JPH0512187Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a paper feed cassette equipped with a paper separation device used in image forming apparatuses and the like.

[Prior art]

2. Description of the Related Art Conventionally, in order to take out and feed sheets one by one from a paper feed cassette in which a large number of sheets are stacked in an image forming apparatus or the like, separation claws are provided at both corners of the leading end of the cassette in the feeding direction.

The structure of a conventional separating claw will be explained with reference to the accompanying drawings. 7 to 9 show examples of conventional separating claws. Moreover, FIGS. 7 to 9 each show different structures of separation claws. FIG. 7 shows a structure in which a groove 2 is formed near the corner of the cassette 1, a separation claw 3 is inserted along this groove 2, and the separation claw 3 is attached to the cassette 1 with screws 4a and 4b. in this case,
The separation claw 3 is attached to the cassette 1 through elongated holes 5a and 5b provided on the side surface of the cassette 1 so as to be slidable vertically (in the same figure) with respect to the cassette 1.

FIG. 8 shows an example in which the separation claw 6 is integrally attached to the arm 9.
is provided at the tip of an arm 9 rotatably supported on the side wall of the paper feed cassette 8 by a rotation shaft 7. In the examples shown in FIGS. 7 and 8, a stack of sheets urged upward by a spring or the like (not shown) is held between the sheets, and a paper feed roller (not shown) is pressed against the topmost sheet of paper to feed the sheets one by one to the arrow A. Separate and feed in the direction or B direction.

However, the separation claw as described above has the following drawbacks.

(b) In the example shown in Figure 7, if the tolerance between the width of the groove 2 and the width of the separation claw 3 is too large, when the separation claw 3 is attached to the cassette, installation play will occur and the corner of the paper will be bent. If the paper is fed in a sticky state, it may cause image defects or jams.

(b) In the example shown in Fig. 8, paper powder and dust adhere to the bearing surface of the rotating shaft 7 of the arm 9, slowing down the movement.
A situation arises in which it is not possible to follow changes in the height of the paper, and it is not possible to press both corners of the paper accurately. As a result, if the separating claw 6 separates from the paper and cannot grip both corners, and the regulating force becomes small, double feeding of paper will occur, and the separating claw 6 will not follow the rise of the paper and will not be able to press the paper more tightly than necessary. However, as described above, the paper is fed with its corners bent, resulting in image defects and jams.

In order to solve the above-mentioned problems, a practical application
A separation claw shown in 018655 has been devised. The structure of this separating claw 10 is shown in FIG. 9 mentioned above.
To briefly explain the separation claw 10, the separation claw 10
consists of a supported surface 10a, a paper front end receiving surface 10b, and a paper top pressing surface 10c, which are arranged at right angles to each other. The supported surface 10a is a surface on which the supporting surface 11 shown in FIG.
0b is a surface on which the leading edge of the sheets stacked in the cassette 12 is located, and the paper top pressing surface 10c constitutes a surface that presses the top surface of the uppermost sheet of paper loaded in the cassette 12 to which it is fed. ing. Also,
The supported surface 10a is loosely fitted into a slide groove (not shown) provided in the support surface 11, and the separation claw 10 is supported so as to be slidable in the vertical direction. The sheets stacked in the cassette 12 using the separating claw 10 having such a structure are sequentially fed by a paper feeding roller (not shown) with the topmost sheet 13 curved as shown in the drawing. However, at this time, the sheets other than the uppermost one are reliably prevented from advancing by the convex portion 10e provided on the separating claw 10 and the leg portion 10f of the front end receiving surface 10b of the sheets, thereby preventing double feeding.

[Problems with conventional technology]

However, the above-mentioned application No. 61-018655
Even the separation claws shown in FIG.
is tilted relative to the cassette 12 and moves up and down.
FIG. 10 shows a state in which it is tilted to the right with respect to the cassette 12. In this way, the separation claw 10
If the paper is tilted and moved up and down, it becomes impossible to prevent double feeding of paper as described above. Furthermore, if the separation claws 10 are tilted to an extreme degree, the paper will get stuck between the separation claws 10, causing paper folds and paper jams. This also applies when the separation claw 10 is tilted in the front-rear direction (direction perpendicular to the plane of the paper).

[Purpose of invention]

In view of the above-mentioned conventional drawbacks, the present invention provides a paper feed cassette equipped with a paper separation device that smoothly feeds the paper stacked in the cassette and does not cause double feeding, paper folding, or paper jams. The purpose is to

[Summary of the invention] In order to achieve the above-mentioned object, the present invention provides a casing that has at least a bottom plate, a front wall and a side wall erected on the bottom plate, and stores paper therein; a push-up member that comes into contact with the lowest surface of the paper and pushes up the loaded paper toward the leading end in the paper feeding direction; a sliding groove formed on the leading end in the paper feeding direction of the side wall along the paper stacking direction; and the sliding groove. a supported surface attached to the groove; a paper leading edge receiving surface that is continuous and substantially perpendicular to the supported surface and abuts the leading edge of the stacked paper in the paper feeding direction; and a paper leading edge receiving surface that is continuous from the top of the paper leading edge receiving surface to the rear end side. and a paper upper surface pressing surface that is substantially orthogonal and abuts the top surface of the stacked paper, and a separating claw that is slidably disposed in the sliding groove. In the paper feeding cassette in which a leading end corner of the paper formed of a leading edge and a side edge is held between the separating claw and the pushing up member, the separating claw is movable in the paper stacking direction, the paper feeding direction, and the paper width direction. the supported surface is loosely fitted into the sliding groove, and a fixing part that is fitted into the sliding groove and fixedly held in the sliding groove engages with the supported surface of the separating claw; a first pressing portion that urges the separation claw downward;
a single elastic pressing member having second and third pressing parts that urge the separating claw in a direction opposite to the paper feeding direction and toward the center in the width direction; The separating claw is biased and movably supported within the sliding groove so that the paper upper pressing surface and the paper leading edge receiving surface are always brought into contact with the stacked paper.

[Example of idea]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view showing a part of a cassette and paper conveyance system having a separation device according to the present invention. In the figure, a large number of sheets T stacked in a cassette 15 are moved by a compression spring 17 interposed between a bottom plate 15a and a push-up plate 16, which constitute a part of the cassette.
It is urged upward (in the direction of arrow C) by the separation claws 18 and 19 provided at the tip of the paper feed cassette 15 in the paper transport direction, and the rise above a predetermined value is regulated by the separation claws 18 and 19, which will be described later. support member 26
It is supported by On the other hand, the half-moon-shaped paper feed roller 20 having the cutout portion 20a has the cutout portion 20a.
0a is stopped facing the top of the paper T. Then, it rotates in the direction of arrow D around the shaft 20b in response to an external feeding signal, and conveys the leading edge of the paper T to the position of the standby rolls 21a and 21b in one rotation. The paper T conveyed to the standby rolls 21a and 21b is further conveyed in synchronization with the image on the photoreceptor drum (not shown), and the toner image is transferred thereto.

FIG. 3 is a plan view of the main part of the tip of the cassette 15 in the paper conveyance direction (indicated by the arrow). The paper feed cassette 15 has a side wall 2 that forms part of the housing.
2. Support member 26 and paper feed cassette 15 (not shown)
A slide groove 2 in which the above-mentioned separating claws 18 and 19 for separating the sheets of paper T stored therein are slidably mounted in the vertical direction (in the direction perpendicular to the plane of the paper in FIG. 3).
It is composed of 3a, 23b, etc.

FIG. 1 is a perspective view showing the separation claw 18, which is one of the above-mentioned separation claws 18 and 19, and the support member 26. In the figure, the separating claw 18 includes a supported surface 18a and a paper front end receiving surface 1 disposed at right angles to each other.
8b, and a paper upper pressing surface 18c. Then, the supported surface 18a is connected to the slide groove 2.
3a (see FIG. 3), the separation claw 18 is supported so as to be slidable in the vertical direction. The paper front end receiving surface 18b is similar to the supporting surface 18a.
A concave portion 18d is provided at the center of the upper end, and a protrusion 18d is provided near the center of the paper T.
e is provided. Paper top pressing surface 18c
is formed to extend perpendicularly to the supported surface 18a side with respect to the paper front end receiving surface 18b, and presses the top surface of the front end corner of the paper T and holds the paper T with the aforementioned push-up plate 16. . In addition, the supported surface 18
Protrusions 25a and 25b are provided on a. On the other hand, the support member 26 is made of a plate-shaped elastic material,
an upper surface portion 26a, an end portion 26b bent at a right angle,
It has a curved portion 26c. And the end portion 26
The separation claw 18 and the support member 26 are installed in the slide groove 23a with the separation claw 18 and the support member 26 being fitted from above into the gap between the protrusions 25a and 26b of the supported surface 18a. In this case, the upper surface 2 of the support member 26
The width of the slide groove 6a is approximately the same as the width of the slide groove 23a, and when it is installed in the cassette 15 as shown in FIGS. 4 and 5, the upper surface portion 26a is fixedly held above the slide groove 23a. be done. and,
The curved portion 26c of the support member 26 presses the upper surface 18f of the supported surface 18a, and the end portion 26b presses against the projection 2.
5a and 25b, the separating claw 18 is pressed in the directions indicated by arrows X and Y. Next, when the attached state of the support member 26 and the separating claw 18 is visually observed from the direction of arrow E, the state shown in FIG. 4a is obtained.

In addition, the cassette 15 has a separation claw 18 and a support member 2.
Figure b is a plan view (with some cutouts) of the main part with 6 attached. When the support member 26 is taken into the cassette 15, as shown in FIG.
The upper surface part 26a and the end part 26d of the curved part 26c
(see a in the same figure) come into contact and press and support the separation claw 18. Further, the front side plate 23 of the cassette 15 is provided with protrusions 23c and 23d on the inner side, and is configured to abut against the paper front end receiving surface 18b of the separating claw 18. Therefore, the separation claw 18 is always biased and supported in a fixed position by the support member 26.

Although the separation claw 18 and the support member 26 have been described above, the separation claw 19 and the other support member have exactly the same configuration as the separation claw 18 and the support member 26, except that they are symmetrical.

Next, the operation of the separation apparatus of this embodiment will be explained with reference to FIGS. 5a and 5b.

FIG. 5a is a partially enlarged front view showing a state in which a large number of sheets T are stacked in the paper feed cassette 15 (the front plate 23 is partially cut away). In the same figure,
The paper T is pressed from below by the push-up plate 16 which is urged upward by the compression spring 17 mentioned above, and is restricted from rising above a certain level by the separation claws 18 and separation claws 19 (not shown).

Next, when the paper feeding operation starts, the paper feeding roller 2
Due to the rotation of 0, the peripheral surface comes into contact with the paper T and the paper T is pushed down, and the separation claw 1
8 and 19 descend along the slide grooves 23a and 23b. In this case, the aforementioned protrusions 25a and 25b descend along the end portion 26b. Then, the top paper T ₁ among the stacked papers T is placed at the paper feed roller 2.
0, but since both corners are held down by the separating claws 18 and 19,
As shown in the figure, only the central portion curves and bulges, and is separated from the paper T below. In this case, separation claw 1
Since the upper surface 18f of 8 and 19 is constantly pushed downward by the curved portion 26c of the support member 26 and is supported by the end portion 26b, the separating claw 18 or 19 and the slide groove 23a or 23b Even if there is any play in the installation, this play will be eliminated by the above-mentioned force.

Therefore, according to the paper feed cassette of this embodiment, the separating claws 18 and 19 always follow the paper T and move smoothly, maintaining an appropriate posture, so that the paper can be reliably fed one by one. Double feeding will not occur.

FIG. 6 is a block diagram of a paper feed cassette separation device according to another embodiment of the present invention. In the same figure, the separation claw 30 is composed of a supported surface 30a, a paper front edge receiving surface 30b, and a paper upper surface pressing surface 30c, as in FIG. . The support member 32 is also different in shape from the above-described support member 26 in that an end portion 32a bent at a right angle is located on the inside, and another curved portion 32c is provided in addition to the curved portion 32b. This end portion 32a is connected to the protrusions 31a, 31
By being fitted into the gap b, the end portion 32a presses the separation claw 30 in the X direction as described above, and the curved portion 32b presses the upper surface 30f of the separation claw 30 downward. On the other hand, the other curved portion 32c and end portion 32b are configured to restrict movement of the separation claw 30 in the Z direction. In this case as well, the width of the upper surface of the support member 32 is formed to be approximately the same as the width of the slide groove 23a, and the upper surface portion is formed to have the same width as the slide width 23a.
It is fixedly held in contact with the lower surface of the cassette side plate 22 above. Therefore, since the separation claw 30 is always subjected to a force that maintains the proper posture by the support member 32, even if there is an attachment play between the separation claw 30 and the slide groove, this play will be compensated for as described above. It is resolved by the power of.

[Effect of idea]

As explained in detail above, according to the present invention, by biasing the separation claw in a predetermined direction by the support member (plate spring), the separation claw is supported in an appropriate position and the looseness of the separation claw is eliminated. Therefore, double feeding of paper, folding of paper, and paper jam can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a separating device installed in the paper feed cassette of this embodiment, FIG. 2 is a cross-sectional view of the paper feed cassette of this embodiment, and FIG. 3 is a schematic diagram of the paper feed cassette of this embodiment. FIG. 4a is a side view of the separation device installed in the paper feed cassette of this embodiment, FIG. 4b is a plan view of the main part of the paper feed cassette of this embodiment, and FIGS.
b is an explanatory diagram of the operation of the separating device disposed in the paper feed cassette of this embodiment, FIG. 6 is a perspective view of another embodiment of the separating device disposed in the paper feed cassette of the present invention, and FIG. 7 , FIG. 8, FIG. 9, and FIG. 10 are block diagrams of a separation device installed in a conventional paper feed cassette. 15... Cassette, 18, 19, 30... Separation claw, 19a... Supported surface, 19b... Paper front receiving surface, 19c... Paper top pressing surface, 20... Paper feed roll, 25a, 25b, 31a ,31b...
Projections, 26, 32...Supporting members.

Claims (1)

[Claims for Utility Model Registration] Bottom plate 15a and front wall 2 erected on bottom plate 15a
3 and a side wall 22, and a housing 15 for stacking and storing sheets, and a push-up member disposed within the housing 15 for abutting against the lowermost surface of the loaded sheets T and pushing up the leading end side of the loaded sheets T in the sheet feeding direction. 16, and sliding grooves 23a and 23b formed on the front end side of the side wall 22 in the paper feeding direction along the paper stacking direction.
Supported surfaces 18a and 30a attached to the sliding grooves 23a and 23b, and a paper leading edge receiving surface that is continuous and substantially orthogonal to the supported surfaces 18a and 30a and abuts the leading edge of the stacked paper T in the paper feeding direction. 18b, 30b, and the uppermost surface _T1 of the stacked paper T, which is continuous and substantially orthogonal from the top to the rear end side of the paper leading edge receiving surfaces 18b, 30b.
and separating claws 18, 19, 30 which are slidably disposed in the sliding grooves 23a, 23b, and have paper upper pressing surfaces 18c, 30c that come into contact with the stacked paper T when feeding the paper. In the paper feed cassette 15, in which the leading edge corner of the paper, which is formed by the leading edge and the side edge of , the supported surfaces 18a and 30a are arranged in the sliding groove 23 in order to be movable in the paper feeding direction and the paper width direction.
a, 23b, and is fitted into the sliding grooves 23a, 23b and fixedly held in the sliding grooves 23a, 23b.
a, 32 engages with the supported surfaces 18a, 30a of the separating claws 18, 19, 30, and the separating claws 18,
1st pressing part 26 that urges 19, 30 downward
c, 32b, second and third pressing parts 26b, 32a, 26 that urge the separating claws 18, 19, 30 in the direction opposite to the paper feeding direction and toward the center in the width direction;
a single elastic pressing member 26 having b, 32c;
32, the elastic pressing members 26, 32 are provided with the separating claws 18,
19, 30, the paper upper pressing surface 18c, 30c
and the paper leading edge receiving surfaces 18b, 30b are always in contact with the stacked paper T, the separating claw 18,
19, 30 and the sliding grooves 23a, 23b.
A paper feed cassette 15 is characterized in that it is movably supported within the paper feed cassette 15.