JPH05270682A - Overlap-feed preventive device for feeding sheet - Google Patents

Abstract

PURPOSE:To prevent the overlap-feed of sheets and ease maintenance, by containing a coil spring between a driven roller and a roller shaft, and connecting the roller and the roller shaft via the coil spring so as to permit roller turning with the coil spring elastically opened in a loose direction only at the time of turning in a sheet-feeding direction. CONSTITUTION:When one sheet is fed between a driving roller 28 and a driven roller 29, the sheet is made free turning in a space with a roller shaft 27 side, because a spring 58 in the driven roller 29 is twisted in the loose direction of a coil diameter. In contrast with this when end parts of two or more sheets 67a and 67b are fed between both the rollers 28 and 29, slipping is caused between the sheets 67a and 67b, and only the sheet 67a, contacting with the driving roller 28 side, is fed and the other sheets are stopped. At that time, the spring 58 in the driven roller 29 is elastically restored in a fastening direction at the moment of the stopping, the roller 29 is reversed, and the sheet 67b is surely stopped in a condition where the sheet 67b is slightly pushed back in an anti- feeding direction due to the reversal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The invention relates to a facsimile, a copying machine,
The present invention relates to a sheet feeding device used in a computer, a word processor printer, or the like, and a double feed preventing device for a sheet feeding device such as a card or film feeding device.

[0002]

2. Description of the Related Art Conventionally, in a sheet feeding device as described above, as a device for preventing a plurality of sheets from being fed in an overlapping state, a rubber made of rubber is elastically adjusted by a spring on a sheet feeding surface of a roller. However, it is known that when two or more sheets are fed in elastically, the sheet ends of the second and subsequent sheets are brought into contact with the rubber rubber surface and stopped.

[0003]

However, in the above structure, since the contact surface between the roller and the rubber is worn, it is always necessary to make a delicate adjustment of the spring tension, and the improper adjustment causes double feeding or improper feeding. In addition to the problems such as the occurrence of the above, there is a defect that the rubber mounting structure is complicated and the cost is high. The present invention intends to provide a sheet double feed prevention device which solves these drawbacks.

[0004]

The device of the first invention in the present invention for solving the above problems is a drive roller 2
8, the driven roller 29 is pivotally supported so that it can be moved in and out of contact with the roller 8, and the end of the sheet 67 is fed to the circumferential contact surfaces of both rollers 28, 29.
As the rollers 28 and 29 rotate, the ends of the sheet 67 are held between the rollers 28 and 29 so that both rollers 2
In the device for feeding the sheet 67 in the rotation direction of 8, 29,
A coil spring 58 is built in between the driven roller 29 and the roller 27 axis, and the spring 5 is opened so that the roller can be rotated in the loosening direction only when the sheet feeding direction is rotated.
It is characterized in that a regulating portion 64 for regulating the rotation of one end of 8 is provided. Further, in the second invention, the drive rollers 9, 21, 28 and the driven rollers 11, 2 are provided in the frame 2.
The mechanism for rotating the rollers in interlocking manner so as to rotatably rotatably rotate the rollers 3, 29 is characterized in that the drive rollers 28, 29 on the sheet supply side are structured to have the above characteristics.

[0005]

When one sheet is caught in the feeding direction between the driving roller 28 and the driven roller 29, both rollers 28 and 29 hold the sheet 67 and perform feeding operation as the rollers rotate. At this time, the spring 58 in the driven roller 29 is twisted in the loosening direction of the coil diameter by the rotational force from the roller peripheral surface side, so that it freely rotates between itself and the roller shaft 27 side.

On the other hand, when the ends of two or more sheets 67a and 67b are fed between the rollers 28 and 29,
Since one sheet 67b comes into contact with the driven roller 29 and pushes the driven roller 29 away from the drive roller 28, the rotational force is not transmitted, slipping occurs between the sheets 67a and 67b, and only the sheet 67a in contact with the drive roller 28 side. Is sent, and the other sheet 67b is stopped. At this moment, when the spring 58 in the driven roller 29 stops, it returns to the elastic state in which the spring 58 opened in the loosening direction is elastically restored in the tightening direction. The sheet 67b is rotated in the reverse direction, and due to the reverse rotation, the sheet 67b contacting the driven roller 29 side is surely stopped in a state where it is slightly pushed back in the counter feeding direction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of the present invention, in which a sheet feeding device 1 is a paper feeding device to be attached to various office equipments, and a front side end of a frame 2 having channel-shaped cross sections having side walls 3 at both ends. A motor 4 is attached to the. A driving roller 9, 21, 28 made of rubber and driven rollers 11, 23, 2 are made between the side walls 3, 3 with a predetermined distance from the front end side.
9 are roller shafts 8, 19, 27 and 12, 22,
31 are rotatably supported in three pairs, and the rollers 28, 29, 21, 23, 9 and 11 respectively rotate and hold the sheet 67 between the rollers, and sequentially feed it forward. Acts like.

The roller shafts 8, 19, 27 on the side of the drive rollers 9, 21, 28 are the output gear 6 of the motor 4 and the drive gears 7, which are attached to the roller shafts 8, 19, 27 on the drive side, respectively.
17, 18, 26 and the relay gear 1 axially supported between them
3, 14, 16 and 24 are rotationally driven in the same direction (sheet feeding direction). Among them, the driven side roller shafts 22 and 31 are, as shown in FIG.
2 is horizontally supported by arms 34 and 36 which are bent and projected downward at the front and rear ends of a plate-shaped horizontally long top plate 33,
The lower end of the front arm 34 is pivotally supported by the roller shaft 19 of the drive roller 21 in the side plates 3 and 3 so that the rear end of the frame can swing. The feeding frame 32 has a structure in which a spring 37 is stretched between the feeding frame 32 and the side plates 3 and 3 so that the driven roller 39 at the rear portion is always elastically pressed against the driving roller 28.

At the rear portion of the frame 2, a sheet feed plate 41 for stacking and stacking sheets (paper sheets) and sequentially supplying them between the rollers 28 and 29 is provided with a locking tool (pin) projecting on the side plates 3 and 3 side.
It is inserted so as to be supported by 42. A notch 40 for accommodating the drive roller 28 at the time of inserting and setting is formed in the center of the lower end of the paper feed plate 41. A plate-shaped sheet guide 43 for guiding the sheet 67 sent from the rollers 28 and 29 to the next relay rollers 21 and 23 side is fixedly provided between the drive rollers 28 and 21 via a support 43 ′. Between the rollers 21 and 9, the roller 21,
A sheet guide 44 that guides the sheet 67 sent from between 23 between the rollers 9 and 11 is fixedly attached to the frame 2 side by a support 48, and the sheet 67 is provided between the lower plate 47 and the upper plate 46 in the front-rear direction. It is sent forward through the open guide portion 45.

3 and 4 show the structure of the driven roller 29 of the rearmost sheet catching rollers 28 and 29.
A fixed drum 51 made of synthetic resin is fitted to the roller shaft 31 fixedly attached to the frame 1 side. The fixed drum 51 has a flange-shaped spring receiver 5 from the left end.
4, sleeve 52 that serves as a spring core, pin 5 on the cylinder
3 are sequentially formed, a large number of split grooves 57 are cut at the tip of the insertion pin 53 so that the tip of the pin can be elastically opened and closed, and a fixing claw 56 is provided at the outer periphery of the tip. ing. The rubber peripheral roller 66 is fitted on the outer periphery of the cylindrical movable drum 61 made of resin, and has a cylindrical shape into which the pin 53 of the fixed drum 51 is rotatably inserted and set inside the inner right end thereof. A sleeve 62 that serves as a spring core is integrally provided between the inner periphery of the movable drum 61 and a spring accommodating space 63, and a protrusion-like restricting portion 64 is protruded at the bottom of the spring accommodating space 63. ..

Reference numeral 58 denotes a coil-shaped spring made of a synthetic resin such as polycarbonate which is fitted onto the sleeves 52 and 62 in a state where the sleeve 52 and the sleeve 62 are butted against each other. With the sleeve 62 inserted and set, the drums 51 and 61 are fitted around the outer circumferences of the drums 51 and 61 in a lightly elastic state, and are housed in the movable drum 61. By using the spring 58 having a relatively high coefficient of friction as described above,
The operation described later becomes reliable.

In the present embodiment, the spring 58 is formed in a left-handed winding, and when the driving roller 28 is rotated in the direction of arrow a (FIG. 3) in a united state as shown in FIG. Since the roller 66 and the movable drum 61 rotate in the directions of the arrows b and c, the restriction portion 64 pushes the spring end 58a in the direction of the arrow d (the loosening direction of the spring 58) so that the spring 58 is located between the peripheral surface of the sleeve 62. Since a slight gap is generated in the peripheral surface, the frictional force is not generated between the peripheral surface and the peripheral surface, and the peripheral surface rotates while sliding. As a result, the driven roller 29 rotates in contact with the driving roller 28. At this time, both rollers 28,
Even if one sheet is interposed between 29, the rotation of both rollers is not affected, and the sheet 67 is fed as shown in FIG.

However, when two or more sheets 67a and 67b are caught between the rollers 28 and 29 in the above rotating state as shown in FIG. 5B, the elastic force of the spring 37 or the roller 2
9 and the roller 29 against the own weight of the feeding frame 32.
Is separated from the roller 28 and the sheets 67a, 67
Since a slip occurs between b, the rotational force of the drive roller 28 is not transmitted to the driven roller 29 side and the driven roller 2
The rotation of 9 stops. 2 by stopping the roller 29
The sheet 67 of the first sheet is not always stopped, but the accumulated force of the spring, which has been pressed by the restricting portion 64 in the direction in which the spring diameter is open (loosening direction), is released, so that the spring diameter is tightened in the direction in which the spring diameter is tightened. The spring end 58a is pushed out in the direction opposite to the arrow d, and as a result, the movable drum 61 and the peripheral roller 66 both momentarily rotate in the direction opposite to the arrow b via the restricting portion 64. This reverse rotation is a slight amount and elastic rotation. By such reverse rotation of the rollers, the second sheet 67b is pushed back by a slight amount in the anti-feed direction, and double feeding is prevented. In the illustrated example, the spring 58 is stored in the loosening direction and an example in which the restricting portion 64 acts or is acted when the stored force is released is described. However, in addition to this example, the spring 58 and the sleeve 62 are described.
The frictional force at the time of fitting is properly adjusted so that the roller 29 rotates freely in the feed direction, and the spring 5 rotates in the reverse direction.
It is also possible to adopt a structure in which the rotation of the roller 29 is restricted by the tightening operation of 8, and in that case the restricting portion 64 is unnecessary.

[0014]

According to the present invention configured as described above,
Compared to the conventional type that has a torque limiter on the feed roller and presses the rubber, it prevents the double feeding of sheets more reliably, and has a simple structure, low cost, easy maintenance, and a service life. Also has the advantage of becoming longer.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a sheet feeding (sheet feeding) device in a printer.

FIG. 2 is a side sectional view of the sheet feeding device.

FIG. 3 is an exploded perspective view of a main portion of a double feed prevention device.

FIG. 4 is a sectional view of a driven roller of the double feed prevention device.

5A and 5B are cross-sectional views of the feed roller in a normal sheet feeding state and a double feeding prevention state.

[Explanation of symbols]

 2 frame 9,21,28 drive roller 11,23,29 driven roller 27 roller shaft 58 spring 64 restriction portion 67 sheet

Claims (2)

[Claims] 1. A driven roller (29) is rotatably supported by a drive roller (28) such that the driven roller (29) can be moved toward and away from the driven roller (28).
The end of the sheet (67) is fed to the circumferential contact surface of (29), and the sheet (6) is rotated as the rollers (28) and (29) rotate.
7) A device for feeding a sheet (67) in the rotational direction of both rollers (28), (29) by holding the end between rollers (28), (29), wherein said driven roller (2)
Coil spring (58) between 9) and roller shaft (31)
A sheet feeding device in which a roller (29) and a roller shaft (31) are connected via a coil spring (58) so that the roller can be elastically opened in the loosening direction and rotated when the sheet feeding direction is rotated. Double feed prevention device. 2. A drive roller (9) in the frame (2),
(21), (28) and driven rollers (11), (23),
A mechanism for rotating each roller by rotatably rotatably rolling the (29) and driving rollers (28), (29) on the sheet feeding side having the structure of claim 1 Prevention device.