JP2002295450A - Material for fixing roller covering tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for a fixing roller covering tube using a tetrafluoroethylene-perfluoro (alkylvinylether) copolymer and excellent in crack ing resistance by reducing hardness of the tube, following improvement of pic ture quality as a fixing roller and having proper molar weight. SOLUTION: This material for the fixing roller covering tube is constituted of the copolymer having a copolymer composition of tetrafluoro-ethylene of 90-99 mol% and perfluoro (ethylvinylether) of 10-1 mol% and specific melt viscosity of 5×10<3> -50×10<3> kg/m.s (372 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a material for a tube covered with a fixing roller. More specifically, the present invention relates to a tube material for covering a fixing roller used for fixing a toner in a copying machine, a printer for a personal computer, and the like.

[0002]

2. Description of the Related Art As a tube material for covering the surface of a fixing roller, a tetrafluoroethylene-perfluoro (propyl vinyl ether) copolymer has conventionally been widely used. However, although this copolymer has good paper releasability and durability, it has high hardness, so that it has low followability to toner particles as a fixing roller-covered tube, and high performance of a copy image is achieved. At present, there is a problem that high image quality is not sufficient.

For this reason, it is effective to reduce the hardness of the tube covered with the fixing roller, but in order to reduce the hardness, it is possible to take a measure of increasing the copolymerization amount of perfluoro (alkyl vinyl ether). However, since perfluoro (propyl vinyl ether) has poor copolymerizability, it is difficult to decrease the hardness by increasing the copolymerization rate. Further, when a large amount of perfluoro (propyl vinyl ether) is used to increase the copolymerization rate, the molecular weight of the obtained copolymer becomes low, and a copolymer having desired mechanical strength cannot be formed. Furthermore, even if the copolymerization amount of perfluoro (propyl vinyl ether) is increased and the hardness is reduced, if the molecular weight is low, cracks occur in the tube covering the rotating member during use, and rotation occurs. The function as a member is lost.

On the other hand, some fluorovinyl ethers having a polyfluoroalkyl group —CH ₂ (CF ₂ ) nX (X: hydrogen atom or halogen atom) having a hydrogen atom in the side chain have a good copolymerization ratio, Japanese Patent Publication No. Hei 7-2816), hydrogen in the molecule undergoes chain transfer during the polymerization reaction during the polymerization reaction, and the desired molecular weight is reduced, so that a desired copolymer cannot be obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing roller-covered tube material using a tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer. An object of the present invention is to provide a tube material for coating a fixing roller having excellent crack resistance by following a high image quality as a roller and having an appropriate molecular weight.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Copolymer composition of tetrafluoroethylene 90-99 mol% and perfluoro (ethyl vinyl ether) 10-1 mol% and 5
This is achieved by a material for a fixing roller-coated tube made of a copolymer having a specific melt viscosity (372 ° C.) of × 10 ³ to 50 × 10 ³ kg / m · s.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Perfluoro (ethyl vinyl ether) copolymerized with tetrafluoroethylene has a copolymer content of 10 to 1 mol%, preferably 8 to 5 mol% in the copolymer. Used. At a copolymerization ratio below this, it has a high hardness like the polytetrafluoroethylene or tetrafluoroethylene-perfluoro (propyl vinyl ether) copolymer, while if it is copolymerized at a higher ratio, it becomes softer than necessary. And the paper separation property and the crack resistance are reduced.

Further, this copolymer has a size of 5 × 10^Three~ 50 × 10^Threek
g / m ・ s, preferably 7 × 10^Three~ 30 × 10 ^ThreeSpecific melting viscosity of kg / m
What has a temperature (372 degreeC) is used. Specific solution below this
Cracks occur in the tube when melt viscosity is used.
May be used.
In this case, the moldability is poor and a tube with a uniform wall thickness cannot be obtained.
Sometimes.

The formation of a tubular film using a tetrafluoroethylene-perfluoro (ethyl vinyl ether) copolymer having such properties is performed by a melt extrusion method using a circular tube die. The tube is generally about 5 to 500 μm, preferably about 50 to 100 μm thick, about 0.1 to less than the outer diameter of the fuser roller on which it is coated.
It is formed so as to have a large outer diameter of about 1.5 mm.

A tube having such dimensions is coated by heat-sealing via a primer onto a surface rubber layer such as an aluminum cylindrical metal core having silicone rubber coated on the surface constituting the fixing roller. .

[0011]

The fixing roller in which the tube formed from the fixing roller-covered tube material according to the present invention is formed as a surface layer not only improves the image definition but also uses a conventional soft fluororesin. This has the effect of significantly improving the crack resistance, which has been a problem in the case where it is present.

[0012]

Next, the present invention will be described with reference to examples.

EXAMPLE Copolymer composition of 92 mol% of tetrafluoroethylene and 8 mol% of perfluoro (ethyl vinyl ether) and 20 × 10 ³ kg
/ m · s from a copolymer having a specific melt viscosity of (372 ° C), melt extrusion using a circular tube die, outer diameter 40 mm, thickness 50
A μm tube was molded. This tube is coated on a silicone rubber layer of an aluminum cylindrical core metal (outside diameter 39.0 mm) coated with silicone rubber by heat sealing via a primer, and a fixing roller for a copier printer. Was prepared.

The following items were measured for this fixing roller. Image sharpness: Performed a full-color print test, and examined the first print color and the 500th print color and bleed, evaluated very good as ◎, good as 〇, and slightly poor as や. Crack resistance: Fixation Copies were made at a speed of 20 sheets per minute at a temperature of 200 ° C, and after the copying of 100,000 sheets, the presence or absence of cracks in the copolymer layer was observed. ◎, good ones were evaluated as poor, and slightly poor ones were evaluated as paper. Paper releasability: Under the above cracking test conditions, the paper releasability between the fixing roller and the copy paper was examined. , Rated slightly inferior

COMPARATIVE EXAMPLE 1 In the examples, the same copolymer composition was used, and the specific melt viscosity (3
(72 ° C.) a tetrafluoroethylene-perfluoro (ethyl vinyl ether) copolymer having a concentration of 3 × 10 ³ kg / m · s was used.

Comparative Example 2 In the examples, a tetrafluoroethylene-perfluoro (propyl vinyl ether) copolymer (AP-230 manufactured by Daikin) was used in place of the tetrafluoroethylene-perfluoro (ethyl vinyl ether) copolymer. Was.

The evaluation results in the above Examples and Comparative Examples are shown in the following table together with the hardness of the copolymer layer (using ASTM-D-2240 durometer). Table Example Image clarity Crack resistance Paper release hardness Example ◎ ◎ 〇 D58 Comparative Example 1 ◎ △ 〇 D58 〃 2 △ ◎ 〇 D60

The value of the specific melt viscosity was determined by using a melt indexer manufactured by Toyo Seiki Co., Ltd., placing the copolymer in a cylinder having an inner diameter of 9.5 mm, maintaining the temperature at 372 ° C. for 5 minutes, and applying a piston load of 5 kgf. It was extruded through an orifice having an inner diameter of 2.095 mm and a length of 8.00 mm, and was obtained by dividing the extrusion speed (g / min) at this time by 53150.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 214: 18) C08L 27:18 C08L 27:18 (72) Inventor Takashi Enoda Isoharamachikami, Kitaibaraki City, Ibaraki Prefecture 831-2 Aida, Chemitech Division, Nippon Mektron Co., Ltd. (72) Inventor Seiichi Nakamura 831-2, Kami-Aida, Isohara-machi, Kitaibaraki-shi, Ibaraki AA13 AA21 AA51 EA05 FA12 FA14 GA02 GA57 GA58 GA66 HA04 HA12 4F071 AA26 AA26X AA27 AA75 AA88 AA88X AF13 AF25 AF53 AG21 AG27 AH16 BA01 BC05 BC12 4J100 AC26P AE39Q CA04 DA09 DA48 EA05 JA28

Claims (3)

[Claims] 1. A copolymer composition of 90 to 99 mol% of tetrafluoroethylene and 10 to 1 mol% of perfluoro (ethyl vinyl ether) and a specific melt viscosity of 5 × 10 ³ to 50 × 10 ³ kg / m · s ( Three
(72 ° C.). 2. A fixing roller covered tube formed from the material for a fixing roller covered tube according to claim 1. 3. A fixing roller having the fixing roller covered tube according to claim 2 formed on a surface layer.