JP3090169B2 - Paper cassette - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed cassette provided in an image forming apparatus such as a copying machine, a printer, a facsimile and the like.

[0002]

2. Description of the Related Art FIG. 6 shows a configuration of a conventional paper feed cassette of a nail separation type provided in an image forming apparatus such as a copying machine, a printer, a facsimile or the like.

[0003] This paper feed cassette includes a middle plate 2 for stacking sheet materials S in a cassette body 1 and a middle plate 2.
Left and right side regulating plates (sheet material regulating plates) 3A, 3B for regulating the position in the width direction of the sheet material S stacked thereon.
A rear end regulating plate (sheet material regulating plate) 5 for regulating the rear end position of the sheet material S stacked on the middle plate 2;
Left and right push-up springs (coil springs) 7A and 7B for pushing the sheet material S stacked on the intermediate plate 2 against the sheet feeding roller 6, and the sheet material S fed to the sheet feeding roller 6. And left and right separation claws 9A and 9B for separating only the uppermost sheet into one sheet.

The side regulating plates 3A and 3B and the rear end regulating plate 5 are fixed to the cassette body 1.

The middle plate 2 is attached to the left and right side regulating plates 3A and 3B so as to be rotatable up and down around the support shafts 10A and 10B on the rear end side.

The right and left push-up springs 7A and 7B are arranged on the front end side of the intermediate plate 2 and are fixed to the cassette body 1.

The right and left separation claws 9A and 9B are supported by the rear shaft 1
Left and right side regulating plates 3A, 3B so as to be rotatable downward and vertically around 1A, 11B (one not shown).
Attached to.

FIG. 7 shows a case where the sheet material S stacked on the middle plate 2 is in a full state, and FIG. 8 shows a case where the sheet material S stacked on the middle plate 2 is in a small amount state. ing.

In the sheet material feeding system using this sheet cassette, the uppermost sheet of the sheet material S stacked on the middle plate 2 is pushed by the pushing force (biasing force) of the left and right pushing springs 7A and 7B. Is pressed against the paper feed roller 6.

As described above, when the uppermost sheet is pressed against the paper feed roller 6 and the feed roller 6 rotates clockwise (in the direction of the arrow), a predetermined conveying force is generated on the feed roller 6. The feeding roller 6 feeds the uppermost sheet. At this time, the top sheet is the left and right separation claws 9A and 9B.
Is separated into one.

The conveying force of the paper feed roller 6 is always constant whether the sheet material S stacked on the middle plate 2 is in the fully loaded state shown in FIG. 7 or in the small amount state shown in FIG. It must be the size of For this purpose, it is necessary that the push-up forces of the left and right push-up springs 7A and 7B change proportionally with the change in the stacking amount of the sheet material S on the middle plate 2.

That is, for example, when the sheet material is fully loaded as shown in FIG. 7 and when a small amount of sheet material is loaded as shown in FIG. 8, the pressing force (pressing force) of the uppermost sheet against the paper feed roller 6 is F1 (full load), F2 (full load). When loading a small amount), push-up springs 7A, 7B
, The lifting force of the sheet material S on the middle plate 2 is W1 (full load), F4 (full load), and F4 (full load).
If it is set to 2 (at the time of loading a small amount), the relationship must be F1 = F3-W1 = F2 = F4-W2.

The height (spring length) of the push-up springs 7A and 7B when the sheet material is fully loaded and when a small amount of sheet material is loaded is d.
Assuming that 1 (at full load) and d2 (at small load), the spring constant (the amount of change (N / mm) of the load with respect to the deformation amount) k of the push-up springs 7A and 7B is as follows.

K (N / mm) = {W1-W2} (N) /
{D1-d2} (mm) FIG. 9 shows the load (N) of each size sheet material when the present paper cassette is used for the A4 side sheet material and when the B4 side sheet material is used. And the remaining amount (sheets) in the cassette.

In the case of A4 size sheet material, {(spring lifting force F4)-(weight WA4 of remaining sheet material in cassette)} is always constant irrespective of the remaining amount in the cassette. As a result, the pressing force S1 applied to the uppermost sheet is always constant irrespective of the remaining amount in the cassette, and the conveying force of the sheet feeding roller 6 is stabilized.

In the case of a B4 size sheet material, the pressing force S2 is equal to FB4−WB4.

In the present paper feed cassette configured as described above, depending on the size of the sheet material S stacked on the middle plate 2, a pressing force and a spring constant corresponding to the sheet material size are provided. The lifting springs 7A and 7B are employed.

Therefore, if the A4 size sheet material S is temporarily stored in the sheet cassette for loading the B4 size sheet material S,
Is loaded, the push-up forces of the push-up springs 7A and 7B and the spring constant do not match the A4 size sheet material S.
(FB4-WA4) is not always constant regardless of the remaining amount in the cassette, and the pressing force S1 applied to the uppermost sheet changes.

As a result, the conveyance force of the paper feed roller 6 becomes unstable, and defective feeding or double feeding occurs.

[0020]

As described above, in the conventional sheet cassette shown in the prior art, the middle plate 2
Depending on the size of the sheet material S loaded thereon, the push-up springs 7A and 7B having a pushing force and a spring constant corresponding to the size of the sheet material are employed. It is impossible to load.

For this reason, a sheet cassette for each size, which has push-up springs 7A and 7B corresponding to the sheet material size, is required.

Therefore, the first invention has been made in view of the above-mentioned circumstances, and even when sheets of different sizes are stacked on the middle plate, the conveyance force of the sheet feeding roller is always constant.
It is an object of the present invention to provide a sheet cassette capable of stacking sheets of a plurality of sizes.

[0023]

SUMMARY OF THE INVENTION The present invention is directed to a middle plate for stacking sheet materials, a sheet material regulating plate for regulating the position of the sheet material stacked on the middle plate, and the middle plate. And a push-up spring for pushing up the sheet material stacked on the middle plate against the feed roller.

According to the present invention, in order to achieve the above object, the sheet material regulating plate is provided movably in accordance with the size of the sheet material loaded on the intermediate plate, and is connected to the sheet material regulating plate. An auxiliary push-up spring is provided which is movable to a position for pushing up the middle plate or a position not to push up with the movement of the sheet material regulating plate.

Further, according to the present invention, the auxiliary push-up spring is moved from a position where it does not push up the middle plate to a position where it is pushed up by the movement of the sheet material regulating plate when a large size sheet material is stacked on the middle plate. It is characterized by moving.

Further, in the present invention, the auxiliary push-up spring is formed in a wedge shape in cross section, and can be moved below the middle plate in accordance with the movement of the sheet material regulating plate to push up the middle plate. It is characterized by being provided in.

[0027]

According to the above construction, the sheet material regulating plate for regulating the position of the sheet material stacked on the middle plate is provided movably in accordance with the size of the sheet material stacked on the middle plate. An auxiliary push-up spring that is movable to a position where the middle plate is pushed up or a position where it is not pushed up with the movement of the sheet material regulation plate is connected to the sheet material regulation plate. Then, the sheet material regulating plate is moved according to the size of the sheet material, and the auxiliary push-up spring is pushed up together with the push-up spring to push up the middle plate to push the sheet material to the sheet feed roller, or to move the sheet material to a position where it is not pushed up. To

[0028]

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

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 show the configuration of a sheet cassette according to the first embodiment of the present invention. 1 is a perspective view, FIG. 2 is a plan view, and FIGS. 3 and 4 are longitudinal side views.

In the present paper cassette, the same members as those of the conventional paper cassette shown in the prior art are denoted by the same reference numerals, and the description of those which do not change in structure and function is omitted. I do.

In this paper feed cassette, the middle plate 2 is attached to the left and right side plates 1A and 1B of the cassette main body 1 so as to be rotatable up and down around support shafts 10A and 10B on the rear end side.

The left and right side regulating plates 3A, 3B are mounted so as to be movable in the width direction of the cassette body 1, that is, in the width direction of the sheet material.

The rear end regulating plate 5 is attached so as to be movable in the longitudinal direction of the cassette body 1, ie, in the sheet feeding direction.

Racks 12, 13, and 15 are provided on the left and right side regulating plates 3A and 3B and the rear end regulating plate 5, respectively.
An idler gear 16 rotatably mounted on the bottom plate of the cassette body 1 has these racks 12, 13, and 15.
Are engaged.

Accordingly, the left and right side regulating plates 3A and 3B and the rear end regulating plate 5 are interlocked via the idler gear 16.

Now, for example, when the left side regulating plate 3A is moved in the direction of arrow B, the right side regulating plate 3B moves in the direction of arrow A, and the rear end regulating plate 5 moves in the direction of arrow C. Conversely, when the left side regulating plate 3A is moved in the direction of arrow A, the right side regulating plate 3B moves in the direction of arrow B, and the rear end regulating plate 5 moves in the direction of arrow D. The same interlocking can be performed by operating the right side regulating plate 3B or the rear end regulating plate 5.

As described above, the left and right side regulating plates 3A, 3A
B and the rear end regulating plate 5 move, so that notches 17, 19, and 20 for guiding are provided on both left and right sides of the middle plate 2 and the center of the rear end.
Are formed.

This paper feed cassette is an A4 size sheet material S.
A and B4 size sheet materials SB can be stacked. As described above, when the left side regulating plate 3A is moved in the direction of arrow B, the left side regulating plate 3A,
The right side regulation plate 3B and the rear end regulation plate 5 can regulate the position of the A4 size sheet material SA stacked on the middle plate 2.

When the left side regulating plate 3A is moved in the direction of the arrow A, the left side regulating plate 3A, the right side regulating plate 3B and the rear end regulating plate 5 cause the B4 loaded on the middle plate 2 to move. The position of the sheet material SB having the size can be regulated.

Normally, the middle plate 2 is pushed up by left and right push-up springs 7A and 7B as shown in FIG.
When the rear end regulating plate 5 moves in the direction of the arrow D, the (fixed) wedge-shaped auxiliary push-up spring (leaf spring) 21 attached to the front end of the rear end regulating plate 5 as shown in FIG. The middle plate 2 is located between the left and right push-up springs 7A and 7B below the middle plate 2, and the middle plate 2 is pushed up by the left and right push-up springs 7A and 7B and the auxiliary push-up spring 21.

FIG. 3 shows a state in which an A4 size sheet material SA is stacked on the middle plate 2. In this case, the middle plate 2 is pushed up by left and right push-up springs 7A and 7B having a pushing force and a spring constant suitable for the A4 size sheet material SA.

FIG. 4 shows a state in which a B4 size sheet material SB is stacked on the middle plate 2. In this case, as described above, the middle plate 2 includes left and right push-up springs 7A and 7B,
It is pushed up by the auxiliary push-up spring 21. The auxiliary push-up spring 21 has a push-up force and a spring constant (a portion indicated by hatching in FIG. 9) that are insufficient with only the left and right push-up springs 7A and 7B when the B4 size sheet material SB is stacked. I have.

Next, a second embodiment of the present invention will be described.

FIG. 5 shows a main configuration of a sheet cassette according to the second embodiment of the present invention.

In this paper feed cassette, an auxiliary push-up spring 22 composed of a coil spring is provided in place of the auxiliary push-up spring 21 composed of a leaf spring.

When the rear end regulating plate (not shown) moves in the direction of arrow D, the auxiliary push-up spring 22 enters a state below the middle plate 2 in a compressed state as shown by a dotted line.

In this case, since the auxiliary push-up spring 22 is easily buckled, a guide member 23 for preventing buckling is provided here.

The sheet cassettes shown in the first and second embodiments have a configuration in which A4 size sheet material SA and B4 size sheet material SB can be stacked. And the like can be stacked.

When a plurality of auxiliary push-up springs are provided, each auxiliary push-up spring may be moved by a side regulating plate.

The left and right push-up springs 7A and 7B can also be leaf springs.

[0051]

As described above, in the paper feed cassette of the present invention, the sheet material regulating plate is moved according to the size of the sheet material, and the middle plate is pushed up by the push-up spring and the auxiliary push-up spring. Sheet material can be pressed against the paper feed roller, so that the conveyance force of the paper feed roller is always constant,
It is possible to stack sheet materials of a plurality of sizes in one cassette.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a configuration of a paper feed cassette according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway plan view showing the configuration of the paper feed cassette.

FIG. 3 is a vertical sectional side view showing the configuration of the paper feed cassette (when A4 size sheet material is loaded).

FIG. 4 is a vertical sectional side view showing a configuration of the paper feed cassette (when a B4 size sheet material is loaded).

FIG. 5 is a vertical sectional side view showing a configuration of a main part of a paper feed cassette according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing the configuration of a conventional paper feed cassette.

FIG. 7 is a vertical sectional side view showing the configuration of the paper feed cassette (when sheets are fully loaded).

FIG. 8 shows the configuration of the paper feed cassette (when a small amount of sheet material is loaded).
FIG.

FIG. 9 is a diagram showing the relationship between the load and the remaining amount of sheet material in the cassette when the same sheet cassette is applied to A4 size sheet material and when the same sheet cassette is applied to B4 size sheet material.

[Explanation of symbols]

 2 Middle plate 3A, 3B Side regulating plate (sheet material position regulating plate) 5 Rear end regulating plate (sheet material position regulating plate) 6 Feed roller 7A, 7B Push-up spring 21 Auxiliary push-up spring SA A4 size sheet material SB B4 size sheet material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 1/24 B65H 1/04 320 B65H 1/12 310 G03G 15/00 516 H04N 1/00 108

Claims (3)

(57) [Claims] 1. An intermediate plate for stacking sheet materials, a sheet material regulating plate for regulating the position of the sheet material stacked on the intermediate plate, and a plate for pushing up the intermediate plate to cover the intermediate plate. And a push-up spring for pressing the sheet material stacked on the sheet feeding roller, wherein the sheet material regulating plate is movable according to the size of the sheet material stacked on the middle plate. And an auxiliary push-up spring connected to the sheet material regulating plate and movable to a position for pushing up the middle plate or a position not to push up with the movement of the sheet material regulating plate. Paper cassette. 2. An auxiliary push-up spring moves from a position where the middle plate is not pushed up to a position where it is pushed up by a movement of the sheet material regulating plate when a large-sized sheet material is stacked on the middle plate. The paper feed cassette according to claim 1, wherein: 3. The auxiliary push-up spring is formed in a wedge shape in cross section, and is provided so as to move below the middle plate in accordance with the movement of the sheet material regulating plate so as to push up the middle plate. 3. The sheet cassette according to claim 2, wherein: