JPH1067442A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always blow air to a certain region where an uppermost sheet is positioned by providing nozzle position control means which moves the position of air nozzle placed to be movable when air is blown from the air nozzle to meet at least the position of the uppermost sheet. SOLUTION: When air blow operation of an air nozzle 2 is started, the position of an uppermost sheet P1 is detected by position detection means 3. Then, when detection information (position of sheet P1 ) of the means 3 is input to a main control part 41, the nozzle 2 is moved to the position of the sheet P1 (in the arrow direction) according to the control signal, whereby air is surely blown to a group of sheets including the uppermost sheet P1 and the uppermost sheet P and the other sheets not separated are surely separated. Accordingly, multi-feed of sheets can be prevented surely through the accurate separation of the uppermost sheet from the stacked sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus applied to an image forming apparatus such as a copying machine, a printer, and a printing machine. More particularly, the present invention relates to a sheet feeding apparatus which blows air onto a bundle of stacked sheets. The present invention relates to a sheet feeding apparatus for feeding sheets one by one while promoting separation.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a large number of various sheets such as copy sheets used for image formation are usually stacked on a paper feed tray, and the uppermost sheet of the stacked sheet bundle is stacked. Is provided with a sheet feeding device for feeding the sheets one by one into the apparatus in order from the sheet described in (1). In addition, a document (sheet) feeding device that automatically feeds a large number of documents to be copied to a reading unit to read the documents is provided.

In this type of sheet feeding apparatus, it is a major problem to eliminate a phenomenon that a plurality of sheets are overlapped and are simultaneously fed, that is, a so-called double feeding. As a feeding device, a function of installing an air nozzle mainly on the front side in the feeding direction of the stacked sheet bundle and injecting air between sheets by blowing air toward the sheet bundle from the air nozzle to separate There has been proposed a sheet feeding device provided with a sheet feeding device. A sheet feeding device having such a sheet separating function is mainly used in a suction feeding device (Vacuum Corrugetion Feeder; VCF) of a type in which a separated sheet is fed while being sucked to a suction conveyance belt or a roll. Have been.

In a conventional sheet feeding apparatus which blows air onto the sheet bundle to separate the sheets from each other, good sheet separation is performed in a certain range above the sheet bundle by blowing the air. Once the position is determined, the separation position does not fluctuate thereafter, so sometimes the most important top sheet is not separated from the second and subsequent sheets, and double feed occurs due to the unseparated sheet group. There is a problem that it will. For example, when the range of the 4th to 15th sheets from the top of the sheet bundle is the separation position, the range of the 1st to 3rd sheets deviating upward from the separation position is not separated thereafter, and The three sheets are conveyed in an overlapping state.

[0005] Such double feeding occurs because the air nozzles are fixed so that the air nozzles blow air to the upper position of the sheet bundle and separate the sheets at the upper position. Once the sheets are separated in a state where multiple sheets are stacked, the position of the sheet to be separated is transferred from the upper position of the sheet bundle to the position of the separated sheet, and air that promotes sheet separation is effective at that position Because it can no longer be sprayed.

As a countermeasure for eliminating the above-mentioned double feeding, for example, in the case of a VCF apparatus, a method of providing a convex portion along a sheet conveying direction at a predetermined portion of a sheet suction unit is conceivable. In other words, by blowing air to the suction portion provided with the convex portion, the upper layer sheet group separated in a state where a plurality of sheets are overlapped is once sucked so that only the uppermost sheet follows the convex shape. While the sheet is deformed by suction, the second and subsequent sheets are cut off by suction and at the same time, by the action of maintaining the flatness by the moderate strength of the sheet, the sheet follows the sheet as the top sheet. In this case, the uppermost sheet is separated from the uppermost sheet without deformation.

However, this countermeasure is effective when the sheet to be used is plain paper, but not effective for a thin sheet or a thick sheet. That is, since the thin sheet does not have the rigidity, the second and subsequent sheets are deformed along with the shape of the protruding portion together with the first sheet when adsorbed on the adsorbing section, so that a desired sheet is obtained. No separation occurs. On the other hand, a thick sheet is too stiff as opposed to a thin sheet, so that even the first sheet does not deform along the convex shape of the suction portion, and in this case, the desired separation can be achieved. Not done.

As another countermeasure for eliminating double feeding, there is a method in which the nozzle shape of the air nozzle is trapezoidal so that the opening area increases as it goes upward in the stacking direction of the sheet bundle. In this case, the opening area of the entire nozzle becomes large, so that an air compressor having a large capacity must be used, and there is a disadvantage that the sheet is excessively floated.

Further, in the above-described conventional sheet conveying apparatus, the magnitude of the adhesion between the sheets in the sheet bundle depends on the conditions of the sheets used (sheet surface material, paper basis weight, surface smoothness, etc.). Is greatly different, the sheet separation by air blowing may not be performed as the adhesion between the sheets increases, and there is a problem that the types of sheets that can be actually applied are limited to some extent.

In addition, such a problem will be solved in the future in color copiers and color printers by using highly smooth sheets such as art paper, coated paper, film and the like, similarly to printing machines. It is likely to become more apparent with new trends that we are trying to achieve. Particularly, in a high-temperature and high-humidity environment, sheets having high smoothness as described above have a very high sheet-to-sheet adhesion force compared to plain paper (when the adhesion of plain paper is 0.1 to 0.4 N, On the other hand, the high-smoothness sheets have an adhesion of 7 to 25 N), there is a possibility that multiple feeds may occur frequently, and the subsequent feeding may not be performed smoothly and a feeding error may occur. For this reason, there is a possibility that the conventional sheet feeding apparatus having the sheet separating function tends to be less adaptable to future diversification of sheets.

[0011]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to reduce the number of stacked sheets by blowing air from an air nozzle to the sheets to promote separation of the sheets.
An object of the present invention is to provide a sheet feeding apparatus capable of accurately separating the uppermost sheet of a stacked sheet bundle when feeding sheets one by one, thereby reliably preventing double feeding.

Another object of the present invention is to provide a sheet feeding apparatus capable of stably performing good sheet separation even when the kind and conditions of sheets to be used are different and sufficiently coping with the situation. To provide.

[0013]

According to the present invention, there is provided a sheet feeding apparatus which blows air from an air nozzle to a stack of stacked sheets to promote separation of the sheets, thereby reducing the number of sheets.
A device for feeding sheets one by one, wherein a position detecting means for detecting a position of a top sheet of the sheet bundle when air is blown from the air nozzle, and according to detection information of the position detecting means, A nozzle position control means for moving the air nozzle movably installed so as to at least match the position of the uppermost sheet with the position of the uppermost sheet is provided.

Here, the uppermost sheet of the sheet bundle refers to the sheet at the top of the stacked sheet bundle, and the first sheet has a plurality of second and subsequent sheets below it. This includes the case where they are in an overlapping state. The present invention is most effective particularly in a situation where the first sheet is separated and floated without being separated from the second and subsequent sheets when air for sheet separation is blown. .

Moving the position of the air nozzle so as to at least match the position of the uppermost sheet means that the air from the air nozzle is reliably blown to the position (range) where the first sheet exists. Adjusting the position of the air nozzle as described above. The air nozzle in the present invention basically blows air for separating (leaving) a sheet. However, in the case of an apparatus that uses an air nozzle for floating a separated sheet, the air nozzle is used. The present invention can be similarly applied to a floating air nozzle.

Further, according to the present invention, in the sheet feeding apparatus having the above-described configuration, the air nozzle of the sheet feeding apparatus is kept constant even when the distance between the sheet bundle and the end of the sheet bundle is different. It is provided movably.

Further, according to the present invention, in the sheet feeding apparatus having the above-described structure, the nozzle position control means moves the position of the air nozzle so as to follow the position of the uppermost sheet. The bundle is set so as to be moved along the stacking surface direction of the bundle or obliquely upward with respect to the stacking surface direction.

Further, according to the present invention, in the sheet feeding apparatus having the above-described structure, the air nozzle has a structure in which the nozzle diameter can be changed, and the air nozzle strength is adjusted by changing the nozzle diameter. It was done.

Further, according to the present invention, in the sheet feeding apparatus having the above-described structure, the air nozzle has a structure in which the direction of air blowing from the nozzle can be changed.

[0020]

Embodiments of the present invention will be described below.

FIGS. 1 to 3 show an embodiment of the present invention. The sheet feeding device in this embodiment is applied to a VCF device,
Air is blown against the sheet bundle P stacked and mounted thereon, and the air nozzle 2 movably provided. When the air nozzle 2 blows air, the sheet bundle P
Position detecting means 3 for detecting the position of the uppermost sheet P ₁ , and nozzle position controlling means 4 for controlling the position of the air nozzle 2 according to the detection information of the position detecting means 3.
And the suction conveyance belt 5 constitute a main part thereof.

The air nozzle 2 has a structure in which air of a constant pressure sent from an air compressor (not shown) through a pipe is blown out from a blowout port.
The outlet is directed toward the sheet bundle P.
In this example, the air nozzles 2 are arranged in pairs on the side of the sheet bundle P orthogonal to the sheet conveying direction X (see FIG. 1B). The initial position of the air nozzle 2 is a distance R from the rear of the suction conveyance belt 5 to the rear end of the sheet bundle P.
Is desirably arranged so as to be located at a position closer to the suction conveyance belt 5 from a half (central portion). The air nozzle 2 is installed by a known moving mechanism at least on the side surface of the sheet bundle P such that the air nozzle 2 can move in a direction perpendicular to the lamination surface (directions of arrows A and B). The air nozzle 2 has a horizontal (laminated surface) direction (arrow C and D directions) with respect to the lamination surface on the side surface of the sheet bundle P and a sheet bundle P in addition to the directions of arrows A and B as described later. May be installed so as to be able to move obliquely (in the directions of arrows E and F) with respect to the laminating surface direction on the side surface of. The air nozzle 2 may be arranged to blow air to the upstream (front) end of the sheet bundle P in the sheet conveying direction X or the downstream (rear) end of the sheet bundle P in the sheet conveying direction X.

The position detecting means 3 separates the sheet,
Not an obstacle during transport, said as long as it can detect the position of the sheet P ₁ at the top of the sheet stack P may be any one, there is no particular limitation on the type or the like. In this example, for example, as illustrated in FIG. 2, an optical detection unit including a laser light emitting element 30 and a light receiving element 31 that are provided upright to face the side surface of the sheet bundle P is used. This is because a plurality of laser beams LB are emitted from the laser light emitting element 30 at predetermined intervals in a direction perpendicular to the stacking surface of the sheet bundle P (directions of arrows A and B), and the laser beams are emitted from the laser beams LB. Are received by the light receiving element 31 and are identified.
When the sheet is displaced and crosses the laser beam, the position of the sheet is calculated by blocking the laser beam from entering the light receiving element 31. Further, the installation position of the position detecting means 3 is not particularly limited, but is preferably substantially the same as the position of the air nozzle 2. Further, the laser light emitting element 30 and the light receiving element 31 may be disposed inside the sheet end guide (6) as in the configuration of the air nozzle 2 illustrated in FIG.

As the position detecting means 3, in addition to the above-mentioned optical detecting means, for example, as shown in FIG. 5, a laser beam LB is irradiated on the sheet surface, the reflected light is received and the reflection time is measured. May be used as the optical detecting means including the laser displacement meter 32 which calculates the position of the sheet by measuring the position of the sheet. The laser displacement meter 32 can freely move above the sheet bundle P. FIG.
As shown in FIG. 2, a mechanical detecting means including a position detecting actuator 33 for calculating the position of the sheet from the amount of displacement by utilizing the fact that the contact piece abutting on the sheet surface is displaced following the displacement of the sheet is used. May be used.

Further, the nozzle position control means 4 comprises a drive control section 40 for controlling a moving mechanism for moving the air nozzle 2 in a predetermined direction and a main control section 41 for controlling the entire sheet feeding apparatus. Have been. The main control section 41 receives a detection signal of the position detection means 3 and outputs a control signal corresponding to the detection information to the drive control section 40. The drive control unit 40 moves the air nozzle 2 in a predetermined direction based on the control signal.
In this example, the nozzle position control means 4, so as to cause substantially coincide with the position of the sheet P ₁ at the top of the sheet bundle P is detected by the position detection unit 3, the air nozzle 2 to the laminated surface of the sheet bundle P It is set so as to move in a direction perpendicular to the direction (arrows A and B directions) (FIG. 1B).

The suction conveyance belt 5 in this example is stretched around a predetermined roll 50 and rotates. The conveyance belt 51 is provided with a number of suction holes, and is installed inside the conveyance belt 51. And a suction box 52 connected to the suction device by a pipe. Then, the uppermost sheet P1 sequentially separated from the sheet bundle P is sucked and adsorbed one by _one to the rotating transport belt 51 and fed to a predetermined portion or process.

The air nozzle 2 in this example is
As shown in FIG. 3, the separation distance s between the nozzle 2 and the end of the sheet bundle P is movably set so that the distance s is always constant even if the size of the sheet bundle P is different. Incidentally, the separation distance s between the nozzle 2 and the end of the sheet bundle P is 0 to 5 mm.
It is preferable to set to about. In the figure, reference numeral 6 denotes a sheet end guide which is attached to the tray 1 and has a structure which can be appropriately moved and fixed depending on the size of the sheet.

For example, when feeding a large-sized sheet bundle P0, the air nozzle 2 is installed so that the distance s from the end of the sheet bundle P0 becomes a predetermined value. Although good sheet separation can be performed by spraying to an appropriate portion, when feeding a small-sized sheet bundle P1, if the position of the air nozzle 2 is kept as described above and air is blown, the nozzle 2 and The distance L from the end of the sheet bundle P1 becomes long, and the air is scattered until the air reaches the end of the sheet bundle, so that good sheet separation is not performed. In this case, in order to compensate for the air that is dissipated due to the longer distance L between the nozzle 2 and the end of the sheet bundle P1, measures to increase the air blowing pressure of the air nozzle 2 or increase the amount of air blowing are also considered. However, such measures have a drawback that an air compressor with a large output is required, and it is difficult to control the sheet against high-pressure air blowing. Therefore, in this example, when the large size sheet bundle P0 is changed to the small size sheet bundle P1, the air nozzle 2
Is moved toward the end of the sheet bundle P1 like the sheet end guide 6, so that the distance s between the nozzle 2 and the end of the sheet bundle P1 becomes a predetermined value.

The movement of the air nozzle 2 performed when the size of the sheet bundle P is different is performed, for example, by providing a size change determining means for determining that the size of the sheet bundle P has been changed, and using the size information. Nozzle position control means 4
By moving the air nozzle 2. The size change determining means may be an input means for the user to input the size of the sheet bundle placed on the tray 1 or a means for detecting and determining the movement of the sheet end guide 6. .

The air nozzle 2 may be provided so as to be built into the sheet end guide 6 and integrated as shown in FIG. 7A. That is, the air nozzle 2 may be incorporated in the opening groove 60 provided at a predetermined portion of the sheet end guide 6 and may be arranged so that the air nozzle 2 can move along the opening groove 60. In such a case, the distance s between the air nozzle 2 and the end of the sheet bundle P can be kept constant only by moving the sheet end guide 6 when the size of the sheet bundle P is changed. Will be able to keep it. In this case, as shown in FIG. 7B, the air nozzle 2 is connected to a rack gear 61 to which the air nozzle is attached and the rack gear 61 to the opening groove 60.
It is necessary that the nozzle position can be appropriately changed by a moving mechanism including a gear 62 that meshes with the gear 62 and a drive motor 63 that rotationally drives the gear 62. Further, the opening groove 60 needs to have an opening structure that does not hinder the air blowing of the air nozzle 2 and that the blowing range is as wide as possible.

Next, the operation of the sheet feeding apparatus of this embodiment will be described.

When the sheet feeding device is started, air is blown from the air nozzle 2 toward the sheet bundle P placed on the tray 1. At this time, the air nozzle 2 is located in an upper layer portion (initial position) of the sheet bundle P before air blowing. Conventionally, since the air nozzle 2 was fixed, the upper layer of the sheet bundle P was separated and floated by the start of the blowing of the air.
(A), the then behavior that floating occurs in a state where the plurality of sheets of the sheet P ₁ and the second and subsequent uppermost (first) overlap without separation, which multifeed occurs It was one of the causes.

In this sheet feeding apparatus, when the air blowing by the air nozzle 2 is started, the position of the uppermost sheet P ₁ is detected by the position detecting means 3.
Position of the sheet P ₁ in this case, for example, from the top surface of the previous sheet bundle P blown air (flying) the height h is measured.

Information detected by the position detecting means 3 (sheet P
_When the position h) of ₁ is input to the main control unit 41, a control signal corresponding to the detection information is sent from the main control unit 41 to the motion control unit 41, and based on the control signal, the drive control unit 41
There by operating the moving mechanism, the air nozzle 2 is moved to the position h of the sheet P ₁ (moved in the arrow A direction). Position of the destination of the air nozzle 2 at this time, air blowing by the air nozzle 2 of the uppermost sheet P ₁
Any position can be used as long as the position can be reliably performed on a sheet group including

[0035] By air nozzle 2 as described above is moved, because the air is surely blown to the sheet group including the sheet P ₁ in the uppermost, as shown in FIG. 4 (b), until just sheet P ₁ the uppermost has not been separated from the sheet P ₂ of the second and subsequent, P _3, ··· it is reliably separated. The sheets separated in this manner are sucked and fed to the suction conveyance belt 5 in order from the top sheet.

While the sheet feeding by the sheet feeding apparatus is continued, the air blowing by the air nozzle 2 is always performed, and the position detecting means 3 continuously detects the position of the uppermost sheet. I have. Then, the position control of the air nozzle 2 by the nozzle position control means 4 according to the detection information is performed at any time. As a result, air blowing by the air nozzle 2 is always to be done to the sheet group including the sheet P ₁ the uppermost sheet separation by air blowing is carried out accurately and stably.

FIGS. 8 and 9 show another example of the embodiment of the present invention. That is, in the sheet feeding apparatus of this example, the nozzle position control means 4 causes the air nozzle 2 to be aligned with the position of the uppermost sheet so as to be perpendicular to the stacking surface of the sheet bundle P (arrows A and B). Direction), and the same configuration as that of the above-described embodiment except that the sheet bundle P is also set to move in the direction of the stacking surface of the sheet bundle P (directions of arrows C and D).

That is, as shown in FIG. 8, the nozzle position control means 4 in the present embodiment moves the position of the air nozzle 2 based on the detection information of the position detection means 3 in a direction perpendicular to the stacking surface of the sheet bundle P (arrow). after adjusting the position of the sheet P ₁ at the top is moved in the a direction), as shown in FIG. 9, while the sheet bundle in a state where combined the air nozzle 2 to the position of the sheet P ₁ in the top level P stacking surface direction (arrows C and D
Direction). In this case, the movement of the sheet bundle P in the stacking surface direction is simply performed in the sheet conveying direction X.
May be moved by a predetermined amount in the opposite direction (the direction of arrow C), or may be moved so as to reciprocate in the sheet conveying direction X and the opposite direction.

By moving the air nozzle 2 in this manner, even if the sheet feeding speed is increased,
It is possible to reliably perform sheet separation, and it is possible to sufficiently cope with the problem. That is, when sheet feeding is faster, because the time between feeding the sheet separation and sheet is shortened, air blown by a sheet of a portion in the air is to the sheet P ₁ in the uppermost accurate segregation pass Even if it starts to be
The possibility that the feeding operation by the suction conveyance belt 5 (the operation in which the leading end side in the sheet conveyance direction is sucked and conveyed by the suction conveyance belt 5) is started before the entire sheet is completely separated increases, As a result, the entire sheet is not completely separated by the adhesive force of the sheet part that does not separate (for example, the sheet P2 part in FIG. 8), and double feed or misfeed is likely to occur. In this regard, by moving the air nozzle 2 also in the direction of the stacking surface of the sheet bundle P (the direction of arrows C and D) as in the apparatus of the present example, air is efficiently blown over a wider range between the sheets, and Since the separation is performed in a short time (see FIG. 9), as a result, the double feed as described above is prevented, and the speed of the apparatus can be increased.

FIGS. 10 and 11 show another example of the embodiment of the present invention. That is, in the sheet feeding apparatus of this example, the nozzle position control means 4 adjusts the position of the air nozzle 2 to the position of the uppermost sheet.
After moving in the direction (arrows A and B) perpendicular to the stacking plane of the sheet bundle P, the sheet bundle P is also set to move diagonally (directions of arrows E and F) with respect to the stacking plane of the sheet bundle P. Except for this, the configuration is the same as that of the embodiment.

In other words, as shown in FIG. 10, the nozzle position control means 4 in this embodiment sets the position of the air nozzle 2 based on the detection information of the position detection means 3 in the direction perpendicular to the stacking surface of the sheet bundle P (arrow). (A direction) to adjust the position of the uppermost sheet P ₁ , and then, as shown in FIG. 11, the air nozzle 2 is inclined at a predetermined angle with respect to the lamination surface direction of the sheet bundle P. (Directions of arrows E and F). In this case, the movement of the sheet bundle P in the stacking surface direction may be simply performed by moving the sheet bundle P by a predetermined amount so as to gradually increase in the direction opposite to the sheet conveying direction X (the direction of arrow E). By moving the air nozzle 2 in this manner, even when the sheet feeding speed is increased, it is possible to perform the sheet separation reliably, as in the above-described example, and therefore, it is necessary to take sufficient measures. Can be.
Further, in this case, the moving distance L _{2 of the} air nozzle ₂
But it is possible to perform the movement distance reliable sheet separation with an amount less than L ₁ of the air nozzle 2 when moving in the horizontal direction, it becomes possible to cope with feed more accelerated sheet.

The air nozzle 2 is shown in FIG.
As illustrated in FIG. 13 and FIG. 13, the nozzle diameter r may be configured to be changeable, and the air blowing intensity may be adjusted by changing the nozzle diameter r. In this case, the air flow rate of the air supply source may be kept constant. That is, when the nozzle diameter r is set to be relatively large, the blowout intensity can be reduced, and when the nozzle diameter r is set to be small, the blowout intensity can be increased.

The nozzle illustrated in FIG.
0 is provided with the same mechanism as the lens shutter of the camera, and a plurality of shutter blades 21 arranged to move concentrically in a point symmetry with the center point of the nozzle port 20 are displaced in a predetermined direction to open and close. By doing so, the hole diameter r of the circular hole 22 formed at the center is adjusted (FIGS. A and b). On the other hand, the nozzle illustrated in FIG. 13 is formed at the center thereof by displacing in a predetermined direction four movable plates 23 that are disposed in the nozzle port 20 so as to be capable of being formed into rectangular pieces. The hole diameter r of the rectangular hole 24 is adjusted (FIGS. 7A and 7B).

Conventionally, the adjustment of the air blowing intensity is performed by opening and closing a valve arranged in the middle of a pipe duct connecting the air nozzle and the air compressor, or by adjusting the output of the compressor itself. However, all of these methods had to use a compressor with a large capacity and could not be finely adjusted. In this regard, as described above, by keeping the air flow rate constant and changing the nozzle diameter r, it is possible to finely adjust the air blowing intensity, and it is not necessary to increase the capacity of the compressor and to reduce the capacity. It has the advantage that it can be used with any compressor. Moreover, by finely adjusting the air blowing intensity,
Even when separating sheets having different sheet-to-sheet adhesion forces, sheet separation can be reliably performed.Also, even if the speed of the apparatus is increased, the sheet separation speed can be increased by slightly increasing the blowing strength, Further, the floating state of the separated and levitated sheet can be adjusted.

When the air nozzle 2 having the nozzle structure as illustrated in FIG. 13 is used, four movable plates 2 are used.
The position of the nozzle hole 20 can be moved up and down as shown in FIG. 14 by adjusting the manner of movement of the nozzle hole 3 (a in FIG. 14), or the position of the nozzle hole 20 can be moved up and down in the horizontal direction. (B in the same figure), or the nozzle hole 20 can be moved in an oblique direction (for example, the directions of arrows E and F).

The air nozzle 2 is shown in FIG.
As illustrated in FIGS. 18 to 18, a structure in which the air blowing direction (angle) can be changed may be employed. The nozzle 2 illustrated in FIG. 15 has a wind direction plate 26 that swings along the stacking surface direction of the sheet bundle P around the support shaft 25 at the nozzle tip, and the nozzle 2 illustrated in FIG. Has a wind direction plate 28 that swings along the direction perpendicular to the direction of the stacking surface of the sheet bundle P around the support shaft 27 at the tip of the nozzle. The nozzle 2 shown in FIG. 17 is attached to the eccentric cam plate 70 in a state where the air nozzle (tube) 2 is inclined with respect to the rotation axis G, and the eccentric cam plate 70 is rotated to form the air nozzle (tube). The air blowing direction can be changed depending on the position (2) (a and b in the figure). In this case, the blowing direction can be changed to various angles, and at the same time, the blowing position can be changed. Further, the nozzle 2 illustrated in FIG.
Are simultaneously brought into contact with the outer peripheral surfaces of two eccentric cam plates 71 and 72 having different rotation axes, and follow the movements of the respective outer peripheral surfaces. The direction of the balloon can be changed.

With the structure in which the air blowing direction of the air nozzle 2 can be changed in this manner, the blowing direction is set in the direction of the stacking surface of the sheet bundle P (the directions of arrows C and D) as shown in FIG. In the case of a change, the sheet portion P3 into which the air is blown spreads over the entire surface of the sheet in a short time, and the sheet separation can be performed more reliably in a short time. Can be. P2 indicates a sheet portion to which air has not yet been blown (that is, not separated). In addition, as shown in FIG. 20, when the blowing direction is changed to a direction (arrows A and B directions) orthogonal to the stacking surface of the sheet bundle P, the floating state of the separated and floating sheet P4 is adjusted. be able to.

Further, as for the tray 1 of the sheet feeding apparatus, as shown in FIG. 21, a groove 11 for guiding the flow of air may be provided on an edge of the tray bottom plate 10 which falls within the movable range of the air nozzle 2. By providing such a groove 11, even if the remaining amount of the sheet bundle P on the tray bottom plate 10 is reduced, the air blown from the nozzle 2 enters the lower side of the lowermost sheet. By adjusting the position of the air nozzle 2 so that the end portion of the sheet P floats and aligns with the position of the uppermost sheet of the sheet bundle at that time, even the sheet bundle with a small remaining amount is shifted from the uppermost sheet by one. It is possible to reliably separate sheets one by one.

The sheet feeding apparatus according to the present invention is not limited to the above-described one employing the suction type conveyance (VCF) apparatus.
For example, the present invention can be applied to a case where a friction type sheet feeding device 8 as illustrated in FIG. 22 is employed. The friction type sheet feeding device 8 illustrated in FIG. 22 includes a delivery roll 80 that is provided so as to be able to contact and separate from the upper surface of the stacked sheet bundle P placed on the tray 1.
A friction pad 81 fixedly disposed on the downstream side in the sheet conveyance direction X of the delivery roll 80, and a separation roll 82 that rotates while sliding on the friction pad 82 (Fr).
iction Retard Pad Feeder; FRPF). Basically, the friction-type sheet feeding device includes a sheet group (1) of an upper layer in a state where the delivery roll 80 is in contact with the upper surface of the sheet bundle P.
When the sheet group is sent to a position just before the separation roller 82, the sheet group comes into contact with the friction pad 82 and stops, and only the uppermost sheet of the sheet group is separated and sent out by the separation roller 82. ing. The friction type sheet feeding device may be of a type other than the above type. For example, in place of the friction pad, a type in which a hard-to-rotate friction roll is disposed (FRPF) or a type in which a special roll that rotates in a forward / reverse direction in small increments like a pendulum motion (ARRF) are used. Is also good.

[0050] In the case of this friction sheet feeder 8 feed adopted sheet the device, the roll 80 sheet P ₁ the uppermost feed in friction paper feeding device 8 side of the sheet bundle P (sheet conveying direction leading side) since that is a held down state by like, differ from its position of the sheet P ₁ is that it does not particularly changed, the VCF device feeding adopted sheet device. For this reason, when the rear side of the sheet is not sufficiently separated by blowing air, double feeding tends to occur.

Therefore, in a sheet feeding apparatus employing such a friction type sheet feeding apparatus 8, it is important how to set the position of the air nozzle 2 to achieve reliable sheet separation. The air nozzle 2 basically has a position detecting means 3
Sheet P _{1 at} the top of the sheet bundle P detected by
Is moved to a predetermined position by the nozzle position control means 4 in accordance with the position of the uppermost sheet P ₁ located on the rear side of the friction-type sheet feeding device 8. To move the air nozzle 2. Since the friction position of the sheet P ₁ at the top of the sheet feeding device 8 near hardly changes, if you set the initial position of the air nozzle 2 to 8 near friction sheet feeder, moves the nozzle 2 Few things.

For example, the air nozzle 2 moves in a direction (directions of arrows A and B) orthogonal to the stacking surface of the sheet bundle P so as to match the position (height) of the upper-side sheet group that has floated and been separated by the air blowing. After the movement, the sheet bundle may be moved rearward (in the direction of arrow C) along the stacking surface of the sheet bundle (see FIG. 9). After moving in the direction (arrows A and B) perpendicular to the stacking surface of the sheet bundle so as to match the position of the upper sheet group that has floated and separated by air blowing,
The sheet bundle may be moved in such a direction (arrow E direction) as to gradually rise obliquely rearward with respect to the stacking surface direction of the sheet bundle (see FIG. 11). By moving the air nozzle 2 in this manner, even a sheet feeding device employing the friction type sheet feeding device 8 can reliably perform sheet separation and prevent double feeding.

Although such a sheet feeding apparatus is not particularly limited in its application range, it can be used as a paper feeding apparatus in a copying machine or an automatic original feeding apparatus, or used as a paper feeding apparatus in a printer or a facsimile. can do. In addition, it may be used as a paper feeding device in a printing press.

In each of the above-described embodiments, the case where the air nozzles 2 are disposed on both side surfaces of the sheet bundle P has been described. However, in the present invention, the air nozzle 2 is disposed on one of the sheet bundles P. Of course, it is also possible to dispose it only on the side surface of.

[0055]

As described above, the sheet feeding apparatus of the present invention moves the position of the air nozzle so as to at least match the position of the uppermost sheet of the stacked sheet bundle. Air is always blown to a certain area of the sheet, and as a result, the uppermost sheet of the sheet bundle can be accurately separated and double feed can be reliably prevented.

Also, even if the size of the sheet to be fed is different, the air nozzle moves so that the distance from the end of the sheet bundle is kept constant, so that the air blowing strength and the like can be reduced. Air can be blown to the end of the sheet bundle under the same conditions without adjustment, so that the uppermost sheet of the sheet bundle can be reliably and stably performed.

After moving the position of the air nozzle so as to match the position of the uppermost sheet, the air nozzle is moved along the laminating surface direction of the sheet bundle or obliquely upward with respect to the laminating surface direction. Because the air is blown more efficiently between the uppermost sheet and the sheet below the uppermost sheet and the sheets are separated in a short time, double feeding is more reliably prevented, It is possible to sufficiently cope with an increase in the speed of the apparatus.

Further, since the nozzle diameter can be changed and the air blowing intensity is adjusted by changing the nozzle diameter, the air flow rate can be adjusted without using a compressor having a large capacity. The air blowing intensity can be finely adjusted (even though it is constant), and by adjusting the air blowing intensity, even sheets with different sheet adhesion due to differences in sheet surface material, basis weight, etc. In addition, it is possible to sufficiently cope with an increase in the speed of the apparatus by slightly increasing the blowing strength and increasing the sheet separation speed, and furthermore, adjusting the floating state of the separated and floating sheet. Can also.

Further, since the air blowing direction of the air nozzle can be changed, air can be blown over the entire surface of the sheet in a short time, and the sheet can be separated more reliably and in a short time. Even if the device speeds up, it can cope with it. In addition, the floating state of the sheet that separates and floats can be adjusted.

According to the present invention, even if the sheets to be used are diversified, it is possible to blow air suitable for each sheet, and as a result, it is possible to reliably separate the sheets, No good sheet feeding can be performed.
In particular, it is possible to perform good sheet feeding without double feeding even for sheets having high smoothness.

[Brief description of the drawings]

FIG. 1 shows a sheet feeding apparatus according to an embodiment of the present invention, in which FIG.
(B) is a principal part front view which shows the installation state of an air nozzle.

FIG. 2 is a conceptual perspective view showing an example of a position detecting unit.

FIG. 3 is an explanatory plan view showing a positional relationship between an air nozzle and an end of a sheet bundle.

FIG. 4 is an explanatory diagram showing a state of sheet separation according to the present invention.

FIG. 5 is a conceptual perspective view showing another example of the position detecting means.

FIG. 6 is a conceptual perspective view showing another example of the position detecting means.

FIG. 7 is a partial cross-sectional explanatory view showing an example of a mounting form of an air nozzle.

FIG. 8 is a conceptual diagram illustrating a sheet feeding apparatus according to another embodiment of the present invention.

FIG. 9 is an explanatory view showing a moving state of an air nozzle in the apparatus of FIG. 9;

FIG. 10 is a conceptual diagram illustrating a sheet feeding apparatus according to another embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a moving state of an air nozzle in the apparatus of FIG.

12A and 12B show configuration examples of a nozzle opening of an air nozzle. FIG. 12A is a state diagram when a nozzle diameter is increased.
(B) is a state diagram when the nozzle diameter is reduced.

13A and 13B show another configuration example of the nozzle opening of the air nozzle. FIG. 13A is a state diagram when the nozzle diameter is increased.
(B) is a state diagram when the nozzle diameter is reduced.

14 is an explanatory diagram showing various modes of changing the position of a nozzle port in the configuration example of FIG.

FIG. 15 is an explanatory plan view showing a configuration example in which the blowing direction of an air nozzle is changed.

FIG. 16 is an explanatory front view showing another configuration example in which the blowing direction of the air nozzle is changed.

FIG. 17 is an explanatory diagram showing another configuration example for changing the blowing direction of the air nozzle.

FIG. 18 is an explanatory diagram showing another configuration example in which the blowing direction (position) of the air nozzle is changed.

FIG. 19 is an explanatory diagram showing a relationship between a blowing direction of an air nozzle and a state of blowing air into a sheet.

FIG. 20 is an explanatory diagram showing a relationship between a blowing direction of an air nozzle and a floating state of a sheet.

FIGS. 21A and 21B show a configuration example of a tray (bottom plate) on which a sheet bundle is placed, and FIG. 21A is a schematic perspective view of the tray;
(B) is a sectional view taken along line BB of (a).

FIG. 22 is a conceptual diagram illustrating a sheet feeding apparatus according to another embodiment of the present invention.

[Explanation of symbols]

2 ... air nozzle, 3 ... position detection means, 4 ... nozzle position control means, P ... sheet bundle, P ₁ ... top sheet, r ...
Nozzle diameter.

Claims (5)

[Claims] 1. An apparatus for feeding sheets one by one while blowing air from an air nozzle onto a bundle of stacked sheets to promote separation of the sheets, wherein the air is blown from the air nozzle. Position detecting means for detecting the position of the uppermost sheet of the sheet bundle; and at least the position of the air nozzle movably installed at the position of the uppermost sheet in accordance with the detection information of the position detecting means. A sheet feeding device comprising a nozzle position control means for moving the sheet feeding so as to be aligned. 2. The sheet feeding device according to claim 1, wherein the air nozzle is movable so that a distance between the air nozzle and an end of the sheet bundle is kept constant even when the size of the sheet bundle is different. apparatus. 3. The nozzle position control means moves the position of the air nozzle so as to match the position of the uppermost sheet, and then moves along the stacking surface direction of the sheet bundle or with respect to the stacking surface direction. 2. The sheet feeding device according to claim 1, wherein the sheet feeding device is set so as to be moved obliquely upward. 4. The sheet feeding device according to claim 1, wherein the air nozzle has a structure in which the nozzle diameter can be changed, and the air nozzle is changed to adjust the air blowing intensity. 5. The sheet feeding device according to claim 1, wherein the air nozzle has a structure in which an air blowing direction of the nozzle can be changed.