JPH07138488A - Conductive resin composition for bearing - Google Patents

Abstract

PURPOSE:To obtain a conductive resin composition for bearings, excellent in frictional and abrasive characteristics and impact resistance even under toner- existing states such as in the developing section of a copying machine. CONSTITUTION:This resin composition is produced by adding 10-20vol.% of carbon fibers to 100vol.% of a resin composition comprising 1-30vol.% of a lubricating oil, 1-15vol.% of a norbornene elastomer as a carrier for the lubricating oil, 1-30vol.% of detal powder, and the remaining vol.% of a synthetic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for conductive bearings, and more particularly to a resin composition for oil-free conductive bearings suitable for the developing section of a copying machine.

[0002]

2. Description of the Related Art Conventionally, synthetic resins such as polyamide, polyacetal, polycarbonate, and polytetrafluoroethylene are known as resin compositions for oil-free bearings. However, when they are used with toner intervening in the developing section of a copying machine,
Toner enters the bearing, causing problems such as an increase in rotational torque and the generation of abnormal noise. As a bearing for solving such a problem, a bearing capable of holding a large amount of lubricating oil and being sufficiently used even in the presence of toner is disclosed in Japanese Examined Patent Publication No. 59-24284.
No. 59-286286 or 60-18
796. However, the bearings disclosed in these publications do not have a static electricity removing function required as a bearing for a copying machine developing section.

On the other hand, in general, there are carbon fibers, metal powders, carbon black, etc. added in order to impart conductivity to synthetic resins. Problems such as rising and abnormal noise occur.

The present invention has been made in view of the above problems of the prior art, and its object is also to provide a toner in the developing section of a copying machine.
An object of the present invention is to provide a resin composition for conductive bearings, which has excellent friction and wear characteristics and impact resistance.

[0005]

To achieve the above object, the gist of the present invention is to provide 1 to 30% by volume of lubricating oil, 1 to 15% by volume of norbornene-based elastomer as the lubricating oil carrier, and 1 to 30% by volume of metal powder and a total of 100% by volume of a resin composition containing the remaining volume% as a synthetic resin.
A conductive bearing resin composition is characterized in that 0 to 20% by volume of carbon fiber is added.

Examples of the lubricating oil include aromatic lubricating oils such as spindle oil, machine oil, dynamo oil, naphthene lubricating oil, paraffin lubricating oil or hydrocarbons, synthetic oils such as ester, polyglycol and silicone oil. Any commonly used lubricating oil can be used.

Sprayed kelmet powder or bronze powder can be used as the metal powder.

Examples of the synthetic resin include polyamide, polyacetal, polybutylene terephthalate and the like.

As the conductivity-imparting agent added to the resin composition, carbon black can be used together with carbon fiber. As the carbon fiber, roving or milled fiber form can be preferably used. The chopped strands may become fiber balls when mixed, which is not preferable.

[0010]

Function: The lubricating oil content is 1 to 30% by volume, which means 1% by volume
If it is less than 30%, the lubricity cannot be expected, and if it exceeds 30% by volume, the physical properties are deteriorated and the screwing property into the screw during molding is deteriorated.

The norbornene-based elastomer has an extremely porous structure, can hold a large amount of lubricating oil, and can absorb up to 10 volumes of lubricating oil per volume. Therefore, by blending 1 to 15% by volume of the norbornene-based elastomer with 1 to 30% by volume of the lubricating oil, the lubricating oil can be sufficiently absorbed.

The metal powder is effective in improving the coefficient of thermal expansion and thermal conductivity of the bearing and imparting conductivity, and it is necessary to add it in an amount of 1% by volume or more. Becomes brittle.

The carbon fiber is added in an amount of 10 to 20% by volume with respect to 100% by volume of the resin composition. If it is less than 10% by volume, conductivity (specific resistance of 10 ³ Ωcm or less) cannot be obtained.
This is because if the content is more than volume%, the dust resistance of the oil-containing resin is reduced and the bearing mating material may be damaged.

[0014]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to these examples. A resin bearing having an inner diameter of 6 mm, an outer diameter of 12 mm, and a length of 10 mm was prepared from the examples and comparative examples compounded as shown in Table 1 below.
A running test was conducted under the test conditions shown below, and the transition of the friction coefficient was investigated. The result is shown in FIG. In addition, Table 2 shows the mechanical properties of the examples and comparative examples. In addition,
The formulations in Table 1 show% by volume.

[Test conditions] Load = 2 kg / cm ² , speed = 10
m / min, temperature = 23 ± 2 ° C., mating material = SUS303W,
Toner = one-component toner, clearance = 10 μm, running type = journal, motion type = continuous running.

[0016]

[Table 1]

[0017]

[Table 2]

As is apparent from Table 2 and FIG. 1, since no lubricating oil was added to Comparative Examples 1 and 3,
The variation of the friction coefficient is large under the presence of the toner, and abnormal noise may occur. Further, Comparative Examples 1 and 3 are inferior in wear resistance. Furthermore, since a large amount of metal powder was added to Comparative Example 2, the Izod impact strength was low and the impact resistance was poor. On the other hand, the material according to this example has excellent conductivity, hardly changes in the coefficient of friction, has a small amount of wear, and has high Izod impact strength.

[0019]

The conductive bearing resin composition according to the present invention has excellent friction and wear characteristics and excellent impact resistance.
It can be suitably used as a conductive bearing material. In particular,
An excellent effect can be expected when used in the developing section of a copying machine.

[Brief description of drawings]

FIG. 1 is a diagram showing a transition of a friction coefficient of a bearing in a journal type running test.

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Claims (1)

[Claims] 1. A total of 1 to 30% by volume of lubricating oil, 1 to 15% by volume of norbornene-based elastomer as the lubricating oil carrier, 1 to 30% by volume of metal powder, and the remaining volume% of synthetic resin. 10 to 10% by volume of the resin composition
A resin composition for electrically conductive bearings, wherein 20% by volume of carbon fiber is added.