JP2000026001A - Sheet conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a sheet inward and outward simultaneously and to positively reverse and convey the sheet without the sheets interfering with each other at the time of conveying the sheet into a switchback conveying path and then reversing the conveyed direction to convey the sheet outward. SOLUTION: A sheet conveying device is provided with a carry-in conveying means 57 for conveying a sheet P into a switchback conveying path 55 by sucking the sheet P to a carry-in belt 57c by air suction from a suction port 60a provided at an air suction duct. At the time point of completing carry-in of the sheet P, a carry-out process is performed by sucking the sheet P to a carry-out belt 58 constituting a carry-out conveying means 58 provided corresponding to the carry-in conveying means 57, by air suction from a suction port 62a provided at an air suction duct 62. During this carry-out process, a following sheet P can be conveyed in, so that the sheets can be conveyed in and out at the same time, and both sheets can be positively conveyed in and out without the conveyed-out sheet interfering with the conveyed-in sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises means for performing switchback conveyance in which when a sheet on which an image is formed by an image forming apparatus is discharged, the sheet to be discharged is turned over and then discharged. To a sheet transport processing device.

[0002]

2. Description of the Related Art A digital copying machine, which is one type of image forming apparatus, has recently been commercialized as a multifunction machine having functions such as a printer mode and a facsimile mode in addition to a copy (copy) mode. In normal copy mode, face-up, that is, sheet-like paper is sequentially discharged with the image formed side up, but in printer mode or facsimile mode, face-down paper discharge with the image formed side down Is commonly done. That is,
In the normal copying mode, the original document is sent so that the image is formed in advance from the last page in consideration of the page order of the discharged image-formed sheet by using an automatic document feeder or the like. The sheet on which the image has been formed is discharged in a state where the page order is aligned.

On the other hand, when operating as a printer,
Usually, since image data is sequentially transferred from an external device, for example, a word processor or a personal computer, and further from a facsimile device, the image is formed from the first page. Therefore, if the copy mode,
The sheet is discharged in the posture as it is, and in the print mode, the page order is aligned by reversing the front and back surfaces of the sheet and discharging the sheet with the image forming surface down on the discharge tray.

[0004] In order to realize the sheet reversing function, there has been proposed, for example, Japanese Patent Application Laid-Open No. 5-310357. Briefly describing the configuration of the apparatus described in the above publication, as shown in FIG. 16, when the toner image on the photoconductor (101) is transferred onto the paper sent from the paper feed tray (100), the fixing device ( 102) and is discharged out of the apparatus. At this time, a paper discharge processing unit (103) for switching the paper discharge mode according to the copy mode or the printer mode is provided.

[0005] When the image forming apparatus is in the copy mode, the recording surface is directly turned up, passes through various transport rollers of the paper discharge unit (103), and is discharged from the paper discharge port (104) to the discharge tray (105). Is discharged. On the other hand, in the printer mode, the transport path can be switched, and once guided to the switchback transport path (106) via various transport rollers, and then the transport direction is switched by the switching means (107). The sheet is discharged onto the discharge tray (109) with the recording surface facing down via the sheet discharge port (108).

In the figure, reference numeral (110) denotes an intermediate unit for double-sided image formation which is detachably or integrally provided with the main body of the digital image forming apparatus (111). The intermediate unit (110) is connected to the image forming apparatus (11).
1) When an image is formed on both sides of a sheet by being attached to the main body, the image is formed via the above-described sheet discharging unit (103).
Furthermore, the toner image is conveyed to the intermediate tray (112) via the switchback conveyance path (106), and is sent again from this position to the transfer position of the photoconductor (101) on which the toner image has been formed.

Further, in order to form an image, a laser beam irradiation unit (113) is provided on the photoreceptor, and a reading unit (scanner 114) for optically reading an image of a document is provided at the top. . The scanner (114) converts the image of the document on the transparent platen (115) into an optical system (11).
An image is formed on the CCD (117) serving as a reading element via 6), whereby the image is read by photoelectric conversion.
By driving the semiconductor laser of the laser beam irradiation unit (113) based on the read image based on the data, an image is formed on the photoconductor.

Japanese Patent Application Laid-Open No. 63-280272 discloses a state in which a conveying means having an endless belt and an air suction means is provided at a position of a switchback conveying path 106 in FIG. When the rear end of the belt passes through the switching unit 107, the conveying direction of the endless belt is reversed so that the endless belt is discharged.

[0009]

As described above, the sheet transport processing apparatus having the function of reversing the sheet is provided with a switchback for reversing the front and back sides of the sheet on which the image is formed (sheet). The sheet is discharged through the transport path. For this reason, the next sheet cannot be fed into the switchback conveyance path while the sheet is reversed and being discharged. That is, at the point when the inverted sheet has passed through the switchback transport path, the next sheet is sent to the switchback transport path.

Therefore, the image forming apparatus cannot increase the image output speed because it is necessary to provide a large gap in the switchback conveyance path where the leading and trailing edges of the sheet do not overlap.

On the other hand, according to the configuration of the switchback conveyance path disclosed in Japanese Patent Application Laid-Open No. 7-187522, the sheet is conveyed by two rollers to two nips (a portion between the rollers) by three rollers. This is used to guide the sheet to the switchback conveyance path at one nip, and output the sheet from the switchback conveyance path to the discharge section at the other nip. According to such a configuration,
The preceding sheet is conveyed along the switchback conveyance path, and when the trailing edge passes, the sheet is guided to another nip portion, and the next succeeding sheet is concurrently with the reverse sheet discharge processing of the previous sheet. It is possible to lead the light to the switchback transport path. Therefore, the reversal carrying-out process of the output sheet can be performed continuously, and the interval between the sheets can be shortened. Therefore, the speed of the image output processing can be increased.

However, according to Japanese Patent Application Laid-Open No. Hei 7-187522, the leading edge of a sheet carried in the switchback transport path and the leading edge of a sheet carried out of the switchback transport path (when the switchback transport path is carried in). (Rear end) is likely to be caught, and there is a risk that a jam or the like may occur.

Further, it is conceivable that the leading edge of the sheet conveyed to the switchback conveyance path is caught by the sheet being carried out, and the leading end is broken or jammed. This is because the leading edge of the sheet being carried in is only nipped between the nips of the rollers on the carrying side and conveyed, and as the leading edge of the sheet moves away from the nip portion on the carrying side, the restraint of the sheet decreases, This phenomenon becomes prominent due to static electricity, curling of the sheet tip, and the like.

An object of the present invention is to improve sheet transportability in a switchback transport path for reversing the feeding direction of an image-formed sheet and to minimize the interval between sheets that can be processed. An object of the present invention is to provide a sheet conveyance processing device.

Further, an object of the present invention is to prevent the sheet from being caught, bent or curled at the leading end, and from being jammed even when the sheet is simultaneously loaded and unloaded into the switchback transport path. It is an object of the present invention to provide a sheet transport processing apparatus in which sheets carried out and carried in a back transport path do not interfere with each other.

Further, in the present invention, in order to improve the transportability of the sheet, the sheet is sucked and carried in or out, thereby achieving the object.

[0017]

According to a first aspect of the present invention, there is provided a sheet transport processing apparatus for loading a sheet into a switchback transport path, and after the transport, switches the sheet from the switchback transport accounting. In a sheet transport processing apparatus configured to perform reverse transport of a sheet by reversing the transport direction, the sheet is provided in the switchback transport path, and the sheet fed to the switchback transport path is suctioned with air to switch the sheet. A carry-in carrying means for carrying in the inside of the back carrying path, and a carry-out carrying means arranged to face the carrying-in carrying means and suctioning the sheet carried into the switchback carrying path by air and carrying out the sheet from the switchback carrying path. After the sheet is conveyed into the switchback conveyance path, the conveyed sheet is attracted to the unloading conveyance means. Characterized by comprising an air suction control means adapted to control the suction state of the air in.

According to the sheet transport processing apparatus configured as described above, when a sheet is fed into the switchback transport path, the sheet is transferred to the switchback transport path in a state where the sheet is sucked by the loading transport means. It is carried in. When the carrying-in operation is completed, the air suction by the carrying-out transporting means is started, and the sheet sucked by the carrying-in transporting means is attracted to the carrying-out transporting means. In this state, the sheet is conveyed through the switchback conveyance path in the opposite direction. Therefore, the sheet is turned over and the sheet is conveyed to a target position. During this unloading process,
Even if the next sheet is sent to the switchback conveyance path, the carry-in conveyance means is in a state where it can be carried in, and the sheet can be carried in by suction by air suction. In this case, the sheet is carried in and carried out with the air suctioned into the carrying-in and carrying / transporting means, so that the sheet tip or the like is not caught, curling or bending does not occur, and there is no danger of jamming.

According to the second aspect of the present invention, in the sheet transport processing apparatus having the above-described configuration, the air suction control unit is configured to control the side of the carry-in transport unit when the transport of the sheet by the transport unit is completed. Is characterized in that the air suction is stopped, and the air suction on the unloading / transporting means side is started, or the air suction force on the unloading / transporting means side is increased. With this configuration, the sheet is attracted to the carry-out / conveying means after the carrying-in is completed, and the carrying-in / transporting means can carry in the next sheet at this time. In other words, the sheet at that time can be sucked in by air and carried in. Therefore, the sheet loading and unloading processing can be performed more reliably in the switchback transport path, and the interval when the sheet is reversely transported can be reduced. In particular, in the state where the sheet is sucked to the carry-out side by the air suction, even if the next sheet is carried into the switchback conveyance path, the sheet is not sucked by the air. Therefore, the carry-in process can be performed immediately, the sheet interval can be reduced, and the process can be performed reliably.

According to a third aspect of the present invention, in the sheet transport processing apparatus having the above-described configuration, the sheet transported to the switchback transport path is moved to the unloading transport unit. If discharge means for discharging air from the carry-in / transport means side to the discharge / conveyance means side is provided, for a sheet that has been carried in,
By discharging the air from the carry-in / transport means side, the sheet is moved to the carry-out / transport means side, and the discharge processing can be performed by reliably sucking the sheet by the air suction at the carry-out / transport means side.

According to another aspect of the present invention, there is provided a sheet transport processing apparatus according to the present invention for loading a sheet into a switchback transport path, and after transporting the sheet, switches from a switchback transport accounting to a feed direction. In a sheet transport processing apparatus configured to perform reverse transport of a sheet by reversing and transporting the sheet, a sheet provided in the switchback transport path and adsorbing a sheet fed to the switchback transport path is sucked and switched to a switchback transport path. Carrying-in means for carrying in the sheet, carrying-out means for carrying out the sheet carried in the switchback carrying path, which is disposed to face the carrying-in means, and carrying out the sheet through the switchback carrying path; and carrying in by the carrying-in means. And a moving means for moving the set sheet toward the unloading and conveying means.

According to such a configuration, the sheet sucked in by the carry-in / transport means is forcibly moved by the move means to the carry-out / transport means side after the carry-in process is completed. Is done. As a result, the sheet which has been conveyed by the carry-out / convey means can be discharged with the feeding direction reversed.
In this process, the carry-in / transport means side can also carry in the carry-in process of the next sheet. Therefore, even in such a configuration, the sheet interval can be similarly reduced in the reverse conveyance of the sheet on the switchback conveyance path.

Therefore, in a sheet transport processing apparatus having the above-mentioned configuration, according to the invention described in claim 5,
The moving means is constituted by an extruding mechanism which is pushed out to the unloading / transporting means side via the switch-back conveying path to the carrying-in / transporting means side and is retracted during the carrying-in / transporting by the carrying-in / transporting means. . As a result, during the carry-in process, the pushing mechanism is retracted to the carry-in / transport means side, and does not hinder the carry-in process. When the carrying-in process is completed, the sheet is released from being attracted, and the pushing mechanism is pushed out to the carrying-out / conveying means side. Therefore, the sheet is reliably moved to the carry-out / transport means side, and the moved sheet is discharged by the carry-out / transport means.

[0024] In the sheet transport processing apparatus having the above-mentioned configuration, according to the invention of claim 6, the pushing mechanism is arranged such that the urging means separates the switchback transport path toward the unloading transport means. And maintain the extruded state,
When the sheet is adsorbed and carried in by the carry-in / transport means, if the sheet to be carried in is retracted to the carry-in / transport means side, and is configured to be pushed out by releasing the suction state of the sheet upon completion of the carry-in, In particular, there is no need for a mechanism for forcibly retracting the pushing mechanism toward the carrying-in / transporting means when carrying in the sheet. In addition, since the sheet is pushed out to the carry-out and transport means side by the suction release of the carry-in and transport means side, there is no need to control the movement of the sheet by measuring timing. Therefore,
The configuration is very simple, and the sheet can be moved to the carry-out / conveying means only by the mechanism.

According to the seventh aspect of the present invention, in the sheet carry-out processing apparatus having the above-described structure, the moving means forms a switchback transport path located further downstream of the carry-in transport means. Guide member,
With a simple configuration that is provided to be inclined on the side of the carry-in conveyance means, when the suction state of the carried-in sheet is released,
The sheet itself moves toward the unloading and conveying means due to the restoring force of the sheet. Therefore, since the restoring force of the sheet is effectively used, not only the configuration is extremely simplified, but also it is possible to surely move the sheet.

Further, in order to achieve the above-mentioned object of the present invention, a sheet transport processing apparatus according to claim 8 transports a sheet to a switchback transport path, and after transporting the sheet, reverses the feed direction from switchback transport accounting. In the sheet transport processing apparatus configured to perform the reverse transport of the sheet by carrying out the sheet, the sheet provided in the switchback transport path is sucked and fed into the switchback transport path into the switchback transport path. And a driving roller for discharging a sheet carried into the switchback conveyance path, which is disposed to face the carry-in conveyance means, and transporting the sheet by the carry-in conveyance means. During the loading process, the sheet which has been separated from the driving roller and has been loaded by the loading / transporting means is completed. Further comprising a driven roller for performing unloading process was held between the dynamic roller and said.

According to such a configuration, the sheet on which the carry-in processing is completed is reliably moved to the drive roller side by utilizing the operation in which one of the driven rollers constituting the carry-out / convey means presses against the drive roller. Becomes possible. Then, the sheet can be carried out while the driven roller is pressed against the driven roller. When the sheet is adsorbed and carried in by the carry-in / conveyance means, the driven roller is separated from the drive roller, and does not hinder the carry-in process.

According to the ninth aspect of the present invention, there is provided a sheet transport processing apparatus having the above-described configuration.
The driven roller is rotatably provided on a rotation lever rotatably supported on the carry-in / conveyance means side, and forcibly pushes the rotation lever to move the carried-in sheet to the drive roller side. If the driven roller is configured to be rotated and pressed against the drive roller, the driven roller is retracted to the carry-in conveyance means side during the sheet carry-in process, and the sheet fed into the switchback conveyance path is driven by the driven roller. There is no occurrence of jamming or the like. In particular, since the driven roller is rotatably provided, even if the driven roller protrudes from the conveyance surface of the carry-in conveyance means, it is rotated by the sheet to be carried in, so that no carry-in operation is disturbed. Further, the sheet that has completed the carrying-in operation is forcibly rotated by the movable lever, and is sandwiched between the driven roller and the driven roller when the driven roller is pressed against the driven roller. Therefore, the sheet unloading process is reliably performed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of each embodiment of a sheet transport processing apparatus having a processing function by guiding a sheet to a switchback transport path according to the drawings and reversing the sheet feeding direction. Therefore, a description will be given of an example in which the sheet transport processing apparatus is provided in an output sheet discharge processing unit of the image forming apparatus.

According to the present invention, a sheet conveyance processing device is provided in a paper discharge section of a digital image forming apparatus (copier) having, for example, a copy mode, a print mode, and a fax mode. FIG. 2 is a side view for explaining a first embodiment of the sheet transport processing apparatus according to the present invention. FIG. 2 is a perspective view showing an appearance in FIG. 1, and FIG. 3 is a carry-in and carry-out transport means provided in a switchback transport path. FIG. 4 is a diagram provided to explain the operation of the sheet reversing function of the sheet carry-out processing apparatus according to the first embodiment.

FIG. 5 shows the overall configuration of a digital image forming apparatus including the above-mentioned sheet transport processing apparatus according to the present invention. According to the present invention, a sheet conveyance processing device is provided at a sheet discharging portion of the image forming apparatus as shown in FIG. 5, but a function of inverting the sheet is required even when performing image formation on both sides of the sheet. A sheet conveyance processing device having the same configuration of the present invention described below can also be provided in that portion. Therefore, it is needless to say that the sheet conveyance processing apparatus of the present invention can be applied to such a portion as it is.

First, referring to FIG. 5, an image forming apparatus according to the present invention will be described. This digital image forming apparatus is a digital copying machine, and the copying machine main body 1 is roughly composed of a scanner unit 10 and a laser recording unit 30.

The scanner section 10 includes a document table 11 made of transparent glass, a transparent reading plate 12 arranged in parallel with the document table 11 for scanning (reading) an image of a document to be conveyed, and the reading plate 12. Automatic document feeder (RADF) 13 for automatically feeding and feeding a document to a document, and document image reading for scanning and reading an image of a document located on the document table 11 and the reading plate 12 Unit 14
It is composed of

The original image read by the scanner unit 10 is sent to an image processing circuit as image data, and predetermined image processing is performed on the image data.

The RADF 13 sets a plurality of documents at a time on the provided document tray 13a, and automatically feeds the set documents one by one to the reading plate 12. The reading plate 12 is provided with a pressing drum 13b, and conveys the fed sheet document if it is pressed against the reading plate 12. The RADF 13 has a switchback transport path 13c for feeding one side or both sides of the document to the reading plate 12 according to the operator's selection, and reads an image via the switchback transport path 13c. The transport path is configured to include a transport path for a one-sided original, a transport path for a two-sided original, and a transport path switching unit. Since the RADF 13 has been filed and commercialized in the past, no further description will be given.

In order to place a document on the document placing table 11, the above-mentioned RADF 13 is rotatably provided with one end pivotally supported, and is opened to expose the document placing table 11. In this state, a book document or the like is placed. The original placed on the original placing table 11 or one from the RADF 13
A reading unit 14 for reading an image of a document fed one by one and fed to the reading plate 12 includes a lamp reflector assembly 15 for exposing the surface of the document, and a photoelectric conversion element (CCD) 22 for reflecting a reflected light image from the document. A first scanning member 17 mounted with a first reflection mirror 16 for reflecting the reflected light from the original to guide the light to the original, and a reflected light image from the first reflecting mirror 16 is converted to a photoelectric conversion element (CCD) 22. Scanning member 20 on which second and third reflecting mirrors 18 and 19 are mounted for guiding the light to the mirror, and the reflected light image from the original is reflected by each of the above-mentioned reflecting mirrors 16, 18 and 19 as an electric image signal. Lens body 2 for forming an image on a device (CCD) 22 for converting into
1 and the above-mentioned CCD element 22 for converting a reflected light image from an original into an electric image signal.

The scanner unit 10 places a document to be read on the reading plate 12 and the document placing table 11 by feeding the document by the RADF 13, and reads the reading unit along the lower surface of the reading plate 12 or the document placing table 11. The document image is read by fixing or moving the document 14.

To read the image of the document sent to the reading plate 12, the first unit of the reading unit 14 is used.
The scanning member 17 and the second scanning member 20 are moved to the left position shown in FIG. 4 and held at that position. Then, as the document is conveyed on the reading plate 12, the document is sequentially scanned and imaged on the CCD 22, and an electric signal corresponding to the document image is output from the CCD 22, which is output as image data.

When reading and scanning an image of a document placed on the document table 11, the reading unit 14 moves along the document table 11 to start reading scanning from the top of the document table 11. By traveling the first scanning member 17 at a constant speed V from left to right in the drawing, the second traveling unit 20 is controlled to travel in parallel in the same direction at a speed of V / 2 with respect to the speed V. You. As a result, the placed document is sequentially focused on the CCD element 22 line by line to read the image.

The reading unit 1 reads the original image as described above.
The image data obtained by reading at 4 is sent to an image processing circuit, and after being subjected to various processes, is temporarily stored in a memory of the image processing circuit. The image is given to the recording unit 30 and an image is formed on the sheet by using a colorant, for example, a toner.

The laser recording unit (printer) 30 includes a sheet transport system for forming a sheet for forming an image, a laser writing unit 31, and an electrophotographic processing unit 32 for forming an image.

The laser writing unit 31 emits a laser beam in accordance with image data read from the memory after reading by the above-described reading unit 14 or image data transferred from an external device. A polygon mirror that deflects the laser beam at a constant angular velocity, and f-θ that corrects the laser beam deflected at the constant angular velocity so as to be deflected at a constant speed on the photosensitive drum 33 constituting the electrophotographic process unit 32.
It has a lens and the like.

The electrophotographic process unit 32 includes a charger 34, a developing unit 35,
A transfer unit and peeling unit 36, a cleaning unit 37, and a static eliminator (not shown) are provided.

On the other hand, the sheet conveying system includes a registration roller 38 for conveying the sheet P to a transfer position of the electrophotographic processing section 32 for performing the above-described image formation, in particular, a transfer unit 36, and the registration roller 38. A plurality of cassette paper feeders 39a, 39b for feeding the sheet P, a sheet transport path 40 for feeding the selected sheet P to the registration roller 38, and the sheet P is fed to a transfer position. I have.

The transferred sheet P is separated from the photosensitive drum 33 to fix an image carried on the sheet P, in particular, a toner image. The sheet is sent to a sheet transport processing device 5 having a reversing process function. Further, although not shown in the figure, in order to form an image again on the back surface of the sheet P, that is, to form an image on both sides of the sheet P, the sheet P
Before the sheet P is sent to the sheet conveyance processing device 5, the sheet P is guided to a reversing switchback conveyance path, the sheet P is turned over, and the sheet P is sent again to the registration roller 38 via the sheet conveyance path 40. .

In the sheet transport system, in particular, the cassette sheet feeding devices 39a, 39b,... Accommodate sheets of a predetermined size desired by the operator, and sheets of the size desired by the operator are stored. Selectively fed.

In the laser writing unit 31 and the electrophotographic processing unit 32, the image data read from the image memory is scanned by a laser beam by the laser writing unit 31 to form an electrostatic latent image on the surface of the photosensitive drum 33. It is formed as an image and is visualized by toner. The toner image formed on the surface of the photosensitive drum 33 is formed by transferring a sheet P of a size selected from any one of the above-described sheet feeding devices 39 via the sheet conveying path 40 to the registration roller 3.
Then, it is sent to the transfer position of the transfer unit 36 through the transfer unit 8. As a result, the toner image on the surface of the photosensitive drum 33 is transferred to the surface of the sheet P, and is sent to the fixing device 41. After the fixing is completed, the image formation is completed, and the present invention is output via the discharge roller 42 as an output sheet. Sheet transport processing device 5
Is sent to

(First Embodiment of Sheet Conveying Processing Apparatus)
Hereinafter, the sheet transport processing device 5 of the present invention mounted on or equipped with a digital image forming apparatus or the like will be described in more detail with reference to FIG. The sheet transport processing device 5
Is provided with a sheet reversing function and the like for receiving the output sheet P on which image formation has been completed in the above-described digital copying machine 1, processing it to align the image surfaces, and align the page order.

For this reason, it is possible to effectively post-process sheets on which images are formed in the order of image formation, in particular, in the order of the last page or the first page, according to the above-described print mode or fax mode. Further, in accordance with an instruction manually operated on the operation panel, it is possible to perform a process of reversing discharge or discharging in the same posture.

When an output sheet P on which image formation has been completed is fed from a discharge roller 42 provided in a sheet discharge section of the digital copying machine 1, the sheet P is transferred to a sheet receiving port as shown in FIG. (Conveyance entrance) 50 guides the sheet into the sheet transport processing apparatus 5. In particular, the sheet conveyance processing device 5 is detachably provided at the discharge section (position) of the image forming apparatus 1 described above, or is fixedly mounted at that position.

A first transport roller 51 for taking in the incoming sheet P into the transport processing device is provided at the entrance 50.
(See FIG. 5), and the first transport roller 51
A discharge path 52 is provided for feeding the sheet P conveyed in the above-described manner to a discharge tray 6 (see FIG. 5) provided in a state of being protruded to the outside in the same posture. A discharge roller 53 is provided to feed the sheet P conveyed along the discharge path 52 to the discharge tray 6.

The discharge tray 6 may be provided with aligning means for aligning sheets, stapling means for binding the finally discharged and aligned sheet bundle, and the like.

The discharge path 52 between the first transport roller 51 and the discharge roller 53, especially the first transport roller 5
On one side, a second transport roller 54 is provided. A detection sensor 7 for detecting the leading end or the trailing end of the output sheet P is provided between the first and second transport rollers 51 and 54. Further, a sheet discharge detection sensor 8 is provided to detect the leading edge of the sheet discharged by the discharge roller 53. Although FIG. 1 shows that the sheet discharge detection sensor 8 is disposed downstream of the discharge roller 53, the sheet discharge detection sensor 8 may be provided on the upstream side so that the sheet discharged by the discharge roller 53 can be detected. , An actuator is provided close to the discharge roller 53.
The first and second transport rollers 51 and 54, the discharge roller 5
3 is driven and controlled in the same direction as shown in FIG. 1 and is not driven in reverse rotation.

The sheet P is selectively guided to a switchback conveyance path 55 branched from the discharge path 52 in the middle of the discharge path 52, particularly, the discharge path 52 between the second conveyance roller 54 and the discharge roller 53. Switching member 56 is provided rotatably. The switching member 56 is provided such that the tip thereof is opposed to the second transport roller 54.
The discharge path 52 is pivoted between a position where it is closed and a position where it is opened. At the position of the switching member 56 shown in FIG. 1, the discharge path 52 on the downstream side of the second conveyance roller 54 is closed, and the switchback conveyance path 55 side is opened.

The switching member 56 is also provided on the switchback transport path 55 side so that the other end thereof corresponds. A flexible guide piece 56a such as a polyester film for guiding the sheet P to the switchback transport path 55 is provided at the end. When the switching member 56 is rotated to the position shown in FIG. 1, the switchback conveyance path 55 and the discharge path 52 on the discharge roller 53 side communicate with each other.

On the upstream side of the switchback conveyance path 55, sheet feeding conveyance means 57 for sucking air and conveying the sheet so as to adsorb and convey the sheet so as to face each other, and switchback conveyance the sheet. Route 5
5 and a sheet unloading conveyance means 58 are provided at a predetermined interval. Sheet transporting means 57
Are rollers 57a, 57 provided at the top and bottom in FIG.
For example, as shown in FIG. 3, a plurality of belts 57c are stretched at equal intervals between b. Similarly, the sheet carrying-out transporting means 58 is also constructed by stretching a plurality of belts 58c at equal intervals between rollers 58a and 58b provided at the top and bottom.

As shown in FIG. 4, the sheet carrying conveying means 57 is provided with a suction duct 60 having an air suction port 60a constituting an air suction means so as to correspond to the plurality of belts 57c. (The surface opposite to the surface on which the sheet is sucked). A discharge duct 61 having a discharge port 61b for discharging air is provided between the plurality of belts 57c, that is, in a portion where no belt exists.

In contrast to the sheet carrying-in transporting means 57, a plurality of carrying-out belts 58c constituting the sheet carrying-out carrying means 58 are provided at portions where the carrying-in belts 57c are not opposed to each other as shown in FIG. It is provided correspondingly. A suction duct 62 formed with a suction port 62a for sucking air is also provided on the back surface of the carry-out belt 58c. Suction port 6 formed in this suction duct 62
2a corresponds to the discharge port 61a for carrying in, and the discharge port 61a is formed small as shown in the figure. This will be described in detail below.

Loading and unloading belts 57c and 58
In c, a large number of air passage openings are formed in order to suck the sheet P by air, adsorb it on the belt surface, and convey it. Therefore, when air is sucked in the suction duct 60 on the sheet carrying conveyance means 57 side, the sheet P is attracted to the carrying surface of the carrying belt 57c through the suction port 60a. When the carry-in belt 57c is driven by the rollers 57a and 57b, the sheet P is carried into the switchback carrying path 55. The roller 57a is, for example, a driving roller, and the carry-in belt 57c is driven to run in the direction of the arrow in FIG.

On the side of the carrying-out means 58, the carrying-out belt 58c is driven by rollers 58a and 58b to travel in the direction of the arrow. Therefore, the sheet P conveyed into the switchback conveyance path 55 is sucked through the suction port 62a by the operation of the air suction duct 62, and is attracted to the conveyance belt 58c. It is carried out from the back conveyance path 55.

In the switchback conveyance path 55, the leading edge of the incoming sheet is regulated according to the size of the sheet P.
A regulating plate 63 for preventing further drop is provided. The restriction plate 63 is provided to be vertically movable in FIG. That is, when the size of the sheet P is small (the length in the sheet conveyance direction is small), the regulating plate 63 is raised, and when the size is large, it is lowered.

A mechanism for raising and lowering the regulating plate 63 will be described with reference to FIG.
The restricting plate 63 is provided so as to penetrate through a slit provided in a U-shaped guide plate 59 forming the above.
The restricting plate 63 is integrally connected on the back side of the slit transport path 63, and both ends thereof are fixed to two drive belts 64. The drive belt 64 includes two rollers 65,
It is stretched between the rollers 66, and the rotational force is transmitted to the upper rollers 65. Accordingly, when the roller 65 is driven to rotate forward or reverse, the regulating plate 63 is moved up and down.

In the configuration of the sheet transport processing apparatus 5 configured as described above, in order to deepen the understanding of the structure and the related operation thereof, the output sheet P on which the image has been formed from the image forming apparatus 1 will be described below. The processing operation, control, and the like will be described.

(Copy Mode) When the image forming apparatus 1 is operating in the copy mode, the normal output sheet P is discharged onto the discharge tray 6 with the surface on which the image is formed as it is.

For this reason, the digital copying machine 1 forms (copies) an image of a document. In this case, the digital copier 1
The document is sequentially conveyed by the RADF 13, the image is read, and the image is sequentially stored. At this time, RADF
On the 13th side, the document of the last page is usually conveyed, and the document is sequentially read from the image of the document and copied. This is because the output sheets P copied in order from the last page of the original
When the document is stored on the upper side, the sheet on which the image is formed is discharged in the same order as the page order of the document. Thus, in the page order of the manuscript,
They are aligned on the discharge tray 6.

When a copy operation is started to copy a document set on the RADF 13 with the copy mode set, the image of the last page is read from the memory, and the image is conveyed. The output sheet P is formed into a sheet transport processing device 5 of the present invention.
It is sent to.

Therefore, the output sheet P on which an image is formed
Is carried into the sheet transport processing device 5 from the transport entrance 50 via the first transport roller 51. The leading edge of this sheet is detected by the detection sensor 7, and preparation for feeding the sheet to the discharge path 52 is performed. In this case, the switching member 56 is controlled in advance so that the discharge path 52 is opened, that is, the transfer path 52 between the second transfer roller 54 and the discharge roller 53 is opened.

Accordingly, the sheet P is sequentially discharged to the discharge tray 6 by the discharge roller 53 with the discharge path 52 kept in the same posture, that is, with the image forming surface facing upward. By repeating this operation sequentially, the output sheets P are sequentially deposited on the discharge tray 6 with the image surface facing upward. If all the output sheets P corresponding to the bundle of originals are discharged, the output sheets P are aligned on the discharge tray 6 and stapled. Then, a process of discharging the next number of output sheets P is executed.

(Facsimile or Print Mode) In this mode, image data from an external device, for example, a facsimile device, a word processor, or a personal computer is generally transferred sequentially from the first page. Therefore, when the mode is set, the image formed on the sheet is sequentially formed from the first page to the last page.

The sheet transport processing device 5 prepares for reception according to the mode. For example, the switching member 56 is switched to the position shown in FIG. Therefore, the discharge path from the second transport roller 54 to the discharge roller 53 is closed,
The sheet can be guided to the switchback conveyance path 55. Further, since the sheet size to be used is also selected in advance, the regulating plate 63 is controlled to move up and down in accordance with the size. In particular, when the sheet P is in the switchback conveyance path 5
5, and the rear end of the sheet P is guided by the guide piece 5 of the switching member 56.
The movement is controlled to a position outside 6a.

Therefore, the output sheet P on which an image has been formed is
By being transported by the first transport roller 51, the leading end is detected by the detection sensor 7. As a result, first, the carry-in transport means 57 starts operating. That is, air is sucked from the suction port 60a by the air suction duct 60, and the carry-in belt 57c is driven to run in the direction of the arrow.

Then, as shown in FIG. 4A, the sheet P is conveyed by the second conveying roller 54, and is fed to the switchback conveying path 55 along the guide surface of the switching member 56. The output sheet P is a guide piece 5 of the switching member 56.
By the operation of 6a, it is guided so as to face the carrying-in transporting means 57 side. The sheet P is sucked by the carry-in belt 57c because the sheet P is suctioned by air from the suction port 60a of the air suction means constituting the carry-in transfer means. As a result, as shown in FIG. 4B, the toner is absorbed by the carry-in belt 57c of the carry-in carrying means 57 and gradually carried into the switchback carrying path 55.

The trailing end of the conveyed sheet P is detected by the detection sensor 7. From the time of this detection, the rear end of the sheet P is carried into the switchback conveyance path 55,
The timing to reach the position shown in FIG. 4B or 4C can be known. That is, the time required to reach the above-described position from the time when the trailing edge is detected is determined by the distance and the transport speed if the transport speed is the same. Therefore, after that time (a certain time), the leading end of the sheet P is in contact with the regulating plate 63. Therefore, the fixed time (the timing)
, The carrying belt 57c on the carrying means 57 side
Is stopped as shown in FIG. At the same time, as shown in FIG. 4 (c), air is discharged from the discharge port 61a in the discharge duct 61 on the carry-in transfer means 57 side, and at the same time, the suction port 62 is formed in the suction duct 62 on the carry-out transfer means 58 side.
Air suction is performed from a. As a result, the sheet P for which the carrying-in process has been completed is moved from the carrying-in carrying means 57 to the carrying-out belt 58c of the carrying-out carrying means 58, as shown in FIGS.

In this case, as shown in FIG. 1 and FIG.
a, especially in the sheet carrying direction, on the upstream side, and the discharge port 61a is provided on the downstream side. Therefore, as shown in FIG. 4C, the suction port 60a is not completely covered with the sheet P, and a part thereof is opened. Thereby, if the suction port 60a is
Thus, even if air suction is continued, the sheet P is blown out of the discharge port 61a side, and further, the sheet P is sucked by the air suction port 62a of the unloading conveyance means 58 side as shown in FIG.
The sheet P can be reliably moved from the state (c) to the state (d). Further, the suction operation by the suction port 60a is stopped, and the suction and the blowing of the air by the suction port 62a and the discharge port 61a perform the movement of the sheet P more reliably.

When the sheet P is moved toward the unloading conveyance means 58 as described above, the unloading belt 58c is driven to travel as shown in FIG. 4D. Thus, the sheet P is conveyed in the reverse direction from the switchback conveyance path 55 and is carried out. Then, the sheet is guided to the rear side of the switching member 56, carried out to the discharge path 52, and discharged onto the discharge tray 6 via the discharge roller 53. At this time, the sheet P is discharged with the image side down.

Therefore, in FIG. 4D, at the time when the unloading of the sheet P is started, the next sheet P can be loaded into the switchback transport path 55. in this case,
Since the discharge of the air from the discharge port 61a of the carrying-in transporting means 57 is stopped, the switchback transport path 55
When the subsequent sheet P is fed as shown in FIG. 4A, the sheet P is brought into close contact with the carry-in belt 57c because the air is sucked at the suction port 60a, so that the carry-in processing is surely carried out. . This carrying in is performed without any hindrance by the carrying out operation of the preceding sheet P. Further, even if the preceding sheet P and the succeeding sheet P overlap in the switchback conveyance path 55, they are conveyed in a state of being sucked by the respective conveyance means 57, 58, so that they do not interfere with each other. The transfer process can be reliably performed without receiving an electrostatic action. Therefore, the leading edge and the trailing edge of the sheet to be carried in or out are not caught on each other, no curl or bending occurs, and there is no danger of jam.

In FIG. 4, the area indicated by the two-dot broken line corresponding to the discharge port 61a on the carrying-in / transporting means 57 side corresponds to the suction port 60a on the carrying-in / transporting means 58 side. It is.

(Another Aspect According to First Embodiment) According to the configuration of the sheet discharge processing apparatus 5 described above, an air discharge means, that is, a discharge port 61a is provided to the carry-in conveyance means 57 side.
Is provided. Therefore, as shown in FIG. 4C, when the operation of loading the sheet P into the switchback transport path 55 is completed, air is blown out from the discharge port 61a through the discharge duct 61, and the sheet P is transported to the transporting means 58 side. To move to

However, the above-described sheet reversing and conveying function can be provided without providing the air discharging means for moving the sheet P. That is, FIG.
In the state (1), when the operation of loading the sheet P is completed, the air suction operation by the suction duct 60 on the side of the transporting means 57 is stopped. Then, the carrying out means 58 for carrying out
By operating the suction duct 62 on the side, air suction is started from the suction port 62a. As a result, FIG.
As shown in (d), the sheet P conveyed into the switchback conveyance path 55 is moved to the conveyance means 58 for unloading.

In this state, by starting the carry-out operation by the carry-out carrying means 58, the carry-in operation of the next sheet P into the switchback carrying path 55 can be started. Therefore, the air suction operation is restarted by the suction duct 60 that has been temporarily stopped. At this time, since the previous sheet P during the unloading operation is air-adsorbed to the unloading belt 58c side, it does not move to the unloading belt 57c side due to the air suction on the unloading side, and is newly sent. The incoming sheet P is sucked and the carry-in process can be performed reliably.

For this purpose, the sheet P conveyed by the second conveyance roller 54 can be guided by the guide piece 56a provided on the switching member 56 to the carry-in conveyance means 57 side. In other words, if the tip of the guide piece 56a is provided so as to face the carrying-in transporting means 57, the action is further promoted.

Therefore, in order to carry out the carrying-in process by the carrying-in carrying means 57 to the switchback carrying path 55 and to carry out the carrying-out sheet without fail, the air suction by the suction duct 60 is started. Alternatively, a specific example of a control mechanism constituting an air suction control unit for performing a stop will be described below.

In FIG. 2, one end 60b of the suction duct 60 is connected to a suction fan or the like for sucking air through a duct, though not shown in the figure. The structure of the suction fan will be described below.

In the vicinity of one end 60b of the suction duct 60, as shown in FIG.
An opening / closing valve 65 for opening and closing the air flow passage in 0 is provided. The on-off valve 65 has a shaft portion 65a so as to be rotatable.
Are rotatably supported by upper and lower walls. Shaft 65
a protrudes from the upper wall of the duct 60,
An opening / closing lever 66 is fixed to the protruding end.

As shown in FIG. 6, the opening / closing lever 66 is connected to a movable member 67 pivotally supported on the side wall of the suction duct 60 so as to pass through a long hole 67a formed at one end thereof. The movable member 67 is urged to rotate counterclockwise in FIG. 6 by a coil spring 68 provided between the movable member 67 and the suction duct 60.

Then, on the other end side of the movable member 67,
Similarly, a long hole 67b is formed.
The solenoid 69 fixed to the side wall of the suction duct 60
The connecting pin 70a provided at the tip of the plunger (operating rod) 70 is penetrated to connect the two. Therefore,
When the solenoid 69 is energized, the plunger 70 is attracted, and the movable member 67 is rotated clockwise against the urging force of the coil spring 68. Thereby, the opening / closing lever 6
By turning the valve 6, the open / close valve 65 is positioned in a broken line as shown in FIG. 7 to open the flow passage in the air suction duct 60. Therefore, when the power supply to the solenoid 69 is stopped, the on-off valve 6
5 is rotated to the position shown by the solid line, and the flow passage in the duct 60 is closed.

In FIG. 7, the on-off valve 65 is
In order to reliably shut off the flow of air while the flow passage in 0 is closed, that is, in contact with the inner surface,
A backing member 71 made of rubber or the like is provided at the contact portion.

As described above, according to the air suction control mechanism, when air is suctioned, the solenoid 69 is energized, and the suction formed corresponding to the carry-in belt 57c of the suction duct 60 is performed. Air suction is performed through the port 60a. Then, when the carry-out process by the carry-out belt 58c is started, the power supply to the solenoid 69 is stopped, and the air suction from the suction port 60a can be stopped.

An air suction control mechanism having the same configuration as that shown in FIGS. 6 and 7 is provided on the suction duct 62 constituting the air suction means on the side of the carrying-out transport means 58. Further, when the suction state of the plunger 70 can be controlled by changing the current supplied to the solenoid 69, the opening / closing angle of the on-off valve 65 can be adjusted. Thus, the air suction state can be adjusted.

Further, as for a suction fan constituting suction means for sucking air, for example, a configuration as shown in FIG. 8 can be adopted. Fans 74 and 75 are provided at both ends of a rotating shaft 73 of the fan motor 72. Each of the fans 74 and 75 is covered with a housing and has a suction opening 74a, 7a.
5a and discharge openings 74b and 75b are provided. Therefore, the suction openings 74a and 75a are
7 and the suction ducts 60 and 62 of the carrying means 58 for unloading. Thereby, air suction can be performed.

(Other Aspects According to First Embodiment) This aspect is for surely moving the sheet P carried into the switchback carrying path 55 to the carrying means 58 for carrying out. An example is shown in FIG. That is, the guide plate 59a of the switchback transport path that is provided continuously to the switchback transport path 55 formed between the carry-in transport means 57 and the unload transport means 58 is provided at an angle. That is, the guide 59a is provided to be inclined so as to be inclined toward the carrying-in conveyance means 57.

Therefore, the sheet P conveyed to the switchback conveyance path 55 is conveyed as it is by the suction operation of the conveyance means 57 for conveyance. The leading edge of the sheet P is guided by the inclined guide 59a, and the conveying means 5
7 is carried into the lower area. If the air suction by the suction port 60a of the suction duct 60 is stopped when the carrying-in operation of the sheet P is completed and the carrying-out operation on the carrying-out carrying means 58 side is started, the stiffness of the inclined sheet P is reduced. ,
That is, the rear end portion of the sheet P moves toward the unloading conveyance means 58 due to the restoring force of the sheet P to return to the original shape.

Therefore, when the air suction by the unloading conveyance means 58 is started, the sheet P is reliably transferred to the unloading belt 5.
8c, and the carry-out operation is started. When the start is performed, air suction by the configuration of the air suction control mechanism described with reference to FIGS. 6 and 7 is started, and the carrying-in operation of the next output sheet P is enabled.

According to the above configuration, the sheet P, which has been completely conveyed by a very simple configuration, is surely moved to the conveyer / conveying means 58 by utilizing the stiffness of the sheet itself. It becomes possible. In this case, the regulating plate 63 that regulates the leading end of the sheet P is provided with a direct portion without movably providing the movement on the curved portion of the guide 59a.
What is necessary is just to provide it movably in the linear part.

(Other Aspects According to First Embodiment) According to the sheet transport processing apparatus 5 of FIG. 1, at the time when the sheet is transported into the switchback transport path 55, the transport means 57 for transport is used.
In order to surely move from the side to the carrying-out carrying means 58, the carrying-in belt 57c constituting the carrying-in carrying means 57 is also required.
Between the discharge duct 61 and the discharge port 61a
Without providing a pushing mechanism. This aspect will be described with reference to FIG.

In FIG. 10, an extruding mechanism 76 is provided corresponding to the portion of the discharge duct 61 in FIG. 1 where the discharge port 61a was provided. The push-out mechanism 76 is configured such that a roller 79 is rotatably provided on a support member 78 urged by a spring 77 toward the carrying-out conveying means 58. When the sheet P is brought into close contact with the carry-in belt 57c by the air suction by the carry-in carrying means 57, the spring 77 is set to a biasing force so that the pushing mechanism 76 is retracted (retractable) to the carry-in carrying means 57 side. ing.

By providing such an extruding mechanism 76,
If the air suction on the carrying-in transport means 57 is released at the time when the sheet P carrying-in process is completed, the sheet P can be reliably moved to the carry-out carrying means 58 side.

The operation will be described below.
As shown in (a), when the sheet P is fed into the switchback conveyance path 55, the sheet P is brought into close contact with the belt 57c by the traveling of the carry-in belt 57c of the carry-in carrying means 57 and the air suction of the suction port 60a. Comes in. At this time, the extruding mechanism 76 positioned in the protruding state is gradually pushed (retracted) into the carrying surface of the carrying-in carrying means 57 by the carried-in sheet P. This state is shown in FIG.

Then, when the process of loading the sheet P into the switchback transport path 55 is completed (at a certain time after the detection of the trailing edge of the sheet P by the detection sensor 7).
Then, the air suction by the suction means constituted by the suction duct 60 and the like is stopped. This stops the power supply to the solenoid 69 as described above. As a result, the state in which the sheet P is attracted to the carry-in belt 57c is released, and the pushing mechanism 76 is protruded toward the carry-out carrying means 58 by the urging force of the spring 77.

Therefore, the sheet P for which the carry-in process has been completed is
It is moved as shown in FIG. Further, the air suction operation is started on the side of the unloading conveyance means 58, and the sheet P is transferred to the unloading belt 58.
c, and the sheet is discharged as shown in FIG. At this point, the carry-in belt 57 is used to allow the next sheet P to be carried into the switchback carrying path 55.
c is driven to travel.

As described above, the sheet P that has been completely loaded
Is reliably moved to the unloading conveyance means 58 side by the action of the pushing mechanism 76, and the unloading process is performed. In the loading process of the sheet P, the pushing mechanism 76 is retracted by the sheet P. However, since the roller 79 provided at the leading end of the loaded sheet P is rotatably provided,
Since the sheet P does not act as a load on the carried sheet, there is no damage in the carrying operation.

In FIG. 10, the rear end of the sheet P after the carrying-in process is not covered with the suction port 60a on the carrying-in means 57 for carrying-in. This is as described above,
Even if the suction operation is stopped, the sheet P is immediately transferred to the carrying belt 5.
When the close contact state of 7c is not released, a part of the suction port 60a is not covered with the sheet P, so that the suction force of the sheet P decreases. Therefore, the pushing operation by the pushing mechanism 76 is ensured, and the sheet P can be moved immediately.

Accordingly, as shown in FIG. 10, the carry-in air suction port 60a is provided so as to be located upstream of the carry-out suction port 62a in the sheet carry-in direction. The rear end of the sheet is the suction port 60a.
Has passed through the upstream end. The suction port 62a for unloading is entirely covered with the sheet P.

Therefore, as described in the above-described embodiments, the air ejecting mechanism 76 and the discharge port 61a are provided to move the sheet P toward the unloading conveying means 58 after the sheet P is completely loaded. Even if a difference due to the suction force is generated, the same operation can be performed. Therefore, as shown in FIG. 3, the carry-out belt 58c is
Are provided so as not to correspond to each other.
8c is provided more than the carrying belt 57c. If a suction port 62a is provided in each of the carry-out belts 58c, the air suction force on the carry-out belt 58c side becomes larger.

Therefore, when the air suction operation of the unloading conveyance means 58 is started at the time when the sheet conveyance processing to the conveyance means 57 is completed, the sheet is moved to the conveyance means 58 by air suction. Is done. In this case, if the air suction on the side of the carrying-in transporting means 57 is stopped, the moving can be performed more reliably. Further, by providing the loading suction port 60a side as shown in FIG. 10 (or also shown in FIG. 3), the action is further promoted. That is, a part of the suction port 60c on the loading side is not covered with the sheet P that has been loaded. Further, the suction force for unloading is increased, and the sheet P is moved toward the unloading conveyance means 58 by arranging the unloading conveyance means 58 as close as possible to the loading conveyance means 57 side. Is to be performed more reliably.

Here, the mechanism for controlling the air suction, that is, the air suction control means, controls the turning state of the on-off valve 65 as described with reference to FIGS. That is, the suction of the suction port 62a is started when the sheet P carrying-in process is completed. Then, the suction operation of the suction port 60a on the loading side is stopped, or the suction force is controlled to be weak or to maintain the suction force as it is. This makes it possible to reliably move the sheet P.

(Second Embodiment of Sheet Conveying Processing Apparatus)
According to the first embodiment of the sheet transport processing device 5 of the present invention, both the carry-in transport means 57 and the carry-out transport means 58 arranged at the position of the switchback transport path 55 suck and transport the sheet. A sheet conveying means using an air suction method, for example. In contrast,
In the second embodiment, the sheet is similarly suctioned and conveyed only on the side of the carry-in conveyance means 57, that is, the conveyance means is constituted by an air suction system, and the carry-out conveyance means is constituted by a roller method. .

To explain the second embodiment, a description will be given with reference to FIGS. In the second embodiment, the configuration of the carrying-in transport means 57 for carrying the sheet P into the switchback transport path 55 is the same except for the air discharge duct 61 and the discharge port 61a described in the first embodiment. The description is omitted.

Therefore, as shown in FIG. 11, a drive roller 80 which forms a switchback transport path 55 and constitutes an unloading transport means for unloading the sheet P transported into the switchback transport path 55 is provided. Is provided.
The drive roller 80 is arranged with the switchback conveyance path 55 separated from the carry-in conveyance means 57 for carrying the sheet P into the switchback conveyance path 55.

A carry-out driven roller 81 for sandwiching and carrying out the sheet P with the carry-out drive roller 80 is rotatably provided on the carry-in carrying means 57 side.
The driven roller 81 is rotatable at an end opposite to a shaft support portion of a rotation lever 82 rotatably supported at a concave portion provided at, for example, a portion of the suction duct 60 on the side of the carry-in conveyance means 57. Is held. The rotation lever 82 is connected to the suction duct 60.
A gear 82b fixed to one end of the shaft portion 82a is rotatably supported with respect to the shaft portion 82a, and a gear 82b fixed to one end of the shaft portion 82a, as shown in FIG. 83 and is configured so that the rotation lever 82 is rotated.

As a result, the carry-out driven roller 81 rotatably provided on the rotary lever 82 is pressed against the carry-out driving roller 80. In particular, the carry-out driven roller 81 is, as shown in FIG.
It is provided so as to correspond to the portion a. for that reason,
It is provided between the carry-in belts 57c constituting the carry-in carrying means 57. An unloading drive roller 80 is provided so as to correspond to the unloading driven roller 81,
The carry-out driven roller 81 is retracted (submerged) from the conveying surface of the carry-in belt 57c during the carry-in processing of the sheet P.

The unloading drive roller 80 and the driven roller 81 constitute unloading transport means. FIG.
Reference numeral 80a indicated by a broken line in FIG. 2 indicates a rotation drive shaft of the drive roller 80.

The operation, control, and the like of the loading and unloading processing of the sheet P in the sheet transport processing apparatus configured as described above will be described below. The operation and control are shown in FIG.
This will be described with reference to FIG.

First, when the output sheet P on which image formation has been completed is taken in from the main body of the image forming apparatus 1 into the sheet transport processing apparatus 5 via the first transport roller 51, the leading edge of the sheet is detected by the detection sensor 7. You. In response to the detection of the leading edge of the sheet, the suction port 6 of the air suction duct 60 on the side of the carrying-in conveyance means 57 provided in the switchback conveyance path 55.
Air suction is performed from 0a. In addition, the carrying belt 5
The traveling of 7c is also performed. At this time, the unloading driven roller 82
Is in a state of being accommodated in the carry-in transport means 57 side (the state of FIG. 11A).

The sheet P guided to the switchback conveyance path 55 along the switching member 56 is
6a, the carry-in belt 5 of the carry-in carrying means 57
It is guided to the side 7c, and is sucked into the surface of the belt 57c by air suction and carried in (the state from FIG. 11A to FIG. 11B).

After a predetermined time from the time when the trailing edge of the sheet P is detected by the detection sensor 7, the trailing edge of the sheet P is disengaged from the guide piece 56a as shown in FIG. And the loading process is completed. at this point,
Stop the air suction operation. This is as described in FIG. 7 and the like, and the energization to the solenoid 69 constituting the air suction control mechanism is stopped (the state of FIG. 11C).

In this state, the drive motor (not shown) is rotated, and the carry-out driven roller 77 is pressed against the carry-out drive roller 76 via the drive gear 79 as shown in FIG.
To (d). In this rotation state, at least one rotation lever 82 has
b is formed, and a sensor 84 composed of a photo interrupter is provided with the protruding piece 82b interposed therebetween.
In a state where the protruding piece 82b cannot be detected (the optical path is open), the unloading drive roller 80 is pressed against the unloading driven roller 81. Accordingly, in response to the detection result by the sensor 84, the rotation of the drive gear 83 is stopped and maintained at that position. Further, based on the rotation speed (or rotation angle) of the drive motor, control can be performed such that the driven roller 81 is pressed against the drive roller 80.

Then, if the state shown in FIG.
The carried-in sheet P is nipped between the carry-out drive roller 80 and the carry-out driven roller 81, and is carried out by the rotation of the drive roller 80. When the carry-out process proceeds and the discharge process is started by the discharge roller 52 at the front end (the rear end at the time of carry-in) of the conveyed sheet P, the discharge detection sensor 8 detects the start. As a result, the unloading process can be stopped by the unloading drive roller 80 and the driven roller 81 because the unloading process is continuously performed by the discharge roller 52. For this reason, the driven roller 81 is retracted toward the carry-in conveyance means 57 as shown in FIG. 11E by the detected timing signal. In this case, the drive motor (not shown) is rotated in the reverse direction, and the rotation lever 82 is rotated counterclockwise as shown in the figure to retract toward the carry-in conveyance means 57.

In this state, the next sheet P can be carried into the switchback conveyance path 55, and the carrying-in process of the next sheet P is executed as described above. In the switchback conveyance path 55, the sheet P to be carried out and the sheet P to be carried in can be processed so as to overlap. Then, as shown in FIG.
When the loading process is completed and the process is completed, the unloading process of the previous sheet P is also completed, and the process of FIG. Processing can be performed efficiently with the sheet interval shortened.
Note that FIGS. 11B and 11F show the same state in the sheet carry-in processing. Particularly, the state of FIG. 11F shows that the preceding sheet P has completed the reversal processing and is in the discharge processing state. Is shown.

As described above, in the second embodiment, the drive roller 80 and the driven roller 81 that is movably provided and pressed against the drive roller 80 when necessary are provided as unloading / transporting means. As in the case of the first embodiment, in the sheet reversal discharge processing, the sheet interval is shortened, and high-speed operation is enabled. In addition, after being carried in by the carry-in carrying-out means 57, in order to move the sheet P to the discharge carrying-out means side, the carry-out driven roller 81 is pushed out toward the drive roller 80 constituting the carry-out carrying means. Since the sheet P is brought into pressure contact with both of them, the sheet P can be reliably moved to the unloading conveyance means side. This makes it possible to perform the loading and unloading operations accurately and reliably. In addition, the driven roller 81 is not buried in the carrying-in belt 57c of the carrying-in carrying means 57 at the time of carrying-in processing, and is rotatable even if a part thereof is projected. But only rotated.

In the second embodiment described above, by providing the sensor 84 for detecting the position of the movable driven roller 81 provided on the rotation lever 82, the position of the sheet located in the switchback conveyance path 55 is reduced. Presence / absence detection can be performed. That is, in FIG. 11, in the state (d), the rotation lever 82 is rotated and the driven roller 81 is pressed against the drive roller 80, and the optical path of the sensor 84 is not blocked in this state. Therefore, in such a state, it is detected that the sheet P exists in the switchback conveyance path 55 and that the unloading process is performed.

Also, in the sheet P extruding mechanism 76 as shown in FIG. 10, a part 78a of the support member 78 can be used to shield the optical path of the sensor 85 composed of a photo interrupter. It is provided as follows. Accordingly, in a state where the pushing mechanism 76 is retracted toward the carry-in conveyance means 57 with the sheet P carried in, the sensor 85 can detect this state. That is, the retracted state of the pushing mechanism 76 can be detected, and at the same time, the state of the sheet P being carried in the switchback conveyance path can be detected.

For this reason, without providing an actuator or the like for detecting the presence or absence of a sheet in the switchback transport path 55, the sensor 8 can be used to detect whether the sheet is unloaded or loaded.
4 or 85 can be detected. Therefore, it is possible to eliminate the presence of a member that prevents the sheet from being carried in and out of the switchback conveyance path 55.

Although the case in which the sheet transport processing device 5 is provided in the discharge section has been described, the reverse transport processing of the sheet is similarly required in order to read the front and back documents of the sheet document having the image formed on both sides. Becomes The processing apparatus of the present invention can be applied to a portion that performs such a reverse transport process. For example, FIG.
The sheet conveyance processing device 5 described above may be used as it is at the position of the switchback conveyance path 13c of the ADF 13 shown in FIG.

When images are formed on both sides of a sheet,
In the main body of the image forming apparatus 1, after passing through the fixing roller 41, the conveyance path is branched without performing the discharge processing, a switchback conveyance path is provided, and the front and back surfaces of the sheet are reversed and the sheet is conveyed again to the registration roller 38. Is provided. The sheet conveyance processing device of the present invention is provided at the position of the switchback conveyance path in the re-conveyance path, and can be similarly implemented.

[0126]

As described above, according to the sheet transport processing apparatus of the present invention, the sheet can be unloaded while the sheet is being loaded into the switchback transport path. The sheet can be reversed and conveyed in the shortened state. This enables high-speed processing.

Further, in order to carry out the sheet reversing process, the sheet is carried in at least by air suction into the switchback conveyance path, so that the sheet to be carried out and the sheet to be carried in come into contact with each other, It is possible to eliminate dangers such as breakage and bending of the tip, and to make it possible to perform a stable transport process in which a jam or the like is prevented. In this case, the inversion process can be reliably performed regardless of the influence of static electricity or the like.

Further, since a means for surely moving the sheet for which the carry-in processing has been performed to the carry-out / conveying means for performing the reverse conveyance is provided, when the movement processing is completed, the sheet for the next sheet is completed. Since the carrying-in process can be performed, the carrying-in and carrying-out processes can be performed at the same time, and the interval can be made as short as possible. Sheet reversal processing can be performed.

Further, the unloading and conveying means for unloading the sheet is constituted by a drive roller and a driven roller, so that when the sheet is moved to the unloading and conveying means side, the driven roller is moved to the unloading and conveying means side. Since the sheet can be further moved and brought into pressure contact, a means for surely moving the sheet having been conveyed to the unloading side can also be used, and the unloading process can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a side view for explaining a first embodiment of a sheet transport processing apparatus having a sheet reversing function according to the present invention.

FIG. 2 is a perspective view illustrating an appearance of the sheet conveyance processing apparatus illustrated in FIG. 1 in a state where a carry-out conveyance unit side is omitted.

FIG. 3 is a diagram illustrating a state in which a carry-in and carry-out conveyance unit is expanded in a state where a switchback conveyance path is viewed from above in the sheet conveyance processing apparatus illustrated in FIG.

FIG. 4 is an explanatory diagram for explaining an operation of a sheet reversing process in the sheet transport processing apparatus of the present invention.

FIG. 5 is a configuration diagram for describing an internal structure of a digital copying machine including the sheet conveyance processing device of the present invention.

FIG. 6 is a perspective view showing a specific example of an air suction control mechanism in a suction duct for air suction according to the present invention.

FIG. 7 is a diagram for explaining the operation of an on-off valve for opening and closing an air flow passage inside a suction duct of the air suction control mechanism shown in FIG. 6;

FIG. 8 is a diagram showing a configuration of a suction (or discharge) fan constituting a suction unit for air suction according to the present invention.

FIG. 9 is a side view for explaining another embodiment of the sheet discharge processing apparatus according to the first embodiment of the present invention.

FIG. 10 is a view for explaining another embodiment of the sheet transport processing apparatus according to the first embodiment of the present invention, and is an explanatory view for explaining sheet loading and unloading processing operations.

FIG. 11 is a diagram illustrating a configuration of a second embodiment of a sheet transport processing apparatus having a sheet reversing function according to the present invention, and is an explanatory diagram for describing sheet loading and unloading processing operations.

12 is a plan view showing a configuration of a sheet carry-in side as viewed from a sheet carry-out side in the sheet carrying processing apparatus of FIG. 11;

FIG. 13 is a diagram illustrating a configuration of an image forming apparatus including a conventional sheet conveyance processing apparatus having a sheet reversing processing function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Digital copier 10 Scanner part 13 ADF (Automatic original conveyance device) 13a Switchback conveyance path 30 Laser recording part (printer) 5 Sheet conveyance processing device 50 Carry entrance 51 First conveyance roller 52 Ejection path 53 Discharge roller 54 Second conveyance Roller 55 Switchback transport path 56 Switching member 57 Loading transport means 57c Loading belt 58 Loading transport means 58c Loading belt 59 Switchback transport guide 59a Switchback transport guide 60 Air suction duct (loading air suction means) 60a Air Suction port 61 Air discharge duct (air discharge means) 61a Air discharge port 62 Air suction duct (air suction means for unloading) 62a Air suction port 63 Sheet tip regulating plate 65 Open / close valve 69 Solenoid 70 Plunger 72 Fanmo Motor 74 fan 75 fan 76 pushing mechanism 80 out drive roller 81 out follower roller 82 rotating lever

Claims (9)

[Claims] 1. A sheet transport processing apparatus which transports a sheet into a switchback transport path, reverses the feed direction from the switchback transport accounting after transport, and transports the sheet, thereby performing reverse transport of the sheet. A loading / conveying means provided in the switchback transport path and suctioning a sheet fed into the switchback transport path by air to carry the sheet into the switchback transport path; and a switchback disposed opposite to the loading / transporting means. An unloading conveying means for suctioning the sheet conveyed into the conveying path by air and discharging the sheet from the switchback conveying path,
After the sheet is conveyed into the switchback conveyance path, the sheet conveyance includes air suction control means for controlling an air suction state so that the conveyed sheet is adsorbed to the discharge / conveyance means side. Processing equipment. 2. The air suction control means stops the air suction on the carry-in / transport means side and starts the air suction on the carry-out / transport means side when the conveyance of the sheet by the carry-in / conveyance means is completed, or the carry-out / conveyance means The sheet conveying processing apparatus according to claim 2, wherein the air suction force on the side is made larger. 3. A discharge means for discharging air from a carry-in conveyance means to a discharge conveyance means in order to move a sheet conveyed into the switchback conveyance path to a carry-out conveyance means. The sheet conveyance processing device according to claim 1, wherein: 4. A sheet transport processing apparatus which transports a sheet into a switchback transport path, reverses the transport direction from the switchback transport accounting after transport, and transports the sheet, thereby performing reverse transport of the sheet. A loading / conveying means provided in the switchback transport path for adsorbing a sheet fed into the switchback transport path and carrying the sheet into the switchback transport path; and a switchback transport path disposed opposite to the loading / transporting means. And a moving means for moving the sheet carried in by the carry-in / transport means to the carry-out / transport means side. Sheet transport processing device. 5. An extruding mechanism, wherein said moving means is pushed out toward said carry-in / transport means toward a carry-out / transport means side via a switchback conveyance path, and is retracted during carry-in / transport by said carry-in / transport means. The sheet conveyance processing device according to claim 4, wherein the sheet conveyance processing device is provided. 6. The pushing mechanism maintains a state in which the sheet is pushed out to the unloading and conveying means side via the switchback conveying path by the urging means, and is carried in when the sheet is adsorbed and carried in by the carrying in and conveying means. 6. The sheet transport processing apparatus according to claim 5, wherein the sheet is retreated to the carry-in / transporting means side and is pushed out by releasing the suction state of the sheet upon completion of the carry-in. 7. The moving means is provided with a guide member which forms a switchback conveyance path located further downstream of the carry-in / conveyance means and is inclined toward the carry-in / conveyance means. 5. The sheet transport processing apparatus according to claim 4, wherein the sheet is moved toward the unloading and transporting means by a restoring force of the sheet when the suction state is released. 8. A sheet transport processing apparatus which transports a sheet into a switchback transport path, reverses the feed direction from the switchback transport accounting after the transport, and transports the sheet, thereby performing reverse transport of the sheet. A loading / conveying means provided in the switchback transport path for adsorbing a sheet fed to the switchback transport path and carrying the sheet into the switchback transport path; and a switchback transport path disposed opposite to the loading / transporting means. A driving roller for carrying out the sheet carried in from the switchback carrying path, and a sheet separated from the driving roller during carrying-in processing of the sheet by the carrying-in carrying means, and having been carried in by the carrying-in carrying means. And a driven roller for carrying out the unloading process by sandwiching the drive roller with the drive roller. Sheet transport processing device. 9. The driven roller is rotatably provided on a rotation lever rotatably supported on the carry-in / transport means side, and the driven roller is used to move the carried-in sheet to the drive roller side. 9. The sheet transport processing apparatus according to claim 8, wherein the lever is forcibly rotated to be brought into pressure contact with the driving roller.