JPS62140950A - Device for preventing double feeding of sheet material - Google Patents

Abstract

PURPOSE:To prevent the double feeding of a sheet material by providing a means of separating a sheet material other than a sheet material which is directly brought into contact with the suction port of a sheet material adsorbing part. CONSTITUTION:When two sheet materials are drawn up at a time by a sheet material adsorbing device 21, the back face of a sheet material P'' in the following position to a sheet material P' to be conveyed in the topmost position, is pushed by a friction member 18 at a certain pressure. Since frictional force between a sheet material and the adsorbing device 21 and frictional force between a sheet material and the friction member 18, are made larger than adsorbing force between sheet materials, a gap S1 is produced between the sheet materials P' and P'' in a part in front of the part being pressed, and paper adsorbing force between the sheet materials P' P'' is weakened due to air flowing into the gap. the sheet materials P', P'' are also shifted S2 from each other at the rear of the pressed part, i.e., at the end part of the sheet materials, weakening a paper adsorbing force which acts on between the sheet materials P', P'', and the sheet material P'' is drawn to the sheet material back face adsorbing part 3 of a double feed preventing sheet material adsorbing device J.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention has an air suction port, and when a sheet material such as a document is at a predetermined paper feeding position, the sheet material is attracted to the sheet material, and the air suction port The present invention relates to a double feeding prevention device for sheet materials, which is provided in a sheet material suction unit that sucks the sheet materials, and prevents multiple sheets from being fed by suctioning them.

(Prior Art) Conventionally, when high reliability is required for the input mechanism of sheet materials in copying machines, electronic files, facsimile machines, printing machines, etc., various sheet material separation means, that is, stacking on paper feed base plates, have been used. Means for conveying a plurality of sheets of paper one by one has been used.

(Problems to be Solved by the Invention) Specifically, for example, there is a method using a corner separating claw. This is impossible to separate if the force acting between the sheet materials, ie, the so-called adhesion force between sheets, is large.

A further disadvantage is that damage may occur to the edges of the sheet material.

Also, reverse low-f-etc. 27. There is a method of using actual parts, but with this method, if the thickness of the sheet material changes, delicate adjustments must be made to match the change, and if this adjustment is not made or two circumferential alignment is appropriate, This has the disadvantage that sheet materials are more likely to be fed in duplicate. Furthermore, the sheet material may be soiled or damaged, and the separation ability may be reduced due to changes in the coefficient of friction caused by the presence of paper dust or changes in the roller material over time. There is also a method of using an air box together with rollers, belts, etc., but with this method, if more than two sheets are being fed at once, it is not possible to separate only the sheet material to be fed. Furthermore, it has many drawbacks, such as the sheet material being easily damaged and soiled, making it unsuitable for the above-mentioned apparatus in which the input mechanism of the sheet material is required to have high reliability.

Therefore, the sheet material adsorption section adsorbs the sheet material from the back surface of the adsorbed sheet material, and uses the physical suction force of the sheet material adsorption section to absorb the sheet material other than the sheet material that is directly adsorbed to the sheet material adsorption section. A sheet in which a continuous sheet material is peeled off one by one, so that the sheet material adsorption section finally adsorbs only one sheet material, thereby preventing double feeding of sheet materials. A device for preventing double feeding of materials is provided, but the frictional force between the sheet material adsorption section and the sheet material adsorbed by the sheet material adsorption section and the adsorption between the sheet material backside adsorption section and the sheet material adsorption section are If the frictional force between the sheet materials is not set larger than the adsorption force between the sheet materials,
When a plurality of sheet materials are attracted to the sheet material adsorption section at once, it becomes difficult to weaken the adsorption force between the adsorbed sheet materials. It had the disadvantage that it could not be separated.

Therefore, in the present invention, the sheet material adsorption section adsorbs the sheet material from the back side of the adsorbed sheet material, and physically suctions the sheet material other than the sheet material that is directly adsorbed to the sheet material adsorption section. The continuous adsorbed sheet materials are peeled off one by one by force, and finally the sheet material adsorption section is in a state where only one sheet material is adsorbed, and the sheet materials are multi-feeded. It is an object of the present invention to provide a device for preventing double feeding of sheet materials.

(Means for Solving the Problems) The present invention provides a sheet material adsorption section that adsorbs the sheet material by suctioning air from an air suction port when the sheet material is at a predetermined paper feeding position; means for moving the sheet material to a plurality of predetermined positions, and when the sheet material adsorbed by the sheet material adsorption section is at a predetermined back suction position, the sheet material is adsorbed by the sheet material adsorption section by suctioning air from an air suction port. a sheet material back surface adsorption section that adsorbs the sheet material back surface with a suction force smaller than the adsorption force of the sheet material adsorption section and larger than the adsorption force between the sheet materials, and the sheet material back surface adsorption section. means for moving to a plurality of predetermined positions, and when the sheet material adsorption section adsorbs a plurality of sheet materials, the sheet material other than the sheet material directly in contact with the suction port of the sheet material adsorption section is separated. It is equipped with the means.

(Function) The back side of the sheet material that has been adsorbed by the sheet material adsorption section is adsorbed by the sheet material back adsorption section, and the sheet material that has been adsorbed in succession to the sheet material that is directly adsorbed to the adsorption surface of the sheet material adsorption section is The sheets are separated one by one, and finally the sheet material suction section is brought into a state where only one sheet material is suctioned, thereby preventing double feeding of sheet materials.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view of a sheet material suction device for preventing double feeding according to the present invention, and FIG. 2 is a schematic plan view of the same device.

In FIGS. 1 and 2, J indicates the entire sheet material suction device for preventing double feeding, which has a suction air casing 1. Suction air casing 1
A negative pressure chamber is formed inside the suction air casing 1, and a part of the suction air casing 1 forms a sheet material back suction section 3 having an air suction port 14 projecting forward. A frame 5 that divides the air suction port 14 into two is formed in the center of the sheet material back suction portion 3 forming the air suction port 14, and a convex portion 50 having a friction member 18 is formed on the upper part of the frame 5. It is provided. This convex portion 50 as a whole fits into the sheet material suction port 46 facing the convex portion 50 if there is no sheet material between the sheet material suction device 21 and the sheet material suction device J for preventing double feeding. organized into shapes. Also, suction air casing 1
A negative pressure generation fan 30 for generating negative pressure inside the negative pressure chamber is attached to the side of the negative pressure chamber.

Further, the entire unit described above is configured to freely rotate in the direction indicated by arrow A in FIG. 1 by a drive device not shown. In the figure, numerals 32 and 33 indicate arms for rotating the double-feed prevention device attached to both sides of the suction air casing 1, 34° and 35 indicate a rotation boss and a rotation shaft, respectively, and the arm for rotating the double-feed prevention device 32.3
It is attached to the tip of 3. Further, reference numeral 60 in the figure indicates a double-feed prevention claw made of an elastic member, and as shown in FIG. It is attached to
The Porro rotating shaft 65 is moved to the first position by a pawl driving solenoid 70.
It is configured to rotate over a certain range in the direction of arrow 'bAH shown in the figure. When the pawl driving solenoid 70 does not operate, it is always stopped at a fixed position by a return spring 72 provided at the bottom of the double feed prevention pawl 60.

Next, the operation of the sheet material double feeding prevention device according to the present invention constructed as described above will be explained with reference to FIGS. 3 and 4.

In FIG. 3, reference numeral 21 denotes a sheet material suction device, 22 a sheet material conveyance device, 23 a sheet feeding plywood provided to be able to move up and down in the direction of the arrow "!aC, and 24 a document conveyance guide. , the reference numeral 41 indicates a pressure roller, the reference numeral 60 indicates a double-feed prevention claw, and the reference numeral P indicates a plurality of sheet materials stacked on the paper feed base plate 23.In addition, the reference numeral P' indicates a sheet material. Among them, the sheet material to be fed, that is, the uppermost sheet material, and the symbol P'' indicate the sheet material next to the uppermost sheet material P'.

First, in FIG. 3 (&), when the start of feeding of sheet materials is instructed, the sheet feeding base plate 23 selects the uppermost sheet material P' among the plurality of sheet materials P stacked thereon. It rises along the arrow C direction until it touches the suction port which is the sheet material suction surface of the suction device 21. At this time, the sheet material suction device J for preventing double feeding is in the standby position shown by the solid line, and no suction operation is performed. Further, since the pawl driving solenoid 70 is not operating, the double-feed prevention pawl 60 is in a position where it comes into contact with the end near the corner of the sheet material due to the movement of the return spring 72. In addition, the suction surface of the sheet material suction device 21 is swingable, so that even if there are variations in the stop position of the paper feed base plate 23 or variations in the thickness of the document, the uppermost sheet material P' is reliably placed on the sheet. The material is adsorbed by the material adsorption device 21.

Next, as shown in FIG. 4B, the sheet material suction device 21 rotates to a predetermined position, that is, the uppermost position, and then stops. At this time, a substantially constant pressure is applied to the sheet material by the pressure roller 41, and sheet materials having a small adhesion force between the sheet materials are separated by the elastic force of the sheet material itself. Further, since the force due to the elastic force of the sheet material itself depends on the angle at which the sheet material is bent, the sheet material is rotated to the uppermost position in order to increase its effect. Furthermore, the double-feed prevention claw 60 bends the edge of the sheet material near the corner to create a gap between the sheet materials, weakening the adhesion force between the sheet materials and increasing the effect of preventing electrical feeding. In the case of a strong sheet material, the sheet material will not be pulled down from the sheet material suction device 21 due to bending of the double feed prevention claw 60, which is an elastic member.

After the sheet material adsorption device 21 pulls up, the double feed prevention claw 60
is moved to a position where it does not come into contact with the sheet material for a certain period of time as shown by the broken line in FIG. It is designed to fall onto the paper feed base plate 23.

Then, after the double-feed prevention claw 60 returns, the double-feed prevention upper sheet material suction device J starts suction operation, and after rotating to a predetermined double-feed prevention position, the sheet material suction device 21 moves to the double-feed prevention position. Rotate [Figure (C)].

At this time, since the double-feed prevention pawl 60 has already returned to its original position as described above, even if the tip of the sheet material is curled, the tip is held down by the double-feed prevention pawl 60, and the double-feed prevention sheet There is no risk of contact with the tip of the material suction device J. Note that the sheet material suction device 21 is swingable, and after the back surface of the sheet material comes into contact with the sheet material suction device J for preventing double feeding, it moves in the direction of the arrow F depending on the relationship between the rotation direction and the suction surface. At this time, the pressure applied by the pressure roller 41 is released by a treinoid (not shown), and as shown in FIG. The back surface of the sheet material P'' next to the topmost sheet material P' to be removed is pressed with a constant pressure by the friction member 18. Also, the frictional force between the sheet material and the sheet material adsorption device 21 Since the friction force between the sheet material and the friction member 18 is made larger than the adhesion force between the sheet materials, the friction member 1 as shown in FIG.
8, a gap SI is created between the sheet materials P' and P'', and due to the inflow of air, the sheet materials P' and P''
At the same time, the adsorption force between the sheets is weakened, and a shift S2 also occurs at the rear of the pressed sheet material, that is, at the leading edge of the sheet material, and the adsorption force between the sheets acting between the sheet materials P'' and P'' is weakened, and the sheet material P '' is attracted to the sheet material back suction unit 3 of the sheet material adsorption device J for preventing double feeding.At this time, even if the force with which the friction member 18 is pressed against the back surface of the sheet material is very small, the effect is sufficient. is obtained.

Furthermore, even if the friction member 18 does not protrude from the sheet material adsorption surface as in this embodiment, or even if the friction member 18 is not positioned as in this embodiment, it is almost the same as long as it is on the sheet material adsorption surface of the device. It goes without saying that this effect can be obtained. Thereafter, in order to prevent the sheet material on the paper feed base plate 23 from shifting, pressure is applied by a pressure roller 41, and the sheet material suction device 2I is rotated to the uppermost position. This sheet material adsorption device 21
The rotation of the sheet material suction device J for preventing double feeding is performed by a position control circuit (not shown).

Then, at this position, it is detected whether or not the sheet material is attracted to the suction port of the sheet material suction device J for preventing double feeding.
This detection is performed by a detection unit 45 shown in FIG. In this case, since the suction force of the sheet material suction device J for preventing double feeding is weaker than the suction force of the sheet material suction device 21, the sheet material suction device J for preventing double feeding does not pull down the sheet material.

If no sheet material is adsorbed by the sheet material suction device J for preventing double feeding, that is, if there is only one sheet material, the sheet material suction device for preventing double feeding is used as shown in FIG. 3(d). J returns to the standby position indicated by the broken line.

On the other hand, when two or more sheets are being pulled up by the sheet material suction device 21, the suction port of the sheet material suction device J for preventing double feeding is used as the next one, as shown in Fig. 3'(d). The sheet material P'' is sucked, and the uppermost sheet material P' and the next sheet material P'' are separated by rotation of the sheet material suction device 21. Note that the suction force of the sheet material suction device J for preventing double feeding is set to be larger than the suction force between sheets. Then, the above-described state is detected by the detection unit 45, and the pressure roller 41 applies pressure so that the separated sheet material P# does not shift, and the double-feed prevention claw 60 is moved between the sheet materials by the claw driving solenoid 70. After moving to a position where there is no contact, the sheet material suction device J for preventing double feeding returns to the standby position shown by the broken line in Fig. 3(d), and the sheet material P'' falls and returns to its original position. After a predetermined time has elapsed, the same detection operation as described above is repeated until only one sheet material is left.

Even in the above manner, when the sheet material adsorbed by the sheet material suction device 21 is only the uppermost sheet material P' to be fed, the double feed prevention claw 60 first moves to the claw driving solenoid 70. After being moved to a position where it does not come into contact with the sheet material for a certain period of time, the sheet material suction device 21 is returned to its original position and simultaneously rotated to a predetermined position, that is, a gripping position, and pressure by the pressure roller 41 is applied. It is released by a solenoid (not shown), and the sheet material conveying device 22 grabs the uppermost sheet material P' and conveys it in the direction of the arrow E, as shown in FIGS. 3(Q) and (f). At this time, if there is a sheet material that falls naturally due to the elastic force of the sheet material itself, the sheet material that fell naturally due to the operation of the double-feed prevention claw 60 enters the underside of the double-feed prevention claw 60 and is held down. This prevents misalignment due to friction with the sheet material being fed. Then, the same operation as above is repeated for the next and subsequent sheet materials, and the sheet materials are sequentially conveyed.

In the embodiment described above, by making the suction surface of the sheet material suction device 21 swingable, the sheet material suction device 21
1 and the sheet material suction device J for preventing double feeding is widened, the design of the control section of the device is not only facilitated, but also the reliability of paper feeding can be improved.

In addition, a double-feed prevention claw 60 is provided, and in particular, the edge of a sheet material whose tip is curled upward comes into contact with a part of the sheet material suction device J for preventing double-feeding, thereby pushing the sheet material. There is no need to worry about misalignment, and the problem of misalignment of sheet materials following the sheet material to be fed due to friction with the sheet material to be fed is eliminated.

Note that the sheet material suction device J for preventing double feeding can be controlled to adsorb the sheet material by moving the sheet material suction device J for preventing double feeding, but as described above, the sheet material suction device 21 It is more preferable to move the sheet material on the paper feed mount 23 so that it does not shift. Furthermore, as a separation method when a plurality of sheet materials are attracted, after the sheet material suction device 21 moves to the back side suction position, the sheet material suction device J for preventing double feeding moves to separate the sheet materials. However, as described above, it is better to move the sheet material suction device 21 to separate the sheet material after the sheet material back suction section 3 has adsorbed the sheet material at the back suction position, which reduces the stiffness of the sheet material. This is more preferable because it allows for a longer distance to travel and also enables separation even when the adhesion force between the sheets, such as electrostatic force, is large.

(Effects of the Invention) As described above, according to the present invention, double feeding can be prevented very efficiently and reliably.

Furthermore, it becomes possible to utilize space efficiently, and therefore it is possible to provide a compact and highly reliable device.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of the sheet material suction device for preventing electrical transmission according to the present invention, Fig. 2 is a plan view thereof, and Fig. 3 fa) to ([1
4 is a schematic side view showing the separation state of sheet materials, and FIG. 5 is a schematic plan view showing a double feed prevention claw. 1... Suction air casing 3... Sheet material back suction part 5... Frame 14
...Air suction port 18...Friction member 2'1
... Sheet material adsorption device 22 ... Sheet material conveyance device 23 ... Paper feed base plate 3
0...Negative pressure generation fan 32.33...Double feed prevention device rotation arm 34...
Rotation boss 35... Rotation shaft 41... Pressure roller 45... Detection unit 50...
Convex portion 60...Double feed prevention claw 63...
Claw mounting block 65...Poro rotating shaft 70...Claw drive solenoid 72...Return spring P, P', P"...Sheet material J...Sheet material suction device fM7 for preventing double feeding Figure 4 Figure 5

Claims (1)

[Claims] 1) When the sheet material is at a predetermined paper feeding position, a sheet material adsorption section that adsorbs the sheet material by suctioning air from an air suction port; When the sheet material adsorbed by the sheet material adsorption section is at a predetermined back surface adsorption position, the sheet material adsorbed by the sheet material adsorption section is sucked by air suction from the air suction port. , a sheet material back suction section that sucks with a suction force smaller than the suction force of the sheet material suction section and larger than the adsorption force between the sheet materials, and means for moving the sheet material back surface suction section to a plurality of predetermined positions. and when the sheet material adsorption section adsorbs a plurality of sheet materials,
A device for preventing double feeding of sheet materials, comprising means for separating sheet materials other than the sheet materials directly in contact with the suction port of the sheet material suction section. 2) Frictional force between the sheet material adsorption section and the sheet material adsorbed by the sheet material adsorption section, and frictional force between the sheet material backside adsorption section and the sheet material adsorbed by the sheet material adsorption section. is made larger than the adsorption force between sheet materials, and when a plurality of sheet materials are adsorbed to the sheet material adsorption section, the sheet materials are shifted in relation to the frictional force to weaken the adsorption force between the sheet materials. A device for preventing double feeding of sheet materials according to claim 1. 3) The sheet material double feeding prevention device according to claim 1, further comprising a convex portion that partially pushes up the sheet material adsorbed on the sheet material adsorption surface of the sheet material adsorption section. 4) The device for preventing double feeding of sheet materials according to claim 3, wherein the convex portion has a shape that fits entirely into the suction port of the sheet material suction section. 5) The sheet material double feeding prevention device according to claim 1, wherein the sheet material adsorption section moves to three or more positions. 6) The apparatus for preventing double feeding of sheet materials according to claim 1, wherein the movement of the sheet material suction section is a rotational movement about a predetermined fulcrum. 7) The apparatus for preventing double feeding of sheet materials according to claim 1, wherein the movement of the sheet material back suction section is a rotational movement about a predetermined fulcrum. 8) The apparatus for preventing double feeding of sheet materials according to claim 1, further comprising a pressurizing means for pressurizing and pressing a portion of the sheet materials. 9) The sheet material double feeding prevention device according to claim 1, wherein the suction surface of the sheet material suction section is swingable. 10) Double feeding of sheet materials according to claim 1, wherein after the sheet material back suction section adsorbs the sheet material at the back suction position, the sheet material suction section moves to separate the sheet materials. Prevention device. 11) The double feeding prevention device for sheet materials according to claim 1, wherein the sheet material adsorption section moves to adsorb the sheet materials by the sheet material backside adsorption section. 12) The apparatus for preventing double feeding of sheet materials according to claim 1, further comprising a pressing member that presses an end of the sheet material at a specific position. 13) The sheet material according to claim 12, wherein the pressing member is pulled up by the sheet material adsorption section and has means for moving to a position where it does not contact the end of the sheet material located above the pressing member. Double feed prevention device. 14) The double feeding prevention device for sheet materials according to claim 12, wherein the pressing member is an elastic member. 15) The double feeding prevention device for sheet materials according to claim 12, wherein the specific position is near a corner of the sheet material.