JPH10181911A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed a cut sheet stably one by one regardless of a difference between sizes, in a paper feeder. SOLUTION: A first paper feed roller 31A and a first friction member 33A, juxtaposed in a position for a fed cut sheet 11 of all size to pass through, a second paper feed roller 31B and a second friction member 33B, juxtaposed in a right/left symmetrical position of the first paper feed roller 31A for the cut sheet 11 of prescribed size or more to pass through, are provided. Only when the cut sheet 11 is in the prescribed size or more, the second paper feed roller 31B and the second friction member 33B can be balanced in cooperation with the first paper feed roller 31A and the second friction member 33A.

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 a cut-out sheet to be fed and is displaced, thereby preventing double feeding. It is used for feeding a recording sheet or a document in a printer, a facsimile, or the like, feeding a document for an image reading apparatus, and in various other 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. 9, 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. When the sheet feed roller c comes into contact with the entire width of the leading end of the cut sheet b that is fed out each time the sheet feed roller c makes one rotation and resists the urging of the restoring spring f, as shown by the imaginary line in FIG. The fed cut sheet b is separated into individual sheets by frictional contact 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 b of the cut sheet is set in a range of 85 to 55 degrees so that the friction member e can be surely separated by the friction.

The above publication also discloses a friction member made of an elastic sheet provided with its lower end fixed under the same angle conditions as described above.

[0005]

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.

However, the friction member e disclosed in the above publication is
A flat friction surface works uniformly over the entire width of the leading end of the cut sheet b to be fed. For this reason, if the conditions are set such that the cut sheet c having a small size can exhibit sufficient separation characteristics, the separation characteristics of the cut sheet c having a large size become excessive, and it is difficult to feed out the cut sheet c, which results in poor sheet feeding. On the other hand, if the separation characteristics are set to be suitable for a large cut sheet c, a problem is likely to occur in that the small cut sheet c lacks the separation characteristics and causes double feeding.

An object of the present invention is to provide a sheet feeding device capable of stably feeding cut sheets one by one regardless of a difference in size.

[0008]

In order to achieve the above object, according to the present invention, there is provided a sheet feeding device comprising: a sheet feeding roller which comes into contact with a stacked cut sheet from one side thereof and sequentially feeds the cut sheet; , The cantilever friction that separates the cut sheets one by one by frictional contact when the cut sheets extend from the other side of the loaded cut sheet to the cut sheet payout path and come into contact with the leading end of the cut sheet and are pushed away. A first sheet feed roller and a first friction member provided in parallel with a position through which cut sheets of all sizes to be fed pass, and a first sheet feeder through which cut sheets of a predetermined size or more pass.
A second paper feed roller and a second friction member provided in parallel with the left and right symmetrical positions of the paper feed roller.

In such a configuration, the first sheet feeding roller and the first friction member are positioned at the center of the second sheet feeding roller and the second friction member at the left and right positions through which a cut sheet having a predetermined size or more passes. In this case, the cut sheets of various sizes smaller than or equal to the predetermined size work uniformly at the center position thereof, and the cut sheets are fed out by the first feed roller and pass while pushing away the first friction member. By the feeding force and the separation characteristics set sufficiently for cut sheets smaller than a predetermined size due to frictional contact, cut sheets smaller than a predetermined size can be reliably separated and fed one by one. It is possible to apply this feeding force and separation characteristics to cut sheets of a prescribed size or more while moving them to the left and right positions for cut sheets of a prescribed size or more. Since the second paper feed roller and the second friction member provided also work, they compensate for the feeding force and the separation characteristic that are large in size and are insufficient with only the first paper feed roller and the first friction member. The left and right sides can share the unwinding force and separation characteristics and work in a well-balanced manner.
It is also possible to solve the problem that the cut sheet is skewed because the feeding force and the separation characteristics are not balanced between right and left, and stable feeding performance is achieved for cut sheets of various sizes.

When the second friction member is located at a position closer to the center of the cut sheet than the second paper feed roller, the second friction member swings greatly from the center position of the cut sheet having a predetermined size or more. , It is easy to hinder the progress of the cut sheet, but it corresponds to the position closer to the center than the second paper feed roller, that is, the left and right range where the cut sheet is forcibly fed out by the left and right second paper feed rollers Position, so that the cut sheet can advance while reliably pushing away the second friction member, and by being located at a position greatly shaken from the center position, it is possible to reliably prevent the sheet feeding or skew. Can be prevented.

Further, when the cut sheet fed out by the paper feed roller is smaller than a predetermined size passing through the inside of the second paper feed roller, the second sheet positioned closer to the center side than the second paper feed roller. If a retracting unit for retracting the friction member from the feeding path is provided, when a cut sheet having a size smaller than a predetermined size is fed, the cut sheet comes into contact with the second friction member and the separation characteristic becomes excessive. Can be prevented.

According to a fourth aspect of the present invention, there is provided a paper feed roller which feeds and sequentially feeds a cut sheet stacked thereon from one side thereof, and feeds the cut sheet from the other side of the stacked cut sheet. A cut sheet of all sizes to be fed, including a cantilevered friction member that separates the cut sheets one by one by frictional contact when the cut sheet extends and extends in the feeding path and comes into contact with and is pushed away. A first paper feed roller and a first friction member provided at a position where the sheet passes, and a second paper supply roller and a second friction member provided at a position where a cut sheet having a predetermined size or more passes. The second friction member is located closer to the center of the cut sheet than the second paper feed roller.

In such a configuration, the first sheet feeding roller and the first friction member work without shortage for the cut sheet smaller than the predetermined size, so that the sheet can be reliably separated and fed one by one. For a cut sheet of a predetermined size or more, the second sheet feeding roller and the second friction member act in addition to the first sheet feeding roller and the first friction member, and the size of the first sheet is large. The feed-out force and the separation characteristic, which are sufficient to compensate for the shortage of the feed-out force and the separation characteristic only by the paper roller and the first friction member, can be used, so that the feed-out force and the separation characteristic do not become excessive. By applying the paper feeding force to the two or more points separated by the rollers in the width direction of the cut sheet, it is possible to prevent the cut sheet from skewing.
Since the second friction member acts at a position greatly shaken from the center position of the cut sheet having a predetermined size or more, it is easy to hinder the advance of the cut sheet, but the position closer to the center side of the cut sheet than the second sheet feed roller, That is, since the cut sheet is positioned corresponding to the left and right range where the cut sheet is forcibly fed by the first and second square sheet feed rollers, the cut sheet can advance while reliably pushing away the second friction member,
By being located far from the center position, it is possible to reliably prevent paper feed from being obstructed or skewed,
Demonstrate stable paper feeding performance for cut sheets of various sizes.

In this case as well, when the cut sheet fed by the paper feed roller has a size passing through the inside of the second paper feed roller, by providing a retracting means for retracting the second friction member from the feed path, it is possible to provide a predetermined means. When a cut sheet smaller than the size is fed, it is possible to prevent the second friction member from abutting on the second friction member, resulting in an excessive separation characteristic, thereby preventing a problem that causes a feeding failure.

[0015]

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

(Embodiment 1) Embodiment 1 is shown in FIGS.
FIG. 6 illustrates a case of a sheet feeding device 1 that feeds a recording sheet by a copying machine as illustrated 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.
4 and 5, left and right side guides 22 provided on the sheet feed tray 21 as shown in FIGS.
Can be adjusted in accordance with the width of the cut sheet 11. The left and right side guides 22 are the paper feed tray 21
The cut sheet 11 of any size is interlocked by an interlocking gear 23 provided therein, so that the cut sheet 11 is fed in a so-called centering type, in which the center is adjusted to the same position.

Such a manual paper feeder 1 includes a postcard,
Various cut sheets 11 other than paper, for example, 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 paper feeder 1 is an auxiliary device that is used less frequently, and a small and simple paper feed mechanism is desired. On the other hand, paper feed performance that can handle various cut sheets 11 is required. In the first embodiment, as shown in FIG. 1, FIG. 2, and FIG. 5, the paper feed device 1 is pushed away by the cut sheet 11 fed by the paper feed roller 31 while the frictional contact at that time is performed. Thus, a simple separation system using a friction member 33 that hinders the advance of the next lower cut sheet 11 to be double-fed to the outermost cut sheet 11 is used, and the various cut sheets 11 are also stable. The paper feeding performance can be demonstrated. 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 the copying machine main body 10 side, and as shown in FIG.
The first feed roller 31A is located at the center in the left-right direction of the feed path 30 fed from the first feed roller 30, and the first feed roller 31A is arranged so that the cut sheet 11 having a predetermined size or more passes.
Paper feed roller 31B located at the left-right symmetric position with respect to
Are provided.

The first sheet feeding roller 31A passes through the central position of the cut sheet 11 of various sizes.

The paper feed tray 21 of the paper feeder 1 has a base 35 having an outer guide 35 of a paper passage 34 for receiving the cut sheet 11 fed from the paper feeder 16 and moving the cut sheet 11 toward the photosensitive drum 7. It extends slightly diagonally upward from 36,
The base 36 is hinged to the copier main body 10 at a side (not shown), and the paper passage path 34 can be opened and closed for jam clearance or the like by rotating integrally with the paper feed tray 21 about the hinge connection part. .

The feed tray 21 has a push-up plate 26 pivotally supported at its rear end by a shaft 24 and 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. When the paper is not fed, its notch faces the cut sheet 11, and when the paper is fed, it is rotated once and its outer peripheral portion has no cut. The cut sheet 1 is sent 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. 11 is largely separated from the paper feed roller 31, and only when the paper is not fed, the cut sheet 1
1 can be easily loaded or pulled out by hand.

When the paper feed roller 31 starts rotating at the time of paper feeding, the cam 31b is disengaged from 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 of the first embodiment is made of an elastic sheet material, and when the cut sheet 11 is fed out by the paper feed roller 31, it is elastically deformed and deformed and pushed away. The cut sheets 11 are separated one by one, and the sheet feed roller 31 contacts the uppermost surface of the stacked cut sheets 11 and feeds out the sheet. The cut sheet 11 extends from the lowermost side of the sheet 11 to the feeding path 30 of the cut sheet 11.

The friction member 33 includes the first paper feed roller 3
A first friction member 33A provided at the same position as or close to 1A, and a second friction member 33B provided at the same position as or close to the second paper feed roller 31B.
Are provided. The first friction member 33A is provided in a cantilevered state as shown in FIG. 5 in which the lower portion is fixed to a support wall 37 rising under the feeding path 30 by an appropriate method such as bonding or screwing. Second friction member 33B
Is located closer to the center than the second paper feed roller 31B as shown in FIG. 2, and is separated by a slide guide 61 shown in FIGS. 1, 3, and 5 from the separation position shown by the solid line in FIG. It is provided in the sheet feeding cassette 21 while being held so as to be able to advance and retreat to and from the retracted position shown. The slide guide 61 is fixed to a predetermined position by, for example, being screwed to the sheet cassette 21 with a screw 63.

Further, the second friction member 33B has a cam follower 62 which engages with a cam groove 22a provided in the left and right side guides 22, and the side guide 22 positions the side of the cut sheet 11 having a predetermined size or more. For example, when moving to the solid line position in FIG. 2, the cam groove 22a advances to the separation position, and the side guide 22 positions the side of the cut sheet 11 smaller than a predetermined size. For example, when the side guide 22 moves to the broken line position in FIG. To be retreated. As a result, the second friction member 33B is at the separation position and acts on the cut sheet 11 only when the cut sheet 11 having a predetermined size or more is fed to exhibit the separation characteristics.

Here, the mechanism of separation by the friction member 33 will be considered. The actual separating mechanism is a combination of the movement in which the cantilevered friction member 33 is pushed away by the cut sheet 11 and the partial buckling of the cut sheet 11. This will be described below in principle and qualitatively for the sake of simplicity.

Now, as shown in FIG. 7A, a condition is considered in which the cut sheet 11 which is to be advanced by the force F receives a frictional force on the friction surface 33a of the friction member 33 and is balanced.
Mu _B coefficient of friction with respect to the cut sheet 11 of the friction surface 33a of the friction member 33, when the contact angle theta (fixed value in this case), when Fcosθ = μ _B · Fsinθ ...... (1), because commensurate, mu _B · tan .theta <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 FIG. 6 (b).

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, the cut sheet 1
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 in order to loosen 1. That is, separation by the friction member 33 means to drive the contact angle θ of only the outermost cut sheet 11 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 in close contact with the outermost surface. It is considered that there is almost no difference in the angle θ.

While the friction member 33 is pushed away by the cut sheet 11 fed out by the paper feed roller 31, the frictional contact at that time causes the cut sheet 11 on the outermost surface to move below the next lower rank as shown in FIG. Buckled larger than the cut sheet 11, and the cut sheet 1 on the outermost surface
1 so that the contact angle θ of the first cut sheet 11 is significantly smaller than the contact angle θ of the cut sheet 11 at the next position or lower, and the cut sheet 11 is separated into individual sheets.
Only the cut sheet 11 passing therethrough and the next lower cut sheet 11 is stopped to prevent double feeding.

However, in practice, the cut sheet is easy to bend depending on the paper quality and thickness, that is, the strength of the stiffness is different, and the cut sheet 11 fed out by the feed roller 31 is moved by the friction member 33. It is difficult to reliably separate and handle without undergoing residual deformation.

In the first embodiment, the friction member 33 is made of, for example, a polycarbonate film, and has a thickness of about 200 μm, which is a commercially available product, so that a suitable restoring force for loosening the cut sheet 11 can be obtained. The friction surface 33a has a necessary friction coefficient obtained by coating the surface of the polycarbonate film with a material having a large friction coefficient such as urethane resin. The coating is preferably by silk screen printing. The heat treatment was performed at about 200 mesh at 80 ° C. for about 30 minutes. The friction surface 33a preferably has a static friction coefficient of about 1.0 to 1.5 with respect to general high-quality paper. Also, the friction surface 33a
Between the angle and the outermost cut sheet 11 is 90 degrees to 1
Preferably, it is set to 20 degrees. The arrangement of the first and second paper feed rollers 31A and 31B and the first and second friction members 33A and 33B is used in combination.

As a result, the first sheet feeding roller 31A and the first friction member 33A are moved to the second sheet feeding roller 31B at the left and right positions through which the cut sheet 11 having a predetermined size or more passes.
And a cut sheet 11 of various sizes smaller than or equal to or larger than a predetermined size at a central position of the second friction member 33B.
Work uniformly on the center position of
1 is fed out by the first paper feed roller 31A, and the first
The cut sheet 11 having a size smaller than the predetermined size is provided one by one by the feeding force and the separation characteristic set to be sufficient for the cut sheet 11 having a size smaller than the predetermined size by the frictional contact when the friction member 33A passes while displacing the friction member 33A. Paper can be reliably separated. In addition, the feeding force and the separation characteristics of the cut sheet
Similarly, the second sheet feed roller 31B and the second friction member 33B provided at the left and right positions also work on the cut sheet 11 having a predetermined size or more while operating the same for the first sheet.
Since these are large in size, the feeding force and the separation characteristic sufficient to compensate for the feeding force and the separation characteristic which are insufficient with only the first paper feed roller 31A and the first friction member 33A are shared on the left and right, so that they work in a well-balanced manner. , The feeding force and the separation characteristic become excessive, and the feeding force and the separation characteristic are not balanced between the left and right, and the cut sheet 11 is not removed.
Can be eliminated, and stable sheet feeding performance can be achieved for cut sheets 11 of various sizes.

When the second friction member 33B is located at a position closer to the center of the cut sheet 11 than the second paper feed roller 31B, the second friction member 33B is moved to a position of the cut sheet 11 having a predetermined size or more. Since it works at the position greatly shaken from the center position, it is easy to hinder the advance of the cut sheet 11, but the second
The cut sheet 11 is forcibly fed out by a position closer to the center side than the sheet feeding roller 31B, that is, the left and right second sheet feeding rollers 31B and 31B, and the first sheet feeding roller 31A therebetween. Since the cut sheet 11 is positioned corresponding to the left and right ranges, the cut sheet 11 can advance while reliably pushing and retreating the second friction member 33B. It is possible to reliably prevent the sheet from being dropped, and the sheet feeding performance is further improved. Further, since the second friction member 33B arranged in this manner is separated from the second paper feed roller 31B, the first friction member 33B which is not separated from the first paper supply roller 31A is used.
As compared with the friction member 33A, the separation characteristic is weakened by an amount that the cut sheet 11 easily escapes. However, in the first embodiment, the first friction member 33A and the material, thickness, length,
By setting the installation conditions to be the same and narrowing the width, the separation characteristics are prevented from becoming excessive. However, such adjustment can be performed by setting various parameters including the state of the friction surface 33a in various ways.

Further, when the cut sheet 11 fed by the feed roller 31 is smaller than a predetermined size passing through the inside of the second feed roller 31B, the cut sheet 1
When the side guide 22 is moved to position the first side, the side guide 22 becomes the retracting means 63 and the second
Automatically retracts the second friction member 33B located closer to the center side than the paper feed roller 31B from the feeding path 30 via the cam groove 22a and the cam follower 62, so that the cut sheet 11 having a size smaller than the predetermined size is used. When the sheet is fed, it is possible to prevent a problem that the sheet comes into contact with the second friction member 33B so that the separation characteristic becomes excessive and causes a sheet feeding failure.

When the side guide 22 is moved to a position for positioning the side of the cut sheet 11 having a predetermined size or more, the second guide is moved through the cam groove 22a and the cam follower 62.
Is advanced to the separation position, so that the cut sheets 11 having a predetermined size or more can be operated so as to be separated one by one.

When the means for retracting the second friction member 33B is mechanically linked to the movement of the side guide 22, the structure is simple and the operation is reliable. However, the present invention is not limited to this. The position of the side guide 22 is electrically detected, and an electric actuator for moving the second friction member 33B forward and backward is operated based on the detection signal. Can also.

Also, in the first embodiment, the paper feeder 1 of the top-up type has been described. However, the present invention is similarly applied to a type of paper feed-down type only by making the configuration upside down. Can be. Also, the center alignment method has been described. However, if there are a plurality of paper feed rollers 31, skew hardly occurs even if the cut sheet 11 acts on a biased position. Can be applied. In any case, the first paper feed roller 31
A and a plurality of at least one of the second friction member 33A may be provided.

In the case of the one-side reference, the first feed roller 31A and the first friction member 3 of the first embodiment are used.
3A is provided at a position where cut sheets 11 of various sizes pass, and one of the second paper feed roller 31B and the second friction member 33B of the first embodiment is provided at a position where a cut sheet 11 having a predetermined size or more passes. But cut sheet 1
According to the size of 1, the paper can be stably fed without any excess or deficiency in the separation function and no skew. Further, the present invention is similarly applicable to a case where the friction member 33 is of a type whose base is pivotally supported by a shaft and a restoring force is given by the bias of a spring.

(Embodiment 2) In Embodiment 2, as shown in FIG. 8, the side guides 22 define a solid line position for positioning a side of a cut sheet having a predetermined size or more, and a side of a cut sheet having a size smaller than a predetermined size. In conjunction with the movement between the broken line position to be positioned, the second friction member 33B is moved to a separation position shown by a solid line and to a retreat position retracted from the feeding path 30 while being inclined sideways as shown by a broken line. Although the type of the retreat operation is different from that of the first embodiment, the same operation and effect as those of the first embodiment can be achieved. Note that the disclosure of specific interlocking means is omitted. The retraction of the second friction member 33B from the feeding path 30 may be performed by tilting the second friction member 33B in the sheet feeding direction, or any specific method or means may be used as long as the second friction member 33B can be retreated from the feeding path 30.

[0046]

According to the present invention, cut sheets having different sizes can be easily and reliably separated one by one without excessive or insufficient separation characteristics due to the difference in size.
Paper can be fed stably without skewing or the like.

[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 plan view of a main part of the sheet feeding device of FIG. 1;

FIG. 3 is a cross-sectional view schematically illustrating a retracting unit of a second friction member in a main part of the sheet feeding device of FIG.

FIG. 4 is a plan view of the retracting means of FIG. 3;

FIG. 5 is a sectional view showing the entire sheet feeding device of FIG. 1;

FIG. 6 is a schematic configuration diagram of a copying machine having the sheet feeding device of FIG. 5;

FIGS. 7A and 7B are explanatory views illustrating the principle of separation of cut sheets by a friction member to which the present invention is applied. FIG.
(B) is a graph which shows the boundary conditions of a stop and advancing when a cut sheet contacts a friction member.

FIG. 8 is a plan view of a main part showing the second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a main part 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 22 Side guide 22a Cam groove 26 Push-up plate 30 Feeding path 31 Paper feed roller 31A First paper feed roller 31B Second paper feed roller 33 Friction member 33a Friction surface 33A First friction member 33B Second friction member 37 Support wall 61 Slide guide 62 Cam follower

Claims (5)

[Claims] A sheet feed roller which comes into contact with the loaded cut sheet from one side thereof and sequentially feeds the cut sheet; and a feed roller which extends from the other side of the loaded cut sheet to a cut sheet feeding path and feeds the cut sheet. In a sheet feeding device having a cantilevered friction member that separates the cut sheets one by one by frictional contact when the sheet comes into contact with the leading end portion and is pushed away, a position where cut sheets of all sizes to be fed pass is provided. The first paper feed roller and the first friction member provided side by side and the second paper feed roller and the second paper feed side provided at the left-right symmetric position of the first paper feed roller through which a cut sheet having a predetermined size or more passes.
And a friction member. 2. The sheet feeder according to claim 1, wherein the second friction member is located closer to the center of the cut sheet than the second sheet feed roller. 3. A retracting means for retracting a second friction member from a feeding path when a cut sheet fed by the feeding roller is smaller than a size passing through the inside of the second feeding roller. Paper feeder as described. 4. A sheet feed roller that comes in contact with a loaded cut sheet from one side thereof and sequentially feeds out the cut sheet, and a cut sheet that extends from the other side of the loaded cut sheet to a cut sheet feed path and is fed out. In a sheet feeding device having a cantilevered friction member that separates the cut sheets one by one by frictional contact when the sheet comes into contact with the leading end portion and is pushed away, a position where cut sheets of all sizes to be fed pass is provided. A first paper feed roller and a first friction member provided side by side; and a second paper supply roller and a second friction member provided side by side at a position where a cut sheet having a predetermined size or more passes. A paper feeder, wherein the friction member is located closer to the center of the cut sheet than the second paper feed roller. 5. A retracting means for retracting the second friction member from the feeding path when the cut sheet fed by the feeding roller is smaller than the size passing through the inside of the second feeding roller. Paper feeder as described.