JP3338749B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention employs a corner claw separation system for separating sheets stacked in a sheet cassette one by one and feeding them in a device such as a facsimile machine, a copying machine, a printer or the like. It relates to a paper feeding device.

[0002]

2. Description of the Related Art Conventionally, this type of sheet feeding apparatus has a separating mechanism for separating and feeding stacked sheets one by one. As a separation method, there are a friction separation method using a friction pad or the like, a corner claw separation method, and other methods. For a fixed size such as A4 and B5, a simple corner claw separation method is most frequently used.

A conventional example of a paper feeder using such a corner claw separation method will be described with reference to FIG. First, paper 1
The paper feed cassette 2 is provided for accommodating in a stacked state. The paper feed cassette 2 is fixed to both the left and right sides of the cassette case 3 formed of a synthetic resin or the like, and regulates the width direction of the paper 1 to a standard size (for example, A4, B5, etc.). And a sheet guide 4 made of sheet metal. A pair of separation claws 5 formed of a sheet metal or the like, which are located at the leading end side in the paper feeding direction, are attached to these paper guides 4 so as to be vertically rotatable by a support shaft 6. These separation claws 5 are used for the stacked paper 1
The claw portions 5a are formed so as to be bent at both side corners of the front end portion in the sheet feeding direction. In addition, the cassette case 3
A bottom plate 7 on which the sheets 1 are stacked is provided on a bottom surface of the inside. The bottom plate 7 is made of a sheet metal formed in an appropriate shape and in the shape of a flat plate. The bottom plate 7 is set at the rear side in the cassette case 3, and the tip side is rotatable in the vertical direction with the fulcrum 8 as a fulcrum. A back plate 9 for regulating the position of the rear end of the stacked sheets 1 is detachably attached to the rear end of the cassette case 3. A rib 10 for regulating the position of the leading end of the sheet 1 is formed at the leading end in the cassette case 3.

[0004] Such a paper feed cassette 2 is removably mounted substantially horizontally on a predetermined paper feed section provided with a pickup roller 11. This pickup roller 11
Is a rubber roller formed, for example, in a semicircular shape. The rubber roller takes a position slightly above the claw portion 5a of the separation claw 5 and at the top of the uppermost sheet, and is driven by one rotation during paper feeding. The paper feed cassette 2 is mounted on the paper feed section and the compression spring 1
The leading end side of the bottom plate 7 is pushed up by a biasing member such as 2 so that the uppermost sheet of the paper 1 on the bottom plate 7 is in a raised position where it can contact the pickup roller 11 regardless of the number of stacked sheets. Have been.

In such a configuration, when the pickup roller 11 makes one rotation based on the sheet feeding command, a conveying force in the sheet feeding direction acts on several sheets on the uppermost sheet side of the stacked sheets 1, The movement of these sheets 1 is regulated by the claw 5a of the separation claw 5, but finally, the displacement operation is such that only the topmost sheet gets over the claw 5a. The paper is fed in the paper feeding direction. In this way, only the top sheet is separated and fed.

Here, the back plate 9 is for regulating the position of the rear end of the paper 1. However, if the size is exactly the same, the ease of setting the paper 1 in the cassette case 3 is deteriorated. It is mounted at a position where a gap of about 1.5 to 2.5 mm is vacant with respect to one rear end. On the other hand, the compression spring 1
Since the inclination angle of the bottom plate 7 urged upward by 2 becomes steeper as the number of sheets 1 decreases, the sheets 1 stacked on the bottom plate 7 also hit the rear side, that is, the back plate 9. Will be lowered to the position. As a result, on the leading end side of the sheet 1, the claw portions 5 of the separation claw 5 at the left and right corners are formed.
a may occur. If the leading edge of the sheet 1 comes off from the claw portion 5a, a normal separation sheet feeding operation cannot be performed, and a double feed or the like occurs.

There are two ways to prevent such a problem. The first is a method in which the claw portion 5a of the separation claw 5 is formed to be large so that it does not come off from the claw portion 5a even when the paper 1 is lowered. Second, as shown in FIG. 5, a leaf spring 13 is attached to the front side of the back plate 9 to push up the rear end of the stacked sheets 1 forward in the sheet feeding direction without deteriorating the sheet setting property. This is a method for preventing the leading end side of the sheet 1 from coming off the claw 5a.

[0008]

However, according to the first method, the possibility of frequent non-feeds increases due to the large claw portion 5a. That is, in consideration of the separation function indicated by the claw portion 5a, the sheet 1 has an appropriate size in terms of the stiffness, ease of removal, and the like.

Further, according to the second method, the back plate 9 and the leaf spring 13 must be used, which increases the cost.

[0010]

According to the first aspect of the present invention, a pair of separation claws are provided at both side corners of the leading end in the sheet feeding direction in the sheet feeding cassette and supported to be vertically rotatable. A bottom plate rotatably disposed on the bottom surface in the paper feed cassette with the rear side in the paper feed direction as a fulcrum and on which sheets are stacked, and a front end in the paper feed direction of the bottom plate being biased upward. And a biasing member for turning the corners of the sheet feeder.
Mounting boss that is removably mounted in the mounting hole formed in the part
Are formed so that these mounting bosses fit into the mounting holes
To be installed in the paper cassette.
The back of a molded product that regulates the position of the rear end of the paper
A plate is provided between the mounting boss and the back plate.
A spring portion which gave a spring property that left and right by positioning the point push toward the rear end of the sheets stacked on the bottom plate in the paper feeding direction forward of and integrally formed.

Accordingly, since the spring portion is integrally formed on the back plate itself and has the function of pushing up the rear end of the paper toward the front in the paper feeding direction, the separation paper feeding function by the corner claw separation system can be realized at low cost. It can be exhibited regardless of the number of sheets.

In this case, since the lower end of the spring portion of the back plate is inserted into the bottom surface of the paper feed cassette, the last sheet may be caught by the lower end of the spring portion. Paper can be fed without fail.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The overall configuration of the sheet feeding device including the sheet feeding cassette 2 is the same as that of the conventional example shown in FIG. 4, and the same portions are denoted by the same reference numerals.

The present embodiment is characterized by a back plate structure, in which a back plate 14 as shown in FIG. 2 is provided instead of the back plate 9 with the leaf spring 13 as shown in FIG. . The back plate 14 is a molded product mainly including a plate body 14a which is detachably provided at a predetermined position at a rear end portion in the sheet feeding direction in the cassette case 3. At three lower end portions of the plate body 14a, mounting bosses 14b are formed so as to be detachably mounted in mounting holes 15 formed in the bottom surface 3a of the cassette case 3. Here, as the mounting hole 15, FIG.
As shown in FIG. 5, an attachment hole 15a for attaching the plate body 14a to, for example, a rear end position for A4 size,
Mounting hole 15 for mounting at the rear end position for B5 size
and b are formed to move back and forth in the paper feeding direction. The positions of these mounting holes 15a and 15b are set at positions where a slight gap is formed between the plate body 14a and the rear end of the stacked sheets 1 with the back plate 14 mounted. . Further, in the back plate 14, the left and right two portions are made thinner than the plate body 14a, and a vertical cut 1 from the lower end side.
By inserting 4c, a spring portion 14d having spring properties with the upper end portion as a fulcrum is integrally formed. The spring portion 14d is slightly obliquely bent so as to project slightly forward from the front surface of the plate body 14a. Thereby, the resiliency of the spring portion 14d is set so as to act in a direction substantially perpendicular to the rear end of the sheets 1 stacked on the bottom plate 7, that is, in a direction of pushing up the sheet 1 forward in the sheet feeding direction. . The lower end of the spring portion 14d is
It is formed longer so as to take a position lower than the lower end of a. Thereby, the lower end of the spring portion 14d is set to be at a position lower than the surface of the bottom portion 3a of the cassette case 3 (that is, to enter into the bottom surface) when the back plate 14 is attached. At this time, the spring 1
A groove 3b is formed in the bottom surface 3a corresponding to the spring portion 14d along the paper feeding direction so as not to hinder the spring property of 4d.

In such a configuration, when the pickup roller 11 makes one rotation based on the sheet feeding command, a conveying force in the sheet feeding direction acts on several sheets on the uppermost sheet side of the stacked sheets 1, The movement of these sheets 1 is regulated by the claw 5a of the separation claw 5, but finally, the displacement operation is such that only the topmost sheet gets over the claw 5a. The paper is fed in the paper feeding direction. In this way, only the top sheet is separated and fed.

At this time, since the inclination angle of the bottom plate 7 urged upward by the compression spring 12 becomes steeper as the number of sheets 1 decreases, the sheets 1 stacked on the bottom plate 7 also Side, that is, to a position where the back plate 14 comes into contact with the surface of the plate body 14a. Here, a spring portion 14d is formed integrally with the back plate 14, and the rear end portion of the paper 1 stacked on the bottom plate 7 is directed forward in the sheet feeding direction by the spring property of the spring portion 14d. Since the sheet receives the force in the direction of pushing up, the sheet 1 does not fall to the rear end side even if the bottom plate 7 is inclined. Therefore, the leading end side of the sheet 1 does not come off from the claw portions 5a of the separation claws 5 at the left and right corners, and a normal separation sheet feeding operation can be performed. Such an operation is exerted up to the last sheet irrespective of the number of sheets 1 on the bottom plate 7. In particular, since the lower end of the spring part 14d enters a position lower than the surface of the bottom part 3a of the cassette case 3, the lower end of the spring part 14d and the bottom part 3a
Even if the number of sheets is small, the paper 1 can be smoothly fed without being caught on the lower end of the spring portion 14d even if the number of sheets is small.

[0017]

According to the first aspect of the present invention, there is provided a pair of separation claws disposed at both side corners of the leading end in the sheet feeding direction in the sheet feeding cassette and rotatably supported in the vertical direction; A bottom plate, which is rotatably disposed on the bottom surface in the paper feed cassette with the rear side in the paper feed direction as a fulcrum and on which sheets are stacked, and a biasing plate for urging the front end of the bottom plate in the paper feed direction upward. the sheet feeder corner pawl separation system and a energizing member, below which includes a central
At three end portions, a paper tray formed on the bottom of the paper feed cassette
The mounting boss that is detachably attached to the attached hole is formed to protrude.
By attaching these mounting bosses to the mounting holes,
A rear end portion of the sheet mounted in the sheet cassette;
Provide a mold product back plate that regulates the position of
Placed on the back plate at two places on the left and right between the mounting bosses
Spring portion which gave a spring property for pushing up toward the rear portion of the front SL sheets stacked on the bottom plate by location in the paper feeding direction forward
The than integrally formed, it can be exerted regardless of the number of sheets separated feeding function by corner pawl separation method in the inexpensive configuration.

According to the second aspect of the present invention, since the lower end of the spring portion of the back plate is inserted into the bottom surface of the paper feed cassette, the last sheet may be caught by the lower end of the spring portion. Paper can be fed without fail.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of the present invention.

FIG. 2 shows a back plate, (a) is a front view,
(B) is a bottom view and (c) is a longitudinal side view.

FIG. 3 is an exploded perspective view showing a structure near a mounting portion of a back plate.

FIG. 4 is a vertical sectional side view showing a conventional example.

FIG. 5 is a perspective view showing a back plate provided with a leaf spring.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 paper 2 paper feed cassette 3 a bottom surface 5 separation claw 7 bottom plate 8 fulcrum 12 biasing member 14 back plate 14 b mounting boss 14 d spring portion 15 mounting hole

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 1/04 326 H04N 1/00 108

Claims (2)

(57) [Claims] 1. A pair of separation claws provided at both side corners of a front end portion in a paper feeding direction in a paper feeding cassette and rotatably supported in a vertical direction, and supplied on a bottom surface in the paper feeding cassette. A corner claw separation system including a bottom plate that is rotatably arranged with the rear side in the paper direction as a fulcrum and on which paper is stacked, and a biasing member that pushes up and pushes the leading end of the bottom plate in the paper feeding direction upward. Paper feeder, the bottom of the paper feed cassette at the bottom three places including the center
The mounting boss that is removably mounted in the formed mounting hole
These mounting bosses are formed in the mounting holes
By being installed in the paper cassette,
Back press of the molded product that regulates the position of the trailing edge of the paper
And a left side between the mounting bosses on the back plate.
Sheet feeding apparatus, characterized in that integrally formed with a spring portion which gave a spring property for pushing up toward the rear end of the sheets stacked on the bottom plate is positioned in the right two positions in the paper feeding direction forward. 2. The sheet feeding device according to claim 1, wherein a lower end of the spring portion of the back plate is inserted into a bottom surface of the sheet feeding cassette.