JPH06115788A - Paper reversing device - Google Patents

Abstract

PURPOSE:To cope with arbitrary paper from thick paper to thin paper by eliminating problems of paper being reversed and discharged by a reversing roller device, in a reversing device which uses a triroll device and the reversing roller device. CONSTITUTION:A triroll device 5 is disposed at the inlet part of a reversing tray which constitutes a reversing device to perform an action of introducing paper into a reversing tray and reversing and discharging action. Inside the reversing tray, two driving rollers 15, 16 which are driven in an opposite direction to each other are arranged, and one pressure roller 17 is movably mounted relative to the driving roller. While the paper is introduced into the reversing tray, the paper is driven in an insertion direction by a reversing roller device, and after the rear end part of the paper is detected by a sensor S, the pressure roller is pushed against another driving roller to drive the paper in a discharging direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, which uses a reversing device formed by combining a triroll device and a reversing roller device, and inverts and feeds a sheet. 2 for reverse roller device
The present invention relates to a sheet reversing device that uses two driving rollers that are driven in opposite directions and selectively switches a pressing roller that presses a sheet against the driving rollers so that the sheet is conveyed in the reversing tray. .

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a printer, a toner image formed on a photosensitive drum is transferred onto a sheet, the sheet carrying the toner image is fixed through a fixing device, and discharged as a copy. I try to eject it to the tray. In the copy discharged from the device such as the electrophotographic copying machine, the image surface is often upward, and when copying from the first page of the original, the last page is located on the upper side. , It is necessary to change the copy page, and the post-processing is troublesome. Further, in double-sided copying or the like in which images are formed on both front and back sides of a sheet, when a copy made as a single-sided copy sheet in a normal copy mode is accommodated in an intermediate tray, the single-sided copy sheet is guided through a reversing path. A mechanism is provided. Then, the sheet accommodated in the intermediate tray in the inverted state is fed toward the copying of the back side in the same manner as in the case of the sheet feeding tray, and an image is formed on the back side of the sheet.

In the conventional image forming apparatus constructed as described above, an automatic double-sided copying machine is disclosed in, for example, Japanese Patent Laid-Open No.
As shown in Japanese Patent Laid-Open No. 3-196454, a reversing device is arranged in a path for guiding the single-sided copy sheet to the intermediate tray. In the reversing device, the guide path for the sheet is switched between the double-sided copy and the multiplex copy so that the two copy modes can be supported. Further, in the above-mentioned conventional example, a method is used in which one side of a single-sided copy sheet is accommodated in an intermediate tray in a state in which any side of the sheet is faced up. However, in order to simply reverse the sheet, for example, As shown in Japanese Utility Model Laid-Open No. 63-26659, the gate member can be configured as a device that can swing only in one direction.

In addition to the reversing device using the gate and the like of the conventional example, a reversing device using a triroll device is generally known. A reversing device using the triroll device is, for example, as disclosed in Japanese Utility Model Laid-Open No. 2-49953,
A triroll device is arranged at the entrance of the reversing tray, and constitutes a mechanism for reversing and feeding out the paper introduced into the reversing tray. The reversing device using the conventional triroll device is configured as shown in FIG. 5, and the triroll device in which three roller members are combined at the entrance of the reversing tray 2 forming the reversing device 1. 5 is arranged, and a reversing roller device 10 is provided at a predetermined portion of the reversing tray 2. In the triroll device 5, a large-diameter roller in the central portion is used as a driving roller 6, pressure rollers 7 and 8 are arranged on both sides of the driving roller 6, and pressure rollers arranged above and below the driving roller 6 are opposite to each other. It is configured so as to carry the paper in the direction.

The reversing roller device 10 arranged in the middle of the reversing tray 2 is constructed by combining a driving roller 11 and a pressing roller 12, and the driving roller 11 is arranged in the direction of feeding the paper. Driven. Further, the pressing roller 12 pressed by the driving roller 11 constitutes a mechanism for pressing the sheet toward the driving roller by its own weight, and in a state where the sheet is lightly nipped between the two rollers, Adds the action of feeding paper from the reverse tray. In the reversing device 1 configured as described above, the copy paper P is inserted into the reversing tray 2 through the conveyance roller device 3 and between the rollers 6 and 7 of the triroll device 5. At that time, the paper enters between the reversing roller device 10 which is driven in the direction opposite to the insertion direction of the paper, and the roller device gives the conveying action in the returning direction, but the triroll device strongly exerts the conveying action. As a result, the paper is directly inserted inside the reversing tray.

Then, the trailing edge of the paper is the triroll device 5.
After passing through the introducing portion of the sheet, the reversing roller device 10 exerts the returning action, so that the trailing edge of the sheet moves upward along the driving roller 6, and the driving roller 6 and the pressing roller 8
Is nipped between. After that, the reversing roller device 1
0 and the triroller 5 convey the paper in a reversed state, convey it in the paper conveyance path in which the conveyance roller device 4 is arranged, and eject it to the ejection tray, or
It is sent to the output tray. As described above, in the reversing device provided with the triroll device, it is possible to reverse the paper by using a device having a relatively simple mechanism,
The feature that it can be easily applied to an apparatus in which sheets are conveyed at high speed can be exhibited.

[0007]

However, in the conventional reversing device as described above, for example, in the case of a device using a triroll device, the reversing roller device arranged inside the reversing tray ejects the sheet. Always driven in the direction. Therefore, when making a copy using thin paper or the like, if the paper is nipped between the triroll device and the reversing roller device, the paper may buckle. Further, when a relatively thick sheet is used, the reversing roller device exerts a weak conveying action in the reversing direction, which causes a problem that the reversing discharge cannot be properly performed. Therefore, for relatively thick paper, adjustment may be made to increase the pressing force of the pressure roller provided in the reversing roller device, but in that case, there are many obstacles to the reversing action for thin paper. There is a problem that it will occur.

On the other hand, when a reversing device is constructed by combining the gate member and the forward / reverse driving roller device,
Although it is not affected by the thickness of the paper, the strength of the waist, and the like, there is a problem that the control of the constituent members of the reversing device is troublesome. In other words, the detection signal from the sensor is output because it is necessary to switch the gate, switch the forward / reverse drive of the roller, etc. using the information obtained by detecting the trailing edge of the paper in the reversing device. After that, it is necessary to operate a timer or the like and perform control such as switching of each operating member after a certain time has elapsed. In addition, since the operating members are switched as described above, there is a limit to the operating speed of the members forming the reversing device, and there is a problem that it is difficult to easily apply the device to a device having a high sheet conveying speed.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional reversing device, in which two driving rollers having different driving directions are arranged in the reversing tray and the pressing roller is pressed against the driving roller. A mechanism that selectively switches the pressing by the paper is arranged so that the direction in which the paper is conveyed in the reversing tray can be changed, and a device that can reverse and eject at high speed without being affected by the thickness of the paper is provided. The purpose is to do.

[0010]

According to the present invention, a triroll device is arranged at the entrance of a reversing tray, a reversing roller device is arranged at a predetermined position of the reversing tray, and a sheet introduced into the reversing tray is reversed. The present invention relates to a reversing device that sends out in a state where it is allowed to move. In the present invention, the reversing roller device disposed inside the reversing tray is configured by combining two driving rollers having different rotation directions and a pressing roller selectively contacting the driving roller. A detection unit for detecting the trailing edge of the sheet is disposed upstream of the triroll device disposed in the above-described configuration, and a combination of a driving roller and a pressing roller is used for the sheet inserted into the reversal tray via the triroll device. Is selectively switched to move the paper in the forward and reverse directions.
Further, in the reversing device of the present invention, in order to change the pressing position by the pressing roller, a pressing device in which a pressing roller is provided on the disk member is used, and the disk member is rotated to drive the pressing roller in contact. Means for switching the rollers can be used.

As described above, in the present invention, since the reversing roller device arranged inside the reversing tray uses the two driving rollers which are driven in the opposite directions, the operation of inserting the paper into the reversing tray, Since the operation of ejecting the paper is performed by another roller device, the thickness of the paper, the strength of the waist, and the like are not affected. Further, since the operation of switching the sheet conveying direction by the reversing roller device can be performed at high speed, the reversing device of the present invention can be easily used even in an electrophotographic copying machine or the like having a high sheet conveying speed. is there. By using the swing arm and the rotating member for switching the sheet conveying direction in the reversing roller device, the operating member can be easily controlled without complicating the mechanism of the reversing device. be able to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The sheet reversing device of the present invention will be described with reference to the examples shown in the drawings. In the example shown in FIG. 1, as in the case of the conventional reversing device, the triroll device 5 is arranged at the entrance of the reversing tray 2, and the triroll device 5 passes between the drive roller 6 and the pressing roller 7. , Paper reversal tray 2
Inserted in. Further, the sheet discharged from the reversing tray passes between the driving roller 6 and the pressing roller 8 of the triroll device 5 and is reversed and discharged toward the next processing step. In the reversing tray 2 in which the triroll device 5 is arranged at the entrance, instead of the conventional reversing roller device, two driving rollers 15 and 16 are arranged at the bottom,
The two driving rollers are rotated in opposite directions.

Further, one pressing roller 17 is arranged in correspondence with the two driving rollers, and the pressing roller 17 is provided.
Is supported by a swing arm 18, and the arm 18 is swung by a solenoid 19 via a fulcrum 18a.
Can be selectively positioned with respect to the two drive rollers. The pressing roller supported by the arm member 18 is supported via a long hole or the like provided in the arm, and is provided in a freely rotatable state. Then, when the sheet is pressed against the drive roller, a pressing force is exerted by the weight of the roller member itself, and even if there is a difference between the conveyance speed of the roller device of the triroll device and the conveyance speed of the reversing roller device. , The triroller is configured so that it does not hinder the paper feeding operation.

In the reversing device 1 of the present invention configured as described above, the sensor S for detecting the trailing edge of the sheet is arranged at a predetermined position of the introduction path to the reversing tray 2, and the sensor S is provided. The control device is configured to drive the solenoid in response to the detection signal from. Further, of the two drive rollers arranged on the reversing tray 2, the roller 15 is driven in the direction for accommodating the paper and the other roller 16 is driven.
Drives in the direction to eject the paper. When the sheet is inserted into the reversing tray 2, the pressing roller 17 is driven by the drive roller 15 as shown by the solid line in the figure.
The sheet is conveyed to the right side of the drawing while being disposed at a position corresponding to the sheet, while nipping the sheet between the rollers 15 and 17.

Then, when a predetermined time elapses after the rear edge of the sheet is detected by the sensor S, the solenoid 1
A drive signal for 9 is output to swing the arm 18 to swing the pressing roller 17 to a position corresponding to the driving roller 16. When the operation of the solenoid is performed,
The trailing edge of the sheet is in a state where it has finished passing through the introduction portion of the triroll device, and the sheet is driven toward the discharge side by reversing the driving direction of the reversing roller device 14 with respect to the sheet. . As described above, when the action of feeding the sheet is given, the trailing end of the sheet becomes the leading end of the feeding side, but the leading end of the feeding side of the sheet is pressed against the peripheral surface of the drive roller 6. In this state, it moves upward along the roller 6 and is inserted into the nip portion between the rollers 6 and 8. Then, the sheet is reversed and discharged toward the next step through the discharge side rollers of the triroll device, and the pressing roller 17 is returned to the original position and waits for the next sheet inverting operation. To do.

In the reversing device shown in FIG. 1, the two drive rollers arranged in the reversing tray 2 are constantly driven while the electrophotographic copying machine is set to the mode for reversing and ejecting the paper. Can be configured as one. Further, as the switching mechanism for pressing the pressing roller against the driving roller, any other arm driving means can be used. Then, in the reversing device of the embodiment shown in FIG. 1 of the present invention and another embodiment described later, as in the case of the conventional reversing device, a reverse discharge and a guide mechanism capable of direct discharge are provided in the paper transport path. For that purpose, the positional relationship between the arbitrary branch guide mechanism and the sheet conveying path can be arbitrarily set.

(Other Embodiment of Pressing Device) As described above, instead of using the arm member to press the pressing roller against the driving roller of the reversing roller device, in the present invention, FIG. It is also possible to use the pressing device 20 as shown in FIG. The pressing device 20 shown in FIG.
In order to press the paper against the two drive rollers 15 and 16, a disk-shaped support member provided with two pressing rollers 25 and 26 is used. The drive roller for pressing the paper can be switched by rotating 22.
In the pressing device 20, the disk members 21 and 22 are fixedly held in a skewered shape with respect to the drive shaft 23, and the drive shaft 2
3 is provided with a motor 24.

The disc members 21 and 22 support the pressing rollers 25 and 26 through the two long holes 29 and 29a, and the shafts 27 and 28 of the pressing rollers are provided on the disc members. It is movably installed along the long hole. Therefore, when the pressing roller presses against the driving roller, the nip pressure can be set by the weight of the pressing roller, and the sheet conveying operation in the reversing roller apparatus can be set against the sheet conveying operation in the triroll apparatus. Will not be affected.

In the reversing tray using the pressing device shown in FIG. 2, the reversing roller device 14 can be constructed by combining with two driving rollers as shown in FIG. In the reversing device shown in FIG. 3, when the sheet is inserted into the reversing tray via the triroll device 5, the pressing roller 25 of the pressing device 20 is moved to the driving roller 15 as shown by the solid line in the figure. The sheets are set at the corresponding positions and serve to guide the sheet into the inside of the reversing tray 2. Then, when the rear end of the sheet is detected by the sensor S provided in the introduction path and a predetermined time has elapsed, the disc member 21 is rotated counterclockwise so that the pressing roller 25 is indicated by the chain line. , To a position corresponding to the drive roller 16.

As described above, the pressing roller 25 is moved to a position corresponding to the driving roller 16, and immediately after the trailing edge of the sheet has finished passing through the introduction portion of the triroller, the reversing roller unit 14 is operated. A state in which the action of driving in the returning direction is given is set. Then, the leading end of the sheet on the discharge side is guided upward along the drive roller 6, and the sheet is inserted between the drive roller 6 and the pressing roller 8, whereby the roller device of the triroll device 5
Perform the operation to eject the paper. Further, in the apparatus of the present invention, in order to switch the position where the pressing roller is pressed between the two driving rollers, the disk member is only slightly rotated, so that the roller device does not move in the sheet conveying direction. The switching operation time will be very short.

As described above, when the mechanism for changing the position of the drive roller for pressing the pressing roller by rotating the disk member is constructed, the paper discharged from the reversing tray is the discharging portion of the triroll device. When it is nipped in, the feeding operation by the reversing roller device 14 is not required. Therefore, in the present invention, as shown in FIG. 4, while the paper is being sent out from the reversing tray, the disk member is driven counterclockwise and immediately after the paper P is discharged from the reversing tray. The pressing roller 26 is set at a position corresponding to the driving roller 15. Then, when the next sheet is introduced into the reversing tray, the reversing roller device can immediately pull in the sheet.

In the reversing device of the present invention configured as described above, the pressing device 20 can be configured as a mechanism for rotating the pressing device 20 at an arbitrary speed in accordance with the paper conveyance speed in the image forming apparatus. In addition, even if a state in which the next sheet is introduced into the reverse tray occurs while the sheet is being discharged from the reverse tray, as shown in FIG.
In the reversing roller device, the pressing roller is not in a state of being pressed against the driving roller, so that it is possible to allow two sheets of paper to move in opposite directions in the reversing tray. And
Looking at the timing at which the preceding paper is sent out from the reversing tray, the pressing roller is pressed against the driving roller 15 to cause the paper to be introduced into the reversing tray, and the detection signal at the rear end of the paper causes The pressing roller is pressed against the driving roller 16 so that the paper can be ejected.

Therefore, as described above, while moving the two pressing rollers in accordance with the rotation of the disc member,
By pressing the paper against the two drive rollers and switching the carrying direction with respect to the paper, it is possible to prevent the paper being moved in the reversing tray from having an extra carrying action. Even if the paper to be flipped is thin and weak, or paper with different properties from plain paper, such as thick paper, it is possible to reasonably perform the reversing action using the reversing device. To Further, in the reversing device of the present invention, the two driving rollers of the reversing roller device can be composed of rubber rollers, and the pressing roller can be composed of a material having a relatively small friction coefficient such as plastic. It can be configured as a device that does not exert the paper transporting action of.

[0024]

As described above, the reversing device of the present invention has the following features.
In the present invention, since the reversing roller device arranged inside the reversing tray uses the two driving rollers which are driven in the opposite directions, the operation of inserting the paper into the reversing tray and the operation of discharging the paper are Since it is performed by another roller device, the thickness of the paper, the strength of the waist, and the like are not affected. Further, since the operation of switching the sheet conveying direction by the reversing roller device can be performed at high speed, the reversing device of the present invention can be easily used even in an electrophotographic copying machine or the like having a high sheet conveying speed. is there. By using the swing arm and the rotating member for switching the sheet conveying direction in the reversing roller device, the operating member can be easily controlled without complicating the mechanism of the reversing device. be able to. Further, in the reversing roller device of the present invention, the operation of switching the conveying direction for the paper can be performed in a short time, so that an extra action is not given to the paper to be reversed and the thin paper to the thick paper is not applied. It is possible to apply a reversal action to any paper up to.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a reversing device of the present invention.

FIG. 2 is a perspective view of a pressing device used in another embodiment of the present invention.

3 is a side view of a reversing device using the pressing device of FIG.

FIG. 4 is an explanatory diagram of a state in which the disc member is being rotated.

FIG. 5 is a side view showing the configuration of a conventional reversing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 reversing device, 2 reversing tray, 5 triroll device, 6 driving roller, 10 reversing roller device, 11 driving roller, 12 pressing roller, 1
5.16 drive roller, 17 pressure roller, 18
Arm member, 20 pressing device, 21/22
Disc member, 25/26 pressure roller, 29/29
a long hole.

Claims (2)

[Claims] 1. A reversing tray in which a triroll device is arranged at the inlet of a reversing tray, a reversing roller device is arranged at a predetermined position of the reversing tray, and a sheet introduced into the reversing tray is fed out in a reversed state. The reversing roller device arranged inside the reversing tray is configured by combining two driving rollers having different rotation directions and a pressing roller selectively contacting the driving roller, and is arranged in the reversing tray at an upstream portion of the triroller device. To
A detection means for detecting the trailing edge of the paper is arranged, and the combination of the drive roller and the pressure roller is selectively switched for the paper to be inserted into the reversing tray through the triroll device, and the paper is reversed. A sheet reversing device, characterized by performing an operation of moving the sheet in a direction. 2. A pressure device in which a pressure roller is provided on a disk member is used to change the pressure position by the pressure roller, and the drive roller in contact with the pressure roller is switched by rotating the disk member. Claim 1 characterized by the above-mentioned.
The paper reversing device described in 1.