WO2009133871A1

WO2009133871A1 - Conductive endless belt

Info

Publication number: WO2009133871A1
Application number: PCT/JP2009/058318
Authority: WO
Inventors: 安藤　幸夫
Original assignee: 株式会社ブリヂストン
Priority date: 2008-05-01
Filing date: 2009-04-28
Publication date: 2009-11-05
Also published as: JP2009271158A; CN102016728A

Abstract

Disclosed is a conductive endless belt (3), on at least one face of which is provided a guide rib (32) protruding in the circumferential direction, with which it is possible to form a guide rib of superior flexibility and low impact resilience, that has excellent wear resistance and a low friction coefficient, and whereby excellent running stability and quietness can be achieved by using millable urethane rubber to form the aforementioned guide rib (32).

Description

Conductive endless belt

The present invention relates to a conductive endless belt suitably used as an intermediate transfer belt in an electrophotographic color printer or the like, and more specifically, a conductive endless belt in which a guide rib for preventing meandering is provided on the inner peripheral surface of the belt. About.

Conventionally, an intermediate transfer belt method is known as a color printing method using toner.

As shown in FIG. 2, the image forming apparatus that performs color printing by the intermediate transfer belt system includes four developing devices 1a to 1d that perform development in four colors of black B, yellow Y, magenta M, and cyan C, respectively. A toner image is formed in each color on each photosensitive drum 2a to 2d, and a voltage is applied from the transfer roller 5 to the intermediate transfer belt 3 stretched in contact with each photosensitive drum 2a to 2d. A toner image of each color (black B, yellow Y, magenta M, cyan C) formed on 2 to 2d is transferred to the surface of the intermediate transfer belt 3 to form a color image on the surface of the intermediate transfer belt 3, and the secondary image A voltage is applied to the recording paper (recording medium) 4 in contact with the intermediate transfer belt 3 by the transfer roller 7 to transfer the color image on the surface of the intermediate transfer belt 3, and this is heated and fixed by the fixing device 6. Going on.

In the intermediate transfer belt 3 used in such an image forming apparatus, a guide rib 32 is often formed along the side edge of the inner peripheral surface of the belt body 31 as shown in FIG. The belt 32 is engaged with a guide groove provided on a pulley or a driving roller to prevent the belt from meandering (Patent Document 1: Japanese Patent Laid-Open No. 11-352832).

The guide rib 32 has been implemented or proposed to be formed of a solid material obtained from synthetic rubber, liquid polyurethane, or the like, or a low resilience material such as millable silicone or urethane foam.

However, solid materials obtained from synthetic rubber, liquid polyurethane, etc. have high resilience and a high coefficient of friction in dry environments. Derailment due to may occur. Further, in the case of a low resilience material such as millable silicone or foamed urethane, the tear strength is inferior and the wear resistance is not always sufficient. In particular, image quality may be deteriorated due to generation of abrasion powder. Furthermore, in the case of a urethane material, carcinogenicity is pointed out to the amine contained in the curing agent used, and it is desirable to avoid use for reducing the environmental load.

The guide ribs of conductive endless belts such as the above intermediate transfer belts are: ・ Flexibility (prevention of wrinkles and prevention of bending fatigue) ・ Abrasion resistance (prevention of abrasion powder) ・ Low coefficient of friction (prevention of lifting and chattering by stick-slip) However, as described above, the materials that make up the conventional guide ribs do not fully satisfy these performances, and the development of guide ribs that satisfy these required performances has not been achieved. desired.

Japanese Patent Laid-Open No. 11-352832

The present invention has been made in view of the above circumstances, and has low impact resilience and excellent flexibility, and has a guide rib having good wear resistance and a low coefficient of friction, and has good running stability and running quietness. An object is to provide a conductive endless belt that can be achieved.

As a result of intensive studies to achieve the above object, the inventor has produced a conductive endless belt such as an intermediate transfer belt by projecting a guide rib along the circumferential direction on one surface side of an endless belt. By forming the above guide ribs using millable urethane rubber, it is possible to form guide ribs with low resilience, excellent flexibility, and excellent wear resistance, and by reducing the friction coefficient, stick slip It is also possible to prevent chatter noises caused by squeezing, and since no amine-based curing agent is required as in the case of using liquid polyurethane, environmental impact can be reduced and good running stability can be achieved. The present invention has been completed by finding that a conductive endless belt having high performance, durability and running quietness can be obtained.

Accordingly, the present invention provides a conductive endless belt in which a guide rib extending in the circumferential direction is provided on at least one surface side of an endless belt, and the guide rib is formed using millable urethane rubber. Is to provide.

The conductive endless belt of the present invention uses millable urethane rubber to form guide ribs with excellent flexibility, wear resistance, and low friction coefficient. Therefore, it has good running stability, durability and running quietness.

It is a schematic sectional drawing which shows an example of the electroconductive endless belt concerning this invention. It is the schematic which shows the color printing electrophotographic apparatus by an intermediate transfer belt system.

Hereinafter, the present invention will be described in more detail.
In the present invention, as shown in FIG. 1, the guide rib 32 of a conductive endless belt in which a guide rib 32 protrudes along the circumferential direction on one surface side (usually the inner peripheral surface) of an endless belt-shaped belt body 31 is millable. It is formed using urethane rubber.

Here, millable urethane is a kneading type urethane that can be kneaded with a roll against liquid urethane (casting type) or thermoplastic urethane (injection type). Any of these may be used, but a polyester system is preferably used for applications where wear resistance is important, and a polyether system is preferably used for applications where flexibility is important. . The vulcanization system may be any of sulfur, peroxide, and isocyanate, but a peroxide vulcanization system is preferably used from the viewpoint of changes in urethane hardness over time and hardness variations.

Such a millable urethane rubber can be a commercially available product, such as Bayer “Miracene Series”, “Urepan Series”, NOK “Iron Rubber Series”, and the like.

To the urethane rubber forming the guide rib 32, an inorganic reinforcing material such as calcium carbonate, dexterous clay, silica, mica and an organic reinforcing material such as fine particle silicone powder can be added. The impact resilience can be reduced or adjusted. In this case, although not particularly limited, the rebound resilience can be reduced or adjusted more favorably by using carbon black and these reinforcing materials in combination. The amount of the reinforcing material added is appropriately set according to the type of the millable urethane rubber and the type of the reinforcing material to be added. Usually, the amount is 5 to 30 parts by mass, particularly 100 parts by mass of the millable urethane rubber. The amount is preferably 10 to 20 parts by mass. Similarly, the blending amount of carbon black is not particularly limited, but is usually 10 to 20 parts by mass, and preferably 10 to 15 parts by mass.

In addition, modifiers such as AC polyethylene, spherical silicone powder (for example, “Tospearl” manufactured by Nissho Sangyo Co., Ltd.), magnesium hydrogen carbonate, sodium hydrogen carbonate are added to reduce and adjust the friction coefficient. In particular, it is preferable to reduce and adjust the coefficient of friction by using the above AC polyethylene and spherical silicone powder in combination. In this case, the amount of AC polyethylene or spherical silicone powder added is appropriately set according to the type of millable urethane rubber and is not particularly limited, but normally, AC polyethylene is 5 per 100 parts by mass of millable urethane rubber. The spherical silicone powder is preferably 2 to 10 parts by mass, particularly preferably 5 to 10 parts by mass.

Furthermore, various modifiers such as triallyl isocyanurate (TAIC), plastorodin, zinc stearate, metal soap, octylbenzyl phthalate (OBP), benzoic acid ester (for example, “Benzoflex” manufactured by VELSICOL, USA), DIC, etc. Appropriate amounts of known additives such as plasticizers such as “W # 620” manufactured by the company and “DINA D-640A” manufactured by J-plus and other polycarbodiimides (hydrolysis inhibitors) can be added.

Since the guide rib 32 of the conductive endless belt of the present invention is formed using the above millable urethane rubber, the coefficient of friction can be reduced while achieving low rebound resilience. In other words, when using conventional materials such as liquid urethane, if you try to reduce the friction coefficient in order to prevent the generation of abrasion powder due to wear, the rubber becomes harder and the resilience becomes higher, causing rise and chatter noise. However, it is difficult to satisfy both performances at the same time. However, in the present invention, this contradictory problem can be solved at the same time.

In this case, in the present invention, the hardness of the rubber composition forming the guide rib is preferably 50 to 80, particularly 60 to 70 as the durometer A hardness defined in JIS K6253. If the hardness is less than 50, the ribs are deformed easily when the belt is running, and the belt is likely to meander. It becomes sufficient, the turning radius becomes large, and it is easy to get on the pulley, and the chatter noise easily occurs due to the frictional force with the pulley.

As described above, the guide rib 32 of the present invention can achieve a low coefficient of friction, but the specific coefficient of friction is not particularly limited. It is preferably 1.4 or less (pressure contact load 400 g, sliding speed 50 mm / sec), particularly 1.3 or less, more preferably 1 or less, with respect to polyacetal resin widely used as a material for traveling pulleys. It is possible to effectively prevent the belt from running up and the generation of wear powder. In the present invention, the use of millable urethane rubber makes it possible to easily achieve the coefficient of friction while maintaining low rebound resilience, and more specifically, blending or blending of the above AC polyethylene or spherical silicone powder. The above frictional resistance can be achieved by adjusting the amount, and further by shot blasting, embossing, buffing / polishing, etc. applied to the guide rib surface after formation. The lower limit value of the friction coefficient is not particularly limited, but it is usually in the range where a stable friction coefficient can be obtained up to about 0.5 to 1, particularly up to about 0.7.

Furthermore, as described above, the guide rib 32 of the present invention can achieve low rebound resilience while achieving the low friction coefficient, specifically, the rebound measured according to JIS K6400-3 (2004). It is preferable to prepare such that the elastic modulus is 25 to 50%, particularly 35 to 40%. And in this invention, such low friction coefficient can be easily achieved with the said low rebound resilience by using millable urethane rubber, More specifically, the said inorganic type reinforcing material and organic type reinforcing material The low coefficient of friction can be achieved by adjusting the blending amount and adjusting the blending amount.

This guide rib 32 is kneaded by adding and compounding the above compounding agent and a vulcanizing agent such as sulfur, peroxide, isocyanate, etc. according to the kind of the millable urethane rubber, and press molding, extrusion molding, roll molding. It can be obtained by molding into a desired guide rib shape by injection molding or the like and heating at a predetermined temperature. In addition, although the cross-sectional trapezoidal guide rib 32 is shown in FIG. 1, the cross-sectional shape may be a shape other than the trapezoid such as a square shape or a triangular shape.

Further, the guide rib 32 after formation can be subjected to known post-processing such as the above-described shot blasting, embossing, buffing / polishing, etc. on the surface thereof, and the above-mentioned friction coefficient can be achieved by these post-processing. You can also.

As a method of bonding the guide rib 32 to the belt main body 31, a known method can be adopted depending on the material of the belt main body 31. For example, a method using a double-sided adhesive tape, a one-component or two-component resin containing Alternatively, a method using a rubber adhesive, a hot melt bonding method, or the like can be appropriately employed. The material and structure of the belt main body 31 are not limited, and a belt having a known material and structure can be used as the belt main body 31 according to the use of the belt.

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.

[Examples 1 to 9]
Each compounding agent shown in Table 1 was mixed and kneaded at 60 ° C. for 15 minutes using a kneader kneading machine to prepare a rubber composition, which was roll-formed and heated to 150 ° C. to be cured. A guide rib member having a rectangular parallelepiped shape with a thickness of 5 mm and a thickness of 1.5 mm was produced.

For the obtained guide rib member, the friction coefficient, chatter noise generation, wear resistance, hardness, compression set, and impact resilience were evaluated by the following methods. The results are shown in Table 1.

[Comparative Example 1]
7.4 parts by mass of aromatic amine (4,4′methylene-bisdichloroaniline) as a curing agent is added to 100 parts by mass of liquid urethane (“Coronate 4076” manufactured by Nippon Polyurethane Co., Ltd.), heated to 60 ° C. A time-cured sheet-like sample having a length of 700 mm and a width of 300 mm was produced, and a guide rib member having the same dimensions as in Examples 1 to 9 was cut out from this sample. The friction coefficient, chatter noise generation, wear resistance, hardness, compression set, and impact resilience were evaluated in the same manner as in Examples 1-9. The results are shown in Table 2.

[Comparative Example 2]
Natural rubber (RSS # 1) 100 parts by mass, SRF carbon 15 parts by mass, zinc white 5 parts by mass, stearic acid 1 part by mass, dioctyl phthalate (DOP) 10 parts by mass, vulcanization accelerator: tetramethylthiuram monosulfide (TMTM ) 1.5 parts by mass, vulcanization accelerator: 2 parts by mass of N-cyclohexyl-2-benzothiazolylsulfenamide (CZ), 10 parts by mass of calcium carbonate, 0.5 parts by mass of sulfur are mixed at 160 ° C. A guide rib member having the same dimensions as in Examples 1 to 9 was produced by press vulcanization for 20 minutes. The friction coefficient, chatter noise generation, wear resistance, hardness, compression set, and impact resilience were evaluated in the same manner as in Examples 1-9. The results are shown in Table 2.

[Comparative Example 3]
100 parts by weight of acrylic rubber (“AREX411” manufactured by JSR), 15 parts by weight of SRF carbon, 1 part by weight of stearic acid, 2 parts by weight of anti-aging agent (Nocklac CD), 2.5 parts by weight of sodium stearate, 10 parts of calcium carbonate Part by mass, 0.3 part by mass of sulfur (“Sulfax PMC” manufactured by Tsurumi Chemical Co., Ltd.) are mixed, kneaded with a 10 L kneader, and 160 ° C. for 15 minutes using a 600 mm × 300 mm × 15 mm mold. The guide rib member having the same dimensions as those of Examples 1 to 9 was produced by vulcanization molding under the conditions described above. The friction coefficient, chatter noise generation, wear resistance, hardness, compression set, and impact resilience were evaluated in the same manner as in Examples 1-9. The results are shown in Table 2.

[Comparative Example 4]
100 parts by weight of millable silicone rubber (“KE575U” high strength methyl vinyl silicone rubber compounded by Shin-Etsu Chemical Co., Ltd.), 15 parts by mass of SRF carbon and cross-linking agent (“CBA” 2,5-dimethyl-2 by Shin-Etsu Chemical Co., Ltd.) , 5-bis (t-butylperoxy) hexane containing 80%) is first vulcanized at 170 ° C. for 20 minutes and further subjected to secondary vulcanization at 200 ° C. for 4 hours. As a result, guide rib members having the same dimensions as in Examples 1 to 9 were produced. The friction coefficient, chatter noise generation, wear resistance, hardness, compression set, and impact resilience were evaluated in the same manner as in Examples 1-9. The results are shown in Table 2.

[Evaluation test method]
(Coefficient of friction)
A roller of polyacetal resin ("TENAC" manufactured by Asahi Kasei Co., Ltd.) is pressed against the guide rib member at a load of 200g and 400g and rotated at a peripheral speed of 50mm / sec. The ratio of the measured load to the applied load was taken as the friction coefficient.

(Generation of chatter noise)
In the same manner as in the above (coefficient of friction) measurement, the roller and the guide rib member are slid, and the frictional sound at the time of measuring the coefficient of friction is subjected to frequency analysis using a fast Fourier analyzer (FFT). , × was evaluated in four stages.

(Abrasion resistance)
The amount of wear at 1500 wear revolutions was evaluated by a taper wear tester (grinding stone HC20) according to the following criteria. ○: 1% or less, △: 1 to 2%, ×: 2% or more

(Rubber hardness)
Measurement was performed using a durometer A (spring type) in accordance with JIS K6253.

(Compression set)
In accordance with JIS K6262, the measurement was carried out under the conditions of 70 ° C., 22 hours, and the amount of compressive deformation of 25%, and evaluated according to the evaluation criteria of ○: 3% or less, Δ: 3-5%, ×: 5% or more.

(Rebound resilience)
In accordance with the provisions of JIS K6400-3, the steel balls were dropped 10 times each, and the average of the measured values was defined as the resilience modulus. The measurement was performed at 22 ° C. and 50%.

* 1 Mirable Urethane: Bayer "Miracene HT"
* 2 TAIC / OBP: triallyl isocyanurate / octyl benzyl phthalate * 3 Tospearl 2000: spherical silicone powder manufactured by Nissho Sangyo Co., Ltd. * 4 Stavazol P: hydrolysis inhibitor manufactured by Yoko Hiraizumi * 5 Perhexa 3M-40: Peroxide vulcanizing agent manufactured by Sanshin Chemical Industry Co., Ltd.

From the results in Tables 1 and 2, it was confirmed that the rubber composition forming the guide ribs of the conductive endless belt of the present invention has good performance.

1a to 1d Developing devices 2a to 2d Photosensitive drum 3 Intermediate transfer belt (conductive endless belt)
31 Belt body 32 Guide rib 4 Recording paper (recording medium)
5 Transfer roller 6 Fixing device 7 Transfer roller

Claims

A conductive endless belt, in which a guide rib extending in the circumferential direction is provided on at least one surface side of the endless belt, and the guide rib is formed using millable urethane rubber.
The conductive endless belt according to claim 1, wherein the guide rib has a durometer A hardness of 50 to 80 as defined in JIS K6253.
3. The conductive endless belt according to claim 1 or 2, wherein the guide rib has a friction coefficient of 1.4 or less as measured by pressing against a polyacetal resin with a load of 400 g and sliding at 50 mm / sec.
The conductive endless belt according to claim 3, wherein the surface of the guide rib is subjected to shot blasting, embossing or polishing.
The conductive endless belt according to any one of claims 1 to 4, wherein the guide rib is formed of a millable urethane rubber composition to which an inorganic reinforcing material and / or an organic reinforcing material is added.
6. The conductivity according to claim 5, wherein the inorganic reinforcing material is one or more selected from calcium carbonate, dexterous clay, magnesium silicate, silica-based filler, and mica, and the organic reinforcing material is a silicone powder. Endless belt.
The conductive endless belt according to any one of claims 1 to 6, wherein the guide rib is formed of a millable urethane rubber composition to which AC polyethylene and spherical silicone powder are added.