JPH11263448A - Sheet storage device and picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent change of a distance between a sheet head end and a corner part of a sheet separation means and dislocation of the separation means, etc., at the time when a sheet placing means is in a state full of sheets and at the lowest level and at the time when it is in a state with a few pieces of the sheets and at the top level in the case of feeding the sheets placed on the sheet placing means free to revolve while separating them by the separation means. SOLUTION: A sheet placing means 35 free to revolve around a shaft 35c with sheets placed on it, a sheet separation means 7 to separate the sheets and an energizing means 9 to energize front parts of the sheets toward the sheet separation means are provided. It is possible to maintain a distance L1 roughly constant and prevent transportation failure of the sheets due to dislocation from the separation means by moving a transfer means 36 in the longitudinal direction interlocked with revolution of the sheet placing means and regulating rear ends of the sheets by a rear end regulating means 34 supported on the transfer means by connection of a recessed part 35b and a protruded part 36a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet storage device capable of storing a plurality of sheets, and an image forming apparatus which mounts the sheet storage device and forms an image on a sheet fed.

[0002]

2. Description of the Related Art As shown in FIG. 13, sheets such as sheets stored in a sheet cassette 1 as a sheet storage device are:
Pickup roller 11 and separation claw 7 as separation means
And is fed to the transport unit 13 and the registration roller 17. Thereafter, the sheet is conveyed to the image forming unit at a timing by a registration roller.

In the image forming section, a photosensitive drum 14a as an image carrier is disposed, and an electrostatic latent image is formed on the photosensitive drum by an electrophotographic method using a laser beam modulated by image information from an optical unit. Is formed. The latent image is developed with toner by the developing means 14b to form a toner image. The toner image is transferred to a sheet by a transfer unit, and the transferred sheet is conveyed to a fixing unit 16, where the toner image is heated and fixed on the sheet. Thereafter, the sheet is discharged to the outside of the image forming apparatus main body by the sheet discharging means. What forms an image in this way is generally known.

A conventional example of a sheet cassette as a sheet storage device will be described below in detail with reference to FIGS. A cassette orchest, which is a box-shaped frame of the paper cassette 2, has a mounting member 5 (hereinafter, referred to as a middle plate) for loading sheets and a middle plate 5.
Means such as a coil spring for urging the sheet in the direction of the pickup roller 11 serving as a sheet feeding means, a side regulating member for regulating the width direction of the sheet, and a trailing end regulating member 4 for regulating the trailing edge of the sheet. It is fixed. The intermediate plate 5 is rotatably supported at a substantially central portion of the frame body in the sheet sending direction by a rotating hinge portion 5c, and is further provided with a sheet height regulating and separating action forward of the supporting portion 5c in the sheet sending direction. Is supported rotatably by a separation claw 7b. Also, cassette 2
Is provided with a side wall 2a for determining the position of the leading edge of the sheet, and a predetermined distance L1 can be maintained between the leading edge of the sheet, which is regulated by the side wall, and the corner 7a of the separation claw 7, when the sheet is set. .

[0005] As shown in FIG. 12, when the remaining amount of paper is reduced, the middle plate 5 rotates upward. As a result, the distance between the leading end of the sheet and the corner 7a of the separation claw 7 is changed from L1 to L2.
(L2> L1), and the distance is widened.

Therefore, the rotation fulcrum 7b of the separation claw 7, the rotation fulcrum 5c of the middle plate 5, or the length of the middle plate are optimized, and the L2
Is kept within a predetermined distance.

[0007]

However, in the above-mentioned conventional example, there is no problem in a cassette having a small paper stacking capacity (for example, about 250 plain papers), but when the capacity is large (for example, 500 sheets), the above-mentioned problem is solved. The distance of L2 is further increased and cannot be kept below a predetermined amount. Therefore, 1. 1. When the number of sheets is small, the sheet is detached from the separation claw, causing a paper feeding failure. Even if the paper does not come off from the separation claw, there is a risk that the leading end of the paper may be caught between the claws and cause a feeding failure.

In order to eliminate such a drawback, the middle plate may be changed from a rotary type to a type that moves up and down in parallel, or an operator may be notified of the remaining number of sheets. You can also take measures such as getting
The apparatus becomes large and complicated, and the operator has to work with it.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to reduce the change in the distance between the leading end of the sheet and the corner of the separation claw as much as possible. To provide an image forming apparatus for forming an image.

[0010]

In order to achieve the above-mentioned object, the present invention provides a sheet mounting means which can rotate a sheet on which the sheet is mounted, and a front portion of the sheet mounting means in a sheet feeding direction. A sheet separating unit that separates sheets, a biasing unit that biases a front portion of the sheet placed on the sheet placing unit toward the sheet separating unit, and a rotation of the sheet placing unit. It has a moving means which moves in the front-rear direction in conjunction with it, and a rear end regulating means which is supported by the moving means and regulates the rear end of the sheet.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS.
4, a first embodiment of the sheet storage device according to the present invention will be described. As an image forming apparatus according to the present invention for forming an image on a sheet fed from the sheet storage apparatus, for example, the same apparatus as that described in the above-mentioned conventional example is applied.

As shown in FIG. 1, an intermediate plate 35 serving as a sheet placing means is provided in a cassette orchestra of a cassette 32 serving as a sheet storage device. The rear portion of the middle plate 35 as viewed in the sheet feeding direction is rotatably supported by a frame of the cassette by a shaft 35c, and the front portion of the middle plate is urged upward by a biasing means such as a coil spring 9. . On both sides of the middle plate 35, a pair of side regulating means 3 for regulating the side of the sheet as a sheet is slidably disposed.

A moving means 36 which slides in conjunction with the middle plate 35 is provided at the rear of the middle plate 35, and a rear end regulating means 34 for regulating the rear end of the sheet is supported upright by the moving means 36. The plate-shaped moving member 36 is provided on the bottom plate of the cassette 32 so as to be movable in the front-rear direction, that is, in the direction of the arrow, and is connected to the middle plate 35 by connecting means.
The moving member 36 can be moved back and forth in accordance with the rotation of 5. The connecting means comprises, for example, a concave portion 35b and a convex portion 36a fitted to the concave portion 35b, one of which is provided on the moving member 36 and the other is provided on the middle plate 35. For this reason, as shown in FIG. 2, the member 36 and the rear end regulating plate 34 slide in the direction of the arrow (b) in conjunction with the rotation of the middle plate 5 in the direction of the arrow (a).

A rear end regulating member 34 for regulating the rear end of the sheet is provided upright on the slidable moving member 36. The rear end regulating member 34 is of a type that can be fitted to the moving member 36 (fixed), a type that can be slid with respect to the moving member 36 and can be set at a predetermined position (movable support), or a type that is integrated with both. In the present invention, any of these formats may be used. The movable support type is, for example, FIG.
(B), the rear end regulating member 34 is slidably supported on the moving member 36, and is held at a predetermined position by engaging the lever 50 urged by the spring 51 with the rack 52. Is done.

Next, the operation of this embodiment will be described with reference to FIGS.

FIG. 3 shows a state in which the cassette is full of sheets, and FIG. 4 shows a state in which the number of sheets is small.

As shown in FIG. 4, when the middle plate rotates in the direction of arrow (c) when the number of sheets is small, the rear end regulating plate 34 moves (cooperates) in the direction of arrow (d). At this time, the sheet 18 is pushed to the right (in the direction of the nail) by a predetermined amount in the figure,
The distance L2 between the leading end of the sheet regulated by 2a and the corner of the separation claw 7 is substantially equal to L1 when the sheet is fully loaded (L1 ≒ L).
2) It is constituted so that it may become.

Here, the concave portion 35b of the middle plate is connected to the rotation support 35c.
3 (in the state of FIG. 3), the sliding amount of the member 36 and the rear end regulating plate with respect to the predetermined rotation angle of the middle plate 35 can be maximized, and the amount of pressing the paper is directly below. Optimization is achieved by fine-tuning in the vicinity. Other configurations are substantially the same as those of the conventional embodiment.

As described above, according to the present embodiment, the distance between the leading end of the sheet and the corner of the separation claw is maintained even when the intermediate plate is rotated in accordance with the state where the number of sheets is changed from the full state to the few sheets state. Is maintained substantially constant, and the separation of the sheet by the separation claw can be performed satisfactorily.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS.

The present embodiment differs from the first embodiment in that a slope is provided on at least one of the side wall 42a as a sheet leading end positioning portion provided on the cassette and the rear end regulating member 43. . The other configuration is the same, and the description is omitted.

In the present embodiment, as shown in FIGS. 5 to 9, the inclined portion 43a of the rear end regulation 43 is higher than the height of, for example, approximately half the number of sheets set, and the inclined portion of the sheet leading end positioning portion of the cassette is It was provided below the height of about half of the number of sets. In the illustrated example, the surface of the inclined portion that comes into contact with the sheet is linear or straight when viewed in cross section, but may be curved in an arc shape.

The operation of this embodiment will be described with reference to FIGS.

FIG. 7 shows a state in which sheets are fully loaded, FIG. 8 shows about half, and FIG. 9 shows a small number of sheets.

As shown in FIG. 7, it can be seen that the leading end of the sheet on the lower surface of the sheet when the sheet is set is regulated by the sheet leading end positioning portion 18c, and the trailing end regulating plate is set accordingly. The leading end of the sheet from the uppermost surface is maintained at the distance L1 so as to be pushed to the separation claw side, and the sheet near the center is maintained at a predetermined amount by a predetermined amount so as to maintain the clearance with the sheet front end positioning portion (play by the predetermined amount). ).

FIG. 8 shows a state in which the paper is about half. At this time, the rear end regulating plate 43 is moved in the direction of the arrow in conjunction with the rotation of the middle plate 35 to absorb the clearance (play). Further, the sheet 18b is pushed in the direction of the separation claw 7, and the distance L3
Is maintained for a predetermined amount (L1 ≒ L
3).

FIG. 9 also shows that a small amount of paper 18a
Direction, and the distance L2 is maintained by a predetermined amount (L1 ≒ L2 ≒ L3).

As described above, when the rear end regulating plate is moved only in accordance with the rotation of the middle plate, in the full, medium, and small number of sheets, for example, when the number of sheets that can be set is further increased, the leading end of the sheet and the separation claw are not removed. May not be able to stabilize (maintain a predetermined amount of distance), but it is easy to optimize the above distance by tilting and finely adjusting the trailing edge regulating plate and the paper leading edge positioning part. Was completed.

Here, the inclined portion may be formed on one of the rear end regulating plate and the sheet leading end positioning portion. In addition, although the inclined portion and the upright portion are divided near half the height of the stackable number of sheets, they may be divided at other heights.

[0030]

As described above, according to the present invention,
In a sheet storage device having a sheet placement unit, and a separation unit that separates a sheet fed from the sheet placement unit, a movement unit that moves in the front-rear direction in conjunction with the rotation of the sheet placement unit; And the rear end regulating means for regulating the rear end of the sheet, so that even when storing a large amount of sheets, the front end of the sheet and the separating means can be connected regardless of the number of sheets that can be set on the sheet placing means. The distance can be kept below a predetermined amount. Thereby, the separation means of the sheet at the time of a small number of sheets can be prevented from slipping off and getting in
Stable separation and feeding became possible. Further, since the configuration is simple, the sheet storage device does not become large and complicated, and the operator does not particularly need to work for stable sheet feeding.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a sheet storage device according to the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the sheet storage device according to the present invention.

FIG. 3 is an explanatory view of a fully loaded state of the first embodiment of the sheet storage device according to the present invention.

FIG. 4 is an explanatory diagram illustrating a state of a small number of sheets in the sheet storage device according to the first embodiment of the present invention.

FIG. 5 is a perspective view of a sheet storage device according to a second embodiment of the present invention.

FIG. 6 is an operation explanatory diagram of the second embodiment of the present invention.

FIG. 7 is an explanatory view of a fully loaded state according to a second embodiment of the present invention.

FIG. 8 is an explanatory view of a middle mounting operation according to the second embodiment of the present invention.

FIG. 9 is an explanatory view of placing a small number of sheets according to the second embodiment of the present invention.

FIG. 10 is a perspective view showing a conventional sheet storage device.

FIG. 11 is an operation explanatory view showing a full load state of a conventional example.

FIG. 12 is an operation explanatory view showing a state in which a small number of sheets are placed in a conventional example.

FIG. 13 is a view showing a conventional image forming apparatus.

[Explanation of symbols]

 2, 32, 42 ... cassette 3 ... side regulating plate 7 ... separation claw 9 ... spring 11 ... feeding roller 34, 43 ... rear end regulating member 35 ... middle plate 35b ... concave portion 35c ... rotating support shaft 36 ... moving member 36a ... Convex part 50 ... Lever 51 ... Spring 52 ... Rack L1, L2 ... Distance between sheet tip and separation claw corner

Claims (9)

[Claims] 1. A sheet mounting means for mounting a sheet and rotatably mounted thereon, a sheet separating means disposed at a front portion of the sheet mounting means in a sheet feeding direction and separating the sheet, and a sheet mounting means. Urging means for urging the front portion of the sheet placed on the sheet separating means, sheet moving means moving in the front-rear direction in conjunction with rotation of the sheet placing means, and a sheet supported by the moving means And a rear end regulating means for regulating the rear end of the sheet. 2. A sheet storage device according to claim 1, wherein a connecting portion between said sheet placing means and said moving means is provided substantially immediately below a pivot point of said sheet placing means. 3. The sheet storage device according to claim 1, wherein the rear end regulating means is slidably supported on the moving means. 4. A sheet placing means for placing a sheet thereon and rotatable, a leading end positioning portion for positioning a leading end of the sheet placed on the sheet placing means, and a sheet feeding direction of the sheet placing means. A sheet separating unit disposed at a front portion for separating a sheet, an urging unit for urging a front portion of the sheet placed on the sheet placing unit toward the sheet separating unit, and a rotation of the sheet placing unit. Moving means that moves in the front-back direction in conjunction with movement,
And a rear end regulating unit supported by the moving unit to regulate the rear end of the sheet, wherein at least one of the positioning portion and the rear end regulating unit is formed with a straight plane or an arc-shaped inclined surface. Seat storage device. 5. The sheet storage device according to claim 4, wherein the inclined surface is formed above substantially the center of a height at which the rear end regulating means can place a sheet. 6. The sheet storage device according to claim 4, wherein the inclined surface is formed below substantially the center of the height at which the leading end positioning portion can place the sheet. 7. The sheet storage device according to claim 4, wherein a connecting portion between the sheet placing unit and the moving unit is provided substantially immediately below a pivot point of the sheet placing unit. 8. A sheet storage device according to claim 4, wherein said rear end regulating means is slidably supported on said moving means. 9. An image forming apparatus comprising: the sheet storage device according to claim 1; and image forming means for forming an image on a sheet fed from the sheet storage device.