JPS646093B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field This invention relates to a device for preventing double feeding of sheets, and is particularly applicable to sheet document input mechanisms such as copying machines, electronic files, fax machines, printing machines, etc. The present invention relates to a sheet double feeding prevention device used in devices that require high reliability.

(b) Prior Art and Problems to be Solved by the Invention Conventionally, various means have been provided for separating and conveying a plurality of sheet originals stacked on a paper feed plate one by one. For example, there is a method using corner separation claws, but this method has the disadvantage that it is impossible to separate sheets when the adhesion between the sheets is large, and damage may occur to the edges of the documents. . There is also a method of using a friction member such as a reversing roller, but with this method, if the thickness of the sheet document changes, delicate adjustments must be made to match the change, and this adjustment may not be made or the adjustment may be inappropriate. In some cases, there is a drawback that sheet originals are likely to be fed in duplicate. Furthermore, the above-mentioned method has disadvantages in that the document may be stained or damaged, and the separation ability is reduced due to changes in the coefficient of friction due to the presence of paper dust or changes in the roller material over time. There is also a method that uses a suction airbox in combination with rollers, belts, etc., but in this method, when more than two sheet documents are being fed at once, only the sheet documents to be fed are fed. It is not suitable for devices that require high reliability in the sheet document input mechanism as described above, as it has many drawbacks such as being unable to separate the documents and easily damaging and staining the document. be.

The present invention has been made in view of the above, and instead of forcibly preventing double feeding using a friction member as in the past, it uses an air suction system and a casing that forms the suction port. By using a sheet document suction prevention device with an air outlet at the tip to prevent double feeding, you can avoid damaging the document.
Moreover, it is an object of the present invention to provide a highly reliable sheet double feeding prevention device that can reliably prevent a plurality of sheet documents from being conveyed at the same time.

(c) Means for Solving the Problems The sheet double feeding prevention device of the present invention includes a sheet material suction device having an air suction port that suctions air from above and lifts the vicinity of the end of the stacked sheet materials; When the sheet material suction device is at a predetermined paper feeding position, the sheet material suction device is equipped with an air suction port for preventing double feeding, which suctions sheet materials below the topmost sheet material to be fed. In the double feeding prevention device for sheets, the sheet material adsorption device for preventing double feeding is configured such that when the sheet material adsorption device is lifting the sheet material,
A suction air casing is inserted between the loaded sheet material and the lifted sheet material, and an air outlet is provided in the insertion direction of the suction air casing,
It is characterized in that it is provided with an air suction port which is located above the air outlet and is formed of an inclined opening that comes into contact with the back surface of the sheet material being lifted up by the sheet material adsorption device.

(d) Effect In the sheet double feeding prevention device of the present invention,
The sheet material suction device uses the air suction port to suck the stacked sheet materials, and the sheet material suction device for preventing double feeding uses the air suction port to suck up the stacked sheet materials when the sheet material suction device is at a predetermined paper feeding position. The suction air casing installed in this sheet material suction device for preventing double feeding is equipped with an air outlet in the insertion direction to suck up sheet materials below the sheet material to be fed above. At the same time, an air suction port is provided above the air outlet and has an inclined opening that abuts the back surface of the sheet material being lifted by the sheet material suction device. Therefore, when the suction air casing is inserted between the sheet material being lifted up by the sheet material suction device and the sheet material being loaded, the sheet material is The material is moved upwardly or downwardly, and the casing tip does not come into direct contact with the edge of the sheet material.
Therefore, the sheet material will not be soiled or damaged. In addition, since the air suction port of the suction air casing comes into contact with the inclination of the sheet material being lifted by the sheet material suction device, the air suction port of the suction air casing comes into contact with the sheet material, so that the relatively weak air suction force is not applied to the sheet material. The next sheet material can then be pulled down.

(e) Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic side view of a sheet document suction device for preventing double feeding according to the present invention, and FIG. A schematic front view of the same, FIG. 3 is an enlarged perspective view of the suction port and air outlet, and FIG. 4 is an explanatory diagram of the operation.
FIG. 5 is an explanatory diagram of the effect of air blowing, and FIG. 6 is an explanatory diagram of the operating circuit. In each drawing, the same parts are given the same reference numerals.

The sheet double-feed prevention device of the present invention includes a sheet document suction device and a double-feed prevention sheet document suction device. First, the characteristic double-feed prevention sheet document suction device will be explained.

In FIGS. 1 and 4, J indicates the entire sheet document suction device for preventing double feeding, which has a suction air casing 1. As shown in FIG. A negative pressure chamber 2 is formed inside the suction air casing 1, and a portion of the casing 1 forms an air suction port 3 projecting forward. An air outlet 27 is provided at the lower end of the casing 1 forming the air suction port 3, and the air outlet 27 is connected to a fan (Fig. (not shown).

Further, a rotary shaft support plate 4 is attached to the lower part of the suction air casing 1, and a rotary shaft 5 is fixed to the rotary shaft support plate 4. The rotary shaft 5 is rotatably supported by a bearing member 6 such as a bearing provided on the drive base plate 7. Therefore,
The suction air casing 1 rotates in the direction of the arrow A in the figure around the rotating shaft 5, but the range of rotation is regulated by a stopper (not shown). The entire unit described above is designed to freely reciprocate in the direction of the arrow B in the figure, but this is because the slider 8 is fixed to the drive base plate 7, and the slider 8 is fixed to the slide shaft fixing plate 10. This is done by driving a motor 11 attached to the shaft 9 and fixed to the drive base plate 7 via the motor mounting plate 14.

FIG. 2 is a schematic diagram of the device seen from the front, and the rotational movement of the suction air casing 1 indicated by the arrow A in FIG. The angle 18 and the solenoid 16 attached to the solenoid mounting plate 17 are connected by a latch 19, and the solenoid 16 is turned on and off. Note that 15 is a gear for reciprocating the entire unit as indicated by arrow B in FIG. 1, and this gear 15 is attached to the gear mounting plate 13. Further, 20 is a duct connecting a suction blower (not shown) and the suction air casing 1.

Next, the operation of the sheet double feeding prevention device of this embodiment will be explained based on FIGS. 4, 5, and 6.

In FIG. 4, 21 is a sheet document suction device, 22 is a sheet document conveyance device, and 23 is an arrow C.
A paper feed base plate provided so as to be able to move up and down in the direction of 24
2 denotes a document conveyance guide, and 25 denotes a plurality of sheet documents placed on the paper feed base plate 23, respectively. Further, 25' indicates the sheet original to be fed, that is, the uppermost sheet original among the sheet originals, and 25'' represents the sheet original next to the uppermost sheet original 25'.

First, in FIG. 4a, when an instruction is given to start feeding sheet originals, the sheet feeding base plate 23 sucks the uppermost sheet original 25' of the plurality of sheet originals 25 placed thereon. The document rises in the direction of arrow C until it touches the suction port, which is the document suction surface of the device 21. At this time, the sheet document suction device J for preventing double feeding is in the standby position shown by the solid line, and no suction operation is performed. Also, air is not blown out from the air outlet 27.

Next, as shown in FIG.
5' is attracted by the sheet document suction device 21, and is raised to a predetermined position shown in the figure, that is, a paper feeding position, and then stopped.

Then, at the same time as the sheet document suction device J for preventing double feeding starts the suction operation, air is also started to be blown from the air outlet 27, and the air is sucked onto the back side of the top sheet document 25' that has been suctioned by the sheet document suction device 21. Move forward until their mouths are in close contact. Thereafter, it retreats to a predetermined position indicated by a solid line, that is, a sheet document suction detection position. The forward and backward movement of the sheet document adsorption device J for preventing double feeding is performed by a position control circuit shown in FIG. At this position, it is detected whether the sheet original is attracted to the suction port of the sheet document suction device J for preventing double feeding. This is performed by a sheet document suction detection circuit (see FIG. 6) that detects changes in the load current of the suction blower between when the sheet document is suctioned and when it is not suctioned. At this time, the air blowing operation from the air blowing outlet 27 is stopped before the suction port of the sheet document suction device for preventing double feeding comes into contact with the back surface of the sheet document 25' so as not to prevent the above-mentioned detection operation. In this case, since the suction force (negative pressure) of the sheet document suction device J for preventing double feeding is set to be weaker than the suction force of the sheet document suction device 21, the sheet document suction device J for preventing double feeding is The uppermost original sheet that is sucked by the suction device 21 is not pulled down. When the sheet original adsorption device J for preventing double feeding does not adsorb a sheet original, that is, when there is only one sheet original, the casing of the sheet original adsorption device J for preventing double feeding is shown in FIG. The first leading edge begins to press down the next and subsequent sheet originals.

On the other hand, when two or more sheet originals are pulled up by the sheet original suction device 21, the next sheet original is placed in the suction port of the sheet original suction device J for preventing double feeding, as shown in FIG. 4b. 25'' is attracted, and the uppermost sheet original 25' and the next sheet original 25'' are separated. Note that the suction force of the sheet document suction device J for preventing double feeding is set to be larger than the suction force between sheets. Then, the above state is detected by the sheet document suction detection circuit shown in FIG. 6, and the suction operation to make it easier for the sheet document 25'' to fall back to its original position is temporarily stopped.Then, as shown by the solid line in FIG. 4a, the suction operation is temporarily stopped. After returning to the standby position and after a predetermined time required for the sheet original 25'' to fall and return to its original position, the suction operation is started again, and air is blown out from the air outlet 27 to perform the same process as above. Enters detection operation. As shown in FIG. 4b, two sheet originals are pulled up by the sheet original suction device 21.
In the case of only one sheet, after confirming that there is only one sheet original adsorbed by the sheet original suction device 21 in the same manner as above, press the next sheet original as shown in FIG. 4d. Move on to the closing motion.

Further, if the number of sheet originals being pulled up by the sheet original suction device 21 is more than two,
The same operation as above is repeated as shown in FIG. 4c until the number of sheet originals adsorbed by the sheet original suction device 21 is one.

However, during the above operation, even though the sheet suction device J for preventing double feeding is in the sheet document suction position shown by the solid line in FIG. If the suction force between sheets is so large that the sheet document suction device J for preventing double feeding returns to the standby position (Fig. 4 a), the sheet document that was suctioned does not fall back to its original position. Repeat the above action multiple times.
If it still cannot be removed, the suction force of the sheet suction device J for preventing double feeding is increased, and the suction operation is not stopped even at the sheet document suction position, and the sheet document for preventing double feeding is continued for a certain period of time, that is, the sheet document The suction operation continues even while the suction device is retracted. Even after doing the above, if the next sheet document 25'' cannot be removed, all operations are stopped and a notification to that effect is sent.

As described above, when the number of sheet originals adsorbed by the sheet original suction device 21 is reduced to only one sheet, the uppermost sheet original 25' to be fed, as shown in FIGS. 4c and 4d, Sheet original conveyance device 22
engulfs the topmost sheet original 25' and moves to arrow E.
Start transporting in the direction. At this time, the double-feed prevention sheet document adsorption device J holds down the next and subsequent sheet documents at the lower end of its casing, and the next and subsequent sheet documents are held down by the topmost sheet document that is being conveyed. This prevents them from being transported together.

After the uppermost sheet document is conveyed, the sheet document suction device J for preventing double feeding returns to the standby position shown by the solid line in FIG. 4a. Then, the same operation as described above is repeated for the next and subsequent sheet originals, and the sheet originals are sequentially conveyed.

One embodiment of the present invention has been described above, but in the present invention, as described above, the air outlet 27 is provided at the tip of the casing forming the suction port to blow out air. Even if a sheet document falls from the sheet document suction device 21 above when the feed prevention sheet document suction device J moves forward from the standby position, or if there is a next sheet document that is extremely curled, the air blow The sheet original is moved upward or downward by the force of the air blown out from the outlet 27, so that the leading edge of the casing and the end of the sheet original do not come into direct contact as shown in FIG. 5a. Therefore, it is possible to prevent the sheet document from being soiled or damaged.

(f) Effects of the Invention As described above, the present invention provides a double feeding prevention device that can reliably prevent multiple feeding of various sheet materials including sheet originals without staining or damaging the originals. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a sheet document suction device for preventing double feeding according to the present invention, and FIG. 2 is a schematic front view thereof.
Figure 3 is an enlarged perspective view of the suction port and air outlet;
FIG. 4 is an explanatory diagram of the operation, FIG. 5 is an explanatory diagram of the effect of air blowing, and FIG. 6 is an explanatory diagram of the operating circuit. In the figure, 1 is a suction air casing, 2 is a negative pressure chamber, 3 is an air suction port, 21 is a sheet document suction device, 22 is a sheet document conveyance device, 23 is a paper feed base plate, 24 is a document conveyance guide, 25 ,25',2
5'' is a sheet document, 27 is an air outlet, 30 is a sheet document that has fallen from above, and J is a sheet document suction device for preventing double feeding.

Claims (1)

[Scope of Claims] 1. A sheet material suction device having an air suction port that sucks air from above to lift up the vicinity of the end of the stacked sheet materials, and when this sheet material suction device is at a predetermined paper feeding position, In a sheet double-feed prevention device comprising a double-feed prevention sheet material adsorption device having an air suction port that sucks sheet materials below the next highest sheet material to be fed, the double-feed prevention device comprises: When the sheet material adsorption device is lifting the sheet material, the sheet material adsorption device
A suction air casing is inserted between the loaded sheet material and the lifted sheet material, and an air outlet is provided in the insertion direction of the suction air casing,
An apparatus for preventing double feeding of sheets, comprising an air suction port formed of an inclined opening above the air outlet and abutting the back surface of the sheet material being lifted by the sheet material suction device.