JPH0115452B2 - - 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 that feeds sheet materials such as copy paper, transfer paper, and originals 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 the sheets one by one.

Conventionally, as a device for feeding sheet materials such as sheets of paper or manuscripts 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. It is common to feed sheet materials one by one by rotating the paper feed roller, and it is 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 material (manuscript), stains the surface of the sheet material, easily causes slipping on art paper or coated paper with a low surface friction coefficient, and 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 eliminate 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 automatic action of the sheet materials exceeds the suction force for adsorption of the sheet materials, making it impossible to pull up the sheet materials.

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, there is a problem that the effect of pushing the leading edge of the sheet material upward cannot be exerted. .

In view of the above-mentioned drawbacks, the present invention, in conjunction with the suction operation of the sheet materials, separates the leading edge of the sheet materials and flows air between each sheet material to weaken the suction force between the sheet materials. The purpose is to provide reliable sheet material adsorption without any defects. 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. The elastic member is provided at a position on the paper feed base plate that faces the bottom edge of the sheet material suction section except for a part in the sheet material conveyance direction, and with this structure, the present invention can be achieved. , when the number of sheet materials on the paper feed base plate is reduced by pressurizing the upper part of the sheet material with the sheet material sandwiched between the bottom edge of the sheet material adsorption section and the elastic member. However, the adhesion force between the sheet materials is weakened by separating the leading ends of the sheet materials and making it easier for air to flow between the sheet materials. Also, since a part of the bottom edge presses the normal paper feed base plate, there is no problem with air suction of the sheet material.

Furthermore, according to the embodiment of the present invention, in order to reliably attract the sheet material, the suction operation is repeated a plurality of times in order to weaken the adsorption force between the sheet materials until the sheet material is suctioned. 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 suction section is connected to the negative pressure chamber through a flexible duct, so that the suction section has a degree of freedom, and the spacing between the sheet material and the sheet material is not uniform. In both cases, reliable adsorption is possible by applying pressure to the top 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 suction 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 elastic member whose length changes.

The sheet material suction portion 5 is constantly pulled with 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 material suction section 5, and the stopper angle 7 has an upper portion fixed to the air suction box 1. The other tension member 8 is a slider 1 that is slidably provided on the slide shaft 14.
5, and the other end is fixed to a slider stopper 10 that restricts sliding of the slider 15 to the lower limit. That is, due to the biasing force of both tension members 8, the lower part of the U-shaped tension angle 9 always pushes the sheet material up to the contact position of the lower part of the stopper angle 7, the slider 15, and the slider stopper 10. The suction part 5 is pulled downward (see the broken line diagram in FIG. 1). In addition, the above slide shaft 14
One end 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-
It is fixed at 1. Therefore, the sheet material adsorption section 5
Since the duct 3 can be deformed as shown by the solid line,
It has a degree of freedom that allows it to move up and down in the direction of arrow B within a length range of the illustrated interval 1 along the slide shaft 14. 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 70 indicates an elastic member made of, for example, foamed rubber or foam-like resin, 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, the elastic member 70 is attached to the sheet feed base plate 40 at a position facing the sheet document suction unit 5 over 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 the figure, the suction ports 6 include a plurality of large suction ports 6a provided on the bottom surface of the sheet material suction unit 5 facing each other near the edge of the paper size, and a plurality of small suction ports 6b provided between them. It is made up of. Furthermore, a plurality of small suction ports 6c are further provided on the left side of the large suction port 6a. This small suction port 6c is provided to suction not only a _B5 or _B4 size sheet material but also an _A4 or _A3 size sheet material without sagging. 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 material non-detection signal is inputted 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 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.

Next, the operation of the air suction type sheet material adsorption 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, modes are set 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 suction a large number of sheet materials at once, and when the sheet material is thick, the suction force is set so as to be able to suction the sheet material. That is, the suction force control circuit 63 shown in FIG. 7 controls a suction blower or the like in the case of a thin sheet material, for example, in order to make the suction force smaller than that in the case of a thick sheet material, depending on the mode setting. 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. Arrow C until the bottom of the material adsorption section 5 and the pressure roller 16 are pushed up to some extent.
rising in the direction.

At this time, since the bottom edge of the sheet material adsorption section 5 is applied with a downward force by the tension member 8, the sheet material 39 is pressed between it and the elastic member 70 in a narrowed form. This force causes the elastic member 7 to
0 is deformed together with the sheet material, and the leading end of the sheet material 39 is pushed upward and separated. In this way, by applying pressure while sandwiching the sheet material between the bottom edge of the sheet material adsorption section 5 and the elastic member 70, even when the number of sheet materials 39 on the paper feed base plate 40 is small, , the leading edge of the sheet material can be separated, and therefore air can flow between each sheet material, thereby weakening the adhesion force between the sheet materials.

Through this operation, sheet materials that have strong inter-sheet adhesion due to static electricity etc. are peeled off one by one.
It is possible to prevent sheet material suction errors, double feeding, etc. However, at this time, if the paper feed base plate 40
If the stopping position of has an error from the normal position,
This is corrected by the action of the flexible duct 3. That is, as shown in FIG.
It can be moved up and down by a maximum length of l relative to the
Since the structure is rotatable within that range, the l
If the error is less than or equal to the length of , 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' being sucked is suddenly pulled up, a large force acts on the sheet material 39' to move it away from the suction port 6.
Air tends to flow in and suction errors occur frequently.
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 the speed control circuit 61
outputs a signal for repeating the adsorption operation. 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. 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 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, if multiple sheets are attracted, the pressure roller 16
The stiffness of the sheet material acts more strongly due to the pressurizing effect. Therefore, the pressing force of the pressure roller 16 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 (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 A ₄ or A ₃ , one end will be out of the large suction port 6a, but since a small suction port 6c is provided in that area, the sheet material will The side edges are also stably attracted without sagging. Also,
If the sheet material is _B5 or _B4 size, the sheet material will not face the small suction port 6c,
The total area of the suction ports 6c is set so as not to be less than the suction force necessary to adsorb those sheet materials, taking into account the decrease in suction force due to air flowing in from that part.

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. 6c. 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 bottom edge of the sheet material adsorption section 5 can always pressurize the sheet material due to the action of the flexible duct 3.

As described above, according to the sheet material suction device of the present invention, since the sheet material is pressed between the bottom edge of the sheet material suction section and the elastic member provided on the paper feed base plate, the sheet material The leading edge can be separated, air can flow in between each sheet material, weakening the adhesion force between the sheet materials, and a part of the bottom edge pressurizes the normal paper feed base plate, so the sheet material Since it does not affect air suction, it is highly effective in preventing suction errors.

Furthermore, according to the embodiment of the present invention, the presence or absence of the sheet material adsorbed by the sheet material adsorption section is detected, and the adsorption operation is repeated based on this detection, especially non-detection, so that the adsorption force between the sheet materials is reduced. Even if the pressure is very strong, the sheet material can be handled multiple times, and suction errors can be greatly reduced.

Furthermore, according to the embodiment of the present invention, since the sheet material suction section is connected to the negative pressure chamber via the deformable or expandable duct, it is possible to constantly pressurize the sheet material by the 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 paper adsorption section, 6... Air suction port, 33... Motor, 39... ...Sheet paper, 4
0...Paper feed base plate, 61...Speed control circuit, 62...Sheet paper adsorption detection circuit, 63...
...Suction force control circuit, 70...Elastic member.

Claims (1)

[Claims] 1 In an air suction type sheet material adsorption device that adsorbs sheet materials stacked on a paper feed base plate by suctioning air from a suction port formed in a sheet material adsorption section, the sheet material on the bottom edge of the sheet material adsorption section is An air suction type sheet material suction device, characterized in that an elastic member is provided at a position on the paper feed base plate, the portions of which are opposite to each other except for a portion on the conveying direction side.