JPS58139939A - Sheet multiple feed preventive device - Google Patents

Abstract

PURPOSE:To make multiple feeding surely preventable without any damage to a document, by using a document sheet suction preventive device provided with a rotor at a casing nose part making up a vacuum suction port, as a multiple feed preventive device. CONSTITUTION:A paper sheet feeder has a suction device 21 sucking a topper document sheet 25 of a sheet stack on a paper feeding table 32 vertically movable in a C direction. also the document sheet feeder has a document sheet multiple feed preventive device J being free of advance and retreat to act on the underside of a lifted document sheet 25 by vacuum suction and a feeding conveyor device 22 which holds the tip of the document sheet 25 separated piece by piece and sends it out. In this case, the multiple feed preventive device J forms an vacuum suction port 3 interconnected to a suction pressure chamber in a suction casing 1 at a part where a portion of the casing 1 is projected forward while an impeller type rotor 32 is installed at the tip lower part of the said part; this rotor is so constituted as to be rotated by air blown out of an air blast port 35.

Description

[Detailed Description of the Invention] This invention relates to a device for preventing double feeding of sheets,
In particular, the present invention relates to a sheet double-feed prevention device used in devices such as copying machines, electronic files, facsimile machines, printing presses, etc., which require reliability in the input mechanism for sheet originals.

Conventionally, various types of documents have been provided for separating and conveying a plurality of sheet documents stacked on a paper feed base plate one by one. For example, there is a method using corner separation claws, but this method is impossible to separate if the sheet original paper has a strong adhesion force, and it may also cause damage to the edges of the document. There are drawbacks. There is also a method of using a friction member such as a reversing roller, but with this method, delicate adjustments must be made as the thickness of the original sheet changes, and this adjustment may not be made or the adjustment may be inappropriate. In this case, there is a drawback that sheet i is likely to be fed multiple times. Furthermore, the above method has disadvantages in that the document may be soiled or damaged, and the separation ability may be reduced due to the presence of paper dust or the deterioration of the friction coefficient due to aging of the roller material. In addition, there is a method that uses a suction air box, rollers, belts, etc. in combination, but this method is useful when more than two sheet documents are being fed at once. It has many drawbacks, such as being able to separate only the originals, and easily damaging and staining the original, making it unsuitable for devices that require high reliability in the input mechanism for sheet originals, as mentioned above. It is.

The present invention has been made in view of the above, and instead of forcibly trying to prevent double feeding using a friction member as in the past, an air suction type is used and a casing that forms one suction unit. By using a sheet document suction prevention device for preventing double feeding, which has a rotating body attached to the tip of the sheet document, it is possible to reliably prevent multiple sheets of document documents from being conveyed at the same time without damaging the documents. The present invention aims to provide a highly reliable sheet electric transmission prevention device.

Hereinafter, one embodiment of the present invention will be described 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. 2 is a schematic side view thereof. The front view, Figure 3 is an enlarged perspective view of the suction 1-1 part and the rotating body, Figure 4 is
The figure is an explanatory diagram of the operation, Fig. 5 is an explanatory diagram of the effect of the rotating body, Figs. 6 and 7 are other examples of the rotating body, and Fig. 8 is an explanatory diagram of the operating circuit, and the same parts are shown in each drawing. are marked with the same symbol υ.

The sheet document feed prevention device of the present invention includes a sheet document suction device and a sheet document suction device for preventing double feeding. First, the characteristic sheet document suction device for preventing flj feeding 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 l. A negative pressure chamber 2 is formed inside the suction air casing 1, and a gauging l
Air suction [13
is formed.

An air outlet [13
5 is formed. Reference numeral 32 denotes a rotating body disposed at a position in front of the air blowing hole 35 at the bottom of the tip of the gauging 1, and this rotating body 32 has a plurality of blades arranged radially, and its central axis 34 is supported by a rotating body support member 33 attached to the lower surface of the casing l. As a result, this rotating body 32 blows air [135
It will be rotated by the air that is blown out.

Note that it is preferable to form the rotating body 32 using a material such as a soft rubber sheet or a flexible film-like sheet in order to prevent damage to the sheet original.

Further, a rotary shaft support plate 4 is attached to the lower part of the air gauge l, 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 driving base plate 7.

Therefore, the air casing l rotates llI
It rotates in the direction of the arrow A in the figure around b5, 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 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 slide shaft 9 and fixed to the drive base plate 7 via a motor mounting plate 14.

Figure 2 is a schematic diagram of the device seen from the front;
Suction air casing 1 indicated by arrow A in the figure
The rotational movement is achieved by connecting the launch angle 18 fixed to the lower part of the suction air casing l and the solenoid 16 attached to the solenoid mounting plate 17 by a latch 19, and by switching the solenoid 16 between ON and OFF. Let's do it. 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 8.

In FIG. 4, 21 is a sheet document suction device, 22 is a sheet conveyance device, 23 is a paper feed base plate provided to be movable in the direction of arrow C, and 24 is a document conveyance guide. ,
Reference numeral 25 indicates a plurality of sheet originals placed on the paper feed base plate 23, respectively.

"25' is the sheet original to be fed, that is, the uppermost sheet original among the sheet originals, and 25" is the sheet original next to the uppermost sheet original 25'.

In FIG. 4(a), when an instruction is given to start feeding sheet originals, the sheet feeding base plate 23 moves the uppermost sheet original 25' of the plurality of sheet originals 25 placed thereon. The document suction surface of the sheet document suction device 21 is removed along the arrow C direction until it touches the suction "-1". At this time, the sheet document suction device J for preventing double feeding is in the standby position shown by the solid line. There is no suction operation, and no air is blown out from the air outlet 35.

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

Next, the double-feed prevention sheet suction device J starts suction operation, and the air blowing from J35 also starts, and is stopped by the position control circuit shown in Fig. 8 at the slightly advanced position. Ru. This state will be explained in detail based on FIG.

In the figure, a plurality of sheet originals are pulled up by the sheet original suction device 21 due to static electricity, etc.
If the lower sheet document 40 naturally falls down due to the force of the paper's elasticity, etc., if the sheet document adsorption device J for preventing double feeding continues to move forward, the sheet document 40 that is coming down to the gauging tip will fall. There is a risk that the leading edge of Sheet 1 may be damaged due to contact with the leading edge of the original. However, as mentioned above, the sheet document suction device J for preventing vehicle transport is stopped,
At this position, air is blown out from the air outlet 35,
Using this as a power source, the rotating body 32 is rotated in the direction of the arrow R shown in FIG. 5, so that 1. (&ni-1-
This happens when the sheet original 40 falls as shown below. If the housing rotating body 32 is made of a material such as a soft rubber sheet or a flexible film-like sheet, the sheet original 4
0 damage can be more effectively prevented.

After performing the above operations, press the sheet suction device J for preventing double feeding.
further advances until the suction II comes into close contact with the back surface of the uppermost sheet document 25' that has been sucked by the sheet document suction device 21, at the position shown by the broken line in FIG. It retreats to a predetermined position shown by , that is, a sheet document suction detection position. The forward and backward movement of the sheet document suction device J for preventing transport is performed by a position control circuit shown in FIG. At this position, it is detected whether or not the sheet document is attracted to the suction port of the sheet document suction device J for preventing double feeding. A sheet document suction detection circuit that detects changes in the load current of the suction blower between when the document is suctioned and when it is not suctioned (see Figure 8)
It is done by

In this case, since the suction force (negative pressure) of the sheet document suction device J for preventing vehicle transport is set to be weaker than the suction force of the sheet document suction device 21, the sheet document suction device J for preventing vehicle transport is set to be weaker than the suction force of the sheet document suction device 21.
The sheet document suction device 21 does not pull down the uppermost sheet document sucked by the sheet document suction device 21. If the sheet document adsorption device J for preventing double feeding does not adsorb a sheet document, that is, if there is only one sheet in one sheet, as shown in FIG. 4(d).
As shown in FIG. 2, the tip of the casing l of the sheet document suction device J for preventing double feeding starts to press down the next and subsequent sheet documents.

On the other hand, when two or more sheet originals are being pulled up by the sheet original suction device 21, as shown in FIG. 25'' is attracted, and the uppermost original sheet 25' and the next original sheet 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. And the above state is the 8th
The sheet document suction detection circuit shown in FIG. After the predetermined time required for the document 25'' to fall and return to its original position has elapsed, the suction operation is restarted and a detection operation similar to that described above is started. Figure 4 (
If only two sheet originals are pulled up by the sheet original suction device 21 as shown in b), only one sheet original is suctioned by the sheet original suction device 21 in the same manner as above. After confirming the
) The operation moves on to the operation of pressing down the next or subsequent sheets of original.

If the number of sheet originals being picked up by the sheet original suction device 21 is more than two, the number of sheet originals sucked by the sheet original suction device 21 is reduced to one, as shown in FIG. 4(C). Repeat the same operation as above.

However, during the above operation, the sheet suction device J for preventing double feeding is placed at the sheet document suction position shown by the solid line T in FIG. However, because the suction force between paper sheets is extremely large, the sheet document suction device for preventing double feeding @J is in the standby position (
If the suctioned sheet document does not fall back to its original position even after returning to Figure 4 (a), repeat the above operation multiple times. In addition to increasing the suction force of the device J, the suction operation is not stopped even at the sheet document suction position, and the suction operation is continued for a certain period of time, that is, even while the sheet document suction device for preventing electrical transmission is retracted. If the next sheet document 25'' cannot be removed even after doing the above, all operations are stopped and a notification to that effect is sent.

As described above, the sheet document suctioned by the sheet document suction device 21 is transferred to the topmost sheet document 25 to be fed.
When only one sheet 25' is left, the sheet document conveying device 22 grabs the uppermost sheet document 25' and begins conveying it in the direction of the arrow E, as shown in FIGS. 4(c) and 4d. . At this time, the sheet document suction device J for preventing double feeding holds down the next sheet document at the lower end of its casing, and the topmost sheet from which the next sheet document is being conveyed. This prevents him from being carried along by Kyoto.

After the -1-most 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. 4(a). Then, the same operation as described in -1- is repeated for the next and subsequent sheet originals, and the sheet originals are sequentially conveyed.

According to the present invention, there is provided a double feeding prevention device that can reliably prevent the double feeding of various sheet materials including sheet originals without soiling or damaging the paper sheet. I can do it.

In addition to the above, examples of the rotating body in the present invention include the sixth
As shown in the figure, a roller made of a foam-like soft material 37 or a concave-convex roller made of a grooved elastic material 38 as shown in Fig. 7 can be used, and the driving source thereof is a motor limited to air. Of course, it is also possible to use the following.

[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, Fig. 2 is a schematic front view thereof, Fig. 3 is an enlarged perspective view of the suction port and the rotating body, and Fig. 4 is Operation diagram, 5th
The figure is an explanatory diagram of the effect of the rotating body, FIGS. 6 and 7 are sectional views showing other embodiments of the rotating body, and FIG. 8 is a diagram explaining the operating circuit. In the figure, 1 is the air casing, 2 is the negative pressure chamber, and 3 is the negative pressure chamber.
2 is an air suction port, 21 is a sheet document suction device, 22 is a sheet document transport device, 23 is a paper feed base plate, 24 is a document transport guide 25, 25', 25'', 40 is a sheet document, 32
3 is a rotating body, 33 is a rotating body support member, 34 is a central axis, 35
is air blower [1, J is sheet document suction device to prevent double feeding,
37 is a foam-like soft member, and 38 is a grooved elastic member. Hisashi Komori, Representative of Sharp Corporation, Patent Attorney, Figure 2, Figure 3, Figure 6, Figure 7

Claims (1)

[Claims] (1) A sheet original suction device having an air suction [ ], and a sheet original for preventing electrical transmission, which has an air suction 11 that moves the sheet original suction device to a position opposite to the suction surface of the original when the sheet original suction device is at a predetermined paper feeding position. a suction device, and when the sheet document suction device is at the predetermined paper feeding position,
Note: When multiple sheet originals are attracted to the sheet original suction device, the sheet originals following the first sheet original to be fed are sucked by the sheet original suction device for preventing double feeding. In the sheet double feeding prevention device, the sheet document double feeding prevention device is configured to perform the next operation such as feeding one liter of sheets when only one sheet document is peeled off by the operation and adsorbed by the sheet document suction device. Heavy feed prevention +I-, III A sheet electric feed prevention device characterized in that a rotating body is attached to the tip of a casing forming an air suction port of a sheet document suction device.