JPH05294501A - Paper sheet feeding and separating device - Google Patents

Abstract

PURPOSE:To provide a paper sheet feeding and separating device capable of feeding sheets of paper one by one securely and capable of coping with a wide range of sheet thickness. CONSTITUTION:In a paper feeding and separating device in which paper sheets 4 stacked on a paper feeding tray 5 are fed by a paper feeding roller 2 which is rotated in a paper feeding direction A, and the fed paper Sheets 4 are separated one by one by friction in a separating section 1 formed with p paper feeding roller 2 and a frictional separating member 3 provided close to the paper feeding roller 2, a paper detecting sensor 7 for detecting the paper sheets 4 transferred into the separating section 1 is provided and also a paper pressure releasing means for releasing pressure between the paper feeding roller 2 and paper sheets 4 by paper detecting signals from the paper detecting sensor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding / separating device.

[0002]

2. Description of the Related Art In an apparatus such as a PPC, a fax machine, and a printer, it is necessary that the sheets stacked on a sheet feed tray are separated and fed one by one. A large number of friction separation paper feeding systems that utilize the frictional force of the friction separation member that comes into contact with the paper feed roller are used for separating such paper. Among them, the friction separation system that uses a pad as the friction separation member is the most common. It is popular. As one example thereof, a friction pad separation sheet feeding mechanism is known. It has a paper feed roller that conveys the paper and a friction pad that is close to the paper feed roller and is inclined with respect to the paper conveyance direction. One sheet is fed by being separated by the difference in the coefficient.

[0003]

FIG. 8 shows a paper feed roller 2
And a frictional separation pad 3 as a frictional separation member is in contact with each other. The force applied to the second sheet 4 of the friction separation pad system will be described with reference to this figure. Now, the force applied to the second sheet 4b when the two sheets 4a and 4b enter from the sheet feed tray 4 stacked at the entrance of the separating unit 1 is divided into thrust and blocking force, and is described below. It is shown as an expression.

Thrust: Fa + Fb (1) where Fa = μαQ, Fb = μα (P + Wp) Blocking force: Ra + Rb (2) where Ra = μ ₁ Q, Rb = μβ (P + 2Wp) P: Paper feed Pressure between roller and paper (paper feed pressure) Q: Pressing force of friction pad on paper feed roller (friction pad pressure) Fa: Feed force received by the first paper from the second paper caused by friction pad pressure Fb : Feeding force that the second sheet receives from the first sheet due to the sheet feeding pressure Ra: Resistance force that occurs due to the friction pad Rb: Resistance force that the second sheet receives from the third sheet due to the sheet feeding pressure μα: Friction coefficient between first sheet and second sheet μβ: Coefficient of friction between second sheet and third sheet μ ₁ : Friction coefficient between friction pad and sheet Wp: Weight of sheet in this case To prevent the advance of the second sheet 4b is, F
Since it is sufficient that a + Fb <Ra + Rb, (1),
From the equation (2), (μ ₁ −μα) Q ≧ P (μα−μβ) + Wp (μα−2μβ).

Since Wp << P, if Wp≈0, then (μ ₁ −μα) Q ≧ P (μα−μβ) (3)

In the equation (3), since μ ₁ > μα, the right side is> 0. Therefore, when μα> μβ, there is a risk of double feeding.

The friction separation method as described above is the most widely used separation method in copying machines and facsimiles. This is a method that uses the difference in frictional force, and the frictional force and coefficient of friction such as the paper feed roller, separation pad, and paper that are related to the performance of paper separation depend on environmental changes such as temperature and humidity, and paper generated from paper. It fluctuates due to aging of powder, dust, rollers, etc. For this reason, there is a problem that, although a certain amount of margin is set in the initial setting, sometimes problems such as non-feeding and double feeding due to the above-mentioned causes are caused.

[0008]

According to a first aspect of the invention, the sheets stacked on the sheet feeding tray are fed by a sheet feeding roller which rotates in the sheet feeding direction, and the sheet feeding roller and the sheet feeding roller. In a paper feeding / separating device that separates the fed papers one by one by friction in a separating unit formed by a friction separating member arranged close to the roller, the papers conveyed in the separating unit. A paper detection sensor for detecting the paper pressure is provided, and a paper pressure releasing means for releasing the pressure between the paper feed roller and the paper in response to the paper detection signal of the paper detection sensor is provided.

According to a second aspect of the invention, in the first aspect of the invention, the paper pressure releasing means has a paper moving means for moving the paper stacked on the paper feed tray.

According to a third aspect of the invention, in the first aspect of the invention, the paper pressure releasing means has a roller friction member moving means for integrally moving the paper feed roller and the friction separating member in the same direction. I chose

According to a fourth aspect of the present invention, in the first aspect of the present invention, the pressure for adjusting the timing when the pressure between the paper feed roller and the paper is released in response to the paper detection signal from the paper detection sensor. A release timing adjusting means is provided.

According to a fifth aspect of the invention, in the fourth aspect of the invention, the pressure release timing adjusting means has a separation portion pressure variable adjustment means for variably adjusting the pressure of the separation portion.

[0013]

According to the present invention, in order to detect the sheet conveyed to the separating section and release the pressure between the sheet feeding roller and the sheet, the friction between the first sheet and the second sheet is eliminated. Even if the force is larger than the frictional force between the second and third sheets, it is possible to prevent double feeding.

According to the second aspect of the invention, since the pressure between the paper feed roller and the paper can be released by moving the paper side, it is possible to prevent double feeding with a simple structure. ..

According to the third aspect of the invention, since the pressure is released by moving the paper feed roller and the friction separating member together, it is possible to operate regardless of the weight of the paper.

According to the fourth aspect of the invention, the timing at which the pressure between the paper feed roller and the paper is released in response to the paper detection signal from the paper detection sensor is adjusted. Can be separated into

According to the fifth aspect of the invention, since the pressure of the separating portion can be varied, it is possible to prevent the sheet from being unfed even if the pressure between the sheet feeding roller and the sheet is released when the sheet is thick. It becomes possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claims 1 and 2 will be described with reference to FIG. The same parts as those in the conventional example (see FIG. 8) are designated by the same reference numerals. FIG. 1 shows a state of the separating unit 1 of the paper feeding / separating apparatus. A paper feed roller 2 that rotates in the paper feed direction A is provided in the separation unit 1, and a friction separation pad 3 as a friction separation member is arranged at a position close to the paper feed roller 2. There is. The friction separation pad 3 is biased toward the surface of the paper feed roller 2 by a friction separation pad pressure spring 6. Further, the sheets 4 are stacked on the sheet feeding tray 5, and are drawn in order from the uppermost sheet 4a to the sheet feeding roller 2 side.

In the paper feeding / separating apparatus having the separating section 1 as described above, here, the following mechanism is provided. That is, the paper 4 conveyed into the separation unit 1
A paper detection sensor 7 for detecting the paper pressure is provided, and a paper pressure release means for releasing the pressure between the paper feed roller 2 and the paper 4 by the paper detection signal of the paper detection sensor 7 is provided. The paper pressure releasing means is composed of a paper moving means 8 for moving the papers 4 stacked on the paper feed tray 5. The sheet moving means 8 includes a bottom plate pressing spring 9 attached to the bottom surface of the sheet feeding tray 5, a pressure releasing arm 10, and an arm rotating shaft 1.
It consists of 1.

In such a structure, the paper feed roller 2 is rotated by a paper feed signal sent from a controller (not shown),
The paper 4 is sent to the separation unit 1 between the paper feed roller 2 and the friction separation pad 3. After that, when the front end of the paper 4 is inserted into the separation unit 1, the paper detection sensor 7 detects the front end of the paper 4,
A plunger (not shown) connected to the arm rotating shaft 11 operates to lower the sheet 4 as a whole via the pressure releasing arm 10 and the spring 9. As a result, the sheet feeding pressure is released, so that it is possible to reliably prevent double feeding in the separating unit 1.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIGS. The description of the same parts as those of the embodiment of the invention described in claim 1 (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

In this embodiment, as the paper pressure releasing means, a roller friction member moving means 12 for integrally moving the paper feed roller 2 and the friction separating pad 3 in the same direction is used instead of the paper moving means 8 described above. It is provided. 2 and 3
Shows the structure of the roller friction member moving means 12. First, in FIG. 2, the roller friction member moving means 12 includes a paper feed roller shaft 13, a connecting arm 14, and
It is constituted by the friction separation pad shaft 15. The connecting arm 14 includes a paper feed roller shaft 13 and a friction separation pad shaft 1.
It has the function of unifying the movement with 5.

Further, in FIG. 3, the roller friction member moving means 12 comprises a paper feed roller shaft 13 and a connecting arm 14.
A friction separating pad shaft 15, a potch 16 provided on the connecting arm 14, a moving arm 17, an arm rotating shaft 18, and a spring for fixing the moving arm 17 to a position at the start of feeding. And 19. Figure 4
[FIG. 3] is a front view seen from a sheet feeding direction A.

In such a configuration, the operation principle of FIG. 2 is included in the operation principle of FIG.
A description will be given with reference to FIG. Now, when a paper feed signal is input from the control unit, the paper feed roller 2 is rotated and the paper 4 is separated from the separation unit 1.
Sent to. When the paper detection sensor 7 detects the paper 4, a plunger (not shown) connected to the arm rotation shaft 18 is actuated to move the moving arm 17 and the connecting arm 1.
4, the movement is transmitted to the paper feed roller 2 and the friction separation pad 3. As a result, the integrated paper feed roller 2 and friction separation pad 3 move in a direction B diagonally upward to the left, and the pressure between the paper feed roller 2 and the paper 4 is released. It is possible to reliably prevent double feeding of the sheets. Therefore, from the above, in the above-described first embodiment, when the weight of the sheet 4 becomes heavier than a certain amount, the reaction of pressure release may slow down, but the configuration of this embodiment is used. As a result, the reaction time is short and quick response is possible, and the reliability can be improved.

Next, an embodiment of the invention described in claim 4 will be described with reference to FIGS. 5 and 6. The description of the same parts as those of the embodiment of the invention described in claim 1 (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

FIG. 5 shows a thin sheet 4 and FIG. 6 shows a thick sheet 4 when the sheet 4 is conveyed to the separating section 1. In this case, the thin paper 4 has reached the position of the X point, but the thick paper 4 has still reached the Y point. In this case, the state when the paper detection sensor 7 detects the paper 4 is different (in other words, when the sensor reacts when the point Y in FIG. 6 is reached, in the case of the thin paper 4 in FIG. The paper 4 has not yet reached the separation unit 1).

Therefore, in the present embodiment, the paper detection sensor 7 is arranged at the position of the point Y, and the paper detection signal from the paper detection sensor 7 is received to control the pressure between the paper feed roller 2 and the paper 4. A pressure release timing adjusting means (not shown) for adjusting the release timing is provided. Specifically, by arranging the paper detection sensor 7 at point Y, the case of thick paper 4 is dealt with first. Next, in order to cope with the case of the thin paper 4, a delay control circuit for delaying the timing of releasing the pressure according to the linear velocity of the paper feed roller 2 is incorporated in the pressure release timing adjusting means, and the control unit A condition for correcting the delay is set in advance before the input of the paper feed signal from. Therefore, by providing the pressure release timing adjusting means in this way, it is possible to respond to a wider range of the thickness of the sheet 4, and it is possible to further improve the reliability. Instead of fixing the paper detection sensor 7 to the Y point, a method may be adopted in which the sensor is movable and the timing of pressure release is changed.

Next, an embodiment of the invention described in claim 5 will be described with reference to FIG. The description of the same parts as those of the embodiments of the invention described in claims 1 and 4 (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

The thick paper 4 can be seen in FIG.
It is difficult for the leading edge of the sheet 4 to enter the separating section 1. The greater the pressure in the separation section 1, the greater the effect. If the pressure between the paper feed roller 2 and the paper 4 is released before the paper 4 bites into the separating unit 1, the paper 4 loses its thrust and is not fed.

Therefore, in this embodiment, the above-mentioned claim 4 is used.
The pressure release timing adjusting means in the invention described above is provided with a not-shown separating portion pressure variable adjusting means for variably adjusting the pressure of the separating portion 1. Specifically, the holder 20 of the friction separation pad pressure spring 6 (the movement of which is restricted only in the contact direction with the sheet feeding roller 2 like the spring) is moved in the direction C by an unillustrated plunger. The pressure of the separation unit 1 is maintained at about 70 to 80% before the paper detection sensor 7 detects the paper, and the pressure is maintained at a specified value after the paper detection by a method such as. As a result, even in the case of the thick sheet 4, it is possible to firmly enter the separating section 1, so that the thickness of the sheet 4 can be handled in a wider range.

[0031]

According to the present invention, the sheets stacked on the sheet feeding tray are fed by the sheet feeding roller rotating in the sheet feeding direction, and the sheet feeding roller and the sheet feeding roller are close to each other. A paper feed / separation device that separates the fed paper sheets one by one by friction in a separation portion formed by a friction separation member that is disposed in order to detect the paper sheets conveyed in the separation portion. Since the paper detection sensor is provided, and the paper pressure releasing means for releasing the pressure between the paper feed roller and the paper in response to the paper detection signal of the paper detection sensor is provided, the paper conveyed to the separation unit in this way. Is detected and the pressure between the paper feed roller and the paper is released, the frictional force between the first and second sheets becomes larger than the frictional force between the second and third sheets. Even if you do not want to feed multiple sheets, you can ensure that the sheets are separated. One in which it is bet.

According to the second aspect of the invention, in the first aspect of the invention, the paper pressure releasing means has the paper moving means for moving the paper stacked on the paper feed tray. By moving the paper side, it is possible to release the pressure between the paper feed roller and the paper, and thus it is possible to prevent double feeding with a simple structure,
It can be made at a low cost.

According to a third aspect of the present invention, in the first aspect of the invention, the paper pressure releasing means has a roller friction member moving means for integrally moving the paper feed roller and the friction separating member in the same direction. Since it was set, by moving both the paper feed roller and the friction separating member to release the pressure,
It can be operated regardless of the weight of the sheets, and as a result, a large number of sheets can be set at one time.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the pressure for adjusting the timing when the pressure between the paper feed roller and the paper is released in response to the paper detection signal from the paper detection sensor. Since the release timing adjustment means is provided,
By adjusting the timing when the pressure between the paper feed roller and the paper is released in response to the paper detection signal from the paper detection sensor, it is possible to reliably separate thick paper to thin paper. It is possible to support a wide range of types.

According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the pressure release timing adjusting means has a separating portion pressure variable adjusting means for variably adjusting the pressure of the separating portion. By changing the pressure, it is possible to eliminate the problem of feed failure even if the pressure between the paper feed roller and the paper is released in the case of thick paper. It is possible to correspond.

[Brief description of drawings]

FIG. 1 is a side view of a paper feeding / separating device according to an embodiment of the present invention.

FIG. 2 is a side view showing an embodiment of the invention according to claim 3;

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

FIG. 4 is a front view of FIG. 3 viewed from the sheet feeding direction.

FIG. 5 is a side view showing a state in which a thin sheet has entered the separating portion, which is an embodiment of the invention described in claim 4.

FIG. 6 is a side view showing a state in which a thick sheet has entered the separating portion, which is an embodiment of the invention described in claim 4;

FIG. 7 is a side view showing an embodiment of the invention according to claim 5;

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

[Explanation of symbols]

 1 Separation Unit 2 Paper Feed Roller 3 Friction Separation Member 4 Paper 5 Paper Feed Tray 7 Paper Detection Sensor 8 Paper Moving Means 12 Roller Friction Member Moving Means

Claims (5)

[Claims] 1. A paper feed roller that rotates in the paper feed direction, feeds paper stacked on a paper feed tray, and the paper feed roller and a friction separating member that is disposed in proximity to the paper feed roller. In a paper feeding / separating device that separates the fed papers one by one by friction in a separating unit formed by, a paper detection sensor for detecting the papers conveyed in the separating unit is provided. A paper feeding / separating device comprising a paper pressure releasing means for releasing a pressure between the paper feeding roller and the paper according to a paper detection signal of a paper detection sensor. 2. The paper feeding / separating apparatus according to claim 1, wherein the paper pressure releasing means has a paper moving means for moving the paper stacked on the paper feeding tray. 3. The paper feeding / separating apparatus according to claim 1, wherein the paper pressure releasing means has a roller friction member moving means for integrally moving the paper feeding roller and the friction separating member in the same direction. 4. A pressure release timing adjusting means for adjusting the timing when releasing the pressure between the paper feed roller and the paper in response to the paper detection signal from the paper detection sensor. 1. The paper feeding / separating device according to 1. 5. The paper feeding / separating apparatus according to claim 4, wherein the pressure release timing adjusting means has a separating portion pressure variable adjusting means for variably adjusting the pressure of the separating portion.