JP2809282B2 - 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.

Therefore, the applicant increases the feeding force by suctioning the upper surface of the sheet paper to the feed-side conveying means by negative pressure, and increases the friction force on the forward-stopping side by sucking the back surface of the sheet paper toward the forward-stopping means, It has been proposed to enlarge the difference between the forward stopping force and the frictional force between the sheets (see JP-A-3-120132). In this case, it is desirable that the feed-side negative pressure suction means for applying a negative pressure to the feed side can be efficiently sucked by a pump or a fan as small as possible, and it is desirable that the paper can be fed at a constant feeding interval.

(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 easy compared with the conventional negative pressure suction method.The sheet paper is fed efficiently with a small air pump or fan. It is an object of the present invention to provide a sheet feeding device capable of sucking a sheet to a conveying means and stably separating and feeding a sheet of paper having different qualities and thicknesses at a constant interval.

(Constitution of the Invention) According to the present invention, the object is to provide a feed-side transport unit that contacts a surface of a sheet paper and transports the sheet paper in a feed direction by a frictional force determined by a product of the contact pressure and a friction coefficient; Forward blocking means for contacting the back surface of the sheet paper to prevent the advancement of the sheet paper by a frictional force determined by a product of the contact pressure and the friction coefficient, wherein the frictional force on the feed side and the frictional force on the forward blocking side In a friction-separation type sheet feeding device that sets a sheet to be separated and feeds one by one by setting the frictional force between sheet sheets to be larger than each other, the feed-side conveying unit includes a plurality of sheets divided in a direction orthogonal to a feeding direction. A feed belt, a sheet position detecting means for detecting the sheet paper at the exit side of the feed side conveying means, and the sheet paper only while the sheet position detecting means does not detect the sheet paper. A feed-side negative pressure suction means for increasing the feed-side frictional force by sucking the feed belt side at a position corresponding to the paper sheet storage portion and the advance prevention means. A plurality of reverse rollers provided with elastic return behavior so as to enter the feed belt from below to a position overlapping with the feed belt; and And a forward blocking side negative pressure suction means for increasing the pressure.

Here, the suction points are connected to a common duct, which can keep the feed interval constant by introducing air into the duct by means of an air valve opened by the leading edge of the sheet.

In addition, the suction points may be pulled to a negative pressure by independent ducts, and each duct may be provided with an electromagnetic valve or a mechanical rotary valve, and these may be opened and closed in synchronization with paper feeding.

(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 _f0 for the first 11C~E diagram sheet thickness t, the reverse force F _r0, a graph showing changes in the frictional force F _p0 between paper, as in the conventional apparatus, respectively, negative pressure P _s only the feed side 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 sent from right to left in FIG. 11A by feed belt 1, and lower sheet paper 6 is returned by reverse roller 4 in the reverse direction. At this time, the force by which the feed belt 1 feeds the paper 5 to the left, that is, the feed force F _f0 , becomes F _f0 = μ _f0 · P _f0 , where the friction coefficient is μ _f0 and the contact pressure is P _f0 . The reverse roller 4 is force or reverse force F _r0 return paper 6, the friction coefficient mu _r0, the contact pressure as P _r0, the _{F r0 = μ r0 · P r0} . Further, the frictional force F _p0 between the papers 5 and 6 is F _p0 = μ _p0 · P _{p0 where} the friction coefficient is μ _p0 and the contact pressure is P _p0 . In the conventional friction separation method using no negative air pressure, the negative pressure P _s0 = 0, and at this time, P _f0 = P _r0 = P _p0 = P.

To ensure that the paper 5 is separated from 6 in this state, F _f0 > F _r0 > F _p0 μ _f0 > μ _r0 > μ _p0 must always hold and be as shown by the solid line in FIG. 11C. . However, in practice, these friction coefficients μ _f0 ,
μ _r0 and μ _p0 change under the influence of paper quality, thickness, humidity, dirt on the surface of the belt 1 or the roller 4 or conditions such as friction, and this relationship may not be established. Means that paper cannot be separated. In FIG. 11C, dotted lines F _f0 ′, F _r0 ′, and F _p0 ′ indicate that the 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 _f0 ′ and the reverse force
In order to increase F _r0 ′, the contact pressure P may be increased,
At this time, the contact pressure P _p0 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 is, F f = μ f · (} P f + P s) ( Example) Figure 1 shows a schematic of an embodiment of the present invention Side view, second
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 passed through reflectors 22, 24 and a lens 26,
It 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. 3 is a detailed view of a portion corresponding to FIG. 1, FIG. 4 is a cross-sectional view taken along line IV-IV, FIGS. 5 and 6 are longitudinal 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 forming a part of the feed-side conveying means, 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 serving as a storage unit 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 located below the feed roller 42. It is pressed by the 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, thereby promoting 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 a forward blocking unit that is elastically pressed against 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 held at one end of a swing arm 60 that swings about a fulcrum 58, while the other end of the arm 60 is pulled downward by a tension coil spring 62. Stopper
At 64, the clockwise rotation is regulated. As a result, the feed belt 40 is
The elastic return behavior is given so as to enter from below.

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. The reverse roller 56 descends for a thick document or a hard document 18 to allow the document to pass smoothly. Here, the reverse roller 56 is located not diagonally below the feed roller 44 but diagonally below the roller 42, and as shown in FIG.
, And the effect of preventing double feed of thin paper is particularly enhanced.

Note the feed force F _f of the feed belt 40 determines the the material and the number to be greater than the forward regulations ring 72 (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 is provided with openings 92 and 94 serving as suction points at portions requiring a large negative pressure.
That is, the opening 92 corresponds to a hopper portion where the document 18 is sucked from the cassette 46, and the opening 94 corresponds to a separation portion where the plurality of overlapping documents 18 are separated between the feed belt 40 and the reverse roller 56. 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 serving as a sheet position detecting unit that is pushed up by the document 18 behind the feed roller 44, and a link 100 that connects a rotating end of the lever 98 and the valve 96. When the document 18 is separated and fed between the feed belt 40 and the reverse roller 56, the leading edge of the document 18 pushes the lever 98 to the imaginary line position in FIG. The rotation causes the air valve 96 to be pushed upward by the link 100. Therefore, the air valve 96
Is opened, outside air is introduced into the duct 82, and the negative pressure in the duct 82 decreases (approaches atmospheric pressure). Therefore, the next original 18 is not sucked by the opening 92 and is not sent. In this manner, until one document 18 passes through the lever 98 and the air valve 96 closes, the feeding operation of the next document 18 is restricted, and the feeding interval of the document 18 is kept constant.

Reference numeral 102 denotes a negative pressure suction means on the forward blocking side, that is, on the reverse side. This means 102 comprises a duct 104, a centrifugal fan 106
And The duct 104 covers the reverse roller 56 from below, and the negative pressure generated by the fan 106 is always guided near the upper edge of the reverse roller 56. 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 in which the document 18 is placed is cassette, the bottom plate 48 pushes up the document 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, and preparation for starting operation is completed. When the user presses a start switch (not shown), the motors 66, 88, 108, etc. operate. While the feed belt 44 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 44 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 F _f on the upper surface of the document 18, the forward blocking force F _r to the lower surface (reverse power) is acting I do.

Here, F _f = μ _f · (P _f + P _s1 ) _Fr = 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 _Fr , and the frictional 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, and the negative pressure of the duct 82 decreases, so that the next document 18 is not sucked by the cassette 46 and the conveyance thereof is stopped.
At this time, since the negative pressure on the forward blocking side is always acting on the document 18, the separation is surely performed. Original 18 is lever
After passing through 98, the air valve 96 is closed, the next original 18 is attracted from the cassette 46 to the feed belt 44, and the paper feeding is resumed.

This embodiment includes a device 112 for correcting the skew of the fed document 18. As shown in FIGS. 3 and 8, this device 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 tilted, 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. The feed-side negative pressure suction means 80A of this embodiment is provided by ducts 150 and 152 for guiding negative pressure to necessary portions of the feed belt 40, and the reverse-side negative pressure suction means 102A is provided by a duct 154 for guiding negative pressure to the reverse roller 56. Each of them is formed, and these are formed into one centrifugal fan 156.
And the respective ducts 150, 152, 154 are switched by electromagnetic air valves (hereinafter referred to as electromagnetic valves) 158, 160, 162. Here, each solenoid valve 158, 160, 16
The opening / closing timing of 2 is detected by appropriate sensors 164, 166 and the like for detecting the feed position of the document 18. In this case the sensor
Reference numerals 164 and 166 are provided on the entrance side and the exit side of the feed belt 40, respectively, and detect the entry and exit of the document 18.

In the embodiment of FIG. 9, the feed roller 42 near the cassette 46A is driven by the motor 66A. In this way, even when the belt 40 comes into direct contact with the bottom of the cassette 46 and a large driving force is applied to the belt 40 when feeding the last one original 18 remaining in the cassette 46A, the belt 40 is Relax on the side. Therefore, the pressing force between the belt 40 and the reverse roller 56 does not become excessive, 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.

(Effect of the Invention) As described above, the invention described in claim 1 is provided with a reverse roller provided with elastic return behavior between a plurality of feed belts so as to enter from a side view, The feed-side transport means is provided with feed-side negative pressure suction means for sucking the sheet paper to increase the frictional force on the feed side, and the forward-stopping means is for suctioning the sheet paper to increase the frictional force on the forward-stopping side. Since the blocking side negative pressure suction means is provided, the feeding force for conveying the sheet paper in the feeding direction, the frictional force (reverse force) on the forward blocking side for preventing the sheet paper from advancing, the frictional force between the papers, Is increased, and the separation of the sheet paper can be performed stably and reliably.

In particular, one of the negative pressure suction positions of the feed side negative pressure suction means is opposed to the advance prevention means, so that even if the heads of a plurality of sheet papers are transported in a state shifted in the transport direction,
The negative pressure effectively acts on both sides of the sheet paper, and the sheet is reliably separated by the advance prevention means.

Further, the suction portion is located at a position facing the sheet paper storage portion and the advance prevention means, and only increases the difference between the frictional force between the feed side and the reverse side and the frictional force between the heavy sheet papers. The size of the air pump or the fan can be reduced. Here, since a negative pressure is guided to the suction side on the feed side in synchronization with the paper feed position, the paper feed interval can be kept constant. At this time, since the negative pressure on the reverse side always acts on the sheet paper, double feeding of the sheet paper can be reliably prevented. For example, an air valve is opened at the leading edge of the paper to guide the atmosphere to a duct connected to the suction side on the feed side (the invention of claim (2)), or a duct for guiding the intake air to the suction side on the feed side is provided independently. These ducts may be provided with an electromagnetic air valve or a mechanical rotary air valve that opens and closes in synchronization with the front end position of the sheet paper (the invention of claim (3)).

[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 view showing a second embodiment, and FIG.
10A to 10E are explanatory diagrams of the principle of the present invention. A: paper feeder, 18: original as sheet paper, 40: feed belt as feed-side transport means, 54: cassette as sheet paper storage unit, 56 ... reverse roller as forward-stopping means , 80, 80A ... Negative pressure suction means on the feed side, 82 ... Duct, 92, 94 ... Opening as suction point, 96 ... Air valve, 98 ... Lever as sheet position detection means, 102 ... Forward Blocking side negative pressure suction means, 150, 152, 154 ... duct, 158, 160, 162 ... electromagnetic air valve, 164, 166 ... sensor as sheet position detection means, 170 ... rotary air valve.

Claims (3)

(57) [Claims] A feed-side conveying means for contacting the front surface of the sheet paper to convey the sheet paper in a feed direction by a frictional force determined by a product of the contact pressure and the friction coefficient; Advancement inhibiting means for inhibiting advancement of the sheet paper by a frictional force determined by a product of the contact pressure and the friction coefficient, wherein the frictional force on the feed side is made smaller than the frictional force on the advancement inhibiting side and the frictional force between the sheets. In a friction-separation type sheet feeding device that sets a large sheet and separates and feeds the sheet paper one by one, the feed-side conveying means includes a plurality of feed belts divided in a direction orthogonal to a feeding direction, and the sheet paper. Sheet position detecting means for detecting at the exit side of the feed side conveying means, and the sheet paper is stored in the sheet paper storage portion and the advance prevention while the sheet position detecting means does not detect the sheet paper. Feed-side negative pressure suction means for increasing the feed-side frictional force by suctioning to the feed belt side at a position corresponding to the step, wherein the advance prevention means is configured to overlap the feed belt to a position overlapping the feed belt in a side view. A plurality of reverse rollers having elastic return behavior so as to enter from below, and a forward blocking negative pressure suction means for constantly sucking the sheet paper toward the reverse roller to increase a forward blocking friction force. And a sheet feeding device. 2. The suction point of the feed-side negative pressure suction means is connected to a common duct, the duct has an air valve for guiding the atmosphere into the duct, and the sheet position detection means has passed through the feed-side conveyance means. 2. The sheet feeding device according to claim 1, further comprising a lever pushed by the front edge of the sheet paper to swing and open the air valve. 3. The feed-side negative pressure suction means includes a plurality of ducts for connecting a negative pressure suction fan and a suction point, and an electromagnetic air valve interposed between the ducts. 2. A sheet feeding apparatus according to claim 1, further comprising a sensor for detecting a sheet at an outlet side of said means.