JPH06236086A - Paper reversing device for image forming device - Google Patents

Abstract

PURPOSE:To perform the switching operation of driving a reversing roller device through a clutch mechanism in the case of branching a one-sided copying paper to an intermediate tray in an automatic double-sided copying machine. CONSTITUTION:In the reversing roller device 25 provided in a reversing path, a pair of rollers 26 and 27 is combined to be arranged, and a driving device 20 is arranged corresponding to the driving roller 26. The driving device 20 is constituted by arranging a clutch 23 and a torque limiter 24 on a shaft 22 and transmits driving force from a gear for normal rotation G4 and a gear for reverse rotation G5. In the case of normal rotation, an input shaft is driven by the combination of the gears G1 and G4, and in the case of reverse rotation, the gears G2, G3 and G5 are combined through the clutch 23 and the torque limiter 24 is allowed to slide to reversely drive the shaft. The driving force is always transmitted to the driving shaft through the torque limiter, and only in the case of reverse rotation, the clutch is actuated to switch the normal and reverse rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for transporting a sheet to an intermediate tray in an automatic double-sided copying machine, and more particularly to a forward / reverse drive roller device for transporting a sheet from an inversion path toward the intermediate tray. The present invention relates to a drive device that facilitates switching of driving in the opposite direction.

[0002]

2. Description of the Related Art In an image forming apparatus equipped with an automatic double-sided copying function, an image is formed on one side of a sheet, a single-sided copy sheet is made through a fixing device, and then the recording sheet is temporarily stored in an intermediate tray. Is provided. Then, when the back-side copy mode is set, the single-sided copy paper stored in the intermediate tray is fed again, another image is transferred to the back surface of the paper, and the image is fixed through the fixing device to form a double-sided copy. After it is completed, it is ejected to the ejection tray. As the automatic double-sided copying machine, for example, an apparatus as disclosed in Japanese Patent Laid-Open No. 3-267271 is used.

In the above-mentioned conventional automatic double-sided copying machine, a plurality of paper feed trays and an intermediate tray are arranged, and paper feed paths from the respective paper feed trays are arranged vertically on the side of the main body. Connected to. Then, the paper fed from an arbitrary paper feed tray is sent toward the image transfer portion from the photoconductor drum so that a copy can be created. Further, the paper on which the toner image is transferred from the photosensitive drum is fixed through a fixing device and the copy is ejected toward the ejection tray. On the other hand, when the double-sided copy mode or the multiplex copy mode is set, the single-sided copy paper discharged from the fixing device is branched from the discharge path toward the return path and fed toward the intermediate tray. I have to. For example, in the multiplex mode, it is sent out directly from the return path to the intermediate tray, but in the double-sided mode, a mechanism is used in which it is sent to the intermediate tray in a state of being inverted by the inversion path connected to the return path.

In the forward / reverse drive roller device provided in the reverse path, it is necessary to drive the paper in the forward rotation direction when feeding the paper, and to drive the paper in the reverse rotation direction when feeding the paper toward the intermediate tray. A forward / reverse driving mechanism is arranged for the forward / reverse driving roller device. The forward / reverse drive mechanism for the forward / reverse drive roller device may be, for example, an actual opening 1-1.
It is known to use a friction drive mechanism as shown in JP 37952 and a gear drive mechanism as shown in JP-A-2-209343.
By arranging the forward / reverse drive mechanism with respect to the forward / reverse drive roller device, it is possible to easily cope with the mode of sheet transport on the reverse path and easily perform the transport operation of the single-sided copy sheet. it can.

[0005]

However, the conventional reversing drive mechanism as described above has a problem that the number of members used for switching the driving force is large and the mechanism of the apparatus is complicated. There is a problem that it becomes an obstacle when the forming apparatus is configured in a small size. Further, since the mechanism for switching the drive uses means for changing the meshing of gears and the like, there is a problem in the reliability of the drive mechanism.
In particular, as disclosed in Japanese Utility Model Application Laid-Open No. 1-137952, in a device using a friction drive mechanism, a response is caused by a decrease in frictional force due to long-term use and a change in environment (especially at low temperature). There is also a problem of deterioration in sex. If the response is delayed when switching the rotation direction, a problem may occur such that the next sheet collides with the sheet that has been reversed and sent toward the intermediate tray, and a jam occurs. .

Further, when the processing speed in the image forming apparatus becomes high, it is required to make the paper conveying speed in the reverse path high. Therefore, for example, when the forward / reverse driving roller device is reversely driven, It is required to set the rotation speed of the roller to a high speed. On the other hand, the conventional device for switching the meshing direction of the gears has a problem that the impact at the time of switching the drive becomes large. In a device that uses a drive force transmission system by meshing gears, noise may be generated when the gears are switched, and it is necessary to take measures such as taking measures against noise.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional reversing and conveying device, and is configured as a device in which a clutch member and a torque limiter are combined with a drive shaft for a forward / reverse driving roller device. However, it is an object of the present invention to provide a device that can switch the transport direction quickly and that can simplify the configuration of the device.

[0008]

According to the present invention, a downstream side and a branching path of a conveyance path are arranged in the middle of a paper conveyance path via a switching gate, and forward / reverse driving is performed at a position on the downstream side of the conveyance path. A roller device is arranged, a mechanism for branching the paper toward the branch path is provided through the switching gate, and the forward / reverse drive roller device is driven in the forward direction to transfer the paper from the transport path to the downstream side of the transport path. The present invention relates to a sheet transporting device configured to transport a sheet from a downstream side of a transporting path to a branching path through a switching gate by performing a function of transporting the sheet toward a sheet and driving the forward / reverse driving roller device in a reverse direction. . In the present invention, the torque control means is arranged with respect to the drive roller shaft of the forward / reverse drive roller device arranged on the downstream side of the conveyance path, and the rotation torque is always applied to the drive shaft in a constant rotation direction, A mechanism for providing a means for interrupting the rotational force in the reverse rotation direction, the means for interrupting the rotational force in the reverse rotation direction is constituted by a clutch member, and a mechanism for switching the sheet conveying direction in the forward / reverse drive roller device by the action of the clutch member. Are configured.

Further, in the present invention, the drive torque control means and the means for interrupting the rotational force can be arranged coaxially with the axis of the drive roller. further,
In the present invention, either the torque control means or the means for interrupting the rotational force can be arranged on each of the pair of roller shafts of the forward / reverse drive roller device. In addition to the above configuration, in the present invention, the direction in which the driving force is transmitted by the means for interrupting the rotational force can be set to the direction in which the sheet is fed toward the intermediate tray, and the driving force in the sheet conveying direction can be set. Can be transmitted using a torque limiter. The above-mentioned mechanism can be incorporated into a mechanism that reverses and stores single-sided copy paper in an intermediate tray of an automatic double-sided copying machine. In that case, the intermediate tray is configured as a branch path and is provided downstream of the transport path. The side may be configured as an inversion path, and the forward / reverse drive roller may be arranged in the inversion path.

By configuring as described above, in the sheet reversing device of the image forming apparatus of the present invention, it is possible to reduce the number of parts required to drive the forward / reverse driving roller device, and the device can be constructed. It can be miniaturized. Further, the means for applying one rotational torque to the drive shaft of the forward / reverse drive roller device is constituted by the torque limiter, so that the manufacturing cost of the device can be reduced. Further, since the driving gear and the driven gear always maintain the meshing relationship, the response of the switching of the driving direction can be favorably maintained, and the reliability can be improved. Also in the sheet reversing device of the present invention, the reversing sheet needs to reach the branch path by the time the next sheet arrives. In comparison with the above, the forward / reverse drive roller provided on the downstream side transport path needs to set a high transport speed.
Therefore, also in the present invention, when the sheet is conveyed in a state where it is nipped between the conveying roller device on the sheet conveying path and the forward / reverse driving roller, the sheet is driven in the forward / reverse direction until it exits the conveying roller device. Although the rollers perform the transportation operation while slipping, the general transportation mode is that the rollers are transported at a high speed in accordance with the speed of the forward / reverse driving rollers after passing through the restriction portion by the transportation roller device. On the other hand, in the apparatus of the present invention, the drive of the roller in the forward / reverse drive roller apparatus is controlled via the torque limiter, so that slippage between the roller and the paper is prevented, and the wear of the roller member and Therefore, the rotation speed does not fluctuate, and the device can be operated in a stable state without abnormal noise or load fluctuation.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet reversing device of an image forming apparatus according to the present invention will be described with reference to the illustrated example. The electrophotographic copying machine 1 shown in FIG. 1 is an example of an automatic double-sided copying machine to which the reversing conveyance mechanism of the present invention is applied. In the electrophotographic copying machine 1, a plurality of paper feed trays 5, 5a ... Are provided for the photoconductor drum 2 that forms a toner image by using the electrophotographic method.
, And the sheet feeding means from the intermediate tray 6 is arranged. The paper feed mechanism from the paper feed tray or the like feeds the paper by the paper feed rollers 7 provided in the respective paper feed trays, and conveys roller devices 8a and 8b arranged in the paper conveyance path 8 to the photosensitive drum 2 It is conveyed toward the matching device 9 in the upstream portion. Then, between the registration roller device 9a and the pre-registration roller device 9b provided in the aligning device 9, a loop is formed on the paper to perform the aligning operation, and the timing is adjusted to the toner image formed on the photosensitive drum. Send out the paper and transfer the toner image.

The sheet on which the toner image has been transferred as described above is fixed by the fixing device 3 and discharged toward the discharge tray 4. When the electrophotographic copying machine is set to the double-sided copy mode, the single-sided copy sheet is not directly discharged, but is branched toward the return path 10 and conveyed in the return path via the conveyance roller device 11. Then, it is fed toward the inversion path 12. The inversion path 12
Is provided with a forward / reverse drive roller device 13. When the rear end of the sheet is detected by the sensor S, the drive direction of the forward / reverse drive roller device 13 is switched to convey the sheet in the reverse direction. I do.

In the vicinity of the forward / reverse drive roller device 13,
A paper feed path directed to the intermediate tray 6 via the switching gate 15 is connected, and the paper is sent toward the intermediate tray 6 by the reverse drive of the forward / reverse driving roller device and the switching of the switching gate. The single-sided copy sheet stored in the intermediate tray 6 in the inverted state is driven by the sheet feeding roller 7b in accordance with the back side copy mode.
The image is sent from the photoconductor drum to the image transfer portion via the sheet conveyance path 8, and an image is formed on the back side in the same manner as in normal copying, and the double-sided copy is ejected toward the ejection tray. To do so.

When feeding a sheet to the intermediate tray, as shown in FIGS. 2 and 3, reversal conveyance is performed in the reversal path 12 and the switching gate 15 is switched. The example shown in FIG. 2 shows a state in which the paper is conveyed from the return path 10 to the reversal path 12, and until the rear end of the paper is detected by the sensor S, the forward / reverse drive roller device 13 is The sheet is driven in the normal rotation direction, and the operation of conveying the sheet toward the reverse path 12 is continued. When the rear end of the sheet is detected by the sensor S and a predetermined time elapses, the switching gate 15 is swung so as to close the reversing path 12, and the conveyance path for the intermediate tray 6 becomes the reversing path 12. Connected. At the same time, the forward / reverse drive roller device 13 is driven in the reverse direction, and the sheet is transported toward the intermediate tray 6 by using the forward / reverse drive roller device 13 and the transport roller device 16. After that, when a predetermined time elapses after the trailing edge of the sheet is detected by the sensor, the switching gate 15 is returned to the position shown in FIG. 2, and the return path 10 and the reversing path 12 are connected.

[0015]

[Drive Mechanism 1 for Forward / Reverse Drive Roller Device] As described above, the drive mechanism for the forward / reverse drive roller device is shown in FIGS. 4 and 5 in order to reversely convey the sheet from the reverse path toward the intermediate tray. Can be configured to. In the drive device 20 of the present invention, the drive roller 26 and the pinch roller 27 are arranged to face each other to form a forward / reverse drive roller device 25 in the reversing path, and the drive shaft 22 of the drive roller 26 has a clutch member. 23 and two output gears G4, G
5 are arranged. The output gear G4 is configured as a mechanism that transmits a driving force to the drive shaft 22 via the torque limiter 24, and is used when the transport roller device is driven in the normal rotation direction. Further, the output gear G5 transmits the driving force to the drive shaft with the clutch member 23 turned on.

In the drive mechanism for the drive shaft, two input gears G1 and G2 are provided for an input shaft 21 connected to a shaft such as a motor, and the output gear G1 is the output gear G.
4 directly meshes with each other to form a drive force transmission system for driving the drive roller in the forward direction. Also, the input gear G2
The idler gear G3 is arranged between the output gear G5 and the output gear G5 to form a mechanism for transmitting the driving force in the reverse direction to the drive shaft in the state where the clutch member 23 is connected.
The clutch member 23 can use an electromagnetic clutch. The clutch member 23 is turned on to output the output gear G5 only when the forward / reverse driving roller device is driven in reverse.
The drive shaft is driven via.

In the drive device 20 of the present invention provided with the drive mechanism as shown in FIGS. 4 and 5, the forward / reverse drive roller device 25 is driven in the forward rotation direction so that the paper is directed from the return path to the reverse path. When carrying, input gear G1 and output gear G4
The transmission system of the driving force between and is used, and the driving force is controlled by the torque limiter 24. Then, the driving speed of the forward / reverse driving roller device 25 can follow the speed of the conveying roller device in the return path to exhibit the action of conveying the sheet at a predetermined speed. On the other hand, when the forward / reverse drive roller device is driven in the reverse direction, the clutch member 23 is turned on and the input gear G2 and
The driving force is transmitted in mesh with the idler gear G3 and the output gear G5.

When the forward / reverse drive roller device 25 is driven in the reverse direction, the drive state of the normal drive system is maintained, but the torque limiter 24 slips to rotate the output gear G4 to the clutch member. Since it is transmitted to the drive shaft via 23, the forward / reverse drive roller device is driven in the reverse direction. Since the reverse drive state of the forward / reverse drive roller device is set at the same time when the clutch member 23 is turned on, a delay in reverse drive timing is prevented. Further, the clutch member 2
Even when the switch 3 is turned off, the normal rotation state is immediately returned, so that the roller member does not run idle or generate excessive friction.

[0019]

[Driving Mechanism 2 for Forward and Reverse Driving Roller Device] FIG.
In addition to the drive device shown in FIG. 5, in the present invention, as shown in FIGS. 6 and 7, it is possible to use a mechanism for switching the input shaft during forward and reverse drive. In the example shown in FIGS. 6 and 7, the two roller members 41 and 42 forming the drive device 40 are supported by the forward rotation shaft 37 and the reversal shaft 34, respectively. A normal rotation gear 36 and a torque limiter 38 are arranged on the normal rotation shaft 37, and a reverse gear 33 and a clutch member 35 are arranged on the reverse shaft 34. The input gear 32 is arranged so as to mesh with both of the two output gears 33 and 36, and the input gear 32 is driven by the input shaft 31.

In the drive unit 30, when the forward / reverse drive roller unit is driven in the forward rotation direction while the sheet is conveyed from the return path to the reverse path, the clutch member 35 is in the off state. Set to input gear 32 and gear 36
The forward rotation shaft 37 is driven by the meshing of. Then, in that state, the roller 41 functions as a driving roller and the other roller 42 functions as a pinch roller,
According to the drive torque value set in the torque limiter 38, the operation of conveying the sheet is performed. On the other hand, when the clutch member 35 is turned on and the gear 33 and the shaft 34 are connected, the state of driving the reversing shaft 34 is set, and the reversing roller 42 is in the state of conveying the paper in the reversing direction.
At that time, since the torque limiter 38 slides due to the application of the driving force in the opposite direction, the forward rotation roller 41 rotates following the rotation of the reverse roller and conveys the paper from the reverse path toward the intermediate tray. .

As described above, also in the examples shown in FIGS. 6 and 7, while the input gear 32 is always driven in the same direction, the two input gears are engaged with each other, and the action of the clutch member and the torque limiter is used. Thus, the driving direction of the transport roller device can be switched between the forward and reverse directions so that the transport action of the sheet can be exhibited. Further, in the apparatus of the present invention, the driving force is transmitted to the one shaft in the forward rotation direction through the torque limiter, so that the forward rotation roller is also conveyed during the reverse conveyance. Can be driven depending on the action of the torque limiter. Therefore, following the operation in which the clutch member is turned on and off,
The transport roller device can be arbitrarily switched in the forward and reverse directions, and the drive can be switched in an instant.

[0022]

[Other Structure of Clutch Member and Operation of Driving Device] In the examples shown in FIGS. 4 to 7, the clutch member is composed of an electromagnetic clutch, but in the present invention,
As the clutch member, as shown in FIG. 8, a device in which a solenoid and a spring clutch are combined can be used. In the example of the spring clutch shown in FIG. 8, a spring clutch 43 is arranged between the reversing gear 33 and the reversing shaft 34 in the drive device arranged as shown in FIG. Is provided by projecting the claw member 44. Further, a locking claw member 47 driven by a solenoid 45 is arranged with respect to the spring clutch 43, and the claw members 44, 47 are arranged.
Make sure to connect the clutch while and are engaged.

In the example of the spring clutch described above, as shown in FIG. 9, when the claw 47 of the arm 46 is engaged with the claw 44 of the spring clutch 43, the spring clutch 43 includes the reversing shaft and the gear 33. No connection relationship is set. Also, the arm 46 is a spring 48.
Since the non-engaged state is maintained by, the reversing shaft is in a state of idling, and only the normal direction driving is performed. On the other hand, as shown in FIG. 10, when the solenoid 45 is energized, the claw 47 of the arm member 46 separates from the claw 44 of the spring clutch, so the spring clutch rotates together with the reversing gear and the gear 33. The driving force of is transmitted to the reversing shaft. Therefore, as shown in FIG. 8, even when the spring clutch is used, the switching operation of the drive direction can be easily performed as in the case of the electromagnetic clutch.

As described above, when the clutch member and the torque limiter are combined to form the drive mechanism, each operating member operates as shown in the timing chart of FIG. In the timing chart of FIG. 11, when the sensor S detects the leading edge of the sheet and then outputs a signal that detects the trailing edge of the sheet, the clutch member is immediately turned on and the sheet branches. The reverse conveyance state is maintained until the end of passing. Also, following the ON operation of the clutch member,
The switching gate is switched so that the switching gate is switched to guide the sheet from the reversing path toward the intermediate tray. In the timing chart of FIG. 11, if a slight time lag is provided in the switching operation of the clutch member and the switching gate after the sensor detects the trailing edge of the sheet, the sheet may jam. It is possible to exert the effect in preventing.

Further, in order to operate the drive device of the mechanism as described above, in the present invention, the control device 50 as shown in the block diagram of FIG. 12 can be used. In the block diagram of FIG. 12, a CPU 51 for performing an arithmetic operation, a memory 52 such as a RAM and a ROM, and a timer 53 are arranged, and are set in the memory as in the case of a general copying machine control device. Operate each controller according to the program. In the control device 50, a means for taking in a signal from the sensor and other external signals through the I / O port and outputting a drive signal output from the CPU from the driver circuit 55 is configured. ing. Then, a signal for detecting the trailing edge of the sheet can be input to the control device to switch the switching gate and control the operation of the clutch member. In the above-described apparatus of the present invention, it is possible to use a method of inputting a signal that detects the trailing edge of the paper to the control device when the paper is conveyed from the reversing path toward the intermediate tray. In addition, it is also possible to configure a mechanism in which one sensor detects the paper on the reverse path and the branch path.

[0026]

Since the sheet reversing device of the image forming apparatus of the present invention constitutes the device having the above-mentioned mechanism, the number of parts required for driving the forward / reverse driving roller device can be reduced. It is possible to downsize the device. Further, the means for applying one rotational torque to the drive shaft of the forward / reverse drive roller device is constituted by the torque limiter, so that the manufacturing cost of the device can be reduced. Further, since the driving gear and the driven gear always maintain the meshing relationship, the response of the switching of the driving direction can be favorably maintained, and the reliability can be improved. Further, in the device of the present invention, slippage is prevented from occurring in the transport roller device, so that wear of the roller member, fluctuations in rotation speed, etc. do not occur, and abnormal noise, load fluctuations, etc. do not occur. In addition, the device can be operated in a stable state.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an electrophotographic copying machine to which a forward / reverse driving roller device of the present invention is applied.

FIG. 2 is an explanatory diagram of a sheet conveyance state in the forward / reverse driving roller device of the present invention.

FIG. 3 is an explanatory diagram of a state in which a sheet is sent toward an intermediate tray.

FIG. 4 is a side view of the first embodiment of the driving device of the present invention.

5 is a front view showing the relationship of gear members in the apparatus of FIG.

FIG. 6 is a side view of a second embodiment of the driving device of the present invention.

7 is a front view showing the relationship of gear members in the apparatus of FIG.

FIG. 8 is a front view showing another configuration of the clutch member of the present invention.

9 is a side view showing a state in which the clutch member of FIG. 8 is turned off.

FIG. 10 is a side view showing a state where the clutch member of FIG. 8 is turned on.

FIG. 11 is a timing chart of switching of the sheet conveyance direction in the apparatus of the present invention.

FIG. 12 is a block diagram showing a configuration of a control device of the present invention.

[Explanation of symbols]

1 Electrophotographic copying machine, 2 Photosensitive drum, 3
Fixing device, 6 intermediate trays, 10 return path,
12 reversing path, 13 forward / reverse driving roller device, 15
Switching gate, 20 drive device, 21 input shaft, 23 clutch member, 24 torque limiter, 25 forward / reverse drive roller device, 30 drive device, 35 clutch member, 38 torque limiter, 43 spring clutch, 45 solenoid, 50 control device, G1・ G2 input gear,
G4 / G5 output gear.

Claims (4)

[Claims] 1. A downstream side of a conveyance path and a branch path are arranged via a switching gate in the middle of a sheet conveyance path, and a forward / reverse drive roller device is arranged at a middle position on the downstream side of the conveyance path. A mechanism for branching the sheet toward the branch path is provided, and by driving the forward / reverse drive roller device in the forward rotation direction, the sheet is transported from the transport path toward the downstream side of the transport path. In the paper transporting device configured to transport the paper from the downstream side of the transporting path toward the branch path via the switching gate by driving the forward / reverse driving roller device in the reverse direction, the normalizing roller arranged on the downstream side of the transporting path. Torque control means is arranged for the drive roller shaft of the reverse drive roller device, and means for intermittently applying rotational torque to the drive shaft in a constant rotation direction and interrupting the rotational force in the reverse rotation direction is provided. A sheet reversing device for an image forming apparatus, characterized in that a means for interrupting the rotational force in the direction is constituted by a clutch member, and the action of the clutch member causes the forward / reverse drive roller device to switch the sheet conveying direction. 2. The sheet reversing device for an image forming apparatus according to claim 1, wherein the torque control means and the means for interrupting the rotational force are arranged coaxially with the axis of the drive roller. . 3. The torque control means and the means for interrupting the rotational force are arranged on each of a pair of roller shafts of a forward / reverse driving roller device.
The sheet reversing device of the image forming apparatus according to item 1. 4. The image according to claim 1, wherein the direction for transmitting the driving force by the means for interrupting the rotational force is made to coincide with the direction for feeding the sheet toward the branch path. Paper reversing device of forming device.