JP2000304101A - Fluorine resin-covered belt and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine resin-covered belt excellent in a durability formed with a fluorine resin film on a belt base body consisting of a rubber or resin, without thermal deterioration on the interface between the belt base body and fluorine resin film integrally compounded, and the manufacturing method thereof. SOLUTION: In this belt, a fluorine resin film 2 is formed on the belt base body 1 consisting of a rubber or resin. Thermal decomposition starting temperature (Trp) of the rubber or resin is below the melting point (Tf) of the fluorine resin and the belt base body and fluorine resin film are integrally compounded. The strength of the fluorine resin film is 100 kgf/cm2 or more and its elongation is 150% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluororesin-coated belt in which a fluororesin film is formed on a belt base made of rubber or resin, and a method for producing the same. The fluororesin-coated belt of the present invention can be applied to a wide variety of uses such as conveyance, and in particular, various belts (for example, recording paper and toner conveyance belts) in image forming apparatuses such as electrophotographic copying machines and printers. , Transfer belt, etc.).

[0002]

2. Description of the Related Art Conventionally, belts formed of various rubbers and resins have been used for a wide range of uses such as conveying. In such a belt, when it is applied to applications that require a high degree of surface release, smoothness, heat resistance, etc., a fluororesin coating is integrally compounded on a belt base made of rubber or resin. Therefore, it is effective to form a fluororesin-coated belt.

For example, in an image forming apparatus such as an electrophotographic copying machine or a printer, a transfer belt, a charging belt,
Various belt members are used as a fixing belt, a conveyance belt, and the like. These belt members are required to have excellent toner releasability. Also,
Depending on the use of the belt member, it is also required to have excellent surface smoothness and heat resistance, in addition to the releasability.
More specifically, a transfer belt will be described as an example.

In an electrophotographic image forming process, generally, a charging step for uniformly and uniformly charging a photoreceptor surface, an exposure step for performing image exposure to form an electrostatic latent image on the photoreceptor surface, A developing step of forming a toner image by attaching a toner having a reverse charge to the latent image, a transferring step of transferring the toner image onto a transfer material such as recording paper, and heating the transferred toner image. An image is formed by sequentially passing through a fixing step of fixing on a transfer material.

The transfer belt transfers a toner image formed on a photosensitive member in accordance with an electrostatic latent image in a developing process once onto the transfer belt, and then transfers the transferred toner image onto a transfer material such as recording paper. It plays the role of transferring. Conventional transfer belts are formed of urethane rubber or the like. However, since the surface of the urethane rubber is inferior in releasability, toner easily adheres to the transfer belt made of urethane rubber, and the surface of the transfer belt is easily stained. When the surface of the transfer belt is stained with toner, the stain is transferred to recording paper, and an offset phenomenon occurs in which an image is doubled. Even in a method in which the recording paper is directly charged by the transfer belt to transfer the toner image on the photosensitive member onto the recording paper, if the toner adheres to the surface of the transfer belt and becomes dirty, the dirt adheres to the recording paper.

In order to prevent the transfer belt from being stained and the offset phenomenon caused by the transfer belt, it is effective to provide a fluororesin coating on the surface of the transfer belt to enhance the releasability of the toner. However, it has been extremely difficult to form a fluororesin coating on a belt base made of rubber or resin such as urethane rubber without deteriorating the belt base. The reason is that in the step of forming a fluororesin film, it is necessary to apply a fluororesin paint on the belt substrate, dry it, and then bake it at a temperature equal to or higher than the melting point of the fluororesin to form a film. Because the melting point is high, rubber and resin constituting the lower belt base are deteriorated in the firing step.

For example, a belt base made of urethane rubber is thermally degraded at the sintering temperature of a fluororesin, deforms, cracks, and breaks, and the shape of the belt cannot be maintained. When the decomposition start temperature of the rubber or resin constituting the belt base is lower than the melting point of the fluororesin, the belt base is deteriorated in the firing step of the fluororesin, and the strength is significantly reduced. A belt base made of a resin having a decomposition start temperature equal to or higher than the melting point of a fluororesin is often inferior in elasticity, flexibility, or flexibility, and is not necessarily suitable for uses such as a transfer belt. On the other hand, if the firing conditions of the fluororesin are relaxed in order to prevent the rubber and resin constituting the belt base from deteriorating, the fluororesin is not sufficiently fired, so that only a fluororesin coating with low strength and low elongation can be obtained. As a result, the durability of the fluororesin-coated belt is significantly reduced.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluororesin-coated belt in which a fluororesin coating is formed on a belt substrate made of rubber or resin such as urethane rubber. An object of the present invention is to provide a fluororesin-coated belt excellent in durability, in which there is no thermal deterioration at the interface of the two, and the both are integrally compounded. Another object of the present invention is to provide a fluororesin-coated belt which is suitable as a transfer belt in which surface contamination due to toner sticking is prevented and a double image does not appear. Further, an object of the present invention is to provide a method of manufacturing a fluororesin-coated belt capable of forming a fluororesin film having excellent mechanical properties on a belt substrate without deteriorating a rubber or a resin constituting the belt substrate. Is to do.

The present inventors have conducted intensive studies to overcome the problems of the prior art, and as a result, instead of the conventional method of forming a fluororesin coating on a belt base, a fluororesin was formed on the inner surface of a cylindrical mold. The present inventors have conceived a method of forming a film and forming a belt base on the fluororesin film using a rubber or a resin material. According to this method, first, a fluororesin film that requires a firing step at a high temperature is formed, and then a rubber or resin layer can be formed. However, it is possible to obtain an integrally composite fluororesin-coated belt without thermal degradation at the interface. According to this method, the fluorocarbon resin can be sufficiently fired without thermally deteriorating the belt base, so that a fluorocarbon resin film having excellent strength and elongation can be formed. If a fluororesin film is formed by a powder coating method using a fluororesin powder as a fluororesin,
Mechanical properties such as strength and elongation of the fluororesin coating are remarkably excellent, and a fluororesin-coated belt excellent in durability can be obtained. The present invention has been completed based on these findings.

[0010]

According to the present invention, in a fluororesin-coated belt in which a fluororesin coating is formed on a belt base made of rubber or resin, the thermal decomposition onset temperature (Trp) of the rubber or resin is reduced. Melting point of resin (T
f), wherein the belt base and the fluororesin coating are integrally compounded, and a fluororesin-coated belt is provided.

Further, according to the present invention, in a method for manufacturing a fluororesin-coated belt in which a fluororesin coating is formed on a belt base made of rubber or resin, (1) the fluororesin coating is formed on the inner surface of a cylindrical mold. And (2) inserting the core with its axis aligned with the bore of the cylindrical mold,
(3) A rubber or resin material is injected into a gap between the fluororesin coating on the inner surface of the cylindrical mold and the core, and is cured or solidified to form a rubber or resin layer. The present invention provides a method for producing a fluororesin-coated belt, which comprises integrally forming a fluororesin coating on a belt base.

[0012]

DETAILED DESCRIPTION OF THE INVENTION A cylindrical mold used in the present invention is:
It is preferably made of a metal such as iron, stainless steel, or aluminum, but is not limited thereto as long as it has heat resistance to withstand the firing temperature of the fluororesin.
Further, the cylindrical mold may be a mold having a cylindrical hollow used as a mold, and the whole including the outer shape does not necessarily have to be a cylindrical shape. Or a flange or the like may be present. The provision of good releasability on the inner surface of the cylindrical mold facilitates the operation (demolding) of pulling out the belt base integrally formed with the fluororesin coating from the cylindrical mold in the final step. It is preferable in doing. In order to give the inner surface of the cylindrical mold a releasability, there is a method of performing a smoothing process. In order to smooth the inner surface of the cylindrical mold, for example, there is a method of using a drawn material in the case of aluminum, and a plating process such as chrome plating and nickel plating in the case of other materials. There is a way to do it. In the case of a cylindrical mold made of another material, a method of polishing the inner surface by a honing process and further performing a plating process such as chrome plating and nickel plating may be adopted. It is preferable that the surface roughness of the inner surface of the cylindrical mold be reduced as much as possible by such a smoothing treatment. By smoothing the inner surface of the cylindrical mold, it is possible to form a fluororesin layer having excellent surface smoothness in addition to facilitating demolding.
The surface roughness (Ra) of the inner surface of the cylindrical mold is preferably 1 μm or less, and particularly preferably 0.3 μm or less when a high degree of surface smoothness is required.

The inner diameter and length of the cylindrical mold can be determined according to the outer diameter and length of a desired belt member such as a transfer belt. The inner diameter of the cylindrical mold is substantially defined by the sum of the thickness of the belt base and the thickness of the fluororesin coating. The thickness of the cylindrical mold is not particularly limited, and can be determined in consideration of, for example, thermal conductivity and mechanical strength at the time of rubber curing, but is usually about 1 to 10 mm.

Examples of the fluororesin used in the present invention include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). ), Ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene / chlorotrifluoroethylene copolymer (ECTF)
E), polyvinylidene fluoride (PVDF) and the like. Among these, P is preferred because it is easy to obtain a fluororesin coating which is excellent in non-adhesiveness and hardly adheres the toner.
TFE, PFA and FEP are preferred, and PFA and FEP are particularly preferred in that a fluororesin coating having good melt fluidity and excellent surface smoothness is easily obtained.

The fluororesin may be used in any form of a dispersion in which fluororesin particles are dispersed in a liquid (liquid fluororesin paint) or a fluororesin powder (fluororesin powder paint). However, in the case of the dispersion, a small amount of impurities such as a surfactant is contained, which may remain after the film is formed, thereby making it difficult to remove the fluororesin film from the cylindrical mold. Becoming
It is preferable to use a fluororesin powder because the toner releasability of the fluororesin coating may decrease. The average particle size of the fluororesin powder is not particularly limited, but is preferably 15 μm or less, more preferably 10 μm or less, in order to form a uniform and thin film by powder coating. The lower limit is
Usually, it is about 1 μm. In particular, it is preferable to use PFA powder having an average particle diameter of 10 μm or less.

In order to apply the liquid fluororesin paint, the paint may be applied to the inner surface of a cylindrical mold, dried and fired according to a conventional method. To apply the fluororesin powder coating, various general-purpose powder coating methods can be adopted.
Among them, the use of the electrostatic coating method (electrostatic powder spraying method), in which the powder is charged and applied, forms a uniform, well-tightened coating powder layer on the inner surface of the cylindrical mold. It is preferable in doing. After a fluororesin coating is formed on the inner surface of the cylindrical mold by a powder coating method, the fluororesin is fired according to a conventional method. The thickness of the fluorinated resin film after firing is usually 0.1 mm.
It is about 1 to 150 μm, preferably about 1 to 100 μm, and more preferably about 5 to 40 μm.

In order to increase the adhesive strength between the fluororesin film and the belt base made of rubber or resin, it is preferable to etch the surface of the fluororesin film. As a method of etching the fluororesin film, a UV lamp,
Physical treatment (dry etching treatment) by irradiation such as ultraviolet irradiation, corona discharge, plasma treatment, electron beam irradiation, ion irradiation, and laser irradiation with an excimer lamp; chemical etching treatment with metallic sodium; wet etching treatment with a treatment liquid; And the like. By these etching treatments, fluorine atoms are extracted from the surface of the fluororesin film, or the surface is hydrophilized, so that the adhesive force between the fluorine resin film and the belt base made of a rubber or resin layer is increased. Further, an adhesive suitable for the material of the rubber or the resin layer can be applied to the surface of the fluororesin film.
After etching the fluororesin film, an adhesive may be applied.

The strength of the fluororesin coating is 100 kgf /
cm ² or more, preferably 200 kgf / cm
More preferably, it is ² or more. Further, the elongation of the fluororesin coating is more preferably 150% or more,
More preferably, it is at least 200%. Since the fluororesin coating has high strength and excellent toughness, a fluororesin-coated belt excellent in durability can be obtained. Preferably, a fluororesin coating having such high strength and elongation can be easily obtained by using a fluororesin powder coating.

In the present invention, a belt base made of rubber or resin is used. The belt substrate is formed as a rubber layer or a resin layer on a fluororesin coating formed on the inner surface of a mold using an uncured rubber material or a thermosetting or thermoplastic resin material. Examples of the rubber material include urethane rubber, silicone rubber, fluorine rubber, and EPDM rubber. As the rubber material which is easy to inject, liquid silicone which mixes and cures two liquids, and liquid urethane which mixes and cures polyol and isocyanate are preferable. As the rubber material, a thermoplastic elastomer may be used. As the urethane rubber, polyester-type and polyether-type polyurethane-based thermoplastic elastomers produced by a polyaddition reaction of a diisocyanate and a polyol are preferable. Examples of the silicone rubber include dimethyl silicone rubber, fluorosilicone rubber, methylphenyl silicone rubber, and vinyl silicone rubber. Vinylidene fluoride rubber,
Examples include tetrafluoroethylene-propylene rubber, tetrafluoroethylene-perfluoromethyl vinyl ether rubber, phosphazene-based fluororubber, and fluoropolyether. EPDM rubbers include those produced by polymerizing ethylene and propylene with a small amount of a third component in a hydrocarbon solvent using a Ziegler catalyst.
The resin material may be either thermosetting or thermoplastic, and includes, for example, polyester and nylon. Although urethane rubber is used in the examples, the invention is not particularly limited to urethane rubber.

The rubber or the resin may optionally contain an inorganic filler or an organic filler such as carbon black, mica and titanium oxide. The mixing ratio of the filler is usually 100 parts by weight with respect to 100 parts by weight of rubber or resin.
It is at most 80 parts by weight, preferably at most 80 parts by weight. Also,
Various additives such as a vulcanizing agent, a vulcanizing aid, a stabilizer and an antioxidant can be added to the rubber or the resin as required. The thickness of the rubber or resin layer (belt base) is appropriately set in consideration of the application, the structure of the machine to be installed, the target elasticity, the hardness of the material to be used, and the like.
It is about μm to 5 mm, preferably about 0.1 to 3 mm.

According to the method of the present invention, when the melting point of the fluororesin is Tf (° C.) and the thermal decomposition onset temperature of the rubber or the resin is Trp (° C.), the rubber or the resin having a Trf lower than Tf is used. Even when the belt base is manufactured, a fluorocarbon resin-coated belt that is integrally composited can be obtained without causing thermal deterioration of the belt base at the interface between the fluororesin coating and the belt base. Here, the pyrolysis onset temperature is measured with a thermogravimetric balance and defined as the temperature at which the weight loss exceeds 0.5%. The thermal decomposition start temperature is, for example, 1 for urethane rubber.
It is around 50 ° C and around 180 ° C for silicone rubber.
Therefore, rubber or resin having elasticity, flexibility, flexibility, and the like suitable for applications such as a transfer belt can be used. In a method in which a fluororesin paint is applied on a belt base made of rubber or resin and baked, the lower belt base is thermally degraded, so that the adhesive force at the interface between the fluororesin coating and the belt base is good and the belt base is integrally formed. A composite fluororesin-coated belt cannot be obtained. As shown in the sectional view of FIG. 1, the fluororesin-coated belt of the present invention has a fluororesin coating 2 on a belt base 1 made of rubber or resin.
Is a composite material having a layer configuration in which is formed.

In the method of manufacturing a fluororesin-coated belt of the present invention, (1) a fluororesin coating is formed on the inner surface of a cylindrical mold, and (2) the center of the cylindrical mold is aligned with the inner cavity. The core is inserted, and then (3) a rubber or resin material is injected into the gap between the fluororesin coating on the inner surface of the cylindrical mold and the core,
The rubber or resin layer is formed by curing or solidifying, whereby the fluororesin coating is integrally compounded on the belt base composed of the rubber or resin layer. After the molding, the fluororesin coating / belt base / core is released from the cylindrical mold, and then the core is pulled out to obtain a fluororesin-coated belt having a fluororesin coating / belt base layer structure. it can.

FIG. 2 shows an outline of the method for producing the fluororesin-coated belt of the present invention. As shown in the cross-sectional view of FIG. 2A, a fluororesin paint is applied to the inner surface of the cylindrical mold 3 and baked to form the fluororesin coating 2. Next, if desired, the surface of the fluororesin coating 2 is etched or
Apply the adhesive. The inner surface of the cylindrical mold is preferably subjected to a smoothing process in advance. Next, as shown in FIG. 2B, the core 4 is inserted into the hollow of the cylindrical mold 3 having the fluororesin coating 2 formed on the inner surface. It is preferable that a release agent is applied to the surface of the core 4. It is set so that the center of the cylindrical mold 3 and the center of the core 4 coincide.
That is, both axes are aligned.

Next, as shown in FIG. 2C, a rubber or resin material 1 is injected into a gap between the fluororesin coating 2 and the core 4 and cured or solidified to form a rubber or resin layer (belt base). ) Is formed. Injection of rubber or resin material
For example, a method of using a liquid rubber material or melting and casting a resin material is employed. In order to cure the rubber material or the thermosetting resin material, a heat treatment temperature and a heat treatment time suitable for each curing condition may be adopted. For injection of rubber or resin, injection, extrusion,
An appropriate method such as casting can be adopted. In addition,
Although not shown, one end or both ends of the cylindrical mold are usually sealed when the rubber or resin is injected or cured.

As shown in FIG. 2D, after the rubber or resin material is cured or solidified, the core 4 together with the fluororesin coating 2 and the rubber or resin layer 1 is removed from the cylindrical mold. FIG. 2E shows the fluororesin-coated belt with a core after the mold is released. Next, if the core 4 is removed, a fluororesin-coated belt in which the fluororesin coating 2 is formed on the belt base 1 can be obtained. According to this manufacturing method, the fluororesin can be sufficiently fired to obtain a fluororesin coating film having high film strength and elongation. Further, the rubber or resin of the belt base is not exposed to the sintering temperature of the fluororesin, and does not deteriorate due to heat.

[0026]

The present invention will be described more specifically below with reference to examples and comparative examples. [Example 1] The inner surface of a stainless steel cylinder (die) having an inner diameter of 80 mmφ and a length of 300 mm was chrome-plated,
Applying a fluororesin powder dispersion paint (AD2-CR manufactured by Daikin Co.) to the formed chrome-plated surface,
After drying at 100 ° C. for 30 minutes, heat treatment was performed at 380 ° C. for 30 minutes to form a 20 μm-thick fluororesin film. The strength of the fluororesin coating thus formed is 100 k
At gf / cm ² , the elongation was 150%. On the other hand, a release agent (molded spat manufactured by Asahi Glass Co., Ltd.) was applied to the surface of an aluminum core having an outer diameter of 76 mm and a length of 300 mm. An aluminum core coated with a release agent was inserted into the bore of the stainless steel cylinder on which the fluororesin coating was formed, and the two were set so that their axes coincided. In the gap between the stainless steel cylinder and the aluminum core, liquid urethane (SBU polyol 0 manufactured by Sumitomo Bayer Urethane Co., Ltd.)
620 + SBU isocyanate 0389),
The liquid urethane was cured by heat treatment at 120 ° C. for 60 minutes. Thereafter, the urethane rubber layer integrated with the fluororesin coating and the aluminum core were released from the stainless steel cylinder, and then the aluminum core was removed to obtain a fluororesin-coated belt.

On the fluororesin-coated belt thus obtained, four color toners (cyan, magenta, yellow, and black toners) of a laser beam printer manufactured by Canon Inc. were negatively charged. .1 g each. Plain paper was placed on the paper, and a positive charge was applied from the back of the paper, and negatively charged toner was adhered to the paper by Coulomb force. As a result, the entire amount of the toner was transferred to the paper, and no stain was generated on the belt. This was repeated 100 times, but in any case, the entire amount of the toner was transferred to the paper, and the belt was not stained. Further, when this operation was repeated up to 1000 times, the toner was slightly stained on the belt from the 500th time. However, an offset phenomenon in which the stain was transferred to paper and a double image was formed did not occur. Further, at the 500th time, although a part occurred between the urethane rubber layer and the fluororesin coating, there was no problem in transferring the toner to the paper.

Example 2 Inner diameter 80 mmφ, length 300
chrome-plated on the inner surface of a stainless steel cylinder (mold) having a diameter of 1 mm.
0 μm PFA fluororesin powder (MP-1 manufactured by DuPont)
02) was powder-coated and heat-treated at 380 ° C. for 30 minutes to form a 20 μm thick fluororesin coating. The strength of this fluororesin coating is 200 kgf / cm ² and the elongation is 200 kgf / cm ^2.
%Met. On the other hand, a release agent (molded spat manufactured by Asahi Glass Co., Ltd.) was applied to the surface of an aluminum core having an outer diameter of 76 mm and a length of 300 mm. An aluminum core coated with a release agent was inserted into the bore of the stainless steel cylinder on which the fluororesin coating was formed, and the two were set so that their axes coincided. In the gap between the stainless steel cylinder and the aluminum core, liquid urethane (SBU polyol 0620 manufactured by Sumitomo Bayer Urethane Co., Ltd. + SBU isocyanate 0)
389) and heat-treated at 120 ° C. for 60 minutes to harden the liquid urethane. Thereafter, the urethane rubber layer integrated with the fluororesin coating and the aluminum core were released from the stainless steel cylinder, and then the aluminum core was removed to obtain a fluororesin-coated belt.

On the fluororesin-coated belt thus obtained, four color toners (cyan, magenta, yellow, and black toners) of a laser beam printer manufactured by Canon Inc. were negatively charged. .1 g each. Plain paper was placed on the paper, and a positive charge was applied from the back of the paper, and negatively charged toner was adhered to the paper by Coulomb force. As a result, the entire amount of the toner was transferred to the paper, and no stain was generated on the belt. This was repeated 1000 times. In all cases, the entire amount of the toner was transferred to the paper, and the belt was not stained. Further, at the 500th time, although a part occurred between the urethane rubber layer and the fluororesin coating, there was no problem in transferring the toner to the paper.

Example 3 Inner diameter 80 mmφ, length 300
chrome-plated on the inner surface of a stainless steel cylinder (mold) having a diameter of 1 mm.
0 μm PFA fluororesin powder (MP-1 manufactured by DuPont)
02), and heat-treated at 380 ° C. for 30 minutes.
A fluororesin film having a thickness of 20 μm was formed. The strength of this fluororesin coating is 200 kgf / cm ² and the elongation is 20 kgf / cm ^2.
It was 0%. An etching solution (Tetra etch solution manufactured by Junko Co., Ltd.) was applied to the surface of the fluororesin film, washed with water, and subjected to an etching process. Next, a silicone-based adhesive (DY39-012, manufactured by Dow Corning Toray Silicone Co., Ltd.) was applied to the etched surface and air-dried. on the other hand,
A release agent (molded spat manufactured by Asahi Glass Co., Ltd.) was applied to the surface of an aluminum core having an outer diameter of 76 mm and a length of 300 mm. An aluminum core coated with a release agent was inserted into the bore of the stainless steel cylinder on which the fluororesin coating was formed, and the two were set so that their axes coincided. Liquid urethane (SBU polyol 0620 + SBU isocyanate 0389 manufactured by Sumitomo Bayer Urethane Co., Ltd.) was poured into the gap between the stainless steel cylinder and the aluminum core, and the liquid urethane was cured by heat treatment at 120 ° C. for 60 minutes. Thereafter, the urethane rubber layer integrated with the fluororesin coating and the aluminum core were released from the stainless steel cylinder, and then the aluminum core was removed to obtain a fluororesin-coated belt.

On the fluororesin-coated belt thus obtained, four color toners (cyan, magenta, yellow, and black toners) of a laser beam printer manufactured by Canon Inc. were negatively charged. .1 g each. Plain paper was placed on the paper, and a positive charge was applied from the back of the paper, and negatively charged toner was adhered to the paper by Coulomb force. As a result, the entire amount of the toner was transferred to the paper, and no stain was generated on the belt. This was repeated 1000 times. In all cases, the entire amount of the toner was transferred to the paper, and the belt was not stained. No peeling occurred between the urethane rubber layer and the fluororesin coating.

[Comparative Example 1] Inner diameter 80 mmφ, length 300
A release agent (Mold Spat, manufactured by Asahi Glass Co., Ltd.) was applied to the inner surface of a stainless steel cylinder (mold) having a diameter of 2 mm. On the other hand, the outer diameter 76
A release agent (Mold Spat manufactured by Asahi Glass Co., Ltd.) was applied to the surface of a 300 mm long, 300 mm long aluminum core. An aluminum core coated with a release agent was inserted into the inner cavity of the stainless steel cylinder coated with the release agent, and set so that the axes of the two were aligned. In the gap between the stainless steel cylinder and the aluminum core, liquid urethane (SBU polyol 0620 + SBU manufactured by Sumitomo Bayer Urethane Co., Ltd.)
Isocyanate 0389) is poured thereinto at 120 ° C. for 60 minutes.
The liquid urethane was cured by a heat treatment for one minute. Thereafter, the urethane rubber layer and the aluminum core were released from the stainless steel cylinder, and then the aluminum core was removed to obtain a urethane rubber belt. On the urethane rubber belt thus obtained, four color toners (cyan, magenta, yellow, and black toners) of a laser beam printer manufactured by Canon Inc. were negatively charged, and 0.1 g each was placed thereon. . Plain paper was placed on the paper, and a positive charge was applied from the back of the paper, and negatively charged toner was adhered to the paper by Coulomb force. As a result, 90% of the toner was transferred to paper,
10% remained on the urethane rubber belt, and the belt was stained. Further, when this operation was repeated 10 times, dirt was generated on the entire surface of the belt, and the dirt was transferred to paper to cause double reflection.

Comparative Example 2 Inner diameter 80 mmφ, length 300
A release agent (Mold Spat, manufactured by Asahi Glass Co., Ltd.) was applied to the inner surface of a stainless steel cylinder (mold) having a diameter of 2 mm. On the other hand, the outer diameter 76
A release agent (Mold Spat manufactured by Asahi Glass Co., Ltd.) was applied to the surface of a 300 mm long, 300 mm long aluminum core. An aluminum core coated with a release agent was inserted into the inner cavity of the stainless steel cylinder coated with the release agent, and set so that the axes of the two were aligned. In the gap between the stainless steel cylinder and the aluminum core, liquid urethane (SBU polyol 0620 + SBU manufactured by Sumitomo Bayer Urethane Co., Ltd.)
Isocyanate 0389) is poured thereinto at 120 ° C. for 60 minutes.
The liquid urethane was cured by a heat treatment for one minute. After that, the urethane rubber and aluminum core were released from the stainless steel cylinder, and then the aluminum core was pulled out.
A urethane rubber belt was obtained. A fluororesin dispersion paint (AD manufactured by Daikin Co., Ltd.) is placed on the urethane rubber belt.
2-CR), and dried at 100 ° C. for 30 minutes.
Heat treatment was performed at 0 ° C. for 30 minutes to form a fluororesin film having a thickness of 20 μm. As a result, a fluororesin film could be formed, but the urethane rubber belt was thermally degraded, deformed, cracked and broken, and the shape of the belt could not be maintained.

[0034]

According to the present invention, there is provided a fluororesin-coated belt in which a fluororesin coating is formed on a belt substrate made of rubber or resin, wherein there is no thermal deterioration at the interface between the belt substrate and the fluororesin coating. Both are integrally combined to provide a fluororesin-coated belt having excellent durability. According to the present invention, there is provided a fluororesin-coated belt suitable as a transfer belt which prevents surface contamination due to toner sticking and does not cause double appearance of an image. Further, according to the present invention, there is provided a method for producing a fluororesin-coated belt capable of forming a fluororesin coating having excellent mechanical properties on the belt substrate without deteriorating the rubber or resin constituting the belt substrate. Is done. The fluororesin-coated belt of the present invention is
Although it can be applied to a wide range of uses such as conveyance, it is particularly suitable as various belts including a transfer belt in an image forming apparatus such as an electrophotographic copying machine or a printer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer configuration of a fluororesin-coated belt of the present invention.

FIG. 2 is a process chart showing a method for producing a fluororesin-coated belt of the present invention.

[Explanation of symbols]

 1: Belt base made of rubber or resin 2: Fluororesin coating 3: Cylindrical mold 4: Core 5: Fluororesin-coated belt with removed core

Continued on the front page (72) Inventor Yoshitaka Ikeda, 950 Noda, Oaza, Kumatori-cho, Sennan-gun, Osaka Sumitomo Electric Industries, Ltd. (72) Inventor Chiaki Kato 950 Noda, Kazatori-cho, Sennan-gun, Osaka F-term (reference) 2H032 BA09 BA18 DA13 4F213 AA16 AA45 AD15 AG03 AG08 AG16 AH12 WA02 WA03 WA43 WA54 WA63 WB13 WC02

Claims (5)

[Claims] 1. A fluororesin-coated belt in which a fluororesin film is formed on a belt base made of rubber or resin, wherein a thermal decomposition start temperature (Trp) of the rubber or resin is lower than a melting point (Tf) of the fluororesin, And a fluororesin-coated belt, wherein the belt base and the fluororesin coating are integrally compounded. 2. The strength of the fluororesin coating is 100 kgf /
² cm or more, and elongation is 150% or more.
The fluororesin-coated belt according to the above. 3. A method of manufacturing a fluororesin-coated belt in which a fluororesin coating is formed on a belt base made of rubber or resin, wherein (1) forming a fluororesin coating on the inner surface of a cylindrical mold; The core is inserted with the axis aligned with the bore of the cylindrical mold, and then (3) a rubber or resin material is injected into the gap between the fluororesin coating on the inner surface of the cylindrical mold and the core. Curing or solidifying to form a rubber or resin layer, whereby the fluororesin coating is integrally compounded on a belt base made of the rubber or resin layer, thereby producing a fluororesin-coated belt. 4. The process for producing a fluororesin-coated belt according to claim 3, wherein in the step (1), a fluororesin powder is powder-coated on the inner surface of the cylindrical mold and baked to form a fluororesin coating. Method. 5. The method for producing a fluororesin-coated belt according to claim 3, wherein after forming the fluororesin coating, the surface of the fluororesin coating is further etched.