JPH06156764A - Paper feeding device - Google Patents

Abstract

PURPOSE:To provide a paper feeding device which prevents the reduction of the combing effect without increasing cost. CONSTITUTION:On the outer periphery of a pick-up roller 19, projection parts 33 having a uniform height over in the lengthwise direction are installed in the nearly equal intervals in plural stages, and the outer periphery of the pick-up roller 19 is formed into an uneven surface. A bottom plate 30 is made of the elastic material. A piled sheet S is placed on the bottom plate 30, and is pushed on the pick-up roller 19 by pushing up the bottom plate 30, and the pick-up roller 18 is revolved to apply vibration to the piled sheet S, and the sheets are driven out successively, and transported one by one, separated by a feeding roller 20 and a retarding roller 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can be applied to a recording apparatus for recording on a sheet by printing, transferring, copying, printing, etc., such as a laser printer, a copying machine and a facsimile. Specifically, in such a recording device, the loading sheet
The present invention relates to a sheet feeding device in which a sheet is pressed against a pickup roller and the pickup roller is rotated to sequentially feed sheets.

[0002]

2. Description of the Related Art Conventionally, in this type of sheet feeding device, a plurality of rollers are fitted on the outer periphery of a card having an elastic hub at intervals so that the axis is in the same direction as the axis of the card. Part of each roller is projected from the outer periphery of the card,
There has been a type in which the card is pressed against a loading sheet and the rollers are pulled inward by the bending of the hub so that the sheets are sequentially fed out and separated. (See JP-A-53-129649)

Further, a rotating body having an elastic piece in the radial direction is made of an elastic material, and the rotating body is rotated to bend the elastic piece and press it against a loading sheet so that the sheet is fed out and separated. There was something I did. (Actual exploitation 61-52651
(See Japanese Patent Laid-Open No. 60-258042)

[0004]

However, a plurality of rolls are required.
The sheet feeding device provided with a card having a ladle has a drawback that the cost of the device is increased because the structure of the card is complicated. In addition, the rotary body having the elastic piece on the outer periphery has a drawback that the elastic piece pressed against the sheet is setted and the carding effect is gradually reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding device in which the carding effect does not decrease without increasing the cost.

[0006]

Therefore, the present invention provides
For example, as in the embodiment shown below, the loading sheet S is pressed against the pickup roller 19 and the pickup roller 19 is pressed.
Paper feeding device 17 that rotates sheet 19 and sequentially feeds sheet S
2 is characterized in that the outer circumference of the pickup roller 19 is formed as an uneven surface.

According to a second aspect of the present invention, the loading sheet S is placed on the bottom plate 30 and the loading sheet S is pushed up by pushing the loading plate S as in the following illustrated embodiment. The sheet feeding device 17 according to claim 1, which is pressed against the pickup roller 19, wherein the bottom plate 30 is made of an elastic material.

According to a third aspect of the present invention, the loading sheet S is attached to the bottom plate 30 as shown in the following embodiments.
2. The mounting sheet S is placed on the upper surface and the bottom plate 30 is pushed up to press the loading sheet S against the pickup roller 19.
In the paper feeding device 17 described in the above 1,
The bottom plate portion 30a corresponding to the pressing position to the la 19
In addition, the elastic member 35 is provided.

[0009]

When the sheet S is delivered, the loading sheet S is pressed against the uneven surface of the pickup roller 19 and the pickup roller 19 is rotated to give vibrations to the loading sheet S. Sheet S is fed out in order.

According to the second aspect of the present invention, when the loading sheet S is pressed against the uneven surface of the pickup roller 19,
The bottom plate 30 bends corresponding to the uneven surface.

Further, according to the third aspect, when the loading sheet S presses against the uneven surface of the pickup roller 19, the elastic member 35 elastically deforms corresponding to the uneven surface.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is an overall schematic configuration diagram showing an internal mechanism of a laser printer including a paper feeding device according to an embodiment of the present invention. Reference numeral 10 in the figure denotes the apparatus main body.
The apparatus main body 10 is provided with a photoconductor 11 substantially in the center thereof, and a charger 12 and an optical writer 13 are sequentially provided around the photoconductor 11.
A developing device 14, a transfer device 15, and a cleaning device 16 are arranged.

Then, as the photoconductor 11 rotates clockwise in the drawing, the surface of the photoconductor 11 is uniformly charged by the charger 12, and then the laser light is irradiated by the optical writer 13 to form an electrostatic latent image. Then, the toner is attached by the developing device 14 to form a visible image.

On the other hand, on the lower front side (lower right side in the figure) of the apparatus main body 10, the sheet feeding device 17 of the present invention is provided. In the sheet feeding device 17, a pickup roller 19, a pair of feeder rollers 20 and a retard roller 21 which are arranged vertically are arranged. Then, the sheet S is delivered from the paper feed cassette 18 which is detachably attached to the apparatus main body 10 by the pickup roller 19, and the feeder roller 20 and the return roller 20.
The sheet is conveyed one by one with the la 21 and abutted against the pair of registration rollers 22 to stop. Thereafter, the registration roller 22 is rotated in synchronization with the rotation of the photoconductor 11 to convey the sheet S, and the transfer device 15 transfers the visible image on the surface of the photoconductor 11 to the sheet S.

Then, the sheet S after the image transfer is fixed to the fixing device 2.
The sheet is conveyed to the sheet 3, and the fixing device 23 fixes the transferred image, and then the sheet is discharged to the sheet discharge unit 25 through the sheet discharge path 24. The surface of the photoconductor 11 after the image transfer is cleaned by the cleaning device 16.

By the way, as shown in FIG. 1, the sheet feeding device 17 includes a bottom plate 3 made of an elastic material in a sheet feeding cassette 18.
0 is provided from the center in the length direction of the paper feed cassette 18 to the front end, and the base end is rotatably attached with a shaft 31 provided at the bottom of the paper feed cassette as a fulcrum. Further, below the paper feed cassette 18, a rotatable arm 32 is provided which is urged clockwise in the drawing by a spring or the like (not shown). From the bottom to the bottom plate 30.

On the other hand, as shown in FIG. 2, the pickup roller 19 is provided with a plurality of protrusions 33 having a uniform height along the length thereof at substantially equal intervals on the outer circumference thereof.
The outer circumference of the la 19 is an uneven surface.

Then, as shown in FIG. 1, the sheet S is loaded on the bottom plate 30, and the bottom plate 30 is pushed up by the arm 32 so that the loaded sheet S is pressed against the pickup roller 19.
Then, the pickup roller 19 is rotated as shown by the arrow to feed the sheet S in order. Then, the uneven surface of the outer periphery presses the loading sheet S with strength and weakness, and the bottom plate 30 flexes periodically correspondingly, so that the loading sheet S vibrates and the sheet S is carded. And the sheet S is easily separated. Then, the sheet S is separated by the feeder roller 20 and the retard roller 21, and is conveyed one by one to the registration roller 22.

In the above embodiment, the pickup roller 1
9 is a plurality of protrusions 33 extending in the lengthwise direction on the outer periphery thereof.
However, as shown in FIG. 3, a plurality of protrusions 34 may be arranged on the entire outer circumference in an appropriate distribution to form the uneven surface. Then, when the loading sheet S hits the pickup roller 19, there is always a certain protrusion 3
4, the vertical movement of the bottom plate is not unnecessarily increased, so that noise when the uneven surface and the pickup roller 19 are in contact can be reduced.

Further, in the above-mentioned embodiment, the bottom plate 30 is made of an elastic material, but the bottom plate 30 is made of a hard material and the bottom plate portion 30 corresponding to the pressing position to the pickup roller 19 is formed.
An elastic member may be provided in a. That is, as shown in FIG. 4, the bottom plate 30 is made of a metal plate, and the pickup roller 19
An elastic member 35 such as a rubber sheet is attached to the bottom plate portion 30a corresponding to the pressing position with respect to the adhesive member by adhesion or the like. Then, when the loading sheet presses against the uneven surface of the pickup roller, the elastic member elastically deforms corresponding to the uneven surface to further enhance the sheet combing effect without vibrating the bottom plate itself. To be able to In addition, the front end of the sheet S is placed on the elastic member 35 and stacked to increase the frictional force between the loading sheet S and the bottom plate 30 to provide a carding effect when the remaining amount of the loading sheet S is reduced. Try to raise it.

[0021]

Therefore, according to the present invention, since the pickup roller has a simple structure in which the outer periphery of the pickup roller is formed as an uneven surface, the cost does not increase. Further, since the outer circumference of the pickup roller is simply an uneven surface, it is possible to provide a sheet feeding device in which the picking roller is not settled and the carding effect is not deteriorated.

According to the second aspect of the present invention, when the loading sheet comes into contact with the uneven surface of the pickup roller, the bottom plate bends corresponding to the uneven surface, so that the pickup roller rotates with the rotation. The bottom plate vibrates, and the combing effect of the sheet can be further enhanced.

According to the third aspect of the invention, when the loading sheet presses against the uneven surface of the pickup roller, the elastic member elastically deforms corresponding to the uneven surface, so that the bottom plate itself is Shake the loading sheet without vibrating
The carding effect of the glove can be further enhanced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the pickup roller.

FIG. 3 is a perspective view showing another example of a pickup roller.

FIG. 4 is a view showing a state in which a sheet is loaded on a bottom plate and pressed against a pickup roller in another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a laser printer including such a sheet feeding device.

[Explanation of symbols]

 17 Paper Feeding Device 18 Paper Feeding Cassette 19 Pickup Roller 30 Bottom Plate 30a Bottom Plate Part 35 Elastic Member S Sheet

Claims (3)

[Claims] 1. In a paper feeding device for pressing a loading sheet against a pickup roller and rotating the pickup roller to sequentially deliver sheets, the outer periphery of the pickup roller is formed into an uneven surface. , Paper feeder. 2. The sheet feeding device according to claim 1, wherein the stacking sheet is placed on a bottom plate, and the bottom plate is pushed up to press the stacking sheet against the pickup roller.
A paper feeding device in which the bottom plate is made of an elastic material. 3. The sheet feeding device according to claim 1, wherein the stacking sheet is placed on a bottom plate, and the bottom plate is pushed up to press the stacking sheet against the pickup roller.
A sheet feeding device, in which an elastic member is provided on the bottom plate portion corresponding to the pressing position on the pickup roller.