JPH05743A - Paper feeding device - Google Patents

Abstract

PURPOSE:To provide a paper sheet feeding device which can vary the pressing force of a pick-up roll according to the thickness of a paper sheet, adjust the variation quantity of the pressing force according to the magnitude of the pressing force and can supply paper sheets having a variety of thickness in stable manner. CONSTITUTION:A pick-up roll 14 is installed on one edge side of a roll supporting body 11. A paper sheet sensor 25 is arranged on the downstream side of a separating roll 19. A weight 22 is shiftable laterally along a screw groove 21a, by the revolution of a motor 20. The drive time of the motor 20 in one time is (t) sec. in the division between a weight detecting sensor 24a and a weight detecting sensor 24b where the pressing force by the pick-up roll 14 reduces, while the time is 2t sec. in the division between the weight sensor 24b and a weight sensor 24c where the pressing force becomes intermediate, and further, the time is 4t sec. in the division between the weight sensor 24c and a weight sensor 24d where the pressing force becomes high.

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 for sequentially feeding the sheets stacked in a sheet container (tray) in a copying machine or the like one by one.

[0002]

2. Description of the Related Art Conventionally, this type of sheet feeding device has been constructed as shown in FIG. 6, for example. In this paper feeding device, a pickup roll 4 which rotates around a rotation shaft 3 is arranged at one end of a roll support 1 which is rotatable around a rotation shaft 2, and a paper sheet is pressed by the own weight of the pickup roll 4. When the sheet 5 is conveyed by a conveying path 6 and the sheet 5 is double-fed, the sheet 5 is separated by a feed roll 7 and a separation roll 8 pressed against the sheet.

By the way, generally, the relationship between the thickness of the sheet 5 and the pressing of the pickup roll 4, the double feeding and the misfeed is as shown in FIG. Therefore, when the paper 5 is fed one by one, it is necessary to divide the pressing force according to the thickness of the paper 5, such as a low pressing force for thin paper and a high pressing force for thick paper.

[0004]

In the above-mentioned conventional paper feeding device, since the pressing force of the pickup roll 4 is constant, the sheet 5 having a thickness suitable for the pressing force can be stably fed. However, if the paper is thinner than that, the pressing force is too high to send out a plurality of papers at a time, and the separation roll 8 cannot separate the papers, resulting in double-feeding. I could not send out the paper,
It becomes a misfeed. As described above, the conventional paper feeding device has a drawback that the usable paper is extremely limited.

Therefore, the same applicant as the present applicant has proposed a paper feeding device for feeding the paper while changing the pressing force of the pickup roll 4 according to the paper thickness. by the way,
In order to feed the paper more stably, it is desirable that the amount of change in the pressing force of the pickup roll 4 per time is large when the pressing force is high and small when the pressing force is low.

However, in the paper feeding device, the amount of change in the pressing force of the pickup roll 4 per time is always constant regardless of whether the pressing force is high or low. Therefore, if the amount of change is adjusted to a place where the pressing force is high, the amount of change is too large at the place where the pressing force is low, and if the amount of change is adjusted to the place where the pressing force is low, it is too small at the place where the pressing force is high. There was a drawback that it was difficult to obtain a sufficient pressing force.

The present invention has been made in view of the above problems, and an object of the present invention is to determine the amount of change in the pressing force by the paper feeding means.
An object of the present invention is to provide a paper feeding device that can change the pressing force according to the magnitude of the pressing force and can stably feed sheets of various thicknesses.

[0008]

A sheet feeding device according to the present invention comprises a sheet storing section for storing a plurality of sheets in a stack.
A sheet feeding means for feeding the sheets accommodated in the sheet accommodating section from the sheet accommodating section in a state of being pressed in order from the uppermost sheet by its own weight, and the pressing force by the sheet feeding section is adjusted according to the thickness of the sheet. The pressing force adjusting means, the paper detecting means arranged downstream of the paper storing portion in the paper feeding direction and detecting the paper sent out from the paper storing portion, and depending on the detection result of the paper detecting means. A pressing force control unit that detects the thickness of the sheet and changes the pressing force by the pressing force adjusting unit to an appropriate value, and a pressing amount of the pressing force change amount by the pressing force control unit. And a pressing force change amount control means for changing the pressing force according to the magnitude of the pressure.

With the above-described structure, in the sheet feeding device of the present invention, the pressing force of the sheet feeding means changes according to the thickness of the sheet, and the amount of change in the pressing force is large at a high pressing force. Also, since it can be made smaller in a place where the pressing force is low,
Stable paper feed can be realized by the optimum pressing force according to the paper thickness.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows the structure of a sheet feeding device according to the first embodiment of the present invention. In the figure, 11 is a roll support 11 which is rotatable around a rotary shaft 12, and a pickup roll 14 which is rotatable around a rotary shaft 13 is provided at one end of the roll support 11. Below the pickup roll 14, a tray 16 containing a large number of sheets 15 is arranged. Pickup roll 1
4 is rotated counterclockwise in the figure by a drive motor (not shown), and its frictional force causes the uppermost sheet 15 on the tray 16
Are sent out in sequence. A feed roll 18 is disposed downstream of the pickup roll 14 in the paper feed direction via a conveyance path 17, and a separation roll 19 for separating the paper 15 from the feed roll 18 when the paper 15 is double-fed. There is. A paper sensor 25 is arranged on the downstream side of the separating roll 19, and the sensor 25 detects the arrival of the paper 15.

A motor 20 for moving a weight is disposed on the upper surface of the roll support 11 on the other end side. This motor 20
The shaft 2 parallel to the upper surface of the roll support 11
1 is connected, and the tip of the shaft 21 is rotatably supported by a bracket 23 provided on the upper surface of the roll support 11. The shaft 21 of the motor 20 is provided with thread grooves 21a at equal intervals, and the weight 2
2 is attached, and the weight 22 is movable left and right along the screw groove 21a as the motor 20 rotates.

On top of the shaft 21, the shaft 2
A plurality of weight detection sensors 24a to 24d, for example, four weight detection sensors 24a to 24d are horizontally arranged along the line 1.
The position of 2 in the horizontal direction is detected. Here, the weight detection sensor 24a as shown in FIG.
L _{1 is} a section between the weight detection sensor 24b and the weight detection sensor 24b, and L is a section between the weight detection sensor 24b and the weight detection sensor 24c.
_2. Let L ₃ be the section between the weight detection sensor 24c and the weight detection sensor 24d.

FIG. 2 shows the configuration of the control unit of the paper feeding apparatus. The paper detection signal output from the paper detection sensor 25 and the weight detection signals output from the weight detection sensors 24a to 24d are respectively stored in the CPU (center). Processing device) 41. The CPU 41 receives the paper detection signal output from the paper detection sensor 25, determines the thickness of the paper 15, and sends a control signal to the motor 20 via the motor drive unit 42 according to the result to determine the thickness of the paper 15. 2 according to the weight
2 is moved to adjust the pressing force of the pickup roll 14. That is, when the paper 15 is thick, the weight 22 is placed on the section L ₃ side so that a high pressing force is obtained,
If 5 is thin, the weight 22
To the section L ₁ side. The paper detection sensor 25
For example, a photo sensor, a minute angle sensor, or the like is used. When the photo sensor is used, the thickness of the paper 15 is calculated from the time from when the paper 15 is sent out by the pickup roll 14 to when it reaches the sensor. When the micro angle sensor is used, the thickness of the paper 15 is calculated by the angle change. The thickness of the paper 15 can be detected.

Further, the CPU 41 is a weight detection sensor 2
The rotation time per rotation of the motor 20 is different for every three sections 4a to 24d. That is, when the weight 20 is in the section L ₁ between the weight detection sensor 24a and the weight detection sensor 24b, the motor 20 is rotated for t seconds, and the weight 20 is moved to the weight detection sensor 24b and the weight detection sensor 24c.
The interval motor 20 when in the L ₂ between the rotated 2t seconds, that the motor 20 rotates 4t seconds when the weight 20 is in the interval L ₃ between the weight detection sensor 24c and the weight sensor 24d and As described above, the change amount of the pressing amount per one time is small in the section L _{1 where the} pressing force is low,
In the section L _{3 where the} pressing force is large, it is increased so that the amount of change in the pressing force suitable for the paper 15 is obtained.

In this paper feeding device, the pick-up roll 14 is rotationally driven by a drive motor (not shown), so that the paper 15 is fed from the tray 16 one by one.
The fed-out sheet 15 moves along the conveyance path 17, passes between the feed roll 18 and the separation roll 19, and is separated one by one when double-fed. When the leading edge of the sheet 15 that has passed through the separation roll 19 reaches the sheet detection sensor 25, the detection signal from the sensor 25 is received and the sheet detection sensor 25 shown in FIG.
The CPU 41 shown in FIG. 3 determines the sheet thickness, and sends a control signal to the motor 20 via the motor drive unit 42 according to the determination result to control the rotation of the motor 20. That is, when the paper 15 is thick, the weight 22 is increased so that the pressing force is increased.
The interval L _3, section when it is normally L _2, also paper 1
When 5 is thin, the weight 22 is moved to the section L ₁ side so that the pressing force becomes low. Then, such movement of the weight 22 is detected by the weight detection sensors 24a to 24d, and when the weight 22 is in the section L ₁ , the motor 20 is moved.
Is rotated for t seconds, the motor 20 is rotated for ₂ t seconds in the section L _2, and the motor 20 is rotated for 4 t seconds in the section L ₃ . As a result, the change amount of the pressing amount per time is small in the section L ₁ where the pressing force is low, is large in the section L _{3 where} the pressing force is large, and is in the middle in the section L ₂ in the middle, whereby the thickness of the sheet 15 is increased. It is possible to obtain the amount of change in pressing force suitable for

In the above embodiment, the motor 20
The amount of change in the pressing amount of each section was changed by changing the rotation time of the motor.
The rotation time may be fixed and the rotation speed may be changed by changing the voltage.

FIG. 4 shows the construction of the main part of a paper feeding device according to another embodiment of the present invention.

In the present embodiment, the distance between the screw grooves 30a formed on the shaft 30 of the motor 20 is adjusted so that the relationship between the rotation time of the motor 20 and the magnitude of the pressing force becomes the curve shown in FIG. It is set so that the side is widened and becomes narrower toward the end on the motor 20 side. Then, a shaft 32 is arranged above the shaft 30 in parallel with the shaft 30, and is supported by brackets 23 and 33 provided on the upper surface of the roll support 11, and a weight 31 is provided along the shaft 32. It is slidable to the left and right, and a guide pin 31a is attached to the lower part of the weight 31 so as to face downward. The guide pin 31a moves along the thread groove 30a with the rotation of the shaft 30, whereby the weight 31
Can be moved left and right.

With the above-described structure, in the paper feeding device of this embodiment, the pressing force is changed and the change is caused by rotating the motor 20 in accordance with the detection signal from the paper detection sensor 25 shown in FIG. The amount automatically increases when the pressing force is high and decreases when the pressing force is low. Therefore, as in the first embodiment, the weight detection sensors 24a ...
It is not necessary to provide 24 da, and it is not necessary to change the rotation time or voltage of the motor 20.

[0021]

As described above, according to the paper feeding device of the present invention, a paper storage unit for stacking and storing a plurality of paper sheets, and the paper stored in the paper storage unit from the uppermost paper due to its own weight. Paper feeding means for feeding the paper from the paper accommodating portion in a state of being pressed in order, pressing force adjusting means for adjusting the pressing force by the paper feeding means according to the thickness of the paper, and the paper feeding direction of the paper accommodating portion. A sheet detecting unit that is arranged on the downstream side and detects the sheet sent out from the sheet storing unit, detects the thickness of the sheet according to the detection result of the sheet detecting unit, and presses it by the pressing force adjusting unit. A pressing force control means for changing the pressure to an appropriate value, and a pressing force change amount control means for changing the amount of change in the pressing force by the pressing force control means per time according to the magnitude of the pressing force. Equipped, the pressing force of the paper feeding means It is configured to change according to the thickness of the paper, and the amount of change in this pressing force is large at places where the pressing force is high and small at places where the pressing force is low. Stable paper feed can be realized by pressing force of.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a paper feeding device according to a first embodiment of the invention.

FIG. 2 is a side view showing a main part of the paper feeding device shown in FIG.

FIG. 3 is a block diagram showing a configuration of a control unit of the paper feeding device of FIG.

FIG. 4 is a side view showing a main configuration of a sheet feeding device according to a second embodiment of the invention.

5 is a diagram showing a relationship between a rotation time of a motor and a pressing force in the paper feeding device of FIG.

FIG. 6 is a side view showing the configuration of a conventional paper feeding device.

FIG. 7 is a diagram for explaining a sheet conveyance state in relation to a sheet thickness and a pressing force of a pickup roll.

[Explanation of symbols]

11 ... Roll support, 12 ... Rotating shaft, 14 ... Pickup roll, 15 ... Paper, 16 ... Tray (paper storage unit),
19 ... Separation roll, 20 ... Motor, 21 ... Shaft, 2
2 ... weight, 24a to 24 ... weight detection sensor, 25 ... paper detection sensor

Claims (1)

Claim: What is claimed is: 1. A sheet accommodating section for accommodating a plurality of sheets in a stack, and a sheet accommodating section in a state where the sheets accommodated in the sheet accommodating section are pressed in order from the topmost sheet by their own weight. A sheet feeding unit for feeding the sheet from the sheet feeding unit, a pushing force adjusting unit capable of adjusting the pushing force of the sheet feeding unit according to the thickness of the sheet, and a sheet feeding unit disposed downstream of the sheet storing unit in the sheet feeding direction. Paper detection means for detecting the paper sent out from the storage section,
A pressing force control unit that detects the thickness of the sheet according to the detection result of the sheet detection unit and changes the pressing force by the pressing force adjusting unit to an appropriate value, and a pressing force by the pressing force control unit. And a pressing force change amount control means for changing the amount of change of the pressing force according to the magnitude of the pressing force.