JP2001305891A - Seamless belt, image forming apparatus belt and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seamless belt that includes carbon black and has a good appearance without any foamed imperfection and deterioration of mechanical performance due to the resin degradation by suppressing the resin degradation, an image forming apparatus belt using this seamless belt, and an image forming apparatus using this image forming apparatus belt. SOLUTION: The seamless belt is formed by shaping a composition which includes carbon black, synthetic resin and at least one kind material selected among silane coupling material, aluminate coupling material, titanate coupling material and zirconate coupling material. The image forming apparatus belt employs the seamless belt, and the image forming apparatus employs the image forming apparatus belt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless belt made of synthetic resin containing carbon black, and an intermediate transfer using the seamless belt for an electrophotographic copying machine, a laser beam printer, a facsimile machine and the like. The present invention relates to a belt for an image forming apparatus such as a belt, a transfer belt, and a photoreceptor belt, and an image forming apparatus including the belt for the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus such as an OA apparatus, an electrophotographic system using a photoconductor and toner, and a toner jet system in which toner is directly transferred onto a seamless belt without using a photoconductor have been devised and marketed. Have been. These devices include conductive, semi-conductive, and insulating materials such as photoreceptor belts, intermediate transfer belts, transfer transfer belts, transfer separation belts, charging tubes, developing sleeves, fixing belts, and toner transfer belts, regardless of the presence or absence of seams. A seamless belt controlled to various electrical resistances is used.

[0003] For example, an intermediate transfer device is configured to once form a toner image on an intermediate transfer body and then transfer the toner to paper or the like. A seamless belt made of a seamless belt is used for charging and removing the toner on the surface layer of the intermediate transfer member. This seamless belt is set (conductive, semiconductive, and insulated) to different surface electrical resistance and electrical resistance in the thickness direction (volume electrical resistance) for each machine model.

In addition, the transfer device transfers the toner from the photoreceptor onto the paper held on the transfer member after the paper is once held on the transfer member, and further separates the paper from the transfer member by removing static electricity. It is configured as follows. There is a seam on the surface of the transfer transfer body for charging and discharging the paper.
No seamless belt is used. As described above, this seamless belt is set to have different surface electric resistance and electric resistance in the thickness direction (volume electric resistance) for each machine model.

FIG. 1 is a side view of an electrophotographic apparatus using an intermediate transfer belt formed of a conventional seamless belt. In the figure, 1 is a photosensitive drum, and 6 is a conductive seamless belt. An electrophotographic process unit including a charger 2, an exposure optical system 3 using a semiconductor laser or the like as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged. The conductive seamless belt 6 includes transport rollers 7, 8,
9, and moves in the direction of the arrow in synchronization with the photosensitive drum rotating in the direction of the arrow.

Next, the operation will be described. First, arrow A
The surface of the photosensitive drum 1 rotating in the direction is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device or the like (not shown) is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. The toner image is electrostatically transferred to the conductive seamless belt 6 by the electrostatic transfer machine 10 and the transfer roller 9
And between the pressing roller 12 and the recording paper 11.

In the case of a conductive seamless belt of an image forming apparatus such as an electrophotographic copying machine, a sufficient durability is required because the belt is driven by two or more rolls at a high tension for a long time. You. Further, when used in an intermediate transfer device or the like, an image is formed with a toner on a belt and transferred to paper. Therefore, if the belt is loosened or stretched at the time of driving, an image shift may be caused. In addition, since the toner is transferred electrostatically, a certain degree of conductivity is required.

Such a seamless belt is an important component for determining a toner image, and is considered as one of the three major components together with the photoreceptor and toner.

Therefore, the following items are required for the intermediate transfer belt. The semiconductor region has predetermined surface resistivity and volume resistivity. Must have toner release properties. The thickness is thin and uniform. Strong mechanical strength (hard to break). The resistance value does not fluctuate due to the environment (temperature and humidity). Low cost. The belt must be seamless and round.

Further, with the recent high-speed printing of machines, the driving speed of the belt has been increased, and it has been necessary to improve the durability of the belt.

In particular, a tandem type transfer / intermediate transfer belt or a toner jet belt in which four photoconductors are arranged has attracted attention because it can print at high speed, and durability and image misalignment are particularly important. .

Until now, seamless belts include, for example, polyamide, polyimide, polyvinylidene fluoride,
In a resin composition such as an ethylene tetrafluoroethylene copolymer, polycarbonate, or polyester, carbon black such as acetylene black, furnace black, or channel black is added, and molded into a thickness of about several tens to several hundreds μm. Thus, it is known that a belt set to a predetermined electric resistivity (surface resistivity, volume resistivity) is obtained as an intermediate transfer body belt, and a transfer belt for transferring paper and transferring toner. JP-A-63-31267
JP, JP-A-5-170946, JP-A-6-2
The following method is considered as a method for producing a seamless belt.

(I) Rotational molding method (also sometimes referred to as centrifugal molding method) A resin in which a solution is dissolved is put into the inner peripheral surface of a cylindrical mold, and a temperature is applied while rotating the mold to remove the solvent. The process consists of removing the seamless tube from the inside of the mold after volatilizing by half or more, and attaching the seamless tube to the outside of another cylindrical mold and applying a temperature to cause a thermosetting reaction (particularly). JP-A-60-170862). This method is mainly used for manufacturing a polyimide transfer belt.

(Ii) Extrusion molding method This is a method in which a resin in which a conductive filler is compounded is melt-extruded in a ring shape. This method is mainly used for producing a transfer belt of ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, polycarbonate, polyester, or polyimide.

(Iii) Dipping method This is a method in which a resin solution is applied to the outer surface of a cylindrical or cylindrical mold by dipping or the like to have a constant thickness, and a film is formed by heating, and then the tubular film formed from the mold is pulled out. .
This method is mainly used for producing a polyvinylidene fluoride transfer film.

(Iv) Rubber Extrusion Molding Method A method has been reported in which a polyurethane rubber is extruded into a tubular shape, vulcanized, polished, and then the outer layer surface is coated with a fluororesin or the like (Journal of the Electrophotographic Society 33 (1)). ) 43 (199
4)).

Conventionally, as such a conductive seamless belt, a belt formed by blending a conductive filler such as carbon black with a thermosetting resin or a thermoplastic resin is mainly used. Among them, those containing a thermoplastic resin as a main component are easy to continuously mold and have been widely used. Among thermoplastic resins, thermoplastic amorphous resins are more excellent in dimensional accuracy than thermoplastic crystalline resins. As such a seamless belt made of a thermoplastic amorphous resin, for example, a conductive resin such as a polycarbonate resin is blended with conductive carbon black, and extruded into a cylindrical film using a cylindrical die. Is known (for example, Japanese Patent Laid-Open Publication No. 3-89357).

Amorphous thermoplastic resin is superior in dimensional accuracy to thermoplastic crystalline resin, but is inferior in bending resistance. For example, when used for electrophotography as an intermediate transfer belt, cracking occurs during use. Is easy to occur. In order to solve this problem, a seamless belt comprising a mixture of polycarbonate and a polyalkylene terephthalate such as polybutylene terephthalate has been proposed (Japanese Patent Application Laid-Open Nos. 4-313775 and 6-149083). .

[0019]

As described above, in order to impart conductivity to a seamless belt, carbon black is dispersed in a thermoplastic resin.

In general, carbon black has many impurities and functional groups on its surface, and when melt-processed together with a thermoplastic resin, the impurities and functional groups on the surface promote the thermal decomposition of the thermoplastic resin, so that the molecular weight of the thermoplastic resin decreases. It is said to cause poor appearance such as deterioration of physical properties and foaming.

In order to solve these problems, carbon black having a small number of functional groups on the surface has been proposed, melt processing of the resin composition has been carried out at a low temperature, and the melting time has been shortened. The effect has been obtained.

However, carbon black having a small number of functional groups on the surface does not have sufficient affinity with the resin, and in some cases, it may not be possible to obtain desired conductive properties. Therefore, the temperature and time of melt processing of the resin composition are limited. Then, it was insufficient such that it could not be dispersed or the shape that could be formed was limited as expected.

It is an object of the present invention to provide a seamless belt with less thermal decomposition and foaming during melt processing.

[0024]

The seamless belt of the present invention comprises at least one member selected from the group consisting of a silane coupling agent, an aluminate coupling agent, a titanate coupling agent and a zirconate coupling agent. It is characterized by comprising a composition comprising a coupling agent, carbon black and a synthetic resin.

It has been found that the presence of a specific coupling agent significantly suppresses the thermal decomposition of synthetic resins, particularly thermoplastic resins, during melt processing.

It is to be noted that the coupling agent and the carbon black may be brought into contact with each other prior to blending the carbon black into the synthetic resin, or the coupling agent and the carbon black may be separately blended into the synthetic resin. Good. However, it is preferable that carbon black is brought into contact with the coupling agent in advance so that the effect of the coupling agent can be sufficiently exerted even in a small amount. Specifically, it is preferable to dissolve the coupling agent in a solvent to form a solution, contact the solution with carbon black (carbon black powder or slurry), and then dry the solution.

The seamless belt of the present invention is used in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, and a facsimile machine as an intermediate transfer belt, a transfer belt, and a photosensitive belt.

The belt for an image forming apparatus of the present invention is an intermediate transfer belt, a transport transfer belt or a photosensitive belt made of the seamless belt.

The image forming apparatus of the present invention comprises the belt for the image forming apparatus.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

(1) First, the composition constituting the seamless belt of the present invention will be described. The seamless belt of the present invention needs to contain a synthetic resin, carbon black, and a specific coupling agent, and more preferably contains fluorine. The properties of each are as follows. (Carbon black) <Types of carbon black>

The type of carbon black used in the present invention is not particularly limited, and examples thereof include channel black, acetylene black, furnace black and the like, and these can be used alone or in combination.

<Specific surface area> The carbon black used in the present invention is intended to exhibit conductivity. Generally, the larger the specific surface area of carbon black, the lower the powder resistance,
Since the conductivity is easily developed, it is preferable that the specific surface area is large in order to develop the conductivity by adding a small amount of carbon black. Specifically, the measured value by the BET method is 10 m ² / g.
Or more, more preferably 50 m ² / g or more.

On the other hand, if the specific surface area is too large, poor dispersion of carbon black in the resin will occur or the contact area with the resin per unit weight of carbon black will increase, resulting in the catalytic action of carbon black. There is a problem that a decomposition reaction of the resin occurs. Preferably 1000 m ² / g or less specifically, particularly preferably is not more than ^{500m 2 / g, 80~400m 2 /} g being most preferred.

In the case of carbon black having a relatively large specific surface area, the decomposition reaction of the resin is apt to occur if used without treatment with alkylsilane or the like. The decomposition reaction of the resin can be greatly suppressed.

<Particle Size> Although there is no particular limitation on the particle size of carbon black, carbon black having a small particle size generally has a large specific surface area, high conductivity, and is liable to cause a resin decomposition reaction. The range in which the effects of the invention can be most effectively exhibited is, for example, 15 to 40 nm.

<DBP Oil Absorption> Although there is no particular limitation on the DBP oil absorption, carbon black used in the present invention is intended to exhibit conductivity, and generally, the larger the DBP oil absorption, the higher the powder resistance. Is low, and conductivity is easily developed. Therefore, in order to develop conductivity by adding a small amount of carbon black, it is preferable that the DBP oil absorption is large. Specifically, the DBP oil absorption according to JIS K6221 is preferably 35 mL / 100 g or more, and 45 mL / 10
More preferably, it is 0 g or more.

Further, carbon black having an excessively large DBP oil absorption may cause dispersion failure in the resin over time. Therefore, it is preferable that the carbon black is somewhat small, specifically, 500 mL / 100 g or less, more preferably 300 mL / 100 g or less. 1
00 g or less, more preferably 200 mL / 10
It is particularly preferred that the amount be 0 g or less.

<Volatile Content> In general, the carbon black surface has functional groups such as a hydroxyl group and a carboxylic acid group, and these are considered to promote the deterioration of the resin at a high temperature such as melt processing of the resin. Carbon black having more of these functional groups promotes the deterioration of the resin, so that the suppression effect of the present invention is remarkably obtained. In addition, although carbon black having a small number of functional groups does not promote deterioration of the resin, it has a low affinity at the interface with the resin, which causes poor dispersion or mechanical properties of the resin composition. In some cases, carbon black having a functional group to some extent is more preferable.

The hydroxyl group and carboxylic acid group are converted into water, carbonic acid and the like by heating, so that the amount of the functional group can be evaluated by measuring the volatile content.

In order for the effects of the present invention to be effectively exhibited, the volatile content is preferably at least 1%, more preferably at least 3%, particularly preferably at least 5%.

If the volatile matter content is too large, a sufficient effect may not be obtained. Specifically, it is preferably at most 20%, more preferably at most 15%, particularly preferably at most 10%.

<Blending Amount of Carbon Black> The appropriate blending amount of carbon black in the composition varies depending on the conductivity of carbon black, the desired resistance level, and the production conditions, and cannot be unconditionally specified, but the blending amount is small. If it is too high, conductivity may not be sufficiently exhibited, so that the content is preferably 3% by weight or more, and more preferably 10% by weight or more. Further, if the amount is too large, the mechanical properties of the resin composition may be deteriorated. Therefore, it is preferable that the amount is small to some extent, specifically, 30% by weight or less, and 20% by weight.
It is more preferable that the following is satisfied.

The carbon black used may be one type or two or more types.

(Coupling Agent) <Type of Coupling Agent> The coupling agent is at least one selected from silane-based, aluminate-based, titanate-based, and zirconate-based coupling agents. The following can be suitably used.

Silane-based coupling agent The silane-based coupling agent is, for example, one represented by the following general formula. (R-) _n -Si-X _4-n

In the above general formula, R represents an alkyl group which may be substituted, and X represents a hydroxyl group, an alkoxy group or a halogen.

When R has reactivity with a resin such as an epoxy group or an amino group, it may be referred to as "silane coupling agent", and when R does not, it may be referred to as "alkylsilane". Both are referred to as silane coupling agents.

Among the silane coupling agents, X is preferably an alkoxy group from the viewpoint of binding to carbon black. Among the alkoxy groups, X represented by the following formula is a methoxy group and n is Those which are 1 are particularly preferred. _{R-Si - (- OCH 3} ) 3

This is because when X is a hydroxyl group, the reactivity is too high,
This is because an alkoxy group having a larger number of carbon atoms than an ethoxy group has too large a steric hindrance, so that Si may not be able to approach functional groups on the surface of carbon black.

It is particularly preferable that R represented by the following formula is an alkyl group substituted with fluorine, in view of the excellent balance between reactivity and stability. _{CF 3 (CF 2) m CH} 2 CH 2 -Si - (- OC
H ₃ ) ₃

The reason why the fluorinated compound is preferable is that the reactivity with other functional groups which can cause adverse effects is small. Further, when the perfluoroalkyl group is directly bonded to Si, it is thermally unstable due to the influence of steric hindrance and is easily decomposed. Therefore, it is more preferable that the perfluoroalkyl group is via an ethylene group as described above.

These alkylsilanes can be easily obtained on the market.

For example, KBM- manufactured by Shin-Etsu Chemical Co., Ltd.
7103 {CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ } can be easily obtained from the market.

Aluminate coupling agent The aluminate coupling agent is, for example, one represented by the following general formula. Note that R ¹ , R ² , R ³ , R ⁴ , R
⁵ is an alkyl group or hydrogen, and an arrow ← indicates a coordination bond.

[0056]

Embedded image

Such an aluminate-based coupling agent can be obtained as a commercial product such as AL-M manufactured by Ajinomoto Co., Inc.

Titanate-based coupling agent The titanate-based coupling agent is, for example, one represented by the following general formula. Note that R ¹ and R ² are an alkyl group or hydrogen, and a + b = 4.

[0059]

Embedded image

Such a titanate-based coupling agent can be obtained as a commercial product, such as Plenact from Ajinomoto Co., Inc.

Zirconate Coupling Agent The zirconate coupling agent is, for example, one represented by the following general formula. Note that R ¹ , R ² , R ³ , and R ⁴ are an alkyl group or hydrogen.

[0062]

Embedded image

Such a zirconate-based coupling agent can be obtained as a commercial product such as ZR-181 manufactured by Nippon Soda Co., Ltd.

<Effects of Coupling Agent> It is not clear why the above-described specific coupling agent can suppress the phenomenon of promoting deterioration during melt processing by blending carbon black with the resin composition, but the following is given. It is thought that it depends on the mechanism.

That is, it is considered that the promotion of the deterioration of the resin composition during the melt processing by the blending of the carbon black is due to the adverse effect of the functional groups on the surface of the carbon black. The coupling agent is adsorbed on a functional group on the surface of the carbon black, or, as a result of forming a chemical bond by causing a dehydration reaction or the like, the functional group on the surface of the carbon black is sealed,
It is considered that the carbon black does not adversely affect the synthetic resin.

<Coupling Agent Content> When the type of carbon black is the same, the number of functional groups on the surface of carbon black that can be sealed by the coupling agent is determined not by the weight of the coupling agent but by the molecular weight of the coupling agent. Depends on the number.

If the content of the coupling agent with respect to the carbon black is small, a sufficient effect cannot be obtained. Therefore, the content is preferably 0.001 mmol (mmol) or more, more preferably 0.01 mmol or more per 1 g of the carbon black.

If the number of coupling agents is too large,
Residual residues that cannot be completely reacted may adversely affect the resin at the time of melt processing. Therefore, it is preferable that the residual amount is small to a certain extent.
mol or less, more preferably 10 mmol or less.

(Production Method of Carbon Black Containing Coupling Agent) This production method is not particularly limited. For example, a carbon black solvent slurry is placed in a container equipped with a screw stirrer, and a small amount of the coupling agent solution is stirred. It is possible to adopt a method of adding each. As the solvent, methanol is preferable, for example, in consideration of dispersibility of carbon and the coupling agent and small side reaction with the coupling agent. Thereafter, by removing the solvent, a coupling agent-containing carbon black can be obtained.

When the solvent is removed, drying by heating or drying under reduced pressure is performed, whereby the coupling agent condenses with a functional group such as a hydroxyl group or a carboxylic acid on the surface of carbon black, thereby promoting the formation of a chemical bond. This is particularly preferred.

(Synthetic Resin) <Kind of Synthetic Resin> In the present invention, either a thermosetting resin or a thermoplastic resin can be used, but a thermoplastic resin is more preferable.

<Thermoplastic resin> As the thermoplastic resin, polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component such as ethylene Propylene copolymer rubber, styrene / butadiene rubber, styrene / butadiene / styrene / styrene block copolymer or its hydrogenated derivative, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyimide, liquid crystalline polyester , Polysulfone, polyphenylene sulfide, polybisamide triazole, polyetherimide, polyetheretherketone, acrylic, polyvinylidene fluoride, polyvinyl fluoride, chlorotri Ruoroechiren, ethylene tetrafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer,
1 of alkyl acrylate copolymer, polyester ester copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer, etc.
Those consisting of seeds or mixtures thereof can be used.

Among them, it is more preferable to select a thermoplastic resin which requires a high temperature during melt processing, since more effective effects can be obtained.

Specifically, a crystalline thermoplastic resin is more effective when a thermoplastic resin having a melting point of 180 ° C. or higher is used as an index, and is more preferably used at a temperature of 200 ° C. or higher. In the case of an amorphous thermoplastic resin, the melting point of the resin is not shown.
More preferably, the temperature is 30 ° C. or higher.

Among the thermoplastic resins, the polyester resin has an ester bond, and is easily decomposed by a hydroxyl group or a carboxylic acid group on the surface of carbon black.
It is more preferable to obtain the effects of the present invention. Among the polyester resins, polycarbonate and / or polyalkylene terephthalate are particularly preferred.

The polycarbonate is not particularly limited.
For example, a resin having a general molecular weight such as a weight-average molecular weight of 10,000 to 100,000 can be used, but when there is a demand for high mechanical properties such as tensile elongation at break, a high molecular weight resin is preferable. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and 3
It is particularly preferable that the concentration is not less than 000.

The polyalkylene terephthalate is not particularly limited, and PBT (polybutylene terephthalate) and PET (polyethylene terephthalate) are particularly preferred.
And PEN (polyethylene naphthalate) can be selected. Among them, PBT has a high crystallization rate, so that the change in crystallinity due to molding conditions is small. preferable.

The molecular weight of the polyalkylene terephthalate is not particularly limited. For example, the weight average molecular weight is 10,000.
A resin having a general molecular weight such as 100 to 100,000 can be used, but when there is a demand for high mechanical properties such as tensile elongation at break, a high molecular weight resin is preferable. Specifically, 2
It is preferably at least 000, more preferably at least 25,000, particularly preferably at least 30,000.

<Thermosetting resin> As the thermosetting resin,
For example, epoxy, polyimide, polyamide imide, poly merimide, melamine, phenol, unsaturated polyester, or a mixture thereof may be used.

(Polymerization catalyst) It is preferable to mix a polymerization catalyst and adjust the production conditions, because it is possible to promote the increase in the molecular weight and the alloy of the resin.

(Additive compounding agent; optional component) The resin composition may contain optional compounding components according to various purposes.

Specifically, the trade name is Irgaphos 168,
Antioxidants such as Irganox 1010, PEPQ
Other than heat stabilizers such as (trade name), various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, anti-fog agents, anti-blocking agents, slip agents, crosslinking agents, crosslinking assistants, and coloring agents ,
Various additives such as a flame retardant and a dispersant can be added.

Various fillers such as calcium carbonate (heavy and light), talc, mica, silica, alumina, aluminum hydroxide, zeolite, wollastonite, diatomaceous earth, glass fiber, glass beads, bentonite, asbestos, Hollow glass beads, graphite, molybdenum disulfide, titanium oxide, carbonate fiber, aluminum fiber, styrene steel fiber, brass fiber, aluminum powder, wood powder, rice hull, graphite, metal powder, conductive metal oxide, organometallic compound, In addition to fillers such as organic metal salts, additives such as antioxidants (phenol-based, sulfur-based, phosphate-based, etc.), lubricants, various organic and inorganic pigments, UV inhibitors, antistatic agents, dispersants, Examples thereof include a wetting agent, a foaming agent, a plasticizer, a copper damage inhibitor, a flame retardant, a crosslinking agent, and a flow improver.

(Heat Kneading) In the present invention, a seamless belt may be formed after heating and kneading carbon black, a synthetic resin and a polymerization catalyst to form a resin composition. The seamless belt can be obtained as it is by kneading.

The means for heating and kneading is not particularly limited, and various means can be used. For example, if a resin composition is prepared by heating and kneading a carbon black, a synthetic resin, and a polymerization catalyst, a single-screw extruder, a twin-screw kneading extruder, a Banbury mixer, a roll, a Brabender, a plastograph,
A kneader or the like can be used.

(Heat Treatment) By subjecting the obtained seamless belt to heat treatment, the physical properties can be further improved. In particular, the number of folding times and the tensile modulus are improved.

The heat treatment conditions depend on the starting resin used,
Usually a temperature of 60 to 200 ° C, preferably 70 to 120 ° C
At a temperature of 5 to 60 minutes, preferably about 10 to 30 minutes.

In order to obtain a seamless belt, a method of mixing a crystalline resin, an amorphous resin, and a polymerization catalyst with, for example, a twin-screw kneading extruder, forming a pellet, and then forming a seamless belt is preferably used. .

(Molding Method) The molding method is not particularly limited, and can be obtained by employing a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, or an inflation molding method. However, particularly preferred is a continuous melt extrusion process. In particular, an internal cooling mandrel method or a vacuum sizing method of a downward extrusion method capable of controlling the inner diameter of the extruded tube with high precision is preferable, and an internal cooling mandrel method is most preferable.

In the case of a thermosetting synthetic resin, for example, carbon black is dispersed in a solution of the synthetic resin, applied to the inner surface of a cylindrical cylinder, and the cylindrical cylinder is rotated by the centrifugal force to form the cylindrical resin. Centrifugal molding for obtaining a seamless belt can be mentioned (see Japanese Patent Application Laid-Open No. 5-77252). Further, for example, by dissolving a solvent-soluble synthetic resin in a solvent, dispersing carbon black, applying this liquid on a metal cylindrical body, drying, and then extracting the cylindrical body to obtain a cylindrical seamless belt. A dipping method can be cited (see Japanese Patent Application Laid-Open No. 7-092525).

Further, by adjusting the temperature and the residence time during the molding, a seamless belt having better physical properties can be obtained. Therefore, it is preferable to adjust the conditions in accordance with each composition.

The seamless belt of the present invention may be used as it is, or may be used by winding it around a drum or a roll.

Further, for the purpose of preventing meandering and reinforcing the end surface, a heat-resistant tape is adhered around the inside and / or outside end of the seamless belt having a predetermined size, or a tape such as urethane rubber or silicone rubber is attached to the belt. It may be bonded near the inner end.

(Surface Resistivity) The seamless belt of the present invention may optionally contain a conductive filler or a substance exhibiting conductivity.

Although the resistance region varies depending on the purpose, the surface resistivity is 1 × 10 ⁰ to 1 × 10 ¹⁶ Ω or the volume resistivity is 1 × 10 ¹⁶ Ω.
It is selected from the range of ⁰ to 1 × 10 ¹⁶ Ω · cm.

The preferable range varies depending on the application. For example, when the belt is used as a photoreceptor belt, the surface resistivity is from 1 × 10 ⁰ to allow the charge on the outer surface to escape to the inner surface.
1 × 10 ⁹ Ω or volume resistivity 1 × 10 ⁰ to 1 × 10 ⁹ Ω
· A resistivity as low as 1 cm is preferable, and when used as an intermediate transfer belt, a surface resistivity of 1 which can be easily charged and transferred.
× 10 ⁶ to 1 × 10 ¹³ Ω or volume resistivity 1 × 10 ⁶ to
1 × 10 ¹³ Ω · cm is preferable, and when used as a transporting transfer belt, it is easily charged and hardly damaged even at a high voltage, and is 1 × 10 ¹⁰ to 1 × 10 ¹⁶ Ω or volume resistivity 1 × 10
^{10 ~1 × 10 1 6 Ω ·} cm and a high region is preferred.

The distribution of the surface resistivity in one seamless belt is preferably narrow. In each of the preferable surface resistivity regions, the difference between the maximum value and the minimum value in one belt is two.
It is preferable that the value is within the order of magnitude (the maximum value is 100 times or less of the minimum value).

The surface resistivity and volume resistivity of the film can be easily measured by, for example, Hiresta and Loresta manufactured by Dia Instruments Co., Ltd. and R8340A manufactured by Advantest Co., Ltd.

(Thickness of Seamless Belt) If the thickness of the seamless belt is excessively large, the deformation difference between the outer side and the inner side of the belt becomes large and the belt is easily broken when the curvature with the roller is large. Further, the toner transferred to the outer portion is deformed and scattered, so that the image is deformed. On the other hand, if the thickness of the seamless belt is excessively small, cracks tend to occur due to a small amount of dust entering between the roller and the belt, or scratches due to contact with the photoreceptor or the like, and the belt is easily damaged. Therefore, the thickness of the seamless belt needs to be 70 to 300 μm, and particularly preferably 100 to 200 μm.

(Use of Seamless Belt) The use of this seamless belt is not particularly limited, but it is preferably used in the field of OA equipment which has strict required physical properties such as dimensional accuracy, flex resistance and tensile elongation at break, especially for functional members. it can. If this seamless belt is made into a seamless belt shape,
This is suitable because there are few defects such as elongation.

This seamless belt can be suitably used, for example, as an intermediate transfer belt, a transfer belt, and a photosensitive belt for electrophotography.

A reinforcing tape may be attached to the seamless belt along the side edges as necessary. As the reinforcing tape, a biaxially stretched polyester tape is preferable in terms of cost and strength, and a tape width of 4 mm or more and 20 mm or less is preferable because the apparatus layout becomes compact. The thickness of the reinforcing tape is preferably 20 μm or more and 200 μm or less in order to maintain the flexibility and to drive the seamless belt with a low tension and prevent cracks from occurring.

[0103]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples. The materials used in the following examples and comparative examples are as follows.

(Carbon black) Carbon black containing no coupling agent (hereinafter abbreviated as CB-A) MA100 manufactured by Mitsubishi Chemical Corporation Specific surface area 110 m ² / g, DBP oil absorption 100 mL /
100 g, primary particle size: 24 nm ・ 500 g of carbon black CB-A containing a silane coupling agent and 1 L of methanol were mixed at 6000 rpm for 30 minutes using a homomixer to prepare a slurry. On the other hand, KBM-7103 @ CF manufactured by Shin-Etsu Chemical Co., Ltd.
15 g of ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ was dissolved in 150 mL of methanol to prepare an alkylsilane solution. The slurry was transferred to a container equipped with a screw-type stirrer, and the above-mentioned alkylsilane solution was added little by little under a stirring condition of about 1000 rpm. After stirring for about 15 minutes, the resultant was dried with a reduced pressure drier equipped with a trap at 1 mmHg at 70 ° C. for 7 hours to remove methanol (the obtained carbon black is abbreviated as CB-X1).

A slurry was prepared by mixing 500 g of carbon black CB-A containing an aluminate coupling agent and 1 L of methanol at 6000 rpm for 30 minutes using a homomixer. On the other hand, 15 g of Ajinomoto's AL-M
It was dissolved in 50 mL to prepare an AL-M solution. Transfer the slurry to a container with a screw-type stirrer,
The above AL-M solution was added little by little under the stirring condition of rpm. After stirring for about 15 minutes, the resultant was dried with a reduced pressure drier equipped with a trap at 1 mmHg at 70 ° C. for 7 hours to remove methanol (the obtained carbon black is abbreviated as CB-X2).

A slurry was prepared by mixing 500 g of carbon black CB-A containing a titanate coupling agent and 1 L of methanol using a homomixer at 6000 rpm for 30 minutes. On the other hand, a TTS solution was prepared by dissolving 45 g of Ajinomoto Co., Inc. Plenact TTS in 150 mL of methanol.
The slurry was transferred to a container equipped with a screw-type stirrer, and the TTS solution was added little by little under stirring conditions of about 1000 rpm. After stirring for about 15 minutes, the resultant was dried with a reduced pressure drier equipped with a trap at 1 mmHg at 70 ° C. for 7 hours to remove methanol (the obtained carbon black is abbreviated as CB-X3).

A slurry was prepared by mixing 500 g of carbon black CB-A containing a zirconate coupling agent and 1 L of methanol at 6000 rpm for 30 minutes using a homomixer. On the other hand, 45 g of ZR-181 manufactured by Nippon Soda Co., Ltd. was dissolved in 150 mL of methanol to prepare a ZR-181 solution. The above slurry was transferred to a container equipped with a screw type stirrer, and the above ZR-181 was stirred under a stirring condition of about 1000 rpm.
The solution was added in small portions. After stirring for about 15 minutes, the resultant was dried with a reduced pressure drier equipped with a trap at 1 mmHg at 70 ° C. for 7 hours to remove methanol (the obtained carbon black is abbreviated as CB-X4).

(Synthetic resin) PC (polycarbonate) Iupilon E2000 manufactured by Mitsubishi Engineering-Plastics Co., Ltd. PBT (polybutylene terephthalate) Novadur 5040ZS manufactured by Mitsubishi Engineering-Plastics Corporation ETFE (ethylene tetrafluoroethylene copolymer) Asahi Glass Co., Ltd. Aflon COP C55AP

(Heat Stabilizer) PEPQ (manufactured by Clariant Japan Co., Ltd.) (Method of manufacturing seamless belt) A blend of thermoplastic resin and carbon black shown in Tables 1 and 2, and a twin-screw kneading extruder (manufactured by Ikekai Kihan Co., Ltd.) The mixture was kneaded into pellets by PCM45).

[0110] The obtained pellets were prepared with a circular die having a diameter of 40.
The extruder was extruded below the annular die in the form of a molten tube using an extruder of mm.

The extruded molten tube was brought into contact with the outer surface of a cooling mandrel mounted on a coaxial axis via a support rod on the same axis as the annular die, and was cooled and solidified to obtain a seamless belt.

(Evaluation) The evaluation was performed by cutting the seamless belt into a required size as needed.・ Surface resistivity Ω The surface resistivity can be suitably measured depending on the measuring instrument.

As a sample having a surface resistivity of 1 to 1 × 10 ⁶ Ω, Loresta manufactured by Dia Instruments Co., Ltd. was used.

As a sample having a surface resistivity of 10 ⁶ to 1 × 10 ¹³ Ω, Hiresta manufactured by Diamond Instruments Co., Ltd. was used.

As a sample having a surface resistivity of 10 ¹³ to 1 × 10 ¹⁶ Ω, a microcurrent measuring device R8340A manufactured by Advantest Corporation was used.

The measurement time was set to 10 seconds, and measurements were made at 40 locations per seamless belt to obtain the geometric mean of the maximum, minimum, and all measured values.

Appearance The appearance of the obtained seamless belt was visually evaluated for the presence or absence of foaming flaws caused by resin deterioration.

(Example 1) A seamless belt made of PC / CB-X1.

A good sample was obtained without appearance defects such as foaming scratches due to resin deterioration.

The surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

Comparative Example 1 A seamless belt made of PC / CB-A manufactured by the same method as in Example 1 except that the carbon type was changed.

This seamless belt was found to have poor appearance such as foaming flaws, which are considered to be caused by resin deterioration. The surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

However, when this seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed, an image defect corresponding to foaming flaw occurred when a solid image was output.

(Example 2) PBT / PC manufactured by the same method as in Example 1 except that the blending of the thermoplastic resin was changed.
/ CB-X1.

The seamless belt was good in appearance without defects such as foaming scratches due to resin deterioration. Further, the surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

(Comparative Example 2) A PBT / PC / CB- produced by the same method as in Example 2 except that the carbon type was changed.
A is a seamless belt.

This seamless belt was confirmed to have poor appearance such as foaming flaws, which are considered to be caused by resin deterioration.

The surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

However, when this seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed, an image defect corresponding to foaming flaw occurred when a solid image was output.

(Example 3) PBT / P produced by the same method as in Example 2 except that the carbon black concentration was changed.
It is a seamless belt made of C / CB-X1.

This seamless belt was excellent without any appearance defects such as foaming scratches due to resin deterioration. The surface resistivity was about 10 ¹² Ω, which was a level suitable for a transfer belt.

This seamless belt was mounted on an image forming apparatus as a transfer belt, and the image was evaluated. A good image was obtained.

(Comparative Example 3) PBT / P produced by the same method as in Comparative Example 2 except that the carbon black concentration was changed.
It is a seamless belt made of C / CB-A.

As in Comparative Example 2, poor appearance such as foaming scratches, which could be caused by resin deterioration, was confirmed.
It was lighter than the seamless belt. It is considered that the degree of resin deterioration was reduced by the lower concentration of CB-A which causes resin deterioration.

Example 4 A PBT produced by the same method as in Examples 2 and 3 except that the carbon black concentration was changed.
/ PC / CB-X1.

This seamless belt was good without any appearance defects such as foaming scratches due to resin deterioration. Further, the surface resistivity was about 10 ⁴ Ω, which was a level suitable for a photoreceptor transfer belt.

A charge transport layer is provided on the outer layer of the seamless belt,
A charge generating layer was formed, and was mounted on an image forming apparatus as a photoreceptor belt, and image evaluation was performed. As a result, a good image was obtained.

(Comparative Example 4) A PBT produced by the same method as in Comparative Examples 2 and 3 except that the carbon black concentration was changed.
/ PC / CB-A is a seamless belt.

In this seamless belt, defective appearance such as foaming scratches, which is considered to be caused by resin deterioration similar to Comparative Examples 2 and 3, occurred more frequently than the seamless belts of Comparative Examples 2 and 3. It is considered that the degree of resin deterioration was increased by an increase in the concentration of CB-A which causes resin deterioration.

(Example 5) ETFE manufactured by the same method as in Examples 1 and 2 except that the blending of the thermoplastic resin was changed.
/ CB-X1.

This seamless belt was good without any poor appearance such as foaming scratches due to resin deterioration. Further, the surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The present seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

(Comparative Example 5) ETFE manufactured by the same method as Comparative Examples 1 and 2 except that the blending of the thermoplastic resin was changed.
/ CB-A is a seamless belt.

In the seamless belt, defective appearance such as foaming scratches, which is considered to be caused by resin deterioration similar to Comparative Examples 1 and 2, occurred more than the seamless belts of Comparative Examples 1 and 2.

ETFE has a high melting point of 265 ° C. and requires a temperature of about 300 to 330 ° C. when forming a seamless belt. Therefore, ETFE has a higher temperature than a seamless belt made of PBT / PC formed at a processing temperature of about 260 to 280 ° C. It is considered that the degree of resin degradation during melt processing also became more severe.

Example 6 A seamless belt made of PBT / PC / CB-A / alkylsilane was used.

Instead of treating CB-A with alkylsilane in advance, alkyl silane was added together with PBT, PC and CB-A during kneading.

By increasing the amount of alkylsilane relative to CB-A in this seamless belt as compared with Example 2, it was possible to suppress appearance defects due to foaming and the like even without prior treatment. The surface resistivity is 10 ⁸ Ω
The degree and the level suitable for the intermediate transfer belt were obtained.

The present seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

(Example 7) A seamless belt made of PBT / PC / CB-X2.

A carbon black was prepared in the same manner as in Example 2 except that CB-X2 obtained by treating CB-A with an aluminate-based coupling agent was used.

The seamless belt was good in appearance without defects such as foaming scratches due to resin deterioration. Further, the surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The present seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and an image evaluation was performed. As a result, a good image was obtained.

(Example 8) A seamless belt made of PBT / PC / CB-X3.

A carbon black was prepared in the same manner as in Example 2 except that CB-X3 obtained by treating CB-A with a titanate coupling agent was used.

This seamless belt was good in appearance without any defective appearance such as foaming scratches caused by resin deterioration. Further, the surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

(Example 9) A seamless belt made of PBT / PC / CB-X4.

A carbon black was prepared in the same manner as in Example 2 except that CB-X4 obtained by treating CB-A with a zirconate coupling agent was used.

The seamless belt was good in appearance without defects such as foaming scratches due to resin deterioration. Further, the surface resistivity was about 10 ⁸ Ω, which was a level suitable for an intermediate transfer belt.

The present seamless belt was mounted on an image forming apparatus as an intermediate transfer belt, and image evaluation was performed. As a result, a good image was obtained.

The evaluation results of the examples and comparative examples are shown in Tables 1 and 2.

[0165]

[Table 1]

[0166]

[Table 2]

[0167]

As is clear from the above Examples and Comparative Examples, according to the present invention, since deterioration of the resin is suppressed, the appearance is good without foaming flaws and the like, and the mechanical properties are deteriorated due to the deterioration of the resin. The present invention provides a seamless belt containing no carbon black, a belt for an image forming apparatus using the seamless belt, and an image forming apparatus using the belt for the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a side view of a conventional intermediate transfer device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charger 3 Exposure optical system 4 Developing device 5 Cleaner 6 Conductive seamless belt 7, 8, 9 Transport roller

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) C08K 5/541 C08L 67/00 C08L 67/00 101/00 101/00 101/12 101/12 G03G 5/10 A G03G 5/10 21/00 350 21/00 350 C08K 5/54 (72) Inventor Makoto Morikoshi 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation Yokkaichi Office (72) Inventor Norihiro Otsu Yokkaichi, Mie Prefecture 1 Tohocho Mitsubishi Chemical Corporation Yokkaichi Office F-term (reference) 2H032 AA05 BA09 2H035 CA05 CB06 2H068 AA52 AA55 AA58 BA58 BB23 BB24 BB25 BB55 CA02 4J002 AA001 AA011 AA021 AC031 AC061 BB131 BD121 BD1211 BG031 BG041 BP011 BP021 CB001 CC031 CC181 CD001 CF001 CF051 CF061 CF071 CF081 CF101 CF161 CF211 CG001 CH091 CK021 CL001 CL071 CM031 CM041 CN011 CN031 DA037 EC076 EG046 EX026 EX036 FD146 GM01

Claims (17)

[Claims] At least one coupling agent selected from the group consisting of a silane coupling agent, an aluminate coupling agent, a titanate coupling agent and a zirconate coupling agent, carbon black, and a synthetic resin A seamless belt comprising a composition comprising: 2. A seamless belt comprising a composition containing carbon black containing a coupling agent and a synthetic resin. 3. The seamless belt according to claim 2, wherein the coupling agent and the carbon black have a chemical bond. 4. The seamless belt according to claim 1, wherein the coupling agent contains fluorine. 5. The carbon black has a specific surface area of 50 to 50.
Seamless belt according to any one of claims 1 to 4, characterized in that 500m is 2 / ^g. 6. The seamless belt according to claim 1, wherein the content of the coupling agent is 0.001 to 100 mmol per 1 g of carbon black. 7. The seamless belt according to claim 1, wherein the coupling agent is a silane coupling agent. 8. The seamless belt according to claim 1, wherein the content of carbon black in the composition is 3 to 30% by weight. 9. The seamless belt according to claim 1, wherein the synthetic resin is a thermoplastic resin. 10. The thermoplastic resin having a Tm (melting point) of 18
The seamless belt according to claim 9, wherein the temperature is 0 ° C. or higher. 11. The seamless belt according to claim 9, wherein the thermoplastic resin has a Tg (glass transition temperature) of 100 ° C. or higher. 12. The seamless belt according to claim 9, wherein the thermoplastic resin is polyester. 13. The seamless belt according to claim 9, wherein said thermoplastic resin is polycarbonate and / or alkylene terephthalate. 14. seamless belt according to any one of claims 1 to 13, the surface resistivity is characterized by a ¹⁰ 0 ^{~10 16 Ω.} In 15. The surface resistivity of ¹⁰ 0 ^{~10 16 Ω,}
The seamless belt according to claim 14, wherein the maximum value / minimum value in one belt is 100 or less. 16. A belt for an image forming apparatus, which is an intermediate transfer belt for an image forming apparatus, a transfer belt, or a photosensitive belt, comprising the seamless belt according to any one of claims 1 to 15. 17. An image forming apparatus comprising the belt for an image forming apparatus according to claim 16.