JP3300521B2 - Conductive rubber roller and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roll for applying an electric potential of a predetermined polarity to a member to be charged such as a photosensitive drum or a recording medium in an electrophotographic recording apparatus or the like, and a method for manufacturing the same. The present invention relates to a conductive roll capable of meeting various required characteristics and having a simplified process, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Copiers and laser beam printers
2. Description of the Related Art An electrophotographic recording apparatus widely used in general includes a drum-shaped photosensitive member (hereinafter referred to as a photosensitive drum), and forms an electrostatic latent image by charging and exposing the photosensitive drum. Then, according to the latent image on the photosensitive drum, the toner
Then, the toner on the photosensitive drum is transferred to a recording medium such as recording paper for transfer, and then the photosensitive drum is neutralized to a predetermined potential and the toner remaining on the photosensitive drum is removed. To be cleaned and then ready for recording. Further, the toner carried on the recording medium by the transfer is fixed to the recording medium by melting and pressing.
This completes a series of recording operations.

With respect to the photosensitive drum of the photosensitive drum of this electrophotographic recording apparatus, a charging roll for applying a predetermined potential to a charged area, a developing roll for conveying toner to the photosensitive drum,
A conductive roll such as a transfer roll for applying a predetermined potential to the recording medium conveyed to the transfer area, or a charge removing roll for making the charged area of the photosensitive drum after transfer uniform at a constant potential. Is usually made of at least a conductive shaft and a base made of good conductive rubber provided on the outer periphery thereof.
In some cases, the base layer is further coated with a conductive film or the like to adjust the electrical resistance of the roll and to prevent contamination of the photosensitive drum or recording medium.

[0004] Such a conductive rubber roll is obtained by balancing the above-mentioned respective uses, parts, or various required characteristics.
For example, a material having rubber elasticity with excellent compression characteristics while maintaining stable conductive performance is often required.
In addition, since each required characteristic value varies widely, when it is intended to obtain a product corresponding to each, the case where at least the aforementioned rubber layer is difficult to handle with a single layer as in the conventional case increases. I have.

[0005] On the other hand, such rolls for OA equipment, for example, are also produced by combining complicated processes, so that the above-mentioned high-mix low-volume production is inevitable. There is a problem that cost reduction is very difficult.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and uses a conductive rubber roll having a structure capable of imparting more functionality to a rubber layer. As a result, the options for meeting various required characteristics are expanded, and the production process of the roll can be simplified even a little, and the production cost of the rubber roll can be reduced. It is intended to provide a method. It is a further object of the present invention to provide a conductive rubber roll that can firmly fix the tightness and engagement between the shaft and the rubber layer without an adhesive, relatively simply and inexpensively.

[0007]

Means for Solving the Problems In order to achieve the above object, the constitution and the manufacturing method of the conductive rubber roll of the present invention are as follows. 2. A conductive rubber roller comprising a shaft and a conductive rubber layer provided on an outer periphery of the shaft, wherein the rubber layer comprises at least two layers. -It is essential that the structure be a la structure. Here, the two layers include both non-foamed rubber, both layers include foamed rubber, or both non-foamed rubber and foamed rubber. As shown, the inner rubber layer (shaft side) of the two rubber layers is a non-foamed rubber layer, and the outer layer (use surface side) is a foamed rubber layer. It is.

According to a second aspect of the present invention, in the rubber roller, the rubber layer is formed of a hollow shape (tube shape), and a shaft is later inserted into a conductive rubber roller. A conductive rubber roller having a structure of a conductive rubber roller, wherein an inner diameter of a hollow portion of the rubber layer is sufficiently smaller than a diameter of a shaft to be inserted. At this time, the inner diameter of the hollow rubber layer is 0.50 to 0.95 of the diameter of the shaft.
A degree is desirable. If the inside diameter of the rubber layer hollow portion is too small, it becomes difficult to insert the shaft, and if it is too large, the binding force with the shaft is lost.

According to a third aspect of the present invention, there is provided a method of manufacturing a conductive rubber roller comprising a shaft and a conductive rubber layer provided on an outer periphery of the shaft. A rubber roller, wherein the rubber layer comprises at least two layers, and the two layers are simultaneously and integrally extruded by a plurality of extruders into a hollow shape (tube shape). A method for producing a conductive rubber roller, comprising inserting a shaft after vulcanization.

Here, as a material of the conductive rubber constituting the rubber layer, a non-foamed or foamed rubber composition containing a conductive material can be used.

The rubber component constituting the non-foamed conductive rubber composition includes a normal rubber or styrene such as nitrile butadiene rubber, chloroprene rubber, isoprene rubber, styrene butadiene rubber, ethylene propylene rubber, isoprene rubber, polynorbornene rubber and the like. -A thermoplastic rubber such as butadiene styrene rubber (SBS) or its water additive (SEBS) can be used, and is not particularly limited. Of course, in some cases, a rubber composition that does not impart conductivity may be used.

The foamed conductive rubber is not particularly limited, but may be a mixture of ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, or the like, and a copolymer of epichlorohydrin and ethylene oxide. A rubber foam or a foam obtained by blending a conductive material with a copolymer rubber of epichlorohydrin and ethylene oxide can be suitably used.

The conductive material to be added to these rubber compositions includes conductive powders of carbon black, graphite, metal, conductive metal oxides (such as tin oxide and titanium oxide), carbon fibers, and the like. Various conductive fibers such as short fibers of metal oxide can be used.

In the present invention, the conductive rubber roller preferably has a resistance of 10 ³ to 10 ⁷ Ω, and a volume resistivity of 10 ¹ to 10 ¹³ Ωcm, preferably 10 ³ Ωcm. ¹⁰¹² is desirable that the [Omega] cm, Russia - hardness of La, the inner layer of the two layers (non-foamed rubber layer) is JIS-
In A hardness meter 20 ^{0-60 0} preferably 30 ^{0-50 0,}
In the outer layer (foamed rubber layer) is Asker -C 20 ⁰ to 70 ⁰ preferably 30 ^{0-60 0} is desirable. The thickness of the inner layer and the outer layer is 0.01 to 3 m.
m preferably 0.05 to 1 mm, outer layer 1 to 50 mm
Preferably, 2 to 10 mm is suitable.

In the conductive roller of the present invention, a single layer or a plurality of conductive layers can be coated on the base layer in order to adjust the electric resistance of the roller and prevent contamination of the photosensitive drum and the recording medium. However, the conductive layer suitably used in this case includes a temperature of 25 ° C. and a relative humidity of 50% RH.
Has a volume resistance of 1.0 × 10 ^{6 to} 1.0 × 10 ¹³
Ω · cm or a conductive adhesive layer having a volume resistance of 1.0 × 10 ¹³ Ω · cm or less at a temperature of 25 ° C. and a relative humidity of 50% RH. Further, as a method of forming the conductive film, a method of integrally molding as a single layer or a plurality of layers using a plurality of extruders in the same manner as the base layer or extruding these films and expanding the shrink tube with air to form a shrink tube. A method of forming the sheet by forming it, covering it with a base layer, and heat-treating the sheet is exemplified.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. (Embodiment) The present invention uses ethylene-propylene-diene ternary containing no foaming agent by using two extruders and using a die as shown in FIG. 3 (b) connected to each extruder. The copolymer rubber layer 2a is used as an inner layer, and an ethylene-
The propylene-diene terpolymer rubber 2b was simultaneously extruded into a hollow shape (tube shape) under the following extrusion conditions so that it became an outer layer and integrated.
The unvulcanized rubber laminated and extruded in two layers is subsequently vulcanized in a vulcanization tank using both high frequency and hot air at 250 ° C. for 10 minutes to have a 0.2 mm non-foamed rubber layer 2a inside. ,
A rubber vulcanizate having an inner diameter of 0.55 mm and an outer diameter of 11.5 mm having a foamed rubber layer 2b on the outside was produced.

This was cut into a predetermined length, and a 6 mmφ metal shaft was inserted into the hose-shaped inner tube while inflating it by blowing air at a pressure of 1 kg from the opposite side to the shaft insertion side (FIG. 2). . The hardness of the conductive rubber roll obtained in this manner (FIG. 1) is 40 ⁰ (JI) in the inner layer.
S-A) outer layer was 40 ⁰ (Asker -C). The roll had a strong binding force between the shaft and the non-foamed rubber layer, and the shaft did not come off even when the rubber layer was turned while holding the shaft. In this case, if the thickness of the non-foamed rubber layer circumscribing the shaft is set to about 0.05 to 3 mm, the elasticity of the non-foamed rubber is higher than that of the foamed rubber, so that the binding force with the shaft is increased.

(Comparative Example) Using one extruder,
Using the die 3 as shown in FIG. 3 (a) connected thereto, only the ethylene-propylene-diene terpolymer rubber layer 2b containing the foaming agent was hollowed out under the same extrusion conditions.
And then vulcanized using the same conditions and equipment as in the example, and a hole having an inner diameter of 0.55 mm and an outer diameter of 11.5 mm was obtained.
A rubber-like vulcanizate was produced. This was cut into a predetermined length, and a 6 mmΦ metal shaft was inserted into the inner diameter while inflating the rubber layer by sending air at a pressure of 1 kg from the direction opposite to the shaft insertion side (FIG. 2). The conductive rubber roll thus produced has a hardness of 40 as measured by an Asker C hardness tester.
^Although it was ⁰ , this roller had a weak binding force between the shaft and the rubber layer, and the shaft was easy to come off when the rubber layer was turned while holding the shaft.

Example of the above rubber compounding EP35 100 EPDM PW380 70 made by Nippon Synthetic Rubber Process oil Carbon SRF 50 made by Idemitsu Kosan Ketjen EC 20 made of Asahi Carbon Conductive carbon Made by Lion Akzo Sulfur 2.5 Vulcanizing agent Tsurumi Chemical Accel TT 5 Vulcanization Accelerator Ouchi Shinko Chemical Zinc Hua 5 Vulcanization Aid Sakai Chemical Neocellon N1000 2.5 Blowing Agent Eiwa Chemical Co., Ltd. Calcium Oxide 2 Dehydrator Omi Chemical

[0020]

[Table 1]

[0021]

As described above, the basic effect of the present invention is as described in claim 1, wherein a conductive rubber rubber comprising a shaft and a conductive rubber layer provided on the outer periphery of the shaft is provided. In rubber, it is essential that the rubber layer is composed of at least two layers. Conventionally, when the rubber layer is a single layer, many required characteristics can be satisfied, in other words, a rubber layer of one material can be used. Although it was difficult to perform this, by making this a plurality of layers, it is possible to make each layer share the required characteristics, and to be able to satisfy more characteristics. (Sponge rubber layer) and a structure in which a non-foamed rubber layer is provided, it is possible to obtain a conductive rubber roll in which the shaft and the rubber layer can be firmly fixed without using an adhesive. Was.

Further, the effect of the present invention is that the above-mentioned rubber layers are extruded simultaneously and continuously in a hollow shape (tube shape) by a plurality of extruders and vulcanized.
It is possible to simplify the conventional manufacturing process and contribute to cost reduction by cutting into an appropriate size and inserting a shaft later to obtain a conductive rubber roll.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a conductive roll of the present invention.

FIG. 2 is a schematic partial cross-sectional view (inserting a shaft into a hollow (tube-shaped) rubber vulcanizate) showing an example of a method for producing a conductive roll of the present invention.

FIG. 3 (2) is a schematic cross-sectional view showing a die of a two-layer rubber extruder used for manufacturing the conductive roll of the present invention. FIG. 3A shows an ordinary one-layer rubber extruder.

[Explanation of symbols]

 1: shaft 2: rubber layer (base layer) 2a: non-foamed rubber layer (inner layer) 2b: foamed rubber layer (outer layer) 3: extrusion die

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/02

Claims (3)

(57) [Claims] 1. A conductive rubber roller comprising a shaft and a conductive rubber layer provided at least on the outer periphery of the shaft, wherein the rubber layer comprises at least two layers. A conductive rubber roller, wherein the inner layer (shaft side) is a non-foamed rubber layer and the outer layer (use surface side) is a foamed rubber layer. 2. The conductive rubber roller according to claim 1, wherein the inner diameter of the hollow portion of the rubber layer is sufficiently smaller than the outer diameter of the shaft to be inserted.
La. 3. A conductive rubber roller comprising a shaft and a conductive rubber layer provided on the outer periphery of the shaft.
The rubber layer is a conductive rubber roller comprising at least two layers, wherein the two layers are simultaneously and integrally extruded by a plurality of extruders into a hollow shape (tube shape), 3. The method for producing a conductive rubber roller according to claim 1, wherein a shaft is inserted after vulcanization.