JPH05330683A - Paper feeding-separating device - Google Patents

Abstract

PURPOSE:To improve the reliability of paper feeding-separating action by adjusting-controlling the pad pressure of a friction pad. CONSTITUTION:A paper feeding-separating device of a friction pad separating system with a friction pad 3 brought into pressure contact with the outer peripheral surface of a paper feed roller 1 is provided with a piezoelectric element 13 for energizing the friction pad 3 in the direction of adjusting the pad pressure of the friction pad 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding / separating device for separating and feeding paper sheets set in a stacked state at a paper feeding position one by one.

[0002]

2. Description of the Related Art Conventionally, there are various types of paper feeding / separating devices used in a paper feeding section of a copying machine, a printing machine, etc. Among them, the paper feeding / separating device is disclosed in JP-A-55-135039. As described above, a friction pad separation type sheet feeding and separating device using a friction pad has been widely adopted. Here, a general structure of the paper feed / separation device of the friction pad separation system will be described with reference to FIG.

First, a paper feed roller 1 is rotatably supported inside a main body (not shown) of a copying machine or the like, and the pad device 2 is supported on the outer peripheral surface of the paper feed roller 1. The friction pad 3 is elastically pressed. The pad device 2 is attached to a connecting device 4 slidably in a direction in which the friction pad 3 is brought into contact with and separated from the outer peripheral surface of the paper feed roller 1. The connecting device 4 is fixed to the device body. ing. Further, a screw 5 is fixed to the connecting device 4, and a nut 6 is screwed into the screw 5, and the end surface of the nut 6 and the pad device 2 are connected.
A coil spring 7 for generating a force (pad pressure) for bringing the friction pad 3 into pressure contact with the outer peripheral surface of the paper feed roller 1 is interposed between and.

On the other hand, there is provided a paper feed cassette 9 for accommodating the papers 8 to be fed in a stacked state and mounted at a position close to the paper feed roller 1. The paper feed cassette 9 is provided.
Inside, a bottom plate 10 on which the sheets 8 are stacked and a sheet feeding coil spring 11 that generates a force (sheet feeding pressure) for pressing the stacked sheets 8 against the sheet feeding roller 1 are provided.

In such a structure, when the paper feed roller 1 is rotationally driven in the direction of arrow a, the uppermost paper 8 receives the frictional force from the paper feed roller 1 and the paper feed roller 1 and the friction pad 3 are separated from each other. The sheets 8 are drawn into the space and conveyed one by one into the main body of the device. On the other hand, when a plurality of sheets of paper 8 simultaneously enter between the paper feed roller 1 and the friction pad 3, the frictional force due to the difference in friction coefficient between the paper feed roller 1 and the paper 8 and the friction pad 3 is generated. Due to the difference, the uppermost sheet 8 is separated from the other sheets 8 and only the uppermost sheet 8 is conveyed to the inside of the apparatus body. If the friction coefficient between the paper feed roller 1 and the paper 8 is μ ₁ , the friction coefficient between the paper 8 is μ ₂ , and the friction coefficient between the paper 8 and the friction pad 3 is μ ₃ , then μ ₁ > If the relationship of μ ₃ > μ ₂ is established, the pad pressure is common, so the paper feed roller 1 and the paper 8
The frictional force that acts between the
Only the paper is separated. However, these frictional forces are obtained by “friction coefficient × pad pressure”.

However, the force acting on the sheet 8 is not only the above-mentioned frictional force between the friction pad 3 and the sheet feeding roller 1, but the sheet 8 is pressed by the sheet feeding pressure of the sheet feeding coil spring 11. Since there is also a frictional force on the part, the pad pressure required to normally perform the paper feed separation is limited.

Here, the relationship between the pad pressure and the paper feed pressure and the paper feed separation performance is examined, as shown in FIG. In FIG. 9, an area "A" is an area where double feeding occurs, an area "B" is an area where non-feeding occurs, and an area "C" is an area where normal sheet feeding and separation can be performed. In addition,
The paper feed pressure changes depending on the number of sheets of paper 8 stacked on the bottom plate 10. If the changing range is "b", the appropriate pad pressure range is "c". That is, it is necessary to maintain the pad pressure within the proper range “c” in order to normally perform the paper feed separation even when the paper feed pressure fluctuates.

The pad pressure is adjusted by rotating the nut 6 to compress or extend the coil spring 7.

[0009]

Friction pad 3
When the coil spring 7 is stretched due to the wear of the pad surface, the pad pressure may drop and fall outside the proper range. Further, a change in environment or state, for example, an increase in the apparent friction coefficient between the sheets 8 due to the deformation of the edges of the sheets 8 during cutting in the manufacturing process of the sheets 8 and the sheet 8
The appropriate range of pad pressure varies depending on the paper type. Therefore, it is necessary to maintain the pad pressure at a predetermined value or change the pad pressure according to the fluctuation of the appropriate range of the pad pressure. Further, with respect to the fluctuation of the proper range of the pad pressure, it is necessary to adjust the pad pressure with a margin such that the pad pressure is within the proper range even if the proper range fluctuates, specifically, It is necessary to set the pad pressure between d _{1 and} d ₂ on the broken line shown in FIG.

However, in the conventional friction pad separation type sheet feeding / separating apparatus, it is difficult to appropriately adjust and control the pad pressure, and when the pad pressure deviates from the proper range, double feeding of the paper 8 or A non-delivery has occurred.

[0011]

The invention according to claim 1 is
In the friction pad separation type paper feeding and separating device in which the friction pad is pressed against the outer peripheral surface of the paper feeding roller,
A piezo element that biases the friction pad in a direction in which the pad pressure of the friction pad is changed is provided.

According to a second aspect of the present invention, in a friction pad separation type sheet feeding / separating device in which a friction pad is brought into pressure contact with an outer peripheral surface of a sheet feeding roller, a sheet set at a sheet feeding position is brought into pressure contact with the sheet feeding roller. A paper feed pressure sensor for measuring the paper feed pressure is provided, and pad pressure changing means for urging the friction pad in a direction of varying the pad pressure of the friction pad based on the measurement result from the paper feed pressure sensor is provided. ..

According to a third aspect of the present invention, in a paper feed / separation device of a friction pad separation type in which a friction pad is pressed against the outer peripheral surface of a paper feed roller, a vibrator for vibrating the friction pad is provided.

[0014]

According to the invention described in claim 1, a stress is generated in the piezo element by applying a voltage to the piezo element, and the pad pressure of the friction pad is changed by the action of this stress, so that the paper feed can be normally separated. The pad pressure can be easily adjusted and controlled within an appropriate range.

According to the second aspect of the present invention, the pad pressure changing means is driven based on the measurement result of the sheet feeding pressure by the sheet feeding pressure sensor. Therefore, even if the sheet feeding pressure fluctuates, the pad pressure is fed. It is automatically changed to within the proper range where separation can be performed normally.

According to the third aspect of the invention, the friction pad vibrates by driving the vibrator, and the vibration is transmitted to the paper, whereby the separability between the paper is improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention described in claim 1 will be described with reference to FIG. It should be noted that the same parts as those described in FIG. A friction pad 3 supported by a pad device 12 is pressed against the outer peripheral surface of the paper feed roller 1, and one end of a piezo element 13 that generates a stress proportional to the applied voltage by applying a voltage to the pad device 12. Is fixed, and the other end of the piezo element 13 is fixed to the fixing portion 14 of the device body of the copying machine.

One end of a lead wire 15 is connected to the electrode portion formed on the piezoelectric element 13, and the other end of the lead wire 15 is connected to a variable voltage unit 16. When a voltage is applied to the piezoelectric element 13, the piezoelectric element 13
The acting direction of the stress generated in the is set to the direction in which the friction pad 3 is pressed against the paper feed roller 1.

In such a structure, the piezo element 13
When a voltage is applied to the piezo element 13, a stress proportional to the applied voltage is generated in the piezo element 13, and the stress causes the friction pad 3 to be pressed against the sheet feeding roller 1 and the pad pressure of the friction pad 3 to rise. Therefore, the pad pressure can be adjusted and controlled by controlling the voltage applied to the piezo element 13, and the pad pressure can be maintained within an appropriate range and the paper can be separated normally.

If the relationship between the total number of fed sheets and the wear amount of the friction pad 3 corresponding thereto is known, the pad pressure can be controlled by controlling the voltage applied to the piezo element 13 according to the number of fed sheets. Can always be maintained within the proper range.

Next, a second embodiment of the invention described in claim 1 will be described with reference to FIG. First, the pad device 2 supporting the friction pad 3 is attached to the connecting device 4 slidably in the direction in which the friction pad 3 is brought into contact with and separated from the outer peripheral surface of the sheet feeding roller 1, similarly to the conventional example described in FIG. The connecting device 4 is fixed to the device body 17 of the copying machine.

Next, a lever 18 is rotatably attached below the pad device 2 with a lever shaft 19 as a fulcrum, and a base 20 is abutted on one end of the lever 18 and is connected to the base 20. A coil spring 7 for generating a pad pressure of the friction pad 3 is interposed between the pad device 2 and the pad device 2. On the other hand, the lever 18
A piezoelectric element 21 for generating a distortion proportional to the applied voltage by applying a voltage is interposed between the other end of the piezoelectric element 21 and the coupling device 4, and the electrode portion of the piezoelectric element 21 and the variable voltage device 16 are connected to each other. It is connected via a lead wire 15. The direction of strain of the piezo element 21 when a voltage is applied to the piezo element 21 is set so as to increase the distance between the other end of the lever 18 and the coupling device 4.

In such a structure, the piezo element 21
When a voltage is applied to the piezo element 21, a distortion proportional to the applied voltage is generated in the piezo element 21, and this distortion causes the lever 18 to move.
It rotates counterclockwise around 9 as a fulcrum. By the rotation of the lever 18, the base 20 is pushed up and the coil spring 7 is compressed, the friction pad 3 is pressed against the paper feed roller 1, and the pad pressure of the friction pad 3 rises. Therefore, the pad pressure can be adjusted and controlled by controlling the voltage applied to the piezo element 21, the pad pressure can be maintained within an appropriate range, and the paper can be separated normally.

Also in this embodiment, as in the embodiment described with reference to FIG. 1, if the relationship between the total number of fed sheets and the corresponding wear amount of the friction pad 3 is grasped, the number of fed sheets can be changed. By controlling the voltage applied to the piezo element 21, the pad pressure can always be maintained within an appropriate range.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIGS. First, similarly to the embodiment described with reference to FIG. 1, the friction pad 3 supported by the pad device 12 is pressed against the outer peripheral surface of the paper feed roller 1, and one end of the piezo element 13 is fixed to the pad device 12. At the same time, the other end of the piezo element 13
It is fixed to.

Next, as in the conventional example described with reference to FIG. 8, the paper feed cassette 9 is provided at a position close to the paper feed roller 1.
Paper is loaded in the paper feed cassette 9.
A sheet feeding coil spring 1 for generating a sheet feeding pressure that presses the bottom plate 10 on which the sheets are stacked and the stacked sheets 8 against the sheet feeding roller 1.
1 and are provided. Further, a paper feeding pressure sensor 22 for electrically measuring the paper feeding pressure is provided between the bottom plate 10 and the paper feeding coil spring 11. As shown in FIG. 4, the paper feed pressure sensor 22 is attached to a strain-generating body 23 formed of hard aluminum or the like and a portion of the strain-generating body 23 where strain is likely to occur so that the strain amount of the strain-generating body 23 can be controlled. It is formed of a plurality of strain gauges 24 to be measured and a strain-flexing body fixing base 25 fixed to the strain-flexing body 23. Further, as shown in FIG. 5, the strain gauge 24 is formed by a resin film 26 and a metal strain detecting portion 27.

Lead wires 28 are drawn out from the strain gauge 24, and these lead wires 28 are strain amplifiers 29.
It is connected to the. The distortion amplifier 29 is a distortion amplifier 29.
The pad pressure necessary for normally performing the paper feed separation is calculated based on the paper feed pressure signal input from the device, and the voltage required to obtain the pad pressure is variable to be applied to the piezo element 13. Measurement control unit 3 for controlling the voltmeter 16
It is connected to 0. Then, these measurement control units 30
With the piezo element 13 and the variable voltage device 16, the pad pressure for urging the friction pad 3 in the direction of changing the pad pressure of the friction pad 3 based on the measurement result of the paper feeding pressure from the paper feeding pressure sensor 22. Change means 31 is formed.

In such a structure, the sheet feeding pressure generated from the sheet feeding coil spring 11 varies depending on the number of sheets 8 stacked on the bottom plate 10. This sheet feeding pressure is the sheet feeding pressure. It is constantly measured by the sensor 22. Based on the measurement result from the paper feed pressure sensor 22, the pad pressure required to normally perform the paper feed separation is calculated in the measurement control unit 30, and the voltage required to obtain the pad pressure is the piezo element. 13 is applied. Then, a voltage proportional to the applied voltage is generated in the piezo element 13 by the voltage application to the piezo element 13, and this stress presses the friction pad 3 against the paper feed roller 1 and increases the pad pressure of the friction pad 3.

Therefore, the pad pressure is automatically changed within a proper range in which the sheet feeding can be normally performed according to the fluctuation of the sheet feeding pressure, and the reliability of the sheet feeding is greatly improved.
Particularly, the pad pressure is d ₁ -d ₂ on the broken line shown in FIG.
If the area "C" where the normal sheet feeding and separation can be performed is changed due to the environmental change or the like, the sheet feeding and separation can be normally performed by setting it so that the sheet feeding and separating is performed.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIGS. 6 and 7. First, the pad device 3
2 has three friction pads 33a, 33b, 33
c is supported, and the friction pads 33 on both sides are supported.
b and 33c are supported via a piezoelectric vibrator 34 which is a vibrator. The piezo oscillator 34 is composed of a longitudinal oscillating piezo oscillator 34a and a shear oscillating piezo oscillator 34b.
A drive circuit 35 is connected to 4b. The friction pads 33a to 33c are arranged parallel to the center of rotation of the sheet feeding roller 1, and are in pressure contact with the outer peripheral surface of the sheet feeding roller 1.

In such a structure, by driving the drive circuit 35, the friction pads 33b, 3b are formed.
3c makes an elliptic motion as shown by an arrow e in FIG.
Moreover, at the position where it is pressed against the paper feed roller 1, it operates in the direction opposite to the rotation direction of the paper feed roller 1 (direction of arrow a), that is, the direction in which the paper 8 to be fed is returned to the paper feed cassette. Therefore, the friction pads 33b and 33c function to return the multi-fed paper 8 to the paper feed cassette side, and the paper feed separation performance is improved.

Further, the friction pads 33b and 33c
When the sheet is rotated in an elliptical locus, the sheet 8 is vibrated, and the sheet 8 whose ends are in close contact with each other at the time of cutting is released from the close contact by the vibration, and One of the causes of sending is eliminated.

In this embodiment, the piezo oscillator 34 that makes an elliptic motion with respect to the friction pads 33b and 33c has been described as an example. However, a piezo oscillator that produces a traveling wave is used as the oscillator. By arranging the piezo-vibrator so that the traveling wave is in the direction opposite to the paper feeding direction, the paper feeding / separating performance is similarly improved.

[0034]

According to a first aspect of the present invention, in a paper feed / separation device of a friction pad separation type in which a friction pad is brought into pressure contact with an outer peripheral surface of a paper feed roller, the friction is changed in a direction in which a pad pressure of the friction pad is changed. Since the piezo element for urging the pad is provided, the pad pressure can be easily adjusted and controlled by adjusting the voltage applied to the piezo element. Therefore, by maintaining the pad pressure within the proper range, This has the effect of improving the reliability of paper feed separation by the friction pad.

According to a second aspect of the present invention, in a friction pad separation type sheet feeding / separating device in which a friction pad is brought into pressure contact with an outer peripheral surface of a sheet feeding roller, a sheet set at a sheet feeding position is brought into pressure contact with the sheet feeding roller. A paper feed pressure sensor for measuring the paper feed pressure is provided, and pad pressure changing means for urging the friction pad in a direction of varying the pad pressure of the friction pad based on the measurement result from the paper feed pressure sensor is provided. Therefore, the pad pressure of the friction pad can be automatically changed within an appropriate range according to the fluctuating sheet feeding pressure. Therefore, even if the sheet feeding pressure fluctuates, the reliability of the sheet feeding separation by the friction pad can be improved. It has the effect that it can be improved.

According to a third aspect of the present invention, in a friction pad separation type paper feeding / separating device in which a friction pad is pressed against the outer peripheral surface of the paper feeding roller, a vibrator for vibrating the friction pad is provided. It is possible to vibrate the friction pad by driving, and it is possible to improve the separability between the paper sheets and improve the reliability of the paper feed separation.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the invention according to claim 1. FIG.

FIG. 2 is a side view showing a second embodiment of the invention according to claim 1.

FIG. 3 is a side view showing an embodiment of the invention described in claim 2.

FIG. 4 is an enlarged side view showing a paper feed pressure sensor.

FIG. 5 is a side view showing an enlarged strain gauge.

FIG. 6 is a front view showing an embodiment of the invention according to claim 3;

FIG. 7 is a side view.

FIG. 8 is a side view showing a conventional example.

FIG. 9 is an explanatory diagram showing the relationship between the magnitudes of pad pressure and paper feed pressure and paper feed separation performance.

[Explanation of symbols]

 1 Paper Feed Roller 3 Friction Pad 8 Paper 13,21 Piezo Element 22 Paper Feed Pressure Sensor 31 Pad Pressure Change Means 33b, 33c Friction Pad 34 Transducer

Claims (3)

[Claims] 1. A paper feed / separation device of a friction pad separation type in which a friction pad is pressed against the outer peripheral surface of a paper feed roller, and a piezo element for urging the friction pad in a direction in which the pad pressure of the friction pad is varied. A sheet feeding / separating device characterized by being provided. 2. A paper feeding / separating apparatus of a friction pad separation type in which a friction pad is pressed against the outer peripheral surface of a paper feeding roller, and a paper feeding pressure at which a paper set at a paper feeding position is pressed against the paper feeding roller is measured. A paper feed pressure sensor is provided, and pad pressure changing means for urging the friction pad in a direction in which the pad pressure of the friction pad is varied based on a measurement result from the paper feed pressure sensor is provided. Paper separation device. 3. A paper feeding / separating device of a friction pad separating type in which a friction pad is pressed against the outer peripheral surface of a paper feeding roller, and a vibrator for vibrating the friction pad is provided.