JPH06271099A - Paper feeder - Google Patents

Abstract

PURPOSE:To set a paper sheet on a specific position so as to be fed without using any complicate mechanism. CONSTITUTION:A paper feeder is provided with a paper feed casette 44 for storing paper sheets P in their piled state, a tray 45 for placing the paper sheets P arranged in this paper feed casette 44, a pick up roller 21 which can draw out the paper sheet P after coming in contact with the paper sheet P staying on the most upper position of the piled paper sheet placed on this tray 45 and also can make displacement while maintaining the contact state with the paper sheet P and a spring material 46 which can energige the tray 45 and regulate, within a specific range, the displacement amount of the paper sheet P staying on the most upper position and making displacement in accordance with the drawing out of the piled paper sheet.

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 provided in, for example, an electrophotographic apparatus.

[0002]

2. Description of the Related Art In this type of sheet feeding device, there is one in which a tray is provided at the inner bottom portion of a sheet feeding cassette and about 500 sheets are placed and stored on this tray.

As the above-mentioned tray is fed with paper and decreases, it is gradually lifted by a dedicated elevator mechanism, and the uppermost paper is always set at a fixed position and taken out by a pickup roller.

That is, when the sheet feeding operation is started, the elevator motor is rotated and the elevator arm is raised via the gear of the elevator drive system. The elevator arm is located below the tray, which lifts the tray.

A sensor is attached to the pickup roller, the tray is lifted until the uppermost sheet comes into contact with the sensor, and when the sheet comes into contact with the sensor, the rotation of the elevator motor is stopped. .
As a result, the tray is stopped and the paper is set at the paper feed position.

[0006]

However, in the prior art, in order to move the tray up and down, a dedicated elevator drive mechanism and sensor are required, so that the structure is complicated, the cost is high, and the apparatus is large. However, there is a problem that a large space is required for the arrangement. Therefore, it is an object of the present invention to provide a paper feeding device capable of setting the uppermost paper at the paper feeding position with a simple configuration.

[0007]

In order to solve the above-mentioned problems, the present invention solves the above-mentioned problems by accommodating a storage unit for accommodating sheets in a stacked state, a mounting member disposed in the storage unit for mounting the sheets, and the mounting unit. The take-out means that is brought into contact with the uppermost sheet of the laminated sheets placed on the member to take out the sheet, and that is displaced while maintaining the state of contact with the sheet, and energizes the placing member, And a biasing member that regulates the displacement amount of the uppermost sheet within the predetermined range when the stacked sheets are taken out.

Further, a storage portion having a depth of the first distance and storing the sheets in a stacked state, a mounting member provided in the storage portion for mounting the sheets, and an upper portion outside the storage portion. It is located and is displaceable to a depth of a second distance shorter than the first distance in the storage portion, and abuts on the uppermost sheet of the laminated sheets placed on the placing member to load the sheet. When the sheet is not placed on the placing member, the placing member is located at the inner bottom portion of the accommodating portion, and the placing member is the second member.
And a biasing member for biasing the biasing member to be positioned at the depth of the distance.

[0009]

When the paper feeding operation is started, the take-out means is brought into contact with the sheet and the uppermost sheet is taken out. When the paper gradually decreases due to this removal, the take-out means tries to displace in the paper decreasing direction, but at this time, the placing member is urged by the urging force of the urging member, and The displacement amount is regulated within a predetermined range. By this regulation,
The difference between the take-out positions of the uppermost sheet and the lowermost sheet is minimized, and the sheet feeding distance is made constant to prevent variations in sheet feeding time.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 2 shows the internal construction of the electronic copying machine, in which 1 is the main body of the copying machine. A scanner 2 is provided on the upper side of the main body 1 of the copying machine. The scanner 2 includes first and second carriages 5 and 6, and a light source 7 and a first mirror 8 are arranged on the first carriage 5. The second carriage 6 is provided with second and third mirrors 9 and 10.

The light reflected by the third mirror 10 is sent to a photosensitive drum 11 described later via an optical system 31. The optical system 31 includes a lens 32, a fourth, a fifth, and a sixth.
The mirrors 33, 34, and 35 of FIG.

A photosensitive drum 11 is rotatably provided at a substantially central portion of the copying machine main body 1. A charger 12, a developing device 13, a transfer charger 14a, a peeling charger 1 are provided around the photosensitive drum 11 along the rotation direction thereof.
4b, a cleaner 15 and a static eliminator 16 are provided.

Further, in the figure, reference numeral 26 is a conveying path for conveying the paper, and the conveying path 26 is sequentially arranged along the conveying direction of the paper.
Registration roller pair 25, the transfer charger 14a,
A peeling charger 14b, a conveyor belt 27, a fixing roller pair 28, and a paper discharge roller pair 29 are arranged.

A paper feeding device 18, which will be described later, is provided on the lower side of the main body 1 of the copying machine.
Are picked up by a pickup roller 21 as a pick-up means.

The paper P taken out by the pickup rollers 21 ... Is a separation pad 22 and the separation pad 22.
The paper is fed by being separated one by one by the rotation of the paper feed roller 23 that is pressed against the paper. The paper P fed by the rotation of the paper feed roller 23 is conveyed along the conveyance path 24 and is sent to the registration roller pair 25.

Further, a manual paper feeding portion 41 is provided on one side surface of the copying machine body 1, and a paper ejection tray (not shown) for receiving the paper P ejected from the paper ejection roller pair 29 on the other side surface portion. Is provided.

The sheet fed by the manual feed section 41 is fed along the feeding path 71. In the conveyance path 71, a pickup roller 76, an empty switch 72, a feed roller 74, a feed roller 74, are sequentially arranged along the conveyance direction of the manual feed sheet.
Separation pad 7 that rolls under the feed roller 74
7 are provided.

Therefore, at the time of image formation, the first and second carriages 5 and 6 of the scanner 2 are moved and the original set on the original glass table 36 is exposed and scanned by the light from the light source 7. Light reflected from the document is reflected by the first to third mirrors 8
10 to 10, and an image is formed on the photosensitive drum 11 via the optical system 31. The surface of the photosensitive drum 11 is charged by the charger 12, and an electrostatic latent image is formed by the above image formation. This electrostatic latent image is sent to the developing device 13 by the rotation of the photosensitive drum 11, and is developed by supplying a developer there. This developer image is transferred to the paper feed cassette 18 or the paper P supplied from the manual paper feed section 41 by the transfer charger 14
It is transcribed by the action of a. Then, the sheet P on which the image is transferred is peeled from the photosensitive drum 11 by the action of the peeling charger 14b, then is conveyed by the conveying belt 27 and is sent to the fixing roller pair 28, where it is fixed and then fixed. The paper is discharged onto a paper discharge tray (not shown) by the paper discharge roller 29.

When the paper is manually fed, the empty switch 72 is turned on and the pickup roller 76 is rotated and lowered to take out the paper. This paper is sent between the feed roller 74 and the separation pad 77, and is separated and sent out one by one.

As shown in FIGS. 1 and 3, the paper feeding device 18 is provided with a paper feeding cassette 44 as a storage portion, and a tray 45 as a mounting member is provided at the inner bottom of the paper feeding cassette 44. It is provided. 500 sheets of paper P can be placed on the tray 45.

The pickup roller 21 as the above-mentioned take-out means is brought into contact with the upper surface of the sheet P placed on the tray 45. The pickup roller 21 is attached to a rotary arm 51, and the rotary arm 51 is rotated by turning on and off an electromagnetic solenoid 53 to vertically move the pickup roller 21.

That is, when the energization of the electromagnetic solenoid 53 is stopped and demagnetized, the rotating arm 51 is rotated upward to move the pickup roller 21 upward, and the electromagnetic solenoid 53 is energized and excited. Then, the pickup roller 21 is lowered by its own weight so as to come into contact with the uppermost surface of the paper P. On the other hand, a spring member 46 as a biasing member is provided on the lower side of the tray 45, and the spring member 46 pushes the tray 45 upward. In the present embodiment, the strength of the spring member 46 is balanced with the weight of 250 sheets of A4 size paper. When the paper P is A4 size and 250 or more sheets are loaded, the tray 45 is lowered to the lowest point due to the weight of the paper.

However, at the time of paper feeding, the electromagnetic solenoid 5
3 is energized and excited, the rotating arm 51 rotates downward, the pickup roller 21 descends, contacts the uppermost surface of the paper P, and rotates.

By rotating the pickup roller 21, the paper P is taken out and sent between the paper feed roller 23 and the separation pad 22. Here, after the sheets P are separated one by one, they are fed to the registration roller 25 side in the copying machine main body 1 through the transport path 24.

By this paper feeding, the paper P is reduced, and the paper P
When the number of sheets is less than 250 sheets, the tray 45 is lifted by the urging force of the spring 46 every time the number of sheets P decreases, and the position of the uppermost sheet P on the tray 45 remains about 250 sheets. It is no lower than the position.

[0027] Note that if the paper P is A ₅ size, when accommodating 500 sheets of paper P in the paper feed cassette 44, the tray 45 by the weight of the sheet P, and down to the lowest point, the sheet feed At some times, the pickup roller 21 descends to feed the uppermost sheet P into the main body 1.

However, since the weight of the A5 size is half that of the A4 size, the tray 45 is moved by the spring 46 each time the paper P is fed into the copying machine main body 1 and the paper P is reduced from 500 sheets. The position of the uppermost sheet of the tray 45 is lifted and does not lower than the position of the uppermost sheet of paper when storing 500 sheets.

This situation will be described with reference to FIGS. 6 and 7. First, FIG. 6 shows the inside of the paper feed cassette 44 when 500 sheets of A4 size paper P are stored, and FIG. 7 shows half of the paper P (in this example, A5 size) paper P ′ 50.
The inside of the paper feed cassette 44 when 0 sheets are stored is shown.

As described above, in the present embodiment, the strength of the spring member 46 for pushing up the tray 45 corresponds to the weight of 250 A4 size sheets, so that the A4 size sheet P'is fed into the paper feed cassette. When 500 sheets are stored in 44, the tray 45 does not rise until the remaining amount of sheets reaches the weight corresponding to the biasing force of the spring member 46, that is, until the number of sheets P reaches 250, and up to this point. Paper feed is performed by the lowering of the pickup roller 21 (FIG. 6A).
(B)). When the number of sheets of paper P becomes 250 or less, the biasing force of the spring member 46 exceeds the weight of the sheets of paper P this time, so that the tray 4
5 is moved up and the paper P is brought into contact with the pickup roller 21, whereby the paper is fed (FIG. 6C). Since the pickup roller 21 reaches the lowermost position of the movable range when the number of sheets P reaches 250 (FIG. 6B), even if the number of sheets P reaches 250, it does not descend further. It has become. Then, when the paper P is exhausted, the position of the tray 45 pushed up by the spring member 46 and the lower limit position of the pickup roller 21 match (FIG. 6 (d)). Next, a case in which 500 A5 size sheets are stored will be described.

When 500 sheets of A5 size sheets are stored, the weight thereof is equivalent to 250 sheets of A4 size sheets, so the tray 45 is at the lowest position (FIG. 7A). Since the biasing force of the spring member 46 increases as the amount of the paper P ′ decreases, the tray 45 gradually rises.

Further, the pickup roller 21 is gradually lowered (FIG. 7 (b)). Then, when the paper P'is exhausted, as described above, the position of the tray 45 pushed up by the spring member 46 and the lowest limit position of the pickup roller 21 coincide with each other (FIG. 7C). .

As described above, the paper feed cassette 44 of this embodiment
In order to feed all the accommodated papers, the pickup roller 21 may be lowered to the depth of half of the paper feed cassette 44. Even if there are few papers, the pickup roller 21 reaches the bottom of the paper feed cassette 44. Since there is no need to descend, the time required to take out the uppermost sheet and the lowermost sheet does not significantly differ.

[0034]

As described above, according to the present invention, the tray is urged by the urging member, and the displacement amount of the uppermost sheet due to the takeout of the stacked sheets is maintained in the contact state with the ejecting means. Since it is regulated within the range, there is no need for a sensor or control mechanism like the elevator mechanism, and the structure can be simplified.
As a result, the cost can be reduced, the transport length does not fluctuate when the paper is taken out, and the paper can be accurately fed in a constant paper feeding time.

[Brief description of drawings]

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

FIG. 2 is an internal configuration diagram showing an electronic copying machine including the paper feeding device of FIG.

FIG. 3 is a perspective view showing a sheet feeding cassette of the sheet feeding device of FIG.

FIG. 4 is an explanatory diagram showing a case where an A4 size sheet is fed by the sheet feeding device of FIG. 1;

FIG. 5 is an explanatory diagram showing a case where an A5 size sheet is fed by the sheet feeding device of FIG. 1;

FIG. 6 is an explanatory diagram showing the inside of a paper feed cassette when A4 size paper is fed by the paper feed device of FIG. 1;

FIG. 7 is an explanatory diagram showing the inside of the paper feed cassette when A5 size paper is fed by the paper feed device of FIG. 1;

[Explanation of symbols]

P ... Paper, 21 ... Pickup roller (takeout means), 4
4 ... Paper feed cassette (storage unit), 45 ... Tray (placement member), spring material (biasing member).

Claims (3)

[Claims] 1. An accommodating section for accommodating sheets in a stacked state, a placing member provided in the accommodating section for placing the sheet, and an uppermost layer of the laminated sheet placed on the placing member. While taking out the paper by bringing it into contact with the paper, the take-out means that can change the contact position with the paper and the displacement amount of the topmost paper accompanying the take-out of the stacked paper by urging the placing member within the predetermined range A sheet feeding device comprising: 2. The biasing member comprises a spring member, and biases the maximum displacement position of the take-out means at the time of taking out the paper and the position of the placing member when the paper is not placed to be equal. The sheet feeding device according to claim 1, wherein the sheet feeding device is a sheet feeding device. 3. A storage part having a depth of a first distance and storing paper in a stacked state, a mounting member provided in the storage part for mounting the paper, and above the storage part. It is located and is displaceable to a depth of a second distance shorter than the first distance in the storage portion, and abuts on the uppermost sheet of the laminated sheets placed on the placing member to load the sheet. A take-out means for taking out and a biasing member that is located at the inner bottom of the storage portion and that biases the placing member so as to be located at the depth of the second distance when no sheet is placed on the placing member. A sheet feeding device comprising: a member.