JP2001335174A - Paper separating feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding separating device capable of preventing the occurrence of a double feed and nonfeed when sending out the uppermost part paper by a paper feed roller. SOLUTION: An additional roller 14 having the rotational direction inverse to the rotational direction of the paper feed roller 1 and faster in the abutting finish timing to a sheet-like medium of the uppermost part than the abutting finish timing of the paper feed roller, is arranged between a separating claw 3 and the paper feeding roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separation sheet feeder and an image forming apparatus for separating and feeding one sheet medium from a stacked sheet medium.

[0002]

2. Description of the Related Art In a paper feeding system of an image forming apparatus using an electrophotographic method, an electrostatographic method, or the like, a sheet medium (hereinafter, referred to as a sheet) contained in a sheet cassette is placed on the uppermost sheet. There is a so-called corner claw separation method that uses a paper feed roller that abuts and feeds paper and a separation claw that is provided at a corner of the front edge of the paper feed cassette and separates paper. Hereinafter, a basic configuration of a corner claw separation system, which is a conventional paper feeding system, will be described with reference to FIGS.

In FIG. 14, in a paper feed cassette 5,
The sheet-like sheet 2 to be used for the transfer is accommodated by the extensible coil spring 8 via the bottom plate 60, the leading end of which is abutted against the separation claw 3 provided at the corner of the front edge of the sheet cassette 5. I have.

When the paper 2 is separated from the paper feed cassette 5 and fed, first, the paper feed roller 1, which is opposed to the facing portion of the paper feed roller spring 8, feeds the paper in the paper feed cassette 5. 2 is brought into contact with the uppermost sheet 2a disposed on the uppermost part of the sheet 2.

When the paper feed roller 1 is rotated in the clockwise direction 6 in this state, the leading end of the uppermost sheet 2a comes into contact with the separating claw 3, and the uppermost sheet 2a is brought into contact with the contact force by the separating claw 3 and the paper. Due to the stiffness of the paper and the contact force of the paper feed roller 1, the shape is bent between the paper feed roller 1 and the separation claw 3, and at the same time, a bending force is generated, and the paper is lifted upward. Separated from paper 2.

Thereafter, when the sheet feeding roller 1 is further rotated in the clockwise direction 6, the uppermost sheet 2a is moved between the sheet feeding roller 1 and the separation claw 3 into an upwardly convex shape 9a shown in FIG.
As a result, the bending force greatly increases, and at the same time, the bending force further increases.

When the bending force is equal to or less than the contact force of the sheet feeding roller 1 and exceeds the contact force of the separation claw 3 generated at the leading end of the uppermost sheet 2a, the sheet feeding roller 1 is brought into contact with the uppermost sheet 2a. Due to the contact, the transport force is changed from the paper feed roller 1 toward the transport rollers 4a and 4b, that is, the transport force in the transport direction and the upward repulsive force received from the paper 2, and the leading edge of the uppermost paper 2a. A flip force 10 in the direction indicated by reference numeral 10 in FIG.

For this reason, the leading end of the sheet 2 jumps over the projecting portion of the separation claw 3 and jumps out of the sheet feeding cassette 5, and travels from the sheet feeding cassette 5 to the transport rollers 4a and 4b. The shape of the leading end of the sheet at this time is indicated by reference numeral 9b in FIG. Further, due to inertia, the leading end of the sheet is sent out to the transport rollers 4a and 4b.

Thereafter, the uppermost sheet 2a is transported by the transport rollers 4
a, 4b, these transport rollers 4a,
Transported by rotation in the directions of arrows 6 and 7 in 4b,
At the same time, the contact of the paper feed roller 1 with the uppermost paper 2a is released, so that the uppermost paper 2a is fed out of the paper feed cassette 5.

However, in these paper feeding systems, when the uppermost paper 2a is sent out by the paper feed roller 1 ', the uppermost paper 2a in a high sticking state or a high frictional state and other upper papers 2a due to variations in paper characteristics. Even when the paper 2 is stuck and the separation claw 3 is provided, there is a case where only one top sheet 2a cannot be peeled from the paper 2.

In this case, a double feed in which several sheets of other sheets 2 are simultaneously conveyed together with the uppermost sheet 2a, or a non-feed in which the uppermost sheet 2a itself is not conveyed occurs. In particular, when the paper is fed at a high speed, the above-described problem becomes conspicuous.

Japanese Patent Application Laid-Open No. Hei 9-110198 discloses a known technique in which a single paper feed roller is provided and a mechanism for rotating the paper feed roller in a forward or reverse direction is provided.
There is a "paper feeding method for paper in a cassette" disclosed in Japanese Patent Application Laid-Open Publication No. HEI 9-303, 1988. According to this known invention, the uppermost sheet is deflected by a sheet feeding roller having the above-described structure and rotated in the forward or reverse direction to separate it from other sheets.

[0013]

In the above-described paper feeding method, when the uppermost paper is fed out by the paper feed roller, the uppermost paper in a high sticking state or a high friction state and other upper paper due to variations in paper characteristics. Even when the sheet is stuck and has a separation claw, there is a case where only one uppermost sheet cannot be removed from the sheet.

In this case, there may occur a double feed in which several sheets of other sheets are simultaneously conveyed together with the top sheet, or a non-feed in which the top sheet itself is not conveyed. In particular, when the paper is fed at a high speed, it tends to appear remarkably.

[0015]

SUMMARY OF THE INVENTION The present invention has the following constitution in order to eliminate double feeding and non-feeding and to enhance separability. (1). By rotating the paper feed roller in contact with the uppermost sheet-like medium of the sheet-like medium stacked in the paper supply unit, the topmost sheet-like medium is sent out in the paper supply direction, and disposed at the leading end of the paper supply unit. In the separation sheet feeding device for separating and feeding the uppermost sheet-like medium from the other sheet-like media by the separated separation claw, the rotation direction is opposite to the rotation direction of the feed roller, and the uppermost sheet is The additional roller whose contact end time with the sheet medium is earlier than the contact end time of the paper feed roller is
One or a plurality thereof is provided between the separation claw and the paper feed roller (claim 1). (2). In the separation sheet feeding device according to (1), means for interlocking the driving of the additional roller with the driving of the sheet feeding roller is provided (claim 2). (3). (1) In the separation sheet feeding device described in (1) or (2), the projection of the separation claw in a direction perpendicular to the sheet medium conveyance direction is longer than the projection length of the separation claw in the sheet medium conveyance direction. One separation claw with a long shape,
Alternatively, it is provided with a plurality (claim 3). (4). (1) In the separation sheet feeding device according to any one of (1) to (3), the rotation axis direction of the additional roller and the direction from the additional roller to the separation claw are perpendicular to each other. One or more combinations,
(Claim 4). (5). (1) In the sheet separating apparatus described in any one of (1) to (3), while the uppermost sheet-shaped medium is in the sheet feeding unit, the rotation of the sheet feeding roller and the additional roller is positive and negative. It is repeated once or multiple times in the opposite direction (claim 5). (6). (5) The sheet feeding / separating apparatus according to (5), further comprising a detecting unit that detects that the sheet-shaped medium in the sheet feeding unit has been left for a predetermined period of time, and the detecting unit detects the sheet-like medium before feeding the sheet after a predetermined period of time has passed. The rotation of the paper feed roller and the additional roller is repeated once or plural times in the forward and reverse directions (claim 6). (7). An image forming apparatus having process means for charging, exposing, developing, and transferring, transferring an image of a photoreceptor onto a sheet-like medium sent from a sheet feeding unit, fixing the sheet, and discharging the sheet, wherein (1) to (6) ) Is provided (claim 7).

[0016]

Embodiments of the present invention will be described below. FIG. 1 shows an image forming apparatus to which the present invention is applied,
This is a so-called internal discharge type image forming apparatus that discharges recorded paper inside a box-shaped apparatus. An image forming unit 100 is disposed substantially at the center of the image forming apparatus. A sheet feeding unit 200 is disposed immediately below 100.

The paper feeding unit 200 has a system in which paper is directly placed along a guide member without a paper cassette and a system in which the paper cassette 5 is provided. In this example, a system including the paper feed cassette 5 is shown.

Although only one sheet feeding unit 200 is shown, another sheet feeding unit similar to the sheet feeding unit 200 can be added as necessary. Paper feeding from the additional paper feeding unit is performed via the transport path 400.

A manual sheet feeding table 47 for performing manual sheet feeding.
Reference numeral 0 is provided on the front right hand of the image forming apparatus so as to be freely opened and closed. The manual paper feed tray 470 is usually housed in the image forming apparatus main body, and is used by being rotated about a fulcrum 470J and displaced to a raised state as needed. Further, the auxiliary table 470a can be pulled out from the tip side of the table.

A document reading device 300 as document reading means for reading a document is provided above the image forming section 100 with a space S therebetween. Image forming unit 10
A discharge storage unit 410 is provided below the space S between the image reading apparatus 300 and the document reading apparatus 300, and discharges and stores an image-formed sheet.

The space S has a space (not shown) into which a hand can be inserted. The paper discharged to the discharge storage unit 410 can be taken out using this space.

The image forming unit 1 includes electrical units E and F for electrically driving and controlling the image forming apparatus.
Is arranged. Also, a drum-shaped photoconductor 500
Is arranged. Around the photoconductor 500, a charging device 600 that performs a charging process on the surface of the photoconductor 500, an exposure device 700 that irradiates image information to the surface of the photoconductor with laser light,
A developing device 800 for visualizing an electrostatic latent image formed by exposing the surface of the photoconductor 500, a transfer device 900 for transferring a toner image visualized on the photoconductor 500 to paper, and remaining on the photoconductor surface after the transfer. A cleaning device 910 that removes and collects toner is disposed. Photoconductor 50
The fixing device 110 is disposed substantially above the position 0 and downstream of the photoconductor 500 in the sheet transport path.

When the image forming apparatus functions as a copying machine, a document is first read when forming an image. Although not shown, an automatic document feeder that automatically feeds the document onto the contact glass is attached above the document reading device 300.

In the document reading device 300, a document is placed on the contact glass 320 by using an automatic document feeder or the like. This document is a document illumination light source 4
Traveling body 31 for reading comprising 30 and mirror 440
0 is scanned by reciprocating in the left-right direction in the figure, and the image sensor C installed behind the lens 310a
It is read as an image signal on a CD.

The image signal read by the image sensor CCD is digitized and processed. In advance, the photoconductor 50
0 is uniformly charged by the charging device 600 in the dark. The uniformly charged photoconductor 500 is irradiated with exposure light by emission of a laser diode LD (not shown) of the exposure apparatus 700 based on an image-processed signal, and is exposed through a known polygon mirror or lens. As a result, an electrostatic latent image is formed on the surface of the photoconductor 500. The electrostatic latent image moves with the rotation of the photoconductor 500, is visualized by the developing device 800, and further moves toward the transfer device 900.

On the other hand, the sheet cassette 5 of the sheet feeding section 200 stores unused sheets, and the uppermost sheet 2 on the bottom plate 60 which is rotatably supported is fed to the sheet feeding rollers 1 and 1.
The bottom plate 60 is pressed by the spring 8 so as to be pressed against the bottom plate 4. At the time of paper feeding for transfer, the paper feeding rollers 1 and 14 rotate as described later, and by this rotation, the uppermost paper 2a is sent out from the paper feeding cassette 5 and passes through the paper feeding rollers 4a and 4b. The sheet is conveyed to a pair of registration rollers 140.

The conveyance of the sheet sent to the registration roller 140 is temporarily stopped here. The registration roller 140 transports the paper at a timing such that the positional relationship between the toner image on the surface of the photoconductor 500 and the leading end of the paper is a predetermined position suitable for image transfer at the transfer position where the transfer device 900 is provided. To start.

The toner image is fixed on the sheet 2 a after the transfer while passing through the fixing device 110. The sheet having passed through the fixing device 110 is discharged by a discharge roller 120 in a discharge direction indicated by an arrow K1, and is sent to a discharge storage unit 410 to be discharged and stored. The image forming apparatus of this embodiment scans and reads a document as described above, digitizes the document, and copies it to paper. In addition to a function as a so-called digital copying machine, a control device (not shown) transfers image information of the document to a remote location. And a so-called printer function for printing image information handled by a computer on paper. [1] Example Corresponding to Claim 1 This will be described with reference to FIGS. FIG. 2 shows a state where the sheet cassette 5 is viewed from the side.
The same components as described above are used, and the novel configuration of the present invention is partially adopted. The description of the members already described is omitted as much as possible, and a new part will be described. The rotation direction is opposite to that of the paper feed roller 1 and the uppermost paper 2
An additional roller 14 whose contact time with a is earlier than that of the feed roller 1 is arranged between the separation claw 3 and the feed roller 1. The additional roller 14 may be provided with a plurality of similar rollers.

In this embodiment, the paper feed roller 1 can contact and release the uppermost sheet 2a, and can contact and release the uppermost sheet 2a. The present invention also relates to a sheet feeding device having one additional roller 14 which can release the contact at an early stage. Hereinafter, the operation of the separation sheet feeding will be described in detail.

In FIG. 2, in a sheet cassette 5, a sheet-like sheet 2 used for transfer is separated by a coil spring 8, the leading end of which is disposed at a corner of a front edge of the sheet cassette 5. And is housed.

When the paper 2 is fed from the paper feed cassette 5, the paper feed roller 1 and the additional roller 14 are first brought into contact with the uppermost paper 2a of the paper 2 in the paper feed cassette 5. In this state, when the paper feed roller 1 rotates in the clockwise direction 6 and the additional roller 14 rotates in the counterclockwise direction 7, the gap between the paper feed roller 1 and the additional roller 14 on the uppermost sheet 2a is increased. The portion receives a greater force than the force in the compression direction that has conventionally been generated between the paper feed roller 1 and the separation claw 3,
Further, since the distance between the paper feed roller 1 and the additional roller 14 is shorter than the distance between the paper feed roller 1 and the separation claw 3, the force in the compression direction is higher.

As a result, the feed roller 1 and the additional roller 14
As shown in FIG. 3, the uppermost sheet 2 b is largely deflected and floats upward while generating a large bending force, and the uppermost sheet 2 b is separated from the other sheets 2. At the same time, the leading end of the uppermost sheet 2b is completely separated from the separation claw 3 and released from contact, and the other sheets 2 continue to contact the separation claw 3.

Thereafter, when the paper feed roller 1 further rotates in the clockwise direction 6 and the additional roller 14 is raised by receiving an upward contact releasing force 15 as shown in FIG. The large bending force that was possessed is instantaneously released.

As a result, the sheet feeding roller 1 moves the uppermost sheet 2
b, a force generated in the direction from the paper feed roller 1 toward the transport rollers 4a and 4b, that is, a transport direction, that is, the transport force in the transport direction, and the leading end of the uppermost sheet 2a was in contact with the other sheets 2. As a result, an upward repulsive force on the sheet 2 is generated.

Due to the conveying force in the conveying direction and the upward repulsive force, the leading end of the uppermost sheet 2b instantaneously jumps over the separation claw 3, and the leading end of the uppermost sheet 2c as shown in FIG. The unit side is located above the separation claw 3, and the rear end side is in a state of being held down by the paper feed roller 1.

The leading end of the uppermost sheet 2c has inertia due to the above-described conveying force in the conveying direction and the upward repulsive force, and directly enters between the conveying rollers 4a and 4b, as shown in FIG. The uppermost sheet 2d is as shown in FIG. At the same time, when the paper feed roller 1 receives the contact release force 16 against the paper 2 as shown in FIG.
4b completely rotates the paper cassette 5 out of the paper cassette 5.
Paper is fed only on sheets. Example 2. Hereinafter, an example in which the paper feed roller 1 and the additional roller 14 are not cylindrical but have a shape in which a part of the peripheral surface is cut off will be described with reference to FIGS. In this example, as shown in FIG. 6A, the paper feed roller 1 has a shape in which a part of the peripheral surface of a column is cut away, and has an outer periphery 13 including an arc portion 11 and a chord portion 12 when viewed from the side. Paper feed roller 1 '. In this way, when the paper feed roller 1 'rotates, the rotation center of the paper feed roller 1'
, That is, the contact and non-contact time between the sheet feeding roller 1 ′ and the uppermost sheet 2 a is controlled.

As shown in FIG. 6B, a part of the peripheral surface of the cylinder is cut away at a position passing through the center of the circle, and the shape viewed from the side is smaller than the arc 11 in FIG. 6A. An arc 17 having a short perimeter and an additional roller 14 'having an outer periphery 19 comprising a chord 18 having a diameter are arranged together. FIG. 7 shows such a configuration.

In FIG. 7, the feeding roller 1 'and the additional roller 14' are fixed in height with respect to the feeding cassette 5, and immediately before feeding, the starting position of the feeding roller 1 'for contact with the feeding roller. 20 is brought into contact with the uppermost sheet 2a, and the respective positions are adjusted such that the additional roller contact start position 21 of the additional roller 14 'comes into contact with the uppermost sheet 2a.

From this state, when the paper feed roller 1 'rotates in the clockwise direction 6 and the additional roller 14' rotates in the counterclockwise direction 7 at the same speed as the paper feed roller 1 ',
The feed roller 1 ′ feeds the uppermost sheet 2 a in the direction of the conveying rollers 4 a and 4 b while bringing the arc portion 11 (see FIG. 6A) into contact with the uppermost sheet 2 a, and at the same time, the additional roller 1
4 ′, the uppermost sheet 2a is transported by the transport roller 4 while the arc portion 17 (see FIG. 6B) is brought into contact with the uppermost sheet 2a.
Send out in the direction opposite to the directions a and 4b.

As a result, the uppermost sheet 2a receives a force in the compression direction between the sheet feeding roller 1 'and the additional roller 14', generates a bending force, and floats upward. Then, the arc 11
When the time determined by the circumference and the rotation speed of the arc 17 elapses due to the feeding by the arc 17 shorter than the
At 4 ', the string 18 faces the uppermost sheet 2a, and the contact of the additional roller 14' with the uppermost sheet 2a is released.

At the same time, the uppermost sheet 2a is separated according to the sheet separating modes shown in FIGS. Thereafter, when a time determined by the circumference of the arc portion 11 and the rotation speed elapses, the string 12 is now opposed to the uppermost sheet 2a by the sheet feeding roller 1 ', and the uppermost sheet 2a in the sheet feeding roller 1' is turned. Is released, and the uppermost sheet 2a is transported only by the transport rollers 4a and 4b.
As a result, the uppermost sheet 2a is completely separated from the other sheets 2 and the sheet is fed so that only one sheet is fed out.

As described above, in the present embodiment, the additional roller 14 whose rotation direction is opposite to that of the paper feed roller 1 and whose contact end time with the uppermost sheet 2a is earlier than that of the paper feed roller 1 or 1 '. Or, by arranging 14 ′ between the paper feed rollers 1 and 1 ′ and the separation claw 3, the uppermost sheet 2a and other parts which have conventionally been provided between the paper feed roller 1 and the separation claw 3 are provided. Is separated between the paper feed roller 1 and the additional roller 14 to apply a larger bending force to the uppermost sheet 2a and completely separate the uppermost sheet 2a from the other sheets 2. As a result, only the uppermost sheet 2a was reliably conveyed by one sheet and fed.

Conventionally, a paper feed roller has been provided which abuts on and feeds the uppermost sheet stored in the paper feed unit, and a separating claw disposed at a corner of the front edge of the paper feed unit for separating paper. In the corner claw separation method, when the top sheet is sent out by the feed roller, a high sticking state or
Due to the high friction state, the top sheet and other sheets may stick together, and even with the separation claw, it may not be possible to remove only one top sheet from the sheet. In some cases, double feed, in which several sheets of paper are simultaneously transported together with paper, or non-feed, in which the uppermost sheet itself is not transported, may occur.

By using the sheet feeding method of this embodiment, a large bending is caused between the sheet feeding roller and the additional roller, and a large conveying force for the uppermost sheet and a large repulsive force for the leading end thereof, and a separation claw. Can be easily released.
Further, it is possible to enhance the separation property between the top sheet and the other sheets, and it is possible to reliably separate the top sheet from the other sheets and feed only one sheet from the sheet cassette. . [2] Example Corresponding to Claim 2 In the separation sheet feeding apparatus of this example, in addition to the separation sheet feeding method described in the above [1], the additional roller 14 'is driven by the sheet feeding roller 1'.
The feature is that it is interlocked with the drive of.

As shown in FIG. 10, a description will be given of a separation sheet feeding apparatus having a structure in which intermediate rollers 22a and 22b and an intermediate belt 23 are provided between the sheet feeding roller 1 and the additional roller 14.

An intermediate roller 22a is provided concentrically and integrally with the paper feed roller 1 ', and an intermediate roller 22b is provided so as to mesh with the intermediate roller 22a. There is a pulley P1 concentric with the intermediate roller 22b. Also, a pulley P2 is provided concentrically and integrally with the additional roller 14 ',
An intermediate belt 23 is stretched between the pulleys P1 and P2.

With the above configuration, only a single drive source is provided as a drive source for driving the paper feed roller 1 ', and the rotation of the paper feed roller 1' is first transmitted to the intermediate roller 22a.
Next, it is transmitted to the intermediate roller 22b using friction. Thereafter, the rotation of the intermediate roller 22b is transmitted to the intermediate belt 23, and finally transmitted to the additional roller 14.

At this time, the respective radii and lengths of the intermediate rollers 22a and 22b and the intermediate belt 23 are adjusted so that the rotation speed of the paper feed roller 1 'and the rotation speed of the additional roller 14' become equal. As described in detail in the first embodiment of the above [1], the uppermost sheet 2a can be completely separated from the other sheets 2 and can be fed separately by feeding out only one sheet.

In the above example, the link between the additional roller 14 'and the paper feed roller 1' was performed using the intermediate rollers 22a and 22b and the intermediate belt 23.
The same operation can be obtained by a configuration in which an intermediate gear is interposed instead of the third gear. Also, the intermediate rollers 22a, 22
A configuration in which b is replaced by a gear may be adopted. As described above, it is possible to drive the two rollers of the sheet feeding roller 1 'and the additional roller 14' with only a single drive source. [3] Example Corresponding to Claim 3 This example relates to a form of a separation claw. The form of the separation claw according to this example is as shown in FIG. 9A, and will be described later. The separation claw shown in FIG. 9 can be used in place of the separation claw 3 in the separation paper feeder shown in FIGS.

In FIG. 9A, the separation claw 3 'provided at each corner of the sheet cassette 5 has a projection length in the width direction of the uppermost sheet rather than a projection length 24 in the transport direction. 25 is configured to have a long shape. Here, the transport direction and the width direction of the uppermost sheet are orthogonal to each other in the same plane.

One or more separation claws 3 ', 3' may be provided between the two separation claws 3 ', 3'.
It can also be configured as two separate claws. However, FIG.
As shown in (b), in the case of a separation claw 3 ″ having a triangular shape or the like, the projection length (in the transport direction) of the separation claw 3 ″ installed in the paper feed cassette 5 in the transport direction ( Vertical length)
By taking the projection length (horizontal length) 25 in the width direction of the top sheet, the projection length 25 in the width direction of the top sheet is larger than the projection length 24 in the transport direction. It is only necessary to obtain a long shape.

In other words, the vertical length 24 is equal to the horizontal length 2
With reference to FIG. 9, a separation sheet feeding apparatus in which two sets of separation claws 3 shorter than 5 are attached to both corners of the front edge of the sheet cassette will be described with reference to FIG.

With the above-described configuration, as described in the above-described separated sheet feeding mode [1], the top sheet 2b is instantaneously released from the large bending force of the top sheet 2b, and is obtained in the transport direction. When the uppermost sheet 2c jumps over the separation claw 3 'due to the conveyance force and the upward repulsion, the protrusion length of the separation claw 3' in the conveyance direction is reduced because the vertical length 24 is relatively short. Therefore, the above-described difficulty in jumping over is reduced, and since the horizontal length 25 is relatively long, the other papers 2 can be pressed over a wide area in a direction perpendicular to the transport direction of the paper feed cassette 5, The separability from the uppermost sheet 2c is improved. As described above, the uppermost sheet 2a is completely separated from the other sheets 2 and the sheet is fed so that only one sheet is fed.

In addition to the above example, a part of the shape of the paper feed roller 1 is cut away, and as shown in FIG. 6A, a paper feed roller having an outer periphery 13 composed of an arc portion 11 and a chord portion 12 as viewed from the side. As shown in FIG. 6B, a part of the shape is cut off similarly to the paper roller 1 ′, and an outer periphery 19 composed of an arc portion 17 and a chord portion 18 having a shorter circumference than the arc portion 11 when viewed from the side. FIG. 10 shows an example of a separation sheet feeding apparatus using the additional roller 14 ′ having the following.

In this example, only the rotation of the paper feed roller 1 'and the additional roller 14' is performed without changing the height of the paper feed roller 1 'and the additional roller 14' with respect to the paper feed cassette 5, and the uppermost portions of both rollers are rotated. This is a separation sheet feeding device that controls contact and release of the sheet 2a to obtain the above-described operation.

The separation claw 30 shown in FIG. 11 also satisfies the conditions of this embodiment. That is, the entire front edge of the sheet cassette 5 is
A shape in which the projection length 25 in the width direction of the top sheet is longer than the projection length 24 in the conveyance direction, that is, the conveyance direction is narrow, and the width direction of the top sheet is the width of the sheet cassette 5. There is an example in which the vertical and horizontal separation claw 30 has a large length dimension.

In this embodiment, the amount of protrusion of the separation claw in the transport direction is reduced, so that the transportability of the uppermost sheet is improved.
Further, the width of the separation claw in the sheet cassette portion in the width direction is increased, and sheets other than the uppermost sheet can be reliably retained in the sheet cassette. This makes it possible to more reliably separate the uppermost sheet from other sheets and feed only one sheet from the sheet cassette. [4] Example Corresponding to Claim 4 FIG. 12 shows an outline of a separation sheet feeding apparatus according to this example. In this example, in addition to the configuration in each of the examples described above, the additional roller 14 ′ and the separation claw, in which the rotation axis directions 27 a and 27 b of the additional roller 14 ′ are perpendicular to the direction from the additional roller 14 ′ to the separation claw 3 ′. This is a system having one or more combinations of 3 ′.

In this embodiment, two separation claws 3 ′ having a rectangular parallelepiped shape are provided at both corners of the front edge of the sheet cassette 5. Then, the two additional rollers 14 'are moved in the directions 28a, 28 toward the two separating claws 3', respectively.
The additional roller shafts 27a and 27b, which are the rotation axes of the two additional rollers 14 ', are disposed at positions perpendicular to each other.

With this configuration, the feed roller 1 ′ (for example, see FIG. 7), which is not shown in FIG. 13 because it is located upstream of the additional roller 14 ′ in the transport direction, has a clockwise direction of 6. When the additional roller 14 'rotates in the counterclockwise direction, the portion of the uppermost sheet 2a between the feed roller 1' and the additional roller 14 'is the same as the previously described FIG. It is largely bent like the upper sheet 2b.

At the same time, since the axis of the additional roller 14 'is inclined, the uppermost sheet 2a is largely pulled toward the separation claw 3 (or 3').

At this time, the rotation of the two additional rollers 14 'is determined by the rotation of the additional roller shafts 27a,
7b, which is the direction perpendicular to the direction 7a, is strongly pulled. As a result, both corners of the leading edge of the uppermost sheet 2a contacting the separation claw 3 'at the tip of the directions 28a, 28b, and the separation claw 3 The contact with the 'is easily released, and the separability is improved. As described above, the uppermost sheet 2a is replaced with the other sheets 2
Are completely separated from each other, and only one sheet is sent out and fed.

As related to the above example, two additional rollers 1 satisfying the configuration of the above example with a single drive source.
4 as a mechanism for driving the rotary branching mechanism 2 in two directions
FIG. 14 shows an example in which 9 is provided. The bi-directional rotary branching mechanism 29 shown in FIG. 14 has a configuration in which two gears having different radii in the direction of the rotation axis are connected, a so-called bevel gear mechanism, and drives the additional roller 14 'to rotate.

In this embodiment, since the portion of the uppermost sheet which comes into contact with the separation claw of the uppermost sheet can be most effectively pulled, the release of the contact with the separation claw is easiest. ], [2], [3], etc., it is possible to separate the uppermost sheet from other sheets and feed only one sheet from the sheet feeding unit or the sheet cassette more reliably than the configuration described in [2], [3], etc. . [5] Example Corresponding to Claim 5 In this example, the uppermost sheet 2a is placed in the sheet cassette 5 using the separation sheet feeding apparatus having the configuration described in any one of the above [1] to [4]. Between the feed roller 1 (or 1 ′) and the additional roller 14 (or 14 ′) in the forward and reverse directions, one or more times. Send.

This will be described below with reference to FIGS. As described in the above [1], the paper feed roller 1 rotates in the clockwise direction 6 and the additional roller 14 rotates in the counterclockwise direction 7, and the uppermost sheet 2a shown in FIG.
In this example, the sheet supply roller 1 and the additional roller 14 are rotated in the reverse direction when the sheet is bent like the uppermost sheet 2b shown in FIG.

That is, by rotating the paper feed roller 1 in the counterclockwise direction 7 and rotating the additional roller 14 in the clockwise direction 6, the uppermost sheet 2b shown in FIG. The shape is returned like the upper sheet 2a.

The above-mentioned reciprocating motion is repeatedly performed once or plural times with respect to the uppermost sheet 2a. As a result, it is possible to reliably disperse the sticking phenomenon between the top sheet 2a and the other sheets 2 that are in a strong sticking state or in a high friction state due to variations in sheet characteristics,
Separation can be performed.

According to the present embodiment, it is possible to surely separate the paper in the strong sticking state or the high friction state from the other paper. Further, the separation paper feeding device using the separation claw of the above [3] can be used as it is, and furthermore, it is provided in a device having a paper feeding cassette such as a copying machine, a facsimile, a printer, etc. Alternatively, it is possible to cope with various paper types in a high friction state. Of course, the present invention can be applied to a separation sheet feeding apparatus of a type in which sheets are stacked directly on a sheet feeding unit instead of a sheet feeding cassette type. [6] Example Corresponding to Claim 6 In this example, the paper separation in the above [5] is performed with respect to the paper supply from the paper supply cassette 5 (or the paper supply unit) after being left for a long period of time or in the long-term standby state. carry out.

In this example, as described in the above [5],
One or more repetitions of the forward and reverse rotations of the paper feed roller 1 'and the additional roller 14' are performed for paper feed from the paper feed cassette 5 after being left for a long time or in a standby state for a long time. Do it. This operation is performed before paper feeding,
It is possible to surely separate and separate the top paper 2a and the other paper 2 that are in a strong sticking state or a high friction state due to being left for a long time or being in a standby state for a long time. .

To detect that the apparatus has been left for a long period of time or has been in the standby state for a long period of time, for example, a sensor for detecting the passage of a sheet is provided near the sheet feeding rollers 4a and 4b, and information from this sensor is received. It can be performed by making a determination by the control means when a predetermined time has elapsed after a lapse of time.

In this embodiment, the forward / reverse operation is performed only after the predetermined time has elapsed, so that useless forward / reverse operation can be omitted. [7] An example corresponding to claim 7 The examples described in [1] to [6] are applied to the image forming apparatus described with reference to FIG. It can be performed reliably. The image forming apparatus can include a copying machine, a facsimile, a printer, a printing machine, and the like. Further, the present invention can be applied to a separation and feeding device for bills and securities.

[0071]

According to the first aspect of the present invention, a large conveying force and a large repulsive force against the leading end of the uppermost sheet-like medium are provided, and at the same time, the contact with the separation claw is easily released. Feeding or non-feeding can be prevented, and reliable separation performance can be obtained even when feeding paper at high speed.

According to the second aspect of the present invention, it is possible to drive the two rollers of the sheet feeding roller and the additional roller with only a single drive source.

According to the third aspect of the present invention, the amount of protrusion of the separation claw in the conveyance direction is reduced, so that the conveyance property of the uppermost sheet-like medium is improved, and the separation claw is expanded in the width direction in the sheet feeding portion. And the sheet-like medium other than the uppermost sheet-like medium can be reliably retained in the sheet feeding unit. This ensures that the uppermost sheet-like medium is
It is possible to separate the sheet from other sheet-shaped media and feed only one sheet from the sheet feeding unit.

According to the fourth aspect of the present invention, since the uppermost sheet can be pulled most effectively to the portion of the uppermost sheet that comes into contact with the separation claw, the contact with the separation claw can be released most easily. As a result, it is possible to more reliably separate the uppermost sheet from the other sheets and feed only one sheet-like medium from the sheet feeding unit.

According to the fifth aspect of the present invention, it is possible to surely separate the uppermost sheet-like medium and the other sheet-like medium in a state of being strongly adhered to various paper types or in a state of high friction. it can.

According to the sixth aspect of the present invention, the forward / reverse operation is performed only when the predetermined time has elapsed, so that useless forward / reverse operation can be omitted.

According to the seventh aspect of the present invention, in an image forming apparatus having a paper feed cassette such as a copying machine, a facsimile, a printer, etc., it is possible to reliably feed and separate sheets.

[Brief description of the drawings]

FIG. 1 is a schematic front view illustrating an outline of an image forming apparatus.

FIG. 2 is a front view illustrating a configuration of a separation sheet feeding unit device.

FIG. 3 is a front view illustrating a configuration of a separation sheet feeding unit device.

FIG. 4 is a front view illustrating a configuration of a separation sheet feeding unit device.

FIG. 5 is a front view illustrating a configuration of a separation sheet feeding unit.

FIG. 6A is a front view of a feed roller with a part of the peripheral surface cut off, and FIG. 6B is a front view of an additional roller with a part of the peripheral surface cut off.

FIG. 7 is a front view illustrating a configuration of a separation sheet feeding unit device.

FIG. 8 is a schematic front view illustrating a means for interlocking a paper feed roller and an additional roller.

FIG. 9A is a plan view of a sheet feeding cassette, and FIG.
FIG. 2B is a plan view of a main part of the sheet cassette.

FIG. 10 is a perspective view of a sheet feeding cassette.

FIG. 11 is a partial plan view of the sheet cassette illustrating a separation claw.

FIG. 12 is a partial plan view of a sheet cassette illustrating an arrangement of additional rollers.

FIG. 13 is a partial plan view of a sheet cassette illustrating an arrangement of additional rollers.

FIG. 14 is a front view illustrating a conventional separation sheet feeding device.

FIG. 15 is a diagram illustrating a conventional separation mechanism.

[Explanation of symbols]

 1, 1 'paper feed roller 14, 14', 14 "additional roller 3, 3 ', 3" separation claw

Claims (7)

[Claims] A sheet feeding unit configured to rotate a sheet feeding roller in contact with an uppermost sheet-shaped medium stacked on the sheet feeding unit to feed the uppermost sheet-shaped medium in a sheet feeding direction; In the separation sheet feeding device for separating the uppermost sheet-like medium from the other sheet-like media and feeding the separated sheet-like medium with the separation claw disposed at the leading end of the sheet feeding roller, the rotation direction is opposite to the rotation direction of the sheet feeding roller,
And one additional roller whose contact end time with the uppermost sheet-shaped medium is earlier than the contact end time of the paper feed roller,
Alternatively, a separation sheet feeding device is provided between the separation claw and the sheet feeding roller. 2. The separation sheet feeding device according to claim 1, wherein
A separation sheet feeding device, comprising: means for interlocking the driving of the additional roller with the driving of the sheet feeding roller. 3. The separation sheet feeding device according to claim 1, wherein the separation claw is projected in a direction perpendicular to the sheet-like medium conveyance direction rather than a projection length of the separation claw in the sheet-like medium conveyance direction. Separation nail with a long projection length
Or a separation sheet feeding device comprising a plurality of sheet feeding devices. 4. The separation sheet feeding device according to claim 1, wherein a rotation axis direction of the additional roller and a direction from the additional roller to the separation claw are perpendicular to each other. A separation sheet feeding device comprising one or a plurality of combinations of separation claws. 5. The paper feed separation device according to claim 1, wherein the rotation of the paper feed roller and the additional roller is performed while the uppermost sheet medium is in the paper feed unit. Is repeated once or plural times in the forward and reverse directions. 6. A sheet separating apparatus according to claim 5, further comprising detecting means for detecting that the sheet-like medium in the sheet feeding section has been left for a predetermined time, wherein the detecting means detects whether the sheet-like medium has been left for a predetermined time. A separation sheet feeding device wherein the rotation of the sheet feeding roller and the additional roller is repeated once or plural times in forward and reverse directions before sheet feeding. 7. An image forming apparatus comprising a charging, exposing, developing, and transferring process means for transferring an image of a photoreceptor onto a sheet-like medium sent from a sheet feeding unit, fixing the sheet, and discharging the sheet. Item 7. An image forming apparatus comprising the separation sheet feeding device according to any one of Items 1 to 6.