JP2905673B2 - Paper transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, for example, in a paper transporting apparatus of a copying machine, when a paper is transported from a storage section to a photoreceptor, a paper feed roller and a transport roller are rotated and transported to a registration roller. Then, stop the rotation of the feed roller and the transport roller,
Next, the registration roller and the conveyance roller are rotated in accordance with the rotation timing of the photoconductor, and the paper is conveyed to the photoconductor. At this time, each roller was rotating at the same peripheral speed via a gear and a clutch by the driving force from the motor.

Recently, in order to support first copy,
The paper feed speed also needs to be increased, but since the peripheral speed of each roller is rotated in accordance with the peripheral speed of the photoconductor, the copy speed cannot be increased to a certain level or more.

Therefore, a method has been adopted in which the speed is increased only when the sheet feeding roller and the conveying roller are rotated.
In this method, since the peripheral speed of the paper feed roller is rotated faster than the peripheral speed of the registration roller, a speed change mechanism that changes the peripheral speed of the transport roller in accordance with each peripheral speed is provided in the transport roller. . In the paper transport apparatus provided with this speed change mechanism, as shown in FIG.
, Through each gear 2, 3, 4, 5, 6
This is transmitted to the conveyance roller 8 and the registration roller 9.

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

At this time, the transmission clutch 1 of the transmission 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 integrally formed with the shaft 8a of the transport roller 8 is rotated by the gear 13,
The transport roller 8 rotates. Since the gears 6 and 14 are set to the same gear ratio, the peripheral speeds of the feed roller 7 and the transport roller 8 are the same, and the rotation causes the paper to move in the directions indicated by arrows A and B.
Conveyed in the direction.

Next, when the drive clutch 15 is engaged to rotate the registration roller 9, the rotation of the gear 2 drives the registration roller 9. At this time, the rotation of the gear 4 is transmitted to the transport roller 8 by simultaneously engaging the transmission clutch 16. The peripheral speeds of the registration roller 9 and the conveyance roller 8 are made equal by the gears 2 and 4 set to the same gear ratio.

[0008]

However, as shown in FIG. 6, since the feed roller 7 and the transport roller 8 rotate synchronously, the distance from the feed roller 7 to the registration roller 8 is smaller than the minimum sheet size. If it is long, there is a problem that the second sheet is fed next.

Further, since the peripheral speed of the conveying roller 8 is adjusted to the peripheral speed of the paper feed roller 7 and the registration roller 9, a transmission mechanism 11 in which a clutch and a gear are combined is required. Cost was up. Further, the drive clutches 10 and 15 and the speed change clutches 12 and
16 have to be operated almost simultaneously, the combination of the operation timing signals of the drive clutches 10, 15 and the shift clutches 12, 16 becomes complicated, and there is a problem that the reliability is greatly reduced.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a paper transporting apparatus which can easily switch the driving of each roller with a simple structure.

[0011]

In order to solve the above-mentioned problems, a paper transport device used in an image forming apparatus according to the present invention supplies a paper to a transport path for transporting a paper from a paper storage unit to a photosensitive member. paper roller, the sheet conveying device having a conveying roller and a registration roller, the registration straws
Provided at one end of the rotating shaft of the
And a registration gear meshing with the gear of the drive source,
It is installed at one end of the rotation shaft of the feed roller via a transfer clutch.
Peripheral speed of the registration roller connected to the registration gear
Transport gear that rotates the transport roller at a higher peripheral speed
And a paper feed clutch at one end of the rotation shaft of the paper feed roller.
And is connected to the transfer gear and is connected to the transfer roller.
A feed gear that rotates the feed roller at the same peripheral speed as the peripheral speed
A first drive unit comprising: a rotation shaft of the registration roller;
A pulley provided on the other end side and a rotating shaft of the transport roller;
At the other end of the
Transport rollers at the same peripheral speed as the peripheral speed of the registration rollers.
Second drive consisting of a pulley with clutch for rotating
And a unit .

[0012]

According to the paper transport apparatus of the present invention, as described above, the transport roller can be driven by the first drive unit and the second drive unit. The speed of the sheet to be fed can be set faster than the speed of the sheet to be transferred between the transport roller and the registration roller, and the driving of the registration roller and the transport roller are completely synchronized.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet conveying apparatus according to an embodiment of the present invention.

As shown in FIG. 5, the copying machine of this embodiment
An original cover 21 is provided on the upper part of the copying machine main body 20, an original table 22 is arranged on the lower surface of the original cover 21, light is irradiated on an original on the original table 22 by a lamp 23, and the reflected light is reflected by a mirror 24a. To 24f, an optical system 27 for exposing the photosensitive member 26 via the lens 25, a developing device 28 disposed around the photosensitive member 26, a transfer device 29, a cleaning device 30, a charging device 31, Fixing device 32 for fixing toner on paper transferred by photoreceptor 26
And a discharge roller 33 for discharging a sheet from the fixing device 32.
And a paper discharge tray 34 for receiving discharged paper, and a paper feeding device 35 for feeding paper to the photoreceptor 26.

The paper feeder 35 includes a storage cassette 36 for storing paper, and a transport section 37 for transporting the paper from the storage cassette 36 to the photosensitive member 26. The transport section 37 has an upstream in the paper transport direction. A paper feed roller 38 for sequentially feeding the paper in the storage cassette 36 from the top to the downstream, a transport roller 39 for feeding the paper fed by the paper feed roller 38 to the downstream side, and a transport roller A registration roller 40 is provided for temporarily stopping the sheet sent from 39 before the photosensitive member 26 and sending the sheet to the photosensitive member 26 in synchronization with the rotation timing of the photosensitive member 26.

Next, as shown in FIG. 1, a driving force from a motor (not shown) is transmitted to the paper feed roller 38 and the transport roller 39 via a drive input gear 41 and a gear mechanism 42.

Rotary shaft 4 fitted with a pair of paper feed rollers 38
3. A rotating shaft 44 fitted with a pair of transport rollers 39 and a rotating shaft 45 fitted with a pair of registration rollers 40 are arranged side by side on bearings 47, 48 and 49 provided on a plate 46 at a required interval. You. Further, the rotating shafts 43, 4
Paper feed gears 51 are fitted to the rear frames 4 and 45 via a paper feed clutch 50, respectively, a transport gear 53 is fitted via a transport clutch 52, and a resist clutch 54. The registration gear 55 is fitted.

An idler gear 57 pivotally mounted on a shaft 56 provided on the plate 46 between the feed gear 51 and the transport gear 53 is engaged with the idler gear 57, and is provided on the plate 46 between the transport gear 53 and the resist gear 55. An idler gear 59 pivotally mounted on the shaft 58 is engaged.

A pulley 60 with a built-in one-way clutch is fitted on the front frame side of the rotating shaft 44,
A pulley 61 is fitted on the front frame side of the rotating shaft 45, and a timing belt 62 is suspended between the pulley 60 with clutch and the pulley 61. Further, a paper detection sensor 63 is disposed on the upstream side adjacent to the transport roller 39 or the rotation shaft 44, and the paper detection sensor 64 is disposed on the upstream side adjacent to the registration roller 40 or the rotation shaft 45.

The drive input gear 41, each gear 51, 5
3, 55, 57 and 59, rollers 38, 39 and 40
In the copying machine shown in FIG. 5, it is not located on a straight line due to the shape of the conveying path 37, but the meshing state of the gears is shown in FIG.
The state of the suspension of the paper feed roller 38, the transport roller 39, the registration roller 40, the pulleys 60 and 61, and the timing belt 62 is as shown in FIG. In FIG. 3, reference numeral 65 denotes a one-way clutch built in the pulley 60.

The transport roller 39 is driven by a drive input gear 41, a registration roller gear 55, an idler gear 59, a transport gear 53, a first drive unit driven via a transport clutch 52, and a drive input gear. 41, registration roller gear 55, registration clutch 54, rotating shaft 45,
This is performed by a second driving unit driven via a pulley 61, a timing belt 62 and a pulley 60 with a one-way clutch 63.

In this apparatus having the above-described configuration, when the copy switch is turned on in a copying machine that is turned on, the driving force of the driving input gear 41 linked with the motor is sequentially changed to the registration roller gear. 55, the idler gear 59, the transport gear 53, the idler gear 57, and the paper feed gear 51, and at that time, the paper feed clutch 5
The signal (a) shown in FIG. 4 is input to the feed clutch 0, the paper feed clutch 50 is connected to the paper feed gear 51, and the signal (b) is also input to the transport clutch 52. Is connected to the transport gear 53, the paper feed roller 38 is rotated, and the uppermost sheet of the storage cassette 36 is guided in the direction A in the curved guide 37a in a substantially U-shape. The sensor 63 detects the sheet at the timing of the signal (d) at the stage when the sheet reaches and is clamped at 39, the signal (a) to the sheet feeding clutch 50 is stopped, and the sheet feeding clutch 50 is released to feed the sheet. The rotation of the paper roller 38 is stopped.

Subsequently, the paper is guided in the direction B downstream on the transport guide plate 37b by the rotation of the transport roller 39 by the driving force of the first drive unit, and the leading end of the paper reaches the registration roller 40 and is bent. At the stage where the transfer clutch 52 is made, the sensor 64 detects the sheet at the timing of the signal (e), and the signal (b) to the transfer clutch 52 is stopped.
Is released, and the rotation of the transport roller 39 is stopped. At this time, since the one-way clutch 65 is built in the pulley 60 fitted on the rotation shaft 44 of the transport roller 39,
Despite the rotational driving of the transport roller 39, the driving force is not transmitted to the registration roller 40 via the timing belt 62 and the pulley 61, and the registration roller 40 remains stopped.

Next, the signal (c) shown in FIG.
Is connected to the registration gear 55 to rotate the registration roller 40, and the driving force of the drive input gear 41 is transmitted to the transport roller via the rotation shaft 45, the pulley 61, the timing belt 62, and the second drive unit of the pulley 60. Therefore, the transport roller 39 and the registration roller 40 are rotated and driven in synchronization with each other, the sheet is transported in the direction C, that is, in the direction of the photoconductor 29, and the sensor 64 detects the trailing edge of the sheet and detects the registration clutch 54. Is released from the registration gear 55, and the rotation of the conveyance roller 39 and the registration roller 40 is stopped.

[0025]

According to the present invention, there is provided a paper conveying apparatus comprising a registration row.
When the paper is fed to the roller, the registration gear of the first drive unit
Rotated by the drive source due to the relationship with the transport gear
The transport roller and the peripheral speed are faster than the peripheral speed of the registration roller.
The paper feed roller can be rotated,
When the paper is fed to the photosensitive member by the
Register the roller at a lower peripheral speed than when feeding paper to the
Rollers and transport rollers can be rotated,
Simple drive source control without changing the number of turns
The transport speed can be changed in two stages.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a sheet conveying device according to an embodiment of the present invention.

FIG. 2 is a side view showing a relationship between a gear and a roller of a first driving unit in the present apparatus.

FIG. 3 is a side view illustrating a relationship between a pulley, a roller, and the like of a second driving unit in the apparatus.

FIG. 4 is a timing chart of an operation state of a roller and a sensor in the present apparatus.

FIG. 5 is a schematic side view of a copier embodying the present apparatus.

FIG. 6 is a configuration diagram of a conventional paper transport device.

[Explanation of symbols]

 1,41 Drive input gear 2,4,6,55,53,51 Gear 3,5,59,57 Idler gear 7,38 Feed roller 8,39 Transport roller 9,40 Registration roller 10,12,16,15 , 50, 52, 54 Clutch 60, 61 Pulley 62 Timing gear 63, 64 Sensor

Claims (1)

(57) [Claims] In a paper transport apparatus having a paper feed roller, a transport roller, and a registration roller in a transport path for transporting a sheet from a paper storage unit to a photoconductor, a registration roller is provided at one end of a rotation shaft of the registration roller.
That is provided through a switch and meshes with the drive source gear
Gear and one end of the rotating shaft of the transfer roller via a transfer clutch.
The registration roller is connected to the registration gear
For transport that rotates the transport roller at a peripheral speed higher than the peripheral speed of
A gear and a paper feed clutch are connected to one end of the rotation shaft of the paper feed roller.
Peripheral speed of the transport roller connected to the transport gear
From the paper feed gear that rotates the paper feed roller at the same peripheral speed as
And a pull-up provided on the other end of the rotation shaft of the registration roller.
And a pulley provided on the other end of the rotating shaft of the transport roller.
Connected via a timing belt
With a clutch that rotates the transport roller at the same peripheral speed as
And a second driving section comprising a second driving section .