JPH09110181A - Paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feed device capable of hardly generating jam, skew, and the like, and reducing transcription blurring and generation of paper powder, although this device is constituted simply and at a low price. SOLUTION: This paper feed device is provided with a paper sheet loading part 12 having a push-up plate 11 loading a paper sheet P, a paper feed roller sending out the paper sheet P, an elastic member pushing up the push-up plate 11 from the lower side and pressing the paper sheet on the paper feed roller side, and a pair of side guide members 15-1, 15-2 guiding the width direction of the paper sheet, and projecting parts 17-1, 17-2 regulating the width direction of the paper sheet are provided on the inside of the front end parts in the paper sheet feeding direction of the side guides. The paper sheet regulating width by the projecting parts is made narrower than the width of the paper sheet, and only the paper sheet on the uppermost position is separated one by one while bending both ends by the feed of the paper feed roller.

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 feeding stacked sheets while separating them one by one, and is applicable to, for example, a plain paper copier (PPC), a facsimile, a printer, and the like. is there.

[0002]

2. Description of the Related Art Conventionally, a corner claw separation method and a friction pad separation method have been mainly used as an inexpensive paper feeding method in an image forming apparatus or the like.
There are drawbacks, and various measures have been taken to improve the drawbacks. As a result, there is a problem that the structure becomes complicated and the cost increases. Besides that, there is still room for improvement.

[0003]

For example, the corner claw separation method has a simple structure and is excellent in durability, but the paper in the tray is disengaged from the claws by the impact when the tray is set in the image forming apparatus or the like. It often causes jam, skew, etc.

Further, in the friction pad separation system, a large load is applied at the time of paper feeding, a large back tension is applied to the roller on the downstream side in the paper feeding direction, the position of the paper is varied, and transfer blur occurs, or the friction pad is used. Paper dust is often generated due to friction between paper and paper, and countermeasures against it are desired.

The present invention has been made in view of the above problems of the prior art, and in a sheet feeding device such as an image forming apparatus that feeds stacked sheets while separating them one by one, side guide sheet feeding A protrusion that restricts the width direction of the sheet is provided inside the front end in the direction, the sheet regulation width by the protrusion is made narrower than the sheet width, and both ends of the uppermost sheet are bent by feeding the sheet feeding roller. An object of the present invention is to provide a paper feeding device that has a simple and inexpensive configuration by separating the sheets one by one, and is less likely to cause jams, skews, etc., and reduce transfer blur and paper dust generation. To do.

Further, according to the present invention, when the loop of the paper is formed at the protruding portion inside the front end of the side guide, the side guide opens outward due to rattling of the side guide and the tray and the width of the paper is regulated. The size of the loop may vary, and this phenomenon makes it difficult to form a proper and stable loop on the paper, which may cause double feed. An object of the present invention is to provide a paper feeding device capable of preventing feeding.

Further, according to the present invention, when the loop of the paper is formed at the protrusion inside the front end of the side guide, the separation load changes between the thick paper and the thin paper. When the regulation width of is set, the load may become too large and may not feed when thick paper is used.If the regulation width of paper is set according to the thick paper, the load becomes too small when the paper is thin. Since double feeding is likely to occur, it is possible to give separation and addition according to the thickness of the paper, and whether the paper is thick or thin, it will not be fed. An object of the present invention is to provide a paper feeding device that does not cause double feeding.

Further, in recent years, as a paper feed tray for printers, PPCs and the like, a universal type which can support various kinds of paper sizes is mainly used. Since the side guides are separated, the side guides must be lengthened in the paper direction, and if the side guides are moved according to the paper size, there is a problem that they interfere with the bottom plate. Therefore, an object of the present invention is to provide a so-called universal type sheet feeding device in which the side guide and the bottom plate do not interfere with each other even when the side guide is moved according to the sheet size. .

[0009]

In order to solve the above problems, the invention according to claim 1 includes a paper stacking section having a push-up plate for stacking paper, a paper feed roller for sending out the paper, and the push-up plate. It has an elastic member that pushes up the paper from the lower side and presses the paper toward the paper feed roller, and a pair of side guide members that guide the width direction of the paper, and the width of the paper is inside the front end of the side guide in the paper feeding direction. The present invention is characterized in that a projecting portion for regulating the direction is provided, a sheet regulation width by the projecting portion is made narrower than the sheet width, and only the uppermost sheet is separated by sheet feeding while being bent at both ends by feeding of a sheet feeding roller. .

According to a second aspect of the present invention, in the sheet feeding device, the inside of the front end portion of the side guide member in the sheet feeding direction is wide at the lower side in the sheet stacking direction and gradually narrows at the upper side. Characterize.

According to a third aspect of the present invention, in the sheet feeding device, the protrusion of the front end portion of the side guide member in the sheet feeding direction is formed of an elastic member.

According to a fourth aspect of the present invention, in the paper feeding device, the side guide member is movable in a direction orthogonal to the paper feeding direction.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments for carrying out the present invention will be described below. However, the present invention is not limited to this.

(First Embodiment) FIGS. 1 and 2 schematically show a copying apparatus according to the present embodiment. In these drawings, the paper feeding device 10 according to the present embodiment is a paper P
A sheet stacking section 12 having a bottom plate 11 as a push-up plate for stacking sheets, a sheet feed roller 13 that sends out the sheet P in the sheet feeding direction (X direction), and an axial hole 1 formed in the sheet stacking section 12.
2a as a center, the bottom plate 12 is rotated and pushed up from below to press the paper P toward the paper feed roller 13, and a pressure spring 14 as an elastic member, and a pair of side guide members for guiding the paper P in the width direction. And side fences 15-1 and 15-2, and an end fence 16 that regulates the rear end position of the paper P. In the side guides, the protrusions 17 that face each other inside the front end of the paper P in the paper feeding direction X and in the tangential direction on both sides of the paper.
-1, 17-2 are provided. This pair of protrusions 1
7-1 and 17-2 are for restricting the width direction of the paper P, and the width d1 for restricting the paper P by the pair of protrusions 17-1 and 17-2 is smaller than the paper width d2. . By feeding the paper feed roller 13, only the uppermost sheet P1 of the stacked sheets P can be separated one by one while bending both ends.

In this embodiment, the pressure spring 14 is used as the elastic member for pressing the paper P toward the paper feed roller 13, but the present invention can use other pressing means. It is not limited to the embodiment.

Next, the operation of the above embodiment will be described with reference to FIGS. In the embodiment shown in FIGS. 1 and 2, the protrusions 17-1 and 17-2 at the front end portions of the side guides 15-1 and 15-2 in the sheet feeding direction serve as the side guides 15-1 and 15-2. Although it is bulged inward, in the embodiment shown in FIGS. 3 to 5, the projections of the side guides 15-1 and 15-2 at the front end in the paper feed direction are bent inward. Bent portions 18-1, 1 formed by
The difference is that it is composed of 8-2. However, the protruding portions 17-1 and 17-2 and the bent portions 18-1 and 1
8-2 can be considered to be substantially the same in terms of configuration and function, so the operation of the above-described embodiment will be described with reference to FIGS. 3 to 5.

FIG. 3 shows a set state of paper. First,
As shown in FIG. 3, in this embodiment, the side guide 1
Bent portions 18-1, 18 as protrusions so that the tips of 5-1 and 15-2 are on the inner side of the extension line of the side guide.
-2 is formed, and the stacked sheets P are set on the front side thereof.

By the rotation of the paper feed roller 13, the paper feed roller 13 and the paper P come into contact with each other, and the paper P is fed in the paper feed direction X of the paper P. 1
The opposing width d1 of 5-2 is the paper width d2 in the paper feeding direction X.
Becomes narrower. Therefore, the bent portion 18-
When the leading edge of the sheet P reaches the portions 1 and 18-2, the uppermost sheet P1 bends in a loop at both ends, and only the uppermost sheet is separated sheet by sheet (see FIG. 5).

As described above, according to the embodiment shown in FIGS. 1 to 5, the protrusion 17 for regulating the width direction of the sheet is provided inside the front end portions of the side guides 15-1 and 15-2 in the sheet feeding direction. -1, 17-2 or bent portion 18 as a protruding portion-
1 and 18-2 are provided, and the sheet regulation width due to these protrusions or bends is made narrower than the sheet width, but both ends of the uppermost sheet P1 are formed by these protrusions or bends. It is possible to obtain a paper feeding device that can be bent in a loop shape, whereby jams, skews, and the like are less likely to occur, and transfer blurring and paper dust generation can be reduced. Further, by making the paper feed roller 13 a half-moon roller, the frictional load on the paper feed unit after paper feed is reduced, and stable paper feed performance can be obtained.

The conditional expression of the paper feeding method of the present invention is as follows. <Conditional Expression> 1) Feeding condition for the first sheet P1 (μPR-μPP1) × P> R 2) Feeding condition for the second sheet P2 (μPR1-μPP2) × P <R where P: feed Paper pressure μPR: Coefficient of friction between paper feed roller and paper μPP1: Coefficient of friction between paper sheets (first and second sheets) μPP2: Coefficient of friction between paper sheets (second and third sheets) (μPR1-μPP2) : Variation of friction coefficient between paper (ΔμPP) R: Load of side guide (where paper guide width is narrow) for paper

Second Embodiment Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 shows the configuration of the second embodiment of the present invention, in which the cross-sectional shape of the front end portions of the side guides 25-1 and 25-2 on both sides in the sheet feeding direction becomes narrower on the upper side, so-called tapered shape. Has become. That is, the side guide 25
The front end portions of the sheet feeding directions −1 and 5-2 are wide on the lower side in the sheet stacking direction and gradually narrow toward the upper side.

Now, the conventional paper feeder shown in FIG. 7 will be examined. As shown in FIG. 7, the side guide 05-
The side guide 05-
When 1,05-2 is opened to the outside, there is no restriction in the width direction of the paper P, a loop is not formed, and it becomes difficult for the paper to be separated, which causes double feeding, and the paper edge gets over the side guide. As a result, skew or jam may occur.

On the other hand, as in the embodiment of the present invention shown in FIG. 6, side guides 25-1 and 25-2 on both sides are provided.
By tapering the cross-sectional shape of the front end portion of the paper feed direction, when the paper is fed by the paper feed roller 13, the paper P
Both sides can be reliably regulated, a stable sheet loop can be formed at the time of separation, and the occurrence of double feeding, skew, jam, etc. can be eliminated.

(Third Embodiment) Next, the third embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. As shown in FIG. 8, in the third embodiment, the side guide 35-
Leaf springs 37-1 and 37-2 facing each other are provided as protruding portions inside the front end portions of the sheet feeding directions 1 and 35-2 in the sheet feeding direction. Also, the same operation as that of the second embodiment is performed.

When the paper is thick paper, the spring force of the leaf springs 37-1 and 37-2 is such that, when the thick paper comes into contact with the thick paper, it flexes slightly due to the stiffness of the thick paper. This prevents the separation load from becoming excessive in the case of thick paper as compared with the case of thin paper.

FIG. 9 shows the relationship between separation load and paper thickness. In FIG. 9, the line connecting the black circles shows the case of the first embodiment, and the line connecting the white circles shows the case of the present embodiment. As can be seen from FIG. 9, according to the first embodiment, the separation load relatively rapidly increases as the paper thickness increases, and in the case of thick paper, the separation load tends to become excessive. According to the third embodiment, as the paper thickness increases, the separation load also increases, but as the paper thickness increases, the leaf springs 37-1 and 37-2 bend and the regulation width for the paper expands. The separation load does not become excessive, and the separation load is appropriate according to the paper thickness. Therefore, from thin paper to thick paper,
It is possible to give a separation load suitable for each, double feed,
It is possible to eliminate the occurrence of skew and jam.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. As shown in FIG. 10, the side guides 45-1 and 45-2 are provided with escape holes 45a and 45b of the sheet placement plates 11-1 and 11-2 which are projected to both sides of the front end of the bottom plate 11 in the sheet feeding direction. Is provided. Thereby, the side guides 45-1, 4
Even when 5-2 is moved in the paper feeding direction X and the direction Y orthogonal thereto, the interference between the side guides 45-1 and 45-2 and the bottom plate 11 is eliminated, and the invention of the first aspect described above is eliminated. It is possible to realize universality in the paper feeding method.
The side guides 45-1 and 45-2 also have protrusions 46-1 and 4 inside the front end portion in the sheet feeding direction, which have the same configuration and function as the protrusions in the first embodiment.
6-2 is formed.

The escape holes 45a and 45b formed in the side guides may be formed above the side guides 45-1 and 45-2, as shown in FIG.

[0029]

According to the first aspect of the present invention, the side guide is provided inside the front end portion in the sheet feeding direction with a protrusion for regulating the width direction of the sheet. Although it is a simple and inexpensive structure that is narrower than the width of the paper, both ends of the uppermost paper can be bent in a loop shape by these protrusions, which prevents jams, skews, etc. It is possible to obtain a paper feeding device that can reduce the generation of paper dust. In addition, since the separation claw unlike the conventional corner claw method is not required, the paper claw detachment at the time of tray setting is eliminated,

According to the second aspect of the present invention, since the protruding portion of the tip portion of the side guide is tapered in the vertical direction, both sides of the upper sheet are fed when the sheet is fed by the sheet feeding roller. It is possible to surely regulate, and it is possible to form a stable sheet loop at the time of separation, and it is possible to eliminate double feed, skew, jam, and the like.

According to the third aspect of the present invention, since the protruding portion at the tip end portion of the side guide is made of an elastic member such as a leaf spring, the leaf spring bends in accordance with the paper thickness and has a proper degree in accordance with the paper thickness. The separation load can be obtained, and even if the paper thickness changes, the occurrence of double feeding, skew, jam, etc. can be eliminated.

According to the fourth aspect of the present invention, the side plate is provided with a clearance for the bottom plate, and the side guide member is movable in the direction orthogonal to the paper feeding direction. It is possible to deal with various paper sizes while eliminating the occurrence of jams and the like.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of a paper feeding device according to the present invention.

FIG. 2 is a perspective view of the above-described first embodiment.

FIG. 3 is a plan view showing another embodiment of the paper feeding device according to the present invention.

FIG. 4 is a plan view showing an operating state of the above embodiment.

FIG. 5 is a front view showing still another embodiment of the paper feeding device according to the present invention.

FIG. 6 is a front view showing still another embodiment of the paper feeding device according to the present invention.

FIG. 7 is a front view showing an example of a conventional paper feeding device.

FIG. 8 is a perspective view showing still another embodiment of the paper feeding device according to the present invention.

FIG. 9 is a diagram showing a comparison of the relationship between the paper thickness and the separation load in the same embodiment and the first embodiment.

FIG. 10 is a perspective view showing still another embodiment of the paper feeding device according to the present invention.

FIG. 11 is a perspective view showing still another embodiment of the paper feeding device according to the present invention.

[Explanation of symbols]

 10 Paper Feeding Device 11 Bottom Plate 12 Paper Stacking Section 13 Paper Feeding Roller 14 Pressure Spring 15-1, 15-2 Side Guide 16 End Fence 17-1, 17-2 Projecting Part

Claims (4)

[Claims] 1. A paper stacking unit having a push-up plate for stacking paper, a paper feed roller for feeding the paper, an elastic member for pushing up the push-up plate from below to press the paper toward the paper feed roller, and A pair of side guide members for guiding the width direction is provided, and a projecting portion for restricting the width direction of the sheet is provided inside the front end of the side guide in the sheet feeding direction.
A sheet feeding device characterized in that a sheet regulation width by the projecting portion is made narrower than a sheet width, and only the uppermost sheet is separated by sheet feeding while being bent at both ends by feeding of a sheet feeding roller. 2. The sheet feeding device according to claim 1, wherein the inside of the front end portion of the side guide member in the sheet feeding direction is wide on the lower side in the sheet stacking direction and gradually narrows on the upper side. Paper equipment. 3. The sheet feeding device according to claim 1, wherein the protrusion of the front end portion of the side guide member in the sheet feeding direction is
A sheet feeding device formed of an elastic member. 4. The paper feeding device according to claim 1, wherein the side guide member is movable in a direction orthogonal to the paper feeding direction.