JP6972818B2 - Paper reversing device, image forming system and program - Google Patents

Description

The present invention relates to a paper reversing device, an image forming system and a program.

Conventionally, there is known an image forming system in which an image forming apparatus for forming an image on paper is connected to a paper processing apparatus provided with a reversing mechanism for reversing the paper after image formation (see, for example, Patent Document 1).
There are various types of reversing mechanisms, and one of them is provided with a reversing path extending in the vertical direction in which a plurality of reversing rollers capable of forward and reverse rotation are arranged with respect to the main transport path extending in the horizontal direction. The composition is known. In the reversing mechanism having such a configuration, the reversing roller is rotated in the forward direction to advance the paper introduced from the main transport path to a predetermined position in the reversing path, and then the reversing roller is rotated in the reverse direction to reverse the paper in the reversing path. The paper can be reversed by returning from to the main transport path.

Japanese Unexamined Patent Publication No. 9-267961

However, such a reversing mechanism cannot introduce the next paper into the reversing path unless the rear end in the transport direction of the paper returned from the reversing path to the main transport path is completely removed from the reversing path.
For this reason, when the transport speed of the conveyed paper is high or the length of the paper in the transport direction is long, the succeeding paper is moved near the entrance of the reversing path until the preceding paper is completely removed from the reversing path. There is a problem that productivity cannot be improved because it is necessary to take measures such as making the paper stand by or widening the interval of the conveyed paper so that the paper does not have to wait.

The present invention has been made in view of the above problems, and is to improve the productivity in the paper reversal process.

In order to solve the above problems, the paper reversing device of the present invention is used.
The main transport route for transporting paper and
A reversing path that branches from the main transport path and has a plurality of reversing roller pairs that can rotate forward and backward,
The reversing roller pair is rotated in the forward direction to transport the paper introduced from the main transfer path to a predetermined position in the reversing path, and then the reversing roller pair is rotated in the reverse direction to move the paper from the reversing path to the main transport path. The control unit that sends out to
Equipped with
In the main transport path, an upstream roller pair that delivers the paper to the reversing path and a downstream roller pair that receives the paper sent out from the reversing path are arranged.
The control unit
After the tip of the first paper fed from the reversing path to the main transport path reaches the downstream roller pair, the rear end of the first paper in the transport direction is the reversing roller closest to the main transport path. At a predetermined timing before reaching the pair, at least the closest reversing roller pair among the plurality of reversing roller pairs is separated, and the subsequent second sheet is introduced into the reversing path by the upstream roller pair.
When the length of the first paper in the transport direction is shorter than the distance from the downstream roller pair to the nearest reversing roller pair, the reversing roller pair is not separated .

Further, the image forming system of the present invention is
An image forming device that forms an image on paper,
The paper reversing device for reversing the paper on which an image is formed by the image forming device, and the paper reversing device.
It is characterized by having.

Further, the program of the present invention is
The main transport route for transporting paper and
A reversing path that branches off from the main transport path and has a plurality of reversing roller pairs that can rotate forward and backward, is provided.
In the main transport path, an upstream roller pair that delivers the paper to the reversing path and a downstream roller pair that receives the paper sent out from the reversing path are arranged.
The reversing roller pair is rotated in the forward direction to transport the paper introduced from the main transfer path to a predetermined position in the reversing path, and then the reversing roller pair is rotated in the reverse direction to move the paper from the reversing path to the main transport path. The computer of the paper reversing device to be sent to
After the tip of the first paper fed from the reversing path to the main transport path reaches the downstream roller pair, the rear end of the first paper in the transport direction is the reversing roller closest to the main transport path. At a predetermined timing before reaching the pair, at least the closest reversing roller pair among the plurality of reversing roller pairs is separated, and the subsequent second sheet is introduced into the reversing path by the upstream roller pair. This is a program for functioning as a control unit that does not separate the reversing roller pair when the length of the first paper in the transport direction is shorter than the distance from the downstream roller pair to the nearest reversing roller pair.

According to the present invention, the productivity in the paper reversal process can be improved.

It is a figure which shows an example of the schematic structure of an image formation system. It is a block diagram which shows the main functional composition of an image forming apparatus and a paper reversing apparatus. It is a schematic diagram which shows the structure of the paper reversal part. It is a flowchart which shows the operation of the paper reversal part. It is a figure for demonstrating operation of a paper inversion part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Configuration of image formation system]
First, the configuration of the image forming system in the present embodiment will be described.

FIG. 1 is a diagram showing an example of a schematic configuration of the image forming system 1 of the present embodiment.
As shown in FIG. 1, the image forming system 1 includes an image forming device 3, a paper reversing device 5, and a paper processing device 7.

The image forming apparatus 3 is an apparatus for forming an image on paper by an electrophotographic method. The image forming apparatus 3 conveys the paper on which the image is formed to the paper reversing apparatus 5.
The paper reversing device 5 is a device for reversing the paper conveyed from the image forming device 3. The paper reversing device 5 conveys the reversed paper to the paper processing device 7. The paper reversing device 5 can also convey the paper to the paper processing device 7 without reversing the paper. It is also preferable that the paper reversing device 5 has a paper processing function other than reversing the paper.
The paper processing device 7 is a device that performs predetermined paper processing on the paper conveyed from the paper reversing device 5 and ejects the paper. Examples of the paper processing include decal processing, staple processing, punching hole processing, folding processing, bookbinding processing, and the like.
The image forming apparatus 3, the paper reversing apparatus 5, and the paper processing apparatus 7 described above are configured to be detachable from adjacent devices.

FIG. 2 is a block diagram showing the main functional configurations of the image forming apparatus 3 and the paper reversing apparatus 5.
Hereinafter, the image forming apparatus 3 and the paper reversing apparatus 5 will be described with reference to FIGS. 1 and 2.

<Image forming device>
The image forming apparatus 3 includes a control unit 30 having a CPU (Central Processing Unit) 301, a RAM (Random Access Memory) 302, and a ROM (Read Only Memory) 303, a storage unit 31, an operation unit 32, and a display unit 33. An external communication unit 34, an interface 35, a scanner 36, an image processing unit 37, an image forming unit 38, and a transport unit 39.
The control unit 30 is connected to the storage unit 31, the operation unit 32, the display unit 33, the external communication unit 34, the interface 35, the scanner 36, the image processing unit 37, the image forming unit 38, and the transport unit 39 via the bus 3b. There is.

The CPU 301 reads and executes a control program stored in the ROM 303 or the storage unit 31, and performs various arithmetic processes.

The RAM 302 provides a working memory space for the CPU 301 and stores temporary data.

The ROM 303 stores various control programs, setting data, and the like executed by the CPU 301. Instead of ROM 303, rewritable non-volatile memory such as EEPROM (Electrically Erasable Programmable Read Only Memory) or flash memory may be used.

The control unit 30 including the CPU 301, RAM 302, and ROM 303 collectively controls each unit of the image forming apparatus 3 according to the above-mentioned various control programs. For example, the control unit 30 causes the image processing unit 37 to perform predetermined image processing on the image data and stores the image data in the storage unit 31. Further, the control unit 30 conveys the paper to the conveying unit 39, and causes the image forming unit 38 to form an image on the paper based on the image data stored in the storage unit 31.

The storage unit 31 is composed of a DRAM (Dynamic Random Access Memory) or the like, and stores image data acquired by the scanner 36, image data input from the outside via the external communication unit 34, and the like. Note that these image data and the like may be stored in the RAM 302.

The operation unit 32 includes input devices such as a touch panel arranged so as to be superimposed on the operation keys and the screen of the display unit 33, and converts input operations for these input devices into operation signals and outputs them to the control unit 30.

The display unit 33 includes a display device such as an LCD (Liquid crystal display), and displays an operation screen or the like showing the state of the image forming system 1 or the content of an input operation on the touch panel.

The external communication unit 34 communicates with a computer on the network or another image forming apparatus according to a control signal from the control unit 30, and transmits / receives image data or the like.

The interface 35 is a means for transmitting and receiving data to and from the paper reversing device 5, and is configured by, for example, any of various serial interfaces.

The scanner 36 reads the image formed on the paper, generates image data including monochromatic image data for each color component of R (red), G (green), and B (blue), and stores the image data in the storage unit 31. ..

The image processing unit 37 includes a rasterization processing unit, a color conversion unit, a gradation correction unit, and a halftone processing unit. The image data stored in the storage unit 31 is subjected to various image processing and stored in the storage unit 31. ..

The rasterization processing unit converts vector format image data described in a predetermined page description language (PDL) input from a computer or the like on the network into raster format image data such as a bitmap. The image data converted and generated by the rasterization processing unit includes monochromatic image data for each of the C (cyan), M (magenta), Y (yellow), and K (black) color components.
The color conversion unit performs color conversion processing on the image data of each color of R, G, and B output from the scanner 36 with reference to a predetermined look-up table, and monochromatic image data of each color of C, M, Y, and K. Generate image data including. Further, the color conversion unit performs a predetermined color correction process on the image data.
The gradation correction unit sets the gradation value of the image data by referring to a look-up table in which the correction value corresponding to each gradation value is defined so that the gradation characteristic of the image related to the image data becomes a predetermined characteristic. to correct.
The halftone processing unit performs halftone processing such as screen processing using a dither matrix and error diffusion processing on the image data.
The rasterization processing unit, the color conversion unit, the gradation correction unit, and the halftone processing unit included in the image processing unit 37 may be partially or wholly realized by the control unit 30, or the image forming apparatus 3 may be used. It may be configured to be realized by another image processing device provided externally.

The image forming unit 38 forms an image on paper based on the image data stored in the storage unit 31. As shown in FIG. 1, the image forming unit 38 includes four sets of exposed units 381, a photoconductor 382, and a developing unit 383 corresponding to the color components of C, M, Y, and K, respectively. Further, the image forming unit 38 includes a transfer body 384, a secondary transfer roller 385, and a fixing unit 386.

The exposure unit 381 includes an LD (Laser Diode) as a light emitting element. The exposure unit 381 drives the LD based on the image data, irradiates the charged photoconductor 382 with a laser beam, and exposes the photoconductor 382 to form an electrostatic latent image on the photoconductor 382. The developing unit 383 supplies toner (coloring material) of a predetermined color (any of C, M, Y, and K) onto the photoconductor 382 by a developing roller charged on the exposed photoconductor 382. The formed electrostatic latent image is developed.
An image (monochromatic image) formed of the toners of C, M, Y, and K on each of the four photoconductors 382 corresponding to C, M, Y, and K is transferred from each photoconductor 382 onto the transfer body 384. It is sequentially stacked and transferred. As a result, a color image containing C, M, Y, and K as color components is formed on the transfer body 384.

The transfer body 384 is an endless belt wound around a plurality of transfer body transfer rollers, and rotates according to the rotation of each transfer body transfer roller.

The secondary transfer roller 385 transfers the color image on the transfer body 384 onto the paper fed from the paper feed tray 3a. Specifically, when a predetermined transfer voltage is applied to the secondary transfer roller 385 that sandwiches the paper and the transfer body 384, the toner forming the color image on the transfer body 384 is attracted to the paper side and becomes the paper. Transcribed.

The fixing unit 386 heats and pressurizes the paper on which the toner is transferred to perform a fixing process for fixing the toner to the paper. The fixing portion 386 includes a pair of rollers including a heating roller and a pressure roller for holding the paper. The heating roller is heated to a predetermined target temperature (for example, a temperature within the range of 180 ° C. or higher and 200 ° C. or lower) by a heater as a heating source. The pressure roller is urged toward the heating roller by an elastic member (not shown). The paper on which the image formed by the toner is transferred on the secondary transfer roller 385 passes through the nip portion between the heating roller and the pressure roller, so that the image formed by the toner is fixed on the paper.

The transport unit 39 includes a plurality of paper transport rollers for transporting the paper by rotating while sandwiching the paper, and transports the paper along a predetermined transport path. The transport unit 39 includes a resist roller 391 arranged on the upstream side of the secondary transfer roller 385 in the transport direction. The resist roller 391 temporarily stops the feeding of the fed paper, and adjusts the timing of feeding the paper to the secondary transfer roller 385. Further, the transport unit 39 is provided with a reversing mechanism 392 that reverses the front and back of the paper that has been fixed by the fixing unit 386 and transports the paper to the secondary transfer roller 385. In the image forming apparatus 3, when the image is formed on both sides of the paper, the front and back sides of the paper are inverted by the inversion mechanism 392, and when the image is formed on only one side of the paper, the front and back sides of the paper are inverted by the inversion mechanism 392. The paper is conveyed to the paper reversing device 5 without being reversed.

<Paper reversing device>
The paper reversing device 5 includes a control unit 50 having a CPU 501, a RAM 502, and a ROM 503, an interface 51, a transport unit 52, a humidifying unit 53, a decaler unit 54, a purge unit 55, and a paper reversing unit 20. Be prepared.
The control unit 50 is connected to the interface 51, the transport unit 52, the humidifying unit 53, the decaler unit 54, the purge unit 55, and the paper reversing unit 20 via the bus 5b.

The CPU 501 reads out and executes a control program stored in the ROM 503, and performs various arithmetic processes.

The RAM 502 provides the CPU 501 with a working memory space and stores temporary data. This temporary data includes various setting information related to processing of each part of the paper reversing device 5 (for example, paper reversing processing).

The ROM 503 stores various control programs, setting data, and the like executed by the CPU 501. A rewritable non-volatile memory such as an EEPROM or a flash memory may be used instead of the ROM 503.

The control unit 50 including the CPU 501, the RAM 502, and the ROM 503 collectively controls each unit of the paper reversing device 5 according to the above-mentioned various control programs. For example, the control unit 50 causes the paper reversing unit 20 to perform a paper reversing process of reversing the front and back of the paper based on the setting information stored in the RAM 502.

The interface 51 is a means for transmitting and receiving data to and from the image forming apparatus 3 as a communication unit, and is configured by, for example, any of various serial interfaces.

The transport unit 52 includes a plurality of transport roller pairs that transport the paper by rotating while sandwiching the paper, and transports the paper along the main transport path R1.
Each transport roller pair is a pair of pressure-welded rollers, and at least one of the rollers is rotationally driven through a drive mechanism mainly composed of an electric motor to rotate the paper while holding it, thereby transporting the paper. do.
In the following description, the transport roller pair arranged at the position where the paper is delivered from the main transport path R1 to the reverse path R2 (described later) of the paper reversing section 20 is referred to as an upstream roller pair 21 (see FIG. 3). ..
Further, the transport roller pair arranged at the position where the paper sent from the reverse path R2 of the paper reversal section 20 to the main transport path R1 is received is referred to as a downstream roller pair 22 (see FIG. 3).

The humidifying unit 53 is a mechanism for performing a humidifying treatment in which water is applied to the paper to humidify the paper.
The humidifying section 53 includes humidifying roller pairs 53a and 53b arranged so as to be arranged in the vertical direction, and water is applied to the paper when the paper to be horizontally transported along the main transport path R1 is sandwiched and conveyed.
For example, by performing a humidifying treatment on the paper charged by the application of the transfer voltage or static electricity generated during transportation by the humidifying unit 53, it is possible to prevent the occurrence of phenomena such as floating and sticking of the paper.
Of course, it is also possible to transport the paper without performing the humidification treatment by the humidifying unit 53.

The decaler portion 54 has a curved path 54a that branches downward from the main transport path R1 on the downstream side in the transport direction of the humidifying section 53 and joins the main transport path R1 on the downstream side in the transport direction of the paper reversing section 20. By transporting the paper along the curved path 54a, the decaler portion 54 corrects the posture of the paper that has been curled due to the transport, fixing heating, or the like.

The purge unit 55 includes a sub paper ejection path 55a connected to the reversing path R2 and a sub paper ejection tray 55b projecting to the outside of the paper reversing device 5 capable of loading the paper conveyed by the sub paper ejection path 55a. , Equipped with.
The purge unit 55 is used when a malfunction such as a jam occurs, and it is possible to convey the paper to the sub paper ejection path 55a via the reversing path R2 and store the paper on the sub paper ejection tray 55b. do.

The paper reversing unit 20 is a mechanism for reversing the front and back sides of paper that is horizontally transported along the main transport path R1.
In the present embodiment, as shown in FIG. 1, the paper reversing portion 20 is provided on the downstream side in the transport direction from the branch point to the curved path 54a in the main transport path R1.

FIG. 3 is a schematic view showing the configuration of the paper reversing unit 20.
As shown in FIG. 3, the paper reversing section 20 includes, for example, a reversing path R2 that branches from the main transport path R1 and extends upward in the vertical direction.
When the paper is inverted by the paper inversion unit 20, the switching gate G1 switches the transfer destination of the paper conveyed on the main transfer path R1 to the inversion path R2, and the paper is introduced into the inversion path R2. ..

The inversion path R2 includes a guide member that guides the paper, and the paper travels in the gap formed by the guide member.
The inversion path R2 has a straight portion R21 extending linearly upward in the vertical direction, a curved portion R22 curved toward the image forming apparatus 3 side in the vicinity of the inner upper surface of the apparatus, and horizontal along the inner upper surface of the apparatus. It has a horizontal portion R23 extending in the direction.
Further, the sub-paper ejection path 55a of the purge portion 55 is connected to the curved portion R22, and the destination of the paper conveyed through the straight-line portion R21 of the inversion path R2 is set to the sub-paper ejection path 55a as needed. It is possible to switch. For example, when a malfunction such as a jam occurs, it is possible to convey the paper to the sub paper ejection path 55a via the straight portion R21 of the reversing path R2 and eject the paper onto the sub paper ejection tray 55b. ..
Further, in the reversing path R2, a plurality of reversing roller pairs 23 capable of forward / reverse rotation are arranged at predetermined intervals. In the following description, the plurality of reversing roller pairs 23 may be referred to as reversing roller pairs 23a, 23b, 23c ... In order from the one closest to the main transport path R1.

Each of the reversing roller pairs 23 is a pair of pressure-welded rollers, and at least one of the rollers is rotationally driven through a drive mechanism 24 (see FIG. 2) mainly composed of an electric motor to rotate the paper in a sandwiched state. This conveys the paper.
The spacing between the reversing roller pairs 23 is set to be narrower than the length of the minimum size paper to be passed in the transport direction.
Further, each reversing roller pair 23 is configured to be able to switch between a pressure contact state forming a nip portion and a separated state forming a predetermined gap.
The reversing roller pair 23 is controlled by the control unit 50, rotates in the forward direction (rotation in the direction of arrow A in FIG. 3), transports the paper introduced from the main transport path R1 to a predetermined position in the reversal path R2, and then reverses. It is switched to rotation (rotation in the direction opposite to the arrow A in FIG. 3) to reverse the paper transport direction, and the paper is fed from the reverse path R2 to the main transport path R1. As a result, the paper is switched back and the front and back of the paper are reversed.

[Operation of paper reversing device]
Next, the paper reversing process performed in the paper reversing device 5 of the image forming system 1 having the above configuration will be described.
FIG. 4 is a flowchart showing the operation of the paper reversing unit 20 in the paper reversing process.
5 (a) to 5 (e) are diagrams for explaining the operation of the paper reversing unit 20.

First, when performing the paper reversal process based on the job information acquired in advance, the control unit 50 drives the switching gate G1 and uses the upstream roller pair 21 to drive the first sheet of paper (first sheet, hereinafter "the first sheet". Paper P1 ”) is introduced from the main transport path R1 to the reverse path R2 (step S101: see FIG. 5A).

Next, the control unit 50 rotates the reversing roller pair 23 in the forward direction to transport the paper P1 in the reversing path R2, and determines whether or not the rear end of the paper P1 in the transport direction has reached a predetermined position in the reversing path R2. (Step S102).
Here, the predetermined position is a preset position where the paper P1 can be switched back. For example, a sensor or the like may be provided on the inversion path R2, and it can be determined from the output signal whether or not the paper P1 has reached a predetermined position.

Then, when the rear end of the paper P1 in the transport direction has not reached a predetermined position (step S102: NO), the process of this step S102 is repeated.
On the other hand, when the rear end of the paper P1 in the transport direction reaches a predetermined position (step S102: YES), the control unit 50 reversely rotates the reversing roller pair 23 to reverse the transport direction of the paper P1 (step S103: FIG. 5 (b)).

Next, the control unit 50 determines whether or not the tip of the paper P1 in the transport direction has reached the downstream side roller pair 22 (step S104), and if not (step S104: NO), the process of this step S104. repeat.
On the other hand, when the tip of the paper P1 in the transport direction reaches the downstream side roller pair 22 (step S104: YES), the control unit 50 stops the rotational drive of the reversing roller pair 23 (step S105).
At this time, since the paper P1 has already reached the downstream side roller pair 22, the paper P1 is conveyed to the downstream side of the main transfer path R1 by the downstream side roller pair 22.

Next, the control unit 50 determines whether or not the paper P1 being conveyed is the last paper for paper reversal processing (step S106), and if it is the last paper (step S106: YES), this processing. To finish.

On the other hand, when the paper is not the last paper (step S106: NO), the control unit 50 separates the number of reversing roller pairs 23 according to the length of the paper P1 in the transport direction in order from the one closest to the main transport path R1 (step S106: NO). Step S107: See FIG. 5 (c)).
Specifically, the control unit 50 separates the reversing roller pair 23, which is in a state of sandwiching the paper P1, when the tip of the paper P1 in the transport direction reaches the downstream side roller pair 22.
For example, the length of the paper P1 in the transport direction is the sum of the distance from the downstream roller pair 22 to the reversing roller pair 23a (L1) and the distance from the reversing roller pair 23a to the reversing roller pair 23b (L2). If it is shorter than the length, only the reversing roller pair 23a is separated.
Further, the length of the paper P1 in the transport direction is longer than the combined length of L1 and L2, and the combined length of L1 and L2 and the distance (L3) from the reversing roller pair 23b to the reversing roller pair 23c. If it is shorter than that, the reversing roller pair 23a and the reversing roller pair 23b are separated from each other.
When the length of the paper P1 in the transport direction is shorter than that of L1, the reversing roller pairs 23 are not separated from each other.

Next, the control unit 50 introduces the second sheet (second sheet, hereinafter referred to as “paper P2”) from the main transfer path R1 to the reversal path R2 by the upstream roller pair 21 (step S108: FIG. 5). See (c)).
At this time, the control unit 50 controls the paper P2 so that the tip of the paper P2 in the transport direction reaches the nip portion of the reversing roller pair 23a at the timing of step S110 described later (timing at which the separated reversing roller pairs 23 are crimped). Adjust the transport speed of.
As a result, before the paper P1 is completely removed from the reversing path R2, the subsequent paper P2 enters the reversing path R2, and the paper P1 and the paper P2 pass each other in the reversing path R2 (straight line portion R21). Become.

Next, the control unit 50 determines whether or not the rear end of the paper P1 in the transport direction has passed the position corresponding to the nip portion of the reversing roller pair 23a (step S109), and if not, (step S109). : NO), the process of this step S109 is repeated.

On the other hand, when passing (step S109: YES), the control unit 50 crimps the separated reversing roller pair 23 to start forward rotation (step S110: see FIG. 5D), and proceeds to the above step S102. .. When a plurality of reversing roller pairs 23 are separated from each other, all the separated reversing roller pairs 23 are simultaneously crimped.
At this time, as described above, the tip of the paper P2 in the transport direction reaches the nip portion of the reversing roller pair 23a at the timing of crimping the separated reversing roller pair 23. Therefore, the paper P2 is conveyed on the reversing path R2 by the reversing roller pair 23a (see FIG. 5E).

At the timing of step S110, the position at which the tip of the paper P2 in the transport direction reaches can be appropriately set according to conditions such as the distance between the rollers, as long as the transport stability is not affected. In addition to the above example, for example, at the timing of step S110, control may be performed such that the tip of the paper P2 in the transport direction reaches a position between the reversing roller pair 23a and the reversing roller pair 23b.

As described above, according to the present embodiment, the main transport path R1 for transporting the paper and the reversing path R2 having a plurality of reversing roller pairs 23 branching from the main transport path R1 and capable of forward / reverse rotation are inverted. After rotating the roller pair 23 in the forward direction and transporting the paper introduced from the main transport path R1 to a predetermined position in the reversing path R2, the reversing roller pair 23 is rotated in the reverse direction to transfer the paper from the reversing path R2 to the main transport path R1. A control unit 50 for feeding is provided, and an upstream roller pair 21 for delivering paper to the reversing path R2 and a downstream roller pair 22 for receiving the paper fed from the reversing path R2 are arranged in the main transport path R1. Then, in the control unit 50, after the tip of the paper P1 sent from the reversing path R2 to the main transport path R1 reaches the downstream roller pair 22, the rear end of the paper P1 in the transport direction is closest to the main transport path R1. At a predetermined timing before reaching the reversing roller pair 23a, at least the reversing roller pair 23a among the plurality of reversing roller pairs 23 is separated, and the subsequent paper P2 is introduced into the reversing path R2 by the upstream roller pair 21.
Therefore, by separating the reversing roller pair 23 from each other, the subsequent paper P2 can be introduced into the reversing path R2 so as to pass the paper P1 sent out from the reversing path R2.
Therefore, the productivity in the paper reversal process can be improved.

Further, according to the present embodiment, the control unit 50 separates the number of reversing roller pairs 23 corresponding to the length of the paper P1 in the transport direction in order from the one closest to the main transport path R1 at the predetermined timing. ..
Specifically, the control unit 50 separates the reversing roller pair 23, which is in a state of sandwiching the paper P1, when the tip of the paper P1 in the transport direction reaches the downstream side roller pair 22.
Therefore, an appropriate reversing roller pair 23 is separated according to the length of the paper P1 in the transport direction.

Further, according to the present embodiment, the control unit 50 separates the reversing roller pair 23 when the rear end of the paper P1 in the transport direction passes through the position corresponding to the nip portion of the reversing roller pair 23a. It is crimped to start forward rotation.
Therefore, the separated reversing roller pairs 23 can be quickly returned to the subsequent conveying operation of the paper P2.

Specific details such as the configuration and control shown in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

For example, in the above embodiment, when the rear end of the paper P1 in the transport direction reaches a predetermined position, the rotational drive of the reversing roller pair 23 is stopped and the reversing roller pair 23 is separated. If the tip of the paper P1 in the transport direction reaches the downstream side roller pair 22 and the rear end of the paper P1 in the transport direction reaches the reversing roller pair 23a, the rotational drive of the reversing roller pair 23 is stopped and the reversing roller pair is stopped. The timing at which the separation of 23 is executed can be arbitrarily set.
For example, when the remaining length from the downstream roller pair 22 to the rear end of the paper P1 in the transport direction becomes a predetermined value or less, the rotational drive of the reversing roller pair 23 is stopped and the reversing roller pair 23 is separated. You can do it.

Further, in the above embodiment, in steps S109 and S110, when a plurality of reversing roller pairs 23 are separated from each other, the control of crimping all of them at once has been described as an example. The roller may be sequentially crimped from the roller whose rear end has passed the position corresponding to the nip portion, and the rotation in the positive direction may be sequentially started.

Further, for paper whose length (total length) in the transport direction is equal to or less than a predetermined value, it may be set not to separate the reversing roller vs. 23.
That is, when the length of the paper in the transport direction exceeds a predetermined value, at least the reversing roller pair 23a is separated, but when the length of the paper in the transport direction is equal to or less than the predetermined value, the reversing roller pair 23 (reversing roller pair). (Including 23a) is not separated.
By doing so, when the length of the paper P1 in the transport direction is not more than a predetermined value and the time from the separation of the reversing roller pairs 23 to the crimping is shortened, the productivity is not significantly affected. Therefore, the reversing roller vs. 23 are not separated from each other. Therefore, efficient control becomes possible.

Further, the purge unit 55 may be used for the paper reversal process depending on the length of the paper in the transport direction.
For example, in the case of paper such as so-called long paper in which the length of the paper to be inverted in the transport direction exceeds 1000 mm, the transport direction is switched to the sub paper discharge path 55a instead of the horizontal portion R23, and the sub paper discharge tray is used. It can be configured to be temporarily discharged on 55b.
With such a configuration, it is possible to perform paper reversal processing even for paper having a long length in the transport direction.

Further, the reversing path R2 of the paper reversing section 2 may be configured to extend downward in the vertical direction of the main transport path R1.
Further, it goes without saying that the paper reversing device 5 may be configured not to include any or all of the humidifying section 53, the decaler section 54, and the purging section 55.

1 Image formation system 3 Image formation device 5 Paper reversing device 20 Paper reversing unit 21 Upstream roller pair 22 Downstream roller pair 23, 23a, 23b, 23c Reversing roller pair 24 Drive mechanism 50 Control unit 55 Purge unit 55a Sub paper ejection path 55b Sub paper discharge tray R1 Main transport path R2 Inverted path R21 Straight section R22 Horizontal section R22 Curved section

Claims (6)

The main transport route for transporting paper and
A reversing path that branches from the main transport path and has a plurality of reversing roller pairs that can rotate forward and backward,
The reversing roller pair is rotated in the forward direction to transport the paper introduced from the main transfer path to a predetermined position in the reversing path, and then the reversing roller pair is rotated in the reverse direction to move the paper from the reversing path to the main transport path. The control unit that sends out to
Equipped with
In the main transport path, an upstream roller pair that delivers the paper to the reversing path and a downstream roller pair that receives the paper sent out from the reversing path are arranged.
The control unit
After the tip of the first paper fed from the reversing path to the main transport path reaches the downstream roller pair, the rear end of the first paper in the transport direction is the reversing roller closest to the main transport path. At a predetermined timing before reaching the pair, at least the closest reversing roller pair among the plurality of reversing roller pairs is separated, and the subsequent second sheet is introduced into the reversing path by the upstream roller pair.
A paper reversing device characterized in that when the length of the first paper in the transport direction is shorter than the distance from the downstream roller pair to the nearest reversing roller pair, the reversing roller pair is not separated. Claim 1 is characterized in that, at the predetermined timing, the control unit separates a number of reversing roller pairs corresponding to the length of the first paper in the transport direction in order from the one closest to the main transport path. The paper reversing device described in. The control unit is characterized in that, when the tip of the first paper in the transport direction reaches the downstream roller pair, the reversing roller pair in which the first paper is sandwiched is separated. 2. The paper reversing device according to 2. When the rear end of the first paper in the transport direction passes through the position corresponding to the nip portion of the nearest reversing roller pair, the control unit crimps the separated reversing roller pair to perform forward rotation. The paper reversing device according to any one of claims 1 to 3, wherein the paper reversing device is started. An image forming device that forms an image on paper,
The paper reversing device according to any one of claims 1 to 4 , wherein the paper on which an image is formed is reversed by the image forming device.
An image forming system characterized by comprising. The main transport route for transporting paper and
A reversing path that branches off from the main transport path and has a plurality of reversing roller pairs that can rotate forward and backward, is provided.
In the main transport path, an upstream roller pair that delivers the paper to the reversing path and a downstream roller pair that receives the paper sent out from the reversing path are arranged.
The reversing roller pair is rotated in the forward direction to transport the paper introduced from the main transfer path to a predetermined position in the reversing path, and then the reversing roller pair is rotated in the reverse direction to move the paper from the reversing path to the main transport path. The computer of the paper reversing device to be sent to
After the tip of the first paper fed from the reversing path to the main transport path reaches the downstream roller pair, the rear end of the first paper in the transport direction is the reversing roller closest to the main transport path. At a predetermined timing before reaching the pair, at least the closest reversing roller pair among the plurality of reversing roller pairs is separated, and the subsequent second sheet is introduced into the reversing path by the upstream roller pair. A program for functioning as a control unit that does not separate the reversing roller pair when the length of the first paper in the transport direction is shorter than the distance from the downstream roller pair to the nearest reversing roller pair.

Images