JP3367843B2 - Refeeding device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention temporarily stores an image-formed sheet and then re-images the image-formed sheet in order to perform image formation again on the back surface or the same surface of the image-formed sheet. It relates to a refeeding device for feeding to a forming position.

[0002]

2. Description of the Related Art When an image forming apparatus completes image formation on one side of a sheet, the sheet is discharged outside the image forming apparatus. Further, there is a case where an image is formed again on the back surface or the same surface of the sheet on which the image formation is completed once. In such a case, the sheet on which the image formation is completed is temporarily stored in the intermediate tray, and the sheet stored in the intermediate tray is re-fed to the image forming position in the next image formation.

In an image forming apparatus, when an image-formed sheet is sent to an intermediate tray, the sheet often curls in either direction. Also, the degree of curl varies in the sheet. Therefore, a sheet jam or the like often occurs when the trailing edge or leading edge of the next sheet is caught at the leading edge or trailing edge of the sheet already stored in the intermediate tray.

As a means for solving the above-mentioned inconvenience, Japanese Patent Publication No. 5-50433 proposes a prevention device thereof. In order to prevent the leading edge of the sheet sent to the intermediate tray from being caught on the trailing edge of the sheet already stored in the intermediate tray, the trailing edge of the accommodated sheet is pressed from above. There is. Then, the sheet front end is pressed down at the timing when the sheet front end reaches the sheet feeding direction front end of the intermediate tray, so that the sheet is favorably fed to the intermediate tray without being caught by the previous sheet storage.

Therefore, as a mechanism for pressing the leading edge and the trailing edge of the sheet from the upper portion of the intermediate tray according to the above Japanese Patent Publication No. 5-50433, the leading edge curl retainer and the trailing edge curl retainer are alternately moved up and down. is doing.

[0006]

In the image forming apparatus, in order to temporarily store an image-formed sheet and to re-feed the accommodated sheet to the image forming position, it is necessary to solve the problem of curling of the sheet. There is a special fair 5-504
In the apparatus disclosed in Japanese Unexamined Patent Publication No. 33, the sheet feeding device for feeding the sheet to the intermediate tray becomes large in size. In particular, before the leading edge of the sheet enters the intermediate tray, this is detected to operate the curl pressing member at the trailing edge of the sheet, and the timing before the leading edge of the sheet enters the leading edge of the intermediate tray in the sheet feeding direction is created. Therefore, it is necessary to push the curl of the tip to operate the member, and a complicated mechanism that is very large in terms of mechanism including control and a control circuit are required. Therefore, the cost of the re-feeding device including the intermediate tray is very high.

Further, the sheet once stored in the intermediate tray may have a problem when it is re-fed as described below due to the curl direction, the curl amount and the like.

For example, as shown in FIG. 8, a sheet P on which an image has been formed is conveyed by a conveying roller 6 provided on a conveying path 60.
1 is fed to the intermediate tray 62 arranged at the lower part. The leading edge of the sheet P has an intermediate tray 6 (not shown).
In the state where the sheet P is in contact with the regulation plate 2, the rear end of the sheet is completely conveyed by the conveying roller 61, and the sheet P is stacked on the intermediate tray 62 by its own weight. At this time, the sheet P
Even if the trailing edge of the sheet P is curled, the pressing member 63 located above the sheet is rotated in the direction of the intermediate tray about the shaft 63a, and the trailing edge of the curled sheet P is moved to the stacking surface of the intermediate tray 61. Hold down.

In the figure, 64 is a paper feed roller for feeding the stacked sheets P from below, and 65 is the sheet fed by the paper feed roller 64 for further feeding to the image forming position. Feeding roller 6 for feeding to the conveying path 67
6 is a separation roller that blocks the feeding of the upper sheet other than the sheet fed by the feeding roller and enables the feeding of one sheet;
Reference numeral 68 denotes an actuator that operates on the sheet P existing on the intermediate tray 62, and the optical sensor 69 constitutes a sheet detecting unit that detects the presence of the sheet.

Therefore, even if the pressing member 63 is pressed, it is necessary to return the pressing member 63 to the upper position (not shown) for receiving the next sheet. At this time, if the sheet is too strong in curl, or if it is stiff, the sheet tries to return to the original curled posture and reaches the position corresponding to the leading edge of the sheet P conveyed through the conveying roller 61. The trailing edge rises, the leading edge of the conveyed sheet P is caught by the trailing edge of the curled sheet, and a jam occurs when the sheet P is fed to the intermediate tray 62.

Further, even if the sheet is pressed by the pressing member 63, the trailing edge of the sheet leans on the inclined guide surface of the sheet as shown in FIG. When the sheet is fed by the operation of the feeding roller 65, a feeding failure occurs.

Further, as the number of sheets P accommodated in the intermediate tray 62 increases, the thickness of the sheets is raised to the bottom, and the rear end of the sheets accommodated in the intermediate tray 62 is inevitably pressed by the pressing member 63. Also, the next sheet P
Will face the position where it is prevented from being fed to the intermediate tray 62, and it becomes necessary to limit the number of sheets to be stored in the intermediate tray 62.

Further, as shown in FIG. 9, a plurality of sheets P
When the sheets are accommodated so as to be stacked on the intermediate tray 62, if the curl amounts of the respective sheets are different, the sheet P1 that is first accommodated in the sheet P that is sent to the intermediate tray 62 is directed toward the sheet regulating member 70. Push it down. As a result, the leading edge of the sheet becomes uneven. Therefore, even at the trailing edge of the sheet, the sheet is displaced from the position of the sheet feeding roller 64 accordingly, and a sheet feeding failure occurs during re-sheet feeding.

In the present invention, in order to solve the above problems, a jam of a sheet sent to an intermediate tray which enables re-feeding of the sheet with a very simple structure, and
An object of the present invention is to provide a re-feeding device that eliminates the occurrence of feeding defects and the like.

In particular, it is an object of the present invention to make sure that the previously accommodated sheet is completely unobtrusive when the next sheet is fed to the intermediate tray regardless of the curl of the sheet, and at the same time, the structure is extremely high. To make it easier.

[0016]

A re-feeding device for achieving the above-mentioned object according to the present invention temporarily stores an image-formed sheet in an intermediate tray, and then stores the accommodated sheet in an image as needed. In the re-feeding device that re-feeds the sheet to the forming position, a carry-in roller that sends in an image-formed sheet for accommodating in the intermediate tray, and one end of the sheet sent in by the carry-in roller are provided in the intermediate tray It corresponds to the pressing member that is pushed down to and one end portion of the sheet that is placed below the carry-in roller and that is accommodated in the intermediate tray. When the pressing member pushes the one end portion of the sheet, the upper end of the one end portion of the sheet is pressed. And an anti-floating member configured to be located at.

In the above-mentioned structure, as shown in FIG. 2, the floating preventing member (31) has a shaft portion (3) as shown in FIG.
2) The seat (P) is swingably provided, and when one end of the seat (P) is pushed down, the seat swings at one end of the seat and returns to the original position shown by the solid line. Is provided with a floating prevention portion (31a) located below the floating prevention member (31). As a result, even if one end of the sheet floats due to curl, it is regulated by the floating prevention portion.
Therefore, there is no possibility that the trailing end of the sheet is fed by the carry-in roller (22) and the leading end of the sheet (P) is caught, and thus the feeding failure does not occur.

Further, in FIG. 2, the floating prevention member (3
1) is a balancer in which the center of gravity is located on the side opposite to the above-mentioned floating prevention portion (31a) in order to return the floating prevention member to the original position (position shown by the solid line) after the pressing action of one end of the seat. And a balancer part (31b).
In b), the floating prevention member (31) is returned to its original position. In such a structure, the structure of the floating prevention member becomes very simple, the one end portion of the sheet can be reliably prevented from floating, and the sheet can be reliably fed to the intermediate tray.

Further, the pressing member (33) has a pressing end (35) for pressing one end of the sheet, and a paper feed for re-feeding the sheet (P) stored on the intermediate tray (21). By providing the pressing roller (36) for pressing the sheet accommodated in the roller (23), the mechanism for pressing the pressing roller (36) to the sheet feeding roller is used as it is to press the one end of the sheet. Can be done at the same time. Therefore, not only is the mechanism very simple, but at the same time as pressing one end of the sheet, the intermediate tray (2
The sheet (P) accommodated in 1) can be reliably fed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a part of a re-feeding device in an intermediate tray for temporarily accommodating a sheet on which an image has been formed according to the present invention. Further, FIG. 2 is an enlarged sectional view showing the details thereof, and FIG. 3 is a plan view thereof. FIG. 4 is a sectional view showing the internal structure of an image forming apparatus equipped with a re-feeding device according to the present invention, particularly a copying machine.

First, the outline of a copying machine which is an image forming apparatus will be described with reference to FIG. In particular, the feeding device of the present invention is not applicable only to a copying machine, and when it is necessary to form an image again on both sides or the same face in a printer or the like, it is needless to say that the feeding device can be directly applied to those feeding devices. .

In FIG. 4, the copying machine is placed on a document table 4 via a photoconductor 1 rotated in the direction of the arrow in the center, a charger 2 for uniformly charging the photoconductor surface, and an optical system 3. A developing device 5 for developing the electrostatic latent image formed after exposing the image of the original document, a transfer device 6 for transferring the toner image formed on the photoconductor to the sheet fed from the sheet feeding device, Further, an image forming unit including a cleaning device (not shown) for removing the toner remaining after the transfer is provided.

The optical system 3 for exposing the image of the original on the photoreceptor 1 is an exposure lamp 3-1 arranged below the original table 4 for illuminating the original, and a mirror for appropriately reflecting the light reflected from the original. The scanning device 3-2, 3-3 and 3-4, the lens 3-5 that forms an image of the reflected light from the document on the surface of the photoconductor 1, and finally the reflected light from the document through the lens. It is composed of a fixed reflection mirror 3-6 which leads to the photoconductor 1. Therefore, the first scanning device including the mirror 3-2 and the exposure lamp 3-1 as the scanning device is mounted on the document table 4
Along with the mirror 3-3 and 3
A second scanning device composed of -4 is run in the same direction at a speed half that of the first scanning device, so that the image of the original is sequentially slit-exposed in accordance with the rotation of the photoconductor 1. Therefore, the image of the original can be formed on the surface of the photoconductor 1.

By exposing the original image by the optical system 3, an electrostatic latent image corresponding to the original image is formed on the surface of the photoconductor 1 uniformly charged by the charger 2. This electrostatic latent image is developed by the next developing device 5, and toner, which is a colorant, is attached to the electrostatic latent image to form a visible image.

The toner image formed on the surface of the photosensitive member 1 is
It is transferred by the action of the transfer device 6 to the sheet P that is appropriately conveyed from the sheet feeding device. The sheet has been conveyed to the position of the registration roller 7 in advance, and is fed to the transfer position (image forming position) facing the transfer device 6 via the registration roller 7 at a timing synchronized with the rotation position of the photoconductor 1. .

The transferred sheet is separated from the surface of the photosensitive member 1 by the action of the separator 8 and is sent to the heat fixing roller 9 along the guide surface. By passing through the heat fixing roller 7, the toner image formed on the sheet is fixed as a permanent image. After that, the paper is discharged onto the discharge tray 10 protruding outside the copying machine.

Next, a sheet feeding device for feeding the sheet to the registration rollers 7 will be described. The sheet feeding device is arranged at the bottom of the main body of the copying machine and can be attached to and detached from the main body (especially, it can be pulled out in the forward direction of the drawing).
The cassette sheet feeding unit 13 is provided with a sheet feeding roller 12 that sends out the sheets P stored in the sheet feeding cassette 11 provided in the above.

Further, the sheet P fed from the sheet feeding device, particularly the cassette feeding section 13, is transferred to the above-mentioned registration roller 7 through various conveying rollers 15 arranged on a conveying path 14 along the arrow direction. Is sent.

On the other hand, the sheet P on which the image formation has been completed as described above is discharged to the discharge tray 10 and is also discharged by the switching gate 16 provided between the fixing roller 9 and the discharge tray 10. The transport direction can be switched. At the switching position, for example, an inversion path 17 for forming an image on both sides of the sheet is provided so as to be branched from the discharge path to the discharge tray 10, and the re-feeding device 2 according to the present invention.
It is sent to 0.

A conveying roller 18 is provided in the reversing path 17 and feeds the re-feeding device 20. Figure 4
As shown in FIG. 3, the sheet P is fed from the cassette sheet feeding unit 13, passes through the conveyance path 14, is temporarily waited at the position of the registration roller 7, and is moved to the transfer position at a timing synchronized with the rotation of the photoconductor 1. Sent. The sheet P separated from the photoconductor 1 by the action of the separator 8 is fixed to the fixing roller 9
It is sequentially discharged to the discharge tray 10 via 2. The path of the sheet P to be fed and conveyed is as shown by the solid line,
The sheets are sequentially stacked on the discharge tray 10.

On the other hand, in order to form an image on both sides of the sheet, the sheet P which has passed the fixing roller 9 has the switching gate 1
At the position of 6, it is sent to the re-feeding device 20 via the reversing path 17. From this re-feeding device 20, the sheet P is fed in the direction opposite to the feeding-in direction, and is fed out to the re-conveying path 19 disposed between the image forming unit and the re-feeding device 20. The re-conveyance path 19 joins the conveyance path 14 that communicates with the registration rollers 7. Therefore, the sheet P fed from the re-feeding device 20 stands by in the registration roller 7 with its front and back surfaces reversed.

(One Form of Refeeding Device) Next, the above-mentioned refeeding device 20 will be described in detail with reference to FIGS. 1 to 3. As shown in FIG. 4, the re-feeding device 20 is provided so as to be interposed between the image forming unit and the cassette paper feeding unit 13.

The re-feeding device 20 is provided with an intermediate tray 21 for sequentially stacking and accommodating the sheets P from the upper part,
Above the intermediate tray 21, there is provided a carry-in roller 22 that communicates with the reversing path 17 on the copying machine main body side and feeds the image-formed sheet to the intermediate tray 21 with its image forming surface facing down. The intermediate tray 21 is arranged horizontally,
A regulating member 21a is provided so as to regulate and align the leading ends of the sheets P when the sheets on which images are formed on the lower surface are sequentially stacked and accommodated. The regulation member 21a
Is provided so as to be movable in the left-right direction in FIG. 1 according to the size of the sheet, and is adjusted and positioned according to the sheet size. Then, the sheet feeding roller 23 that sends out the sheet P stored in the intermediate tray 21 is provided below the portion corresponding to the feeding direction of the intermediate tray 21, that is, the portion corresponding to the trailing end of the sheet fed through the carry-in roller 22. It is provided so that a part thereof projects from the mounting surface of 21.

Further, the feeding roller 24 for feeding the sheet P and the feeding roller 24 for feeding one sheet are arranged so as to face the sheet feeding direction of the sheet feeding roller 23. A separating roller 25 is provided to prevent the feeding of the upper sheet other than the fed sheet. The sheet P fed by the feeding roller 24 is re-conveyance path 19 provided so as to join the conveyance path 14 to the registration roller 7 arranged in front of the image forming position in the copying machine body. It is sent out to the inversion path 26 provided so as to communicate with.

The re-conveyance path 19 is formed so as to be parallel to the surface on which the sheet P of the intermediate tray 21 is placed, and a plurality of sheet conveyance rollers 19a are provided in the middle of the re-conveyance path 19.
・ ・ Is provided. A drive roller 27 for rotating the carry-in roller 22 for carrying in the image-formed sheet P to the intermediate tray 21 as described above is positioned in the communicating portion between the re-conveying path 19 and the reversing path 26. Further, an unloading roller 28 is provided on the surface of the driving roller 27 opposite to the loading roller 22 so as to be brought into pressure contact therewith.

Therefore, the carry-in roller 22 and the carry-out roller 28
Is a driven roller which is pressed against the drive roller 27 and rotates according to the rotation of the drive roller 27. The pressure contact portion between the carry-out roller 22 and the carry-out roller 28 is the reverse path 1
7 and the intermediate tray 21 of the re-feeding device 20.
Is facing. Further, the carry-out roller 28 and the drive roller 27
The pressure contact portion with and is provided so as to face the reversal path 26 and the re-conveyance path 19. Therefore, the intermediate tray 2
A sheet conveying path is provided so that the sheet conveying path to the sheet 1 and the sheet conveying path when the sheet P stored in the intermediate tray 21 is conveyed out are crossed. 22 and unloading roller 2
The pressure contact portions 8 are provided so as to face each other.

The re-conveying path 1 communicating with the reversing path 26.
On the opposite side of the sheet feeding roller 9, the sheet P is fed to the registration roller 7 as described above, and the sheet feeding roller 29 that feeds the sheet is provided at a portion where the sheet P merges with the sheet feeding path 14.

Next, a description will be given of the sheet presser for the sheet P carried into the above-mentioned intermediate tray 21 and the mechanism according to the present invention which prevents the curling of the sheet from disturbing the next sheet.

A paper feed guide 30 having a guide surface for guiding the sheet P carried into the intermediate tray 21 to the above-mentioned pressure contact portion with the carry-in roller 22 and the drive roller 27.
Is provided. This paper feed guide 30 not only has a surface 30a that guides the sheet P into which the sheet P is carried into the intermediate tray 21, but also feeds the leading end of the sheets stored in the intermediate tray 21 in the paper feeding direction to the feeding roller 24. An inclined guide surface 30b inclined so as to guide the sheet, and an inversion guide surface 30c of the inversion path 26 that communicates the sheet with the re-conveyance path 19.
Is equipped with.

When the sheet P is carried into the intermediate tray 21 of the paper feed guide 30, the rear end of the sheet P floats to a higher value than the pressure contact portion between the carry-in roller 22 and the drive roller 27 due to curling or the like. A floating prevention member 31 is provided to prevent this. The prevention member 31 is formed so as to be bent in a dogleg shape, and a shaft portion 32 for allowing the floating prevention member 31 to swing is provided at the bent portion.

The anti-floating member 31 is normally positioned at the position shown by the solid line in FIG. 2, and when the rear end of the sheet is pushed down, it rotates clockwise to the position shown by the broken line in the figure. When the urging state is released, the position returns to the position indicated by the solid line. The floating prevention member 31 is provided in the paper feed guide 3
A shaft portion 32 is rotatably supported at 0.

In the anti-floating member 31 according to the present invention, the one piece facing the rear end of the sheet P which is carried in is the anti-floating section 3
1a, and one piece on the opposite side is the floating prevention member 31.
Is a balancer portion 31b for returning to the original position, that is, the position shown in FIG. Therefore, in the balancer portion 31b, the center of gravity of the floating prevention member 31 is located on the left side in FIG. 2, and the floating prevention member 31 is rotationally biased counterclockwise. Therefore, the balancer 31b comes into contact with the surface of the paper feed guide 30 on the side opposite to the inclined guide surface 30b, so that the paper feed guide 30 is positioned at the position indicated by the solid line.

The paper feed guide 30 further rotatably supports the carry-in roller 22, and the carry-in roller 22 is pressed against the drive roller 29. In particular,
The floating prevention member 31 is provided at a position below the pressure contact portion between the carry-in roller 22 and the drive roller 29. In this example, the shaft portion 32 is provided below the rotation shaft of the carry-in roller 22, that is, on the side of the intermediate tray 21. Therefore, if the trailing edge of the sheet P is located below the flying prevention portion 31a of the flying prevention member 31, the trailing edge of the sheet P is prevented from being positioned higher than the pressure contact portion between the transport roller 22 and the drive roller 27. It

A pressing member for pressing (pushing) the rear end of the sheet P, which is carried into the intermediate tray 21 via the carry-in roller 22, from the upper part toward the intermediate tray 21 side against the floating prevention member 31. 33 is rotatably provided. As shown in FIG. 3, the holding member 33 has support portions 33a at both ends thereof rotatably supported by shafts 34 on both sides of the copying machine body.

A free end portion of the pressing member 33, which faces the leading end side, particularly the carry-in roller 22 side, constitutes a pressing end 35 of the rear end portion of the sheet P, and the pressing end 35 thereof.
Corresponding to, the pressing roller 3 rotatably supported
6 is provided. The pressing roller 36 is pressed against the paper feed roller 23 provided on the intermediate tray 21 side when the pressing member 33 is rotated to the intermediate tray 21 side by being driven by an urging member such as a solenoid (not shown). Is provided. Then, the pressing end 35 can press the rear end of the sheet P toward the intermediate tray 21 side from the upper part by the rotational bias.

The pressing end 35 is set in such a positional relationship that the tip thereof does not come into contact with one end of the floating preventing member 31. Further, as shown in FIG. 3, the pressing end 35 is arranged so as to be narrower than the width direction (width in the direction orthogonal to the conveying direction) of the smallest sheet size to be used, and the floating prevention member 31. Also in, the size is narrower than the minimum size width. That is, the pressing end 35 is provided so that the smallest size sheet P can be pressed, and the floating prevention portion 31 a of the floating prevention member 31 is prevented so that the rear end of the sheet P pressed by the pressing end 35 does not float. Is provided.

In FIG. 3, the anti-floating member 31 is provided on both sides of the center of the sheet to be carried in, but only one may be provided in the center. The same applies to the pressing end 35, and when one floating prevention member 31 is provided, two pressing ends 35 may be provided so as to sandwich both sides thereof. With this configuration, the end portions of the floating prevention portion 31a and the pressing end 35 do not come into contact with each other. Therefore, even if they both project from each other in FIG. The operation of returning to the original state is not hindered. Therefore, it is possible to further extend the pressing end 35 and effectively press the rear end of the sheet P.

In FIG. 1, numeral 37 is a carry-in roller 2.
This is an actuator that operates to detect the sheet guided to 2 and the sheet sent from the reversal path 26 to the re-conveyance path 19, and detects the leading edge of the sheet by the operation of the actuator. 38 is the intermediate tray 2
1 operates on the sheets stacked on the sheet 1, and an actuator 39 for detecting the stacked sheets operates on the sheet conveyed on the re-conveyance path 19, and particularly a sheet before the confluence point to the conveyance path 14 is detected. It is an actuator for detecting.

(Description of Operation of Feeding to Intermediate Tray) Next, an operation of accommodating the sheet P on which an image has been formed into the intermediate tray 21 in the re-feeding device 20 having the above-described configuration will be described.

Sheet P on which an image is formed from the copying machine main body
Is guided by the action of the switching gate 16 to the inversion path 17 when performing double-sided copying. When the sheet P is sent to the reversing path 17, the sheet P is guided to the contact portion between the carry-in roller 22 and the drive roller 27 along the carry-in guide surface 30a of the paper feed guide 30. Then, the driving roller 27 drives the sheet P in a counterclockwise direction to pinch the sheet P between the sheet P and the carry-in roller 22 and send the sheet P to the intermediate tray 21. In this case, the pressing member 33 is arranged at the position shown in FIG. Therefore, the sheet P starts from the leading edge of the intermediate tray 21.
It enters along the upper sheet stacking surface, and the restricting member 21a prevents further carrying-in action.

At this time, the trailing edge of the sheet P is the loading roller 2
The sheet 2 comes out of the contact portion between the driving roller 27 and the driving roller 27, and tries to fall onto the intermediate tray 21 due to its own weight. However, if the curl or the like is strong, the rear end of the sheet P may come to a position higher than the contact portion between the carry-in roller 22 and the drive roller 29. Therefore, when the rear end of the sheet comes out of the action of the carry-in roller 22, the pressing member 33 is urged to rotate counterclockwise in FIG. 1, and the rear end of the sheet P is pressed by the pressing end 35 toward the intermediate tray 21 side. Then, from the state of FIG. 5 (a), the button is pushed as shown in FIG. 5 (b). At this time, the anti-floating member 31 is rotated clockwise at the rear end of the seat, and if the rear end of the seat P passes through that position, its own weight, in particular, the balancer portion 31b acts to restore the original solid line in FIG. Return to position.

Therefore, as shown in FIG. 2, the rear end of the sheet P is positioned below the floating prevention member 31. Therefore, even if the trailing edge of the sheet P is strongly curled, further floating is prevented by the floating prevention portion 31a of the floating prevention member 31, and the intermediate tray 21 passes through the carry-in roller 22 described above.
It does not hinder the sheet P fed into the.

When the rear end of the sheet is positioned below the floating prevention member 31 by the above-described rotation of the pressing member 33, the next sheet P waits for being fed into the intermediate tray 21. The pressing member 33 is released from the biased state and returns to the original position shown in FIG.

By continuing the above operation, the image-formed sheets P are gradually stacked on the intermediate tray 21. At that time, the leading edge of the sheet P is aligned by the regulating member 21a, while the trailing edge of the sheet P is liable to float due to an action force such as curl, but the flying prevention member 33, in particular, the flying prevention portion 3
At 1a, further ascent is prevented. Therefore, the leading edge of the sheet P fed into the intermediate tray 21 will not be obstructed from being conveyed at the trailing edge of the already stored sheet that curls. Moreover, the number of stacked sheets increases and the trailing edge of the sheet P does not float above the position of the solid line of the floating prevention portion 31a of the floating prevention member 33 even when a curling action force is generated.

Therefore, when the sheet is fed again from the intermediate tray 21, the trailing edge of the sheet, that is, in the case of feeding, the sheet P on the leading end side hits the inclined guide surface 31b of the paper feed guide 30, It also eliminates the possibility of defective feeding. Particularly at the time of sheet feeding, as shown in FIG. 5B, the sheet accommodating stack stacked on the intermediate tray 21 is pressed by the pressing member 33.
As shown in FIG.
Is pressed against. Therefore, the curled sheet P is separated from the inclined guide surface 30b and is sequentially fed from the lower part,
Further, it is fed to the registration roller 7 via the paper feeding roller 23 and the feeding roller 24 and the re-transporting path 19 described above.

Here, as shown in FIG. 5 (a), the curl causes the trailing edge of the sheet to be higher than the height H1 which hinders the carry-in operation, while the anti-floating member 31 as in the present invention.
Since the uppermost sheet P is positioned below the floating prevention member 31 by the operation of the pressing member 33, the height H2
It drops below. Therefore, if the leading edge of the sheet P loaded into the intermediate tray 21 is at a height H1 or higher, the operation of loading the sheet is hindered and normal loading cannot be performed.
By reducing the height to less than or equal to H2, the conveyed sheet P can be reliably fed to the intermediate tray 21. Moreover, even if the load of the sheets P increases, the height H
No more than two. This is because the sheet thickness is the above height H
It is a case of 2 or less.

The timing of rotating the pressing member 33 is slightly delayed after the time when the rear end of the sheet P is detected by the actuator 37 arranged between the carry-in rollers 22. As a result, when the trailing edge of the sheet P passes through the carry-in roller 22, the trailing edge of the sheet can be reliably pressed by the pressing edge 35.

Further, in order to feed the sheet P stored in the intermediate tray 21, the pressing roller 36 is provided so as to be movable up and down. However, the mechanism for vertically moving this is used as it is, and the above-mentioned sheet is carried out. The P rear end pressing mechanism is configured. That is, the pressing roller 33 is attached to the pressing member 33.
By providing the pressing roller 3, there is no need to specially provide a mechanism for pressing the rear end of the sheet, and the existing pressing roller 3
A mechanism for pressing 6 to the paper feed roller 23 can be used together, and can also be used as the pressing member 33.

Next, with reference to FIG. 6, a more effective storage configuration of the image-formed sheet P in the intermediate tray 21 and its operation will be described.

For example, half of the maximum number of sheets that can be accommodated in the intermediate tray 21 is accommodated, that is, when the sheets are stacked, the subsequent operation of accommodating the sheets P is ensured. In particular, when the trailing edge of the sheet P curls, the uppermost sheet P may always contact the lower surface of the floating prevention member 33. Therefore, it is conceivable that both sides of the rear end of the sheet P in the width direction warp upward and slightly project upward from the floating prevention member 31. This becomes remarkable as the load capacity increases.

Therefore, when the sheet P stored in the intermediate tray 21 becomes half (N / 2) of the maximum storable amount (N), the pressing member 33 is rotated as shown in FIG. 6 (a). Then, the sheets stored in the intermediate tray 21 are pushed down from above. At this time, the pressing roller 36 is brought into pressure contact with the sheet feeding roller 23, and the stacked sheet P is sandwiched between these rollers. Therefore, the paper feed roller 23 is rotationally driven on the order of several hundred msec. As a result, the entire stacked sheets are sent to the feeding roller 24 side along the inclined guide surface 30b of the paper feed guide 30. Therefore, when the sheet is fed from the trailing end of the sheet, that is, the intermediate tray 21, the leading end of the sheet is separated along the inclined guide surface 30b and moved as shown in FIG. 6B. Therefore, the height is reduced to H3. Therefore, even when the uppermost sheet is bent back on both sides of the trailing edge, the leading edge of the sheet P to be fed next is not caught by the sheet and the feeding is not obstructed.

The timing for driving the paper feed roller 23 is when the maximum storage amount N in the intermediate tray 21 is N / 2, which is carried out by the actuator 37 using a counter. It is performed in the count state of N / 2. Therefore, the paper feed roller 23 may be driven for the above-described time while the press member 33 is rotated and the press roller 36 is in pressure contact with the paper feed roller 23.

Further, in FIG. 7, since the curl amount of the sheets accommodated in the intermediate tray 21 is different, the sheet accommodated first is pushed by the sheet sent in next and is conveyed in. A form will be described in which the leading edge is not aligned and the lowermost sheet is prevented from being out of the sheet feeding operation area of the sheet feeding roller 23.

The sheet P carried in as shown in FIG. 7A acts so as to further push in the sheets P1 and P2 already accommodated in the intermediate tray 21. Therefore, the leading edge of the sheet is regulated by the regulating member 21a, and the lowermost sheet P2 is regulated by the sheet feeding roller 23.
It becomes the last position under the action of. Therefore, as for the regulation member 21a, as shown in FIG. 7B, the regulation position is set in advance from the position of the broken line to the optimum regulation position according to the sheet size to be used. Further, the regulation member 21a may be moved from the position indicated by the broken line to the position indicated by the solid line for each sheet that is carried in, and the sheets P may be aligned and then returned to the position indicated by the broken line.

As a result, it is possible to eliminate the cause of the sheet feeding failure of the lower sheets P1 and P2, and to reliably perform re-feeding.

[0067]

According to the re-feeding apparatus of the present invention, when a sheet on which image formation has been completed is once sent to the intermediate tray, the sheet that has been sent first is not obstructed at all, and the sheet can be reliably fed. Can be sent.

Further, even when the curl is strong,
The sheet does not always reach a predetermined height or more, the next sheet can be reliably fed, and the sheet can be fed without causing a feeding failure even when it is re-fed from the intermediate tray.

In particular, the device according to the present invention can obtain the above-mentioned remarkable effects with a very simple structure without using a special structure for the sheet pressing member.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of a re-feeding device according to the present invention.

FIG. 2 is a partially enlarged portion for accommodating the image-formed sheets in FIG. 1 in an intermediate tray and for re-feeding the accommodated sheets.

FIG. 3 is a plan view of the device of FIG. 2 as viewed from above.

FIG. 4 is a cross-sectional view showing an internal structure of a copying machine which is an example of an image forming apparatus including a re-feeding device according to the present invention.

FIG. 5 is a diagram for explaining the operation of accommodating sheets in the intermediate tray and the operation of re-feeding the accommodated sheets by the re-feeding device of the present invention.

FIG. 6 is a diagram for explaining a form for better performing a sheet accommodating operation according to the present invention.

FIG. 7 is a diagram for explaining another mode for better performing the sheet accommodation operation according to the present invention.

FIG. 8 is a diagram for explaining a problem of the conventional re-feeding device.

FIG. 9 is a diagram for explaining another problem of the conventional re-feeding device.

[Explanation of symbols]

1 photoconductor 5 Development device 6 transfer device 7 Registration roller 14 Transport route 16 switching gate 17 Inversion path 19 Re-transportation route 20 Refeeding device 21 Intermediate tray 22 Carry-in roller 23 Paper feed roller 24 feeding rollers 25 Separation roller 26 Inversion path 27 drive roller 28 unloading roller 30 Paper feed guide 30a inclined guide surface 31 Floating prevention member 31a Floating prevention section 31b Basasa part 32 shaft 33 Holding member 34 rotation axis 35 holding edge 36 Pressing roller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daigo Nishioka 8-22-6 Makuyamadai, Fukuyama City, Hiroshima Prefecture (72) Inventor Tatsuya Senoo 518-6 Ekemachibodo Temple, Fukuyama City, Hiroshima Prefecture (72) Hideaki Sugada 307-3 Hoseiji, Eike-cho, Fukuyama-shi, Hiroshima (56) Reference JP-A-4-55269 (JP, A) JP-A-6-329327 (JP, A) JP-B-5-50433 (JP, B2) ( 58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 83/02 B65H 31/06 B65H 85/00 G03G 15/00 106 G03G 15/00 510

Claims (5)

(57) [Claims] 1. A re-feeding device comprising a feeding roller that temporarily stores an image-formed sheet in an intermediate tray and re-feeds the accommodated sheet to an image forming position, if necessary. A carry-in roller that sends in the image-formed sheet to be stored in the intermediate tray, a pressing member that presses one end of the sheet sent in by the carry-in roller toward the intermediate tray, and a lower part of the carry-in roller. a floating preventing member form so as to be positioned on top of the sheet end portion corresponds to one end of the sheet fed to be accommodated in the intermediate tray, by pressing the sheet end portion by the pressing member is, the floating A sheet stored in the intermediate tray is located below the protection member.
Guide the leading edge of the paper feed direction to the feeding roller.
The inclined guide and the sheet accommodated in the intermediate tray on the side of the feeding roller.
Sheet feeding roller that feeds the sheet to the intermediate tray,
If it becomes half (N / 2) of the amount (N),
Sheets that have been operated and stored are pressed against the paper feed rollers.
The sheets stored by the paper feed roller and the pressing member.
Sheets nipped and rotated by rotating the paper feed roller
The re-feeding device is characterized in that the sheet is fed to the feeding roller side along the paper feed guide . 2. The floating prevention member is swingably provided about a shaft portion, and when one end of the seat is pushed down, the floating prevention member swings at the one end of the seat and returns to the original position. 2. The re-feeding device according to claim 1, further comprising a floating prevention portion, one end of which is located below the floating prevention member. 3. The floatation preventing member includes a balancer portion having a center of gravity on the side opposite to the floatation preventing portion in order to return the floatation preventing member to the original position after the pressing action of the one end portion of the seat. 3. The re-feeding device according to claim 2, wherein the balancer portion is arranged to return the floating prevention member to its original position. Wherein said pressing member, together with the presser edge for pressing the sheet end, according to claim 1, characterized in that a press roller for pressing the sheets stored in the upper Symbol feed roller Refeeding device. 5. A tip of the pressing member is provided to prevent the floating.
It is specially designed so that it does not come into contact with one end of the member.
The re-feeding device according to claim 1, which is used as a characteristic.