JPH06191661A - Paper feeding in image forming device - Google Patents

Abstract

PURPOSE:To provide a paper feeding device in an image forming device, which can be easily controlled for each sheet to abut against a feed roller under specific pressure, moreover is simple in constitution and is inexpensive. CONSTITUTION:Since a pin 11 is positioned at the right side of a feed roller rocking body 13 with respect to its center of gravity 14, the feed roller locking body 13 is energized by gravity to be rotated counterclockwise around the pin 11 at all times. Torque thus produced as mentioned above permits the feed roller rocking body 13 to keep a feed roller 7 at the uppermost sheet of the bundle of sheets, and also permits the specficed feed pressure of the feed roller 7 against the bundle of sheets to be built up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a paper feed roller which comes into contact with the uppermost paper of a stack of stacked papers at a predetermined paper feed pressure.
The present invention relates to a sheet feeding device in an image forming apparatus such as a page printer, a facsimile, and a copying machine.

[0002]

2. Description of the Related Art A sheet feeding device of the above type is well known, and in this type of sheet feeding device, the contact between the sheet and the sheet feeding roller is set to a predetermined sheet feeding pressure so as to prevent frequent feeding failure and double feeding. The range is set so that In this case, the sheet feeding device is configured to raise or lower the sheet with respect to the fixed sheet feeding roller to obtain a predetermined sheet feeding pressure, or raise the sheet feeding roller with respect to the fixed sheet. Alternatively, it is known that the paper feeding pressure is lowered to obtain a predetermined paper feeding pressure.

[0003]

However, whichever method is used, it is difficult or costly to control the contact between the paper and the paper feed roller so as to maintain a predetermined paper feed pressure. For example, it is relatively easy to obtain the above-mentioned predetermined paper feed pressure with a paper feed roller whose position is fixed by a bottom plate raising mechanism using a drive source, but the cost increases. Further, it is inexpensive to use one of the paper and the paper feed roller in contact with the other by the spring force, but it is difficult to control the paper feed pressure to a predetermined value because the spring force fluctuates over time. There was a problem.

In view of the above-mentioned conventional problems, the present invention provides an image forming apparatus which is easy to manage so that the contact between the sheet and the sheet feeding roller is at a predetermined sheet feeding pressure, and has a simple structure and is inexpensive. The purpose is to provide a paper feeding device.

[0005]

In order to achieve the above object, the present invention provides a paper feed in an image forming apparatus including a paper feed roller that comes into contact with the uppermost paper of a stack of stacked sheets at a predetermined paper feed pressure. In the apparatus, the paper feed roller is fixed to one end side of the roller shaft, and a drive motor for rotationally driving the paper feed roller is attached to the other end side of the roller shaft. The paper feed roller, the roller shaft, and the drive motor. Is configured as a paper feed roller oscillating body mounted on the main body of the image forming apparatus so as to be capable of oscillating around a fulcrum orthogonal to the axis of the roller shaft, and the oscillating fulcrum of the paper feed roller oscillating body is the aforesaid self-weight. It is characterized in that the paper feed roller is provided at a position where a rotational force in a direction of abutting the uppermost paper of the paper stack from above is applied.

Further, in order to achieve the above object, the present invention is such that the paper feed roller is fixed to one end side of a roller shaft, and a drive motor for rotationally driving the paper feed roller is provided to the other end side of the roller shaft. The paper feed roller, the roller shaft, and the drive motor are attached to the image forming apparatus main body so as to be rockable around a fulcrum orthogonal to the axis of the roller shaft. The rocking fulcrum of the paper feed roller rocking body is provided at a position where a rotational force in a direction in which the paper feed roller abuts the bottom sheet of the sheet bundle from below is urged by its own weight. It is characterized in that a paper pressing member is provided at a position facing the paper roller via the paper bundle.

Further, in order to achieve the above object, the present invention is characterized in that the paper feed roller is formed in an annular shape.

Further, in order to achieve the above object, the present invention is such that at least one of the fixed position of the paper feed roller and the position of the swing fulcrum can be adjusted and moved in the axial direction of the roller shaft. Is characterized by.

Further, in order to achieve the above object, the present invention is characterized in that the swing amount of the paper feed roller rocking body is regulated by a stopper that determines a final position in the rotation direction due to the weight of the paper feed roller. There is.

[0010]

According to the above construction, the swinging fulcrum of the sheet feeding roller swinging member is provided at a position where the rotational force in the direction in which the sheet feeding roller comes into contact with the uppermost sheet of the sheet bundle from above is urged by its own weight. Since the sheet feeding pressure between the sheet and the sheet feeding roller can be obtained by utilizing gravity, a predetermined sheet feeding pressure can be stably obtained over time, and the configuration is simple and inexpensive.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are a front explanatory view and a side explanatory view of an image forming apparatus provided with a sheet feeding device according to the present invention. 1 and 2, reference numeral 1 is a main body of a laser printer as an image forming apparatus, and a paper feeder 2 is arranged above the printer main body 1. As shown in FIG. 1, an image forming unit 3 is arranged below the paper feeding device 2, and the paper fed from the paper feeding device 2 is inverted downward as shown by an arrow before the image forming unit 3 is turned upside down. The toner image is transferred at 3 and is discharged out of the apparatus through the fixing device 4. Reference numeral 5 is an upper cover provided on the printer body 1 so as to be openable and closable.

As shown in FIG. 3, the sheet feeding device 2 has a placing table 6 for placing a bundle of sheets P and a sheet feeding roller 7 for sending out the sheets. The paper feed roller 7 is provided on the printer body 1 side and on the upper cover 5 side. As shown in FIG. 4, the paper feed roller 7 is fixed to one end of a roller shaft 8 with a screw 9, and a drive motor 10 for rotating the paper feed roller 7 is attached to the other end of the roller shaft 8. Has been. The drive motor 10 has
As shown in FIG. 6, pins 11, which are swing fulcrums, are planted on both left and right sides of the housing, and stoppers 12 are provided on the upper part thereof. The left and right pins 11 are provided so that their axes coincide with each other and are orthogonal to the axis L in the plane of the axis L of the roller shaft 8. Note that FIG.
Reference numeral 6a denotes a side fence.

The paper feed roller 7, the roller shaft 8 and the drive motor 10 are constructed as a paper feed roller rocking body 13, and are mounted on the upper cover 5 so as to be rockable around the pin 11. In the present embodiment, the center of gravity 1 of the paper feed roller rocking body 13
4 is set so that the position of the pin 11 is located on the right side of FIGS. 3 and 4.

Further, the paper feed roller 7 is shown in FIG.
As shown in (b) and (c), it is formed in a toroidal shape, that is, a donut shape, and in this example, the sphere is an axis L of the roller shaft 8.
It is formed in a shape in which both sides orthogonal to are cut out by a plane.

As shown in FIGS. 3 and 4, the sheet feeding device 2 having the above structure has the pin 11 located on the right side with respect to the center of gravity 14 of the sheet feeding roller oscillating body 13. A turning force of the pin 13 is always urged counterclockwise about the pin 11 by gravity. With this turning power,
The paper feed roller rocking body 13 is held at a position where the paper feed roller 7 is in contact with the uppermost sheet of the sheet bundle, and the paper feed roller 7
A predetermined feeding pressure for the sheet bundle can be obtained. Then, when the drive motor 10 rotates, the paper feeding roller 7 moves to the roller shaft 8
The sheet is sequentially driven from the topmost sheet of the sheet bundle through the.

Thus, the sheet feeding device 2 obtains the sheet feeding pressure for the sheet bundle of the sheet feeding roller 7 by utilizing the gravity of the sheet feeding roller rocking body 13, so that the sheet feeding pressure is stable over time. Obtained.

By the way, it is preferable that the sheet feeding pressure of the sheet feeding roller 7 with respect to the sheet bundle is set in the range of 200 to 600 gf. Therefore, it is advantageous to be able to adjust the paper feed pressure appropriately. Therefore, as shown by the chain line in FIG. 4, the feeding pressure can be adjusted by changing the fixing position of the feeding roller 7 with respect to the roller shaft 6.

As another method, as shown in FIGS. 7 and 8, the drive motor 10 is fixed to the bracket 15 in which the pin 11 is planted, in which case the roller axial direction formed in the bracket 15 is fixed. The bracket 15 is fixed to the drive motor 10 with the fixing screw 17 through the elongated hole 16 extending in the direction. In this case, by loosening the fixing screw 17, the drive motor 10 for the bracket 15 can be adjusted and moved in the roller axial direction by the lengthwise direction of the elongated hole 16. Then, as shown in FIG. 9, if the position of the center of gravity of the paper feed roller rocking body 13 is brought closer to the pin 11, the paper feed pressure of the paper feed roller 7 becomes lower, and if it gets farther, the paper feed pressure of the paper feed roller 7 becomes smaller. The feed pressure can be adjusted to be higher.

Further, in the above-mentioned paper feeding device, as the number of fed paper sheets advances, the number of remaining paper bundles decreases and the height of the paper feeding roller 7 changes, but the paper feeding roller 7 is a donut as shown in FIG. Since it is formed in a sheet shape, the paper feed roller 7 can be brought into contact with the uppermost paper sheet under almost the same conditions regardless of the number of remaining paper sheets. Therefore, good paper feeding can be obtained regardless of the number of remaining sheets.

Further, when the paper on the paper tray 6 is used up and the paper is to be replenished, the upper cover 5 is opened and replenished as shown in FIG. At this time, the paper feed roller 7 attached to the upper cover 5 is regulated by the stopper 12 hitting the upper cover 5, and is lifted upward together with the upper cover 5. Therefore, there is no possibility that the sheet feeding roller 7 stays at the sheet feeding position and interferes with sheet replenishment. As shown in FIG. 3, the stopper 12 is arranged so that the paper feed roller 7 does not hit the upper cover 5 when feeding the bottom paper.

FIG. 10 is an explanatory view showing another embodiment of the present invention. In this embodiment, the lowermost sheet of the sheet bundle is sequentially fed. In this case, the mounting table 6 is provided with an opening 6b for allowing the paper feed roller 7 to come into contact with the lowermost paper, and the paper pressing member 1 is provided at a position opposed to the paper feed roller 7 via the paper stack.
8 are provided. The paper feed roller rocking body 13 of this example is
The pin 11, which is a fulcrum, is located to the right of the center of gravity 12 in FIG. Therefore, the paper feed roller 7 is constantly urged by gravity to rotate in the direction of coming into contact with the bottom sheet of the sheet bundle. Further, the paper pressing member 18 is attached to the upper cover 5 in FIG. 11, and is rotated upward together with the upper cover 5 at the time of paper supply.

Even in the paper feeding device which feeds from the lowermost paper of the bundle of papers thus constructed, the paper feeding roller 7 can be brought into contact with the paper at a predetermined paper feeding pressure by utilizing gravity, and the paper retainer can be pressed. Since the member 18 is provided, the last uppermost sheet can be fed without any trouble.

[0023]

According to the first aspect of the invention, the swinging fulcrum of the sheet feeding roller swinging body is urged by its own weight to exert a rotational force in a direction in which the sheet feeding roller abuts against the uppermost sheet of the sheet bundle from above. Since it is provided at the position, gravity is used to obtain a predetermined feeding pressure, so that a stable feeding pressure can be obtained over time, and the configuration is simple and inexpensive.

According to the structure of claim 2, the rocking fulcrum of the paper feed roller rocking body is a position where a rotational force is applied by its own weight in a direction in which the paper feed roller abuts the bottom sheet of the sheet bundle from below. Since it uses the gravity force to obtain the specified paper feed pressure, a stable paper feed pressure can be obtained over time. Paper can be fed without any problems.

According to the third aspect of the present invention, since the paper feed roller is formed in a ring shape, the paper can be fed by the paper feed roller under substantially the same condition regardless of the remaining amount of the paper stack. Can abut.

According to the structure of claim 4, at least one of the fixed position of the paper feed roller and the position of the swing fulcrum can be adjusted and moved in the axial direction of the roller shaft.
The feeding pressure can be easily adjusted.

According to the fifth aspect of the present invention, since the swing amount is regulated by the stopper that determines the final position in the rotation direction due to the weight of the sheet feeding roller, the sheet feeding roller is in the free state and the sheet replenishment is also performed. It can be prevented from getting in the way.

[Brief description of drawings]

FIG. 1 is a front explanatory view of an image forming apparatus including a sheet feeding device according to the present invention.

FIG. 2 is an explanatory side view thereof.

FIG. 3 is a detailed explanatory diagram of a sheet feeding device according to the present invention.

FIG. 4 is a front view of a paper feed roller rocking body.

5A, 5B, and 5C are side views of a paper feed roller,
It is a cross section and a perspective view.

FIG. 6 is a perspective view of a drive motor.

FIG. 7 is a perspective view of another example of a drive motor.

FIG. 8 is a side view thereof.

FIG. 9 is an explanatory diagram when adjusting the sheet feeding pressure.

FIG. 10 is a detailed explanatory diagram of another embodiment of the paper feeding device according to the present invention.

11 is an explanatory view showing the movement of the paper pressing member of FIG.

[Explanation of symbols]

 1 Printer Main Body 2 Paper Feeding Device 7 Paper Feeding Roller 8 Roller Shaft 10 Drive Motor 11 Pin 12 Stopper 13 Paper Feeding Roller Oscillator P Paper L Roller Axis

Claims (5)

[Claims] 1. A paper feeding device in an image forming apparatus comprising a paper feeding roller that comes into contact with the uppermost paper of a stack of stacked papers at a predetermined paper feeding pressure, wherein the paper feeding roller is fixed to one end side of a roller shaft. A drive motor for rotationally driving the paper feed roller is attached to the other end of the roller shaft, and the paper feed roller, the roller shaft, and the drive motor are configured as a paper feed roller oscillating body. The rocking member is mounted so as to be rockable around a fulcrum orthogonal to the axis of the roller shaft so that the paper feeding roller is rocked in the direction toward and away from the sheet bundle, and the rocking of the paper feeding roller rocking member The sheet feeding device, wherein the dynamic fulcrum is provided at a position where a rotational force in a direction in which the sheet feeding roller comes into contact with the uppermost sheet of the sheet bundle from above is urged by its own weight. 2. A sheet feeding device in an image forming apparatus, comprising: a sheet feeding roller that comes into contact with a bottom sheet of a stack of stacked sheets at a prescribed sheet feeding pressure, wherein the sheet feeding roller is provided on one end side of a roller shaft. A drive motor for rotating and driving the paper feed roller is fixed to the other end of the roller shaft, and the paper feed roller, the roller shaft, and the drive motor are configured as a paper feed roller oscillating body. The roller rocker is mounted so as to be rockable around a fulcrum orthogonal to the axis of the roller shaft so that the paper feed roller is rocked in the direction of moving toward and away from the sheet bundle, and The swinging fulcrum is provided at a position where the rotational force in the direction in which the paper feed roller abuts against the uppermost paper of the paper stack from above is urged by its own weight, and via the paper feed roller and the paper stack. Paper pressing member is provided at the opposite position Sheet feeding apparatus according to claim Toto. 3. The sheet feeding device in the image forming apparatus according to claim 1, wherein the sheet feeding roller is formed in a ring shape. 4. The sheet feeding device in the image forming apparatus according to claim 1, wherein at least one of a fixed position of the sheet feeding roller and a position of the swing fulcrum is in an axial direction of the roller shaft. A paper feeding device characterized by being adjustable and movable. 5. The amount of rocking of the paper feed roller rocking body is regulated by a stopper that determines a final position in the rotation direction due to the weight of the paper feed roller.
A sheet feeding device in the image forming apparatus according to any one of items 1 to 4.