JPS646090B2 - - 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 in order to reliably feed the paper sheets one by one in a printing machine or the like.

Conventionally, devices that feed sheets of paper stacked on a paper feed tray one by one to a predetermined position include:
It is common that a paper feed roller is provided facing the stacked sheets of paper, and the paper is fed one by one by rotating the paper feed roller, and is widely used. Devices that use this paper feed roller use roller friction, which can easily damage the sheet original, stain the sheet paper, easily cause slipping on art paper or coated paper that has a low surface friction coefficient, and may also be susceptible to paper dust or roller material. It has many drawbacks, such as the tendency to cause feeding errors due to a decrease in the coefficient of friction caused by changes over time.

In order to overcome these drawbacks, various means using air suction have been proposed. 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 suctioned by the bottom surface of the sheet paper suction section, and the suctioned sheet paper is conveyed.

However, the conventional sheet paper suction device
Since the position of the sheet paper suction unit during suction is fixed, the distance between the suction port of the sheet paper suction unit and the uppermost sheet paper is not uniform throughout, resulting in poor suction. Therefore, unless the suction port of the sheet paper suction unit is accurately positioned with respect to the sheet paper, the suction operation will not be performed completely. In addition, if the surface of the top sheet paper is uneven, the suction port and the paper will not come into close contact with each other, and a gap will occur, and air will be sucked through the gap.
Poor adsorption occurs.

Furthermore, it is common practice to provide the suction port in the sheet paper suction unit corresponding to the width of the paper, which requires a strong air suction force to adsorb the sheet, and also makes it difficult to handle a large number of sheets at the same time. Because of the suction, it was not possible to feed sheets one by one, and a large suction means was required for air suction.

In view of the above-mentioned drawbacks, the present invention provides suction ports of a sheet paper suction unit facing both ends of the sheet paper, and also includes a portion that is held by the suction ports and a large number of other parts that are smaller than the above-mentioned suction ports. It is characterized by forming a suction port. That is, the suction ports at both ends suction the uppermost sheet of paper, and the central portion and other small suction ports prevent the paper from sagging, making it possible to securely suction the paper. In addition, since the suction force at the center is smaller, air can flow in between the next sheet and the next sheet, making it easier to separate the next sheet and ensuring single-sheet feeding. . Furthermore, since there are multiple suction ports instead of just one, the suction force can be reduced compared to conventional ones.
It is hoped that the device will be smaller.

Further, the present invention can be used even if the accuracy of the distance between the suction port of the sheet paper suction unit and the top sheet paper is not very good, or the surface condition of the top sheet paper to be sucked is not good due to changes in the environment. It is an object of the present invention to provide a highly reliable air suction type sheet paper suction device that can reliably suction the topmost sheet paper even when the topmost sheet paper is sucked.

Below, according to the drawings showing one embodiment of the present invention,
The air suction type sheet paper suction device will be explained in detail.

1 and 2 are side sectional views showing the air suction type sheet paper suction device of the present invention, FIG. 3 is a rear view of the sheet paper suction device, and FIG. 4 is a suction port in the sheet paper suction unit of the present invention. FIG. 5 is a diagram for explaining the operation, and FIG. 6 is an operation circuit diagram for explaining the operation of the present invention. Identical parts in each figure are designated by the same reference numerals.

1 in the figure is a suction air casing equipped with a negative pressure chamber 2 inside, as shown in FIGS. A sheet paper suction section 5 having a plurality of air suction ports 6 on the bottom surface is connected through a flexible duct 3 consisting of a flexible duct 3 having a plurality of air suction ports 6 on the bottom surface thereof.

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 the sheet paper adsorption section 5
The stopper angle 7 is fixed to the side plate _5-1 forming the suction air casing 1.
The upper part is fixed. The other tension member 8 has one end fixed to a slider 15 that is slidably provided on the slide shaft 14, and is fixed to the tip of the slide shaft 14 that restricts the slide shaft of the slider 15 to the lower limit. The other end is fixed to the slider stopper 10. In other words, due to the biasing force of the tension member 8, the lower part of the U-shaped tension angle 9 always attracts the sheet paper to the lower part of the stopper angle 7 and to the respective abutting positions of the slider 15 and the slider stopper 10. Section 5 is tensioned (see solid line diagram in FIG. 1).

A rotating angle 13 is rotatably supported on the slider 15 via a bearing 11 on the rotating shaft 12 in the direction of arrow A, and the rotating angle 13 is connected to the side plate 5 _-1 of the sheet paper suction unit 5. is fixed. Therefore, since the flexible 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 B direction along the slide shaft 14 by the length of the distance l shown in the figure. Further, it can rotate around the rotating shaft 12 within a range of an interval l.

Next, referring to FIG. 2, the configuration of a pressure roller for pressing the uppermost sheet will be described. In the figure, 16 is a pressure roller. This pressure roller 16 is rotatably provided via a bearing 17 around a shaft 18 supported by an angle 43. The angle 43 is connected to the bearing member 20 provided at the rear of the suction air casing 1.
It is attached to a vertically movable slider 21 that passes through the. A locking piece 21a with which one end of an arm 22 attached to the rotating shaft 28 engages with the upper end of the slider 21.
is provided. Also, one end of the angle 23 attached to the rotation shaft 28 is engaged with a latch 26 connected to the sonoid 25. The on/off operation of the sonoid 25 causes the slider 21 to move up and down by a distance l via the latch 26. With the above configuration, the pressure roller 16 can be moved up and down by the distance l using the sonoids 25.

In FIG. 3, reference numeral 33 is a motor for driving the entire apparatus of this embodiment, and this motor 33 is attached to a motor mounting angle 37. A base plate 29 is directly connected to the suction air casing 1, and 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 portion (not shown) of a bearing provided on the support member 31 fixed to the upper part of the motor mounting angle 37. The drive shaft 36 also receives rotational force from the motor 33 through a worm 34 provided on the rotation shaft of the motor 33 and a worm wheel 35 provided on the drive shaft 36 . Note that 32 indicates a joint (not shown) that connects the suction blower and the suction air casing 1.

Next, referring to FIG. 4, the suction port 6 of the sheet paper suction section 5, which is a feature of the present invention, will be explained. As shown in the figure, for example, _a large suction port _6a for obtaining most of the suction force to adsorb the sheet paper, and a large suction port 6a for obtaining most of the suction force for adsorbing the sheet paper, and A small suction port 6b consisting of a large number of small openings is connected between the opening 6a and the bottom surface of the sheet paper suction unit 5, that is, the surface facing the sheet paper for suction. It is arranged and formed. Here, on the left side of the large suction port 6a on the left side of the figure, there are many more small suction ports 6.
c. This is designed to suction not only _B5 or _B4 size sheet paper but also _{A4 or A3} size sheet paper without sag _. If it is not used, there is no need to provide the small suction port 6c. Further, if B ₅ or B ₄ size sheets are not used, the left large suction port 6a may be provided facing the end of the A ₄ or A ₃ size sheets. Fourth
The suction port 6 shown in the figure is not only B ₅ or B ₄ but also A ₄
This figure shows an embodiment in which a large suction port 6a is formed to be able to suck paper of A3 size or _A3 size at the same time.In short, the large suction port 6a is provided opposite to the vicinity of the edge of the paper for the purpose of preventing the paper from sagging. It is characterized by the provision of small suction ports 6b and 6c consisting of a large number of small openings. In addition, A ₃ or B ₄ is in the short direction,
B ₅ or A ₄ correspond to the longitudinal direction.

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

First, in FIG. 5, numeral 39 indicates a plurality of sheets stacked on a paper feed base plate 40 provided vertically in the direction of arrow C, 42 indicates a guide plate for the sheet paper being conveyed, Reference numeral 41 indicates a sheet conveying device in a standby state. In this device, a mode is set to change the suction force depending on whether the sheet to be conveyed is thin or thick. That is, the suction force control circuit 63 shown in FIG.
For example, in the case of a thin sheet of paper, the suction force of a blower or the like is reduced depending on the mode setting. Conversely, if the paper is a thick sheet, the suction force is increased.

Now, in FIG. 5a, when an instruction is given to start feeding sheet paper, the paper feed tray 40 moves the uppermost sheet paper 3 of the plural sheets 39 stacked thereon.
9' is the bottom surface of the sheet paper suction unit 5 and the pressure roller 1.
6 and rises along the direction of arrow C to a position where it is 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 section 5. That is, a suction blower (not shown) starts suctioning the sheet paper. At this time, if the stopping position of the paper feed base plate 40 has an error from the normal position, the error is corrected by the action of the flexible duct 3. That is, as shown in FIG. 1, the sheet paper suction section 5 is movable up and down by a maximum length l with respect to the suction air casing 1 by the flexible grip 3, and is rotatable within that range. Because of the structure, if the error is less than the length l, the uppermost sheet 39' will surely come into close contact with the air suction port 6 when air suction is started. Such behavior also occurs when the paper surface becomes uneven due to changes in environmental conditions, wrinkles, etc. In other words, the suction operation of the sheet paper is reliably performed by the start of air suction operation by the suction blower, and air inflow at the air suction port, which occurs when the adhesion is insufficient, that is, the suction force (negative pressure) decreases. can be completely prevented. Note that the sheet paper 37 at this time 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 61 shown in FIG.
The sheet paper suction unit 5 is rotated upward while gradually increasing its acceleration, and is stopped when it reaches a predetermined position, that is, a sheet transport position, as determined by a position detection means (not shown). By increasing 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 them. In addition, since the sheet paper suction unit 5 is gradually accelerated and raised, it is possible to suppress air from flowing in between the sheet paper 39' being sucked into the suction port 6, which may cause a decrease in suction force, etc. Prevents suction mistakes.

Here, since the suction port 6 of the sheet paper suction unit 5 is formed in the shape shown in FIG.
The small suction port 6b prevents the sheet paper 39' from sagging at the center, etc., so that the sheet paper 39' can be stably sucked, and air does not flow into the large suction port 6a, thereby preventing suction errors. In addition, since the suction force at the small suction port 6b is smaller than that at the large suction port 6a, the next sheet paper and the suction sheet paper 39'
This makes it easier for air to flow in between the two, making it possible to more reliably separate the two. In the suction port 6 shown in FIG. 4, if the sheet paper is B4 size or the like, air will flow in _from the small suction port 6c, causing _a decrease in the suction force. The suction force may be shielded by providing a shutter means or the like, or since the suction force of the small suction port 6c is weak, the suction force may be set large in the suction force control circuit 63 in anticipation of a decrease in the suction force due to the small suction port 6c. You can leave it as is.

Next, in the state shown in FIG. 5b, if the uppermost sheet paper 39' is not adsorbed to the bottom surface of the sheet paper adsorption unit 5, or if it is adsorbed with a large deviation, the sheet paper 39' shown in FIG. The adsorption detection circuit 62 detects this state. The sheet paper suction detection circuit 62 detects, for example, a change in the load current of a suction blower, and can thereby determine whether or not a sheet paper has been suctioned. In other words, if the load current decreases, it means that the sheet paper is attracted to the sheet paper suction unit 5. In addition to the above-mentioned detection, the suction section 5 may be provided with a micro switch or optical means for detecting whether or not a sheet is suctioned. If the sheet paper suction detection means 62 does not detect sheet paper suction or the like, the same operation as described above is repeated. This repeated operation is repeated a plurality of times, and if the sheet cannot be suctioned, the suction force is increased by the suction force control circuit 63 shown in FIG. 6, and the above operation is repeated again. If the suction is still not possible, all operations are immediately stopped and an alarm circuit (not shown) is activated.

In the state shown in FIG. 5b, the pressure roller 16 moves slightly in the direction of arrow G, but still presses the sheet 39 with a constant force. Therefore, when a plurality of sheets of paper are attracted, the stiffness of the paper becomes stronger due to the effect of the pressure applied by the pressure roller 16. Therefore, the pressing force overcomes the adsorption force between the sheets and causes the sheets below the adsorbed sheet to fall. The fallen sheet returns to its original position without shifting due to the pressure effect of the pressure roller 16.

Meanwhile, as above, the top sheet paper 3
If the suctioned sheet paper falls for some reason after the sheet paper 9' has been properly suctioned, the sheet paper suction detection circuit detects the fall, and the sheet paper suction detection circuit 5
Repeat the operations shown in Figures a and b.

When the uppermost sheet 39' is attracted as described above, the sheet transporting device 41 picks up the uppermost sheet 39' and starts transporting it in the direction of arrow H, as shown in FIG. 5c. When performing this conveyance, the suction operation and the pressure applied by the pressure roller 16 interfere with the conveyance, so the suction operation is stopped and the pressure roller 16 is pulled up in the G direction by the solenoid 25 (see FIG. 2). As a result, a smooth conveyance operation can be performed without damaging the paper under a low load condition.

By repeating the above-described operations shown in FIGS. 5a, b, and c, the stacked sheets can be sequentially conveyed. Note that the paper surface of the topmost sheet gradually decreases due to repeated conveyance, but until this drop in the paper surface of the top sheet reaches a certain state that requires replenishment, the flexible duct 3 will keep the paper surface low. This ensures that the sheet paper and the bottom surface of the sheet paper suction unit 5 can be attracted to each other.

According to the present invention, a large number of small suction openings made of small openings are provided between the large suction openings arranged near both ends of the sheet paper, so that the sheet paper can be stabilized without sagging. It can be reliably adsorbed in the same state. In particular, it is possible to prevent the occurrence of air inflow into the large suction port due to slackness, and to prevent suction errors that occur when suction failure occurs due to reduced suction.

In addition, the suction force of the small suction port to prevent sagging is smaller than the suction force of the large suction port that suctions the sheet paper, so the gap between the topmost sheet paper and the next sheet paper is This makes it easier for air to flow in, and the separation of the adsorption sheet and the next sheet becomes more reliable.

[Brief explanation of the drawing]

1 and 2 are side sectional views showing the sheet paper suction device of the present invention, FIG. 3 is a rear view showing substantially the entire sheet paper suction device, and FIG. 4 is a suction of the sheet paper suction device of the present invention. FIG. 5 is a bottom view showing a specific example of the mouth, FIG. 5 is a diagram for explaining the operation of the present invention, and FIG. 6 is an explanatory diagram of its operating circuit. 1: Suction air casing, 2: Negative pressure chamber, 3: Flexible duct, 5: Sheet paper adsorption section, 6: Air suction port, 6a: Large suction port, 6
b, 6c: Small suction port, 39: Sheet paper, 40:
Paper feed tray, 63: Suction force control circuit.

Claims (1)

[Claims] 1. A sheet of paper stacked on a paper feed tray is adsorbed by air suction from a suction port formed in a sheet paper adsorption section provided facing the paper. In the air suction type sheet paper suction device, the suction ports of the sheet paper suction unit provided facing the sheet paper have at least two large suction ports arranged corresponding to the vicinity of both ends of the sheet paper. and a large number of small suction ports arranged between at least the two large suction ports in order to suck the sheet-like paper sucked through the large suction port without sag. An air suction type sheet paper adsorption device featuring: