reference numeral 72 is a stacker for storing the finished bookbinding product conveyed by the carriage 60, and 70 is a guide rail for guiding the stackers 71, 72 so that they can be pulled out. The configuration and operation of the device 618 (see FIG. 2) for supplying the take-up bind tape for binding from the tape reels 77A and 77B are as described above.

FIGS. 6 to 9 show the sheet alignment tray 41.
3 illustrates a state in which the sheet S is loaded into the sheet and the aligned sheet bundle Sl is transferred to the back surface contact position H. In FIG. 6, one sheet bundle S for bookbinding is placed on the sheet aligning tray 41.
When l is carried in and aligned, the clamp member 53 is moved to the arrow G
And the sheet bundle Sl is clamped. When binding a plurality of copies, the stop fingers 55 are simultaneously activated at this time, and the next bundle of sheets is stacked until the alignment is completed and the sheet bundle Sl clamped by the clamp member 53 is carried out from the alignment tray 41. The sheet S of the number of sheets starts to be temporarily stored from the beginning.

FIG. 7 shows a state in which the abutting member 59 retracts to the standby position and the clamp member 53 moves the sheet bundle Sl from the alignment tray 41 to the back contact position H of the tape heating device 56. There is. The clamp member 53 clamps the sheet bundle Sl and linearly moves toward the back surface contact position H (without applying excessive stress to the sheet bundle Sl). At this time, the auxiliary guide plate 42 moves from the lower part of the aligning tray 41 to the vicinity of the back surface contact position H in parallel with the sheet bundle Sl at substantially the same speed substantially in association with the movement of the clamp member 53, and the sheet bundle Sl is moved. It guides the lower surface.

FIG. 8 shows a state in which the sheet bundle Sl is carried out from the alignment tray 41 by the clamp member 53. When the sheet bundle Sl is carried out of the alignment tray 41 by the clamp member 53, the auxiliary guide plate 42
Returns to the position of the abutting member 59, the stop finger 55 retreats from the storage position to the retreat position, positions the stored sheets S in the alignment tray 41, and carries them into the alignment tray 41. The incoming sheets S are aligned.

FIG. 9 shows a state in which the sheet bundle S1 is set to the back contact position H by the clamp member 53. The sheet bundle S1 is clamped by the clamp member 53,
While being guided by the auxiliary guide plate 42 on the lower surface, the auxiliary guide plate 42 linearly moves (without applying unnecessary stress) to set the back contact position H. The distance between the butting member 59 and the heater 56 (H) is longer than the size of the sheet bundle S1 to be bound.

FIG. 10 shows the lower surface of the auxiliary guide plate 42.
The completed bookbinding product S1 is transferred to the delivery position to the carriage 60 by the clamp member 53 while being guided by the guide. The carriage 60 has a rear contact position H.
While the sheet bundle S1 is bound by the carriage 60,
A sheet bundle supporting rod 805 inside and a sheet bundle rear end supporting plate 80
4 rotates about the rotation axis, and the sheet bundle support rod 80
5 supports the lower surface of the sheet bundle S1 together with the auxiliary guide plate 42 (the sheet bundle supporting rod 805 indicates an arrow D shown in FIG. 2).
Move in the direction).

After the bookbinding is completed, the bound sheet bundle S1 is
The clamp member 53 moves in the direction of arrow C (FIG. 2) to separate it from the heater 56. After that, the sheet bundle rear end support plate 804 moves between the pulled-up sheet bundle end portion and the heater 56. After that, the clamp member 53 is separated from the sheet bundle S1, and the end of the sheet bundle S1 abuts on the sheet bundle rear end support plate 804, so that the movement in the arrow B direction (FIG. 2) is blocked.

Then, the sheet bundle supporting rod 805 further moves to support the lower surface of the sheet bundle S1 only by the sheet bundle supporting rod 805. Then, the clamp member 53 and the auxiliary guide plate 42 return to the alignment tray 41. Sheet bundle S1
However, since the sheet supporting rod 805 raises the sheet guide rod 805 in an upward direction above the moving path of the auxiliary guide plate 42, the clamp member 53 and the auxiliary guide plate 42 do not rub against the lower surface of the sheet bundle and reach the alignment tray 41. It is possible to return. In addition, the auxiliary guide plate 42 and the support rod 805 are formed in a tooth shape that is alternately displaced so that they can enter each other alternately. Then, the clamp member 53 and the auxiliary guide plate 42 are attached to the alignment tray 4
After returning to 1, the finished product S1 is grounded on the conveyor belt 803 (FIG. 10).

FIG. 11 shows a state where the finished bookbinding product is stored in the stacker 71. The bookbinding completed product Sl on the carriage 60 is stored in the stacker 71 by the conveyor belt 803 and the rear end pushing member 802. Further, when the bookbinding completed product Sl on the carriage 60 is not stored in the stackers 71 and 72, the bookbinding completed product Sl is supplied to the second discharge port 139.
From the aircraft.

In FIG. 12, the bookbinding completed product Sl discharged from the bookbinding device 203 is delivered to the elevator 25 in the lower part of the sorting and storing device 204, and the elevator 2
The bookbinding completed product Sl is stored in a predetermined discharge tray 30 by the vertical movement of 5. When it is unnecessary to store the bookbinding finished product Sl in the discharge tray 30, it is discharged as it is to the outside of the sorting storage device 204 via the elevator 25 located at the lowest position.

Further, when a sheet bundle for unbinding or sheets is discharged from the main body through the bookbinding apparatus to the sorting and storing apparatus, the carriage 60 moves below the bookbinding apparatus 203. Then, the unbound sheet bundle or sheets enter through the second carry-in port 91 located below the stacker 72, and the left lower transport path 92, the carriage 60, and the right lower transport path 93.
Through the second discharge port 139. With this configuration, when the unbound sheet bundle is discharged to the outside of the sorting storage device 204, the sorting storage device 20
It is possible to discharge the waste without passing through the transport path 26 of No. 4 (FIGS. 1 and 12).

Next, the operation of the online device 1 of the present invention will be described.

When the job designated by the controller CPU, which is the control means provided in the image forming unit 202, is switched to the next job, or when the interrupting job is temporarily entered, for example, a finishing device connected online is used. In some cases, the image forming apparatus has a multi-function function, is used as a printer by being connected to a workstation by a LAN or the like, is used as a FAX output, or is used as an output sorting means for various mails. However, these pieces of information are always sent to the controller CPU of the image forming unit 202 at random. Then, the image data is temporarily stored in the internal image storage memory, interrupts by starting the job operation by observing the timing of another job, and discharged to the paper discharge tray, the sample tray, or the sorting device.

In the above-described state, the image forming unit 202 and the online device 1 perform a plurality of jobs at the same time in order to substantially improve productivity and improve productivity. Therefore, the sheets fed in from the carry-in port A shown in FIGS. 3 and 4 are carried in as quickly as possible between different sheets of different jobs. However, switching the flapper 317 between these narrow sheets becomes a critical time critical path method, and therefore the flapper 31
The switching time of 7 is the required paper interval time. When this time is multiplied by the speed at which the sheet is conveyed,
It is the distance between the sheets. Therefore, in the present invention, focusing on this point,
A branch flapper means can be provided that can be switched at high speed regardless of paper intervals.

The sheet S entering from the arrow A is detected by the sensor 3
26 detects the flapper operation and the sheet timing, and establishes the standby of the finishing device arranged downstream. Flapper 317 between jobs
When a control command for switching is set, the sheet leading edge entered from the carry-in port 19a reaches the flapper 317, and as soon as the sheet passes through the flapper roller 318, the plunger solenoid 321 is switched and the flapper 317 operates in the sheet nipping direction. . At that time, while pushing up the sheet passing over the flapper, the flapper roller rotates while holding the sheet between the rollers on conveyance and waits for the sheet to pass. When the trailing edge of the sheet leaves the flapper roller 318, the flapper rotates to the state shown in FIG. 4 due to the suction force of the solenoid 321. When the flapper roller 318 at the leading end of the flapper 317 is near the timing of reaching the inside of the transport roller 319, the leading edge of the next sheet is immediately moved by the flapper 317 in the direction of arrow C as shown in FIG. Branch switching is performed so as to be guided and conveyed while rubbing the lower surface of 317.

As soon as the leading edge of the sheet passes through the flapper roller 318, the flapper 317 is switched, the sheet is urged between the lower roller 320 and the trailing edge of the sheet, and the spring 322 rotates the sheet to the position shown in FIG. To return.
Then, the sheet is conveyed by the nip rollers 324, 325.
Is conveyed by the conveyance guide plates 309 and 316, is conveyed in the direction of arrow C, and is connected to a downstream device.

By this switching method, the flapper 31
Since the tip portion of 7 only needs to move a short distance, high-speed flapper switching can be performed. Further, when the sheet passes, the flapper roller 318 is provided at the tip of the flapper 317 so that the flapper 317 can freely rotate. Therefore, the rubbing mark of the flapper 317 is not formed on the sheet surface, so that the image quality is not deteriorated. . Further, in a high-speed machine and a high-durability machine, there is a risk of failure due to wear of the flapper tip, but the flapper roller eliminates the concern of wear and saves maintenance work. Therefore, the slidable plastic such as POM is used in the low speed image forming machine, and the bearing is used in the high speed machine for optimization.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the image forming apparatus according to the present invention, there is provided a bypass transport path that directly connects the carry-in transport path for transporting the paper to the intermediate tray and the transport path for unloading the paper. The configuration will be described below. To do.

FIG. 13 is a schematic configuration diagram of an electrophotographic copying machine 500 which is a double-sided image forming apparatus according to the embodiment of the present invention. In the figure, 501 is a platen glass,
The original placed on the original illumination lamp 502 and the first original
Mirror 503, second mirror 504 and third mirror 505
Then, the image is scanned by the lens 6, the fourth mirror 7, and the CCD sensor 8. Reference numeral 509 denotes a laser scanner device. The scanned laser beam is reflected by the laser first mirror 510 and the laser second mirror 511, and is imaged on the photosensitive drum 512 to form an electrostatic latent image.

Reference numerals 519 and 520 denote paper feed cassettes, and the paper (transfer paper) fed from any one of them is a paper feed vertical path section which is a carry-out conveyance path provided with paper feed vertical path roller pairs 521 and 522, respectively. The toner image on the photosensitive drum 512 is conveyed by the second timing roller pair 524 and the first timing roller pair 525, and the toner image on the photosensitive drum 512 visualized by the developing device is sent to the transfer charging device at the same timing. Be done. The sheet on which the toner image has been transferred is conveyed by the conveyor belt 526 and sent to the fixing device 527. Then, the paper on which the toner image is fixed by the fixing device 527 is discharged onto the paper discharge tray 530 by the internal paper discharge roller pair 528 and the external paper discharge roller pair 529, and is sequentially stacked.

When the images to be formed are multiplex or double-sided, the sheet on which the image formation on the first side is completed is not discharged onto the discharge tray 530, but the flapper 531 controls the discharge vertical path roller. It is sent to the paper discharge vertical path unit 535, which is a carry-in transport path including the pairs 532, 533, and 534. In the case of forming a multiplex image, the paper leaves the paper discharge vertical path roller pair 534 and then is controlled by the flapper 536 to be the first flapper 537, the first roller pair 538, and the second roller pair 538.
Flapper 539, second roller pair 540, third flapper 5
41, a third roller pair 542, and a fourth flapper 543 are fed to the intermediate tray horizontal path portion 544.

The flapper described above is switched by the sheet branching device 300 described in the previous embodiment. When it is set to continuously form multiple images on a large number of sheets, the sheets are the first flapper 537 and the second flapper 53 of the intermediate tray horizontal path unit 544.
Of the ninth flapper 541, the fourth flapper 543, or the fourth flapper 543, it is guided by the flapper that is suitable for the size and fed onto the intermediate tray 545. Intermediate tray 545
The paper sent to the top of the sheet
6 is loaded to the position where it abuts the shutter 547.

On the other hand, in the case of forming a double-sided image, the paper leaves the paper discharge vertical path roller pair 534 and then the flapper 536.
Is fed to the transfer path portion 49 having the switchback roller pair 548 capable of controlling forward and reverse rotations, and then the switchback roller pair 548 is rotated in the reverse direction, and the flapper 536 guides the same as in the case of the above multiple image formation. Similarly, it is sent to the intermediate tray horizontal path unit 544.

When it is set to continuously form a double-sided image on a large number of sheets of paper, this is also done on the intermediate tray 545 as in the case of forming a multiple image on the large number of sheets of paper. The shutter 547 is loaded to a position where it abuts against the shutter 547.

When the sheets are stacked and stored on the intermediate tray 545, after the original on the original platen glass 501 is exchanged, the shutter 5 and the image forming start signal for the second time are sent.
The sheet 47 on the intermediate tray 545 is separated and re-fed by the action of the pickup roller 550, the feed roller 551, and the retard roller 552. The re-fed paper is conveyed by the re-feed path roller pair 553, is again conveyed by the paper feed vertical path unit 523, and is timed by the second timing roller pair and the first timing roller pair 525. An image on the second side is formed, and thereafter, it is passed through the fixing device 527 by the conveyance belt 526, and further discharged by the inner paper discharge roller pair 528 and the outer paper discharge roller pair 529 onto the paper discharge tray 530 and sequentially stacked. .

The above is a description of the configuration and operation in the case of forming multiplex images or double-sided images on a large number of sheets in succession. Next, multiplex images, double-sided images on one or several sheets A configuration and an operation in the case of forming will be described.

In this multiple-sided, double-sided image formation, the above-described multiple-sided, double-sided image formation is performed until an image is formed on the first side of the sheet and the sheet is sent to the intermediate tray horizontal path section 544. Is exactly the same as the case. First, the sheet sent to the intermediate tray horizontal path section 544 is sent to the bypass section 556, which is a bypass conveyance path including the bypass roller pair 555, and is again guided to the paper feed vertical path. At this time, the intermediate tray horizontal path section 5
44 first flapper 537, second flapper 539, third
Neither the flapper 541 nor the fourth flapper 543 operates and guides the sheet to the bypass section 556. That is, the sheet is not temporarily held in the intermediate tray 545 but is directly sent from the intermediate tray horizontal path section 544 through the bypass section 556 to the paper feed vertical path 523. Therefore, the time for forming the image on the second surface is shortened. Then, the paper fed to the paper feed vertical path 523 has the image formed on the second surface, and is ejected onto the paper ejection tray 530 sequentially in the same manner as in the case of the multiplex multiple-sided image formation described above. Loaded.

In the electrophotographic copying machine 500, the paper discharge vertical path portion 535 and the intermediate tray horizontal path portion 544, which start from the inner paper discharge roller pair 528 and end at the outlet roller pair 554, are the intermediate tray. A carrying path for carrying in the paper to the sheet 545. The paper feed vertical path portion that starts from the feed roller 551 and the retard roller 552 and ends at the second timing roller pair 524 is a carry-out conveyance path that carries out the paper from the intermediate tray 45. Furthermore, starting from the exit roller pair 554, the re-feed vertical path roller pair 5
The bypass section 556 ending at 53 includes the paper discharge vertical path section 535 and the intermediate tray horizontal path section 544 which are the above-mentioned carrying-in carrying path, and the paper feeding vertical path section 5 which is the above-mentioned carrying-out carrying path.
23 is a bypass conveyance path that directly connects the No. 23 and the intermediate tray 545. The feature of the electrophotographic copying machine 500 according to the present invention is that the bypass unit 556 is provided.

FIG. 14 is an explanatory diagram showing a state in which a multiple image is formed on four sheets of A4 size paper. In this figure, A4 size sheets Sl, S2, S3 and S4 are emphasized. As shown in the figure, the four sheets S1, S2, S3, and S4 on which the image formation on the first side is performed are respectively the paper discharge vertical path unit 535, the intermediate tray horizontal path unit, the bypass unit 556, and the paper feed vertical path unit 523. It may be arranged such that the respective rollers S1 and S2, S3, and S4 are conveyed again by making the respective rollers stand by by a signal for starting the image formation of the second surface.

Further, by using a document feeder or the like,
If the second-side image can be formed immediately after the first-side image is formed, the sheets S1, S2, S3, and S4 may be continuously conveyed toward the second-side image formation without being temporarily stopped. May be.

In the electrophotographic copying machine 500 which is the image forming apparatus according to the present invention, a small number of sheets Sl, S2, S are used.
When a multiplex image or a double-sided image is formed in S3 and S4, the image formation for the first side is completed and the carry-in conveyance path 535,
544), the paper transported by the intermediate tray 545
Transport paths 535 and 544 for carrying in without temporarily holding
Can be directly sent to the carry-out carrying path 523 through the bypass carrying path 556. Therefore, the time for image formation on the second surface can be shortened.

[0073]

As described above, according to the present invention, even when different jobs are continuously processed at different transport speeds, the job can be branched from the transport path to improve the processing speed in the finishing device downstream thereof. It is possible to branch with a minimum sheet-to-sheet size without changing the conveying speed in the corresponding sheet conveying path and without changing the distance between the sheets, thereby improving the productivity.

Even if the conveying speed after branching the sheet is different, the first conveying roller on the upstream side of the branching means is driven by the first power source to branch from the first sheet conveying path. By driving the first conveying roller in the formed second sheet conveying path with the second power source, and driving the first conveying roller with the first and second power sources via the free bearing, It is not necessary to switch the transport speeds of the first and second power sources, the apparatus can be simplified, and the cost can be reduced.

Further, in the double-sided image forming apparatus in which the image-formed sheet is conveyed to the intermediate tray and stacked and the image is formed again, the conveying path downstream from the branching means corresponds to the conveying speed upstream from the branching means. The speed is set differently, and in the image forming apparatus connected to the finishing device connected online, the conveying speed on the downstream side of the finishing device is set to a different speed from the conveying speed on the upstream side of the branching means. And the bypass speed from the carry-in port to the discharge port via the branching unit is equal to or higher than the transporting speed upstream of the branching unit. It has become possible to minimize the sheet transport time in.

Further, when passing through the inside of the finishing device which is not selected, the conveying speed can be set to a high speed, and when the sheet approaches the selected predetermined finishing device, it is decelerated to reach the specified speed. By providing the control means for adjusting, the operation time of the finishing means performed after branching can be controlled and adjusted depending on the sheet conveying speed, so that the image forming sheet can be protected in an emergency and the finishing means. Optimal high-speed processing can be performed depending on the state of.

Further, the branching means is a flapper which also serves as a sheet conveying guide, and the flapper roller of the rotating body is arranged at the tip of the flapper, and the conveying roller for the rotating body is arranged at a position facing the flapper roller, and the flapper roller is arranged on the flapper roller. When the conveyance lower rollers are arranged alternately at the opposite positions, the positions of the conveyance lower roller and the flapper sheet conveyance guide when the flapper retracts are the same position, or they rotate in the direction of further retracting from the same position. It is abused by making it movable or by having a branching means which is a structure that can guarantee a minimum gap through which the sheet can slip even if the flapper roller is in the direction of narrowing the guide gap with the roller on conveyance. The flapper's durability can be improved, and it is possible to prevent the conveyed sheets from being damaged. Improve the quality of forming the finished product can be achieved.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing an example of the overall configuration of an online apparatus for bookbinding using the winding bind tape of the present invention.

FIG. 2 is a vertical sectional view showing a detailed configuration of a bookbinding apparatus in the online apparatus.

FIG. 3 is a front view showing details of the sheet branching device according to the first embodiment.

FIG. 4 is a front view showing details of the seat branching device and showing an operating state of a flapper.

FIG. 5 is a side view showing a drive unit of the seat branching device.

FIG. 6 is a vertical cross-sectional side view illustrating an operation of aligning sheets on an alignment tray of the bookbinding apparatus.

FIG. 7 is a vertical cross-sectional side view for explaining the operation of moving the sheet bundle aligned on the alignment tray to the rear surface of the heater.

FIG. 8 is a vertical cross-sectional side view for explaining the operation of moving the sheet bundle aligned on the alignment tray to the rear surface of the heater.

FIG. 9 is a vertical cross-sectional side view for explaining the operation of moving the sheet bundle aligned on the alignment tray to the heater back surface.

FIG. 10 is a vertical cross-sectional side view for explaining the operation when the bookbinding completed product is delivered to the carriage.

FIG. 11 is a vertical cross-sectional side view showing a state in which the completed bookbinding product is stored in the upper stacker by the carriage.

FIG. 12 is a vertical cross-sectional side view showing a state in which the finished bookbinding product discharged from the bookbinding device is delivered to the elevator of the sorting and storing device.

FIG. 13 is a schematic configuration diagram of an image forming apparatus (electrophotographic copying machine) to which a second embodiment of the present invention is applied.

FIG. 14 is a diagram showing the image forming apparatus (electrophotographic copying machine)
Explanatory drawing which shows the state which has formed the multiplex image on four sheets of paper.

[Explanation of symbols]

1 Image Forming Device (Online Device) 15 Image Forming Body (Photosensitive Drum) 19 Sheet Conveying Path 19a Carrying In Port (First Carrying Inlet) 19b Discharge Port (First Discharge Port) 41 Tray Means (Finishing Means) (Sheet Alignment) Tray) 201 Reading / feeding device 202 Image forming unit 203 Bookbinding device (finishing device) 204 Sorting and storing device 300 Sheet branching device 301 First power source (first motor) 302 Second power source (second motor) ) 303 power transmission means (timing belt) 304 power transmission means (timing belt) 307 first sheet conveyance path (conveyance upper guide) 309 second sheet conveyance path (conveyance lower guide) (conveyance path) 310 first conveyance Roller 317 Dividing means (Flapper) (Sheet conveying guide) 317a Support shaft (Flapper shaft) 317b Conveying guide rib 3 8 Flapper Roll 319 Transport Top Roll 320 Transport Bottom Roll 321 Drive Means (Plunger Solenoid) 322 Return Spring 323 Rotating Arm 324 Second Transport Roller 325 Second Transport Roller 326 Detecting Means (Sensor) 327 Power Transmission Means (Timing Pulley) 327a One-way drive transmission member (one-way bearing) 328 Power transmission means (timing pulley) 329 Power transmission means (timing belt) 331 Power transmission means (timing pulley) 500 Double-sided image forming apparatus (electrophotographic copying machine) 523 Carry-out transport path (Paper feed vertical path section) 535 Carry-in transfer path (paper discharge vertical path section) 544 Intermediate tray horizontal path section 545 Intermediate tray 556 Bypass transfer path (Bypass section) CPU control means (controller) S sheet

Claims (15)

[Claims] 1. A sheet branching device comprising a first sheet transporting path for transporting a sheet to be sent, and a second transporting path for transporting a sheet branched from the first sheet transporting path by a branching unit, A first transport roller provided in the first sheet transport path upstream of the branching unit, a second transport roller that transports a sheet in the second sheet transport path, and a first transport roller. A first power source for driving, a second power source for driving the second transport roller, a power of the first power source in one direction to the first transport roller, and A unidirectional drive transmission member that unidirectionally transmits the motive power of the second motive power source to the first transport roller, wherein the unidirectional drive transmission member is a high speed one of the first and second power sources. Transmission of power on the rotation side to the first transport roller A sheet branching device characterized by: 2. A driving means for driving the branching means, a detecting means for detecting that a sheet has been fed to the first sheet conveying path, and a driving means based on a detection signal from the detecting means. The seat branching device according to claim 1, further comprising: a control unit that controls the control unit, the control unit controlling the first and second power sources at a preset rotation speed. 3. A sheet branch including a first sheet transport path for carrying in and transporting a sheet to be sent, and a second transport path for transporting a sheet branched from the first sheet transport path by a branching unit. In the apparatus, a first power source that drives the first transport roller of the first sheet transport path, and a second power source that drives the second transport roller of the second sheet transport path. The first transport roller upstream of the branching unit in the sheet transport direction is connected to the first power source and the second power source, and is configured by a power transmitting unit via a one-way drive transmitting unit. What has been done is a seat branching device. 4. A sheet detecting means is provided in a sheet conveying path upstream of the branching means in the sheet conveying direction,
4. The sheet branching device according to claim 1, further comprising control means for controlling the position of the branching means and the driving means for the sheet conveying path. 5. The first sheet conveyance path downstream of the branching means is a sheet conveyance path that passes through the inside of the apparatus, and the second sheet conveyance path downstream of the branching means can stack sheets. The sheet branching device according to claim 1, wherein the sheet branching device is connected to the tray means. 6. An image forming apparatus comprising an image forming unit and a sheet branching device for branching a sheet on which an image is formed by the image forming unit, wherein the sheet branching device is any one of claims 1 to 5. An image forming apparatus, wherein the image forming apparatus is a sheet branching apparatus according to the above item. 7. A double-sided image forming apparatus including an image forming unit, a sheet branching device for branching a sheet on which an image is formed by the image forming unit, and a bypass conveyance path for conveying the sheet to the image forming unit. The double-sided image forming apparatus according to claim 1, wherein the sheet branching device is the sheet branching device according to any one of claims 1 to 5. 8. A sheet on which an image has been once formed is conveyed to an intermediate tray by a conveyance path for stacking and stacked, and
In an image forming apparatus provided with an intermediate tray configured to re-feed the sheets stacked on the intermediate tray through the carry-out carrying path to form an image again, the carrying-in carrying path and the carrying-out carrying path are provided. An image forming apparatus having an intermediate tray having a bypass transport path directly connected to the bypass transport path and a sheet branching device capable of transporting a sheet are provided in the intermediate tray. An image forming apparatus, wherein a conveying path downstream of the apparatus is set so that a speed thereof is different from an upstream conveying speed by the sheet branching apparatus. 9. The image forming apparatus according to claim 8, wherein the sheet branching device is the sheet branching device according to any one of claims 1 to 5. 10. An image forming apparatus to which a finishing device connected online is connected, wherein the finishing device includes a sheet branching device provided between a carry-in port and a discharge port, and the sheet branching device is provided inside the finishing device. A conveying path leading to the finishing means, the conveying speed on the downstream side is set to a different speed with respect to the conveying speed on the upstream side of the sheet branching device, and the conveying path from the carry-in port through the sheet branching device. The image forming apparatus is characterized in that the bypass speed to the discharge port is equal to or higher than the conveying speed upstream of the sheet branching device. 11. The seat branching device is the seat branching device according to claim 1,
The image forming apparatus according to claim 10, wherein: 12. The height of the carry-in port and the discharge port can be set to the same height from the floor surface, and the discharge port of the final connection finishing device from the image forming unit is sequentially connected to the image forming unit. Even if multiple sheets are connected to each other, it is a bypass portion that can be conveyed in the sheet conveying path without passing through finishing means inside each finishing device, and when passing through an unselected finishing device, the conveyance speed is set to a high speed. 6. The control unit according to claim 1, further comprising a control means that can be set so that the sheet is decelerated when the sheet comes close to a selected predetermined finishing device and the sheet speed is adjusted to a prescribed speed. An image forming apparatus comprising a sheet branching device. 13. A branching unit for branching a sheet is a flapper that also serves as a sheet transport guide, and includes a rotating spindle, a transport guide rib extending from the spindle, and a roller of a rotating body at the tip of the flapper. A sheet branching device, wherein the flapper rollers are arranged, and a conveyance upper roller of the rotating body is arranged at a position facing the flapper roller of the sheet conveying guide member forming the branching portion. 14. The upper conveyance roller and the lower conveyance roller that face each other in the sheet conveyance path are alternately arranged, and the lower conveyance roller and the sheet conveyance guide of the branching means when the branching means operates and retracts. Even if the position is the same position, or it is rotatable in the direction to retract further from the same position, or the flapper roller is in the direction of narrowing the inter-guide gap of the transporting lower roller at the branch position The seat branching device according to claim 13, wherein the seat branching device has a configuration capable of guaranteeing a limited gap. 15. An image forming apparatus comprising an image forming section and a sheet branching apparatus for branching a sheet on which an image is formed by the image forming section, wherein the sheet branching apparatus is the sheet branching apparatus according to claim 13. An image forming apparatus characterized by being an apparatus.