JPH05286599A - Paper feeding device - Google Patents

Abstract

PURPOSE:To convey all the paper to be conveyed accurately to a reference position in a paper feeding device which can be switched to the separate conveying state or to the normal conveying state and conveys a plurality of paper to be conveyed in the parallel state in the normal conveying state. CONSTITUTION:This is a paper feeding device which can be switched to the skate for separate conveying or the state where a plurality of envelopes EL are conveyed not separately in the parallel state as a reverse-rotation roller shaft 32 provided with a reverse-rotation roller 6 is switched to the reverse- rotation driving state or the free rotation state. Between the reverse-rotation roller 6 and the reverse-rotation roller 32, a friction clutch 34 for torque limiting for transmitting only the torque less than a predetermined value between them, and a one-way clutch 35 which allows relative rotation of the reverse-rotation roller shaft 32 against the reverse-rotation roller 6 only in the forward rotation direction are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in an image forming apparatus such as a printer and switches between a state in which a sheet of paper is conveyed while being separated from a predetermined reference position, and a state in which it is normally conveyed without separating it. The present invention relates to a paper feeding device.

[0002]

2. Description of the Related Art Some conventionally known sheet feeders are capable of switching between a state in which conveyed sheets are conveyed while being separated, and a state in which they are normally conveyed without separating them, and further, envelopes and the like. There are some narrow-width transport papers that have a function of simultaneously feeding a plurality of these in parallel with each other.

An example of such a device is shown in FIGS.
In FIG. 6, 90 is a registration roller pair, and the registration roller pair 90 aligns the leading edge of the conveyed paper. At a position on the front side of the registration roller pair 90 in the transport direction, two pairs of forward rotation rollers 91 and reversal rollers 92 that are in pressure contact with each other are arranged side by side, and the pressure contact positions of both rollers 91 and 92 (that is, the conveyance paper Between the registration roller pair 90 and the nip position), two left and right registration switches 9 are provided.
3 is provided. The registration switch 93 detects the timing for stopping the conveyance drive and activating the registration roller pair 90 after the leading edge of the conveyed paper reaches the registration roller pair 90, and all the registration switches 93 convey the conveyance paper. The rotation drive of the forward rotation roller 91 is stopped after a predetermined time has elapsed from the time when the leading edge of the paper was detected.

As shown in FIG. 7, the forward rotation roller 91 and the reversal roller 92 are provided on the left and right sides corresponding to the conveying path of the envelope EL.
The reversing roller 92 is provided at a position where it is relatively rotatably mounted on a single reversing roller shaft 94 extending in a direction parallel to the pair of registration rollers 90. The reversing roller shaft 94 is connected to the main motor 96 via a clutch 95, and by turning the clutch 95 on and off,
The state of being driven to rotate in the direction of arrow A1 (reversal direction) in FIG. 6 and the state of free rotation can be switched. Further, a torque limiting friction clutch 97 is provided between each reversing roller 92 and the reversing roller shaft 94, and each friction clutch 97 is fixed between the reversing roller 92 and the reversing roller shaft 94. It is configured to transmit only a torque equal to or less than a value.

In such an apparatus, for example, when the normal paper is fed to the registration roller pair 90 while being separated,
The forward rotation roller 91 is rotationally driven in the direction in which the sheet is conveyed (normal rotation direction; arrow direction in FIG. 6), and the clutch 95
Is turned on, and the reversing roller shaft 94 is rotationally driven in the reversing direction, that is, the direction of arrow A1 in FIG. Here, the reversing roller shaft 9 is generated by the frictional force due to the pressure contact between the rollers 91 and 92 until the conveyed paper reaches between the rollers 91 and 92.
Since the torque in the forward direction of four turns exceeds the transmittable torque of the friction clutch 97, each reversing roller 92
Is reverse to the direction of rotation of the reversing roller shaft 94 (see FIG. 6).
Rotate in the direction of arrow A2). However, both rollers 9
When the normal paper is nipped between the first and second papers, that is, when the reverse roller 92 and the normal paper come into contact with each other, the forward rotation torque decreases and falls below the transmissible torque. It is rotationally driven in the reversing direction integrally with the reversing roller shaft 94 via 97. While the normal paper is separated by the reversing roller 92, the normal paper is conveyed toward the registration roller pair 90 by the forward rotation roller 91. Then, the drive of the forward rotation roller 91 is stopped after a lapse of a predetermined time from the detection of the front end of the normal paper by the registration switch 93, whereby the front end of the normal paper reaches the registration roller pair 90. Stop at.

On the other hand, for example, when two envelopes EL are conveyed in a parallel state without being separated, the clutch 95 is turned off and the reversing roller shaft 9 is conveyed in order to perform normal conveyance.
4 is in a free rotation state. As a result, each reversing roller 92 rotates in the normal rotation direction in synchronization with the rotation of the normal rotation roller 91, and the envelopes EL are normally conveyed by the rollers 91 and 92 toward the registration roller pair 90.

[0007]

In the above-mentioned paper feeding device, when the envelopes EL are conveyed in parallel, the conveying speeds of the envelopes EL vary, so that both the envelopes EL are completely at the same time.
It is not always nipped by 1, 92, and as shown in FIG. 7, one envelope EL may be loaded later than the other envelope EL.

In this case, when a predetermined time has passed after the preceding envelope EL passed the detection position of the registration switch 93, the envelope EL reaches the registration roller pair 90 and stops as shown in the figure. Since the rotation drive of the forward rotation roller 91 is continued, the delayed conveyance of the envelope EL is still continued. However, in this state,
The reversing roller 92 (the left reversing roller 92) that is in contact with the preceding envelope EL that is stopped causes frictional force F from the envelope.
The torque T in the reversal direction generated by this frictional force F
Is transmitted to the reversing roller shaft 94 via the friction clutch 97 (friction clutch 97 on the left side in the drawing), the delayed conveyance of the envelope EL is braked by that amount, and the conveyance speed is reduced. Become. Therefore, even if a predetermined time elapses after the front end of the envelope EL passes the detection position of the registration switch 93, the envelope EL
Cannot reach the registration roller pair 90, and the drive of the forward rotation roller 91 is stopped without reaching the registration roller pair 90, which causes a problem that the leading end position of the envelope EL is misaligned.

In view of the above-mentioned circumstances, the present invention is designed to switch between a separate conveyance state and a normal conveyance state, and in a paper feeding device for conveying a plurality of conveyance papers in a parallel state in the normal conveyance state, all conveyance papers are conveyed. It is an object of the present invention to provide a sheet feeding device that can favorably convey a sheet to a reference position.

[0010]

DISCLOSURE OF THE INVENTION The present invention is capable of switching between a state in which conveyed sheets are conveyed while being separated and a normal conveyed state, and at least in the normal conveyed state, a plurality of conveyed sheets are arranged in parallel with each other. In a paper feeding device configured to convey at one time until the front end of the sheet reaches a predetermined reference position, a forward rotation roller that rotates in a direction in which the sheet is conveyed toward the reference position, and the forward rotation roller. A reversing roller shaft that is provided at a position opposed to, extends in the parallel direction of the transport paper, and is switched between a reversing drive state and a free rotation state in which it is rotationally driven in the same direction as the rotation direction of the forward rotation roller;
The reversing roller shaft is provided with a plurality of reversing rollers which are mounted at positions corresponding to the conveying paths of the respective conveying papers and which come into contact with the normal rotating rollers in a state where the conveying papers do not pass through. Torque limiting means for transmitting only torque equal to or less than a constant value between the reversing roller shaft and the reversing roller shaft, and allowing relative rotation of the reversing roller shaft with respect to the reversing roller only in a direction opposite to the rotation direction of the forward rotation roller. The rotation direction regulating means are respectively interposed (Claim 1).

Further, according to the present invention, it is possible to switch between a state in which the conveying paper is conveyed while being separated and a normal conveying state, and at least in a state in which the plural conveying papers are arranged in parallel with each other, the leading end of each conveying paper is predetermined. In a paper feeding device configured to convey at one time until the reference position is reached, a forward rotation roller that rotates in a direction that conveys the conveyance paper toward the reference position, and a position facing the forward rotation roller. A reverse rotation state and a free rotation state in which the sheet is extended in the parallel direction and is driven to rotate in the same direction as the direction of rotation of the forward rotation roller via a drive transmission means arranged at one end side thereof. And a plurality of reversing rollers mounted at positions on the reversing roller shaft corresponding to the conveying paths of the respective conveying papers and contacting the forward rotating roller in a state where the conveying papers have not passed. And a rotation direction restricting means that allows relative rotation of the reversing roller shaft with respect to the reversing roller only in a direction opposite to the rotation direction of the forward rotating roller. A torque limiting means is provided between the drive transmission means and the reversing roller shaft to transmit only a torque equal to or less than a certain value between them (claim 2).

The term "conveyed paper" as used herein is not limited to ordinary paper, but also includes flat conveyed objects such as envelopes.

[0013]

In the apparatus according to the first aspect of the present invention, when sorting and carrying the sheet, the forward rotation roller is rotationally driven in the direction in which the sheet is conveyed (normal rotation direction), and the reverse roller shaft is in the reverse direction, that is, the forward direction. It is switched to a state in which the roller is driven to rotate in the same direction as the rotating direction of the roller. Here, until the conveyed paper reaches between both rollers, the torque in the forward rotation direction around the inversion roller axis generated by the frictional force due to the pressure contact of both rollers exceeds the transmittable torque of the torque limiting means, and therefore each inversion roller is It rotates in the forward direction, which is opposite to the direction of rotation of the reverse roller shaft.
However, the forward rotation torque decreases and falls below the transmissible torque when the conveyance paper is nipped between the rollers, that is, when the reversal roller and the conveyance paper come into contact with each other. Further, it is rotationally driven in the reversing direction integrally with the reversing roller shaft through the rotation direction regulating means, and while the reversing roller separates the conveyance paper, the forward rotation roller conveys it toward a predetermined reference position. After that, the driving of both rollers is stopped at an appropriate timing, so that the conveyed paper is stopped with its leading end reaching the reference position.

On the other hand, when the conveying paper is normally conveyed in parallel, the shaft is switched to the freely rotating state. As a result, each reversing roller rotates in the forward rotation direction in synchronization with the rotation of the forward rotation roller, and the transport paper is normally transported toward the reference position by both rollers.

Here, when a certain conveyance paper is conveyed later than the other conveyance paper, the preceding conveyance paper stops when it reaches a predetermined reference position, so that it comes into contact with the preceding conveyance paper. When the reversing roller is rotating together with the reversing roller shaft, the reversing roller receives a frictional force from the contact portion with the preceding conveyance paper. However, in this apparatus, the rotation direction regulating means is interposed between the reversing roller and the reversing roller shaft, and in this rotation direction regulating means, the reversing roller axis is in the rotation direction of the forward rotation roller with respect to the reversing roller. Since the relative rotation in the reverse direction (that is, the forward rotation direction) is allowed, the reversing roller that contacts the preceding transport paper remains stationary, and the reversing roller shaft freely rotates with other reversing rollers. This makes it possible to satisfactorily convey the delayed conveyance paper to the reference position.

In the apparatus according to the second aspect of the present invention, until the conveyed paper arrives between the rollers, the reversing roller receives a force that is rotated in the direction opposite to the rotating direction of the reversing roller shaft due to the frictional force due to the pressure contact between the two rollers. work. However, in this apparatus, the rotation direction regulating means is interposed between the reversing roller and the reversing roller shaft, and the rotation direction regulating means does not permit relative rotation of the reversing roller in the reversing direction with respect to the reversing roller shaft. , The reversing roller shaft receives a force to rotate in the forward direction by the reversing roller, and the torque in the forward direction exceeds the transmittable torque of the torque limiting means. On the contrary, it rotates in the forward direction. However, the forward rotation torque decreases at the time when the conveyance paper is nipped between the two rollers, that is, the time when the reversal roller and the conveyance paper come into contact with each other, and falls below the transmissible torque. The sheet is driven to rotate in the reversing direction together with the reversing roller, and the reversing roller separates the sheet to be conveyed toward a predetermined reference position by the forward rotating roller.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows a schematic structure of an image forming apparatus provided with the paper feeding device of the present invention. This device has
A paper feed cassette 1 for containing normal paper and a paper feed cassette 2 for containing envelopes in a parallel state are detachably mounted in two upper and lower stages. As shown in FIG.
The two paper feed units 2a and 2b are arranged side by side in the width direction. Further, a magnet 30 on which the type of the cassette itself is recorded is attached to the front end (right end in FIG. 2) surface of each of the paper feed cassettes 1 and 2.

As shown in FIGS. 2 and 4, the paper feed rollers 3 and 4 are respectively provided at the positions corresponding to the paper feed cassettes 1 and 2.
Is provided. A first separating roller pair 7 composed of a forward rotation roller 5 and a reversing roller 6 is provided near the mounting position of the paper feeding cassette 1, and a forward rotation roller 8 and a reversing roller near the mounting position of the paper feeding cassette 2. A second separating roller pair 10 composed of 9 is provided. Then, the normal paper in the paper feed cassette 1 is conveyed to the registration roller pair 11 through the first separation roller pair 7 while the paper feed cassette 2
Two inner envelopes are simultaneously conveyed in parallel to the registration roller pair 11 through the second separating roller pair 10 and the first separating roller pair 7.

As shown in FIG. 2, a photoconductor 12 is installed on the downstream side of the registration roller pair 11, and around the photoconductor 12,
An image forming unit such as a charging device 13, a light emitting unit 14, a polygon mirror 15, a transfer unit 16 and the like are provided. Further, on the downstream side, a fixing unit 17, discharge roller pairs 18, 19, a discharge guide 20, a discharge tray 21 and the like are arranged.

Further, a transfer paper sensor 22 for detecting the presence or absence of the transfer paper, and a double feed of the transfer paper are provided in the transfer paper (conveyance paper) conveyance path from the paper feed cassettes 1 and 2 to the discharge tray 21. Each sensor such as a double feed sensor 23, 24 for detecting the error, a registration sensor 25 for controlling the operation timing of the registration roller pair 11, a light emission timing sensor 26, a discharge sensor 27, etc. are arranged at appropriate positions. The detection units of these sensors are arranged in parallel on the left and right so as to detect the transfer sheets fed in parallel.

In such an image forming apparatus, for example, the envelope in the paper feed cassette 2 is sent to the registration roller pair 11 through the separation roller pairs 10 and 7, where the leading end alignment is performed and then the registration roller pair 11 is carried out. Is supplied to the transfer unit 16 near the photoconductor 14. Then, after passing through the fixing unit 17, it is discharged onto the discharge tray 21 through the discharge roller pairs 18 and 19 and the discharge guide 20.

Next, a specific structure of the first separating roller pair 7 will be described with reference to FIGS. As will be described later in detail, the separation roller pair 7 is conveyed in a separation conveyance state in which normal paper conveyed from the paper feed cassette 1 is conveyed to the registration roller pair 11 while being separated and in a parallel state from the paper feed cassette 2. In addition, it is possible to switch to a normal transport state in which the two envelopes EL already separated by the second separation roller pair 10 are allowed to pass without being separated.

As shown in FIG. 1, the forward rotation roller 5 and the reverse roller 6 are provided at a plurality of locations corresponding to the conveying path of the envelope EL, and the reverse roller 6 is parallel to the registration roller pair 11. Single reverse roller shaft 3 extending in any direction
2 is attached so as to be relatively rotatable. The reversing roller shaft 32 is connected to a main motor 40 incorporated in the image forming apparatus via a clutch 38. When the clutch 38 is turned on or off, the reversing roller shaft 32 is rotationally driven in the direction of arrow A1 (reversing direction) in FIG. The state and the free rotation state can be switched.

A friction clutch (torque limiting means) 34 for limiting torque is provided between each reversing roller 6 and the reversing roller shaft 32. Each friction clutch 34 includes a reversing roller 6 and a reversing roller shaft 32.
It is configured to transmit only a torque equal to or less than a certain value between and. This torque limit value is smaller than the torque around the reversing roller shaft 32 that is generated by the frictional force due to the pressure contact between the reversing roller 6 and the normal rotation roller 5 in the reversing drive state, and the pressure contact between the reversing roller 6 and a plurality of normal sheets It is set to a value larger than the torque around the reversing roller shaft 32 that is generated by the frictional force due to.

Further, as a feature of this apparatus, a one-way clutch (rotational direction restricting means) 36 is provided between each friction clutch 34 and the reversing roller shaft 32. Each one-way clutch 36 has a reverse roller shaft 3
Only the relative rotation of the reversing roller 6 with respect to 2 in the reversing direction (direction of arrow A1 in FIG. 4), in other words, the relative rotation of the reversing roller shaft 32 with respect to each reversing roller 6 in the forward direction (direction of arrow A2 in FIG. 4) is allowed. Is configured.

The registration switch 25 is provided between the first separating roller pair 7 and the registration roller pair 11 at a position corresponding to the conveying path of each envelope EL, and all the registration switches 25 are provided. After the passage of the leading edge of the conveyed paper is detected, the rotation of the forward rotation roller 5 is stopped after a predetermined time has passed, and the registration roller pair 1
The control for starting the rotational drive of No. 1 is performed.

Next, the operation of the first separating roller pair 7 will be described.

First, when the normal paper in the paper feed cassette 1 is supplied to the registration roller pair 11, the forward rotation roller 5 is rotationally driven in the direction in which the conveyed paper is conveyed (normal rotation direction; arrow direction in FIG. 4). At the same time, the clutch 38 is switched on and the reversing roller shaft 32 is rotationally driven in the reversing direction, that is, the direction of arrow A1 in FIG. Here, until the normal paper reaches between the rollers 5 and 6, the torque in the forward direction around the reversing roller shaft 32 generated by the frictional force due to the pressure contact between the rollers 5 and 6 becomes the transmittable torque of the friction clutch 34. Therefore, each reversing roller 6 rotates in the forward direction, which is opposite to the rotation direction (reversing direction) of the reversing roller shaft 32.

However, when the normal paper is nipped between the rollers 5 and 6, that is, when the reversing roller 6 and the normal paper come into contact with each other, the normal rotation torque is reduced and becomes lower than the transmissible torque. Moreover, since the one-way clutch 36 does not allow the relative rotation of the reversing roller 6 in the normal rotation direction with respect to the reversing roller shaft 32, each reversing roller 6 is connected to the reversing roller shaft 32 via the one-way clutch 36 and the friction clutch 34. It is driven to rotate integrally in the reverse direction. While the reversing roller 6 separates the normal paper, the normal paper is conveyed toward the registration roller pair 11 by the forward rotation roller 5. Then, after the leading edge of the ordinary paper is detected by the registration switch 25, the driving of both rollers 5 and 6 is stopped after a predetermined time has passed, so that the leading edge of the ordinary paper has the registration roller pair 11 It reaches and stops in the state of being nipped.

On the other hand, the envelope EL carried out from the paper feed cassette 2 is carried into the first separating roller pair 7 in a state where it is already separated by the second separating roller pair 10, so that the first envelope is carried out. In the separation roller pair 7, the clutch 38 is switched off and the reversing roller shaft 32 is set in a free rotation state in order to carry out normal conveyance without separation. As a result, each reversing roller 6 rotates in the normal rotation direction in synchronization with the rotation of the normal rotation roller 5, and the envelopes EL are normally conveyed in parallel to the registration roller pair 11 by both the rollers 5 and 6.

Here, since the transport speed of both envelopes EL varies, both envelopes EL are completely at the same time with both rollers 5, 6.
However, as shown in FIG. 1, one envelope EL may be loaded later than the other envelope EL.

In this case, in a state where a predetermined time has passed since the preceding envelope EL passed the detection position of the registration switch 25, the envelope EL reaches the registration roller pair 11 and stops as shown in the figure. Since the rotation of the forward rotation roller 5 is continued, the delayed conveyance of the envelope EL is continued.

In this state, in the conventional apparatus shown in FIG. 7, the reversing roller 6 (the left reversing roller 6) in contact with the preceding envelope EL which is stopped receives frictional force from the envelope EL, Inversion roller shaft 38 due to frictional force
Since the torque in the reversing direction is transmitted via the friction clutch 34 (the friction clutch 34 on the left side of the drawing), the delayed conveyance of the envelope EL is braked by that amount, and the conveyance speed is reduced. However, in this embodiment, the one-way clutch 36 is provided between the reversing roller 6 and the reversing roller shaft 32. Since the relative rotation in the direction opposite to the rotation direction of 5 (that is, the forward rotation direction) is allowed, the reversing roller 6 which is in contact with the preceding envelope EL remains stationary and the reversing roller shaft 32 is rotated with respect to the reversing roller 6. Can rotate freely with the other (right side in FIG. 1) reversing roller 6. For this reason, the delayed envelope EL is satisfactorily conveyed to the reference position without being braked. Therefore, after the registration switch 25 detects the delayed envelope EL, the normal rotation is performed after a predetermined time elapses. By stopping the driving of the roller 5, the envelope EL is also accurately positioned at the nip position by the registration roller pair 11.

That is, according to this apparatus, even when the positions of the leading ends of the envelopes EL which are conveyed in parallel are varied in the normal conveying state in which the driving of the reversing roller shaft 32 is turned off, the leading ends of both envelopes EL are registered. The nip can be accurately made by the roller pair 11.

Next, a second embodiment of the present invention will be described with reference to FIG.

The components of the image forming apparatus to which the sheet feeding device of the second embodiment is applied and the components having the same functions as those of the first embodiment will be described using the same reference numerals.

The first separating roller pair 71 of the second embodiment
Is composed of a forward rotation roller 5 and a reversing roller 6 as in the first embodiment, and the reversing roller shaft 32 is rotationally driven in the same direction as the arrow A1 direction (reversing direction) in FIG. 4 by turning a clutch (not shown) on and off. The reversal drive state and the free rotation state can be switched.

As shown in FIG. 5, the first separating roller pair 7
In the configuration of No. 1, only the one-way clutch 41 is provided between each reversing roller 6 and the reversing roller shaft 32, and the drive gear 42 (driving gear) for transmitting the drive from the main motor (not shown) to the reversing roller shaft 32 is used. Transmission means) and the reversing roller shaft 32
The configuration is different from that of the separation roller pair 7 of the first embodiment in that a torque limiting friction latch 43 is provided between the above and the above.

Each one-way clutch 41 interposed between each reversing roller 6 and the reversing roller shaft 32 rotates relative to the reversing roller shaft 32 in the reversing direction of the reversing roller 6 (corresponding to the arrow A1 direction in FIG. 4). In other words, the reverse rotation direction of the reverse roller shaft 32 with respect to each reverse roller 6 (see arrow A2 in FIG. 4).
(Corresponding to the direction) is configured to allow only relative rotation.

Further, the friction clutch 43 interposed between the reversing roller shaft 32 and the driving gear 42 transmits only torque less than a certain value between the reversing roller shaft 32 and the driving gear 42. Is configured. The limit value of this torque is the reversing roller 6 in the reversing drive state.
The torque is smaller than the torque around the reversing roller shaft 32 that is generated by the frictional force due to the pressure contact between the reversing roller 6 and the normal rotation roller 5, and is larger than the torque around the reversing roller shaft 32 that is generated due to the frictional force between the reversing roller 6 and a plurality of normal papers. It is set to a value.

Next, the operation of the first separating roller 71 will be described.

First, when the normal paper in the paper feed cassette 1 is supplied to the registration roller pair 11, the forward rotation roller 5 is rotationally driven in the forward rotation direction for conveying the conveyed paper, and the clutch (not shown) is applied. The reversing roller shaft 32 is switched on.
Are rotationally driven in the reverse direction via the drive gear 42 and the friction clutch 43. Here, both rollers 5, 6
Until the normal paper arrives in the meantime, due to the frictional force due to the pressure contact between the rollers 5 and 6, the reversing roller 6 receives a force that rotates in the forward rotation direction opposite to the rotation direction (reversing direction) of the reversing roller shaft 32. work. At this time, the relative rotation of the reversing roller 6 in the reversing direction with respect to the reversing roller shaft 32 is not allowed by the one-way clutch 41, and the reversing roller shaft 32 does not rotate.
Receives a force that rotates in the forward direction. Since the torque in the forward rotation direction exceeds the transmittable torque of the friction clutch 43, the reversing roller 6 operates in the one-way clutch 4
1 and rotates in the forward direction integrally with the reversing roller shaft 32. That is, the reversing roller shaft 32 is rotated relative to the drive gear 42.

However, when the normal paper is nipped between the rollers 5 and 6, that is, when the reversing roller 6 and the normal paper come into contact with each other, the normal rotation torque is reduced and falls below the transmissible torque. Each reversing roller 6 is rotationally driven in the reversing direction integrally with the reversing roller shaft 32 via the one-way clutch 41. While the reversing roller 6 separates the normal paper, the normal paper is conveyed toward the registration roller pair 11 by the forward rotation roller 5.

On the other hand, the envelope EL carried out from the paper feed cassette 2 is carried into the first separating roller pair 71 in a state of being already separated by the second separating roller pair 10, so that the first envelope is carried out. In the separation roller pair 71, a clutch (not shown) is switched off and the reversing roller shaft is set in a free rotation state in order to perform normal conveyance without separation. As a result, each reversing roller 6 rotates in the normal rotation direction in synchronization with the rotation of the normal rotation roller 5, and the envelopes EL are normally conveyed in parallel to the registration roller pair 11 by both the rollers 5 and 6.

Here, as in the case of the first embodiment, in the case where one of the envelopes EL is loaded later than the other of the envelopes EL due to variations in the conveying speed of both envelopes EL, as shown in FIG. Then, although the preceding envelope EL reaches the registration roller pair 11 and stops, the rotation drive of the forward rotation roller 5 is continued, and the delayed conveyance of the envelope EL is continued.
At this time, the one-way clutch 41 between the reversing roller 6 and the reversing roller shaft 32 rotates the reversing roller shaft 32 relative to the reversing roller 6 in the direction opposite to the rotation direction of the forward rotation roller 5 (that is, in the forward rotation direction). Since the reversing roller 6 that is in contact with the preceding envelope EL remains stationary, the reversing roller shaft 32 is attached to the other reversing roller 6 (see FIG. 5).
It can rotate freely with the reversing roller 6 on the right side. Therefore, the delayed envelopes EL are satisfactorily conveyed without being braked, and both the envelopes EL are accurately positioned at the nip position by the registration roller pair 11.

The first separating roller pair 71 of the second embodiment.
According to the configuration of (1), not only the same effect as in the first embodiment can be obtained, but also the separating roller pair 7 of the first embodiment is provided between each reversing roller 6 and the reversing roller shaft 32. While the friction clutches (torque limiting means) 34 are provided respectively, in the second embodiment, the friction clutch 43 is provided only between the reversing roller shaft 32 and the drive gear 42. The number of friction clutches 43 can be reduced to further reduce the cost.

Further, in the first embodiment, as described above, the friction clutch 43 is provided between each reversing roller 6 and the reversing roller shaft 32. However, due to the variation of the friction clutch 43 itself, the friction clutch 43 is not provided. The torque limit value may not always be the same value. In such a case, since the torque limit value for each reversing roller 6 is different, there is a risk of causing a so-called skewing phenomenon in which the normal paper being conveyed is conveyed obliquely. On the other hand, in the second embodiment, since the friction clutch 43 is provided only between the reversing roller shaft 32 and the driving gear 42, the torque limit value for each reversing roller 6 can be made to be a complete single value. , Measures against the skew phenomenon are taken.

The present invention is not limited to the first and second embodiments described above, and the following modes can be adopted as examples.

(1) In the first embodiment, as shown in FIG. 1, the friction clutch 34, which is a torque limiting means, is directly connected to the reversing roller 6 side, and the one-way, which is a rotation direction regulating means, is connected to the reversing roller shaft 32 side. Although the one in which the clutch 36 is directly connected is shown, in the present invention, both the torque limiting means and the rotation direction restricting means may be interposed between the reversing roller and the reversing roller shaft. Even if the clutch 36 is directly connected and the friction clutch 34 is directly connected to the reversing roller shaft 32 side, the same effect as described above can be obtained.

(2) In both of the above embodiments, the case where the envelopes EL are conveyed in parallel in the normal conveyance state has been described. However, in the case where the envelopes EL other than the envelopes EL are conveyed in parallel in this normal conveyance state, for example, Envelope EL in the handling state
The present invention can also be applied to an apparatus that conveys normal paper and parallel paper.

(3) In the present invention, regardless of the number of sheets of paper to be conveyed in parallel, even in an apparatus for simultaneously conveying three or more sheets of paper in parallel, the number of reversing rollers is provided, and each roller and the reversing roller are provided. By providing the torque limiting means and the rotation direction regulating means between the shaft and the shaft, the present invention can be applied similarly to the above.

(4) In both of the above-mentioned embodiments, the two forward rotation rollers 5 and the reversal rollers 6 are provided in accordance with the number of the conveyed papers in parallel (two sheets), but in the present invention, at least the reversal roller is provided. The roller 6 may be provided individually for each sheet of paper to be conveyed, and the forward rotation roller 5 may be a single roller extending in the rotation axis direction.

(5) The torque limiting means in the present invention is not limited to the friction clutch 34 as described above, and various clutches whose transmission torque is limited to a certain value or less can be applied. Similarly, the rotation direction restricting means may use various clutches or the like that allow only relative rotation in one direction regardless of its specific structure.

[0055]

As described above, according to the present invention, the reversing roller shaft is switched between the reversing drive state and the free rotation state, so that the conveyance paper is conveyed while being separated, and the conveyance paper is arranged in parallel. In a device that can be switched to the normal transport state in which the transport is performed without any interruption, a torque limiting unit that suppresses the transmission torque to a certain value or less is interposed between the reversing roller shaft and the reversing roller, and the reversing roller shaft rotates with respect to the reversing roller. Since a rotation direction restricting means that allows only in the direction opposite to the rotation direction of the normal rotation roller (normal rotation direction) is interposed, one conveyance paper is delayed in comparison with another conveyance paper in parallel conveyance. Even if the conveying paper that has been conveyed in and comes to rest earlier and the reversing roller are in contact with each other, the reversing roller shaft rotates freely with respect to this reversing roller, so delayed conveying paper is also good. Can be conveyed to, whereby an effect capable of accurately transferring all conveying paper to a predetermined reference position.

According to the second aspect of the present invention, since the torque limiting means is provided as one unit, the cost can be further reduced and the skew phenomenon can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a paper feeding device according to a first embodiment of the present invention as seen from a direction orthogonal to a paper conveying direction and a width direction thereof.

FIG. 2 is an overall configuration diagram of an image forming apparatus provided with the paper feeding device.

FIG. 3 is a perspective view of a paper feed cassette mounted in the image forming apparatus.

FIG. 4 is a sectional front view showing a sheet feeding unit in the image forming apparatus.

FIG. 5 is a cross-sectional view of a paper feeding device according to a second embodiment of the present invention as seen from a direction orthogonal to a paper conveying direction and a width direction thereof.

FIG. 6 is a sectional front view showing an example of a conventional paper feeding device.

FIG. 7 is a cross-sectional view of the paper feeding device as seen from a direction orthogonal to a paper conveying direction and a width direction thereof.

[Explanation of symbols]

 5 forward rotation roller 6 reverse roller 7 first loosening roller 10 second loosening roller 11 registration roller pair (forms a reference position) 32 reverse roller shaft 34 friction clutch (torque limiting means) 36 one-way clutch (rotation direction regulating means) 42 Drive Gear (Drive Transmission Means) EL Envelope

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akinobu Nakahata 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Inventor Takashi Ueda 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd. (72) Inventor, Wataru Sasaki 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd.

Claims (2)

[Claims] 1. A state in which the conveying paper is conveyed while being separated and a normal conveying state are switched, and at least in the normal conveying state, a plurality of conveying papers are arranged in parallel with each other so that the leading end of each conveying paper is at a predetermined reference position. In a sheet feeding device configured to convey at a time until reaching, a forward rotation roller that rotates in a direction in which the transportation paper is transported toward the reference position, and a position that is provided at a position facing the forward rotation roller, A reversing roller shaft that extends in the parallel direction of the conveying paper and is switched between a reversing drive state in which it is rotationally driven in the same direction as the rotation direction of the forward rotation roller and a free rotation state, and conveyance of each conveying paper in the reversing roller shaft. The reversing roller and the reversing roller shaft are mounted at a position corresponding to a path, and include a plurality of reversing rollers that come into contact with the forward rotation roller in a state where the transport paper does not pass through. , And a torque limiting means for transmitting only a torque equal to or less than a constant value between them, and a rotation direction regulation for permitting relative rotation of the reversing roller shaft with respect to the reversing roller only in a direction opposite to the rotation direction of the forward rotation roller. A sheet feeding device characterized by interposing a means and a means respectively. 2. A state in which the conveying paper is conveyed while being separated and a normal conveying state are switched, and at least in the normal conveying state, a front end of each conveying paper is set to a predetermined reference position with a plurality of conveying papers arranged in parallel with each other. In a sheet feeding device configured to convey at a time until reaching, a forward rotation roller that rotates in a direction in which the transportation paper is transported toward the reference position, and a position that is provided at a position facing the forward rotation roller, Reversal that extends in the parallel direction of the conveying paper and is switched between a reversing drive state in which it is rotationally driven in the same direction as the rotation direction of the forward rotation roller and a free rotation state via a drive transmission means arranged at one end side thereof. A roller shaft; and a plurality of reversing rollers that are mounted on the reversing roller shaft at positions corresponding to the conveying paths of the respective conveying papers and that come into contact with the forward rotation roller when the conveying papers do not pass through. In addition, a rotation direction restricting means that allows the relative rotation of the reversing roller shaft with respect to the reversing roller only in the direction opposite to the rotation direction of the forward rotating roller is interposed between the reversing roller and the reversing roller shaft, and the drive is performed. A sheet feeding device, characterized in that torque limiting means for transmitting only a torque equal to or less than a predetermined value is provided between the transmitting means and the reversing roller shaft.