JP2566496Y2 - Sheet feeding device - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a separating means comprising, for example, a feeding rotating body for feeding a sheet and a separating rotating body for rotating and feeding back the second and subsequent sheets upstream while rotatingly contacting the feeding rotating body. The present invention relates to a sheet feeding apparatus in which a leading end of a separated sheet is nipped and a rear portion of the sheet is sandwiched by the separating means so as to take a sheet feeding timing, and relates to image processing such as a copying machine, an image reader, and a facsimile. It is used to feed a document to a platen of the apparatus, or to feed a sheet for image formation.

[0002]

2. Description of the Related Art The structure of a conventional sheet feeding apparatus is shown in FIG.

As shown in the figure, a sheet feeding apparatus 1 includes a feeding roller 4 serving as a feeding rotating body on an upstream side along a sheet feeding path 2.
And a registration roller pair 6 including a pair of roller groups provided on the downstream side of the feeding path 2.

The feed roller 4 of the separating / feeding means 3 rotates in a direction for feeding the sheet, and the separation belt 5 rotates in a direction for stopping the sheet.

[0005] As for a plurality of sheets sent along the sheet feeding path 2, only one sheet in contact with the feeding roller 4 is sent by the separation feeding means 3, and the other sheets are separated by the separation belt 5.
Is pushed back upstream.

The leading end of the separated sheet is abutted against the pair of registration rollers 6, and the operation of the separation feeding means 3 is stopped when a slightly curved shape, that is, a registration loop is drawn as shown in the figure. I do. It is well known that the feeding posture is correctly corrected by drawing the above loop.

[0007] The registration roller pair 6 is started at the feeding timing, and the one sheet is fed. At this time, conventionally, the separation feeding means 3 is in a non-driving state, and the separation belt does not rotate. However, a one-way clutch is provided inside the feeding roller 4 so that the feeding roller 4 rotates with the sheet pulled out by the registration roller pair 6. This is because if the rotation of the feed roller 4 is stopped, the reverse pulling force on the sheet being pulled by the registration roller pair 6 becomes too strong, and the sheet feeding attitude is disturbed, or the slippage occurs at the registration roller pair 6. This causes the feeding timing to be out of order.

[0008]

However, since the separation belt 5 does not rotate at all while the sheet is being pulled out, the second sheet near the contact point between the separation belt 5 and the feeding roller 4 has the above-mentioned structure. There is a problem that the sheet is so-called dragged (or continuously fed) with one sheet (hereinafter, referred to as a first sheet or a preceding sheet). (Note that the term “double feed or double feed” is a term similar to continuous feed or double feed, but in the present specification, hereinafter, the above-described event in which a sheet is dragged to another sheet and fed is referred to as continuous feed. In the viewpoint of the entire apparatus, the feeding of a plurality of sheets including the continuous feeding from the viewpoint of the entire apparatus is referred to as a double feed or the like. Accordingly, it is an object of the present invention to obtain a sheet feeding apparatus without double feed when a sheet following the sheet is pulled out from the separating / feeding means without being taken along from the separating / feeding means.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to rotate a feeding rotating body in a conveying direction by a pulling force when pulling a rear portion of a sheet from a separating feeding means by a feeding means. By this rotation, a rotational force transmitting means for rotating the separation rotator in a direction opposite to the sheet conveying direction is provided between the feeding rotator and the separation rotator.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, as an embodiment to which the sheet feeding apparatus of the present invention is applied, a document feeding apparatus for feeding a document to an image forming apparatus such as a copying machine will be described.

<Construction> As shown in FIG. 1, a document feeder 10 includes a document tray 11 on which a document is placed, and a document from the document tray 11.
A sheet feeding unit 20 for separating and feeding a sheet, and a document received from the sheet feeding unit 20 and conveyed to the platen P of the image forming apparatus C.
The transport unit 50 is configured to stop above and receive an exposure process, a discharge unit 60 for discharging an exposed document, a discharge tray 12 for stacking the discharged documents, a control device (not shown), and the like. .

The sheet feeding apparatus according to the present invention is applied to the sheet feeding section 20, and the sheet feeding apparatus is hereinafter referred to as the sheet feeding section 20.
It will be described by reading as follows.

The paper feed unit 20, the transport unit 50, and the paper discharge unit 60 are driven by a first drive motor M1.
Separately, it is configured to be driven by the second drive motor M2, respectively.

The first drive motor M1 drives a non-circular half-moon roller 22 or a feeding rotating body, for example, a feeding roller 24, which is a feeding means at the time of forward rotation, and drives a registration roller 29 or a transporting unit 50 by reverse rotation. It is.

As shown in FIG. 1, the paper feed unit 20
Following the downstream end of the sheet feeding unit 1, a sheet feeding path 21 having guides 21 a and 21 b that extend to the entrance of the conveying unit 50 and guide the document is provided. A half-moon roller 22 serving as a feeding unit is provided below the uppermost stream side of the paper feed path 21.

The half-moon roller 22 contacts the lowest one of the originals on the original tray 11 and tries to feed it out. In the home position (HP), the notch faces upward and retreats from the paper feed path 21. doing.

A stopper 23 is provided between the half-moon rollers 22 so as to penetrate through the guide 21a and be able to come and go.

Next, a feed roller 24, which is a feed rotator, is provided downstream along the sheet feed path 21.

Further, above the feed roller 24,
Separating rotator 2 composed of a pair of rollers 26 and 27 and a separation belt 28 stretched over the pair of rollers 26 and 27
5 are provided. The rollers 26 and 27 each have a shaft 2
6a and 27a, the shaft 26a of which is a drive shaft, which acts to push back other than the lowest document to the upstream side.

It should be noted that the feed roller 24, which is a feed rotating body,
And the separating rotator 25 constitute a separating and feeding means.

An empty sensor ETS for detecting the presence or absence of a document is provided between the half-moon roller 22 and the separation rotating body 25.

The paper feed path 21 is curved, and faces the entrance of the transport section 50 with the original reversed. Conveyance means for catching the leading end of the document near the curved portion, adjusting the posture, and measuring sheet feeding timing, for example, registration rollers 29 and 30
Is provided, and a registration sensor 31 for detecting a paper feed timing of a fed document is provided.

The transport section 50 is provided on the side plate of the document feeding apparatus 10.
A pair of belt rollers 51 and 52 are pivotally supported, a transport belt 53 is stretched around these belt rollers 51 and 52, and a plurality of press rollers 54 are provided.

The paper discharge section 60 is greatly curved from the exit of the transport section 50 and guides 61a for reversing the original by approximately 180 degrees.
A paper discharge path 61 having 61b is provided. A pull-out roller 62, a pinch roller 62a, and a paper discharge sensor 63 are provided from a position near the transport unit 50 along the paper discharge path 61, and paper discharge rollers 65a, 65b are provided near the discharge port 64. I have.

Next, a control device (not shown) receives signals from the empty sensor ETS, the registration sensor 42, the paper ejection sensor 63, and the like, and performs a predetermined calculation. The calculation result and various commands from the image forming apparatus C are executed. The CPU includes a CPU that controls the driving of each of the drive motors M1, M2, and the like in a timely manner based on the signal, and transmits a control result and the like to the image forming apparatus C.

Referring to FIG. 2, a drive system centering on the paper feed unit 20, in particular, a drive system around the feed roller 24 and the separation rotary body 25 as a feed rotary body will be described in detail.

The drive system of the paper feed unit 20 belongs to the system of the first drive motor M1 as shown in the figure, and the output of the motor M1 is supplied from an output pulley 101 connected to an output shaft to the timing belt 1.
02, and transmitted to the coaxial gear 105 via the pulley 103.

From the gear 105, the gears 106, 10
It is transmitted to the gear 109 via 7, 108. The gear 109 is connected to the shaft 24a of the feed roller 24 via a one-way clutch (hereinafter abbreviated as OW).

The gear 109 is also connected via an intermediate gear 110 to the shaft 22a of the meniscus roller 22 via an OW.

On the other hand, the shaft 24a of the feed roller 24 has a gear 112 fixedly connected to the other end thereof, and the gear 112 is connected to the roller 26 on the driving side of the separation rotating body 25 via an intermediate gear 113.
With the gear 114 connected to the shaft 26a.

The gear 105 is connected to the shaft 105a via an OW. The gear 105 is connected to the shaft 51a via a pulley 120, a timing belt 121, and a pulley 122 provided at the other end of the shaft 105a. Power is transmitted to 51.

The gear 1 also connected to the shaft 51a
23, through the intermediate gear 124, the registration rollers 2
9 in cooperation with the gear 125 of the shaft 29a. In addition, axis 2
9a is provided with an electromagnetic clutch 126 for appropriately engaging and disengaging the shaft 29a and the gear 125.

<Operation> The operation of the embodiment will be described below based on the above configuration.

When the power is turned on, the home position sensor HPS checks whether or not the half-moon roller 22 has reached the initial position (home position HP). The home position sensor HPS is ON and the drive motor M1 stops. , Initialization is completed.

After the initialization is performed, when an original is placed on the original tray 11, the empty sensor ETS is turned on, and the preparation for sheet feeding is completed.

Here, when a paper feed signal is received from the image forming apparatus C side, the paper feed operation starts, and the first drive motor M1 rotates forward.

The forward rotation of the motor M1 causes the half-moon roller 22 to rotate.
Is fed out by the feed roller 24, and the second and lower sheets are pushed back upward by the separation belt 28. As shown in FIG. 2, during the above operation, power is not transmitted to the registration roller 29 and the transport unit 50 by the OW of the shaft 105a.

The fed document is detected by the registration sensor 31, and after a short time, the motor M1 is stopped, and the leading end of the document is registered with the registration roller 2 which is a pair of registration rollers.
The resist operation is completed in a state where a bite is made between 9 and 30 and a slight resist loop is drawn on the rear part.

After a short time after the completion of the registration, the motor M1 rotates in the reverse direction. The power is transmitted to the belt roller 51 and the registration roller 29 by this reverse rotation. On the other hand, due to the action of OW, the driving force is increased by the half-moon roller 22,
It is not transmitted to the separation roller 26, the feeding roller 24, etc.
Each of these rollers remains stopped.

By the way, when the original is fed by the rotation of the registration roller 29 as described above, when the feeding roller 24 and the separation rotating body 25 constituting the separation feeding means are in a stopped state, it is formed. When the registration loop is resolved, the original (previous original or first original) is strongly pulled so as to rotate the feeding roller 24 in the feeding direction.

On the other hand, the number of originals fed out by the half-moon roller 22 and sent to the separation rotary member 25 is usually a plurality of sheets, and the originals tend to be output downstream following the operation of extracting the preceding original.

However, as shown in FIG.
4 is released from the connection with the drive motor side by the OW provided between the shaft 24a and the gear 109, so that the shaft 4a can smoothly rotate and rotate the shaft 24a as it is via the gears 112, 113, 114. And transmitted from the roller 26 to the separation belt 28. Thus, the second and subsequent originals are always subjected to the separating operation even during the operation of pulling out the first original, and are not fed together.

The document thus sent is localized at the reference position P1 of the platen P, and the image forming apparatus C performs a copying operation (exposure) here.

The completed document is discharged again from the platen P by the reverse rotation of the motor M1, and subsequently discharged to the discharge tray 12 by the driving of the motor M2.

In the document feeder 10, the motor M1 rotates forward for the advance operation of the second document (second document) during the above-mentioned exposure operation, and the second document is fed out during this time. It is advanced by the registration roller 29 and waits.

<Effects of the Embodiment> According to this embodiment, the separation feeding means including the feeding roller 24 for feeding the sheet and the separation rotating body 25 for feeding the second and lower sheets backward to the upstream side, Downstream of the feeding means,
In addition to the registration rollers 29 and 30 for nipping the leading end of the separated sheet and setting the sheet feeding timing, when the registration rollers 29 and 30 are operated, the separation feeding unit is not driven and the separation feeding unit is not driven. In a sheet feeding apparatus in which a rear portion of a sheet is pinched by feeding means and pulled out by registration rollers 29 and 30,
When the trailing end of the sheet is pulled out of the separation feeding means by the operation of the registration rollers 29 and 30, the feeding roller 24 is rotated in the feeding direction by the pulling force, and the separation rotator 25 is rotated by this rotation. Since the rotational force transmitting means for rotating in the reverse feeding direction is provided between the feeding roller 24 and the separation rotating body 25, when the feeding roller 24 rotates with the sheet extracting operation, the separation feeding means is provided. The other sheet that has been fed is pushed back to the upstream side by the separating rotator 25, and the next sheet is fed along with the sheet that is being pulled out even if the driving of the separating / feeding unit is stopped. No double feed can be prevented.

<Modifications> The present invention is not limited to the above embodiment, and for example, the following modifications are possible.

In the above embodiment, the registration rollers 29, 30
Has been described, the registration of the leading end of the sheet is performed, but a device that conveys the sheet separated by the separating and feeding unit by the transfer unit without correcting the registration may be used.

[0049]

According to the sheet feeding apparatus of the present invention, a driving means capable of normal and reverse rotation, a feeding rotating body which is driven to rotate in the sheet conveying direction by the driving means and feeds out a contacting sheet, and this feeding means A separating / feeding unit having a separating / rotating body that is provided in contact with the rotating body, and is rotatably driven in a direction opposite to the sheet conveying direction and prevents the conveyance of the sheet following the sheet fed by the feeding rotating body; Transport means for transporting the sheet separated and fed by the separating / feeding means while pulling out the separating / feeding means sandwiching the rear portion of the sheet when the driving of the separating / feeding means is stopped. , A driving force transmitting means for transmitting only the forward rotation of the driving means is interposed between the driving means and the feeding rotating body, and the rear part of the sheet is pulled from the separating and feeding means by the conveying means. The rotation of the feed rotator in the transport direction is performed by the pulling force of the feed rotator. And at a position that can follow the rotation of the feed rotator, whose driving force is regulated by the driving force transmitting means. While using only one driving force transmission means, the reverse rotation drive control of the separation rotating body at the time of switching between the feeding and transporting drive follows the rotation of the feeding rotating body without special control and performs with good timing. When the rear part of the sheet is pulled out of the separation / feeding means by the feeding means, by rotating the feeding rotating body in the feeding direction along with the pulling operation,
The rotating force is transmitted to the separation rotating body via the rotating force transmitting means, and the separating rotating body rotates in a direction opposite to the sheet conveying direction, so that the other sheets held in the separation feeding means are separated and rotated. The sheet is prevented from being conveyed by the body, and even if the driving of the feeding rotating body and the separating rotating body is stopped, the next sheet is not fed along with the sheet being pulled out, and double feeding can be prevented.

[0050]

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a document feeder to which a sheet feeder of the present invention is applied.

FIG. 2 is a power transmission system diagram centered on a paper feeding unit.

FIG. 3 is an explanatory view of a main part of a conventional sheet feeding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Document feeder 20 Paper feeder (sheet feeder) 24 Feeding roller (feeding rotary body) (separation feeding means) 24a Shaft (power transmission means) 25 Separating rotary body (separating feeding means) 28 separation Belt (separated rotating body) 29 Registration roller (registration roller pair) 30 Registration roller (registration roller pair) 112 Gear (power transmission means) 113 Gear (power transmission means) 114 Gear (power transmission means) 26a Shaft (power transmission means)

Claims (2)

(57) [Scope of request for utility model registration] 1. A driving means capable of rotating forward and backward, and the driving means
A feed rotator that is driven to rotate and feeds a sheet in contact with the sheet transport direction, and is provided in contact with the feed rotator, and is driven to rotate in a direction opposite to the sheet transport direction and fed by the feed rotator. Separation feeding means having a separation rotating body that prevents conveyance of the sheet following the sheet to be fed,
Sheet feeding means for feeding the sheet separated and fed by the separation feeding means while pulling out the sheet from the separation feeding means sandwiching the rear portion of the sheet while the driving of the separation feeding means is stopped. In the feeding device, the driving
Between the feeding means and the feeding rotating body,
Only the driving force transmitting means for transmitting only the power, and rotating the feeding rotary body in the transport direction by a pulling force at the time of pulling out the rear portion of the sheet from the separation feeding means by the transporting means, by this rotation, A rotational force transmitting means for rotating the separation rotating body in a direction opposite to the sheet conveying direction, between the feeding rotating body and the separation rotating body ,
Moreover, the driving force is regulated by the driving force transmitting means.
A sheet feeding device provided at a position capable of following the rotation of a feeding rotating body . 2. The registration roller, wherein the conveying means regulates the leading end of the sheet separated by the separating / feeding means to form a bend in the sheet, and then conveys the sheet while pulling out the rear end of the sheet from the separating / feeding means. A sheet feeding device comprising a pair.