JPH11180568A - Sheet feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regulate the feed pressure to the optimum by the width of a sheet loaded by providing an elastic member for energizing a feed middle plate toward a feed roller, and making the energizing force of the elastic member adjustable by the position of a sheet width regulating means. SOLUTION: A feed middle plate 13 is arranged under a feed roller 12 on the downstream side of a tray 11, and constituted in such a manner as to be rotatable in the direction making contact with and separating from the feed roller 12 around a fulcrum 13a. A spring 15 which is an elastic member is mounted under the feed middle plate 13, and energized toward the feed roller 12. A pressurizing plate 18 which is a support means for supporting the spring 15 is mounted under the spring 15 or on the opposite side to the feed middle plate 13. The pressurizing plate 18 is mounted in such a manner as to be rotatable in the arrowed direction from a first position fixed by a stopper around a shaft 18c. The pressurizing plate 18 supports the spring 15 in a spring holding part 18a on one end and has a pressurizing lever 18b on the other end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-feeding means such as a laser beam printer, a copying machine, and a facsimile machine.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a laser beam printer, a copying machine, and a facsimile apparatus, a feeding cassette for loading frequently used size sheets and a sheet or feeding cassette for less frequently used sizes are used. And multi-feeding means for feeding thick paper or envelopes which are difficult to feed.

The multi-feeding means includes a tray serving as a sheet stacking means, a feeding roller for sending out the sheets stacked on the tray, a feeding plate for urging the sheet to the feeding roller, and a feeding roller. In many cases, a separation pad system composed of a separation pad biased to the above is adopted.

In such a configuration, the sheets stacked on the tray are urged by a feeding roller at a predetermined feeding pressure by a feeding plate, and are sequentially fed with the rotation thereof. Then, the sheet is separated into a single sheet by passing through a nip between a feeding roller and a separation pad urged by the feeding roller at a predetermined separation pressure, and fed.

In order to reduce the installation area of the main body of the image forming apparatus, it is also common to arrange a part of the tray so as to be expandable and contractable or to store the entire tray inside the main body. It is being done. Furthermore, a sheet width regulating plate that is slidable in the width direction of the sheet on the tray and the position in the width direction is regulated according to the size of the sheet to be used to prevent skew of the sheet is also widely used. Have been.

[0006]

However, in the above-mentioned conventional multi-feeding means, it is necessary to separate and feed from special use sheets such as envelopes and OHP sheets from thick paper to thin paper due to its nature. . The feeding pressure and separation pressure of thin paper such as plain paper may be small, while the feeding pressure that satisfies the feeding performance for all types of sheets, because thick paper and OHP sheets require large pressure. In addition, it was difficult to set the separation pressure.

In particular, when feeding an envelope, it is necessary to separate and feed while crushing the air inside the envelope closed in a bag shape. Therefore, the feeding pressure generated between the plate during feeding and the feeding roller. However, there is a problem that the feeding is not effectively used, and a feeding failure is likely to occur. However, if the feeding pressure is set to a large value as a countermeasure, the conveying force of plain paper increases more than necessary, and as a result, poor separation of plain paper tends to occur. As described above, there is a problem that it is difficult to set the feeding conditions to achieve both the feeding performance of the envelope and the separating performance of the plain paper.

According to the present invention, a supporting means for supporting an elastic member for urging the feeding plate against the feeding roller is provided so as to be movable, and the position of the supporting means is controlled in accordance with the size of the sheet so that the feeding plate is controlled. It is an object of the present invention to provide an image forming apparatus capable of controlling an urging force.

[0009]

In order to solve the above-mentioned problems, a configuration according to the present invention comprises a sheet stacking unit for stacking sheets, and a sheet width regulating unit movably mounted in the width direction of the sheets. Means, a feeding roller for sending out sheets stacked on the sheet stacking means, a feeding plate attached detachably to the feeding roller via the sheet, and the feeding plate. An elastic member for urging toward the feeding roller, wherein an urging force of the elastic member can be adjusted by a position of the sheet width regulating means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the multi-feeding unit of the image forming apparatus according to the present embodiment, FIG. 2 is a diagram showing a state in which plain paper is loaded on the multi-feeding unit, and FIG. 3 is an envelope loaded on the multi-feeding unit. FIGS. 4 and 5 are partial perspective views illustrating the operation of the multi-feeding unit. FIG. 6 is a diagram illustrating the overall configuration of the image forming apparatus.
FIG. 7 is a diagram showing a state in which the multi-feeding means is stored.
In the present embodiment, a laser beam printer will be described as an example of the image forming apparatus.

First, a schematic configuration of the image forming apparatus will be described with reference to FIGS. At the lower portion of the main body 1 of the image forming apparatus, cassettes 2 for stacking and storing the recording sheets S are attached in two upper and lower stages. These cassettes 2 can be attached to and detached from the front side of the apparatus to supply recording sheets S.

A pickup roller 3 is provided near the cassette 2.
And a retard roller 4. The sheet S stacked on the cassette 2 is sent out from the uppermost side by the pickup roller 3, and is conveyed while being separated one by one by the retard roller 4. The recording sheet S separated and fed from the cassette 2 is conveyed by the conveying roller pair 5, the tip of which strikes the nip portion of the registration roller pair 6, which has stopped rotating, to correct the skew, and then image formation is performed at a predetermined timing. To the department.

The image forming section is provided with a process cartridge 7 containing known process means for image formation, which is detachably mounted on the apparatus main body 1. The recording sheet S on which the image has been transferred by the process cartridge 7 is fixed by applying heat and pressure by a fixing device 8, and is discharged to a discharge tray 10 formed on the upper surface of the device by a discharge roller pair 9.

A multi-feeding means A is provided on a side surface of the apparatus main body 1 in order to feed a recording sheet S of a type not mainly stored in the cassette 2. The multi-feeding means A is provided so as to be housed in the apparatus main body 1 as shown in FIG. 7, and is pulled out and used as shown in FIG.

When the multi-feeding means A is used, the tray 11 of the multi-feeding means A is interlocked by opening the multi-cover 23 which forms a part of the outer cover of the apparatus main body 1. Around the center. This allows the tray
11 protrudes from the side surface of the apparatus main body 1 so that the recording sheets S can be stacked. Further, an auxiliary tray 22 is stored in the tray 11, and the recording sheet S having a size longer than the tray 11 is drawn out along a guide rail (not shown).
It is configured to be able to support

The details of the multi-feeding means A will be described with reference to FIG. The multi-feeding unit A includes a tray 11 serving as a sheet stacking unit, and a recording sheet S stacked on the tray 11.
Roller, which feeds the recording sheet S to the feed roller 12, and a separation pad 14 which is urged by the feed roller 12, adopts a separation pad system. doing.

As shown in FIG. 2, a pair of width regulating plates 16 as sheet width regulating means are attached to the tray 11 so as to be movable in the width direction of the recording sheet S. This width regulating plate 16
Has a function of preventing the skew of the recording sheet S by sliding the recording sheet S in a direction substantially perpendicular to the conveying direction of the recording sheet S to adjust the position according to the width of the recording sheet S.

A lever member 19 is provided below the tray 11 and substantially opposite the width regulating plate 16. The lever member 19 is fixed to the width regulating plate 16 via the slit 20 of the tray 11, and is configured to move in conjunction with the width regulating plate 16. As shown in FIG. 4, a pressing portion 19a is formed at the tip of the lever member 19, and a pressing lever 19 described later is provided.
It is arranged at a position substantially opposite to 18b.

The feeding plate 13 is disposed downstream of the tray 11 and below the feeding roller 12 as shown in FIG.
It is configured to be rotatable about 13a in a direction in which it comes into contact with and separates from the feed roller 12. A spring 15 as an elastic member is attached below the plate 13 during feeding, and is urged toward the feeding roller 12.

Further below the spring 15, that is, on the side opposite to the plate 13 during feeding, a pressure plate 18 as a support means for supporting the spring 15 is attached. The pressure plate 18 is attached to the shaft 18c so as to be rotatable in a direction indicated by an arrow from a first position (a position indicated by a dashed line in FIG. 1) fixed by a stopper (not shown). The pressing plate 18 has a spring holding portion 18a at one end.
At the other end, and a pressure lever 18 at the other end.
b.

Both ends of the spring 15 are held between the feeding plate 13 and the pressing plate 18, and the biasing force acts in a direction to separate the feeding plate 13 and the pressing plate 18. For this reason, the pressing plate 18 is normally urged to the first position.

When ordinary recording sheets S such as thin paper are fed by the multi-feeding means A constructed as described above, the recording sheets S are stacked on the tray 11 as shown in FIG. Is moved along both sides of the recording sheet S. At this time, as shown in FIG. 4, the pressing portion 19a of the lever member 19 is not in contact with the pressing lever 18b.

The rotation of the feeding plate 13 is controlled by a cam (not shown). When the feeding plate 13 is lifted, the uppermost portion of the recording sheets S stacked on the tray 11 is fed to the feeding roller. It is urged to 12 and fed to the separation pad 14. Subsequently, the recording sheet S is separated one by one by the separation pad 14 and the feeding roller 12, and is sent to the above-described image forming unit via the conveyance path 17 and the pair of registration rollers 6.

Next, the procedure and the operation when the thick sheet envelope S1 is fed by the multi-feeding means A will be described. As shown in FIG. 3, the envelope S1 is stacked on the tray 11, and the width regulating plate 16 is moved according to the width of the envelope S1.
Here, the width dimension of the pressing lever 18b is set so as to engage with the pressing portion 19a of the lever member 19 only when the position of the width regulating plate 16 is set to the width of the envelope S1.

Therefore, as shown in FIG. 5, the pressing portion 19a of the lever member 19 moved in conjunction with the width regulating plate 16 comes into contact with the pressing lever 18b and is pushed downward, and the lever member 19 is moved to the second position. (The position indicated by the solid line in FIG. 1). Accordingly, when the user sets the width regulating plate 16 to the size of the envelope S1, the spring holding portion 18a rotates about the shaft 18c and the spring 15
And the feeding pressure at which the feeding plate 13 urges the recording sheet S against the feeding roller 12 increases.

As described above, since the feeding pressure can be adjusted by the position of the width regulating plate 16, the feeding pressure can be selectively set high only when the envelope S1 is fed. . Therefore, both the feeding performance of the envelope S1 and the separating performance of the recording sheet S, which is plain paper, can be compatible.

[Second Embodiment] Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.
FIG. 8 is a cross-sectional view of the multi-feeding unit of the image forming apparatus according to the present embodiment, and FIGS. 9 and 10 are partial perspective views illustrating the operation of the multi-feeding unit. The same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

In the multi-feeding means B according to this embodiment, the pressing plate 24 is supported so as to be able to move in parallel along the guide shaft 21. The guide shaft 21 is fixed substantially parallel to the pressing direction of the spring 15, and supports the pressing plate 24 substantially vertically.

The pressing plate 24 is mounted so as to be movable in the direction of the arrow from a first position (a position indicated by a dashed line in FIG. 8) regulated by a stopper (not shown). Similarly to the first embodiment, the pressing plate 24 supports the spring 15 at the spring holding portion 24a at one end and the pressing lever 24b at the other end.
have.

On the other hand, a lever member 19 interlocked with the width regulating plate 16
Is located below the pressure lever 24b. When the width regulating plate 16 is set to the width of the ordinary recording sheet S as shown in FIG. 9, the pressing portion 19a does not come into contact with the pressure lever 24b, and as shown in FIG. When set to the width of the envelope S1, it is configured to contact the lower surface of the pressing portion 19a.

As a result, when feeding the envelope S1, the pressure plate 24 can be moved in parallel from the first position to the second position (the position indicated by the solid line in FIG. 8). Can increase the feeding pressure for urging the recording sheet S against the feeding roller 12.

With the above configuration, the posture of the pressing plate 24 with respect to the spring 15 can be maintained substantially vertical at both the first and second positions, and the spring 15 is reliably supported, and the feeding is always stable. Pressure can be obtained.

[Third Embodiment] Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.
11 is a main cross-sectional view of the image forming apparatus according to the present embodiment, FIG. 12 is a cross-sectional view showing a state where the auxiliary tray of the multi-feeding unit is stored, and FIG. FIG. Portions that are the same as those in the first or second embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

As described in the first embodiment, when an image is formed on a large recording sheet S, the tray 11
The recording sheet S is stacked by pulling out the auxiliary tray 22 stored in the inside. However, since the auxiliary tray 22 is slid along the guide rails, it is often difficult to configure the sheet stacking surface of the tray 11 and the auxiliary tray 22 as a continuous plane due to the restrictions of the guide rails.

In this case, the stacked recording sheets S
Since the recording sheet S is bent at a discontinuous point between the auxiliary tray 22 and the recording sheet S, the conveyance resistance of the recording sheet S increases, and the risk of inducing feeding failure increases. In this embodiment,
The above problem is solved by adopting a configuration in which the switching of the feeding pressure is performed in conjunction with the drawing of the auxiliary tray 22.

In the multi-feeding means C according to this embodiment shown in FIG. 11, the pressing plate 24 has a spring similar to the second embodiment.
It is attached to a guide shaft 21 fixed substantially parallel to the pressing direction 15 so as to be able to move in parallel (in the direction of the arrow shown in FIG. 13). An auxiliary pressure spring 25 fixed substantially parallel to the guide shaft 21 is attached below the pressure plate 24, and urges the pressure plate 24 toward the plate 13 during feeding. Here the auxiliary pressure spring
The urging force of 25 is set larger than the urging force of the spring 15.

As shown in FIG. 12, a pressing portion 22a is formed at an end of the auxiliary tray 22 on the pressing plate 24 side. In a state where the auxiliary tray 22 is stored, the pressing portion 22a contacts the pressing lever 24b of the pressing plate 24, and presses down the pressing plate 24 against the spring pressure of the auxiliary pressing spring 25. Therefore, the feeding plate 13 is in a state of being urged only by the spring 15.

On the other hand, in a state where the auxiliary tray 22 is pulled out and the large-sized recording sheets S are stacked as shown in FIG. 13, the pressing plate 24 is released from the pressing portion 22a of the auxiliary tray 22, and the auxiliary pressing spring It slides toward the feeding plate 13 by the urging force of 25. That is, the feeding plate 13 is
In addition to this, the state is also urged by the auxiliary pressing spring 25, and the feeding pressure of the multi-feeding means C increases.

With the above configuration, the switching of the feeding pressure can be performed in conjunction with the drawing out and storage of the auxiliary tray 22. Thus, even when a large-sized recording sheet S is fed, a stable feeding operation can be performed with a large feeding pressure.

[0040]

As described above, in the sheet feeding apparatus and the image forming apparatus according to the present invention, the urging force of the elastic member for urging the plate during feeding is controlled according to the position of the sheet width regulating plate. Thereby, the feeding pressure can be optimally adjusted according to the width of the stacked sheets. Here, in general, utilizing the fact that the width of the envelope is smaller than that of the plain paper, the feeding pressure is set to be large when the width regulating plate is set to the width of the envelope, so that the feeding performance of the envelope and the normal It is possible to make the apparatus compatible with the paper separating performance.

Further, by controlling the urging force of the elastic member in conjunction with pulling out and storing of the auxiliary stacking means, a large feeding pressure can be obtained when a large-sized sheet is fed. A sending operation can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a multi-feeding unit of an image forming apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating a state in which plain paper is stacked on a multi-feeding unit.

FIG. 3 is a diagram illustrating a state where envelopes are stacked on a multi-feeding unit.

FIG. 4 is a partial perspective view illustrating the operation of the multi-feeding unit.

FIG. 5 is a partial perspective view illustrating the operation of the multi-feeding unit.

FIG. 6 is a diagram illustrating an overall configuration of an image forming apparatus.

FIG. 7 is a diagram showing a state in which the multi-feeding means is stored.

FIG. 8 is a sectional view of a multi-feeding unit of the image forming apparatus according to the second embodiment.

FIG. 9 is a partial perspective view illustrating the operation of the multi-feeding unit.

FIG. 10 is a partial perspective view illustrating the operation of the multi-feeding unit.

FIG. 11 is a main cross-sectional view of an image forming apparatus according to a third embodiment.

FIG. 12 is a cross-sectional view illustrating a state in which an auxiliary tray of the multi-feeding unit is stored.

FIG. 13 is a diagram illustrating a state where an auxiliary tray of the multi-feeding unit is pulled out.

[Explanation of symbols]

 A: Multi-feeding means B: Multi-feeding means C: Multi-feeding means S: Recording sheet S1 ... Envelope 1 ... Device body 2 ... Cassette 3 ... Pick-up roller 4 ... Retard roller 5 ... Transport roller pair 6 ... Registration roller pair 7: Process cartridge 8: Fixing device 9: Discharge roller pair 10: Discharge tray 11: Tray 12: Feeding roller 13: Feeding plate 13a: Support point 14: Separation pad 15: Spring 16: Width control plate 17: Transport path 18 ... Pressing plate 18a ... Spring holding part 18b ... Pressing lever 18c ... Shaft 19 ... Lever member 19a ... Pressing part 20 ... Slit 21 ... Guide shaft 22 ... Auxiliary tray 22a ... Pressing part 23 ... Multi cover 24 ... Pressing plate 24a ... Spring holder 24b… Pressure lever 25… Auxiliary pressure spring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Izumi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takashi Kuwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Judge Sekiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (8)

[Claims] 1. A sheet stacking unit for stacking sheets, a sheet width regulating unit movably attached in a width direction of the sheet, and a feeding roller for sending out the sheets stacked on the sheet stacking unit. A sheet feeding plate attached to the sheet feeding roller via the sheet so as to be able to be separated from and connected to the sheet feeding roller, and an elastic member for urging the sheet feeding plate toward the sheet feeding roller. A sheet feeding device, wherein a biasing force of said elastic member is adjustable by a position of a regulating means. 2. The sheet feeding device according to claim 1, wherein the urging force of the elastic member is increased when the sheet width regulating means is moved in a narrowing direction. 3. A support means for sandwiching the elastic member with the plate during feeding is provided, the support means is configured to be movable in a biasing direction of the elastic member, and the position of the sheet width regulating plate is adjusted by the position of the sheet width regulating plate. 3. The sheet feeding apparatus according to claim 1, wherein the position of the supporting means is configured to be regulated. And a lever member which moves in conjunction with said sheet width regulating means, and wherein said lever member abuts said supporting means when said sheet width regulating means is at a predetermined position. 4. The sheet feeding device according to claim 3, wherein the position is regulated. 5. A sheet stacking means for stacking sheets, an auxiliary stacking means mounted so as to be housed in the sheet stacking means, a feeding roller for sending out sheets stacked on the sheet stacking means, A feeding plate attached to the feeding roller via the sheet so as to be detachable from the feeding roller, and an elastic member for urging the feeding plate toward the feeding roller; A sheet feeding device, wherein an urging force of the elastic member is adjustable between a drawer position and a storage position. 6. The sheet feeding device according to claim 5, wherein a biasing force of said elastic member is increased when said auxiliary stacking means is pulled out to a pull-out position. 7. A supporting means for supporting the elastic member on a side of the elastic member opposite the plate during feeding, wherein the supporting means is configured to be movable toward the elastic member, and the auxiliary loading means is provided. 7. The sheet feeding device according to claim 5, wherein a part of the auxiliary stacking means abuts on the supporting means when the apparatus is at the storage position to regulate the position of the supporting means. Feeder. 8. An image forming apparatus, comprising: the sheet feeding device according to claim 1; and an image forming unit that forms an image on a sheet fed from the sheet feeding device. .