JPH08208068A - Paper sheet feeding roller - Google Patents

Abstract

PURPOSE: To provide a paper sheet feed roller capable of keeping a good sheet transfer function over a long term, and preventing a sheet from being caught by a sheet guide or the like at a sheet transfer process. CONSTITUTION: This paper sheet feed roller has a roller member 4 made of an elastic material such as rubber and fixed to bosses 3 formed at both sides of a sheet corrugation preventing section 2. The outer diameter d2 of the section 2 is made larger than the outer diameter D of the member 4, and formed to be equal to or larger than the maximum diameter D0 of the bosses 3. Also, the center outer diameter d1 of the section 2 is made larger than the outer diameter d2 of both ends thereof. As a result, even when the member 4 is worn and the outer diameter thereof is reduced as a result of a long-term service, the member 4 does not contact a sheet, because the section 2 has a reduced outer diameter at both ends. Thus, the function of the member 4 does not drop. Also, as the center outer diameter d1 of the section 2 can be formed to be large, a sheet traveling through a feed roller 1 can be properly prevented from being corrugated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed roller used in electrophotographic copying machines, printers and the like, and in particular, roller members formed of an elastic body such as rubber are formed on both sides of a paper corrugation preventing portion. The present invention relates to a paper feed roller having a structure fixed to each boss portion.

[0002]

2. Description of the Related Art In a device such as an electrophotographic copying machine or a printer, a plurality of paper feed rollers are used in a paper feeding device or the like as described in, for example, Japanese Patent Laid-Open No. 2-231324. Has been. FIG. 5 shows a general structure of a sheet feeding device of the above-described conventional apparatus, in which the sheet feeding device 10 is arranged so as to face the outlet side of the upper end portion of the sheet feeding tray 11. The paper tray 11 has a large number of paper sheets P.
Is housed. The paper P in the paper feed tray 11 is pushed upward from below the paper feed tray 11 by a push-up mechanism (not shown), and the upper surface of the uppermost paper P is located above the paper feed tray 11. Is placed at a position where it comes into contact with.

The pickup roller 12 is rotatably driven in a direction in which the paper P is sent out from the paper feed tray 11 in conjunction with a feed roller 13 arranged at a downstream portion thereof, and is swingable around a feed roller shaft 13A. A pickup roller shaft 12A is rotatably provided on the swinging end of the pickup roller support frame 22 supported by. A pickup roller gear 20 is fixed to a side portion of the pickup roller 12 so as to rotate integrally with the pickup roller 12, and the pickup roller gear 20 includes a pickup roller support frame 22.
Further, the idle gear 24 is meshed with the idle gear 24 which is rotatably supported by the idle gear shaft 24A. The idle gear 24 meshes with a feed roller gear 21 provided so as to rotate integrally with the feed roller 13, and the pickup roller 12 and the feed roller 13 are rotationally driven in the same direction.

The rotation of the feed roller 13 and the pickup roller 12 is performed by a rotary drive source connected to the feed roller shaft 13A. The pickup roller support frame 22 is operated by a mechanism (not shown) so that the pickup roller 12 contacts the upper surface of the paper P when the paper P is fed from the paper feed tray 11, and
When the paper feed tray 11 is pulled out from the apparatus main body, the pickup roller support frame 22 is configured to retract above the paper feed tray 11 and release the pickup roller 12 from the upper surface of the paper P.

A retard roller 17 is arranged at a position in contact with the lower surface of the feed roller 13. The retard roller 17 is rotatably supported by a retard roller shaft 17A on a swing end of a retard roller support frame 18 that is swingably attached to a swing shaft 18A supported on the apparatus main body side. The retard roller 17 is provided with a retard roller spring 19 stretched between a spring mounting portion 18B provided on the retard roller support frame 18 and a spring fixing portion 27 provided on the apparatus body side. 17 is always urged in such a direction as to come into contact with the feed roller 13.

As shown in FIG. 6, the retard roller 1 is used.
7 is connected to the retard roller shaft 17A via a torque limiter 32, and the retard roller shaft 17A is also connected to the retard roller shaft 17A.
Is rotated clockwise in FIG. 5 by a rotary drive source (not shown). The torque limiter 32 limits the torque transmitted between the retard roller 17 and the retard roller shaft 17A to a certain value. When the load torque of a certain value or more is applied to the retard roller 17, the retard roller 17 The structure is such that it slips with the retard roller shaft 17A. By providing the torque limiter 32, the feed roller 1 is provided for the paper P sent from the paper feed tray by the pickup roller.
A separating action is performed between the roller 3 and the retard roller 17. That is, when only one sheet P is fed between the feed roller 13 and the retard roller 17, the load torque applied to the retard roller 17 by the frictional force between the feed roller 13 and the sheet P is the torque. Since it is set to be larger than the transmission torque of the limiter 32,
The retard roller 17 causes friction between the retard roller 17 and the lower surface of the paper P to cause the paper P to move.
Of the sheet P, the sheet P is rotated counterclockwise in FIG. 5, and the sheet P is arranged on the downstream side thereof.
Sent to.

On the other hand, when the pickup roller 12 simultaneously pulls out a plurality of sheets of paper P from the paper feed tray 11, the plurality of sheets of paper P overlap between the feed roller 13 and the retard roller 17. Intrude in In this case, the frictional force between the overlapping sheets P causes the feed roller 13 and the retard roller 17 to rotate.
Is smaller than the frictional force between the sheet P and the sheet P, only the sheet P that is in direct contact with the feed roller 13 is sent to the downstream side. Since the resistance torque applied to the retard roller 17 by the frictional force between the sheets P is smaller than the transmission torque of the torque limiter 32, the retard roller 17 rotates clockwise, which is the same direction as the retard roller shaft 17A, The paper P not in direct contact with the feed roller 13 is returned to the paper feed tray 11 side by the rotation of the retard roller 17, and the paper P is prevented from being double-fed to the paper transport path 25.

The sheet feeding device 10 configured as described above.
The paper feed rollers constituting the pickup roller 12, the feed roller 13, the retard roller 17 and the like used in the above are used for the conveyance width of the maximum size of the paper P as shown in FIG. , Are arranged at one side, and are configured to be compatible with a plurality of types of paper sizes. The feed roller shaft 13A that supports the feed roller 13 and the pickup roller support frame 22 to which the pickup roller 12 and the like are attached is attached to a mounting frame 29 fixed to a main body frame 28, a bearing 30,
A feed roller and a pick-up roller are supported via 30 and are provided so as to project laterally of the mounting frame 29 in a cantilever state. Further, the retard roller shaft 17A provided with a retard roller 17 arranged so as to face the feed roller 13 is supported by the retard roller support frame 18 via bearings 31, 31, and Like the feed roller and the pickup roller, the roller 17 is also provided so as to project laterally from the retard roller support frame 18 in a cantilevered state.

As shown in FIG. 6, the cantilevered support structure of each paper feed roller has a feed roller 13 and a retard roller 1.
The rigidity is lower than that of a structure in which the feed roller shaft 13A and the retard roller shaft 17A are supported by bearings from both sides of No. 7, and the directional stability during conveyance of the paper P is inferior. However,
Since a general copying machine, printer, or other device has a structure for correcting the attitude of the paper P on the downstream side of the paper feeder, it is not necessary to position the attitude of the paper P with high precision in the paper feeder. In addition, if the structure is such that the paper feed rollers such as the feed roller and the retard roller are supported by bearings on both sides in order to increase the rigidity, the manufacturing cost increases and at the same time,
Since it is difficult to miniaturize the apparatus, the cantilever support structure of each paper feed roller as described above is often adopted.

[0010]

The above-mentioned sheet feeding device 10
In general, a paper feed roller 1 as shown in FIG. 7 is used. The paper feed roller 1 includes a boss portion 3 on both sides of a cylindrical paper corrugation prevention portion 2 formed of synthetic resin or the like.
And a roller member 4 formed on the outer peripheral surface of the boss portion 3 with an elastic body such as rubber that contacts the paper P.
And a flange portion 3A for preventing the roller member fixed to the boss portion from coming off by being brought into contact with the end surface of the roller member 4 on the side portion of the boss portion 3.
The paper corrugation prevention unit 2 provided on the paper feed roller 1 prevents the paper P from corrugating in the width direction between the two roller members due to the pressure applied from the roller member 4 to the paper P when the paper P is conveyed. It is provided to do so. The paper feed roller 1 having the above-described configuration has an outer diameter D of the roller member 4.
However, it is formed larger than the outer diameter d of the paper corrugation preventing portion 2 and the outer diameter D0 of the flange portion 3A by a predetermined dimension.

As shown in FIG. 6, the paper feed roller 1 is
When used as the pickup roller, the feed roller, and the retard roller in the cantilevered supporting state shown in FIG. 6, the contact with the sheet P acting on the roller member 4 on the side near the mounting frame 29 and the retard roller supporting frame 18 is performed. The pressure received from the surface side becomes larger than the pressure applied to the roller member on the far side, and the outer peripheral surface of the roller member of the paper feed roller is worn to the state shown in FIG. 8 after long-term use. That is, on the side where the contact pressure of the roller member 4 is large, the roller member 4 having the outer diameter D at first is worn down to the outer diameter D ′ after being used for a long period of time. When the outer diameter D ′ wears to the same extent as the outer diameter d of the paper corrugation prevention unit 2, the paper corrugation prevention unit 2 made of synthetic resin comes into contact with the paper P, and the paper The frictional force for carrying P is reduced, and the paper carrying function of the paper feed roller 1 is reduced. Therefore, in order to maintain the paper transport function of the paper feed roller 1 for a long period of time, the roller member 4 is used.
It is conceivable to increase the ratio of the outer diameter D to the outer diameter d of the paper corrugation prevention unit 2 so as to keep the abrasion of the roller member large. However, when the outer diameter ratio between the roller member and the paper corrugation prevention unit is increased, the gap formed between the paper corrugation prevention unit and the paper P becomes large, and the paper P of the paper corrugation prevention unit is conveyed when the paper P is conveyed. There is a problem that the function of preventing waving becomes smaller. In particular, when the gap becomes large, when the paper feed roller 1 having the above configuration is used as the feed roller 13 of the paper feeding device shown in FIG. 5, the rising portion 2 of the end portion of the paper guide 26 constituting the paper transport path 25 is used.
The front end of the corrugated paper is caught between the roller members 4 at 6A, which causes a paper jam.

Therefore, it is impossible to secure a large margin between the roller member 4 and the outer diameter of the paper corrugation preventing portion 2 against wear.
When there is uneven wear of the roller member 4 as described above,
There is a drawback that the life of parts of the paper feed roller is reached earlier than the life due to the change in characteristics of rubber or the like over time, resulting in much waste.

[0013]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned problems of the conventional paper feed roller, can maintain the good running property of the paper for a long period of time, and, at the time of carrying the paper, An object of the present invention is to provide a paper feed roller that can prevent paper from being caught in a paper guide or the like.

[0014]

To achieve the above object, the present invention provides a paper feed in which roller members formed of an elastic material such as rubber are fixed to boss portions formed on both sides of the paper corrugation prevention portion. It is a roller, and the outer diameters of both end portions of the paper corrugation prevention unit are formed to be smaller than the outer diameter of the roller member and not less than the maximum diameter of the outer periphery of the boss portion, and the central portion of the paper corrugation prevention unit is It is characterized in that it is formed smaller than the outer diameter.

In the structure of the paper feed roller described above, it is preferable that the paper corrugation preventing portion has a large number of collar-shaped members integrally formed so that the outer diameter gradually increases from both end portions toward the central portion. . In addition, the boss portion,
It is preferable that a flange portion is formed so as to contact the end surface of the roller member.

[0016]

In the paper feed roller of the present invention, the paper is conveyed by the roller members at both ends of the paper corrugation prevention unit, and at the same time, the corrugation generated during the conveyance of the paper is prevented by the paper corrugation prevention unit. Even if the roller member wears due to long-term use and the outer diameter of the roller member decreases,
Since the outer diameters of both end portions of the paper corrugation prevention portion are formed smaller than the outer diameter of the central portion, abrasion of the roller member can be increased, and the transport function of the paper feed roller can be maintained for a long period of time. Further, in the central portion of the paper corrugation prevention unit, the outer diameter necessary for preventing corrugation of the paper is secured, and even if the abrasion of the roller member is large, the function of preventing corrugation of the paper is not impaired.

In the case where the paper corrugation preventing portion is configured to have a large number of collar-shaped members integrally formed so that the outer diameter gradually increases from both end portions toward the center portion, When the corrugation preventing portion is integrally molded with synthetic resin or the like, distortion at the time of molding is reduced, and the manufacturing accuracy of the paper feed roller is improved. Further, when the boss portion is formed with a flange portion that comes into contact with the end surface of the roller member, the roller member is reliably fixed to the boss portion during use of the paper feed roller.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the paper feed roller 1 of the present invention.
The roller member 4 is fixed to the boss portions 3 formed at both ends of the paper corrugation preventing portion 2 similarly to the conventional one shown in FIG. Paper corrugation prevention unit 2
The boss portion 3 and the boss portion 3 can be integrally formed of a material such as a synthetic resin. In the case of the present embodiment, the boss portion 3 is integrally provided with the flange portion 3A. The flange portion 3A
Is provided so as to come into contact with the end surface of the roller member 4 and not fall off from the boss portion even if the roller member fixed to the boss portion is loosened. The paper waviness prevention unit 2 has an outer diameter of both ends reaching the end faces of both roller members 4 as d2, and the outer diameter increases linearly toward the central portion so that the outer diameter becomes d1 at the central position. It is shaped like a mountain. Also,
The outer diameter d2 of both end portions of the paper corrugation preventing portion 2 is set to be larger than the outer diameter D0 of the flange portion 3A which is the maximum diameter portion of the boss portion 3.

The paper feed roller 1 configured as described above
Is used for the feed roller 13 and the retard roller 17 of the sheet feeding device 10 shown in FIGS. 5 and 6,
Due to the difference in pressure applied to the roller members 4 on both sides, uneven wear tends to occur in the state as shown in FIG. 2 after long-term use. Then, in FIG. 2, the roller member 4 with the greater wear wears from the outer diameter D to D ′, but the outer diameter d2 at both ends of the paper corrugation prevention unit 2 becomes the outer diameter d1 at the center position. Since it is smaller than that of the conventional roller member, it has the conventional cylindrical shape shown in FIG. 7 until the outer diameter D ′ of the worn roller member 4 reaches the outer diameter d2 at both ends of the paper corrugation preventing portion 2. It takes a longer time than in the case where the paper corrugation prevention unit 2 is used, and therefore, the paper transport function of the paper feed roller 1 can be maintained for a long time. Further, since the outer diameter d1 at the center position of the paper corrugation prevention unit 2 is larger than the outer diameter d2 at both ends, the corrugation of the paper conveyed by the paper feed roller 1 between the two roller members 4 is This can surely be prevented, and as a result, it is possible to prevent the leading edge of the sheet from being caught by a sheet guide or the like located on the downstream side of the sheet feeding roller to cause a conveyance failure of the sheet.

Next, FIG. 3 shows a second embodiment of the paper feed roller of the present invention.
This embodiment is the same as that of the above-described embodiment shown in FIG. 1 except that the paper feed roller 1 of FIG. It has a configuration. In the present embodiment, since the contour of the paper corrugation prevention unit 2 does not have an angular portion, the paper corrugation prevention unit 2 can make smooth contact with the paper to prevent corrugation of the paper.

Further, what is shown in FIG. 4 shows a third embodiment of the paper feed roller of the present invention, and in this embodiment, the paper corrugation preventing portion 2 is formed by a large number of collar portions 2A. There is. The paper corrugation prevention unit 2 is integrally molded from a material such as synthetic resin so that the outer diameter gradually increases from both ends toward the center. When the sheet corrugation preventing portion 2 is formed of synthetic resin or the like, in the case of the sheet corrugation preventing portion 2 shown in FIGS. However, in the present embodiment, since the paper corrugation prevention portion 2 is formed by the large number of collar portions 2A, the material thickness in each portion is made uniform, and the shape is less likely to be deformed due to distortion during molding. ing.

Further, the paper feed roller 1 of the present embodiment has an engaging projection 6 extending axially from the flange portion 3A on one side and an axially extending projection from the flange portion 3A on the other side. The engagement piece 7 is provided. The engaging protrusion is adapted to engage with an engaging portion of a torque limiter (not shown in the figure) to which the paper feed roller 1 is drivingly connected to transmit a driving force. The paper feed roller 1 can be used as the retard roller 17 or the like shown in FIG. A retaining ring or the like is generally used for the retard roller 17 shown in FIG. 6 so as not to move in the axial direction with respect to the retard roller shaft 17A, but in order to facilitate assembly and the like. As shown in FIG. 4, in the paper feed roller 1 of the present embodiment, the projection provided inside the locking piece 7 is formed into an annular shape formed on the peripheral surface of the shaft penetrated by the paper feed roller 1. It engages in the groove to perform the function of the retaining ring.

Although the above-described embodiments have been described with reference to the examples applied to the sheet feeding device shown in FIGS. 5 and 6, the sheet feeding roller of the present invention is the pickup roller of the sheet feeding device.
Besides being applied to a feed roller, a retard roller, etc., it can be widely applied as a paper feed roller of an apparatus including various paper transport systems. Further, the shape of the paper corrugation prevention portion provided on the paper feed roller can be variously modified within a range in which the size relationship of the outer diameter dimensions of the respective portions is maintained. Furthermore, in each of the above-described embodiments, the flange portion is formed on the boss portion to which the paper feed roller is fixed, but the flange portion may be omitted.

[0024]

As described above, according to the present invention,
The outer diameter of both ends of the paper corrugation prevention portion formed between the roller members of the paper feed roller is smaller than the outer diameter of the roller member,
In addition, since the roller member is formed to have a diameter larger than the maximum diameter of the fixed boss portion, the outer diameter of the roller member becomes equal to the outer diameter of both end portions of the paper corrugation prevention unit even if the roller member of the paper feed roller is worn. Until the number of sheets reaches, it is possible to maintain a good paper transport function.

As a result, it is possible to extend the time until the service life of the parts due to wear of the roller members, and it is possible to eliminate waste due to early parts replacement.

Moreover, since the outer diameter of the central portion of the paper corrugation prevention portion is made larger than the outer diameters of both end portions, the corrugated paper causes the leading edge of the paper to be caught by the paper guide located downstream of the paper feed roller. It does not cause paper conveyance failure.

In the case where the paper corrugation preventing portion has a large number of collar-shaped members integrally formed so that the outer diameter gradually increases from both ends toward the center, the paper When the corrugation preventing portion is integrally molded with synthetic resin or the like, the distortion generated during molding is reduced, and the manufacturing accuracy of the paper feed roller can be improved. Further, by forming a flange portion that abuts the end surface of the roller member on the boss portion that fixes the roller member, the roller member is securely fixed to the boss portion during use of the paper feed roller, and there is a risk of slipping out. The reliability is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a paper feed roller of the present invention.

FIG. 2 is a diagram showing a worn state of the paper feed roller of the present invention.

FIG. 3 is a diagram showing a second embodiment of the paper feed roller of the present invention.

FIG. 4 is a diagram showing a third embodiment of the paper feed roller of the present invention.

FIG. 5 is a side view showing a schematic structure of a general sheet feeding device.

FIG. 6 is a front view showing a schematic structure of a general paper feeding device.

FIG. 7 is a diagram showing a configuration of a conventional paper feed roller.

FIG. 8 is a diagram showing a worn state of a conventional paper feed roller.

[Explanation of symbols]

1 paper feed roller 2 paper corrugation prevention unit, 2A
Collar part, 3 boss part, 3A, flange part, 4
Roller member, 10 paper feeding device, 11 paper feeding tray, 12 pickup roller, 13 feed roller, 17 retard roller, 18 retard roller support frame, 19 retard roller spring, 22 pickup roller support frame.

Claims (3)

[Claims] 1. A paper feed roller in which roller members formed of an elastic material such as rubber are fixed to boss portions formed on both sides of the paper corrugation prevention unit, respectively. The diameter of the paper is smaller than the outer diameter of the roller member and larger than the maximum diameter of the outer circumference of the boss portion, and smaller than the outer diameter of the central portion of the paper corrugation preventing portion. Feed roller. 2. The paper corrugation preventive unit according to claim 1, wherein the paper corrugation preventing unit has a large number of collar-shaped members integrally formed so that the outer diameter gradually increases from both ends toward the center. Paper feed roller. 3. The paper feed roller according to claim 1, wherein the boss portion is formed with a flange portion that abuts an end surface of the roller member.