JPH10181909A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed paper surely separated without giving residual deformation even in a cut sheet of any thickness, in a paper feeder. SOLUTION: This paper feeder is provided with a paper feed roller 31 brought into contact with a loaded cut sheet 11 from one surface thereof to feed paper successively delivered and a cantilever friction member 33 separating one by one the cut sheet 11 by friction contact when brought into contact with a tip end part of the loaded cut sheet 11. Of a plurality of the friction members 33 arranged in a width direction of the cut sheet 11, a friction member 33(1) is brought into contact with the tip end part of the cut sheet 11 at a different angle from friction members 33(2), 33(3), to perform initialized and stable handling by the friction member 33(1), on the other hand, auxiliary handling by the friction members 33(2), 33(3).

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 for sequentially feeding and feeding a stacked cut sheet from one side thereof by a feed roller contacting the cut sheet, and more particularly, to a cantilever extending in a cut sheet feeding path. The present invention relates to a sheet feeding device that separates cut sheets one by one by frictional contact when a friction member comes into contact with a leading end portion of the cut sheet to be fed out, thereby preventing double feeding, and includes a copying machine, a printer, and a facsimile machine. Feeding of recording sheets and originals, etc.
It is used for feeding an original of an image reading apparatus and other various cases in which a plurality of stacked cut sheets are fed out one by one and used.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 7-196186 discloses such a sheet feeding device. In this conventional apparatus, as shown in FIG. 6, a friction member e extending from below into a feeding path of a cut sheet b stacked on a paper feed tray a by a paper feed roller c and having a lower end pivotally supported by a shaft d is provided. 6, which comes into contact with the entire width of the leading end of the cut sheet b which is fed out each time the paper feed roller c makes one rotation, resists the bias of the restoring spring f, and is displaced as shown by the phantom line in FIG. , The fed cut sheet b is separated into individual sheets so that the sheets can be fed one by one without double feeding.

The angle α between the friction surface of the friction member e and the uppermost surface of the cut sheet b is set in a range of 85 to 55 degrees so that the friction member e can be surely separated by the friction.

[0004]

By the way, fine adjustment is required for separating the cut sheet by the friction member as described above. According to experiments by the present inventors, when the cut sheet advances while pushing away the friction member, it is better to weaken the restoring force of the friction member to the initial position so that the friction member does not receive residual deformation. In order to surely separate the cut sheets, it is better to increase the restoring force so as to increase the frictional force between them. These are incompatible and difficult to set in a well-balanced manner. In addition, since the cut sheet is easy to bend, that is, the stiffness differs depending on the paper quality and thickness, the friction resistance received from the same friction member varies, and the separation performance also varies.

The friction member e disclosed in the above publication is arranged at a downstream position in the sheet feeding direction relatively far from a nip position where the sheet feeding roller c comes into contact with and feeds out the cut sheet b. It is fed out and abuts against the friction member e, and is separated while causing buckling due to frictional contact therewith. Since the cut sheet b is provided with a large degree of freedom of deformation between the nip portion of the sheet feeding roller c and the friction member, when the friction member e tilts when passing through the friction member e while pushing away the friction member e. It becomes easier to escape from the friction member e,
The cut sheet b having any thickness is hardly subjected to residual deformation.

However, in such a conventional apparatus, the separation performance of the cut sheet b is unstable, and double feed sometimes occurs. Since the friction member e of the conventional device has only a uniform friction surface in the frictional contact direction of the cut sheet b, the front end of the cut sheet b approaches the front end while pushing away the friction member e, so that the slippery contact is made. The cut sheet b may be slipped off the friction member e before the cut sheet b is sufficiently separated, and may come off in a double feed state before the cut sheet b is sufficiently separated. Although the setting of the angle somewhat suppresses this, it is insufficient, and double-feeding is particularly likely to occur in a cut sheet b that is weak due to paper quality and thinness.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding device capable of reliably separating and feeding cut sheets of any thickness without causing residual deformation.

[0008]

According to a first aspect of the present invention, there is provided a sheet feeder comprising: a sheet feed roller for sequentially feeding a cut sheet in contact with one side thereof and feeding the cut sheet; A cantilevered friction member that separates the cut sheets one by one by frictional contact when coming into contact with the leading end of the stacked cut sheets is provided. A plurality of friction members are arranged in the width direction of the cut sheet, and a certain friction is provided. The member comes into contact with the front end of the cut sheet at an angle different from that of the other friction members.

As described above, one of the plurality of friction members arranged in the width direction of the cut sheet is brought into contact with the leading end of the cut sheet at an angle different from that of the other friction members. The frictional member having a large contact angle allows the initial and stable separation of the cut sheet, while the frictional member having a small contact angle performs the auxiliary separation over time and shares the deformation stress of the cut sheet. Therefore, cut sheets of any thickness can be reliably separated without giving any residual deformation and double feed can be prevented.

Further, when at least one pair of paper feed rollers is provided, if the angle at which the friction member closer to the center in the width direction of the cut sheet abuts on the leading end of the cut sheet is made larger, the paper feed roller pair is used. Since the feeding force of the cut sheet is applied in the center direction, the cut sheet is naturally deformed so as to have a middle height in the width direction, and the cut sheet can be separated along the naturally deformed shape,
Separation performance is further improved, and double feeding of cut sheets can be more reliably prevented.

Further, if the height of the friction member having a larger angle at which the front end portion of the cut sheet comes into contact is made lower, the height between the friction members as viewed from the front end side of the cut sheet becomes substantially uniform, so that the cut sheet becomes a friction member. There is no danger of giving residual deformation when overcoming.

[0012]

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

This embodiment is shown in FIGS.
5 illustrates a case of a sheet feeding device 1 that feeds recording sheets by a copying machine as shown in FIG. The copying machine is of a digital type, and the scanning optical system 2 scans a document placed manually on a platen glass or automatically sent by a document feeder (not shown). The scanned image is formed on the image sensor 4 of the image reading unit 3 and converted into an electric image signal. This image signal is sent to the print head 5, and the print head 5 emits a laser beam 6 modulated by the image signal to the photosensitive drum 7 to perform image exposure.

The photosensitive drum 7 is located substantially at the center of the copying machine body 10, and its surface is uniformly charged by a charging brush 8 for the image exposure. The electrostatic latent image formed by the image exposure on the charged surface of the photosensitive drum 7 is developed by the developing unit 9 with a toner to become a visible image. This visible image is transferred to the cut sheet 11 sent from the paper feeding device 1 or the like by the transfer roller 12 or the like. The cut sheet 11 after the transfer is sent to a fixing device 13 and subjected to a fixing process. Thereafter, the cut sheet 11 is discharged to a discharge tray 15 directly or by a discharge roller 14.

In the main body 10 of the copying machine, a paper feeder 16 for feeding a fixed or regular cut sheet 11 is provided at the bottom or the like. The paper feeding device 16 includes a paper feeding cassette 17 that can be taken in and out, and a paper feeding cassette 1 that is mounted.
And a paper feed roller 18 in the copying machine main body 10 for feeding out the cut sheet 11 in the main body 7. The paper feeder 1 is shown as being used as a so-called manual paper feeder, and is provided so as to protrude from the side of the copier main body 10. Thus, a plurality of cut sheets 11 of paper quality and size not prepared in the copying machine main body 10 can be stacked as needed, or one sheet can be placed and fed.

The sheet feeding device 1 is used for a cut sheet 11 to be used.
3, the left and right side guides 22 provided on the sheet feed tray 21 can be adjusted in position according to the width of the cut sheet 11 as shown in FIG. The left and right side guides 22 are interlocked by an interlocking gear 23 provided in the sheet feeding tray 21, and feed the cut sheets 11 of any size in a so-called center-aligned manner in which the centers are aligned at the same position.

Such a manual paper feeder 1 includes a postcard,
Various cut sheets 11 other than paper, such as a resin sheet for an overhead projector, or a sheet of thinner paper than plain paper, are often used. In some cases unexpected types of cut sheets 11
Is sometimes used.

The sheet feeding device 1 is an auxiliary device that is used less frequently, and a small and simple sheet feeding mechanism is desired. On the other hand, sheet feeding performance that can handle various cut sheets 11 is required. In this embodiment, as shown in FIGS. 1 and 3, this paper feeding device 1 is
While being in contact with the cut sheet 11 fed out by the above, by the frictional contact at that time, the cut sheet 11 of the second or lower order that is to be multi-fed to the outermost cut sheet 11
In this case, a simple separation system using a friction member 33 that hinders the progress of the sheet feeding is used, and moreover, a stable sheet feeding performance can be exhibited even for various cut sheets 11. However, the sheet feeding device of the present invention can be applied to a usual sheet feeding device of a copying machine, and can also be applied to automatically feed a document. As described above, the present invention can be applied to a machine other than a copying machine.

The paper feed roller 31 of the paper feeder 1 is provided on a side surface of the copying machine main body 10. The paper feed tray 21 of the paper feeder 1 holds the cut sheet 1 fed from the paper feeder 16.
1 and extends slightly obliquely upward from a base 36 having an outer guide 35 of a paper passing path 34 for receiving the photosensitive drum 7 toward the photoreceptor drum 7, and the base 36 hinges to the copying machine main body 10 at a side (not shown). The paper passage path 34 can be opened and closed for jam processing and the like by being rotated integrally with the paper feed tray 21 about this hinge connection part.

The paper feed tray 21 has a rear end portion pivotally supported by a shaft 24 and has a push-up plate 26 urged upward by a spring 25.
1 is pressed against the paper feed roller 31 and the paper feed roller 31 is rotated, so that the outermost surface is
In the first embodiment, the uppermost cut sheet 11 can be fed and fed. The surface of the paper feed roller 31 is made of rubber such as EPDM, for example, and has an appropriate frictional force.
However, it is not limited to this.

The paper feed roller 31 has a substantially half-moon shape, and its notch faces the cut sheet 11 when paper is not fed. Then, the cut sheet 11 is fed out by contacting the sheet. When the sheet is not fed, the cam 31b, which rotates in synchronization with the sheet feeding roller 31, comes into contact with the cam follower 26a of the push-up plate 26 to push down the push-up plate 26 against the spring 25. The sheet 11 is largely separated from the sheet feeding roller 31 so that the cut sheet 11 can be easily loaded or pulled out by hand until the sheet 11 comes into contact with the predetermined position of the sheet feeding tray 21, that is, the friction member 33 only when the sheet is not fed.

When the paper feed roller 31 starts rotating during paper feeding, the cam 31b comes off the cam follower 26a at the same time or slightly later when the notch portion does not face the cut sheet 11, so that the push-up plate 26 becomes free. The cut sheet 11 is pressed against the outer diameter surface of the sheet feed roller 31 that has begun to be rotated by the bias of the spring 25 so that sheet feeding is performed.

The friction member 33 according to the first embodiment is made of a rigid plate, and the cut sheet 11 is brought into frictional contact when the cut sheet 11 is fed out by the paper feed roller 31.
1 is separated one by one, and the sheet feeding roller 31 contacts the uppermost surface of the stacked cut sheets 11 and feeds out the sheet. It extends from the lowermost surface side to the feeding path of the cut sheet 11, and the feeding path 3
The lower portion is provided in a cantilevered support state in which the lower portion is fixed to the support wall 37 rising below the bottom by an appropriate method such as bonding or screwing.

Here, the mechanism of separation by the friction member 33 will be considered. The actual loosening mechanism is based on partial buckling of the cut sheet 11 caused by the cantilevered friction member 33. This will be described below in principle and qualitatively for the sake of simplicity.

Now, as shown in FIG. 5A, consider a condition in which the cut sheet 11 to be advanced by the force F receives a frictional force on the friction surface 33a of the friction member 33 and is balanced.
The coefficient of friction mu _B against the cut sheets 11 of the friction surface 33a of the friction member 33, when the contact angle is theta (fixed value in this case), when Fcosθ = μ _B · Fsinθ ...... (1), because balanced, mu _B · _tanθ <1 (cut sheet 11 _{proceeds.) ...... (2) μ B} · tanθ ≧ 1 ( cut sheet 11 is stopped.) (3) the relationship is established. Shows the critical value of the contact angle θ traveling cut sheet 11 is slipped on the range of suitable friction coefficient mu _B in (b) of FIG.

In principle, from the above equations (2) and (3),
Whether the progression of the cut sheet 11 regardless of the force F, are to be understood as determined only by the friction coefficient mu _B and contact angle theta. Therefore, assuming that the friction coefficient μ _B does not change, in order to loosen the cut sheet 11, it is necessary to make a difference in the contact angle θ between the outermost cut sheet 11 and the next lower cut sheet 11 with respect to the friction surface 33a. It is. That is, the meaning of the separation by the friction member 33 is that the outermost cut sheet 11 is used.
Is to drive only the contact angle θ from the stop area of the cut sheet 11 to the advancing area.

However, usually, the outermost surface of the cut sheet 11 is very close to the lowermost one, and is close to the close contact. It is considered that there is almost no difference in the angle θ.

The friction member 33 is brought into frictional contact with the cut sheet 11 fed by the paper feed roller 31,
As shown in FIG. 5C, the outermost cut sheet 11 is made to buckle more than the next or lower cut sheet 11,
The contact angle θ of the outermost cut sheet 11 works so as to be much smaller than the contact angle θ of the next lower cut sheet 11, and the cut sheet 11 is separated into individual sheets, and the outermost cut sheet 11 is cut. Only the sheet 11 passes, and the cut sheet 11 below the next position is stopped to prevent double feeding.

However, in practice, the cut sheet 11 is easy to bend depending on the paper quality and thickness, that is, the stiffness is different, and the cut sheet 11 fed out by the paper feed roller 31 is a friction member 33. Therefore, it is difficult to be surely separated and handled without being subjected to residual deformation.

In the present embodiment, the friction member 33 uses, for example, a synthetic resin plate or a metal plate. The thickness of the synthetic resin plate or the like may be a thickness capable of having a rigidity that does not cause significant deformation when the cut sheet 11 abuts. Friction member 33
The friction surface 33a is made of a material having a large frictional force such as urethane resin on its surface by silk screen printing or the like.
The required coefficient of friction is obtained. Friction surface 33
It is preferable that a has a static friction coefficient of about 1.0 to 1.5 with respect to general high-quality paper. The angle between the lower part of the friction surface 33a and the outermost cut sheet 11 is 90 degrees or more.
Preferably, it is set to 120 degrees.

Further, in the present embodiment, the friction member 33
Are arranged in the width direction of the cut sheet 11. Specifically, as shown in FIG. 1 and FIG.
By (1), 33 (2), and 33 (3) being cantilevered at different angles from the support wall 37 at positions separated from each other, the friction member 33 (1) can be changed to the friction members 33 (2), 3 (3).
3 (2) so as to come into contact with the front end of the cut sheet 11 at an angle different from that of the cut sheet 11.

The friction member 33 (1) of the plurality of friction members 33 arranged in the width direction of the cut sheet 11 as described above.
Is brought into contact with the front end of the cut sheet 11 at an angle different from that of the friction members 33 (2) and 33 (3), so that the friction member 33 (1) can perform initial and stable loosening of the cut sheet 11. Meanwhile, the friction members 33 (2) and 33 (3)
The auxiliary stress is applied over time to disperse the deformation stress of the cut sheet 11. Therefore, the cut sheet 11 having any thickness can be reliably separated without giving any residual deformation, and double feed can be prevented. In FIG. 2, the friction members 33 are arranged symmetrically with respect to the center in the width direction of the cut sheet 11, but the friction members 33 may be arranged with one side as a reference or asymmetrically.

Further, in the present embodiment, the sheet feeding roller 31
The cut sheet 11 is provided in a pair symmetrically with respect to the center position of the sheet passing path corresponding to the center alignment of the cut sheet 11, so that the cut sheet 11 can be fed to the feeding destination without skew. Can be. The pair of left and right paper feed rollers 31 can be relatively stably fed without skew even when the cut sheets 11 are aligned on one side and contact a position deviated from the center position depending on the size.

When the pair of left and right paper feed rollers 31 is provided, as shown in FIG. 2, the friction members 33 (1)
May be arranged at an intermediate position between the sheet feeding roller pair. In such a case, the feeding force of the cut sheet 11 fed by the pair of right and left feed rollers 31 acts on the center position, so that the cut sheet 11 naturally deforms to have a middle height in the width direction. This does not cause skew of the cut sheet 11 fed and fed by the frictional resistance. The same applies when a larger number of paper feed roller pairs are provided. In a mode in which only one sheet feeding roller 31 is provided, it is preferable to provide friction members on both sides of the sheet feeding roller 31.

The paper feed roller 31 may be provided at a biased position or a plurality of paper feed rollers may be provided at various positions.
The number and the number of friction pieces may be provided so as to be balanced in accordance with the position.

When the paper feed rollers 31 are provided as a pair, the friction member 33 near the center of the cut sheet 11 in the width direction is provided.
The angle of contact with the leading end of the cut sheet 11 in (1) is
If it is larger than that of the peripheral friction members 33 (2) and 33 (3), the leading end of the cut sheet 11 can be initially and stably separated only by the friction member 33 (1) near the center in the width direction. . Therefore, in this case, the cut sheet 11 can be separated along a naturally deformed shape without twisting or the like, so that the separating performance can be further improved and the double feed of the cut sheet 11 can be more reliably prevented. In addition, the height of the friction member 33 (1) having a large angle at which the leading end of the cut sheet 11 abuts is changed to the friction member 33 having a small angle.
(2), if lower than 33 (3), cut sheet 1
Since the heights between the friction members as viewed from the front end side are substantially the same, there is no possibility that residual deformation will occur even when the cut sheet 11 gets over the friction members 33.

Further, in the present embodiment, the friction member 33
As shown in FIG. 1, the friction surface 33a is located inside the outer shape of the paper feed roller 31, so that the paper feed roller 31 comes into contact with the cut sheet 11 and feeds from the nip position N. The distance of the member 33 to the friction surface 33a is extremely small as compared with the above-described conventional example. For this reason, the cut sheet 1 between the nip position N and the friction surface 33a is
1 to reduce the degree of freedom of deformation,
3a, it is easy to be separated and easily separated, so that the separating performance is improved, and it is possible to cope with high-speed paper feeding.

One rotation of the feed roller 31 feeds out one cut sheet 11, and the rear end of the cut sheet 11 is moved to the nip position N.
Is released, the friction member 33 is fed, but is released from the pressing by the cut sheet 11 and becomes free, so that it returns to the original state. At this time, the cut sheet 11 of the next rank or less which is about to be fed to the cut sheet 11 to be fed.
Is on the slope of the friction member 33 (1), which forms the steepest slope, so that it can be prevented from being pushed back to its original position due to gravity drop and hindering the next sheet feeding while being disturbed. In this case, the angle setting of the friction member 33 was suitable and convenient. However, for this purpose, the friction member 33 may be elastically returned.

Further, the upper end of the friction member 33 may be set slightly lower than the rotation shaft 31c of the paper feed roller 31. Then, when the base 36 of the sheet feeding device 1 is opened to open the sheet passing path 34, the upper end of the friction member 33 is
Is pulled forward through Next, when the base 36 is closed, the friction member 33 returns to the original position only by slightly raising the rotation shaft 31c, so that there is no problem.

In the present embodiment, only the case of the paper feeder of the draw-out type has been described, but it is needless to say that the present invention is not limited to this and can be similarly applied to the paper feeder of the draw-out type.

[0041]

According to the present invention, a plurality of friction members are arranged in the width direction of the cut sheet, and a certain friction member is brought into contact with the front end of the cut sheet at an angle different from other friction members. Thus, while a certain friction member performs initial and stable separation of the cut sheet, another friction member takes time to perform auxiliary separation to disperse the deformation stress of the cut sheet. Therefore, cut sheets of any thickness can be reliably separated without giving any residual deformation and double feed can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an installation state of a friction member of the sheet feeding device of FIG.

FIG. 3 is a cross-sectional view of substantially the entire sheet feeding device of FIG. 1;

FIG. 4 is a schematic configuration diagram of a copier including the sheet feeding device of FIG. 1;

FIGS. 5A and 5B are explanatory views illustrating the principle of separation of cut sheets by a friction member to which the present invention is applied, wherein FIG.
(B) is a graph showing boundary conditions for stopping and advancing when the cut sheet comes into contact with the friction member, and (c) is a conceptual diagram showing a state where the cut sheet is loosened by the friction member.

FIG. 6 is a cross-sectional view showing a conventional sheet feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper feeder 10 Copier main body 11 Cut sheet 21 Paper feed tray 26 Push-up plate 30 Feeding-out path 31 Paper feed roller 33 Friction member 33a Friction surface 37 Support wall

Claims (3)

[Claims] 1. A sheet feed roller that comes in contact with a stacked cut sheet from one side thereof and sequentially feeds out the cut sheet, and the cut sheets are stacked one by one by frictional contact when the sheet comes into contact with the leading end of the stacked cut sheets. In a paper feeder provided with a cantilevered friction member that separates a plurality of friction members, a plurality of friction members are arranged in the width direction of the cut sheet, and a certain friction member contacts the front end of the cut sheet at an angle different from other friction members. A sheet feeding device characterized by being in contact with the sheet feeding device. 2. The sheet feeding device according to claim 1, wherein when at least one pair of sheet feeding rollers is provided, the angle at which the friction member closer to the center in the width direction of the cut sheet abuts on the leading end of the cut sheet is increased. . 3. The sheet feeding device according to claim 2, wherein the height of the friction member having a smaller angle with which the leading end of the cut sheet abuts is reduced.