JP3468610B2 - 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 and a facsimile.

[0002]

2. Description of the Related Art FIG. 6 shows an example of the structure of a conventional sheet feeding device.
As shown in the figure, in a conventional paper feeding device, a paper feeding cassette or a paper feeding tray is used as a paper accommodating main body (not shown), a bottom plate 11 is arranged on an inner bottom portion thereof, and a front end portion of the paper accommodating main body is provided. The separation claw 12 is provided on the upper edge.

A rear portion 11a of the bottom plate 11 is rotatably supported by the sheet accommodating main body, and is constantly urged by a spring member 13 so that the front portion is lifted upward. A large number of sheets of paper are stacked and placed on the upper surface of the bottom plate 11. The separating claw 12 hooks the upper edge of the front end portion of the sheet group, resists the biasing force of the spring member 13, and keeps the bottom plate 11 and the sheet group at a constant height position in the initial state while the operation is stopped. Regulated.

A half-moon-shaped sheet feeding roller 14 is provided above the sheet accommodating main body, and the sheet feeding roller 14 comes into contact with a sheet (hereinafter referred to as upper surface sheet) A'located at the top of the sheet group. , Push the upper surface paper A ′ forward. Since the front end portion of the pushed-out top surface paper A ′ is hooked on the separation claw 12, it becomes arcuate between the paper feed roller 14 and the separation claw 12, and a constant repulsive force is generated. Due to this repulsive force, the front end portion of the upper surface sheet A'overhangs the separation claw 12 and is thereafter fed forward by the sheet feeding roller 14.

The second sheet from the top, which is 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 14 and the separating claw 12. 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 the original position in the paper storage main body again,
Double feeding of the second sheet from above is prevented.

[0006]

The above-described conventional sheet feeding device has a half-moon-shaped sheet feeding roller 14 during the sheet feeding operation.
However, the peripheral surface thereof presses a group of sheets to sink them together with the bottom plate 11 by a certain amount, and sends out the upper sheet A ′ at a predetermined height position. In addition, as the paper group subsides,
The separation claw 12 also descends and holds the hooked state with respect to the front end portion of the upper surface paper A ′.

Here, when a large number of sheets are fully loaded in the sheet accommodating main body, the sinking amount a becomes large as shown in FIG. On the other hand, when the amount of paper stored in the paper storage body becomes small, as shown in FIG. 8, the paper feed roller 14 is in an initial state in which the operation is stopped due to the inclination of the bottom plate 11.
Since the height position of the upper surface paper A ′ immediately below is lower than that when the paper is full, the subsidence amount b due to the pressing of the paper feed roller 14 is small.

The difference between the subsidence amounts a and b of such a sheet group is
The larger the number of sheets accommodated in the sheet accommodating body, the larger the sheet. That is, the subsidence amount a becomes large when a large number of sheets are fully loaded in the sheet storage body. When the subsidence amount a becomes large in this way, the radius of the paper feed roller 14 must also be made larger than the subsidence amount, so that the paper feed roller 14 becomes large.

Recently, in an image forming apparatus such as a copying machine, it is desired to install a paper feeding device capable of accommodating a large amount of paper, for example, 500 sheets. In that case, the paper feeding roller 1
However, the size of the image forming apparatus as a whole has become a problem. In addition, when a large number of paper groups are largely settled by the pressing of the paper feed roller 14, a large load is applied to the support shaft 14a of the paper feed roller 14, resulting in poor rotation or the same support shaft 14.
There is a possibility that the durability performance of a is deteriorated.

The present invention has been made in view of the above-mentioned circumstances, and reduces the amount of pressing and sinking of a sheet group by the sheet feeding roller regardless of the number of sheets stored in the sheet storing body.
The purpose is to reduce the size of the paper feed roller and reduce the load on the paper feed roller.

[0011]

In order to achieve the above object, the present invention is capable of accommodating a large number of sheets in a stack, and a sheet accommodating main body having a front end upper edge serving as a sheet feeding section,
A bottom plate rotatably provided inside the sheet storage body with a rear part as a fulcrum, a biasing means for biasing the bottom plate in a direction in which the front side is raised, and a sheet feeding part of the sheet storage body, A separation claw that hooks the upper edge of the front end portion of the paper group stored in the paper storage body, and a sheet at the top of the paper group stored in the paper storage body that is driven to rotate about a support shaft ( A paper feeding device having a paper feed roller having a notch surface, which is formed in a half-moon shape whose peripheral surface comes into contact with a top surface paper at a contact point and pushes the paper forward, and is housed in the paper housing body. A paper height restricting member for restricting the height of the upper surface of the paper group is provided, and the position of the paper height restricting member in the height direction is the same as the cutout surface of the paper feed roller with the cutout surface horizontal. Set the position between the contact point and the paper height regulating member in the paper feeding direction.
Set the position behind the contact point in the paper feed direction, and
The paper group stored in the paper storage body is more than the specified thickness.
, The paper height regulating member causes
The height of the upper surface is regulated so that the paper group is thinner than the above specified thickness.
When the paper becomes full, use the separation claws alone to
The surface height is regulated so that the paper group is thicker than a specified thickness.
During the sheet feeding operation, the peripheral surface of the rotating sheet feeding roller comes into contact with the uppermost sheet regulated by the sheet height regulating member to sink the sheet downward and push it forward.

[0012]

A large number of sheets are stacked on the upper surface of the bottom plate provided inside the sheet body. Since the bottom plate is urged by the urging member in the direction in which the front side rises, the bottom plate tries to lift the front side of the stacked sheet group. On the other hand, the height of the upper surface of the sheet group is regulated by the sheet height regulating member. The height regulating position of the sheet group by the sheet height regulating member can be arbitrarily set within the range where the effect of the present invention can be obtained.

In particular, the paper height regulating member comes into contact with the top surface of the paper group at or near the front-rear position which is substantially the same as the contact point between the paper feed roller and the top paper, and regulates the height of the top surface of the paper group. By doing so, the upper surface height of the sheet group in the initial state can be kept constant without being affected by the inclination of the bottom plate, so that the effect of the present invention can be most remarkably exhibited. In this case, the height of the sheet group in the initial state is regulated by the sheet height regulating member from beginning to end, and the separation claw is
It only functions to separate the top sheet from the group of sheets.

In the structure in which the height of the sheet group is regulated by the separating claws as in the conventional example described above, the sheet feeding roller presses the sheet group particularly when the number of sheets to be accommodated is large, that is, when the sheet group is thick. The amount of subsidence increases. Therefore, the height of the upper surface of the sheet group may be regulated by the sheet height regulating member when the sheet group accommodated in the sheet accommodating main body has a predetermined thickness or more. In this case, when the paper group becomes thinner than the predetermined thickness, the upper surface height of the paper group may be regulated by the separating claw.

If the paper height regulating member is provided on the side plate of the paper accommodating main body, the same member can be supported by the side plate, and another supporting member is not required, so that the number of parts is reduced and the manufacturing cost is reduced. Is a low price.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are side views for explaining the sheet feeding device according to the first embodiment of the present invention.
Shows a state in which sheets are fully loaded, and FIG. 2 shows a state in which the number of accommodated sheets has decreased. Further, FIG. 3 is a plan view showing an outline of a sheet accommodating main body in the sheet feeding device.

The sheet feeding device forms the sheet accommodating main body 1 with a box-shaped sheet feeding tray having an open top surface as shown in FIG. 3 and a sheet feeding cassette. When the sheet accommodating main body 1 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, while when the main body 1 is a paper feeding cassette, the image forming apparatus is formed. It is detachably attached to. A side plate 2 is provided in the sheet storage main body 1 according to the size of the sheet to be stored, and the sheet is stored inside the side plate 2. The paper accommodating body 1 is
The upper edge of the front end portion is a paper feed unit 1a, and the paper is fed one by one from the paper feed unit 1a to the left in the figure.

A bottom plate 3 is provided on the inner bottom portion of the sheet accommodating main body 1. The bottom plate 3 is rotatable within the sheet storage main body 1 with the rear portion 3a as a fulcrum. The bottom plate 3 is constantly urged by a spring member 4 as an urging means in a direction in which the front side is lifted (see FIGS. 1 and 2). Separation claws 5 are provided at both ends of the sheet feeding unit 1a of the sheet accommodating main body 1. The separation claw 5 is rotatably supported at the base end by the side plate 2 and can move up and down within a certain range.
The separation claw 5 is always urged downward by its own weight or a biasing member such as a spring.

The sheet accommodated in the sheet accommodating main body 1 is sent out by a sheet feeding roller 6 as will be described later. The sheet feeding roller 6 is a target device (hereinafter referred to as an image forming apparatus) equipped with a sheet feeding device. , Which is a device to be equipped), is rotated about the support shaft 6a. Since the paper feed roller 6 has a half-moon shape, it is commonly called a half-moon roller. When the paper feed roller 6 rotates, the peripheral surface of the paper is the topmost paper (top paper) in the paper accommodating main body 1 attached to the equipment to be equipped.
The sheet A comes into contact with the sheet A and sends out the upper sheet A from the sheet feeding section 1a.
The position where the paper feed roller 6 contacts the top paper A can be set arbitrarily, but it is generally preferable to contact the top paper A at a position slightly behind the paper feed section 1a.

A paper height regulating claw (paper height regulating member) 7 is provided on the side plate 2 of the paper accommodating main body 1 so as to project inward. In this embodiment, with the paper accommodating main body 1 mounted on the equipment to be installed, the paper height is set at the front-rear position substantially the same as the contact point P between the upper surface paper A accommodated in the main body 1 and the paper feed roller 6. A regulating claw 7 is provided. The position in the height direction of the paper height regulating claw 7 is such that the cutout surface 6b of the paper feed roller 6 is in the horizontal state (the state shown in FIGS. 1 and 2) and the contact point P. It can be set at any position in between. In this embodiment, the position is set slightly above the contact point P (see FIG. 1 or 2).

Next, the operation of the above-described paper feeding device will be described. First, a large number of sheets are accommodated in the sheet accommodating body 1 so as to be stacked on the bottom plate 3. At this time, the separation claw 5 is hooked on the upper edge of the front end portion of the stored sheet group. Further, the sheet group is arranged below the sheet height regulating claw 7. This allows
The paper height regulating claw 7 presses the paper group from above regardless of the number of paper groups housed in the paper housing body 1. Therefore, the group of sheets in the sheet accommodating main body 1 are
The height is regulated to a position slightly above the height at which the sheet comes into contact with the upper surface sheet A. The separation claw 5 hooks the upper edge of the front end portion of the sheet group, but does not contribute to the height regulation of the sheet group.

The sheet containing main body 1 containing sheets is attached to the equipment to be equipped. When the operation of the paper feed roller 6 is stopped (initial state), the paper group in the paper storage body 1 is
The height is regulated by the paper height regulation claw 7 (see FIG. 1).
Of the solid line). When the sheet feeding roller 6 is rotationally driven from this state to start the sheet feeding operation, the peripheral surface of the sheet feeding roller 6 contacts the upper surface sheet A, and the sheet group is sunk downward (state of the phantom line in FIG. 1). ), And push the upper surface paper A forward.

Since the front end of the pushed-out upper surface paper A is hooked on the separation claw 5, it becomes arcuate between the paper feed roller 6 and the separation claw 5, and a constant repulsive force is generated. Due to this repulsive force, the front end of the upper surface sheet A crosses the separation claw 5, and thereafter, the sheet is fed forward by the sheet feeding roller 6. 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 becomes arched between the sheet feeding roller 6 and the separating claw 5. However, the magnitude of the repulsive force generated by this bending is
When the frictional force between the upper sheet A and the upper sheet A is exceeded, the sheet returns to its original position in the sheet accommodating body 1 again, so that the double feeding of the second sheet from the top is prevented.

In this embodiment, since the paper height regulating claw 7 presses the upper surface paper A at the front-rear position which is substantially the same as the contact point P between the upper surface paper A and the paper feed roller 6, FIG. As shown in, the number of sheets stored in the sheet storage main body 1 is reduced, and accordingly, the front side of the bottom plate 3 is lifted,
Even if the inclination of the sheet group stacked on the bottom plate 3 becomes large, the height of the upper sheet A in the initial state does not change. Therefore, in the sheet feeding operation, the subsidence amount h of the sheet group by the sheet feeding roller 6 becomes constant regardless of the number of sheets accommodated in the sheet accommodating main body 1 (see FIGS. 1 and 2).

In particular, even when the paper storage main body 1 is full of paper, the paper feed roller 6 can be downsized because it is not necessary to largely sink the paper group, and the paper feed roller 6 is also possible. The load acting on the support shaft 6a supporting the shaft is also small.

Next, a sheet feeding device according to the second embodiment of the present invention will be described. 4 and 5 are side views for explaining the sheet feeding device according to the second embodiment of the present invention.
Shows a state in which the sheets are fully loaded, and FIG. 5 shows a state in which the accommodated sheets have run out. The same parts as or the parts corresponding to those of the sheet feeding device of the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. As in the first embodiment described above, when the front-rear position of the paper height restricting claw 7 is set to a position substantially the same as the contact point P, the paper height restricting claw 7 causes the paper feeding roller 6 and its supporting shaft 6a. Need not to interfere with. In view of this, in the second embodiment, the paper height regulating claw 7'is arranged at a position rearward of the contact point P between the upper surface paper A and the paper feed roller 6 to expand the degree of freedom in design. .

With this structure, when the paper storage main body 1 shown in FIG. 3 is full of paper, as shown in FIG. 4, the paper height regulating claw 7'presses the top paper A. Then, the height of the paper group is regulated. Then, when the number of sheets in the sheet accommodating main body 1 is reduced as the sheet feeding operation is repeated and the group of sheets becomes thinner than a predetermined thickness, as shown in FIG. And bottom plate 3
The lifting of paper is regulated and the paper group is held at a constant height.

Even if the separation claw 5 entrusts the height regulation of the paper group,
If the thickness of the sheet group housed in the sheet accommodating main body 1 is thin, the amount of subsidence of the sheet group due to the pressing of the sheet feeding roller 6 is small, and therefore the sheet feeding roller 6 is downsized and the support shaft 6a is provided. It is possible to reduce the load on the. The thickness of the sheet group when the regulation of the sheet height is entrusted to the separating claw 5 is preferably as thin as possible. That is, the thickness of the sheet group when the regulation of the sheet height is entrusted to the separation claw 5 can be performed by adjusting the position of the sheet height regulation claw 7'in the front-rear direction, and the degree of freedom in design is not limited. It is preferable to bring the contact point P as close as possible to the front-rear direction position within the range.

The present invention is not limited to the above embodiment. If the paper height regulating members 7 and 7'are installed on the side plate 2 as in the above embodiment, the number of supporting parts is reduced and the manufacturing cost is reduced. It can also be provided independently of the side plate. Further, in the first embodiment, even if the paper height regulating claw 7 is brought into contact with the upper surface paper A at a position in the vicinity of the contact point P between the paper feed roller 6 and the upper surface paper A in the front-rear direction, the effect will be obtained. Little impact. The present invention can be applied not only to the image forming apparatus but also to various sheet paper processing apparatuses in which sheet-like sheets are stacked and stocked and fed one by one.

[0030]

As described above, according to the paper feeding apparatus of the present invention, the amount of pressing and sinking of the paper group by the paper feeding roller is reduced regardless of the number of papers stored in the paper storage main body. The paper roller can be downsized and the load on the paper feeding roller can be reduced.

[Brief description of drawings]

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

FIG. 2 is likewise a side view showing a state where the number of stored sheets has decreased.

FIG. 3 is a plan view showing an outline of a sheet storage main body in the sheet feeding device according to the embodiment.

FIG. 4 is a side view showing a state in which sheets are fully loaded in order to explain the sheet feeding device according to the second example of the present invention.

FIG. 5 is likewise a side view showing a state in which the number of stored sheets has decreased.

FIG. 6 is a side view schematically showing a conventional paper feeding device.

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]

1: Paper storage body 2: Side plate 3: Bottom plate 4: Spring member 5: Separation claw 6: Paper feed roller 7, 7 ': Paper height control claw

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 1/18 310 B65H 1/12 310 B65H 3/56 310 B41J 13/00 B41J 13/02

Claims (2)

(57) [Claims] 1. A plurality of sheets can be stacked and accommodated.
, The paper storage main body whose upper edge is the paper feed section,
Inside the paper storage body, the rear part can rotate freely
The bottom plate provided and this bottom plate in the direction in which the front side rises
Biasing means for urging and provided in the paper feed section of the paper storage body
On the front edge of the paper group stored in the paper storage body
The separation claw that locks the edge and the rotation around the support shaft
At the top of the paper group stored in the paper storage body
The peripheral surface of the paper contacts at the contact point and pushes the paper forward.
A sheet feeding roller formed in a moon shape and having a notch surface
Paper feeder, The height of the upper surface of the paper group stored in the paper storage body is regulated.
A paper height regulating member for controlling the height of the paper is provided.
Set the position in the height direction so that the cutout surface of the paper feed roller is horizontal.
The position between the notch surface and the contact point in the state ofThe position of the paper height regulating member in the paper feeding direction is set from the contact point.
Is also set to the rear position in the paper feeding direction, and
If the loaded paper group is thicker than the specified thickness,
The top height of the paper group is regulated by the paper height regulation member
However, when the paper group becomes thinner than the specified thickness
Regulates the height of the top surface of the paper group only by the separation claw
And then When the paper group is thicker than the specified thickness Rotate during paper feeding operation
The peripheral surface of the paper feeding roller is
Touch the regulated top sheet and move it downwards.
It is characterized in that it is made to sink and pushed forward
Paper feeder. 2. The sheet feeding device according to claim 1, wherein the sheet height regulating member is installed on a side plate of the sheet accommodating main body.