# US 8,465,682 B2 · Semiconductive rubber belt, and process for producing the same

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- Number: US 8,465,682 B2
- Document ID: US8465682B2
- Status: Granted
- Kind: B2
- Application number: 13/614,950
- Filed: 2012-09-13
- Published: 2013-01-10
- Granted: 2013-06-18
- Earliest claimed: 2009-03-12
- Assignees: Toyo Tire & Rubber Co., Ltd.
- Applicants: Takahiro Nakagawa
- Inventors: Takahiro Nakagawa
- Web page: https://patentgrep.com/patent/US8465682B2

## CPC

- B29C 48/157: Coating linked inserts, e.g. chains
- B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C 48/151: Coating hollow articles
- B29K 2021/00: Use of unspecified rubbers as moulding material
- Y10T 428/1386: Natural or synthetic rubber or rubber-like compound containing
- Y10T 428/24942: including components having same physical characteristic in differing degree
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An object of the present invention is to provide a semiconductive rubber belt wherein a variation in the electric resistance is decreased, in particular, in the belt circumferential direction so that high-quality images can be formed, and a process for producing the same. In order to achieve the object, in a case where on any single straight line extended in the belt circumferential direction, the maximum value of the molecular orientation ratio correction value MOR-C of the semiconductive rubber belt, the minimum value thereof, and the average thereof are set to satisfy a specified relationship.

## Claims

### Claim 1

A process for producing a seamless semiconductive rubber belt having a volume resistivity of 104 to 1012 Ωcm, comprising:
an extruding step of using an extruder equipped with a crosshead having an inner cylinder section wherein a spiral flow type groove is made to plasticize an unvulcanized rubber composition having a scorch time t5 of 10 to 18 minutes, and extruding the composition through the extruder,
an unvulcanized rubber belt molding step of shifting, inside the inner cylinder section, a cylindrical mold in a direction substantially orthogonal to the extrusion direction of the unvulcanized rubber composition in the extruder while making the unvulcanized rubber composition into a layer form and allowing the layer-form unvulcanized rubber composition to cover the outside surface of the cylindrical mold, thereby yielding an unvulcanized rubber belt, molded body, and
a vulcanizing step of vulcanizing the unvulcanized rubber belt molded body, thereby yielding the semiconductive rubber belt.

### Claim 2 (depends on 1)

The process for producing the semiconductive rubber belt according to claim 1, wherein the ratio between the maximum outside diameter d of the inner cylinder section and the outside diameter e of a discharging opening in the section (the die contraction ratio) satisfies the following: 0.2≦e/d≦0.8, and further the shift speed of the cylindrical mold is 1 m/minute or less in the unvulcanized rubber belt molding step.