JPH0114129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for feeding sheet-like paper, and particularly to a copying machine, an electronic file, a facsimile,
The present invention relates to an air suction type sheet paper suction device that sucks air into sheet paper used to reliably feed sheet paper one by one in a printing machine or the like.

Conventionally, a device that feeds sheets of paper or originals, etc. stacked on a paper feed table one by one to a predetermined position, has a paper feed roller that faces the stacked sheets of paper. Generally, paper is fed one sheet at a time by rotating a paper roller.
Widely used. A device using this paper feed roller feeds a single sheet by utilizing the friction of the roller. Therefore, it easily damages the sheet paper (manuscript), stains the surface of the sheet paper, easily causes slippage on art paper or coated paper with a low surface friction coefficient, and friction caused by paper dust and changes in the roller material over time. This method has many drawbacks, such as the tendency to cause paper feeding errors due to a decrease in coefficients.

In order to overcome these drawbacks, various apparatuses have been proposed that use air suction to adsorb sheet paper and convey the adsorbed paper. This device that uses air suction connects a sheet suction unit with an air suction port on the bottom and a suction air casing with a negative pressure chamber inside, and allows multiple sheets stacked on a paper feed tray to be collected. The uppermost sheet of sheet paper is sucked at the bottom surface of the sheet paper suction section, and the sucked sheet is conveyed. However, in the above-mentioned sheet paper suction device, the position of the sheet paper suction unit during suction is fixed, so the gap between the suction port of the sheet paper suction unit and the top sheet paper must be made uniform throughout. Poor adsorption occurs. In other words, if a part of the suction part comes into contact with a sheet of paper and a gap is created in the other part, the suction force (negative pressure) will be greatly reduced and the sheet will not be able to be suctioned. Therefore, the suction port of the sheet paper suction unit must be placed with high accuracy with respect to the sheet paper, and the adjustment thereof becomes extremely troublesome. Furthermore, if the surface of the uppermost sheet paper is uneven, the suction port and the paper inevitably do not come into close contact with each other and a gap is created, and air flows in through this gap, resulting in poor suction.

Furthermore, conventionally, if the sheet paper is not suctioned by the above-described suction operation, it is considered that the sheet paper cannot be suctioned, and the sheet paper is currently fed manually.

In view of the above-mentioned drawbacks, the present invention provides a sheet paper suction device that enables reliable suction without causing suction failure and eliminates the need for manual work. Further, the present invention provides an apparatus that can perform a suction operation reliably even if the interval between the sheet paper suction unit and the sheet paper is not precisely arranged.

The present invention connects the sheet paper suction section to the negative pressure chamber through a flexible duct, giving the suction section a degree of freedom and ensuring reliable suction even if the distance from the sheet paper is not uniform. It makes it possible. DESCRIPTION OF THE PREFERRED EMBODIMENTS An air suction type sheet paper suction device will be described in detail below with reference to the drawings showing an embodiment of the present invention.

1 and 2 are side sectional views showing an air suction type sheet paper suction device according to the present invention, FIG. 3 is a rear view showing substantially the entire sheet paper suction device, and FIG. 4 is a view of the sheet paper suction port. FIG. 5 is a bottom view showing an example of the suction port, FIG. 5 is an explanatory diagram for explaining the operation of the present invention, and FIG. 6 is a circuit configuration diagram for repeating the suction operation of the present invention.

1 in the figure is a suction air casing (hereinafter referred to as the air suction box) which is equipped with a negative pressure chamber 2 inside, as shown in Figures 1 and 2. In addition, a sheet suction section 5 having a plurality of air suction ports 6 on the bottom surface is connected via a flexible duct (hereinafter referred to as duct) 3 made of, for example, cloth-filled rubberized cloth. Each end of the duct 3 is fixed to the inner surface of the air suction box 1 and the inner surface of the side plate 5-1 of the sheet paper suction section ₅ by fixing members 4, respectively. The duct 3 may be formed into a bellows-like shape so as to be deformable as shown in the figure, but it may also be formed from an elastic member whose length changes.

The sheet paper suction unit 5 is constantly pulled with a downward force by a tension member 8 such as a spring. The tension member 8 has one end fixed to the upper part of the U-shaped tension angle 9 and the other end fixed to the lower part of the U-shaped stopper angle 7.
The tension angle 9 is fixed to a side plate 5-1 forming the sheet suction section ₅ , and the stopper angle 7 has an upper portion fixed to the air suction box 1. Also, the other tension member 8
One end is fixed to a slider 15 that is slidably provided on the slide shaft 14, and the other end is fixed to a slider stopper 10 that restricts sliding of the slider 15 to the lower limit. In other words, both tension members 8
Due to the biasing force, the U-shaped tension angle 9
The sheet paper suction unit 5 is constantly pulled downward until the lower piece of the stopper angle 7 contacts the slider 15 and the slider stopper 10 (see the solid line diagram in FIG. 1). ). Note that one end of the slide shaft 14 is fixed to one side plate of the upper air suction box body 1.

A rotation angle 13 is rotatably supported on the slider 15 via a bearing 11 on the rotation shaft 12 in the direction of arrow A. 5
− Fixed to ₁ . Therefore, since the duct 3 can be deformed as shown by the broken line, the sheet paper suction section 5 has a degree of freedom in which it can move up and down in the direction of arrow B within the length range of the interval l shown in the figure along the slide shaft 14. ing. Further, the sheet paper suction unit 5 is rotated within a range l around the rotation axis 12.

Next, referring to FIG. 2, the configuration of a pressure roller for pressing the top sheet of paper will be described.
In the figure, 16 is a pressure roller. This pressure roller 1
6 is rotatably provided via a bearing 17 around a shaft 18 supported by an angle 43. The angle 43 is fixed to the end of a vertically movable slider 21 that passes through a bearing member 20 provided at the rear of the air suction box 1. An engagement piece 21a is provided at the upper end of the slider 21, with which one end of an arm 22 attached to the rotating shaft 28 engages. Also, the angle 2 attached to the rotating shaft 28
One end of 3 is connected to latch 2 connected to solenoid 25.
6 is engaged. turning on the solenoid 25;
The OFF operation causes the slider 21 to move up and down via the latch 26 over a distance l. When the solenoid 25 is on, the pressure roller 16 can move upward by l. With the above-described configuration, the pressure roller 16 can be moved up and down by the distance l by means of the solenoid 25.

Further, in FIG. 3, reference numeral 33 is a motor for driving, particularly rotating, the entire sheet paper suction device. This motor 33 is attached to the motor mounting angle 3
It is attached to 7. Reference numeral 29 is air suction box body 1
A support member 30 integral with a drive shaft 36 is attached to the lower part of the base plate 29 . The drive shaft 36 passes through a bearing part of a bearing (not shown) provided on the support member 31 and fixed to the upper part of the motor mounting angle 37. Further, the rotational force from the motor 33 is transmitted to the drive shaft 36 through engagement between a worm 34 provided on the rotation shaft of the motor 33 and a worm wheel 35 fixed to the drive shaft 36 . In addition, code 3
Reference numeral 2 indicates a flexible duct that connects the suction blower (not shown) and the air suction box body.

The motor 33 is controlled and driven by a speed control circuit 61 shown in FIG. The speed control circuit 61 is connected to the sheet paper suction unit 5.
After the suction operation, the motor 33 is rotated based on the rotation command signal, and the sheet paper suction unit 5 is rotated. In addition, the speed control circuit 61
The motor 33 is controlled to rotate while being gradually accelerated, and the sheet paper suction unit 5 is gradually accelerated and raised. Furthermore, if the sheet paper suction detection circuit 62, which will be described later, does not detect any sheet paper to be sucked, the speed control circuit 61 uses this signal to reverse the motor 33 and return the sheet paper suction unit 5 to its original position. , repeat the suction operation.

Next, referring to FIG. 4, the suction port 6 of the sheet paper suction section 5 will be explained. As shown in the figure, the suction port 6
has two large suction ports 6a facing each other near the edge of the paper size on the bottom of the sheet paper suction unit 5;
It consists of many small suction ports 6b between them. Further, a large number of small suction ports 6c are provided on the left side of the large suction port 6a. This small suction port 6c is provided to suction not only _B5 or _B4 size sheets but also _A4 or _A3 size sheets without slack. Note that A ₃ or B ₄ corresponds to the width direction, and B ₅ or A ₄ corresponds to the length direction.

The suction force of the suction port 6 for sucking air is controlled by a suction force control circuit 63 shown in FIG. The suction force control circuit 63 controls the suction force by controlling the rotation of a suction blower or the like.
This is done via the air suction port 6 based on the suction command.
Further, when a sheet non-detection signal is input from the sheet paper suction detection circuit 62, a signal for repeating the suction process to perform the suction operation again is outputted. At this time, the suction force control circuit 63 counts the non-detection signal by, for example, providing a counter or the like.
When the count reaches a certain number, the suction power is strengthened,
Repeat the suction operation.

The operation of the device constructed as described above will be explained below with reference to FIGS. 5 and 6.

First, in FIG. 5, reference numeral 39 indicates a large number of sheets stacked on the upper part of a paper feed table 40 which is provided to be movable up and down in the direction of arrow C, and 42 indicates a guide plate for the sheets being conveyed. , 41 indicates a sheet conveying device in a standby state. In this device, mode settings are made to change the suction force depending on whether the sheet to be conveyed is thin or thick. If the sheet of paper is thin, the suction force is set so that it does not strongly suck many sheets of paper, and if the sheet of paper is thick, the suction force is set to a value that can attract the sheet of paper. In other words, the suction force control circuit 6 shown in FIG.
3, for example, in the case of thin sheet paper, the suction blower or the like is controlled to make the suction force smaller than in the case of thick paper, depending on the mode setting. As a result, the suction force is weakened and the sheet paper suction unit 5 performs a suction operation for thin paper.

Now, in FIG. 5a, when a signal instructing the start of sheet feeding is output, the sheet feeding table 40 moves the uppermost sheet 39' of the sheets 39 stacked on it to the sheet feeding tray 40. It has risen in the direction of arrow C to a position where the bottom surface of the adsorption section 5 and the pressure roller 16 are pushed up to some extent. In this state,
Air is sucked from a plurality of air suction ports 6 provided on the bottom surface of the sheet paper suction unit 5. That is, a suction blower (not shown) starts suctioning the sheet paper. At this time, even if the stopping position of the paper feed table 40 is incorrect from the normal position, that is, even if the distance between the sheet paper and the suction port 6 is even, the above error will be corrected (absorbed) by the action of the duct 3. Ru. This is because, as explained in FIG. 1, the duct 3 allows the sheet paper suction unit 5 to move up and down by the maximum length l with respect to the air suction box 1, and to rotate within that range. Since it is flexible, if the length error is less than the above l, the uppermost sheet paper 39' will surely come into close contact with the suction port 6. Further, even if the surface of the paper becomes uneven due to changes in environmental conditions, wrinkles, etc., the suction port 6 and the sheet paper 39 can be kept in close contact with each other. Therefore, the suction operation of the sheet paper is reliably performed by starting the air suction operation by the suction blower, and it is possible to prevent a decrease in the suction force due to air flowing into the air suction port that occurs when the adhesion is insufficient. In this state, the sheet paper 39 is under pressure by the pressure roller 16.

After the sheet paper 39 is attracted as described above, the operation shown in FIG. 5b is performed. This operation consists of rotating the entire device in the direction of arrow E from the state shown in FIG. 5a. This rotation is performed by the motor 33 using the contact point between the lower part of the pressure roller 16 and the uppermost sheet 39' as a fulcrum while maintaining the suction operation.
(See Figure 3). In this case, the speed control circuit 62 increases the rotation of the sheet paper suction unit 5 while gradually accelerating it. In other words, the speed control circuit 62
3 speed control is performed, and the rotation speed is gradually increased. The rotation of the sheet paper suction section 5 is stopped when it reaches a predetermined position, that is, a sheet paper transport position, by a position detection means (not shown). At this time, the sheet paper suction unit 5 is held at the position shown in FIG. 5b.

By raising the rotation while gradually increasing the acceleration in this manner, air can easily flow between the uppermost sheet 39' and the next sheet, making it easier to separate the two. In addition, since the sheet paper suction unit 5 is gradually accelerated and raised, air can be prevented from flowing between the paper sheet 39' being sucked into the suction port 6, and suction errors due to a decrease in suction force can be suppressed. can be prevented. In other words, if the sheet paper 39' that is being sucked is suddenly pulled up, a large force acts on the sheet paper 39' to move it away from the suction port 6, making it easier for air to flow in, resulting in frequent suction errors. This can be prevented by gradually accelerating the speed using the speed control circuit.

Next, in the state shown in FIG. 5b, if the uppermost sheet paper 39' is not sucked by the suction port 6 of the sheet paper suction unit 5, the sheet paper suction detection circuit 62 shown in FIG. 6 detects this. . This sheet paper suction detection circuit 62 detects the presence or absence of suction, and repeats the above-described suction operation based on this detection. The circuit also detects, for example, a change in the load current of a suction blower, and thereby determines whether or not the sheet paper 39 is attracted to the suction port 6. For example, if the load current of the suction blower becomes small, it is detected that a sheet of paper is attracted to the suction section 5. Instead of such a detection means, a micro switch or an optical detection means may be provided in the sheet paper suction unit 5 to detect whether or not a sheet paper is attracted. Therefore, if the sheet paper suction detection circuit 62 does not detect sheet paper suction in the state shown in FIG. 5b, the same suction operation as described above is repeated (if it outputs a non-detection signal). That is, if the non-detection signal is output, for example, the suction force control circuit 63 counts it and outputs a signal for repeating the suction operation to the speed control circuit 61. Therefore, the motor 33 is reversed and the fifth
The sheet paper suction unit 5 is returned to the position shown in Figure a. Then, the suction force control circuit 63 suctions air from the suction port 6 again and repeats the suction operation. The above-described suction operation is repeated, and if the sheet paper 39 cannot be suctioned even after repeating this a certain number of times, the detection circuit 62 outputs a non-detection signal to that effect. Based on this signal, the suction force control circuit 63 counts a certain number, increases the suction force, and instructs to repeat the suction operation again. Repeat the suction operation several times with this suction force strong, and if the suction is still not possible,
Immediately stop all operations. At the same time, the alarm circuit 64 is activated to notify that suction is not possible.

Further, in the state shown in FIG. 5b, the pressure roller 16 is
Although it moves slightly in the direction of arrow G, it is pressed by the constant pressure of the sheet paper 39. Therefore, if there are multiple sheets of paper attracted, the pressure roller 16
The stiffness of the paper becomes stronger due to the effect of pressure. Therefore, the pressing force of the pressure roller 16 overcomes the adhesion force between the sheets, causing the next and subsequent sheets of the adsorbed sheet to fall. The fallen sheet returns to its original position (normal position) without shifting due to the pressure effect of the pressure roller 16.

Meanwhile, as described above, the top sheet paper 3
If the suctioned sheet falls for some reason after the sheet 9' is properly suctioned, the sheet suction detection circuit 62 detects the fall. As a result, the operations shown in FIGS. 5a and 5b are repeated again.

Note that the sheet paper suction unit 5 sucks the sheet paper using the air suction port 6;
From the shape of the air suction port shown in the figure, the center portion of the sheet paper is sucked by the small suction port 6b. Therefore, the center portion of the sucked sheet does not sag. In Fig. 4, if the size of the sheet paper is A ₄ or A ₃ , one side edge will be out of the large suction port 6a, but since the small suction port 6c is provided in that part, the sheet paper will The side edges are also stably attracted without sagging. In addition, in the case of _B5 or _B4 size sheet paper, if the paper does not face the small suction port 6c and there is a risk that the suctioned sheet paper may fall due to a decrease in suction force, for example, the shutter mechanism established,
The small suction port 6c may be shielded.

As described above, when the uppermost sheet 39' is suctioned, the leading edge of the sheet is then caught by the sheet transport device 41 and transported in the direction of arrow H as shown in FIG. 5c. Start. When carrying out this conveyance, the suction operation and the pressure applied by the pressure roller 16 hinder the conveyance. Therefore, the suction operation is stopped, and the pressure roller 16 is pulled up in the G direction by driving the solenoid 25 (second
(see figure). As a result, the sheet paper can be smoothly conveyed without being damaged under any load.

By repeating the above-described operations shown in FIGS. 5a, b, and c, the stacked sheets can be sequentially conveyed. By repeating such conveyance, the surface of the uppermost sheet paper gradually decreases. However, even if the surface of the sheet paper is lowered, the flexible duct 3 ensures close contact with the bottom surface of the sheet suction section 5.

As described above, according to the sheet paper suction device of the present invention, the air suction ports of the sheet material suction section include a pair of large suction ports facing each other near the edge of the paper size, and a space between the large suction ports and one of the large suction ports. Each of the large suction ports has a large number of small suction ports on its outer end side, and the connection side between the air suction ports and the suction air casing on the opposite side is connected to the suction air casing via a flexible duct. The support angle provided on one side wall of the sheet material suction section is rotatably supported so that it can swing in the air suction direction by the expansion and contraction of the flexible duct. By making the interval more precise, even if the surface condition of the sheet paper is poor, it is possible to ensure close contact between the sheet paper suction section and the sheet paper, which can greatly contribute to preventing the above-mentioned suction mistakes.

[Brief explanation of drawings]

1 and 2 are side sectional views showing a sheet paper suction device according to the present invention, FIG. 3 is a rear view showing substantially the entire sheet paper suction device according to the present invention, and FIG. 4 is a sheet paper suction device according to the present invention. A sectional view showing a specific example of the suction port of the suction device, FIGS. 5A, 5B, and 5C are explanatory diagrams for explaining the operation of the present invention, and FIG. 6 is an explanatory diagram of the operating circuit in the present invention. 1: Air suction box body (suction air casing), 2: Negative pressure chamber, 3: Flexible duct,
5: Sheet paper adsorption section, 6: Air suction port, 3
3: Motor, 39: Sheet paper, 40: Paper feed tray,
61: Speed control circuit, 62: Sheet paper adsorption detection circuit, 63: Suction force control circuit.

Claims (1)

[Claims] 1. A sheet material suction unit having a plurality of air suction ports on the bottom surface and a suction air casing having a negative pressure chamber inside, and capable of handling a plurality of sheets stacked on a paper feed base plate. In an air suction type sheet material adsorption device that adsorbs the uppermost sheet material on the bottom surface of the sheet material adsorption section, and moves the sheet material adsorption section to pull up the uppermost sheet material, the sheet material adsorption section comprises: The air suction ports include a pair of large suction ports facing each other near the edge of the paper size, and a large number of small suction ports between the large suction ports and on the outer end side of the one large suction port. At the same time, the connection side of the air suction port and the suction air casing on the opposite side is connected to the suction air casing via a flexible duct, and a support angle provided on one side wall of the sheet material suction section is connected to the suction air casing through a flexible duct. An air suction type sheet paper suction device that is rotatably supported so that it can swing freely in the air suction direction by expanding and contracting the duct.