JP2000016661A - Paper inversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper inversion device capable of being manufactured comparatively inexpensively and stably inverting a surface and a rear surface of a paper fed into without performing extra control. SOLUTION: A conveyance roller 21 and a conveyance auxiliary roller 22 are arranged by differing their positions in the assembly and deviating rollers 31 and 32 in the axial direction mutually. An inversion roller 23 is provided so as to follow the conveyance roller 21 and rotate, and the inversion roller 23 and an inversion auxiliary roller 24 are arranged by differing their positions in the assembly by deviating rollers 33 and 34 in the axial direction mutually. Furthermore, a pair of guide members 28, 28 pressing the paper conveyed onto the inversion roller 23 against the inversion roller 23 are provided. Consequently, the paper is pressurized on the inversion roller 23 by the guide members 28, and the direction of advance is changed by a conveyance force by the inversion roller 23 to convey the paper securely by a simple configuration in which the inversion roller 23 is merely rotated in one direction at all times continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet reversing device for reversing a fed sheet.

[0002]

2. Description of the Related Art Conventionally, as a sheet reversing apparatus for reversing a sheet fed as described above, a sheet reversing apparatus is generally used by switching a transport path of the sheet fed. An example will be described. A switching claw whose position can be switched by a solenoid or the like is provided at a switching portion of the transport path, and a pair of rollers (rollers) are provided on the downstream side in the direction in which the sheet is fed to the switching claw. Good)
In some cases, the pair of rollers can be selectively rotated in both forward and reverse directions by a motor.

In this paper reversing device, after the trailing end of the fed paper passes through the switching claw, the switching claw is rotated to switch the conveyance path, and further, the motor is rotated in reverse to rotate the pair of rollers in reverse. Then, the paper passing through the switching claw is changed in traveling direction with the rear end side as the front end side, and is transported to the switched transport path to reverse the front and back sides.

[0004]

However, the switching section of the transport path is provided with a switching claw rotated by a solenoid, and a pair of rollers located on the downstream side in the direction in which the sheet is fed to the switching claw. In the case of a paper reversing device in which the rotation direction of the motor is changed by a motor, the cost tends to be high, and control for changing the rotation direction of the motor at a predetermined timing is required, which complicates the control. There was a problem that would.

There is also a paper reversing device in which the paper transport path is switched by a pair of rollers. In this device, the driving speed of the transport system is changed, or control not required for the original paper transport is performed. However, there is a problem such as the necessity of doing so, so that such a thing is not actually put into practical use at present.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and can stably turn a sheet fed without any extra control while being able to be manufactured relatively inexpensively. It is an object of the present invention to provide a sheet reversing device capable of performing the above-described operations.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a transport roller in which a plurality of rollers are arranged at intervals in the axial direction, and a transport auxiliary roller paired with the transport roller. A transport roller unit in which the positions of the above-mentioned rollers are shifted in the axial direction with respect to each other so that the rollers on the transport roller side and the rollers on the auxiliary transport roller side do not come in contact with each other, and the paper when the paper is received by the transport roller unit A reversing roller provided downstream of the conveying direction and driven to rotate by the conveying roller, and a reversing roller portion including a reversing auxiliary roller paired with the reversing roller, and disposed near the reversing roller; A sheet reversing device is provided by providing a guide member that presses the sheet conveyed on the reversing roller against the reversing roller and applies a rotating force of the reversing roller to the sheet.

[0008] Further, the strength of the paper roll squeezed by the plurality of rollers, which is arranged in the combination of the transport roller and the transport auxiliary roller, is smaller than the strength of the stiffener squeezed by the reversing roller portion. It is effective to be strong. Further, the guide member includes an entrance member disposed on the entrance side of the sheet to the guide member and an exit member disposed on the exit side, and the entrance member and the exit member are respectively It is preferable that the end portions on the side opposite to the side supported by the support shaft are rotatably attached to the support shaft and are biased by a spring in a direction approaching the reversing roller.

Further, it is effective to arrange a pair of the guide members at positions respectively corresponding to both ends of the transport roller. The pair of guide members may be rotatably mounted on shafts that support the reversing auxiliary roller.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a sheet reversing mechanism of a sheet reversing device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing a guide member of the sheet reversing device, and FIG. FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus equipped with the sheet reversing device.

In the image forming apparatus shown in FIG. 3, a sheet reversing device 2 is mounted above a side portion of an apparatus main body 1, and a four-stage paper feed cassette 3 is provided at the bottom of the apparatus main body 1. . A conveying path extending upward is formed on the upper right side of the apparatus main body 1 in FIG. 3, and registration rollers 4, an image forming section 5, and a fixing section 6 are provided on the conveying path in order from the upstream side in the sheet conveying direction. ing. The image forming unit 5 includes a photosensitive drum 12 that rotates in a direction indicated by an arrow A and various electrophotographic processing units provided around the photosensitive drum 12. An image is formed by the method.

A switching claw 7 is provided on the downstream side of the fixing unit 6 in the sheet conveyance direction. By switching the rotation position of the switching claw 7, the sheet P passing through the fixing unit 6 is connected to the sheet discharge path 8 and It can be selectively conveyed to the reversing passage 9. A paper discharge roller 10 is provided downstream of the paper discharge path 8, and the paper P conveyed to the paper discharge path 8 by the paper discharge roller 10 is discharged onto a paper discharge tray 11.

The reversing path 9 is a path facing the sheet receiving port 13 of the sheet reversing device 2, and the sheet P guided to the reversing path 9 is fed into the sheet reversing device 2. The sheet reversing device 2 functions to reverse the sheet P sent from the apparatus main body 1 upside down and discharge the sheet P to the apparatus main body 1 again through the discharge port 14.

In the sheet reversing device 2, a sheet reversing mechanism 20 (to be described in detail later) as shown in FIG.
In FIG. 3, an evacuation path 26 is provided once on the right side, and a delivery conveyance path 27 is provided below, and a delivery roller 25 is provided at an exit portion of the delivery conveyance path 27. When the sheet P is fed into the sheet reversing device 2 from the sheet receiving port 13, the leading end of the sheet P is once conveyed to the evacuation path 26. Then, when the rear end of the sheet P reaches the sheet reversing mechanism section 20, the traveling direction of the sheet P is changed with the rear end side as the front end side, and the sheet P is conveyed to the delivery conveyance path 27 this time.

Then, the paper P is fed to the delivery roller 2
The paper 5 is sent out of the apparatus main body 1 from the discharge port 14 by the registration roller 4, the timing is adjusted by the registration roller 4, and the paper is again conveyed to the image forming unit 5. Then, since the sheet P is turned upside down, an image is formed on the back side where no image is formed this time. After the image (toner image) is fixed by the fixing unit 6, the sheet P is guided by the switching claw 7 rotating counterclockwise in FIG. The paper is discharged onto the paper discharge tray 11 by the rollers 10.

As shown in FIG. 1, the paper reversing mechanism 20 includes a transport roller 21 having a plurality of rollers 31 disposed at intervals in the axial direction, and a plurality of rollers 32 similarly disposed at intervals in the axial direction. The rollers 31 and 32 are arranged in the axial direction so that the rollers 31 and 32 on the side of the transport roller 21 and the rollers 32 on the side of the transport auxiliary roller 22 are shifted from each other. It has a transport roller unit 15 arranged in a wrong combination so as not to contact.

The paper reversing mechanism 20 is provided downstream (rightward in FIG. 1) in the paper transport direction when the paper is received by the transport roller 15 and is driven by a transport roller 21 to rotate. , A reversing roller section 16 composed of the reversing roller 23 and a pair of reversing auxiliary rollers 24. Further, the sheet reversing mechanism section 20 is disposed close to the reversing roller 23, and presses the sheet conveyed on the reversing roller 23 against the reversing roller 23 to apply the rotating force of the reversing roller 23 to the sheet. It also has a pair of guide members 28,28.

As shown in FIG. 4, the transport rollers 21 and the transport auxiliary rollers 22 have rollers 31 and 32 wrapped by a predetermined amount when viewed from the side, and the rollers 31 and 32 are connected to each other as described above. Since they are offset from each other in the axial direction, they are in non-contact with each other. However, since the rollers 31 and 32 are in a wrapped state, when the paper P is fed between the transport roller 21 and the transport auxiliary roller 22 as shown in the drawing, the paper is wavy by the rollers 31 and 32. It is moderately strained. As a result, the paper P comes into contact with the transport roller 21 with an appropriate contact pressure, and
The transfer force from works.

Similarly, in the reversing roller 23 and the reversing auxiliary roller 24, the rollers 33 and 34 overlap each other by a predetermined amount when viewed from the side surface. (See FIG. 1) Since the roller 34 on the side of the reversing auxiliary roller 24 is displaced from the roller 34 in the axial direction,
They are in non-contact with each other.

However, since the rollers 33 and 34 are in a wrapped state, when the sheet P is fed between the reversing roller 23 and the reversing auxiliary roller 24, the sheet P is curved by the rollers 33 and 34. A weak strain is made. In the sheet reversing device 2, the plurality of rollers 31 and 32, which are arranged in a mutually different manner of the transport roller 21 and the transport auxiliary roller 22 as described above, are used to stiffen the paper by the plurality of rollers 31 and 32. The lap depth and the axis of the rollers 31 and 32 are set so that the strain is stronger than the strength of the strainer rubbed by the roller 33 on the reversing roller 23 side and the roller 34 on the reversing auxiliary roller 24 side of the reversing roller section 16. The spacing between the directions is set.

In the reversing roller 23, a plurality of rollers 31 formed at both ends in the axial direction are formed at intervals along the axial direction of the transport roller 21. Are in contact with the respective rollers 31 near both ends, and are rotated by the rotation of the transport roller 21.

The guide member 28 includes an entrance member 29 disposed on the entrance side (left side in FIG. 4) of the sheet into the guide member 28 and an exit member 30 (see FIG. 4) disposed on the exit side. 2), the entry side member 29 and the exit side member 3
As shown in FIG. 1, reference numerals 0 are rotatably attached to both ends of a shaft 35 that supports the reversing auxiliary roller 24 that is a support shaft. Therefore, the pair of guide members 2
8 and 28 are kept parallel to the reversing roller 23.

The entry side member 29 and the exit side member 30 are arranged such that the end opposite to the side supported by the shaft 35 (FIG. 1) by the spring 36 shown in FIG. Each is urged to rotate. In addition, as is clear from FIG.
It is disposed at a position corresponding to each of both ends of the transport roller 21.

Next, the operation of the sheet reversing mechanism 20 will be described with reference to FIGS. As shown in FIG. 4, the paper P is pressed against the transport roller 21 rotating in the direction of arrow B by the transport auxiliary roller 22, and is transported rightward in FIG. 4 by the transport force of the transport roller 21. As shown, when the sheet P reaches the entry side member 29 of the guide member 28, the paper P is transferred to a plurality of rollers 31,
Since the corrugated state is applied by 32 and a moderate stiffening is performed, the approach-side member 29 of the guide member 28 is pushed up and is rotated upward with the shaft 35 as a fulcrum.

At this time, the roller 33 of the reversing roller 23 is in contact with the roller 31 of the conveying roller 21 rotating in the direction of arrow B, and it is rotated (followed) in the direction of arrow C. However, as described above, since the reversing auxiliary roller 24 does not contact the reversing roller 23 (the roller 33
The paper P conveyed between the reversing roller 23 and the reversing auxiliary roller 24 is displaced in the axial direction only while the reversing roller 23 partially contacts the lower surface thereof. 4 is conveyed rightward in FIG. 4 by the conveyance force between the conveyance roller 21 and the conveyance auxiliary roller 22.

In the case of a non-thick sheet of normal paper thickness, when the entry member 29 is pushed up as described above, the guide member 28 is moved by the exit member 30 by that much.
Is pushed down with the shaft 35 as a fulcrum. Further, as described above, the strength of squeezing the paper by the transport roller 21 and the auxiliary transport roller 22 is set to be stronger than the strength of stiffening of the paper by the reverse roller 23 and the reverse auxiliary roller 24. Therefore, even when the sheet is conveyed between the reversing roller 23 and the reversing auxiliary roller 24, the sheet does not break during the conveyance.

Then, as shown in FIG. 5, the leading end of the sheet P reaches the position of the exit side member 30, and the exit side member 30
When the paper P is moved while being guided along the lower surface of the paper P, the paper P is moderately rubbed by the rollers 31 of the transport rollers 21 and the rollers 32 of the transport auxiliary rollers 22 as described above. The sheet P rotates in a direction in which the outlet side member 30 is pushed up.

As a result, the guide member 28 rotates in the counterclockwise direction in FIG. 5, so that the left approach side member 29 in FIG. Therefore, the sheet P conveyed between the reversing roller 23 and the reversing auxiliary roller 24 is pressed against the reversing roller 23 by pushing down the entry side member 29, and the conveying force from the reversing roller 23 in the direction of arrow C is applied. , But the conveyance is continued in the direction of the arrow E in that state.

When the sheet P is conveyed to a position where the trailing end is separated from the conveying roller 21 and the auxiliary conveying roller 22, the conveying force in the direction indicated by the arrow E is no longer received from these rollers. Due to the conveyance force of the reversing roller 23 rotating in the direction indicated by the arrow C, the switchback conveyance is performed in the reverse direction. Therefore, the paper P
The rear end is forwarded by switchback, is fed between the conveying roller 21 and the reversing roller 23, and is conveyed to the feeding conveying path 27.

At the time of the switchback, the sheet P is pushed down by the entry side member 29 of the guide member 28 and strongly receives the conveying force in the direction of arrow C from the reversing roller 23, so that the sheet P is switched back and the traveling direction is changed. Then, a stable reversing operation is performed without delaying the conveyance.

On the other hand, when the paper is thick,
Since the paper itself is originally strong, the entry-side member 29 is pushed upward to rotate clockwise in FIG. 5 around the shaft 35 as a fulcrum.
The entry-side member 29 is independently rotated around the shaft 35 as a fulcrum in the clockwise direction against the urging force of the spring 36 shown in FIG. Therefore, even when thick paper is conveyed, it is possible to prevent an increase in load during conveyance. It should be noted that the guide member 28 is also provided when the leading end of the thick paper reaches the exit side member 30.
The outlet member 30 is driven by the shaft 3 against the urging force of the spring 36.
5 rotates counterclockwise in FIG.

[0032]

As described above, the sheet reversing device according to the present invention has the following effects. According to the paper reversing device of the first aspect, it is possible to use a simple configuration that always rotates the reversing roller in one direction without using an expensive solenoid or requiring complicated control. Can be manufactured. Further, since the guide member presses the paper whose traveling direction is changed by the reversing roller and ensures the conveyance by the reversing roller, it is possible to prevent a delay in reversing the paper whose traveling direction is changed.

According to the sheet reversing device of the second aspect, the sheet to be reversed is conveyed after being appropriately stiffened by the conveying roller section and the reversing roller section, so that the sheet is not broken during the conveying process. You can do so. According to the sheet reversing device of the third aspect, since the guide member has the entry side member and the exit side member rotatably attached to the support shaft, when the paper is thick paper, the entry side member and the exit side are used. Since the members rotate independently, it is possible to prevent an increase in load and to perform stable conveyance.

According to the sheet reversing device of the fourth aspect, both sides of the sheet to be reversed can be reliably brought into contact with the reversing roller by the pair of guide members, so that the sheet can be stably reversed and transported. it can. According to the paper reversing device of the fifth aspect, since the fulcrum of the pair of guide members is coaxial with the axis supporting the reversing auxiliary roller, the pair of guide members can easily maintain the parallelism with the reversing roller. Since both sides of the paper can be reliably brought into contact with the reversing roller,
Skew is less likely to occur during reverse transport of paper.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a sheet reversing mechanism of a sheet reversing device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a guide member of the sheet reversing device.

FIG. 3 is a schematic diagram illustrating an example of an image forming apparatus to which the sheet reversing device is mounted.

FIG. 4 is a side view showing a state in which the leading end of the sheet reaches the position of the entry side member 29 of the guide member 28 and pushes up the entry side member 29 in the sheet reversing mechanism of FIG.

FIG. 5 is a side view showing a state in which the leading edge of the sheet reaches the position of the exit side member 30 of the guide member 28 and the entrance side member 29 is pushed down by pushing up the exit side member 30 in the sheet reversing mechanism. It is.

[Explanation of symbols]

 21: Conveying roller 22: Conveying auxiliary roller 23: Reversing roller 24: Reversing auxiliary roller 28: Guide member 29: Entry side member 30: Outlet side member 31, 32, 33, 34: Roller 35: Shaft (support shaft) 36: spring

Claims (5)

[Claims] 1. A transport roller in which a plurality of rollers are disposed at intervals in an axial direction and a transport auxiliary roller which forms a pair with the transport roller is displaced in the axial direction with respect to each roller. And a transport roller unit that is mis-assembled so that the roller on the side of the transport auxiliary roller does not come into contact with the roller on the side of the transport auxiliary roller. A reversing roller section comprising a reversing roller to be rotated and a reversing auxiliary roller forming a pair with the reversing roller; a reversing roller disposed in close proximity to the reversing roller; A sheet reversing device provided with a guide member that presses the sheet to apply the rotational force of the reversing roller to the sheet. 2. The method according to claim 1, wherein the plurality of rollers, which are provided in the transport roller and the auxiliary transport roller, are arranged in a mutually different manner. 2. The sheet reversing device according to claim 1, wherein said sheet reversing device is stronger than said sheet reversing device. 3. The guide member comprises an entry member disposed on the entry side of the sheet to the guide member, and an exit member disposed on the exit side. The members are rotatably attached to the support shafts, and the ends opposite to the sides supported by the support shafts are biased by a spring in a direction approaching the reversing roller. The sheet reversing device according to claim 1. 4. The sheet reversing device according to claim 1, wherein a pair of the guide members are provided at positions respectively corresponding to both ends of the transport roller. 5. The sheet reversing device according to claim 4, wherein the pair of guide members are rotatably attached to shafts supporting the reversing auxiliary rollers.