JP2003155129A - Paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of chattering noise (chattering noise, stick slip noise) which may cause large noise by fine vibration caused when a shaft supporting a pickup roller picks up slight vibration occurring when a paper feed device is operated when paper sheets are taking in the paper feed device and occurs remarkably when a cassette frame pivotally supporting the shaft is made of resin and provides noise to surroundings. SOLUTION: In this paper feed device, a bottom plate 21 is installed in a paper feed cassette through a spring, the shaft 24 is pivotally mounted on the cassette frame over the bottom plate, and the pickup roller 25 is supported by the shaft 24. The device comprises a stopping means 12 coming into contact with the shaft 24 from the upper side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device such as a facsimile machine or a copying machine having a structure in which a paper stored in a paper feeding cassette is fed out by a pickup roller and separated one by one by a separating claw for feeding. .

[0002]

2. Description of the Related Art Conventionally, in a paper feeding cassette for storing paper, a bottom plate for setting the paper is supported by a spring arranged on the pickup roller side for feeding the paper, and both sides of the set paper for feeding are set. 2. Description of the Related Art A sheet feeding device having a structure in which a separation claw that temporarily locks a corner is provided is known. In this paper feeding device, the bottom plate is biased by the spring toward the side closer to the pickup roller. Therefore, when the pickup roller is driven, the uppermost sheet of the sheets placed on the bottom plate comes into contact with the pickup roller formed in a substantially half-moon fan shape and is fed by rotation of the pickup roller. It is fed out while causing a slip. Since the corners of the leading edge of the paper are locked by the separation claws, the center of the paper is bent so as to bulge in a convex shape at the time of feeding, and then the corners are jumped up and separated from the separation claws and arranged on the downstream side. Reached the feed roller. The sheet fed into the feed roller is fed into the press roller and sent out from the paper feed cassette to the downstream side. The pickup roller is
Both ends are supported by shafts mounted and supported by the casing.

[0003]

In the sheet feeding device having such a structure, the shaft supporting the pickup roller vibrates finely and produces a large abnormal noise such as "vibration ..." ) May occur, but it is empirically known that this chattering noise frequently occurs when there is little paper left on the bottom plate of the paper feeding device. There are various possible causes for this occurrence, but it is believed that this occurs due to the balance between the elastic force of the spring that biases the bottom plate and the rigidity of the cassette frame that axially supports the shaft.

That is, in recent years, there has been a tendency to increase the capacity of the paper feed cassette in response to the user's request, and the number of papers capable of holding 500 or more sheets is increasing. In such a large-capacity sheet feeding device, as the number of sheets that can be accommodated increases, a spring having a stronger elastic force is used as a spring for urging the bottom plate of the sheet feeding cassette. It has become to. When the elastic force of the spring increases, a large load is applied to the shaft that supports the pickup roller when the paper is sent by the rotation of the pickup roller, and the shaft is pushed upward. When the shaft bends upward, the spring stretches and the elastic force weakens, and conversely, the force that the bent shaft tries to return to becomes larger, and the shaft returns to the original position. When the shaft returns to its original position, the spring contracts and the elastic force increases, and it tries to push the shaft upward again. As the spring and the shaft repeatedly move up and down in this manner, the shaft and the spring, and the paper feed system members such as the pickup roller and the bottom plate vibrate. Further, by repeating contact and separation between the paper and the pickup roller, a slight chatter vibration is generated.

Further, it may be caused by the following causes. That is, when the cassette frame that pivotally supports the shaft of the sheet feeding device is made of metal, the rigidity of the frame portion is high, so that the shaft is less likely to vibrate and the chattering noise as described above is rarely generated. When the frame part is made of synthetic resin for reasons such as a simplification of the structure and a request for cost reduction, the rigidity of the part that supports the shaft becomes low and the shaft is easily bent. Due to the force, it is difficult to suppress the vertical vibration of the shaft, and a chattering noise may occur.
Specifically, the chattering noise starts to be generated even in a state in which a relatively large amount of about 20 sheets of paper remains on the bottom plate of the paper feeding device. As described above, there is a problem in that a large abnormal noise such as a chattering noise is generated due to the vibration of the sheet feeding system member.

[0006]

The above is the problem to be solved by the present invention, and the means for solving the problem will be described below. First, as described in claim 1, a paper feed cassette including a bottom plate on which recording paper can be placed, a spring for pushing up one end side of the bottom plate, and a pickup roller provided on the free end side of the bottom plate, Further, in the sheet feeding device having the cassette frame to which the sheet feeding cassette can be attached, the cassette frame is provided with a shaft for supporting the pickup roller and a regulating member for regulating the upward movement of the shaft. With such a configuration, the regulating means comes into contact with the shaft to absorb and suppress the vibration of the shaft.

According to a second aspect of the present invention, the regulating member is provided so as to abut on a central portion in the axial direction of the shaft. With this configuration, the restricting unit contacts the axially central portion of the shaft that bends upward in an arcuate shape, prevents the shaft from bending, and effectively absorbs and suppresses vibration of the shaft.

As described in claim 3, the regulating member is made of resin. This reduces the friction generated between the shaft and the restricting means that are in contact with each other.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described.
Description will be given with reference to the facsimile machine 1. 1 is a perspective view of a facsimile device, FIG. 2 is a side sectional view of a paper feeding device, FIG. 3 is an enlarged plan view showing a mounting portion of a vibration regulating member, FIG. 4 is an enlarged side view of the same, and FIG. 5 is an enlarged rear view of the same. , Fig. 6
FIG. 4 is a perspective view of a vibration regulation member. In the following description, for the sake of convenience, the front-back and left-right positions of each structure will be described with the direction of arrow A shown in FIG. 1 as the front (front side) of the facsimile apparatus 1. The same applies to the front-rear and left-right positions of each structure in other drawings.

First, a schematic structure of the facsimile apparatus 1 will be described with reference to FIG. The main body of the facsimile device 1 is placed and fixed on the paper feeding device 2, and the image reading device 3 and the image recording device 4 are vertically arranged in the main body. Above the image reading device 3, an automatic document feeder (hereinafter referred to as “A
DF ") 6 is attached, and an exterior cover 7 is provided above the ADF 6.
Is provided so as to be openable and closable with respect to the main body of the facsimile apparatus 1.

The upper surface of the exterior cover 7 is used as a document discharge tray 10, and a paper feed tray 9 is provided above the discharge tray 10. The originals set on the paper feed tray 9 are separated one by one and taken into the ADF 6, and the image thereof is read by the CCD of the image reading device 3 and then discharged to the discharge tray 10.

The read image is converted into a digital signal (image information) and transmitted to the other party via a telephone line. The image information received from the other party is processed by the image recording device 4 and transferred to the paper taken in from the paper feeding device 2.
Alternatively, the image read by the image reading device 3 can be directly transferred to a sheet by the image recording device 4 without being transmitted (a so-called copy function). Then, the paper is unwound from the image recording device 4 and discharged to a discharge tray 11 provided in a space below the image reading device 3.

Next, the structure of the paper feeding device will be described with reference to FIG. In the paper feeding device 2, the paper feeding cassette 20 having a substantially rectangular parallelepiped shape with an open upper surface is provided with a cassette frame 23.
It is arranged slidably with respect to the sheet feeding cassette 20 so that the sheet feeding cassette 20 can be pulled out from the cassette frame 23. The cassette frames 23 are stacked in a plurality of stages, and the facsimile apparatus main body 1 is placed on the uppermost cassette frame 23.
Is placed and fixed. Although the facsimile apparatus main body 1 and the cassette frame 23 are separately configured in this example, the facsimile apparatus main body 1 and the cassette frame 23 may be integrally configured. A flapper 21, which is a bottom plate for setting paper, is rotatably supported in the paper feed cassette 20.
A spring 14 (not shown) arranged on the side for feeding the paper
It is urged upward by (not shown in FIG. 2). When setting the paper in the paper feed cassette 20, the paper feed cassette 20 is pulled out from the cassette frame 23, a plurality of papers are placed on the flapper 21, and the flapper 21 is rotated upward by the spring 14. Then, the left and right corners of the tip (front end) of the upper surface of the placed paper are pressed against the lower surfaces of the separation claws 22. afterwards,
The paper cassette 20 is pushed into the cassette frame 23 to complete the paper setting.

Pickup rollers 25, 25 are provided above the separating claws 22, 22, and feed rollers 27, 27 ... And press rollers 28, 2 are provided in front of them.
8 ... And are arranged. The pickup rollers 25, 25 are arranged in a pair on the left and right, and are supported by a shaft 24 pivotally supported by the cassette frame 23 above the flapper 21. The pickup roller 25 is formed in a fan shape having a substantially half-moon shape in a side view, and when it makes one rotation, its roller surface comes into contact with the left and right center side of the upper surface of the uppermost sheet of the plurality of sheets set on the flapper 21. Then, the paper is loaded. Since the leading edges of the sheet are regulated by the separating claws 22 and 22, a constant resistance is generated against the feeding, but since the coefficient of friction between the sheets is small, the uppermost layer that contacts the pickup roller 25. Only the sheet of paper is fed while slipping on the other sheets. Initially, the sheet is bent so that the central portion thereof rises in a convex shape while the corners thereof are retained by the separation claws 22 and 22, and then the corners are jumped up from the separation claws 22 and separated. After that, the leading edge of the paper is fed by the feed roller 27 arranged on the downstream side of the pickup roller 25.
・ 27 ... is reached and is fed by the feed roller 27. The paper fed into the feed roller 27 is then fed into the press rollers 28, ..., And fed into the image recording device 4 on the downstream side.

In the sheet feeding device 2 having such a structure, the shaft 2 for supporting the pickup rollers 25, 25
4 picks up a slight vibration that occurs when the sheet feeding device 2 operates (for example, a vibration caused by slipping of sheets at the time of separating sheets, a vibration of the flapper 21), and vibrates finely,
A loud noise such as "vibrate ..." may be generated (chatter sound, stick-slip sound). It is empirically known that this chattering noise frequently occurs when there is not much paper left on the flapper 21 of the paper feeding device 2. There are various possible causes for this occurrence, but the flapper 21
It is considered that this occurs due to the balance between the elastic force of the spring for urging the upper part of the shaft and the rigidity of the portion of the pickup roller 25 that supports the shaft 24.

If the cassette frame 23 that supports the shaft 24 of the sheet feeding device 2 is made of metal,
Since the shaft support portion has high rigidity, the shaft 24 is less likely to vibrate, and the chattering noise described above does not occur so much. Specifically, the chattering noise may occur when the last one sheet remains on the flapper 21 of the sheet feeding device 2 when the last one sheet is picked up. In other cases, it hardly occurs. On the other hand, in the present embodiment, the cassette frame 23 is made of a synthetic resin having low rigidity to reduce the cost. In this case, it is difficult to suppress vertical vibration of the shaft 24 because the portion that supports the shaft 24 is weak in rigidity and easily bends, and as a result, chatter noise is likely to occur. Specifically, the chattering noise starts to be generated when the last 20 sheets of paper remain on the flapper 21 of the paper feeding device 2.
As a result, the chattering noise of “vip ...” continues to be emitted until the last 20 sheets of paper are stacked and the last sheet of paper is rewound, which causes unpleasant noise to surrounding users. It was.

Further, in recent years, there is a tendency that the capacity of the paper feed cassette 20 is increased in response to the user's request, and the number of papers capable of holding 500 or more sheets is increasing. In such a sheet feeding device 2, it is known that a chattering noise is generated due to another cause in addition to the above causes. As the spring 14 for urging the flapper 21 of the large-capacity sheet feeding cassette 20, one having a stronger elastic force is used as the number of accommodated sheets increases. When the number of sheets set on the flapper 21 increases, the spring 14 is compressed and the restoring force increases, and when the full sheet is set, the restoring force by the spring 14 becomes maximum. In particular, when the paper set in the full-paper state is fed, the impact when the substantially half-moon-shaped pickup roller 25 contacts the paper is generated by the compressed spring 14
Is not absorbed so much by the pickup roller 2
5 receives a strong reaction force from the upper surface of the paper set on the flapper 21. Upon receiving this reaction force, the pickup roller 25 is pushed up, whereby both ends of the cassette frame 23
The shaft 24 of the pickup roller 25 pivotally supported on the shaft bends in an arc shape. When the shaft 24 bends in an arc and the pickup roller 25 moves up relatively, the compressed spring 14 tries to expand. As the spring 14 extends, the restoring force of the spring 14 weakens, and the reaction force that the pickup roller 25 receives from the paper on the bottom plate also weakens, and the pickup roller 25 that has been pushed up tries to return to its original position, and the shaft 24 tries to return straight. To do. However, when the shaft 24 returns to its original shape,
The paper on the flapper 21 is pushed down by the pickup roller 25, and the spring 14 is compressed again. With this compression, the restoring force of the spring 14 increases and the reaction force that the pickup roller 25 receives from the paper also increases. The pickup roller 25 is gradually pushed up while receiving this reaction force, and the shaft 24 of the pickup roller 25 bends upward in an arc shape again. These phenomena are repeated while the pickup roller 25 comes into contact with the sheet and is fed out, and the pickup roller 25, its shaft 24,
The flapper 21, the spring 14 and the like vibrate vertically. Further, by repeating contact and separation between the paper and the pickup roller 25, a slight chatter vibration is generated. That is, even when the paper is full, these vibrations can be heard as chattering sounds.

Therefore, in this embodiment, the bearing 13 (shown in FIGS. 3 and 5) for supporting the shaft 24 is made of a flexible material such as polyamide, polyether nitrile, polyoxymethylene, etc. to absorb the vibration. is doing. Furthermore,
The vibration regulating member 12 (shown in FIG. 6), which is the regulating means, is brought into contact with the axially central upper portion of the shaft 24 to suppress bending and vibration of the shaft 24. The vibration regulating member 12 has a shape like "L" inverted upside down in a side view, and the protrusion 12a provided on the upper surface thereof is fitted and fixed in the fitting holes 8a, 8a of the metal plate 8 above the shaft 24. The left and right edges of the lower surface extend downward and are in contact with the circumferential surface of the shaft 24 at the central portion in the axial direction. Vibration regulating member 12
Is attached to the metal plate 8 so as to be in contact with the central portion of the shaft 24 in the axial direction. By thus contacting the shaft 24 from above at the central portion in the axial direction, the shaft is prevented from bending and vibration is effectively suppressed. This is particularly effective in preventing a chattering noise caused by the bending of the shaft when the paper cassette is large in the number of papers stored.

As described above, in order that the contact of the vibration regulating member 12 with the shaft 24 does not impose a load on the rotation of the shaft 24, a material having a high slidability is used for the vibration regulating member 12, and a friction resistance The occurrence is suppressed. Examples of the material having high slidability include a resin such as a polyacetal resin in which a lubricant, a fluororesin, molybdenum dioxide, silicon oil, or the like is added to improve the lubricity of the resin surface. Since the shaft 24 is pressed by the vibration regulating member 12 made of such a material, the vibration is effectively suppressed, and at the same time, the rotation thereof is not hindered.

Although the cassette frame 23 is made of resin in this embodiment, it is made of a material that is not easily distorted (for example, metal).
Even when the above is used for the cassette frame, the configuration in which the vibration regulating member 12 is brought into contact with the shaft 24 is not ineffective. That is, when the cassette frame is made of metal, the chatter noise is unlikely to occur, but by additionally contacting the vibration regulating member 12 with the shaft 24 from above, the chatter noise is generated more reliably. To be avoided. Specifically, even when there is only one sheet on the flapper 21, it is possible to prevent even the chattering noise generated when the sheet is taken in. As a result, it is possible to provide a paper feeding device that is extremely quiet.

[0021]

Since the present invention regulates the vibration of the shaft with the above-mentioned structure, the chatter noise caused by the vibration of the shaft is effectively suppressed with a simple structure, and the quietness during operation is suppressed. It is possible to provide a paper feeding device having good quality.

[Brief description of drawings]

FIG. 1 is a perspective view of a facsimile device.

FIG. 2 is a side sectional view of a sheet feeding device.

FIG. 3 is an enlarged plan view showing a mounting portion of a vibration regulation member.

FIG. 4 is an enlarged side view of the same.

FIG. 5 is an enlarged rear view of the same.

FIG. 6 is a perspective view of a vibration regulation member.

[Explanation of symbols]

1 Facsimile machine 2 Paper feeder 12 Vibration regulation member 20 paper cassettes 21 flapper 22 Separated nail 23 cassette frames 24 shaft 25 pickup roller

Claims (3)

[Claims] 1. A paper feed cassette comprising a bottom plate on which recording paper can be placed, a spring for pushing up one end of the bottom plate, and a pickup roller provided on the free end side of the bottom plate, and the paper feed cassette. In a paper feeding device having a mountable cassette frame, a shaft supporting the pickup roller is supported on the cassette frame, and a restricting member for restricting upward movement of the shaft is provided. apparatus. 2. The sheet feeding device according to claim 1, wherein the regulating member abuts on a central portion of the shaft in the axial direction. 3. The sheet feeding device according to claim 1, wherein the regulating member is made of resin.