JP3474069B2 - Paper feeder - Google Patents

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 separating and feeding sheets one by one in an image forming apparatus such as a copying machine, a printer, a facsimile, or the like.

[0002]

2. Description of the Related Art FIG. 5 shows an example of the structure of a conventional sheet feeding device.
As shown in the figure, in the conventional sheet feeding device, a sheet feeding cassette or a sheet feeding tray is used as an apparatus main body (not shown), a bottom plate 1 is arranged on the inner bottom portion of the apparatus main body, and a front end portion of the apparatus main body is separated. The claw 2 is provided.

A rear portion 1a of the bottom plate 1 is rotatably supported by the main body of the apparatus, and is constantly urged by a compression spring 3 so that the front portion is lifted upward. A large number of sheets are stacked and placed on the upper surface of the bottom plate 1. The upper edge of the front end of a sheet (hereinafter, referred to as upper surface sheet) A ′ located at the uppermost portion is hooked on the separating claw 2. As shown in FIG. 6, the separation claw 2 is lifted upward by the urging force of the compression spring 3 while the operation is stopped. However, the separation claw 2 has the projection 1
01 and a stopper hole 1 provided on the front surface of the apparatus main body 102
Since the upward movement range is regulated by the engagement with 03, the position O of the ascending end always has a constant height. As a result, the separating claw 2 regulates the height position of the upper surface paper A ′ at the position O when the operation is stopped.

A half-moon-shaped sheet feeding roller 4 is provided above the main body of the apparatus, and the sheet feeding roller 4 contacts the upper surface sheet A'and pushes the upper surface sheet A'forward. Since the front end portion of the pushed-out upper surface paper A ′ is hooked by the separation claw 2, it becomes arcuate between the paper feeding roller 4 and the separation claw 2, and a constant repulsive force is generated. Due to this repulsive force, the front end portion of the upper surface paper A'overhangs the separation claw 2 and is thereafter fed forward by the paper feeding roller 4.

The second sheet from the top located under the top sheet A'is also pushed forward by the frictional force between the top sheet A'and the bow between the sheet feeding roller 4 and the separating claw 2. It may become a state. However, when the magnitude of the repulsive force generated by this bending exceeds the frictional force with the upper surface paper A ', it returns to its original position in the apparatus main body again, and the second paper Double feeding is prevented.

[0006]

In the above-described conventional paper feeding apparatus, the half-moon-shaped paper feeding roller 4 presses the paper by its peripheral surface during the paper feeding operation and sinks the paper together with the bottom plate 1 by a certain amount. Then, the upper surface paper A'is sent out at a predetermined height position. As the sheet sinks, the separation claw 2 also descends to hold the upper sheet A ′ in a hooked state with respect to the front end portion thereof.

Here, when a large number of sheets are loaded in the main body of the apparatus, the sinking amount a becomes large as shown in FIG. On the other hand, when the amount of paper stored in the apparatus main body becomes small, as shown in FIG. 8, the upper surface paper immediately below the paper feeding roller 4 is in the initial state in which the operation is stopped due to the inclination of the bottom plate 1. Since the height position of A'is lower than that when the paper is full, the subsidence amount b due to the pressing of the paper feeding roller 4 is small.

The difference between the subsidence amounts a and b of the sheets becomes larger as the number of sheets accommodated in the apparatus main body increases. That is, the subsidence amount a becomes large when a large number of sheets are fully loaded in the apparatus body. When the subsidence amount a becomes large, the radius of the paper feeding roller 4 must also be larger than the subsidence amount.
Becomes larger.

In recent years, in image forming apparatuses such as copying machines, it has been desired to install a paper feeding device capable of accommodating a large amount of paper, for example, 500 sheets. There has been a problem in that the size of the entire forming apparatus has been increased. In addition, when a large amount of paper is largely settled by the pressure of the paper feeding roller 4, a large load is applied to the support shaft 4a of the paper feeding roller 4, and there is a risk of poor rotation and deterioration of durability of the support shaft 4a.

The present invention has been made in view of the above-mentioned circumstances, regardless of the number of sheets accommodated in the main body of the apparatus,
Reduces the amount of pressing and sinking of paper by the paper feeding roller,
An object of the present invention is to reduce the size of the paper feeding roller and reduce the load on the paper feeding roller.

[0011]

In order to achieve the above object, the present invention has the following constitution. The main body of the device, which can accommodate multiple sheets of paper in a stack, and the upper edge of the front end is the paper feed part. The bottom plate is rotatably provided inside the main body of the device with the rear part as a fulcrum. Biasing means for urging the side up The sheet feeding roller that can be moved up and down on the uppermost surface of the sheets accommodated in the main body of the apparatus. It is provided in the main body of the apparatus, swings independently of the bottom plate, and partially stoppers. Swing member with a part Separation claw that is provided on the swing member and locks the front end of the uppermost surface of the paper stored in the main body of the device. The stopper part of the swing member abuts to regulate the height position of the separation claw. In addition, the adjusting member that adjusts the height position of the separation claw by changing the position where the stopper portion of the swinging member abuts according to the rotating position of the bottom plate.

A large number of sheets are placed on the upper surface of the bottom plate provided in the main body of the apparatus. At this time, the front end of the uppermost surface of the sheet is locked by the separation claw. The front side of the bottom plate and the sheets placed on the bottom plate are lifted by the biasing means. on the other hand,
Since the front end of the uppermost surface of the sheet is hooked by the separating claw, the height of the upper surface of the sheet is regulated to a predetermined position against the biasing force of the biasing means. Here, the height position of the separation claw is regulated against the biasing member by the stopper of the swinging member contacting the adjusting member.

When there are many sheets of paper on the bottom plate, the bottom plate is in a sinking state to a low position. On the other hand, as the number of sheets of paper on the bottom plate decreases, the front end of the bottom plate is lifted. The adjusting member changes the contact position of the swing member with the stopper portion according to the rotation of the bottom plate. Along with this, the height position of the separation claw changes. As a result, the amount of pressing and sinking of the sheet by the sheet feeding roller can be adjusted.

That is, when there are many sheets of paper and the bottom plate is sunk to a low position, the height position of the separating claw is lowered, and the front side of the bottom plate is lifted due to the decrease of the paper,
The adjusting member is interlocked with the rotation of the bottom plate so that the height position of the separating claw is raised. Preferably, the height position of the separating claw is changed so that a portion of the upper surface of the sheet housed in the apparatus body, which is in contact with the sheet feeding roller, maintains a substantially constant height in a non-contact state of the sheet feeding roller. Let With this configuration, the amount of pressing and sinking of the bottom plate and the sheet by the sheet feeding roller becomes constant, and the amount of pressing and sinking can be reduced particularly when there are many sheets.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 are side views of a main part for explaining a sheet feeding device according to an embodiment of the present invention, FIG. 1 shows a state in which sheets are fully loaded, and FIG. 2 shows a state in which the number of accommodated sheets is small. ing. FIG. 3 is a partially cutaway plan view showing the outline of the device.

The sheet feeding device has a box-shaped sheet feeding tray having an open upper surface as shown in FIG. When the apparatus main body 11 is formed of a paper feed tray, it is attached to an image forming apparatus such as a copying machine, a printer or a facsimile in a pull-out manner.
When 1 is a paper feed cassette, it is detachably attached to the image forming apparatus. The apparatus main body 11 is provided with a side plate 12 according to the size of the paper to be stored, and the paper is stored inside the side plate 12. The apparatus main body 11 has a paper feed portion 11a for the paper at the upper edge of the front end, and the paper is fed from the paper feed portion 11a one by one to the right in the figure.

A bottom plate 13 is provided on the inner bottom of the apparatus body 11. A rear portion of the bottom plate 13 is rotatably attached to the apparatus main body 11 via a support shaft 14. This bottom plate 13
Is always biased in a direction in which the front side is lifted by a spring member 15 as a biasing means (see FIGS. 1 and 2).

A swinging member 16 is swingably attached to a front end portion of the side plate 12 via a support shaft 17, and a separating claw 18 is provided above the front end of the swinging member 16. The separation claw 18 is located in the paper feed section 11a of the apparatus body 11, and hooks the front end of the uppermost surface of the sheets stored in the apparatus body 11. The oscillating member 16 uses its own weight or a biasing member such as a spring,
It is urged clockwise in FIGS. 1 and 2. However, the urging force is much smaller than the urging force transmitted to the separation claw 18 via the bottom plate 13 and the paper. Therefore, the swinging member 16 is about to swing in the counterclockwise direction in FIGS. 1 and 2 due to the biasing force from the spring member 15 acting on the separation claw 18. On the back surface of the swing member 16, a stopper portion 16a is provided.
Are formed so as to project laterally.

The sheet accommodated in the main body 11 of the apparatus is delivered by the sheet delivery roller 19 as described later. The paper feeding roller 19 is rotationally driven around a support shaft provided in a target device (hereinafter, referred to as an equipment target device) such as an image forming apparatus equipped with a paper feeding device. Since the paper feeding roller 19 has a half-moon shape, it is generally called a half-moon roller. When the sheet feeding roller 19 rotates, the peripheral surface thereof comes into contact with the uppermost sheet (upper sheet) A in the apparatus body 11, and the upper sheet A is delivered from the sheet feeding section 11a. The position where the sheet feeding roller 19 contacts the upper surface sheet A can be set arbitrarily, but it is generally preferable to contact the upper surface sheet A at a position slightly rearward of the sheet feeding portion 11a.

An adjusting member 20 is swingably attached to the front end of the side plate 12 independently of the swing member 16 via a support shaft 21. Here, the adjusting member 20 is located outside the side plate 12, so that when the paper is stored inside the side plate 12, the adjusting member 20 is prevented from obstructing and the workability is improved.

The adjusting member 20 is partially provided with a bottom plate contact portion 20.
The cam portion 20b is formed in the other part. FIG. 4 is an enlarged side view showing a mounting portion of the adjusting member 20 and the swing member 16 described above. As shown in FIG. 4, the bottom plate contact portion 20a of the adjusting member 20 is biased by its own weight or a biasing means such as a spring, and is constantly in contact with the upper surface of the bottom plate 13. In the adjusting member 20 having the shape shown in the same figure, the bottom plate contact portion 20a extends from the tip end x protruding in a claw shape to the intermediate point y of the continuous curved surface, and any portion of this region is the bottom plate 13. Contact the upper surface of. That is, when the bottom plate 13 is rotated from the low position shown by the solid line in the figure to the high position shown by the imaginary line, the end portion 1 of the bottom plate is halfway.
The bottom plate contact portion (curved surface portion) 20a contacts 3a. As described above, the adjusting member 20 that contacts the bottom plate 13 is
It rotates around the support shaft 21 in conjunction with the rotation of.

On the other hand, the cam portion 20b of the adjusting member 20 abuts on the stopper portion 16a of the swinging member 16, and the swinging member 1
The rocking of 6 in the counterclockwise direction in the figure is restricted. Cam part 20
The shape of b corresponds to the rotation position of the bottom plate 13 and the swing member 1
It is necessary to properly design 6 so that it can be held at a desired swing position. In this embodiment, as the bottom plate 13 rotates from the low position shown by the solid line in FIG. 4 to the high position shown by the imaginary line, the swinging member 16 gradually swings counterclockwise and the separating claw 18 moves. The cam portion 20b is formed so as to raise. More specifically, even if the bottom plate 13 is rotated, the portion (c in FIG. 4) on the uppermost surface of the sheet which is in contact with the sheet feeding roller 19 has a substantially constant height in the non-contact state of the sheet feeding roller 19. The cam portion 20b is formed so as to maintain it.

Next, the operation of the above-mentioned paper feeding device will be described. First, a large number of sheets are stored in the apparatus main body 11 so as to be stacked on the bottom plate 13. At this time, the separation claw 18 is hooked on the upper edge of the front end portion of the accommodated upper surface paper. The bottom plate 13 on which a large number of sheets are placed is shown in FIG. 1 (solid line in FIG. 4).
It is placed in the low position as shown in. In the adjusting member 20, the bottom plate contact portion 20a is in contact with the bottom plate 13, and the cam portion 20b is in contact with the stopper portion 16a of the swing member 16. The adjusting member 20 regulates the swinging position of the swinging member 16, and the separation claw 18 maintains a predetermined height position. When the paper feeding roller 19 is rotationally driven from this state and the paper feeding operation is started, the peripheral surface of the paper feeding roller 19 comes into contact with the upper surface paper A, sinks the paper downward, and pushes the upper surface paper A forward. Go.

Since the front end of the pushed-out upper surface paper A is hooked by the separating claw 18, it becomes arcuate between the paper feeding roller 19 and the separating claw 18, and a constant repulsive force is generated. Due to this repulsive force, the front end of the upper surface paper A is separated by the separation claw 18.
After that, the paper is fed forward by the paper feeding roller 19.

The second sheet from the top is also pushed forward by the frictional force between it and the upper sheet A, and becomes an arc between the sheet feeding roller 19 and the separating claw 18. However, when the magnitude of the repulsive force generated by this bending exceeds the frictional force between the upper sheet and the upper sheet A, the second sheet from the top slips and returns to the original state again, and thus double feeding is performed. To be prevented.

Each time the above-described sheet feeding operation of the upper sheet A is repeated, the bottom plate 13 is gradually rotated counterclockwise in FIG. 1 (FIG. 4). Then, with the rotation of the bottom plate 13,
The adjusting member 20 rotates counterclockwise in FIGS. 1 and 4, and the contact portion of the cam portion 20b with the stopper portion 16a (the swinging member 16) changes. As a result, the swinging position of the swinging member 16 changes in the counterclockwise direction, and the separation claw 18 gradually rises.

Now, in FIG. 4, a state in which a large number of sheets are placed on the bottom plate 13 (state of FIG. 1) is shown by a solid line, and a state where the sheets on the bottom plate 13 are slightly left (FIG. 4). 2) is shown in phantom in FIG. The dashed-dotted line d in FIG. 4 is a straight line extending vertically downward from the center of the paper feeding roller 19, and at the intersections c and c of this dashed-dotted line d and the upper surface paper in each state, the paper feeding roller 19 is changed to the upper surface paper. Contact. As is clear from FIG. 4, these intersections c, c
Is in the same position in each state, the amount of subsidence of the sheet and the bottom plate 13 due to the pressure contact of the sheet feeding roller 19 is always kept constant. Therefore, at the time of the paper feeding operation, the paper feeding roller 19 need only press and sink the upper surface paper A to a position slightly below the intersection point c irrespective of the stacked amount of paper. As a result, the load on the support shaft of the roller 19 is reduced and the radius of the roller can be reduced.

Assuming now that the separation claw 18 is fixed without being lifted, when the remaining paper on the bottom plate 13 is very small, the top paper is placed at the position indicated by the broken line A "in FIG. The intersection e between the upper surface paper at this position and the above-mentioned alternate long and short dash line d (that is, the portion where the sheet feeding roller 19 contacts the upper surface paper) is at a lower position than the above-described intersection c as shown in FIG. When a large number of sheets are placed on the bottom plate 13 (state shown by the solid line in FIG. 4), it is necessary to sink the upper surface sheet A further below the intersection point e to perform the sheet feeding operation. Will increase significantly.

The present invention is not limited to the above embodiment. For example, the adjusting member is not limited to the shape shown in FIG. 4 and the like, and may be appropriately designed so that the swinging member can be held at a desired swinging position corresponding to the rotating position of the bottom plate. In addition to the image forming apparatus, the present invention can be applied to various sheet paper processing apparatuses that need to stack and stack sheet-shaped paper sheets and send the sheets one by one.

[0030]

As described above, according to the paper feeding device of the present invention, the amount of pressing and sinking of the paper by the paper feeding roller is reduced and the paper feeding roller is irrespective of the number of sheets stored in the main body of the apparatus. Can be downsized and the load on the paper feeding roller can be reduced.

[Brief description of drawings]

FIG. 1 is a side view of essential parts showing a state in which sheets are fully loaded in order to explain a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is likewise a side view of the essential parts showing a state in which the number of accommodated sheets has decreased.

FIG. 3 is a partially cutaway plan view showing the outline of the paper feeding device according to the embodiment.

FIG. 4 is a side view showing, in an enlarged manner, a mounting portion of the adjusting member and the swinging member in FIGS. 1 and 2.

FIG. 5 is a side view schematically showing a conventional paper feeding device.

FIG. 6 is an enlarged side sectional view showing a stopper that restricts a rising end of a separation pawl in the same apparatus.

FIG. 7 is a side view showing a state in which a conventional paper feeding device is fully loaded with paper.

FIG. 8 is a side view showing a state where the number of sheets accommodated in the conventional sheet feeding device has decreased.

[Explanation of symbols]

11: Device main body 12: Side plate 13: Bottom plate 14: Support shaft 15: Spring member 16: Swing member 16a: Stopper 17: Spindle 18: Separation claw 19: Paper feeding roller 20: Adjusting member 20a: Bottom plate contact part 20b: Cam part 21: Support shaft A: Top surface paper

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 3/56 310 B65H 1/12 310 B65H 1/24 G03G 15/00 516

Claims (3)

(57) [Claims] 1. An apparatus body capable of accommodating a large number of sheets in a stack and having a front end upper edge serving as a sheet feeding section, and rotatably provided inside the apparatus body with a rear portion as a fulcrum. A bottom plate, an urging means for urging the front side of the bottom plate in a direction of lifting the bottom plate, a sheet feeding roller that can be brought into contact with and separated from the uppermost surface of the sheets housed in the apparatus body, and provided in the apparatus body, A swinging member that swings independently of the bottom plate and partially has a stopper portion, and a front end portion of the uppermost surface of a sheet that is provided on the swinging member and is housed in the apparatus body is locked. The separation claw and the stopper portion of the swinging member abut on each other to regulate the height position of the separation claw, and the position at which the stopper portion of the swinging member abuts is changed according to the rotating position of the bottom plate. An adjusting member for adjusting the height position of the separation claw by A paper feeding device characterized by comprising. 2. The sheet feeding device according to claim 1, wherein in the adjusting member, a portion of the upper surface of the sheet accommodated in the apparatus main body, which is in contact with the sheet feeding roller, is in a non-contact state of the sheet feeding roller. A sheet feeding device, wherein the height position of the separation claw is adjusted so as to maintain a substantially constant height. 3. The paper feeding device according to claim 1, wherein the adjusting member is provided outside a paper storage space in the main body of the device.