JP2851650B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention includes feed-side and advance-stopping-side conveying means pressed against the front and back surfaces of sheet paper, respectively. The present invention relates to a friction separation type sheet feeding device that separates and feeds sheet sheets one by one using a difference in frictional force between the sheet feeding devices.

(Technical Background of the Invention) Many OA (office automation) devices use sheet paper cut to a fixed size, and it is necessary to feed the sheet paper one by one reliably and at high speed. As such a sheet paper feeding method, a method using a frictional force (friction method) and a method using a suction force by negative air pressure (negative pressure suction method) are conventionally known.

In the apparatus utilizing frictional force, a conveying means such as a roller or a belt is pressed against the surface of the sheet paper, and the paper is drawn out by the frictional force between the two. However, in this method, since the frictional force between the stacked papers is the same, a plurality of sheets are pulled and sent together with the paper on the surface, so that there is a problem that a so-called double feed easily occurs.

In order to prevent this double feeding, there has been proposed a device provided with a friction pad which contacts the back surface of the paper to prevent the paper from advancing, or a device provided with a friction roller which is pressed against the back surface of the paper and rotates in a direction to return the paper. (Friction separation method). However, in this method, the difference between the frictional force between the contacting parts on the front and back sides of the paper and the frictional force between each paper is used, so separation is caused by changes in paper quality, thickness, etc., or changes in the friction coefficient due to use. There is a problem that the operation is likely to be unstable.

On the other hand, in the method using the suction force by the negative air pressure, the paper is sucked up by the negative air pressure and transported, so that a large air pump that generates a large suction force is required. In addition, since it is necessary to adjust the suction negative pressure depending on the quality and thickness of the paper and to change the suction position according to the dimensions of the paper, the adjustment is troublesome.

(Object of the Invention) The present invention has been made in view of such circumstances,
The operation is more stable than the conventional friction separation method, and a large air pump is not required and the adjustment is simple compared to the conventional negative pressure suction method. It is an object of the present invention to provide a friction-separation-type paper feeder capable of separating paper into paper.

(Constitution of the Invention) According to the present invention, the object is to contact the surface of the sheet paper at a plurality of positions separated in the width direction of the sheet paper and to apply the frictional force determined by the product of the contact pressure and the friction coefficient to the sheet paper. A plurality of feed-side conveying means for conveying in the feed direction;
Advancing prevention means for contacting the back surface of the sheet paper between the feed-side transporting means and inhibiting advancement of the sheet paper by a frictional force determined by a product of the contact pressure and a friction coefficient;
By setting the frictional force on the feed side to be larger than the frictional force on the forward blocking side and the frictional force between the sheet papers,
In a friction separation type paper feeder that separates and feeds sheets one by one,
A feed-side negative means for continuously sucking the surface of the sheet paper to the feed-side transport means side from the negative-pressure suction opening facing the advance prevention means from between the feed-side transport means to increase the frictional force. A pressure suction means; and a forward blocking negative pressure suction means for continuously sucking the back surface of the sheet paper toward the forward blocking means around the forward blocking means to increase the frictional force. Paper feeder.

The same object can also be achieved by omitting the suction means on the feed side and providing the suction means only on the advance prevention side.

(Principle) Next, the principle of the present invention will be described with reference to FIGS. 11A to 11E.
The 11A figure schematic diagram, the 11B diagram shows the change of the feed force F _f to the size P _s of the negative pressure acting on the feed side,
Feed force F _fo for the first 11C~E diagram sheet thickness t, the reverse force F _ro, a graph showing changes in the frictional force F _po between paper, as in the conventional apparatus, respectively, only the feed side negative pressure P _s It is shown and when added, negative pressure P _s in the feed side and the reverse side, and when the addition of P _r.

In FIG. 11A, reference numeral 1 denotes a feed belt, which is wound around a pair of feed rollers 2 and 3. Reference numeral 4 denotes a reverse roller which rotates in the opposite direction to the feed rollers 2 and 3, and is pressed against the feed belt 1 from below by a coil spring 4a. Sheet papers 5 and 6 of a predetermined size are fed by feed belt 1 from right to left in FIG. 11A,
The lower sheet paper 6 is returned by the reverse roller 4 in the reverse direction. Force this time feed belt 1 sends paper 5 to the left, i.e. the feed force F _fo is the coefficient of friction mu _fo, the contact pressure as P _fo, the _{F fo = μ fo · P fo} . The force by which the reverse roller 4 returns the paper 6, that is, the reverse force F _ro, is F _ro = μ _ro · P _ro , where the friction coefficient is μ _ro and the contact pressure is P _ro . Further, the frictional force F _po between the papers 5 and 6 is expressed as F _po = μ _po · P _po with a friction coefficient μ _po and a contact pressure P _po . In the conventional friction separation method using no negative air pressure, the negative pressure P _so = 0, and at this time, P _fo = P _ro = P _po = P.

In this state, in order for the paper 5 to be surely separated from 6, the _relation F _fo > F _ro > F _po μ _fo > μ _ro > μ _po must always hold, as shown by the solid line in FIG. 11C. . However, in practice, these friction coefficients μ _fo ,
μ _ro and μ _po change under the influence of conditions such as paper quality, thickness, humidity, dirt on the surface of the belt 1 and the roller 4 or abrasion state, and this relationship may not be established. Means that paper cannot be separated. In FIG. 11C, the dotted lines F _fo ′, F _ro ′, and F _po ′ show the state in which the respective results are close to each other. From this figure, it can be seen that these forces approach and the separation becomes unstable particularly in the case of thin paper. Under such circumstances, the feed force F _fo ′ and the reverse force
To increase F _ro ′, the contact pressure P may be increased,
At this time, the contact pressure P _po between the papers 5 and 6 also increases, and it is difficult to improve the separability.

The present invention solves this problem by acting negative pressure P _s which adsorbs paper 5 to the feed belt 1.
FIG. 11D illustrates this state. That feed force F _f acting on the paper 5 above by the negative pressure P _s, while increasing the _{F f = μ f · (P} f + P s), the negative pressure P _s is almost the paper 6 below Since it does not work, F _ro and F _po do not change. This increase in feed force F _f is significant enough thin paper as shown in 11B diagram (t = small). The result feed force F _f is increased greatly thin side as the 11D FIG. Therefore, the interval between F _f , F _ro , and F _po widens,
In particular, the separation stability of thin paper can be significantly improved.

The negative pressure can be applied not only to the feed belt 1 but also to the reverse side. In this case, the reverse force F _ro increases as the 11E Figure F _r, and since the contact pressure P _p between the paper 5 and 6 is reduced frictional force F _po reduced to F _p.
As a result, the intervals between F _f , F _r , and F _p are further increased, and the separation of the paper is further stabilized and ensured.

Further, when a sufficiently large feed force by as high the material coefficient of friction or increase the number of feed belts, desired object be added a negative pressure P _r only the reverse side is achieved it can.

(Embodiment) FIG. 1 is a side view schematically showing an embodiment of the present invention, and FIG.
The figure is a side view of a microfilm rotary camera to which this is applied.

This rotary camera prints an original supplied from the paper feeding device A according to the present invention on a microfilm. Since this rotary camera is basically the same as that shown in Japanese Patent Application No. 63-184480, only its outline will be described here.

In FIG. 2, reference numeral 10 denotes a rotary drum having a number of small holes formed on the surface thereof. Inside the drum 10, a negative pressure chamber 12 and a positive pressure chamber 14 are defined by partition walls. The negative pressure chamber 12 is suctioned to a negative pressure by a suction fan (not shown),
The positive pressure chamber 14 is guided by the discharge pressure of a blowing fan (not shown). For this reason, the original 18 supplied from the sheet feeding device A to the surface of the drum 10 facing the negative pressure chamber 12
Is attracted to the surface of the drum 10 by the negative pressure, and rotates counterclockwise with the drum 10 in FIG. The original 18 conveyed by the drum 10 is illuminated by a light source 20, and the image of the original 18 is transmitted through a reflection plate 22, 24 and a lens 26 to a film magazine 28.
Is led to. The image is transferred to a microfilm 30 fed in synchronization with the drum 10 in the film magazine 28. Also, the photographed original 18 is in the positive pressure chamber.
The paper is separated from the drum 10 by the air blasting from the surface of the drum 10 to the surface of the drum 10 and collected on a discharge tray 32 for receiving the original. In addition, air is sent from the paper discharge fan 16 to the paper discharge table 32, and the discharge of the document is promoted.

Next, the sheet feeding device A will be described with reference to FIG. 1 and FIGS. FIG. 3 is a detailed view of a portion corresponding to FIG. 1, FIG. 4 is a cross-sectional view taken along the line IV-IV, FIGS. 5 and 6 are vertical cross-sectional views of the vicinity of the intermediate roller and the ejection roller, and FIG. FIG. 8 is a cross-sectional view taken along the line VII-VII in FIG.

In these figures, reference numeral 40 denotes a feed belt, which is wound around feed rollers 42 and 44. Here, a plurality of, for example, three feed belts 40 are arranged in parallel at appropriate intervals. Reference numeral 46 denotes a cassette for storing the original 18, and a bottom plate 48 of the cassette 46 is elastically pressed upward about a fulcrum 50, and the surface of the uppermost original 18 is fed by a feed roller 42.
It is pressed by the lower feed belt 40. As a result,
The original 18 is carried in the feed direction by the travel of the feed belt 40. That is, the feed belt 40 is a feed-side transport unit that transports the document 18 to the feed side.

Here, the front wall 52 of the cassette 46 is inclined so that the upper part thereof is deviated in the document feeding direction to promote separation of the document 18. An intermediate roller 54 faces the space between the feed belts 40 facing the upper edge of the front wall 52 (FIG. 5). This intermediate roller 54 is fixed to a duct 82 to be described later, and the vertical movement thereof is regulated.By maintaining a constant gap between the intermediate roller 54 and the upper edge of the front wall 52, a multi-feed in which a large number of originals 18 are sent at one time while overlapping is performed. Preliminarily prevent.

Reference numeral 56 denotes a reverse roller, which serves as forward blocking means for pressing the back surface of the document 18 carried by the feed belt 40 to prevent the document 18 from moving forward. As shown in FIG. 3, the reverse roller 56 is a swing arm that swings about a fulcrum 58.
While held at one end of the arm 60, the other end of the arm 60 is pulled downward by a tension coil spring 62, and its rotation in the clockwise direction is restricted by a stopper 64.

The feed roller 44 and the reverse roller 56 are motors.
The belt is driven clockwise in FIG. 3 by 66, and the reverse roller 56 rotates at about twice the speed of the feed roller 44 to allow for rapid paper separation. The reverse roller 56
Is moved up and down, a spring joint 70 connects between a pulley 68 (FIG. 4) driven by a motor 66 and a shaft of the reverse roller 56. In addition, the reverse roller 56 is disposed between the three feed belts 40.
It has a ring 72 of books. The upper edge of the ring 72 is located above the lower surface of the feed belt 40 in the state of FIG. 3 in which the swing arm 60 has hit the stopper 64 (FIG. 4). As shown in FIG. 4, the wire is bent like a wave passing between the lower surface of the belt 40 and the upper edge of the ring 72. Here, the reverse roller 56 descends for a thick document or a hard document 18 to allow the document to pass smoothly. Here, since the reverse roller 56 is located not diagonally below the feed roller 44 but diagonally below the roller 42, it is possible to make the reverse roller 56 deeply enter between the feed belts 40 as shown in FIG. The effect of preventing double feeding of thin paper is particularly enhanced.

Incidentally feed forward control force feed force F _f is by ring 72 of the belt 40 to decide the material and the number to be greater than the (reverse force F _r) is desirable. For example, a silicon rubber belt is used for the feed belt 40, and a neoprene rubber belt is used for the ring 72.

In particular, in the case of a thin original 18, the original may easily bend in a wavy shape, so that the original 18 may slip between the feed belt 40 and the ring 72 while overlapping. In order to prevent this, a separate ring 74 is provided between the feed belts 40 on the feed roller 44 as shown in FIG.

Reference numeral 76 denotes an ejection roller, which is pressed against the feed roller 44 from below by a leaf spring 78 (FIG. 6). The pushing roller 76 presses the original 18 between the feed roller 44 and the feed roller 44 by pressing the original 18 against the feed belt 40.
The end of the document 18 compensates for a decrease in the feeding force when the document 18 is separated from the feed belt 40, and the document is smoothly sent to the end.

Next, the feed side negative pressure suction means 80 will be described. 82 is a sheet metal duct, the lower part of which covers the feed belt 40 and the feed rollers 42, 44, and the upper part thereof is a centrifugal fan 84.
Is the case. The centrifugal fan 84 is rotated by, for example, a motor 88 (FIG. 1) via a belt 86,
A negative pressure of about 5 to 10 cmHg is generated inside. A lower portion of the duct 82 is provided with a wind shield 90 that passes between the feed belts 40 in the front-rear direction and closes the lower opening of the duct 82.
As shown in FIGS. 3 and 4, the 90 has openings 92 and 94 at portions requiring a large negative pressure. That is, the opening 92
Corresponds to a hopper portion for adsorbing the original 18 from the cassette 46, and the opening 94 has a plurality of overlapping originals 18 in the feed belt 40.
And the reverse roller 56 is separated. In this way, the capacity of the centrifugal fan 84 can be further reduced by concentrating the negative pressure from the openings 92 and 94 to act on the hopper section and the separation section.

The duct 82 is provided with an air valve 96. The air valve 96 includes a lever 98 that is pushed up by the leading edge of the document 18 behind the feed roller 44,
A link 100 for connecting the rotation end of the valve 98 and the valve 96 is provided. Then, the original 18 is fed by the feed belt 40 and the reverse roller.
When the document 18 is separated and fed, the leading edge of the document 18 pushes the lever 98 to the position indicated by the imaginary line in FIG. 3 and pivots. Push up. Therefore, the air valve 96 is opened, and outside air is introduced into the duct 82, and the negative pressure in the duct 82 decreases (approaches the atmospheric pressure). Therefore, the missing original 18 is not attracted to the opening 92 and is not sent. In this way, one original 18 is
Until the air valve 96 is closed after passing through the 98, the feeding operation of the next original 18 is restricted, and the feeding interval of the original 18 is kept constant.

Numeral 102 is a negative pressure suction means on the forward blocking side, that is, on the reverse side. The means 102 includes a duct 104 and a centrifugal fan 106. The duct 104 covers the reverse roller 56 from below, and the negative pressure generated by the fan 106
It is led near the upper edge of. The fan 106 is driven by a belt, for example, by a motor 108 (FIG. 1).

Next, the operation of this embodiment will be described. When the cassette 46 containing the original 18 is set, the bottom plate 48 pushes up the original 18. When the document 18 is set at a predetermined position, the document detection sensor 110 (FIG. 3) including a limit switch is turned on,
Preparation for operation start is completed. When the user presses a start switch (not shown), the motors 66, 88, 108, etc. operate. While the feed belt 40 rotates, the fan 84 of the feed-side negative pressure suction means 80 rotates, and the pressure inside the duct 82 becomes negative. Thus the original 18 is fed to a negative pressure and a feed direction with a sufficiently large feed force F _f (drawing left) acting from the friction force and the opening 92 by the feed belt 40 to the document 18. Preliminary multifeed is prevented by a gap between the front wall 52 of the intermediate roller 54 and the cassette 46, a feed force of the upwardly F _f on the document 18, the forward blocking force downward to F _r (reverse power) is acting I do.

Here, F _f = μ _f · (P _f + P _s1 ) F _r = μ _r · (P _r + P _s2 ) (where P _s1 is the negative pressure on the feed side and P _s2 is the negative pressure on the reverse side). As described in, the difference between the feed force F _f , the reverse force F _r , and the friction force F _p between the originals increases, and the original 18
Is reliably separated. When the document 18 pushes the lever 98 open, the air valve 96 opens, the negative pressure in the duct 82 decreases, and the conveyance of the next document 18 is stopped. When the document 18 passes through the lever 98, the air valve 96 closes and the feeding of the next document 18 is restarted.

This embodiment includes a device 112 for correcting the skew of the fed document 18. As shown in FIGS. 3 and 8, the apparatus 112 includes a pair of left and right rollers 118 and 120 driven by stepping motors 114 and 116, pinch rollers 122 and 124 which are in rolling contact with these rollers 118 and 120, and A pair of left and right optical sensors 12 that are located downstream and detect the leading edge of the document 18
6, 128. And the original carried by the belt 40
If 18 is inclined, its leading edge blocks one of the optical sensors 128 (or 126), and accordingly, only the left (right) roller 118 (120) is rotated, so that both optical sensors 126 and 128 are rotated. Manuscript
Try to detect 18 leading edges. Manuscript 18
Correct the bend and send it to the rotary camera.

FIG. 9 is a view showing a second embodiment. In this embodiment, the feed-side negative pressure suction means 80A is provided by ducts 150 and 152 for guiding negative pressure to required portions of the feed belt 40, and the reverse side negative pressure suction means 102A is provided by duct 154 for guiding negative pressure to the reverse roller 56. And form a single centrifugal fan 156
And each duct 150, 152, 154 is connected to a solenoid valve 158, 160, 162
It is designed to switch with. Here each solenoid valve 15
The opening / closing timing of 8, 160, 162 is detected by an appropriate sensor 164, 166 or the like for detecting the feeding position of the document 18.

FIG. 10 is a view showing a third embodiment. The feed side negative pressure suction means 80B is a machine which switches in synchronization with the running of the feed belt 40 in place of the solenoid valves 158 and 160 in FIG. This uses a rotary valve 170 of the type. That is, the rotation of the feed roller 42 is controlled by the valve 170 at a predetermined speed ratio.
The valve 170 is synchronized with the moving position of the document 18 by the transfer to the predetermined ducts 150 and 152 at the predetermined document 18 position.
To induce negative pressure. In this embodiment, the air discharged from the fan 156 is blown out from the nozzle 172 toward the front edge of the moving document 18 without introducing a negative pressure to the reverse roller 56, and the blowing air facilitates separation of the document 18. I made it.

9 and 10, the feed roller 42 near the cassette 46A is driven by the motor 66A. In this way, when a large driving force is applied to the belt 40 when the last one original 18 in the cassette 46A is fed, the belt
40 is loosened on the reverse roller 56 side. Therefore, the pressing force between the belt 40 and the reverse roller 56 is reduced, and the wear of the reverse roller 56 can be prevented.

In each of the embodiments described above, the present invention is applied to the paper feeder A for feeding the original 18 of the rotary camera. However, the present invention is applicable to a device for feeding various types of sheet paper such as a copy, a facsimile, and a printer. The present invention is applicable to devices for separating bills and cards, and includes these.

Further, in the above embodiment, the reverse roller 56 is used as the advance prevention means for preventing the advance of the document (sheet paper), but the present invention may use a non-rotating friction material such as a friction pad. .

Further, the negative pressure suction means may be provided not only on both the feed side and the forward prevention (reverse) side but also only on the reverse side.

(Effects of the Invention) As described above, the invention described in claim 1 applies the negative pressure suction opening facing the advance prevention means from between the plurality of feed-side conveyance means to the surface of the sheet paper. A feed-side negative pressure suction means is provided for continuously suctioning the feed-side conveying means and increasing the frictional force on the feed side. Since a forward blocking negative pressure suction means for sucking the paper and increasing the frictional force is provided, the feeding force for conveying the sheet paper in the feed direction and the forward blocking frictional force for preventing the sheet paper from moving forward are provided. The difference between the (reverse force) and the frictional force between the papers increases, and the separation of the sheet paper can be performed stably and reliably. Further, the negative pressure used for the negative pressure suction means is smaller than that of the conventional negative pressure suction system in which paper is sucked up and transported by the negative pressure, so that a large air pump is not required, and, for example, a fan of about the size of a blowing fan can be used sufficiently. Since it becomes possible, adjustment of the device is also simplified.

Further, according to the invention described in the second aspect, the forward blocking side negative pressure suction means for continuously sucking the back surface of the sheet paper around the forward blocking means toward the forward blocking means to increase the frictional force is provided. Because of the provision, the separation of the sheet paper can be improved, and a great effect can be obtained particularly when the feed force is sufficiently increased by using a material having a large friction coefficient on the feed side.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing an embodiment of the present invention, FIG. 2 is a side view of a microfilm rotary camera to which the embodiment is applied, FIG. 3 is a detailed view of a portion corresponding to FIG. 1, and FIG. Is a sectional view taken along the line IV-IV, FIGS. 5 and 6 are longitudinal sectional views showing the vicinity of the intermediate roller and the ejection roller, FIG. 7 is a sectional view taken along the line VII-VII in FIG. 3, and FIG. It is a top view of a correction part. FIG. 9 is a diagram showing the second embodiment, FIG. 10 is a diagram showing the third embodiment, and FIGS. 11A to 11E are diagrams explaining the principle of the present invention. A: paper feeder, 18: document as sheet paper, 40: feed belt as feed-side conveying means, 56: reverse roller as forward-stopping means, 80, 80A, 80B: feed-side negative pressure suction means, 102, 102A: Forward suction side negative pressure suction means.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-37636 (JP, A) JP-A-50-138900 (JP, A) JP-A-54-61772 (JP, A) JP-A 52-138 75769 (JP, A) JP-A-53-71464 (JP, A) JP-B-53-31703 (JP, Y2) JP-B-48-19673 (JP, B1) JP-B-51-45095 (JP, Y1) (58) Field surveyed (Int.Cl. ⁶ , DB name) B65H 3/12 B65H 3/52 B65H 3/64

Claims (2)

(57) [Claims] A plurality of feed sides contacting the surface of the sheet at a plurality of positions separated in a width direction of the sheet and conveying the sheet in a feed direction by a frictional force determined by a product of the contact pressure and a friction coefficient. A conveying unit; and a feed-preventing unit that contacts a back surface of the sheet paper between the feed-side conveying unit and that prevents the sheet paper from moving forward by a frictional force determined by a product of the contact pressure and a friction coefficient. Separation-type sheet feeding device for separating and feeding sheets one by one by setting the frictional force on the sheet side to be larger than the frictional force on the forward blocking side and the frictional force between sheet sheets, Feed-side negative pressure suction means for continuously suctioning the surface of the sheet paper to the feed-side transport means side from the negative pressure suction opening opposed to the advance prevention means from above to increase the frictional force. Feeding means for continuously suctioning the back surface of the sheet paper to the side of the advance prevention means around the advance prevention means and increasing the frictional force thereof. apparatus. 2. A plurality of feed sides which contact the surface of the sheet paper at a plurality of positions separated in the width direction of the sheet paper and convey the sheet paper in a feed direction by a frictional force determined by a product of the contact pressure and a friction coefficient. A conveying unit; and a feed-preventing unit that contacts a back surface of the sheet paper between the feed-side conveying unit and that prevents the sheet paper from moving forward by a frictional force determined by a product of the contact pressure and a friction coefficient. The frictional separation type sheet feeding device which separates and feeds the sheet paper one by one by setting the frictional force on the sheet side to be larger than the frictional force on the forward blocking side and the frictional force between the sheet papers. A sheet feeding device, comprising: a forward blocking side negative pressure suction unit that continuously suctions the back surface of the sheet paper to the forward blocking unit side to increase the frictional force.