JPH09255169A - Paper feeder - Google Patents

Abstract

(57) [Abstract] [Problem] It is possible to mount a paper feed tray with a light operating force equivalent to that of a conventional one, and push-in operation with a large acceleration (pushing force) that causes mechanical failure. A sheet feeding device that does not impair the operability and can also guarantee the quality is provided by applying the break only when the sheet feeding is performed. A paper feed tray 2 stored in a main body of the apparatus
In an image forming apparatus of the front loading type that can be pulled out in the front direction of the operation of the main body of the apparatus, only when the paper feeding tray is set in the main body of the apparatus with a certain acceleration or more, the break is applied to the paper feeding tray. Brake mechanism 20 that operates in such a manner that the brake mechanism 22 is supported by an image forming apparatus so as to be horizontally rotatable.
A high friction member 24 fixed to an R-shaped press contact portion provided on a brake lever portion in contact with the side surface of the paper feed tray;
And a spring 26 for urging the high friction member of the brake lever to press the side surface of the paper feed tray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a sheet feeding device used in a copying machine, a printer, a facsimile machine, or a multi-functional machine having these functions, and more particularly, to set a sheet feeding tray in the main body of the apparatus. The present invention relates to a sheet feeding device that can solve various problems when the pushing force at this time is excessive.

[0002]

2. Description of the Related Art In a front-loading type image forming apparatus, a sheet feeding tray constituting a sheet feeding section of the image forming apparatus is constructed so that it can be drawn in and out from the front of the apparatus body. When the paper is set and then pushed into the main body of the apparatus to set the paper, conventionally, a guide rail, an acureide, etc. are provided in order to reduce the operation force of the user. Therefore, the paper feed tray can be smoothly set with a light force. Further, the paper feed tray is configured such that the rear end thereof is abutted against a positioning member inside the apparatus body in order to position the apparatus with respect to the apparatus body. FIGS. 3 (a) and 3 (b) are a perspective view of a conventional paper feed tray in a pulled-out state and a view showing a side fence moving mechanism. As shown in FIG. The fed paper tray 2 has side fences 3 and 4 on the front side and the back side, respectively.
4 is configured to move back and forth in the width direction by a moving mechanism 5 composed of a rack and pinion shown in (b).
The position of each side fence is fixed by mounting the size fixing lock claw 6 shown in (a). by the way,
In the image forming apparatus with such a configuration, when the paper feed cassette is pushed in with a strong force at the time of setting, even if the paper feed tray itself stops at a fixed position inside the apparatus body, The stack of paper sheets tries to move further due to inertial force. In the case of a bundle of 500 sheets (usually 1 pack), this inertial force becomes a force of 20 G or more when set vigorously. This force is applied to the side fence 4 on the back side and the rack and pinion 5 connected to the side fence 4, and overcomes the locking force of the size-fixing lock claw 6 to cause the side fence 3 and
4 or at worst, cracking of the rack or pinion occurs. Further, if the side fences are widened, skew, lateral registration shift, and jam at the time of paper feeding are induced.

As means for preventing these problems,
A mechanism for automatically loading and unloading the paper feed tray by a driving means such as a motor by an auto-reading type in which the paper feed tray is automatically attached and detached by button operation etc. without depending on human setting operation. A mechanism for adding a brake to prevent the paper cassette from entering the main body of the device might be considered.
It will also become large. Further, in the case of, the operating force at the time of each setting becomes heavy, and the operability deteriorates. The present invention has been made in view of the above, and it is possible to mount the paper feed tray with a light operating force equivalent to the conventional one, and to have a large acceleration (a force of pushing force) enough to cause mechanical failure. It is an object of the present invention to provide a sheet feeding device which can guarantee quality without impairing operability by applying a break only when the pushing operation is performed in (4).

[0004]

In order to achieve the above-mentioned object, the invention of claim 1 is a front loading type in which a paper feed tray housed in the main body of the apparatus can be pulled out in the operation front direction of the main body of the apparatus. The image forming apparatus includes a braking mechanism that operates so that the sheet feeding tray is braked only when the sheet feeding tray is set in the main body of the apparatus with an acceleration of a certain value or more. By a brake lever rotatably supported in the horizontal direction, and an R provided on the brake lever portion in contact with the side surface of the paper feed tray.
It has a high friction member fixed to the pressure contact portion of the shape, and a spring for urging the high friction member of the brake lever to press the side surface of the paper feed tray. The invention according to claim 2 is characterized in that, in the braking mechanism, the acceleration at which the brake is applied to the paper feed tray is 20 G or more. According to a third aspect of the present invention, the braking mechanism is activated only when the paper feed tray is set in the main body of the apparatus, and the brake is operated.
The feature is that when the paper feed tray is pulled out, the brake is not applied regardless of the acceleration.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 shows an example of a paper feeding device of a copying machine in which the present invention can be mounted. FIG. 1 shows a sheet feeding device according to an embodiment of the present invention. The sheet feeding device is an image forming apparatus main body 1
It is provided at the lower part. In this example, the upper paper feed tray 10 is a double-sided tray, and the lower paper feed tray 2 is a normal paper feed tray. Both paper feed trays 2 and 10 are supported by an accuride rail 11 provided on the apparatus main body side 1 and the paper feed tray side so as to be able to move forward and backward in the drawing. Reference numeral 12 is a bottom plate on which sheets are stacked, 13 is a sheet feeding roller, and 14 is a pair of registration rollers for feeding the transfer sheet to an image forming section (not shown) of an electrophotographic process. The paper tray 2 has Acculide rail 1 on both side walls.
It is supported by 1 so that it can move forward and backward, and is detachable from the apparatus main body 1. The acculide rail 11 slidably supports the paper feed tray by engaging an inner rail on the paper feed tray side with an outer rail on the apparatus main body side. The transfer paper in the paper feed tray 2 is positioned by the side fences 3 and 4 as shown in FIG.
By moving the size-fixing lock claws 6 and interlocking the rack and pinion shown in FIG. 3 (b), the distance between both side fences can be changed.

FIG. 2 is a perspective view showing the structure of the essential part of the present invention. As shown in FIG. 2, the position corresponding to the upper part of the accuride rail (inner rail) 11a on the side wall of the paper feed tray is shown in FIG. A braking mechanism 20 is arranged. This braking mechanism 20
Is a body fixing bracket 21 fixed to the apparatus body 1 side.
And a brake lever 22 supported rotatably in a horizontal direction by a shaft 21b vertically projecting on a horizontal piece 21a of the fixed bracket 21, and an R-shaped portion of a pressure contact portion 23 provided at an end of the brake lever 22. High friction member 24 formed by coating
And one end of which is fixed to the arm 25 of the brake lever 22 and the other end of which is fixed to the protrusion 21c of the fixed bracket 21 to press the brake lever 22 in the counterclockwise direction (pressing direction). And a spring 26. The pressure spring 26 presses the break lever 22 around the shaft 21b at a constant pressure against the side wall of the paper feed tray. A high-friction member 24 is integrally attached to the contact portion between the side wall and the brake lever 22. Shaft 21
b is disposed on the inner side of the position of the high friction member 24 of the breaker lever, and the breaker lever 22 is difficult to insert into the side wall of the paper feed tray when the paper feed tray is set, and rotates counterclockwise when pulled out. And then run away.
As a result, when the paper feed tray is set at the normal speed, the high friction member 24 slightly slips into the side surface of the paper feed tray, but is set while slipping due to the balance between the friction coefficient of the paper feed tray side wall and the high friction member. To be done.

On the other hand, when the paper feed tray is pushed in at an acceleration of, for example, 20 G or more, the high friction member 24 of the brake lever 22 is pushed into the side of the paper feed tray due to the influence of the acceleration and the paper feed tray is moved. To prevent it from being set inside the main body with its acceleration. That is, the paper feed tray is gently pushed in while being decelerated. The degree of acceleration at which the brake is applied can be variously changed by adjusting the value of the friction resistance of the high friction member and the elastic force of the spring 26. When pulling out the paper feed tray, the brake lever 22 rotates counterclockwise against the spring 26 and is free to escape, so the operability does not change from the conventional one. In other words, it can be pulled out smoothly with a light force.

[0008]

As described above, according to the present invention, in the front loading type image forming apparatus capable of pulling out the paper feed tray housed in the apparatus main body toward the operation front side of the apparatus main body. Only when the paper tray is set in the main body of the device with a certain acceleration or more (for example, 20 G or more),
The sheet feed tray is provided with a braking mechanism that operates so as to be braked, and the braking mechanism is a brake lever rotatably supported in the horizontal direction by the image forming apparatus, and a brake lever contacting the side surface of the sheet feed tray. Since the high friction member fixed to the R-shaped pressure contact portion provided in the portion and the spring for urging the high friction member of the brake lever to press the side surface of the sheet feed tray are pressed, the high friction member is set with a large acceleration. Only in this case, the paper tray will be braked, the impact force applied to the back side fence can be prevented, and the paper can be set in the correct position at all times, resulting in abnormal quality (skew, defective lateral registration, jamming, etc.). ) Can be prevented. Also,
The braking mechanism operates and the brake is applied only when the paper feed tray is set in the main body of the apparatus, and the brake is not applied when the paper feed tray is pulled out regardless of the acceleration. And in the withdrawal operation,
Since the brake does not move, there is no loss of operability.
Further, the brake member used in the braking mechanism does not need a space, and the number of parts is small, so that it is inexpensive.

[Brief description of drawings]

FIG. 1 is a partial configuration diagram of an image forming apparatus using a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a main part of a braking mechanism of the present invention.

FIGS. 3A and 3B are explanatory diagrams of a conventional example.

[Explanation of symbols]

1 image forming apparatus main body, 2 paper feed trays, 3 and 4 side guides, 5 moving mechanism, 11 acryl rails,
12 bottom plate, 13 paper feed rollers, 14 registration roller pair, 20 braking mechanism, 21 bracket, 21a horizontal piece, 21b shaft, 22 brake lever, 23 pressure contact part, 24 high friction member, 25 arm,

Claims (3)

[Claims] 1. A paper feed tray housed in the main body of the apparatus,
Operation of the main body In a front-loading type image forming apparatus that can be pulled out in the front direction, only when the paper feed tray is set in the main body of the apparatus with a certain acceleration or more, the paper feed tray is subject to a break. The brake mechanism includes an operating brake mechanism. The brake mechanism includes a brake lever rotatably supported in the horizontal direction by the image forming apparatus and an R-shaped pressure contact portion provided on the brake lever portion in contact with the side surface of the paper feed tray. A sheet feeding device comprising: a fixed high friction member; and a spring that biases the high friction member of the brake lever so as to press the side surface of the sheet feed tray. 2. The sheet feeding device according to claim 1, wherein in the braking mechanism, an acceleration that applies the brake to the sheet feeding tray is 20 G or more. 3. The braking mechanism operates and the brake is applied only when the paper feed tray is set in the apparatus main body,
3. The sheet feeding device according to claim 1, wherein when the sheet feeding tray is pulled out, no brake is applied regardless of the acceleration.