JPH06171788A - Paper feeding device - Google Patents

Abstract

PURPOSE:To easily select the drive of each roller with a simple structure. CONSTITUTION:When a paper feeding roller 38 is driven, a transport roller 39 is driven synchronously with the paper feeding roller 38 by a unidirectional clutch 44. At this time, the driving force is not transmitted to a resist roller because of the unidirectional clutch 45. When the resist roller 40 is driven, the transport roller 39 is driven in synchronization with the resist roller 40 by the unidirectional clutch 45. At this time, the driving force is not transmitted to the paper feeding roller 38 because of the unidirectional clutch 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device used in an image forming apparatus such as a copying machine or a laser printer.

[0002]

2. Description of the Related Art In a conventional sheet feeding device, when a sheet is conveyed to a photosensitive member, a sheet feeding roller and a conveying roller are rotated to convey the sheet to a registration roller. Then, the rotation of the paper feed roller and the conveyance roller is stopped, and then the registration roller and the conveyance roller are rotated in synchronization with the rotation timing of the photoconductor to convey the paper to the photoconductor. At this time, each roller was rotated at the same peripheral speed via the gear and the clutch by the driving force from the motor.

Recently, it is necessary to increase the paper feeding speed in order to deal with the first copy. However, since the peripheral speed of each roller is rotated according to the peripheral speed of the photoconductor, the copy speed cannot be increased beyond a certain level.

Therefore, a method has been adopted in which the speed is increased only when the paper feed roller and the transport roller are rotated.

In this method, the peripheral speed of the paper feed roller is rotated faster than the peripheral speed of the registration roller. Therefore, the transport roller is provided with a speed change mechanism for changing the peripheral speed of the transport roller in accordance with each peripheral speed. It is a thing.

In the sheet feeding device provided with this mechanism, as shown in FIG. 4, the driving force from the motor is changed from the driving gear 1 to each gear 2,
Paper feed roller 7, transport roller 8, through 3, 4, 5, 6.
It is transmitted to the registration rollers 9.

When copying is started, the drive clutch 10 is engaged, the rotation of the gear 6 is transmitted to the shaft 7a, and the paper feed roller 7 rotates.

At this time, the speed change clutch 1 of the speed change mechanism 11
When the two are connected, the gear 5 and the gear 13 are connected, and the rotational force of the gear 5 is transmitted to the gear 13. The gear 13 causes the gear 14 integrally formed on the shaft 8a of the transport roller 8 to rotate,
The transport roller 8 rotates. Since the gears 6 and 14 are set to have the same gear ratio, the peripheral speeds of the paper feed roller 7 and the transport roller 8 are the same, and the rotation of the paper causes the arrows A and B to rotate.
Is conveyed in the direction.

Next, to rotate the registration roller 9, the drive clutch 15 is engaged, and the rotation of the gear 2 drives the registration roller 9. At this time, the rotation of the gear 4 is transmitted to the conveying roller 8 by simultaneously connecting the speed change clutch 16. Then, the peripheral speeds of the registration roller 9 and the transport roller 8 are made the same by the gears 2 and 4 set to the same gear ratio.

[0010]

However, in order to match the peripheral speeds of the feed roller 7 and the registration roller 9 with the peripheral speed of the conveying roller 8 as shown in FIG. 4, a transmission mechanism 11 including a clutch and a gear is required. As a result, the assemblability was poor and the cost was significantly increased.

Further, it is necessary to actuate the drive clutches 10 and 15 and the speed change clutches 12 and 16 substantially at the same time, and the drive clutches 10 and 15 and the speed change clutches 12 and 16 are required.
There is a problem in that the combination of signals with and becomes complicated and the reliability is significantly reduced.

In view of the above, it is an object of the present invention to provide a sheet feeding device that can easily switch the driving of each roller with a simple structure.

[0013]

As shown in FIGS. 1 and 3, a means for solving the problems according to the present invention is to remove a sheet from a paper storage section 36 to a photosensitive member 26.
A sheet feeding roller 38, and
In a paper feeding device provided with a conveyance roller 39 and a registration roller 40, a first drive unit 42 for driving the conveyance roller 39 in synchronization with the paper feeding roller 38 when the paper feeding roller 38 rotates, and the registration roller. A second drive unit 43 that drives the conveyance roller 39 in synchronization with the registration roller 40 when the registration roller 40 is rotated is provided, and the first drive unit 42 is driven from the registration roller 40 by the second drive unit 43. The one-way clutch 44 that does not transmit the force to the sheet feeding roller 38 is provided, and the second driving unit 43 does not transmit the driving force from the sheet feeding roller 38 transmitted through the first driving unit 42 to the registration roller 40. A directional clutch 45 is provided.

[0014]

In the above problem solving means, when the paper is fed from the paper storage unit 36, first, when the paper feed roller 38 is driven, the first drive unit 42 causes the transport roller 39 to synchronize with the paper feed roller 38. Driven. At this time, the second drive unit 43
However, the driving force is not transmitted to the registration rollers 40 by the one-way clutch 45 of the second driving unit 43.

Then, the conveyed sheet is temporarily stopped while being caught in the registration roller 40, and then the registration roller 40 is driven.

The transport roller 39 is driven by the second drive section 43 in synchronization with the registration roller 40. At this time, the driving force is transmitted to the first driving unit 42, but the first driving unit 4
The driving force is not transmitted to the paper feed roller 38 by the two-way clutch 44 of 2.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a sheet feeding device showing an embodiment of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a general block diagram of a copying machine.

In the copying machine of this embodiment, as shown in FIG. 3, an original cover 21 is provided on the upper portion of the main body 20 of the copying machine, and an original table 22 is arranged on the lower surface of the original cover 21. An optical system 27 that irradiates a document with light by a lamp 23 and exposes the reflected light to a photoconductor 26 via a mirror 24 and a lens 25, a developing device 28 arranged around the photoconductor 26, and a transfer device. 29, a cleaning device 30,
A charging device 31, a fixing device 32 for fixing the toner on the paper transferred by the photoconductor 26, a paper discharge roller 33 for discharging the paper from the fixing device 32, and a paper discharge for receiving the discharged paper. A tray 34 and a paper feeding device 35 for feeding paper to the photoconductor 26 are provided.

The paper feeding device 35 is provided with a storage cassette 36 for storing the paper and a transport path 37 for transporting the paper from the storage cassette 36 to the photoconductor 26, and the transport path 37 is located on the upstream side in the paper transport direction. From the top to the downstream side, the paper feed roller 38 that sequentially feeds the paper in the storage cassette 36 from the top, the conveyance roller 39 that feeds the paper fed by the paper feed roller 38 to the downstream side, and the conveyance roller 39. There is provided a registration roller 40 that temporarily stops the sheet fed from the front side of the photoconductor 26 and feeds the sheet to the photoconductor 26 in synchronization with the rotation timing of the photoconductor 26. And
As shown in FIG. 1, the driving force from the motor is transmitted to the rollers 38, 39, 40 through the gear mechanism 41.

A first drive unit 42 for driving the conveying roller 39 in synchronization with the sheet feeding roller 38 when the sheet feeding roller 38 rotates, and a conveying roller in synchronization with the registration roller 40 when the registration roller 40 rotates. A second drive unit 43 that drives 39 is provided.

Then, the one-way clutch 44 which does not transmit the driving force from the registration roller 40 transmitted to the first driving section 42 through the second driving section 43 to the sheet feeding roller 38.
The second drive unit 43 is provided with a one-way clutch 45 that does not transmit the driving force from the paper feed roller 38 transmitted via the first drive unit 42 to the registration roller 40.

The conveyance path 37 guides the paper in the storage cassette 36 toward the photoconductor 26, and therefore the paper guide 46 and the conveyance guide curved in a substantially U shape from the upstream side to the downstream side in the paper conveyance direction. It is formed from a plate 47.

As shown in FIG. 1, two paper feed rollers 38 are arranged in the paper width direction, and are externally fitted to a roller shaft 38a rotatably provided on the copying machine main body 20 via a bearing 48.

Two of the transport rollers 39 are arranged in the paper width direction, and are externally fitted to a roller shaft 39a which is rotatably provided on the copying machine main body 20 via a bearing 49.

Two of the registration rollers 40 are arranged in the width direction of the paper, and are externally fitted to a roller shaft 40a rotatably provided on the copying machine main body 20 via a bearing 50.

The gear mechanism 41 includes a drive gear 51 rotated by a drive force from a motor, a gear 52 meshing with the drive gear 51, rotatably fitted to a registration roller shaft 40a, and an idle shaft meshing with the gear 52. Idle gear 54 rotatably fitted in 53 and idle gear 54
A gear 55 rotatably fitted on the meshing conveyance roller shaft 39a, an idle gear 57 rotatably fitted on the gear 55 and an idle shaft 56 meshing with the gear 55, and an idle gear 5
7 and a gear 58 rotatably loosely fitted to the meshing feed roller shaft 38a.

Then, the first drive clutch 59 is attached to the gear 58.
Are provided intermittently, and the driving force from the gear 58 is transmitted to the roller shaft 38a of the paper feed roller 38 by a signal from a control device (not shown). Further, the gear 52 is provided with a second drive clutch 60 which can be intermittently connected, and transmits a driving force from the gear 52 to the roller shaft 40a of the registration roller 40 by a signal from the control device.

The first drive section 42 includes a pulley 61 loosely fitted on the roller shaft 38a of the paper feed roller 38, and a first pulley 62 fitted on the roller shaft 39a of the transport roller 39.
A belt 63 wound around the pulley 61 and the first pulley 62, and a one-way clutch 44.

The second drive section 43 is provided for the registration roller 4
No. 0 roller shaft 40a is loosely fitted to the pulley 64, and the conveying roller 39 is fitted to the roller shaft 39a outside the second pulley 65.
And a belt 66 wound around the pulley 64 and the second pulley 65, and a one-way clutch 45.

The one-way clutch 44 is, as shown in FIG.
When the roller shaft 38a of the sheet feeding roller 38 provided in the pulley 61 of the first drive unit 42 rotates in the counterclockwise arrow C direction, the clutch 44 is fixed in the lock direction and the pulley 61 rotates in the same direction. It

The one-way clutch 45 includes the second drive unit 4
When the roller shaft 40a of the registration roller 40 provided in the pulley 64 of No. 3 rotates in the counterclockwise arrow D direction,
The clutch 45 is fixed in the lock direction, and the pulley 64 is rotated in the same direction.

In FIG. 3, 67 is a paper detection switch.

In the above structure, when paper is fed from the storage cassette 36, when the copy switch is pressed, the first driving clutch 59 is engaged and the second driving clutch 60 is disengaged, and the driving force from the motor is changed by the gear mechanism. 41, and the driving force of the gear 58 causes the paper feed roller 38 to rotate in the direction of arrow C at a peripheral speed higher than the peripheral speed of the photoconductor 26.

Then, the one-way clutch 44 is fixed in the locking direction, and the rotation is transmitted to the pulley 61. Belt 6
The first pulley 62 of the transport roller 39 is rotated via
The transport roller 39 is driven at the same peripheral speed in synchronization with the paper feed roller 38.

At this time, the second pulley 65 is also rotated and the pulley 64 is rotated via the belt 66. However, since the one-way clutch 45 rotates in the free direction, the driving force is applied to the roller shaft 40a of the registration roller 40. Is not transmitted.

The paper feed roller 38 is used as the storage cassette 3
The uppermost sheet in 6 is pushed out, the sheet is fed in the direction of arrow E, passes through the sheet guide 46, and is transported to the registration roller 40 side by the transport roller 39.

The sheet of paper that has passed through the transport guide plate 47 from the transport roller 39 comes into contact with the paper detection switch 67 disposed on the front side of the registration roller 40. Then, the paper detection switch 67 is turned on, the first drive clutch 59 is disengaged, the paper feed roller 38 and the transport roller 39 are stopped, and the paper is temporarily stopped in a state in which the paper is caught in the registration rollers 40.

Then, the second drive clutch 60 is engaged and the first drive clutch 59 is disengaged in synchronization with the rotation timing of the photoconductor 26, and the driving force of the gear 52 causes the peripheral speed of the photoconductor 26 to be the same. The registration roller 40 is rotated in the direction of arrow D at the peripheral speed.

Then, the one-way clutch 45 is fixed in the locking direction, and the rotation is transmitted to the pulley 64. Belt 6
The second pulley 65 of the transport roller 39 rotates via 6,
The transport roller 3 is synchronized with the registration roller 40 at the same peripheral speed.
9 is driven.

At this time, the first pulley 62 is also rotated, and the pulley 61 is rotated via the belt 63. However, since the one-way clutch 44 is rotated in the free direction, the paper feed roller 3 is rotated.
No driving force is transmitted to the roller shaft 38a of No. 8.

The sheet conveyed in the direction of arrow F by the registration roller 40 and the conveying roller 39 is sent to the photoconductor 26 and an image is formed on the sheet. The above operation is repeated a predetermined number of times.

As described above, since the first and second drive units 42 and 43 having the one-way clutches 44 and 45 are provided, the paper feed roller 38, the transport roller 39, and the registration roller 40 are formed by a simple mechanism. And the transport roller 39 can be driven in synchronization with each other, and the peripheral speed when the paper feed roller 38 and the transport roller 39 rotate can be made faster than the peripheral speed when the registration roller 40 and the transport roller 39 rotate.
Since the conveyance speed to the registration roller 40 is increased, the first copy can be realized.

Further, since a complicated speed change mechanism as in the prior art is not required and the mechanism in the apparatus is simplified, a significant cost reduction can be realized.

Further, since the control signal to the clutch is simplified, the reliability of the sheet feeding device is improved.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, in this embodiment, a mechanism in which pulleys and belts are combined with the first and second drive parts 42 and 43 is used, but a mechanism in which gears and the like are combined may be used.

[0047]

As is apparent from the above description, according to the present invention, the first and second driving portions having the one-way clutch drive the conveying roller in synchronization with the feeding roller when the feeding roller rotates. In addition, since the transport roller is driven in synchronization with the registration roller when the registration roller rotates, the peripheral speed when the paper feed roller and the transport roller rotate is faster than the peripheral speed when the registration roller and the transport roller rotate with a simple mechanism. It is possible to speed up. Therefore, the conveyance speed to the registration rollers becomes faster, and the first copy can be realized.

Further, since a complicated speed change mechanism as in the prior art is not necessary and the mechanism in the apparatus is simplified, a significant cost reduction can be realized.

Further, as compared with the conventional case, the shift clutch can be eliminated, so that the control signal to the clutch is simplified and the reliability of the sheet feeding device is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a sheet feeding device showing an embodiment of the present invention.

FIG. 2 is a side view of the sheet feeding device of the present invention.

[Fig. 3] Overall configuration diagram of a copying machine

FIG. 4 is a configuration diagram of a conventional paper feeding device.

[Explanation of symbols]

 26 Photoreceptor 36 Paper Storage Section 37 Conveying Path 38 Feeding Roller 39 Conveying Roller 40 Registration Roller 42 First Driving Section 43 Second Driving Section 44,45 One-way Clutch

Claims (1)

[Claims] 1. A paper feeding device, wherein a paper feeding roller, a carrying roller, and a registration roller are provided in a carrying path for carrying paper from a paper storage unit to a photoconductor, and paper is fed when the paper feeding roller is rotated. A first drive unit that drives the transport roller in synchronization with the roller and a second drive unit that drives the transport roller in synchronization with the registration roller when the registration roller rotates are provided. The one-way clutch that does not transmit the driving force from the registration roller transmitted through the driving unit to the paper feeding roller is provided, and the second driving unit transmits the driving force from the paper feeding roller transmitted through the first driving unit. A sheet feeding device having a one-way clutch that does not transmit to a registration roller.