JPS594543A - Air suction type sheet material sucking device - Google Patents

Abstract

PURPOSE:To reduce a suction miss by a large margin in an sucking device applied to a paper feeder of a copier or the like by disposing a concave portion on a part of a paper feed table plate where stacked sheet materials are place, which is opposed to a sheet material sucking portion. CONSTITUTION:In a sucking device, with the base of a sheet sucking portion 5 brought into pressure contact with the uppermost sheet on a paper feed table plate 40, when a paper feed command is given, air is sucked from an air suction opening 6 to suck a sheet to the sucking portion 5. Subsequently, the device on the whole is turned clockwise on a contact point between a pressure roller and a sheet to lift up the sheet at the left end, so that the sheet is set at a clamping position to be clamped by a transport apparatus. In this arrangement, a recessed part 80 is formed on a part of the paper feed table plate 40, which is opposed to the sucking portion 5. Thus, the end portion of the sheet is deformed upward at the time of bringing the sucking portion 5 into pressure contact with the sheet so as to facilitate separating sheets individually.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for feeding sheet materials such as copying paper, transfer paper, reading paper, etc., and particularly to a device for feeding sheet materials such as copying paper, transfer paper, reading paper, etc. The present invention relates to an air suction type sheet material adsorption device that sucks air into the sheet material to be fed one by one.

Conventionally, in a device 46- which feeds sheets of paper or originals, etc. stacked on a paper feed plate one by one to a predetermined position,
It is common and widely used to provide a paper feed roller facing the stacked sheets and feed the sheets one by one by rotating the paper feed roller. A device using this paper feed roller feeds a single sheet using the q friction of the roller. Therefore, it easily damages the sheet material (original), it stains the front surface of the sheet material, it easily slips against art paper or coated paper, which has a low surface friction coefficient, and it also causes 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.

Therefore, in order to solve these drawbacks, various devices have been proposed that use air suction to adsorb sheet materials and convey the adsorbed sheet materials.

This device that uses air suction connects a sheet material 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 base plate to be collected. The uppermost sheet material of the sheet material is scooped up and placed on the bottom surface of the sheet material suction section, and the suctioned sheet material is conveyed.

However, the above-described sheet material suction device causes poor suction, especially when the sheet material has a strong inter-sheet adsorption force. That is, since the adsorption force between the sheet materials is strong, the resultant force when combined with the sheet material's own weight exceeds the suction force for adsorbing the sheet material, making it impossible to pull up the sheet material.

For this reason, a structure has been proposed in which a portion of the sheet material on the paper feed base plate is pressed by a sheet pressing member, and the leading end of the sheet material is pushed upward and folded.

However, in these conventional devices, the paper feed base plate is a rigid body, so when the number of sheets on the paper feed base plate becomes small,
There was a problem that the effect of pushing the tip of the sheet material upward could not be achieved.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, it is an object of the present invention to provide a sheet material suction device that enables reliable suction without causing suction failure.

In addition, the present invention provides: between the sheet material adsorption section and the sheet material;
It is an object of the present invention to provide a device that can perform a suction operation reliably even without precise placement.

In order to achieve the above object, the present invention provides an air suction type sheet material adsorption device that adsorbs sheet materials stacked on a paper feed base plate by air suction from a suction port formed in a sheet material adsorption section. '' - is configured such that a concave portion is provided in a part facing the sheet material suction section of the paper feed base plate, and with such a configuration, the present invention can provide the sheet material suction section with the edge of the sheet material suction section. Pressure is applied to the upper part of the sheet material in the four parts to push the sheet material in, and even when there are fewer sheets of originals on the paper feed base plate, the leading edge of the sheet can be separated and air can flow between each sheet material. By making it easier, the adhesion force between the sheet materials is weakened.

Further, according to the embodiment of the present invention, in order to reliably attract the sheet material, the suction operation is repeatedly performed in order to weaken the suction force between the sheet materials until the suction operation is suctioned.

Further, according to an embodiment of the present invention, the C)tel adsorption part is
When connecting to the negative pressure chamber, it is connected via a flexible duct to give the two suction parts a degree of freedom and to reliably pressurize the two sides of the sheet cage even if the distance from the sheet material is not uniform. This enables reliable adsorption.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The air suction type sheet suction device of the present invention 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 material suction device according to the present invention, FIG. 3 is a schematic perspective view of a paper feed plate, and FIG. 7 is a schematic view of the entire sheet material suction device. 5 is a bottom view showing an example of the suction port in the sheet material suction unit, FIG. 2 is an explanatory diagram for explaining the operation of the present invention, and FIG. 7 is a circuit related to the suction operation of unexploded r3J-1. FIG.

As shown in Figures 1 and 2, / in the figure is a suction air casing (referred to as a suction box on the outside) that is equipped with a negative pressure chamber inside. A sheet material suction section 5 having a plurality of air suction ports Z on the bottom surface is connected through 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/ and the inner surface of the side plate J-1 of the sheet material suction section j by fixing members. 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 extensible member whose length changes.

The sheet material suction part j is always pulled by a downward force by a tension member such as a spring. The tension member ♂ has one end fixed to the upper part of the U-shaped tension angle 2 and the other end fixed to the lower part of the U-shaped stopper angle 7. The tension angle 2 is fixed to a side plate J-1 forming the sheet material suction section S, and the stopper angle 7 has its upper part fixed to the air suction box. The other tension member ♂ has one end fixed to a slider 7'j that is slidably provided on the slide shaft, and is attached to a slider stopper 10 that restricts the slider 7'j from sliding to the lower limit of the slider 7'j. The ends are fixed. That is, due to the biasing force of both tension members ♂, the lower piece of the U-shaped tension angle 2 comes into contact with the lower piece of the stopper angle Z, the slider /, s, and the slider stopper 10, respectively (
The sheet suction part j is always pulled downward until the position 1γ (see the broken line diagram in FIG. 1). Note that one end of the slide shaft is fixed to one side plate of the upper air suction box.

Further, on the slider /j, a rotation angle /3 is rotatably supported on the rotation shaft /, 2 via a bearing // in the direction of the arrow, and the rotation angle /3 is attached to the seat. It is fixed to the side plate 6-1 of the material suction part j. Therefore, since the duct 3 can be deformed as shown by the solid line, the sheet material suction section 5 has a degree of freedom that allows it to move downward in the direction of arrow B within the length of the interval shown in the figure along the slide axis /g. are doing.

Further, the blue-absorbing portion j of the sheet material is rotated around the rotation axis /- within the range of .

In the figure, 0 indicates a paper feed base plate, and ♂0 indicates four parts provided on the paper feed base plate 0.

Next, referring to FIG. 1, the configuration of a pressure roller for pressing the uppermost sheet material will be described.

In the figure, 72 is a pressure roller. This pressure roller/2 is
It is rotatably provided around the M/ which is supported by the angle via a bearing/7. The angle ring 3 is fixed to the end of a downwardly movable slider 62 that passes through a bearing member 20 provided at the rear of the air suction box. One end of the slider, , 2/ is a rotating shaft, , 2. ? An engagement piece 2/a is provided with which one end of the arm 2.2 is engaged. Also, a rotation axis, 2. ? One end of the attached angle 23 engages with the latch 2 connected to the solenoid 2j. -The on/off operation of the above solenoids and 2j is as follows:
The slider 2/ is moved up and down within the range of the interval 0' via the latch 2z. When the solenoid 2J is on, the pressure roller 2 can move upward by .

From the arrangement described above, the pressure a-ra/ can be moved up and down by a distance 1' by means of the solenoid 26.

Further, in FIG. 3, a recess ♂0 is provided on the paper feed base plate ZO at a position facing a part of the sheet material suction portion j, and is provided over the entire width in the lateral direction so that the thin sheet material does not fall under its own weight.

Further, in FIG. 7, reference numeral 33 is a motor for driving, particularly rotating, the entire sheet material suction device. This motor 33 is attached to a motor attachment angle 3Z.

22 is a plywood board directly connected to the air suction box body, and a support member 30 integral with the drive shaft 3Z is attached to the lower part of this plywood board 22. The drive shaft 3z passes through a bearing portion of a bearing (not shown) provided on the support member 3/ fixed to the upper part of the motor mounting angle 3Z. Further, the rotational force from the motor 33 is transmitted to the drive shaft 3Z through engagement between a form 3 provided on the rotating shaft of the motor 33 and a form wheel 36 fixed to the drive shaft 3B. Incidentally, reference numeral 3 indicates a duct for connecting the suction blower (not shown) to the air suction box body.

The motor 33 is controlled and driven by a speed control circuit shown in FIG. The speed control circuit Z/ rotates the motor 33 and rotates the sheet material suction section j based on a rotation command signal after the sheet material suction section j performs the suction operation. Further, the speed control circuit 2/ controls the rotation of the motor 33 while gradually accelerating it, and gradually accelerates and raises the sheet material suction section S. Sheet material adsorption detection circuit 1.2 will be explained later
If no sheet material to be sucked is detected, the speed control circuit 2/ reverses the motor 33 based on this signal, returns the sheet material suction section j to its original position, and repeats the suction operation.

Next, referring to FIG. 5, the suction port 2 of the sheet material suction section j will be explained.

As shown in the figure, the suction ports 2 consist of a plurality of large suction ports 1a provided opposite to each other on the bottom surface of the sheet material suction unit j (near the edge of this paper size), and a plurality of small suction ports provided in between. It consists of a mouth and (b).It also has a large suction port 1a.
A plurality of small suction ports lc are further provided on the left side of the holder. This small suction port 1c is provided to suction not only B, s, or BF size sheet materials (including AF or A3 size sheet materials without sag. B(/ corresponds to the lateral direction, and Bj or AF corresponds to the longitudinal direction.

The suction force of the suction port 2 for sucking air is controlled by a suction force control circuit z3 shown in FIG.

The suction force control circuit z3 controls the suction force by controlling the rotation of a suction blower or the like, and controls the suction force through the air suction port 2 based on a suction command.

Further, when a sheet material non-detection signal is input to the sheet material suction detection circuit 2, a signal for repeating the suction process to perform the suction operation again is outputted.

At this time, the suction force control circuit z3 counts the non-detection signal using, for example, a counter, and when the counted value reaches a certain number, the suction force is strengthened and the suction operation is repeated.

Next, the operation of the air suction type sea material adsorption device of the present invention constructed as described above will be explained with reference to FIGS. 2 and 7.

First, in the figure, the reference numeral 32 indicates a large number of sheet materials stacked on the upper part of the paper feed plate 0, which is provided to be movable up and down in the direction of arrow C. A board is shown, and RI/ is a sheet material conveying device in a standby state.

In this device, mode settings are made to change the suction force depending on whether the sheet material to be conveyed is thin or thick. When the sheet material is thin, the suction force is set so as not to strongly suction many sheet materials at once, and when the sheet material is thick, the suction force is set to a suction force capable of adsorbing the sheet materials. That is, the seventh
The suction force control circuit g3 shown in the figure controls a suction blower and the like in order to make the suction force smaller in the case of a thin sheet material, for example, than in the case of a thick sheet material, depending on the mode setting. As a result, the suction force is weakened and the thin sheet material is sucked by the sheet material suction section j.

Now, in FIG. 2(a), when a signal indicating the start of transportation of the sheet material is output to the input device, the paper feed base plate 0 moves the uppermost sheet material 32 of the sheet materials 32 loaded thereon. ' has risen in the direction of arrow C to a position where it pushes up the bottom surface of the sheet material suction part j and the pressure roller/to some extent.

At this time, since the bottom edge of the sheet material suction part j is applied with a downward force by the tension member ♂, the upper part of the sheet material is pressurized and the sheet material 32 is pushed into the fourth part ♂0. This force pushes the leading end of the sheet material 32 upward and separates it. In this way, the bottom edge of the sheet material suction part j pushes the sheet material 32 into the four parts ♂0, so that even when there is only a small number of sheet materials on the paper feed base plate G0, the leading edge of the sheet material can be handled. Therefore, air can flow between each sheet material, and the adhesion force between sheets can be weakened. Such an operation makes it possible to peel off sheet materials one by one, which have a strong inter-sheet attraction force due to charging or the like, and to prevent mistakes in adsorption of one sheet or double feeding. Further, even if the sheet material is thin, the width of the recess 10 is small so that the powder mate material will not fall down due to its own weight. Furthermore, even if the sheet material is pushed into the four parts ♂θ by the above operation, the deformation is corrected by the elastic force of the sheet material, and no displacement occurs due to the pressing action of the pressure roller /g.

However, at this time, if the stopping position of the paper feed plate gu0 has an error from the normal position, it is corrected by the action of the flexible duct 3. That is, as shown in FIG. 1, the flexible duct 3 has a structure in which the sheet material suction part j can move up and down by the maximum length with respect to the air suction box body, and can also rotate within that range. Therefore, if the error is less than that length, the bottom edge of the sheet material adsorption section j will pressurize the sheet material 32.

Note that in this state, the sheet material 32 is in a state of being pressed by the pressure roller/g.

After the sheet material 32 is attracted in the manner described above, the operation shown in FIG. g (b) is then performed. This operation is to rotate the entire device in the direction of arrow E from the state shown in FIG. 4 (al).

This rotation is performed using the point of contact between the lower part of the V roller/2 and the uppermost sheet material 32' as a fulcrum while maintaining the suction operation.
This is done by driving the motor 33 (see Figure 3). In this case, the speed control circuit 1.2 increases the rotation of the sheet material suction section j while gradually accelerating it. That is, the speed control circuit 12 controls the speed of the motor 33 and gradually increases its rotational speed. The sheet material suction section j is stopped from rotating when it reaches a predetermined position, that is, a sheet material conveyance position, by a position detection means (not shown). At this time, the sheet material adsorption part j is as shown in FIG. 2(b).
It is held in the position shown.

By increasing the rotation while gradually increasing the acceleration in this manner, it becomes easier for air to flow between the uppermost sheet material 32' and the next sheet material, making it easier to separate the two. In addition, in order to gradually accelerate and raise the sheet material adsorption section 5,
It is possible to suppress air from flowing in between the sheet material 32' being sucked by the suction zero, and it is possible to prevent suction errors due to a decrease in suction force. That is, if the sheet material 32' that is being sucked is suddenly pulled up, the sheet material 32' will absorb
The force that tries to move away from E'' acts strongly, 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. 2 (1)), if the uppermost sheet material 32
' is not attracted to the suction port Z of the sheet material suction section j, the sheet material suction detection circuit 2- shown in FIG. 2 detects this. This sheet material suction detection circuit g detects the presence or absence of suction, and repeats the above-mentioned suction operation based on this. The circuit also detects, for example, a change in the load current of a suction blower, and thereby determines whether or not the seat member 32 is attracted to the suction port. For example, if the load current of the suction blower becomes large, it is detected that the sheet material is attracted to the attraction part j.

Instead of such a detection means, a microswitch or optical detection means may be provided in the sheet material suction section j to detect whether or not a sheet material is suctioned.

Therefore, if the sheet material adsorption detection circuit 1.2 does not detect the sheet material adsorption in the state shown in FIG. 2(b), (J
, if a detection signal is output), the same suction operation as described above is repeated. That is, if the non-detection signal is output, for example, the suction force control circuit z3 counts it and outputs a signal for repeating the suction operation to the speed control circuit g/. Therefore, the motor 33 is rotated in the reverse direction as shown in FIG. 2(a).
Return the sheet material suction part j to the position shown in l. Then, the suction force control circuit 3 suctions air again from the suction unit 2 to repeat the suction operation. The above-described suction operation is repeated, and if the sheet material 32 cannot be suctioned even after repeating this a certain number of times, the detection circuit Z, + outputs a non-detection signal to that effect. Based on this signal, the suction force control circuit z3 counts a certain number, increases the suction force, and instructs to repeat the suction operation again. The suction operation is repeated several times with this suction force strengthened, and if suction still cannot be achieved, the entire operation is immediately stopped. At the same time, the alarm circuit is activated to notify that suction is not possible.

Further, in the state shown in FIG. 2(b), the pressure roller /2 moves slightly in the direction of arrow G, but presses the sheet material 32 with a constant pressure. Therefore, when a plurality of sheets are attracted, the stiffness of the paper becomes stronger due to the pressure effect of the pressure roller/Z. Therefore, the pressing force of the pressure roller/g overcomes the adsorption force between the sheet materials, causing the sheet materials next to and below the adsorbed sheet material to fall. Then, the fallen sheet material returns to its original position (regular position) without shifting due to the pressure effect of the pressure roller/g.

On the other hand, if the suctioned sheet material falls for some reason after the uppermost sheet material 32' has been properly suctioned as described above, the falling sheet material is detected by the sheet material suction detection circuit
2 detects. As a result, Figure 2 (a) and (b)
) Repeat the operation.

In the sheet material suction s5, the sheet material is adsorbed by the air suction port 2, but from the shape of the air suction port shown in FIG.
is adsorbed by.

Therefore, the center portion of the adsorbed sheet material does not sag. In this figure 91, the size of the sheet material is AF
Or, in the case of A3, the minus side edge deviates from the large suction 0Δa, but since the small suction eye C is provided in that part, one side edge of the sheet material is also stably sucked without sagging. In addition, if the sheet material is BJ or BF size, the sheet material will not face the small suction port lc, but the total area of the suction port 1c should be calculated by taking into account the decrease in suction force due to air inflow from that part. The suction force is set so as not to fall below the suction force required to adsorb those sheet materials.

When the uppermost sheet material 32' is adsorbed as described above,
Next, the leading edge of the sheet material is caught by the sheet material conveying device Z/, and conveyance in the direction of arrow H is started as shown in FIG. 7(e). When performing this conveyance, suction operation and pressure roller/
The pressurization caused by No. 2 impedes transportation. Therefore, by stopping the suction operation and driving the solenoid 2J on the pressure roller, the pressure roller is pulled up in the G direction (see Figure 1).

As a result, the sheet material can be smoothly conveyed without being damaged under any load.

By repeating the above operations shown in FIG. is gradually decreasing.

However, even if the surface of the sheet material is lowered, the flexible duct 3 ensures close contact with the bottom surface of the sheet material adsorption section j.

As described above, according to the sheet material suction device of the present invention, the upper part of the sheet material is pressed into the recess on the paper feed base plate by the edge of the sheet material suction part, so that the sheet material is pushed into the recess on the paper feed base plate. Even when there are only a few sheets on top, the tips of the sheets can be separated, allowing air to flow between each sheet, weakening the suction force between the sheets, and preventing suction errors. It's large.

Furthermore, according to the embodiment of the present invention, the presence or absence of the sheet material sucked by the sheet material suction section is detected, and the suction operation is repeated based on this detection, especially non-detection, so that mistakes in sheet material suction can be avoided. It can be done very little. Also, if the suction operation is repeated multiple times and the suction operation is not successful, the air suction force is increased and the suction operation is repeated. Therefore, even if the suction force between the sheet materials is very strong,
The tip of the sheet material can be separated, and suction errors can be greatly reduced.

Further, according to the embodiment of the present invention, since the sheet material adsorption section is connected to the negative pressure chamber via a deformable or expandable duct, it is possible to constantly pressurize the sheet document at the edge of the sheet placement section. This can greatly contribute to preventing the above-mentioned suction errors.

[Brief explanation of the drawing]

1 and 2 are side sectional views showing a sheet material suction device according to the present invention, FIG. 3 is a schematic perspective view of a paper feed base plate according to the present invention, and FIG. 7 is a schematic diagram of a sheet material suction device according to the present invention. A rear view showing the whole, FIG. 5 is a sectional view showing an example of suction unit 1 of the sheet material adsorption device according to the present invention, and FIG. 7 <a),'
(b) and (C) are explanatory diagrams for explaining the operation of the present invention, and FIG. 7 is an explanatory diagram of the operating circuit in the present invention. /...Air suction box body (suction air casing)
, K... Negative pressure chamber, 3... Flexible duct, j
...S, Partial pouring part, 2...Air suction port, 33
...Motor, 32...Sheet material, Gθ...Paper feed plate, J/...Speed control circuit, JLz...
・Sheet, 1 stroke attachment detection circuit, z3... suction force control circuit, ♂θ... 4 parts.

Claims (1)

[Claims] 1. In an air suction type sheet material adsorption device that adsorbs the sheet material stacked on the paper feed base plate by air suction from the suction 1 formed in the sheet material suction unit, the sheet material on the paper feed base plate is An air suction type sheet material suction device characterized in that a concave portion is provided in a portion facing the suction portion.