JP2000048873A - Earthing device for rotating shaft - Google Patents

Abstract

(57) [Summary] [Problem] To ground the rotating metal shaft,
To provide a quiet paper transport device at low cost. The problem of galling between the shaft and the leaf spring and the problem of complicated application of conductive grease were solved. A conductive gasket (11) is sandwiched between a sheet metal (9) for frame ground and a rotating metal (5). In addition, the direction of the fiber of the coating cloth of the conductive gasket is made to coincide with the rotation direction of the shaft. Further, a movement restricting portion for restricting the movement is provided at an interval wider than the width of the conductive gasket so that the conductive gasket can move in the roller rotation direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft grounding device and a sheet conveying device provided with the grounding device.

[0002]

2. Description of the Related Art In a conventional paper conveying apparatus, for example, an original conveying apparatus of an office machine such as a copying machine or a facsimile, as shown in FIG.
4, a metal sintered bearing having a conductive property is used for grounding, or a sliding resin bearing having no conductivity is used for cost reduction, while a shaft end of the metal shaft 5 or a body of the metal shaft is used. The metal plate spring 6 is urged to the portion, and is grounded to a sheet metal 9 which is a frame ground.

[0003]

However, the following problems have been encountered in the conventional paper transport apparatus in which a leaf spring is urged against a metal shaft and grounded. (1) Although the leaf spring 6 is formed in a comb-like shape and is widely pressed against the relative shaft 5 in order to improve the conductivity (FIG. 5), the processing of the leaf spring is complicated and the component cost increases. (2) The width of the comb teeth of the leaf spring 6 becomes smaller as the size of the apparatus becomes smaller, and the strength of the leaf spring is insufficient, so that it is not easy to manage parts in physical distribution. (3) If the shaft 5 rotates at a high speed or if the urging pressure of the leaf spring 6 is increased in order to increase the conductivity, a noise is generated between the shaft 5 and the metal shaft 5. In addition, when the metal shaft 5 is rotated in the reverse direction, a bite is generated between the metal shaft 5 and the leaf spring 6, which also causes abnormal noise. Therefore, complicated work such as applying conductive grease is required, and the production cost of the apparatus is increased. In addition, since the shaft 5 is accompanied by the paper transport roller 5a, the shaft 5 may need to be replaced. In this case, it is necessary to apply new grease.
The application of conductive grease by the user himself is very difficult in practice.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a conductive earthing device for a rotating shaft.
A grounding means comprising a core material formed of an elastic material and a conductive material provided around the core material, and biasing a conductive surface of the grounding means to a rotating conductive shaft surface; The other conductive surface of the means is brought into contact with a conductive member that is conductive to the frame ground of the apparatus main body and grounded.

Further, the conductive material on the surface of the grounding means is made of cloth, and the fiber direction of the cloth is made to coincide with the rotation direction of the conductive shaft.

Further, a gap is provided on both sides of the grounding means so that the grounding means is movable between the gaps.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG.
For example, a cloth made of an elastic material such as elastomer, chloroprene, or polyurethane, and a fiber formed by depositing or spraying a metal such as aluminum on the surface of a fiber containing carbon or a fiber such as nylon or polyethylene terephthalate is used as the covering material 21. FIG. 4 is a perspective view of a gasket 11 used as a grounding means.

FIG. 1 shows a paper conveying apparatus according to the present invention. 9 is a sheet metal for a frame ground of the apparatus main body, 8 is a driving motor, 15 is a driving gear, 14 is a slidable resin bearing, and 5 is a rubber roller 5a. The accompanying metal shaft 3 is a backup roller that nips the paper (sheet) S by being urged by the rubber rollers 5a by the leaf springs 4a and 4b. 1 is an upper paper transport guide, 2 is a lower paper transport guide, and a gap of about 3 mm is provided between them, and the paper S passes through this gap.

Reference numeral 11 denotes a conductive gasket, which is fixed to one rib (standing bent portion) 10 erected from the bottom plate of the housing 7 of the paper transporting device with a double-sided tape 13 and the metal shaft 5 is dropped from above. The lower side is grounded to the sheet metal 9 of the frame ground. The direction of the coating fiber of the conductive gasket 11 is made to coincide with the rotation direction of the metal shaft 5 to improve the slidability.

In this configuration, if the conductive gasket 11 is urged widely according to the length of the metal shaft 5, a sufficient grounding area can be secured, and the conductive characteristics are improved. Compared to a grounding method using a metal plate spring, conductive grease is not required, and the paper transport device can be operated without abnormal noise.

Here, the gasket means a paddle such as a fiberboard or cork used for filling a joint of a cylinder or a pipe joint, and generally means a filling or packing. Further, there is an electromagnetic wave shielding gasket that is sandwiched between gaps of the conductive casing and shields electromagnetic waves passing through the gap.

(Second Embodiment) FIGS. 2 and 3 are sectional views of a case configured to improve the durability of a conductive gasket. Two ribs (standing bent portions) 12a and 1 are provided on both sides of the metal shaft 5 at intervals larger than the width of the conductive gasket 11.
2b, an opening is provided between the ribs 12a and 12b to make the conductive metal gasket 11 come into contact with the lower metal sheet 9 for the frame ground, and the metal shaft 5 is dropped from above to make contact with the conductive gasket 5.

In this configuration, the conductive gasket 11 can move freely between the ribs 12a and 12b in accordance with the direction of rotation of the metal shaft, and when the metal shaft 5 rotates forward (FIG. 2), the conductive gasket moves rightward. It moves and moves to the left at the time of reverse rotation (FIG. 3). The durability of the conductive gasket 11 is improved as compared with the case where the same portion is always in contact with the metal shaft 5. The moving range of the conductive gasket is within a range where the contact with the metal shaft is maintained.

[0014]

As described above, according to the present invention,
The grounding of the rotating conductive shaft can be performed without the necessity of abnormal noise or grease application, so that the structure can be constructed at a lower cost as compared with a conventional metal plate spring contact method or a grounding method using a sintered bearing.

Furthermore, if the direction of the fiber and the direction of rotation are matched, the deterioration of the conductive gasket coating can be suppressed, and the sliding load on the metal shaft can be reduced.

[0016] If it is further movable, the durability of the conductive gasket can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a cross-sectional view of a third embodiment.

FIG. 4 is a diagram of a conventional conductive gasket.

FIG. 5 is a perspective view of a conventional paper transport apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 upper paper transport guide 2 lower paper transport guide 3 backup roller 4 leaf spring 5 paper transport roller shaft 6 ground leaf spring 7 paper transport device frame 8 motor 9 frame ground sheet metal 10 rib 11 conductive gasket 12 rib 14 bearing 15 gear

Claims (5)

[Claims] 1. A grounding device for a rotating shaft, comprising: a core member formed of an elastic material; and a grounding means configured by providing a conductive material around the core material. A grounding device for a rotating shaft, characterized in that the surface is urged against the rotating conductive shaft surface, and the other conductive surface of the grounding means is brought into contact with a conductive member which is conductive to the frame ground of the device body to be grounded. . 2. The earthing device for a rotating shaft according to claim 1, wherein the conductive material on the surface of the earthing means is made of cloth, and the fiber direction of the cloth and the rotating direction of the conductive shaft are matched. 3. A gap is provided on both sides of the grounding means,
3. The rotating shaft grounding device according to claim 1, wherein the grounding means is configured to be movable between the gaps. 4. A sheet conveying device comprising: a roller supported by a rotating conductive shaft; and the rotating shaft grounding device according to claim 1. 5. The sheet conveying device according to claim 4, further comprising a roller pressed by said roller.