JPH0419148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for feeding sheet materials such as copy paper, transfer paper, and original documents to be read, and particularly to a device for feeding sheet materials such as copy paper, transfer paper, and original documents to be read. The present invention relates to an air suction type sheet material suction device that suctions air to feed sheet materials in order to reliably feed sheets one by one.

Conventionally, as a device for feeding sheet-shaped paper or originals, etc. stacked on a paper feed base plate one by one to a predetermined position, a paper feed roller is provided facing the stacked sheet materials, and the It is common and widely used to feed sheets one by one by rotating a paper roller. A device using this paper feed roller feeds a single sheet by utilizing the friction of the roller. Therefore, the sheet material (manuscript) is easily damaged, the surface of the sheet material is stained, the surface friction coefficient is easy to slip on art paper or coated paper with a low surface friction coefficient, and the friction coefficient is 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 paper flow.

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

This device using 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 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. The uppermost sheet material of the sheet materials is suctioned by 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 decreases, even if pressure is applied by the sheet pressing member, the number of sheet materials decreases. Therefore, there was a problem in that the sheet material could hardly expand or contract, and the effect of pushing the leading end of the sheet material upward could not be exerted.

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.

Another object of the present invention is to provide an apparatus that can reliably perform a suction operation even if the interval between the sheet material suction section and the sheet material is not precisely arranged.

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. A recessed portion is provided in a portion of the paper feed base plate facing the sheet material suction portion, and with such a configuration, the present invention allows the sheet material suction portion edge to be provided in the recessed portion. Pressure is applied to the upper part of the sheet material to push the sheet material into a state, and even when the number of sheet documents on the paper feed base plate is small, the leading edge of the sheet material is handled to facilitate air flow between each sheet material. This is designed to weaken the adhesion force between the sheet materials.

Further, according to the embodiment of the present invention, in order to reliably attract the sheet materials, the suction operation is repeated in order to weaken the adsorption force between the sheet materials until the suction operation is completed. The suction operation is repeated based on a detection signal from a means for detecting suction of the sheet material.

Furthermore, according to the embodiment of the present invention, the sheet material adsorption section is connected via a flexible duct when connected to the negative pressure chamber, so that the adsorption section has a degree of freedom, and the distance between the sheet material and the sheet material is uniform. At the very least, reliable suction can be achieved by reliably pressurizing the upper surface of the sheet material.

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

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 base plate, and FIG. 4 is a schematic view of the entire sheet material suction device. FIG. 5 is a bottom view showing an example of the suction port in the sheet material suction unit, FIG. 6 is an explanatory diagram for explaining the operation of the present invention, and FIG. 7 is a circuit configuration diagram related to the suction operation of the present invention. It is.

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 material 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 connected to the inner surface of the air suction box body 1 and the inner surface of the side plate 5-1 of the sheet material adsorption section 5.
Each is fixed with a fixing member 4. 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 portion 5 is constantly pulled with downward force by tension members 8, 8a such as springs. 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 material suction part 5
The upper part of the stopper angle 7 is fixed to the air suction box 1. The other tension member 8, 8a is fixed at one end to a slider 15 that is slidably provided on the slide shaft 14.
Slider stopper 1 that restricts sliding to the lower limit of 5
The other end is fixed at 0. The biasing force of the tension member 8 causes the lower part of the U-shaped tension angle 9 to come into contact with the lower part of the stopper angle 7, and the biasing force of the tension member 8a causes the slider 15 and the slider stopper to come into contact with each other. The sheet material suction portion 5 is constantly pulled downward until it comes into contact with the sheet material suction portion 10 (see the broken line diagram in FIG. 1). Note that one end of the slide shaft 14 is connected to the upper air suction box body 1.
It is fixed to one side plate.

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. -1
is fixed. 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 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. There is. Further, the sheet material suction unit 5 is rotated within a range l around the rotation axis 12.

In the figure, reference numeral 40 indicates a paper feed base plate, and reference numeral 80 indicates a recess provided on the paper feed base plate 40.

Next, referring to FIG. 2, the construction of a pressure roller for pressing the uppermost sheet material 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 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, one end of the angle 23 attached to the rotating shaft 28 is engaged with a latch 26 connected to the solenoid 25. The on/off operation of the solenoid 25 is controlled by the slider 2 via a latch 26.
1 up and down within the interval l'. solenoid 2
5, the pressure roller 16 can move upward by l'.

With the arrangement described above, the pressure roller 16 can be moved up and down by the distance l' by means of the solenoid 25.

Further, in FIG. 3, a recess 80 is provided on the paper feed base plate 40 at a position facing a part of the sheet material suction section 5, and has a width b that prevents the thin sheet material from falling under its own weight, and is provided on the entire surface in the lateral direction.

Further, in FIG. 4, reference numeral 33 is a motor for driving, particularly rotating, the entire sheet material 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 a suction blower (not shown) and the air suction box body 1.

The motor 33 is controlled and driven by a speed control circuit 61 shown in FIG. After the sheet material suction section 5 performs the suction operation, the speed control circuit 61 rotates the motor 33 to rotate the sheet material suction section 5 based on a rotation command signal. Further, the speed control circuit 61 is
The rotation of the motor 33 is controlled while being gradually accelerated, and the sheet material suction section 5 is gradually accelerated and raised. Sheet material adsorption detection circuit 62, which will be explained further later
If no sheet material is detected, the speed control circuit 61 uses this signal to reverse the motor 33, return the sheet material suction section 5 to its original position, and repeat the suction operation.

Next, referring to FIG. 5, the suction port 6 of the sheet material suction section 5 will be explained.

As shown in FIG. 5, the suction ports 6 include a plurality of large suction ports 6a provided on the bottom surface of the sheet material suction unit 5 near the edge of the paper size, and facing each other.
It consists of a plurality of small suction ports 6b provided between them, and a plurality of small suction ports 6c 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 sheet materials but also A4 or A3 size sheet materials without sag. In addition, A3 or B4 is B5 or B4 in the short direction.
For A4, the longitudinal direction corresponds to each other.

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, and controls the suction force through the air suction port 6 based on a suction command. Further, when a sheet material non-detection signal is input from the sheet material 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 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 sheet material suction device of the present invention constructed as described above will be explained with reference to FIGS. 6 and 7.

First, in FIG. 6, reference numeral 39 indicates a large number of sheet materials stacked on the upper part of a paper feed base plate 40 that is provided to be movable up and down in the direction of arrow C, and 42 indicates a guide plate for the sheet materials being conveyed. 41 indicates 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. If the sheet material is thin, the suction force is set so that many sheet materials are not suctioned at once, and if the sheet material is thick, the suction force is set to be enough to attract the sheet materials. That is, the suction force control circuit 63 shown in FIG. 7, for example, in the case of a thin sheet material,
Depending on the mode setting, a suction blower or the like is controlled to reduce the suction force compared to the case of thick sheet material. As a result, the suction force is weakened, and the sheet material suction section 5 performs a suction operation on the thin sheet material.

Now, in FIG. 6a, when a signal instructing the start of sheet material feeding is output, the sheet feeding base plate 40 moves the uppermost sheet material 39' of the sheet materials 39 stacked thereon into a sheet. Move the arrow C until the bottom of the material adsorption section 5 and the pressure roller 16 are pushed up to a certain extent.
rising in the direction.

At this time, the bottom edge of the sheet material adsorption section 5 is applied with a downward force by the tension member 8, so that the upper part of the sheet material is pressurized and the sheet material 39 is pushed into the recess 80. This force pushes the leading end of the sheet material 39 upward and causes it to be separated. In this way, the sheet material adsorption section 5
By pushing the sheet material 39 into the recess 80, for example, even when there are only a small number of sheet materials on the paper feed base plate 40, the leading edge of the sheet material can be spread, and therefore air is created between each sheet material. can flow in and weaken the suction force between sheets. Such an operation makes it possible to peel off sheet materials one by one, which have a strong adhesion force between sheets due to charging, etc., one by one, and to prevent mistakes in adsorption and double feeding of sheet materials. Furthermore, even if the sheet material is thin, the width b of the recess 80 is small, so that the sheet material will not fall down due to its own weight.
Further, even if the sheet material is pushed into the recess 80 by the above-described 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 16.

However, at this time, if the stopping position of the paper feed base plate 40 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 allows the sheet material suction unit 5 to move up and down by a maximum length l with respect to the air suction box 1, and to rotate within that range. If the error is less than the length l, the bottom edge of the sheet material adsorption section 5 will pressurize the sheet material 39.

In this state, the sheet material 39 is under pressure by the pressure roller 16.

When the sheet material 39 is adsorbed as described above,
Subsequently, the operation shown in FIG. 6b is performed. This operation consists of rotating the entire device in the direction of arrow E from the state shown in FIG. 6a. This rotation rotates the lower part of the pressure roller 16 and the uppermost sheet material 3 while maintaining the suction action.
The motor 33 (fourth
(see figure). In this case, the speed control circuit 62 increases the rotation of the sheet material suction section 5 while gradually accelerating it. That is, the speed control circuit 62 controls the speed of the motor 33 and gradually increases its rotational speed. The rotation of the sheet material suction section 5 is stopped when the sheet material suction section 5 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 section 5 is held at the position shown in FIG. 6b.

By increasing the rotation while gradually increasing the acceleration in this manner, air can easily flow between the uppermost sheet material 39' and the next sheet material, making it easier to separate the two. Also, gradually the sheet material adsorption section 5
Since the sheet material 39' is accelerated and raised, air can be prevented from flowing between the sheet material 39' being sucked into the suction port 6, and suction errors due to a decrease in suction force can be prevented. That is, if the sheet material 39' that is being sucked is suddenly pulled up, a large force acts on the sheet material 39' to move it away from the suction port 6, making it easier for air to flow in, resulting in frequent suction errors. This is controlled by the speed control circuit.
This can be prevented by gradually accelerating.

Next, in the state shown in Figure 6b, if the topmost sheet material 3
If the sheet material suction port 9' is not suctioned by the suction port 6 of the sheet material suction section 5, a sheet material suction detection circuit 62 shown in FIG. 7 detects this. This sheet material 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 the sheet material 39 is attracted to the suction port 6 or not. For example, if the load current of the suction blower becomes large, it is detected that the sheet material is attracted to the attraction section 5.

Instead of such a detection means, a micro switch or optical detection means may be provided in the sheet material suction section 5 to detect whether or not a sheet material is suctioned.

Therefore, if the sheet material suction detection circuit 62 does not detect sheet material suction in the state shown in FIG. 6b (if it outputs a non-detection signal), 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 63 counts it and outputs a signal for repeating the suction operation to the speed control circuit 61. Therefore, the motor 33 is reversely rotated to return the sheet material suction section 5 to the position shown in FIG. 6a. 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 material 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 strengthened,
If it still cannot be picked up, stop all operations immediately. At the same time, the alarm circuit 64 is activated to notify that suction cannot be performed.

Further, in the state shown in FIG. 6b, the pressure roller 16 is
Although it moves slightly in the direction of arrow G, it is pressurized by the constant pressure of the sheet material 39. Therefore, when a plurality of sheets 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 of the pressure roller 16 overcomes the adsorption force between the sheet materials and causes the sheet materials next to and below the adsorbed sheet material to fall. Then, the fallen sheet material returns to its original position (normal position) without shifting due to the pressure effect of the pressure roller 16.

Meanwhile, as described above, the uppermost sheet material 39'
If the suctioned sheet material falls for some reason after being properly suctioned, the sheet material suction detection circuit 62 detects the fall. As a result, the operations shown in FIGS. 6a and 6b are repeated again.

Note that the sheet material suction unit 5 adsorbs the sheet material through the air suction port 6, and 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 Fig. 5, if the size of the sheet material is A4 or A3, one side edge will be out of place from the large suction port 6a, but since a small suction port 6c is provided in that area, one side edge of the sheet material will be removed from the large suction port 6a. The parts are stably adsorbed without sagging. Also
If the sheet material is B5 or B4 size, the sheet material will not face the small suction port 6c, but the total area of the suction port 6c is determined 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 level required to adsorb the sheet material.

As described above, when the uppermost sheet material 39' is suctioned, the sheet material conveying device 41 bites the leading end of the sheet material and transports it in the direction of arrow H as shown in FIG. 6e. 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 (see FIG. 2).
As a result, the sheet material can be smoothly conveyed without being damaged under any load.

By repeating the above-described operations shown in FIGS. 6a, b, and c, the stacked sheet materials can be sequentially conveyed. By repeating such conveyance, the surface of the uppermost sheet material gradually decreases. 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 5.

Since the air suction type sheet material suction device of the present invention is configured as described above, the sheet material is pressed against the recessed portion on the paper feed base plate by the bottom edge of the sheet material suction portion. Even when there are fewer sheets on the paper feed plate due to bending, the leading edge of the sheet can be folded, air can flow between each sheet, and the adsorption force between the sheets can be weakened. It can prevent suction mistakes.

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. In addition, 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, so 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 suction section is connected to the negative pressure chamber via a deformable or extensible duct, the sheet document can be constantly pressurized by the bottom edge of the sheet material suction section. This can greatly contribute to preventing the above-mentioned suction errors.

[Brief explanation of drawings]

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. 4 is a schematic diagram of a sheet material suction device according to the present invention. 5 is a sectional view showing a specific example of the suction port of the sheet material suction device according to the present invention; FIGS. 6 a, b, and c are explanatory views for explaining the operation of the present invention; FIG. 7 is an explanatory diagram of an operating circuit in the present invention. DESCRIPTION OF SYMBOLS 1... Air suction box body (suction air casing), 2... Negative pressure chamber, 3... Flexible duct, 5... Sheet material adsorption part, 6... Air suction port, 33... Motor, 39... ...Sheet material, 40...
... Paper feed base plate, 61 ... Speed control circuit, 62 ... Sheet material suction detection circuit, 63 ... Suction force control circuit, 8 ... Recessed portion.

Claims (1)

[Scope of Claims] 1. Raise the paper feed base plate and press the stacked sheet material against the sheet material adsorption section, and use the suction port formed in the sheet material adsorption section to adsorb and lift the sheet material. In an air suction type sheet material suction device that transports one end of the sheet material by pinching it with a sheet material conveying device, the sheet material suction section is attached to the sheet feeding base plate so as to be tiltable, and the sheet material A recess is provided on the upper surface of the paper feed base plate opposite to the bottom edge of the sheet material suction unit near the center of the material, so that when the sheet material on the paper supply base plate is pressed against the bottom face of the sheet material suction unit, this sheet The bottom edge of the material adsorption section and the recess provided in the paper feed base plate bend the sheet materials loaded on the paper feed base plate to eliminate adhesion between the sheet materials, and the adhesion detection means An air suction type sheet material adsorption device characterized in that the suction operation is repeated until adsorption of the sheet material is detected.