JP3176455B2 - Paper feeder with bottom plate lifting mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device applied to an image forming apparatus such as a facsimile, a laser printer, a copying machine, etc., and more particularly to a bottom plate elevating mechanism for the sheet feeding device.

[0002]

2. Description of the Related Art As is well known, when a cut sheet is used as a transfer material of an image forming apparatus, a sheet feeding device such as a sheet cassette is provided with a bottom plate elevating mechanism, and the sheet is fed to a sheet feeding section. The sheet is pressed against a paper feed roller disposed above to convey the sheet into the apparatus.

As the bottom plate elevating mechanism, a bottom plate elevating mechanism using a motor, a bottom plate elevating mechanism using a spring, and the like are known, corresponding to various sheet feeding devices.

[0004]

However, since the bottom plate elevating mechanism using a motor uses electric parts, it is necessary to additionally have control means for the electric parts, so that the structure must be complicated.

Further, since the bottom plate raising mechanism using a spring is merely a mechanism for raising the bottom plate, an operation of lowering the bottom plate by the operator himself or a mechanism for lowering the bottom plate is additionally required. .

FIG. 8 shows a bottom plate elevating mechanism in a sheet feeding device of a type in which a sheet feeding tray is inserted along a sheet conveying direction.
As shown in FIG. 2, the rib 1 attached to the image forming apparatus 17 is
8, a bottom plate lowering mechanism that presses a projection 15a provided on the bottom plate 15 in the paper feed tray 16 to push down the bottom plate 15 is adopted in many cases.

However, in the case of a front-loading type paper feeding device in which a paper feeding tray is inserted in a direction perpendicular to the paper conveying direction, for example, the bottom plate raising operation is performed after the cassette has been completely mounted, that is, Unless the paper feeder is completely housed inside the main body over the entire width,
For example, in the case of inserting A4 size paper in the vertical direction, the loading distance becomes long, and unlike a paper feeding device of a type in which a paper feeding tray is inserted along the paper transporting direction, a specific I have a problem.

For example, when the above-described bottom plate lowering mechanism is employed as a front loading type bottom plate lifting mechanism,
The projection of the bottom plate increases the size of the device, which hinders space saving of the machine.

[0009] Another bottom plate lifting mechanism is disclosed in
No. 3-4930 has been proposed. According to the gazette disclosed in the publication, the bottom plate elevating mechanism moves a cassette holding member, which is located at the back side in the sheet cassette insertion direction and operates by abutting the sheet cassette, and a sheet loaded in the sheet cassette. A conveying pressure pressing member for applying a conveying pressure to the sheet pushed up from below; and a spring member provided between the conveying pressure pressing member and the cassette pressing member, wherein the spring member is formed by inserting a paper feed cassette. The transport pressure pressing member is operated by the operation of the cassette pressing member, and a spring force is applied between both members. The cassette holding member, the conveying pressure pressing member, and the spring member are all attached to the apparatus main body due to the movement when the conveying pressure is applied to the stacked sheets in the sheet feeding cassette.

However, in this mechanism, the position where the conveying pressure pressing member (bottom plate pushing-up member) applies the conveying pressure to the paper is always at a fixed distance from the support shaft, regardless of the paper size. Therefore, when the mechanism is applied to an image forming apparatus in which the paper feed reference is the center, depending on the paper size, the position where the paper comes into contact with the paper feed roller (feed roller) and the conveyance given from below the paper There is a considerable deviation from the pressure application position, which may cause skew.

An object of the present invention is to solve the above-mentioned problem by providing a sheet feeding device of a type in which a sheet feeding tray is inserted in a direction perpendicular to a sheet conveying direction, which is easy for an operator to use and special control means. It is an object of the present invention to provide a bottom plate elevating mechanism that does not require a sheet and does not cause a bias in sheet lifting and pressing.

[0012]

According to the present invention, there is provided, in accordance with the present invention, a paper feed tray inserted into an image forming apparatus in a direction perpendicular to a paper transport direction, and a paper feed tray disposed in the paper feed tray. A sheet feeder having a bottom plate, and a sheet feed roller provided inside the image forming apparatus being brought into contact with the stacked transfer sheets by raising the bottom plate to feed the transfer sheet; A refraction member extending in the front direction and having a fulcrum at a portion on the front side in the paper feed tray insertion direction and corresponding to the position of the paper feed roller and pushing up the bottom plate by refraction accompanying the insertion operation of the paper feed tray; A bottom plate elevating mechanism comprising a stopper means for pressing a rear end portion of the member in the paper feed tray insertion direction toward the paper feed tray and a paper feed tray lock mechanism for fixing the paper feed tray at a predetermined position is provided.

The refracting member is preferably formed such that the refracting portion abuts on the bottom plate within the length of the sheet feeding roller in the sheet feeding tray insertion direction.

It is preferable that a member for reducing the resistance when the bottom plate is raised and lowered is provided in the bending portion of the bending member.

It is more convenient if the stopping means pushes out the paper feed tray in the pull-out direction when the tray lock mechanism is released.

The image forming apparatus includes a paper feed tray inserted into the image forming apparatus in a direction perpendicular to the paper conveying direction, and a bottom plate disposed in the paper feed tray. In a paper feeding device that transports a transfer paper by bringing a paper roller into contact with a stack of transfer papers, the paper feeder has a fixed fulcrum end for applying a pushing force near the center on the lower surface side of the bottom plate and extends in the paper feed tray insertion direction. A push-up member that rises with the insertion operation of the paper tray, a stopper that presses the other end of the push-up member toward the front of the paper tray, and a paper tray lock mechanism that fixes the paper tray at a predetermined position. The above-mentioned problem can be solved even if a bottom plate elevating mechanism is provided.

Provided that a plurality of push-up members are provided, fulcrums of the push-up members on the bottom plate are provided in parallel in the direction of insertion of the paper feed tray, and the combined push-up force is located near the center of the bottom surface of the bottom plate. Is preferred.

The image forming apparatus includes a paper feed tray inserted into the image forming apparatus in a direction perpendicular to the paper conveying direction, and a bottom plate disposed in the paper feed tray. In a paper feeder that transports a transfer paper by bringing a paper roller into contact with a stack of transfer papers, the paper feeder extends in the paper feed tray insertion direction below the bottom plate and has a fulcrum at a front end in the paper feed tray insertion direction. An elastic bending member that bends with the insertion operation of the paper feed tray, a stop member that abuts on the other end of the elastic bending member during the paper tray insertion operation, and a paper tray lock that fixes the paper tray at a predetermined position The above problem is also solved by providing a bottom plate elevating mechanism comprising a mechanism.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an embodiment shown in the drawings.

In FIG. 1, the paper feed tray 1 slides on and out of rails 6a and 6b mounted in the main body of the image forming apparatus. The transfer paper accommodated in the paper feed tray 1 can be conveyed in the direction of arrow A by the paper feed roller 5 after the tray is mounted. As is apparent from FIG. 2, a bottom plate 7 is provided at a lower portion inside the paper feed tray 1, and the transfer paper is stacked on the bottom plate 7.

The bottom plate elevating mechanism according to the present invention basically includes
The feeding tray 1 includes a bending member 4 extending in the tray insertion direction inside the tray 1 and a pressure spring 3 fixedly disposed in the body in the insertion direction. The bending member 4 composed of two rod-shaped members has a rotation fulcrum 4a on the front side of the paper feed tray 1 and rotatably connects the two rod-shaped members at a point 4b near the middle of the transfer paper width. The light is refracted at the point 4b. The pressure spring 3 comes into contact with the rear end 4 c of the bending member 4, and bends the bending member 4 as the paper feed tray 1 is pushed. The paper feed tray 1 is provided with a paper feed tray lock mechanism described later.

When the sheet feeding tray 1 is inserted into the image forming apparatus by the operator, the bending member 4 comes into contact with the pressing spring 3 at the end face 4c, and is rotated about the fulcrum 4a by the pressing force of the pressing spring 3. Moves and refracts at point 4b. By such an operation, the bottom plate 7 on which the transfer paper is loaded is raised, and the top transfer paper is brought into contact with the paper feed roller 5, and
It is in a state where it can be transported. At this time, the paper feed tray 1 is locked by a paper feed tray lock mechanism described later, and is installed so as not to shift in the direction of arrow B.

When the paper feed tray lock mechanism is released by the operator, the refracting member 4 rotates about the fulcrum 4a in the opposite direction to the above, and the refraction at the point 4b is restored to a linear shape. Lower the bottom plate 7.

In FIG. 3, which shows the state of the bottom plate lifted by the movement of the bottom plate elevating mechanism, the bending point 4b of the bending member 4 is located directly below the sheet feeding roller 5, and is in the width direction of the sheet feeding roller 5, ie, in the width direction. , Are set to move along the paper feed tray insertion direction. Here, a sliding roller 9 is provided at the refraction point 4 b of the refraction member 4, and slides while rotating on the bottom plate 7. When the refraction point 4b of the refraction member 4 rotates and slides in the width direction of the sheet feed roller 5, the bottom plate 7 receives pressure at a certain location, and skew due to bias of the pressure can be prevented. Further, the provision of the sliding rollers 9 improves the slidability between the bottom plate 7 and the refraction member 4, smoothens the lifting and lowering operation of the bottom plate 7, and reduces the burden on the operator in taking the paper tray in and out.

In this embodiment, the sliding roller 9 is used as a resistance reducing member when the bottom plate is raised and lowered.
When Mylar (trade name) is applied or grease is applied instead of the above, almost the same effect can be obtained though it is slightly inferior.

A paper feed tray lock mechanism for fixing the mounted paper feed tray 1 so as not to shift is shown in FIGS.
As shown in the figure, the projection 8 provided on the paper feed tray 1 side
And a lever 10 attached to the apparatus body and a spring 11 hooked on the lever. When releasing the paper feed tray lock mechanism, as shown in FIG. 4, when the lever 10 is pushed up in the direction C, the engagement between the lever 10 and the projection 8 is released, and the paper feed tray 1 is pressed by the pressing force of the pressure spring 3. Is pushed out in the B direction. With such a mechanism, the operator can easily pull out the tray simply by pulling up the lever 10.

FIG. 5 shows a bottom plate elevating mechanism having another structure.

The bottom plate push-up member 12 is mounted near the center of the lower surface of the bottom plate 7 in the paper feed tray 1. That is, the rotation fulcrum 12a of the bottom plate pushing-up member 12 is
Exists in almost the central area of Bottom plate push-up member 12
Has a free end protruding deeper in the tray insertion direction. By inserting the paper feed tray 1, the free end of the bottom plate pushing-up member 12 comes into contact with the pressing spring 3, and the pressing force of the pressing spring 3 causes the bottom plate pushing-up member 12 to move the bottom plate 7 at the pivot 12 a. Then, the transfer paper is brought into contact with a paper feed roller (not shown). At this time, the paper feed tray 1 is locked by the paper feed tray lock mechanisms 8, 10, and 11 so that the paper feed tray 1 does not shift in the direction of arrow B or pop out.
With such a configuration, the bottom plate 7 can be pressed at the same location,
There is no twist of the bottom plate, and stable paper feeding can be performed.

FIG. 6 shows an example in which the configuration of FIG. 5 is improved.

The bottom plate push-up member 12 and the bottom plate push-up member 13 are mounted on the lower surface side of the bottom plate 7 in the paper feed tray 1 in a direction perpendicular to the paper conveyance direction, that is, substantially symmetrically in the tray insertion direction. I have. That is, the rotation fulcrum 12a of the bottom plate pushing member 12 and the bottom plate pushing member 13
The rotation fulcrum 13a exists so as to sandwich substantially the center of the bottom plate 7. The free ends of the bottom plate push-up members 12 and 13 protrude deeper in the tray insertion direction. By inserting the paper feed tray 1, the bottom plate lifting members 12, 1,
The free ends of the bottom plate 3 abut against the pressure springs 3a and 3b, respectively, and the pressing force of the pressure springs 3a and 3b causes the bottom plate pushing-up member 12 to turn at the rotation fulcrum 12a, and the bottom plate pushing-up member 13 to turn at the rotation fulcrum 13a. Then, the transfer paper is brought into contact with a paper feed roller (not shown). At this time, the paper feed tray 1 is locked by the paper feed tray lock mechanisms 8, 10, and 11 so that the paper feed tray 1 does not shift in the direction of arrow B or pop out. With such a configuration, the bottom plate 7 can always be pressurized at the same position, and the bottom plate is not twisted, so that more stable paper feeding can be performed.

FIG. 7 shows a bottom plate elevating mechanism having still another configuration.

A leaf spring 14 extends below the bottom plate 7 in the paper feed tray 1 over the entire length of the tray in the insertion direction. The leaf spring 14 is provided at a fulcrum 14a on the front side of the sheet feeding tray.
The free end of the leaf spring 14 protrudes from the sheet feed tray at the back side in the insertion direction. By inserting the paper feed tray 1, the free end of the leaf spring 14 comes into contact with the pressure spring 3, and the pressure spring 3 and the leaf spring 14
The bottom plate 7 is raised by the respective pressing forces, and the transfer paper is brought into contact with a paper feed roller (not shown). With such a configuration, the bottom plate elevating mechanism can be formed more easily.

[0033]

According to the first aspect of the present invention, in a sheet feeding device having a so-called front loading type sheet feeding tray, the sheet feeding device extends in the sheet feeding tray insertion direction below the bottom plate and is located in front of the sheet feeding tray insertion direction. A deflecting member that has a fulcrum at the side corresponding to the position of the paper feed roller and pushes up the bottom plate by refraction accompanying the insertion operation of the paper feed tray, and feeds the back end of the bent member in the paper feed tray insertion direction. It has a bottom plate elevating mechanism consisting of a stopper means for pressing the tray in the forward direction and a paper tray lock mechanism for fixing the paper tray at a predetermined position, so that the paper can be fed without using electrical parts and associated control units. The bottom plate in the tray can be raised and lowered.

According to the second aspect of the present invention, the bending member is formed such that the bending portion abuts on the bottom plate within the length of the paper feeding roller in the paper feeding tray insertion direction. Can be prevented from being skewed due to the bias of pressurization.

According to the third aspect of the present invention, since the bending portion of the bending member is provided with the member for reducing the resistance when the bottom plate is moved up and down, the frictional resistance between the bottom plate and the bending member is reduced, and the operator has no problem. The operating force can be reduced.

According to the fourth aspect of the present invention, the stopping means pushes out the paper feed tray in the pulling-out direction when the tray lock mechanism is released. Can be withdrawn.

According to the fifth aspect of the present invention, the fixing plate has a fixed fulcrum end which exerts a pushing force near the center of the lower surface of the bottom plate, extends in the sheet feeding tray insertion direction, and rises with the insertion operation of the sheet feeding tray. A bottom plate elevating mechanism comprising a push-up member, stop means for pressing the other end of the push-up member in the front of the paper feed tray, and a paper feed tray lock mechanism for fixing the paper feed tray at a predetermined position is provided. Pressure can be applied at the same position, the bottom plate is not twisted, and stable paper feeding can be performed.

According to the sixth aspect of the present invention, a plurality of push-up members are provided, and the fulcrums of the push-up members on the bottom plate are provided in parallel in the sheet feeding tray insertion direction, and the combined push-up force is lower than the bottom plate. Since it comes near the side center, there is no twist of the bottom plate, and more stable paper feeding can be performed.

According to the seventh aspect of the present invention, the paper feed tray extends in the paper feed tray insertion direction below the bottom plate and has a fulcrum at the front end in the paper feed tray insertion direction, and is bent with the paper feed tray insertion operation. And a bottom plate raising / lowering mechanism including a sheet feeding tray lock mechanism for fixing the sheet feeding tray at a predetermined position. Thus, it is possible to provide a bottom plate elevating mechanism having a small number of parts and a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a sheet feeding device provided with a bottom plate elevating mechanism according to the present invention.

FIG. 2 is a schematic side view of a sheet feeding device corresponding to FIG.

FIG. 3 is a partial schematic side view showing a state of contacting a bottom plate of a bottom plate elevating mechanism of the sheet feeding device corresponding to FIG. 1;

FIG. 4 is a schematic side view of the sheet feeding device corresponding to FIG.

FIG. 5 is a schematic side view of a sheet feeding device including a bottom plate elevating mechanism having another configuration.

FIG. 6 is a schematic side view of a sheet feeding device provided with an improved type of the bottom plate elevating mechanism of FIG. 5;

FIG. 7 is a schematic side view of a sheet feeding device provided with a bottom plate elevating mechanism having another configuration.

FIG. 8 is a schematic side view of a sheet feeding device including a conventionally known bottom plate elevating mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper feed tray 3 Pressure spring 4 Refraction member 7 Bottom plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-323124 (JP, A) JP-A-4-333434 (JP, A) JP-A-62-296230 (JP, A) JP-A-3,962 115023 (JP, A) JP-A-2-233422 (JP, A) JP-A-63-4930 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 1/00-3 / 68

Claims (7)

(57) [Claims] An image forming apparatus includes: a sheet feeding tray inserted into an image forming apparatus in a direction perpendicular to a sheet conveying direction; and a bottom plate disposed in the sheet feeding tray. Paper feed roller and the stacking transfer paper
In a paper feeder for transporting transfer paper, a paper feeder having a fulcrum at a portion extending in a paper feed tray insertion direction below the bottom plate and near the paper feed tray insertion direction and corresponding to a position of the paper feed roller is provided. A bending member that pushes up the bottom plate by bending caused by the insertion operation of the paper tray, and a stopping unit that presses the inner end of the bending member in the paper feed tray insertion direction toward the paper tray,
A sheet feeding device comprising a bottom plate elevating mechanism comprising a sheet feeding tray lock mechanism for fixing a sheet feeding tray at a predetermined position. 2. The feeding device according to claim 1, wherein the bending member is formed such that a bent portion thereof abuts on a bottom plate within a length of a feeding roller in a feeding tray insertion direction. Paper equipment. 3. The sheet feeding device according to claim 1, wherein a member that reduces resistance when the bottom plate is moved up and down is provided in the bending portion of the bending member. 4. The paper feeder according to claim 1, wherein the stopper pushes out the paper feed tray in a pull-out direction when the tray lock mechanism is released. 5. An image forming apparatus comprising: a sheet feeding tray inserted into the image forming apparatus in a direction perpendicular to a sheet conveying direction; and a bottom plate disposed in the sheet feeding tray. Paper feed roller and the stacking transfer paper
And a push-up member having a fixed fulcrum end for applying a push-up force near the center of the lower surface of the bottom plate, extending in the sheet feed tray insertion direction, and rising with the sheet feed tray insertion operation. A sheet feeding device, comprising: a stopper means for pressing the other end of the push-up member in the forward direction of the sheet feeding tray; and a sheet feeding tray lock mechanism for fixing the sheet feeding tray at a predetermined position. . 6. A push-up member comprising a plurality of push-up members, wherein fulcrums of the push-up members on the bottom plate are provided in parallel in the sheet feeding tray insertion direction, and the combined push-up force comes near the center of the bottom plate lower surface side. The paper feeding device according to claim 5, wherein 7. A sheet feeding tray which is inserted into the image forming apparatus in a direction perpendicular to a sheet conveying direction, and a bottom plate disposed in the sheet feeding tray. Paper feed roller and the stacking transfer paper
In the paper feeding device for transporting the transfer paper, an elastic bending which extends in the paper feeding tray insertion direction below the bottom plate, has a fulcrum at a front end on the near side in the paper feeding tray insertion direction, and bends with the insertion operation of the paper feeding tray. A bottom plate elevating mechanism including a member, a stop member that abuts on the other end of the elastic bending member during the sheet tray insertion operation, and a sheet tray lock mechanism that fixes the sheet tray at a predetermined position. Paper feeder.