JPH0859003A - Friction separating roller paper feed device - Google Patents

Abstract

PURPOSE: To provide a friction separating roller paper feed device which can change contact pressure of a reverse roller with a feed roller by eliminating limitation in the diameter of a driven gear or a torque limiter. CONSTITUTION: A torque limiter 4 and a driven gear 5 are integrated with each other, which are mounted onto the shaft 3a of a reverse roller 3 as a torque limiter unit 10. The torque limiter unit 10 is disposed on the opposite side to the reverse roller 3 with a side plate 20 serving as a boundary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a feed roller that rotates in the paper feed direction, and a reverse roller that is in contact with the feed roller and that applies a constant torque in the opposite direction to the feed roller via a torque limiter. The present invention relates to a friction separation roller sheet feeding device that separates and feeds only a sheet that is in contact with a feed roller among sheets that have been fed by being fed between these rollers.

[0002]

2. Description of the Related Art A friction separating roller sheet feeding device of the above type is
It is publicly known and is provided for feeding transfer sheets and feeding documents in printers, copiers, facsimiles, printers and the like, an example of which is shown in FIGS. 6 and 7.

In FIGS. 6 and 7, when a paper feed command is issued, the pickup roller 1 and the feed roller 2 rotate in the paper feed direction, and a constant torque is applied in the opposite direction via the torque limiter 4. Reverse roller 3
Does not rotate in reverse, but rotates with the feed roller 2. By rotating the pickup roller 1, the uppermost sheet of the sheet bundle is fed into the nip between the feed roller 2 and the reverse roller 3. At this time, when one sheet is fed, the sheet is fed as it is, and when two or more sheets are fed, the sheet is separated and only the uppermost sheet contacting the feed roller 2 is fed.

The principle of such separation and feeding is that when the number of fed sheets is one, as shown in FIG. 8A, the feeding force of the feed roller 2 is F ₁ , and the friction coefficient between the feed roller 2 and the sheet. Is μ _R , the contact pressure of the reverse roller 3 to the feed roller 2 is P, and the returning force by the torque of the torque limiter 4 is T, then F ₁ = μ _R · P> T, and the reverse roller 3 is It rotates in the same direction as the rotation.

When the number of fed sheets is two, as shown in FIG. 8B, the feeding force of the feed roller 2 is F ₂ , the friction coefficient between sheets is μ _P , and the weight of one sheet is Assuming m, the condition for feeding the upper paper is F ₁ = (μ _R −μ _P ) P The condition for returning the lower paper is T> μ _R · P + μ _P · m + μ _P · 2
Since m T> μ _R · P + 3 μ _P · m, the sheets can be reliably separated and fed into the machine one by one.

As shown in FIG. 7, the reverse roller 3 is provided with a driven gear 5 as a drive input gear thereof and a torque limiter 4 in the vicinity thereof, and both support a shaft 3a of the reverse roller 3 not shown. It is located inside the side plate.

In the conventional friction separating roller sheet feeding device, the contact pressure P of the reverse roller 3 to the feed roller 2 is attached to the arm 7 which is rotatable about the shaft 3a of the reverse roller 3 about the shaft 6 as a fulcrum. It is obtained by the elastic force of the spring 8 locked to the arm 7. Therefore, it is extremely difficult to change the contact pressure P thus obtained.

[0008]

However, since the driven gear 5 and the torque limiter 4 are arranged inside the side plate in the above-mentioned conventional friction separation roller sheet feeding device, the diameter must be smaller than that of the reverse roller. First, it was necessary to increase the precision of the parts. In particular, when the torque limiter 4 is made to have a small diameter to obtain a predetermined torque, the torque limiter 4 is lengthened in the axial direction, resulting in a high manufacturing cost.

Further, since the contact pressure P is always constant in the above-mentioned conventional friction separating roller sheet feeding device, the paper quality of the sheet,
There is also a problem that non-feeding and double feeding frequently occur depending on paper thickness and moisture absorption state.

The present invention solves the above-mentioned conventional problems, eliminates the limitation of the diameters of the driven gear and the torque limiter, and provides a friction separating roller sheet feeding device capable of varying the contact pressure of the reverse roller to the feed roller. It is intended to be provided.

[0011]

In order to achieve the above object, the present invention is directed to a feed roller which rotates in the paper feeding direction, and a feed roller which is abutted against the feed roller and is fixed in a direction opposite to the feed roller via a torque limiter. A friction separation roller paper feed that has a reverse roller to which torque is applied and separates and feeds only the paper that is in contact with the feed roller In the apparatus, the roller shaft of the reverse roller is rotatably supported by the side plate, and a driven gear for transmitting the drive to the reverse roller is arranged on the opposite side of the reverse roller with the side plate as a boundary.

Further, in order to achieve the above object, the present invention provides a torque limiter unit in which the torque limiter and the driven gear are integrated, and the torque limiter unit is opposite to the reverse roller with the side plate as a boundary. It is characterized by being placed in.

Further, in order to achieve the above-mentioned object, the present invention forms the driven gear wider than the driving gear meshing with the gear, and the driving gear moves in the width direction with respect to the driven gear. The feature is that it is provided.

Further, in order to achieve the above-mentioned object, the present invention is characterized in that an operating member for operating the movement of the drive gear is provided, and an operating portion of the operating member is arranged on an exterior portion.

[0015]

According to the above construction, since the driven gear for transmitting the drive to the reverse roller is arranged on the opposite side of the reverse roller with the side plate as a boundary, avoiding that the driven gear is restricted by the diameter of the reverse roller. You can

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2 are a sectional view and a perspective view showing a main part of a friction separating roller sheet feeding device according to the present invention.
The same members as those in FIGS. 6 and 7 are designated by the same reference numerals. 1 and 2, the torque limiter 4 and the driven gear 5
Are integrated and attached to the shaft 3a of the reverse roller 3 as the torque limiter unit 10. The torque limiter unit 10 of the present embodiment, as shown in FIG.
A magnet 10 is fixed to the driven gear 5 and rotatably mounted on the reverse roller shaft 3a. The magnet 10 is covered with a cover 12 whose rotation direction is restricted via a reverse roller shaft 3a and a pin 11, and a magnetic body 13 is fixed to the inner surface side of the cover 12, that is, the surface facing the magnet 10. , Magnetic body 13 and magnet 10
An appropriate gap is formed between and. The torque limiter unit 10 uses a magnetic force to non-contactly apply a rotational force from the driven gear 5 to the reverse roller 3.

The torque limiter unit 10
Is arranged on the opposite side of the reverse roller 3 with the side plate 20 as a boundary. Therefore, since the diameter and form of the torque limiter unit 10 are not influenced by the diameter of the reverse roller 3 at all, the size can be improved in productivity, and the cost can be reduced. Since 2 is not influenced by the torque limiter 4 and the driven gear 5, the diameter of these rollers can be reduced to make the paper feeding device compact.

By the way, the contact pressure P of the reverse roller 3 to the feed roller 2 is generated by the meshing of the driven gear 5 and the drive gear 22, and the rotational force due to the load torque of the torque limiter unit 10 is shown with the bearing 21 of the side plate 20 as a fulcrum. 1
The rotational force is applied in the direction of the arrow. That is, by selecting the meshing position of the drive gear 22 with the driven gear 5, the rotational force in the arrow direction shown in FIG. 1 can be applied. Therefore, the contact pressure P of the reverse roller 3 to the feed roller 2 is obtained by the cooperation of the meshing rotational force of the gear and the pressure of the arm 7 biased by the spring 8 with the shaft 6 as a fulcrum. The arm 7 is mounted on the reverse roller shaft 3a via a bearing (not shown), and the direction of the rotational force due to the engagement of the driven gear 5 and the drive gear 22 is the direction of this bearing, and the reverse roller 3 is the feed roller. It is preferable to guide so as not to deviate from the direction in which it is pressed against 2.

FIG. 4 is a sectional view showing another embodiment of the present invention. In this embodiment, the driven gear 5 is formed wide in the axial direction of the reverse roller, and the drive gear 22 is provided on its shaft 22a. Although it is restricted in the rotation direction, it is mounted so as to be movable in the axial direction. Therefore, the drive gear 2
2 is movable in the axial direction while maintaining meshing with the driven gear 5.

Further, the exterior plate 2 of the device provided with the present paper feeding device
3 is provided with a guide arm 25 attached to the elongated hole 24 so as to be movable in the extending direction, and one end of the guide arm 25 has an adjusting knob 26 fixed to the outside of the exterior plate 23.
An arm portion 27 straddling the drive gear 22 is formed at the other end of the guide arm 25, the adjusting knob 26 and the arm portion 27 are connected by a screw 28, and the guide arm 25 is formed in the long hole 24 by loosening the screw 28. It can move in the extending direction. Further, the extending direction of the elongated hole 24 is parallel to the axial direction of the shaft 22a, and the length of the extending direction is set to be substantially equal to the width of the driven gear 5.

In the sheet feeding device having the above structure, the adjusting knob 26 is loosened to move in the arrow direction of FIGS.
The drive gear 22 is moved via the arm portion 27 of the guide arm 25 between the position shown by the solid line and the position shown by the chain line in FIG. 4, and the meshing position of the drive gear 22 and the driven gear 5 is changed. At this time, in the meshing position of both gears, the length from the bearing 21 of the side plate 20, which is the fulcrum of the rotational force due to the meshing, changes, and the position from the bearing 21 shown in FIG. From the position indicated by the solid line with the length from to L1, L2> L1. Therefore, since L2 is longer than the fulcrum than L1, the moment force becomes large and the contact pressure P of the reverse roller 3 to the feed roller 2 is increased.
Grows larger.

Thus, the contact pressure P of the reverse roller 3 with respect to the feed roller 2 can be varied. A large contact pressure P is suitable for feeding thick paper, and a small contact pressure P is suitable for feeding thin paper. . Therefore, as shown in FIG.
3 is provided with indications of thin paper and thick paper, and the user appropriately drives the driven gear 5 of the drive gear 22 by using the adjusting knob 26 as an operation unit.
It is possible to adjust the contact pressure P by changing the meshing position with the. The guide arm 25 may be moved by using a motor or the like instead of the manual adjustment knob 26. At this time, the operation unit (switch) is preferably arranged on the operation panel or the like which is the exterior part.

[0024]

According to the first aspect of the present invention, since the gear drive portion is brought outside the side plate to maintain the basic separating function, the feed roller is influenced by the torque limiter and the gear. Without it, it can be smaller or larger. On the contrary, the torque limiter and the gear drive unit can be set to have appropriate sizes regardless of the feed roller. As a result, the torque limiter can be made large enough for productivity,
There are cost advantages. Further, the feed roller diameter can be reduced to form a compact sheet feeding / conveying path, which has an effect of contributing to downsizing of an image forming apparatus having a multi-stage sheet feeding device.

According to the structure of claim 2, in addition to the effect of claim 1, by integrating the torque limiter and the driven gear, cost reduction such as machining cost, assembly cost and parts cost can be obtained.

According to the third aspect of the invention, the width of the driven gear can be widened to adjust the meshing position with the drive gear, whereby the contact pressure of the reverse roller to the feed roller can be adjusted. Since the device itself is simple and compact, the device can be downsized.

According to the structure of claim 4, an adjusting portion for adjusting the contact pressure of the reverse roller to the feed roller can be provided outside the exterior plate with a simple mechanism, and the user can adjust the contact pressure in consideration of paper quality and the like. It can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a friction separation roller sheet feeding device according to the present invention.

FIG. 2 is a perspective view showing a main part of a friction separation roller sheet feeding device according to the present invention.

FIG. 3 is a sectional view of a torque limiter unit of the friction separation roller sheet feeding device according to the present invention.

FIG. 4 is a sectional view showing another embodiment of the friction separating roller sheet feeding device according to the present invention.

FIG. 5 is an explanatory diagram of the adjusting knob.

FIG. 6 is an explanatory diagram showing an overall configuration of a conventional friction separation roller sheet feeding device.

7 is a perspective view of a main part of FIG.

8A and 8B are schematic diagrams for explaining the principle of the double-feed separating action.

[Explanation of symbols]

 2 Feed roller 3 Reverse roller 4 Torque limiter 5 Driven gear 10 Torque limiter unit 20 Side plate 22 Drive gear 26 Adjustment knob

Claims (4)

[Claims] 1. A feed roller that rotates in a paper feed direction, and a reverse roller that is in contact with the feed roller and that applies a constant torque in a direction opposite to the feed roller via a torque limiter. In a friction separation roller sheet feeding device that separates and feeds only the sheet that is in contact with the feed roller from other sheets among the sheets that have been fed in a double-feeding manner, the roller shaft of the reverse roller is rotatable on the side plate. A sheet feeding device, wherein a driven gear that is supported and transmits a drive to the reverse roller is arranged on the opposite side of the reverse roller with the side plate as a boundary. 2. The friction separation roller sheet feeding device according to claim 1, further comprising a torque limiter unit in which the torque limiter and the driven gear are integrated, and the torque limiter unit is a reverse roller with the side plate as a boundary. A sheet feeding device, which is arranged on the opposite side of the sheet feeding device. 3. The friction separation roller sheet feeding device according to claim 1, wherein the driven gear is formed wider with respect to a drive gear meshing with the gear, and the drive gear is different from the driven gear. A sheet feeding device, which is provided so as to be movable in the width direction. 4. The friction separating roller sheet feeding device according to claim 3, wherein an operating member for operating the movement of the drive gear is provided, and an operating portion of the operating member is arranged on an exterior portion. Paper feeding device.