JP2001034083A - Seamless belt, belt for image forming apparatus, and image forming apparatus - Google Patents

Abstract

[PROBLEMS] To provide a seamless belt having excellent bending resistance, a belt for an image forming apparatus using the seamless belt, and an image forming apparatus using the belt for the image forming apparatus. SOLUTION: The composition contains the following components A, B and C, the content of the component A is 1% by weight or more and less than 50% by weight, and the content of the component C is 3% by weight or more and less than 40% by weight. A seamless belt characterized by the following. Component A: a polyalkylene terephthalate having an MFR (unit: g / 10 min) of 0.4 or more and less than 9. Component B: Tensile modulus is 15000
Thermoplastic resin of kgf / cm ² or more. Component C: a conductive filler and / or a substance capable of imparting conductivity. However, the weight ratio A / B of the component A and the component B is 98/2 to 50/50, the MFR is based on JIS K-7210, and the temperature 2
It is a value measured at 60 ° C. under a load of 2.16 kgf.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a seamless belt excellent in physical properties such as moldability and bending resistance and an electrophotographic copying machine, a laser beam printer, a facsimile machine and the like using the seamless belt. The present invention relates to an image forming apparatus belt such as an intermediate transfer belt, a transfer belt, and a photoreceptor belt, and an image forming apparatus including the image forming apparatus belt.

[0002]

2. Description of the Related Art Conventionally, conductive seamless belts are frequently used in office automation equipment and the like. As the conductive seamless belt, a belt formed by mixing a conductive filler such as carbon black with a thermosetting resin or a thermoplastic resin is 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).

[0003] However, amorphous thermoplastic resins are superior in dimensional accuracy to thermoplastic crystalline resins, but are inferior in bending resistance. For example, when used for electrophotography as an intermediate transfer belt, cracks occur during use. Is easy to occur.

[0004] In order to solve this problem, there has been proposed a seamless belt in which a polycarbonate is mixed with a polyalkylene terephthalate such as polybutylene terephthalate (Japanese Patent Application Laid-Open No. 4-313775).

[0005]

However, polycarbonate (hereinafter, sometimes referred to as PC) and polyalkylene terephthalate (hereinafter, referred to as PA) such as polybutylene terephthalate (hereinafter, sometimes referred to as PBT) are used.
Sometimes called T. ) Is improved in bending resistance as compared with the seamless belt made of the polycarbonate described above, but the effect of the improvement is still insufficient. Further, since the polyalkylene terephthalate resin has high crystallinity, the dimensional accuracy of the seamless belt decreases when the blending amount is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a seamless belt having improved bending resistance without impairing the performance of a thermoplastic resin as a main component, a belt for an image forming apparatus having the seamless belt, and an image forming apparatus. Is to do.

[0007]

The seamless belt of the present invention comprises the following components A, B and C, and the content of the component C is 3% by weight or more and less than 40% by weight. .

Component A: MFR (unit: g / 10 min)
Component B: a thermoplastic resin having a tensile modulus of 15,000 kgf / cm ² or more Component C: a conductive filler and / or a substance capable of imparting conductivity.

However, the content (weight) of component A and component B
When the sum of (A + B) is 100, the ratio of A to (A + B) is 2 or more and less than 50, and the MFR is JIS.
According to K-7210, temperature 260 ° C, load 2.16
It is a value measured in kgf.

The inventors of the present invention have conducted intensive studies for the above-mentioned purpose. As a result, when a PAT having a tensile elastic modulus of 15,000 kgf / cm ² or more as a main component and a MFR value in a specific range is added, the main effect is as follows. The inventors have found that the flex resistance can be significantly improved without impairing the performance of the thermoplastic resin as a component, and have reached the present invention.

[0011]

Embodiments of the present invention will be described below. In the following (1) to (5), first, the resin composition forming the seamless belt of the present invention will be described. In (6), a method for forming a seamless belt will be described. In (7) to (8), the seamless belt will be described. The physical properties of the belt will be described.

(1) Component A: polyalkylene terephthalate (PAT) The type of PAT of the present invention is not particularly limited, and glycols constituting the alkylene component include ethylene glycol, triethylene glycol, 1,4-butanediol, and hexamethylene. Glycol, neopentyl glycol, 2,
An aliphatic dioxy compound such as 2,4,4-tetramethylene glycol can be selected.

More specifically, polybutylene terephthalate (PBT), polyethylene terephthalate (PET),
Polyethylene naphthalate (PEN) can be preferably used, and among them, PBT having particularly excellent bending resistance can be particularly preferably used. These may contain a third component as a copolymerization component.

In order to improve the number of times the seamless belt can be folded, the MFR (unit: g / 10 min) of PAT measured under a load condition of 260 ° C. and a load of 2.16 kg is 0.4 or more and less than 9, preferably 1 ~ 7, particularly preferably 2 ~
5

If the MFR of the PAT is 9 or more, draw-down may occur when forming a seamless belt by extrusion, and a good film may not be obtained. If the molding temperature is lowered, melt fracture may occur.

If the above MFR is less than 0.4, the viscosity is excessively high and melt fracture may occur.

The above MFR is 0.4 or more and less than 0.9 (g / g).
By using a PAT of 10 min), a seamless belt having excellent bending resistance can be obtained without drawdown even if the molding temperature is raised to a temperature at which no melt fracture occurs.

The PAT having this MFR value can be specifically obtained by increasing the molecular weight by strongly solid-phase polymerization. For example, PBT-Novadur 5040ZS (MFF manufactured by Mitsubishi Engineering-Plastics Corporation) can be obtained.
R: 4) and the like.

(2) Component B: Tensile modulus is 15000
kgf / cm ² thermoplastic resin.

Examples of the thermoplastic resin include polyamide, polyamide imide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystalline polyester,
One or two or more of polysulfone, polyethersulfone, polyphenylene sulfide, polybisamide triazole, polyetherimide and polyetheretherketone are listed, and particularly, polycarbonate (PC) and / or polyarylate (PAr), especially PC It is suitable.

The PC is preferably an aromatic polycarbonate. Aromatic polycarbonates are those in which at least a majority of the dihydroxy compounds to constitute the carbonate ester have two phenolic hydroxyl groups. Such dihydric phenols include bisphenols, especially bisphenol A. The aromatic polycarbonate is produced by reacting the above-mentioned dihydric phenol with a carbonate precursor such as phosgene, bischloroformate, or a carbonic acid diester.In the present invention, commercially available ones can be used. .

The MFR (unit: g / 10 min) of Component B measured at 260 ° C. and a load of 2.16 kg is not particularly limited, but is preferably 0.1 or more and less than 9.
It is particularly preferably from 0.2 to 6, and more preferably from 0.4 to 4.

If the component B has an MFR of 9 or more, drawdown may occur when a seamless belt is formed by extrusion, and a good film may not be obtained. In order to reduce the molding temperature, melt fracture may occur.

If the above MFR is less than 0.1, the viscosity is excessively high and melt fracture may occur.

The above MFR is 0.1 or more and less than 9 (g / 10
By using the component B as the main component, the seamless belt can be obtained with excellent bending resistance and without drawdown even when the molding temperature is raised to a temperature at which no melt fracture occurs.

The tensile modulus of these thermoplastic resins is usually about 15,000 to 30,000 kgf / cm ² .

(3) Component C: a conductive filler and / or a substance capable of imparting conductivity The conductive filler is not particularly limited as long as it satisfies the performance required for the intended use. it can.

Specifically, carbon fillers such as carbon black, carbon fiber, and graphite;
Metal-based conductive fillers, metal-oxide-based conductive fillers and the like can be used, and among them, carbon black is particularly preferred.

As the type of carbon black, acetylene black, furnace black, channel black, and the like can be preferably used. Among them, acetylene black, which has few functional groups as impurities and hardly causes poor appearance due to carbon aggregation, is particularly preferably used. it can. Further, the primary particle diameter is 10 to 100 nm, and the specific surface area is 10 to 2
Those having a water content of 00 m ² / g and a pH value of 6 to 11 are more preferred.

Examples of the substance capable of imparting conductivity include an ionic conductive substance such as a quaternary ammonium salt.

(4) Compounding Amounts of Components A, B, and C The molding material of the seamless belt of the present invention is mainly composed of component B (a thermoplastic resin having a tensile modulus of 15000 kgf / cm ² or more). is there.

When the total amount of components A, B and C is 100 parts by weight, the proportion of component B (thermoplastic resin) is 50-98.
It is preferably from 55 to 90% by weight, especially from 60 to 80% by weight. If this component B is less than 50% by weight, the dimensional accuracy of the seamless belt becomes poor,
If the amount is more than 98% by weight, the bending resistance of the seamless belt deteriorates.

The proportion of component A (PAT) is at least 1% by weight and
Less than 0% by weight, especially 5-40% by weight, especially 10-30%
% By weight. 1% by weight of component A
If it is less than 50%, the improvement of the bending resistance becomes insufficient, and 50%
With the above, the dimensional accuracy of the seamless belt deteriorates.

The ratio of the component C (conductive filler and the like) is 3 to
It is preferably 40 parts by weight, particularly preferably 5 to 35 parts by weight, particularly preferably 10 to 30 parts by weight. Components A and B are 2 /
98 ≦ A / B <50/50 is preferred, and 5/95 ≦ A /
More preferably, B ≦ 45/55 and 10/90 ≦ A / B ≦ 40/60.

If the amount of the component B is too small, the dimensional accuracy of the seamless belt deteriorates, and if the amount of the component A is too small, improvement in the bending resistance cannot be expected. If the amount of the component C is more than 40 parts by weight, the bending resistance of the seamless belt may be insufficient.

Although it is possible to develop conductivity with a very small amount of addition by using a conductive filler having a very high conductivity, if conductivity is developed with a very small amount of addition, resistance may be slightly increased due to poor dispersion. Since unevenness may occur in the distribution of values, it is preferable to express the desired conductivity at a somewhat high concentration, specifically, 3 parts by weight or more, more preferably 5 parts by weight or more, A content of 10 parts by weight or more is particularly preferable since conductivity can be stably exhibited.

(5) Additional Compounding Material (Optional Component) The compound for seamless belt molding of the present invention may contain any compounding component according to various purposes.

Specifically, antioxidants, heat stabilizers, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antifogging agents, antiblocking agents, slip agents, crosslinking agents, crosslinking aids Various additives such as an agent, a colorant, a flame retardant, and a dispersant can be added.

Further, various thermoplastic resins other than those described above, thermosetting resins, and the like, as long as the effects of the present invention are not significantly impaired.
Compounding materials such as various elastomers and various fillers can be compounded.

The thermoplastic resin as an optional component that can be added includes polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component, For example, ethylene / propylene copolymer rubber, styrene / butadiene rubber, styrene / butadiene / styrene / styrene block copolymer or a hydrogenated derivative thereof, polybutadiene, polyisobutylene, acryl, polyvinylidene fluoride, polyvinylidene fluoride, chlorotriene Fluoroethylene, ethylene tetrafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, alkyl acrylate copolymer, polyester ester copolymer, polyether ester Polymers, polyether amide copolymers, those composed of one or a mixture of these, such as polyurethane copolymers can be used.

Examples of the thermosetting resin include an epoxy resin, a melamine resin, a phenol resin, and an unsaturated polyester resin.

As the thermoplastic elastomer, those having a Young's modulus of 10,000 kgf / cm ² or less, preferably
A polymer of 100 to 5000 kgf / cm ² is used,
Polyester-based, polyamide-based, polyether-based, polyolefin-based, polyurethane-based thermoplastic elastomers and the like, and mixtures thereof can be used.

As the filler, for example, calcium carbonate (heavy or 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, carbon fiber, aluminum fiber, styrene steel fiber, brass fiber, aluminum powder, wood powder,
Rice hulls, graphite, metal powder, conductive metal oxides, organometallic compounds, organometallic salts and the like can be mentioned.

The blending amount of the thermoplastic resin is as described in A,
100 parts by weight or less, particularly preferably 50 parts by weight or less, based on 100 parts by weight of the total amount of the components B and C, and the compounding amount of the thermosetting resin is 100 parts by weight based on 100 parts by weight of the total amount of the above components A, B and C. The amount is preferably 50 parts by weight or less, and the blending amount of the elastomer is preferably 1 to 1 in total of the components A, B, and C.
The amount is preferably 100 parts by weight or less, particularly preferably 50 parts by weight or less with respect to 00 parts by weight, and the compounding amount of the filler is preferably 100 parts by weight or less, particularly 50 parts by weight or less with respect to 100 parts by weight of the total amount of the components A, B and C.

(6) Method for forming a seamless belt The above-mentioned composition, together with an optional component, if necessary, is usually kneaded with a single-screw extruder, twin-screw extruder, Banbury mixer, roll, Brabender, blast graph, kneader or the like. Can be kneaded.

Usually, each component is kneaded with a twin-screw kneading extruder or the like to form a pellet-shaped compound, which is then processed. In a special case, each component is directly supplied to a molding machine.
The composition can be molded while kneading the composition with a molding machine.

The seamless belt of the present invention is obtained by forming a seamless tube using the above-described composition, and cutting this into a ring shape. The method of forming the seamless tube is not particularly limited, and a known method such as a continuous melt extrusion method, a centrifugal molding method, a dipping molding method, an injection molding method, a blow molding method, or an inflation molding method is employed. Particularly preferred is the continuous melt extrusion molding method. 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 continuous melt extrusion molding, if the temperature of the molding die is too high, the viscosity of the resin becomes low, and it may not be possible to obtain a good seamless belt due to drawdown.

If the temperature of the molding die is lowered to a temperature close to the melting point of the resin, a part of the resin may be solidified or a melt fracture may occur, resulting in a slight roughness on the surface of the seamless belt. Higher is preferred.

When a seamless tube is manufactured by extrusion molding, an internal cooling mandrel method and an outsizing method have been proposed as methods for equalizing the internal stress.
In any case, during the period from the melt-extrusion to the cooling and solidification, a tension is applied in a specific direction and the molding is performed while being taken off. Therefore, the tension in a specific direction remains on the belt as residual stress, and even if the belt is apparently a perfect circle, if tension is applied by a roller, the belt will undulate due to the residual stress. Due to this undulation, the belt is likely to meander, and image deviation and cracks are easily generated.

On the other hand, by applying a pulling force to the melt-extruded seamless tube at three to eight locations in the circumferential direction or by pulling the seamless tube as close to a perfect circle as possible, the occurrence of the undulation can be prevented. become.

In particular, a core of a perfect circle is put in the take-up portion of the seamless tube, and a total of four units arranged at four equally spaced positions in the circumferential direction while passing the seamless tube outside the core and the core. The swelling can be sufficiently prevented by taking up with the belt type take-up machine.

When the diameter of the belt is 30 mm or more, the inner cooling mandrel system of the downward extrusion system, which is not affected by gravity, is capable of controlling the inner diameter of the extruded tube with high accuracy and can be controlled in the continuous melt extrusion molding method. When the diameter is less than 30 mm, a vacuum sizing method is preferable in addition to the internal cooling mandrel method.

The extruded seamless belt must have necessary conductivity, uniformity of thickness, and mechanical strength. Therefore, it is desirable that the extruded seamless belt be drawn in an unstretched state. This is because, although the mechanical strength can be expected to be improved by the stretching operation, problems such as a loss of uniformity of conductivity and a decrease in durability due to the tendency to tear in the stretching direction occur. Further, there is another problem that peeling occurs at the interface between the carbon black and the plastic, carbon is dropped, and uneven transfer occurs.

In the centrifugal molding method, generally, a resin in which a solution is dissolved is put into a cylindrical mold, and a temperature is applied while rotating the resin.
It consists of a step of taking out the seamless tube from the inside of the cylindrical mold after evaporating the solvent by half or more, and a step of fitting the seamless tube into the cylindrical mold and causing a thermosetting reaction by temperature.

In this centrifugal molding method, residual stress is less likely to remain than in extrusion molding. If the thermosetting reaction temperature and time are not sufficient, the belt-shaped resin is difficult to be transferred according to the shape of the cylindrical mold, so that the belt undulates when the tension is stretched by the rollers. By appropriately managing the temperature and time of the thermosetting reaction, undulation can be sufficiently prevented.

The dipping molding method is a method in which a cylindrical mold is immersed and applied in a resin dissolved in a solution, the solvent is volatilized, and then the seamless tube is pulled out from the mold. Otherwise, the belt-shaped resin is difficult to be transferred according to the shape of the cylindrical mold, so that the belt undulates when the tension is stretched by the roller. By appropriately managing the temperature and time, undulation can be sufficiently prevented.

To manufacture a seamless belt by cutting the formed seamless tube into a ring shape, a seamless tube having a required width is stretched between a pair of parallel rolls, and a cutter is attached to the seamless tube while rotating the roll. It is convenient to adopt a method of applying a blade and cutting the seamless tube exactly along its circumferential direction,
Other methods may be used.

(7) Physical Property of Seamless Belt Number of Folds When the seamless belt of the present invention is used in an image forming apparatus, for example, as an intermediate transfer belt, if the bending resistance is poor, cracks occur and images cannot be obtained. Preferably, the seamless belt has good bending resistance.

The degree of flex resistance is determined according to JIS P-8115.
Can be quantitatively evaluated by following the method for measuring the folding endurance of
It can be determined that a seamless belt having a large number of fold-resistant times is less likely to be cracked and has excellent bending resistance.

As a specific numerical value, if it is 500 times or more, it can be used as it functions as a seamless belt. However, practically, it is preferably 6000 times or more, and more preferably 8000 times or more. A number of 9000 or more is particularly preferable because cracks are less likely to occur.

Surface Resistivity The surface resistivity of the seamless belt used in the present invention is from 1 to
It is preferably 1 × 10 ¹⁶ Ω / □.

The more preferable range depends on the application. For example, when the belt is used as a photoreceptor belt, 1-1.times.1.times.
0 ⁹ Ω / □ and a low surface resistivity preferably charged when used as an intermediate transfer belt - 1 × that can be easily transcription
It is preferably 10 ⁶ to 1 × 10 ¹¹ Ω / □, and when used as a transporting transfer belt, a high region of 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □ which is easily charged and is not easily damaged even at a high voltage is preferred.

It is preferable that the distribution of the surface resistivity in one seamless belt is narrow. In each preferable surface resistivity region, the difference between the maximum value and the minimum value in one belt is one.
It is preferable that it is within the order of magnitude.

The surface resistivity of the film can be easily measured by, for example, an ultra-high resistance meter R8340A manufactured by Advantest Co., Ltd., Hiresta, Loresta (trade names) manufactured by Dia Instruments Co., Ltd.

Appearance When a seamless belt is used as an intermediate transfer belt or the like in an image forming apparatus, it is preferable that the surface is not smooth because image defects may occur if the surface is not smooth. It is preferable that there is no appearance defect due to such factors.

Young's Modulus When a seamless belt having a low Young's modulus is used in an image forming apparatus as an intermediate transfer belt or the like, an image defect may occur due to color misregistration caused by belt elongation caused by tension. Is preferably higher, specifically, more than 17,000 kgf / cm ² ,
More preferably, it is 000 kgf / cm ² .

Thickness of Seamless Belt The thickness of the seamless belt is preferably from 1 to 1000 μm, more preferably from 50 to 700 μm. When the thickness is less than 1 μm, the seamless belt is easily stretched, which causes a problem such as uneven color of an image. In addition, the withstand voltage is insufficient, and it becomes impossible to apply a voltage that is sufficient to provide the charge required for transfer.

If the thickness of the seamless belt exceeds 1000 μm, it becomes difficult to perform flexible deformation, so that it is not possible to drive at a uniform speed with a small-diameter roll, resulting in image transfer deviation. Furthermore, since the capacitance is small, it is not possible to apply the electric charge required for transfer unless a high voltage is applied, which not only increases the cost and size of the power supply device but also causes discharge between peripheral device parts. Problem arises.

The seamless belt may be used as it is, or may be wound around a drum or a roll.

Further, for the purpose of preventing meandering and reinforcing the end surface, a heat resistant tape is stuck around the inside and / or outside end of a seamless belt of 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.

[0072]

EXAMPLES The present invention will be described more specifically with reference to Examples 1 to 7 and Comparative Examples 1 to 6.

The conditions for manufacturing the material for the seamless belt in the following Examples and Comparative Examples are as follows. Note that M
FR conformed to JIS K-7210. Measurement temperature is 2
At 60 ° C., the measured load is 2.16 kg.

Materials The components were melt-kneaded using a twin-screw kneader at the blending amounts shown in Table 1 to obtain pellet-shaped resin compositions.

The following grades were used as raw materials.

<Component A: PAT> Component A-1: PBT; Nopadour 5040ZS; MF
R: 4 (g / 10 min) (Mitsubishi Engineering Plastics Co., Ltd.) Component A-2: PBT; Nopadour 5020; MFR:
12 (g / 10 min) (manufactured by Mitsubishi Engineering-Plastics Corporation) <Component B: PC or PAr> Component B-1: PC; Iupilon E-2000 (trade name); MFR: 2 (g / 10 min) (Mitsubishi Engineering Plastics Co., Ltd.), tensile modulus 2200
0 kgf / cm ² component B-2: PAr; U polymer U100 (trade name);
MFR: 1 (g / 10 min) (manufactured by Unitika Ltd.),
Tensile modulus 19000 kgf / cm ² <Component C: conductive filler> Carbon black; Denka black (manufactured by Denki Kagaku Kogyo Co., Ltd.) Kneading conditions Kneading machine PCM45 manufactured by Ikegai Kihan Co., Ltd. The material was extruded in the form of a molten tube below the annular die by an extruder having a diameter of 180 mm and a diameter of 40 mm to be cut into a circle having a length of 340 mm to obtain a resin-made conductive seamless belt having the thickness shown in each table.

The molding temperature was 230 ° C.

Evaluation The evaluation was performed by cutting the seamless belt into a required size as needed.

<Folding endurance> According to JIS P-8115 <Surface resistivity (Ω / □)> The surface resistivity can be measured by using a commercially available measuring instrument. I used them properly. Sample surface resistance is 10 ⁰ × 10 ⁶ Ω / □ was measured using a LORESTA. A sample having a surface resistance of 10 ⁶ × 10 ¹³ Ω / □ was measured using a Hiresta. Surface resistance is 10 ¹³
A sample having × 10 ¹⁷ Ω / □ was measured using R8340A. Loresta was manufactured by Dia Instruments Co., Ltd., and the electrode was an ASP terminal. Hiresta was also manufactured by Dia Instruments Co., Ltd., and the electrodes were HA terminals, and the applied voltage was 500 V. R8340A was manufactured by Advantest Corporation, the electrode was a JIS electrode, and the applied voltage was 500V. The measurement time was 10 seconds in each case.

Tables 1 and 2 show the measurement results of Examples 1 to 7 and Comparative Examples 1 to 6. Further, considerations of Examples 1 to 7 and Comparative Examples 1 to 6 are described after Tables 1 and 2.

[0081]

[Table 1]

[0082]

[Table 2]

<Consideration> According to Example 1, a seamless belt having excellent moldability, high folding endurance, high tensile modulus and good appearance was obtained. This seamless belt has a surface resistivity of 5.6E + 09 and can be suitably used for an intermediate transfer belt or the like.

In the first embodiment, the MFR of the PBT is 4. Comparative Example 2 described later is the same as Example 1 except that the MFR of the PBT is 12, but Example 1 has twice or more the number of times of folding endurance as compared with Comparative Example 2.

The second and third embodiments have a higher PBT ratio than the first embodiment. In Examples 2 and 3, the PBT
The same as Comparative Examples 3 and 4 except for the MFR of
Compared to Comparative Examples 3 and 4 using FR12 PBT, the number of times of folding is extremely large.

Example 4 is a seamless belt in which the surface resistivity is increased by lowering the carbon concentration than in Example 1. This seamless belt can be suitably used for an intermediate transfer belt, a transfer belt and the like.

Example 5 is a seamless belt in which the surface resistivity is increased by further lowering the carbon concentration than in Example 4. This seamless belt can be suitably used as a transfer belt.

Example 6 is a seamless belt in which the surface resistivity is lowered by increasing the carbon concentration as compared with Example 1. This seamless belt can be suitably used for a photoreceptor belt and the like.

Example 7 is a seamless belt using PAr as the thermoplastic resin of component B as the main component. This seamless belt is the same as Example 2 except that PAr was used instead of PC, and is a seamless belt having a good folding endurance like Example 2. In addition,
Comparative Example 6 is the same as Example 7 except that PBT having MFR12 was used, but Example 7 has a much larger number of folding endurance than Comparative Example 6.

Comparative Example 1 is a seamless belt in which the resin is made of only the above-mentioned PC. This seamless belt has a low folding endurance.

Comparative Example 2 is a seamless belt made of PC and PBT having MFR of 12. This seamless belt has a higher number of folding endurance than Comparative Example 1, but is considerably lower than that of Example 1.

Comparative Example 3 is a seamless belt in which the ratio of the PBT having an MFR of 12 is larger than that of Comparative Example 2. This seamless belt has a higher number of times of folding endurance than Comparative Examples 1 and 2, but is considerably lower than Example 2.

Comparative Example 4 is a seamless belt in which the ratio of the PBT having an MFR of 12 is further increased as compared with Comparative Example 3. Although the number of times of folding endurance is higher than Comparative Examples 1 to 3, it is considerably lower than that of Example 3.

Comparative Example 5 is a seamless belt composed of only PAr and carbon black. This seamless belt has a considerably low folding endurance.

In Comparative Example 6, a part of PAr in Comparative Example 5 was replaced with a PBT having an MFR of 12. Although the number of times of folding endurance is higher than that of Comparative Example 5, the number of times of endurance is significantly lower than that of Example 7, except that the MFR of 4 was used.

[0096]

According to the present invention, a seamless belt having excellent bending resistance can be obtained. This seamless belt has a good appearance and can be used favorably in an image forming apparatus or the like. According to the present invention, an image forming apparatus belt using such a seamless belt and an image forming apparatus using the image forming apparatus belt are provided.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Morikoshi 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation Yokkaichi Office (72) Inventor Norihiro Otsu 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation F-term in Yokkaichi Office (reference) 2H032 BA09 BA18 BA23 4F213 AA19 AA24 AA27 AA28 AA29 AA32 AA34 AA40 AB13 AE03 AG16 AH33 WA06 WA54 WA63 WB02 WC01

Claims (9)

[Claims] 1. A seamless belt comprising the following components A, B and C, wherein the content of component C is 3% by weight or more and less than 40% by weight. Component A: a polyalkylene terephthalate having an MFR (unit: g / 10 min) of 0.4 to less than 9 Component B: a thermoplastic resin having a tensile modulus of 15000 kgf / cm ² or more Component C: a conductive filler and / or a conductive material Substances that can be applied. However, the sum of the content (weight) of component A and component B (A +
Assuming that B) is 100, the ratio of A to (A + B) is 2 or more and less than 50, and the MFR is JIS K-721.
0, measured at a temperature of 260 ° C. and a load of 2.16 kgf. 2. The method according to claim 1, wherein the tensile modulus is 150.
A thermoplastic resin of at least 00 kgf / cm ² is polyamide,
Polyamide imide, polyacetal, polyarylate,
Polycarbonate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystalline polyester, polysulfone, polyethersulfone, polyphenylene sulfide, polybisamide triazole,
A seamless belt comprising one or more of polyetherimide and polyetheretherketone. 3. The method according to claim 2, wherein the tensile modulus is 150.
A seamless belt, characterized in that the thermoplastic resin of 00 kgf / cm ² or more is polycarbonate and / or polyarylate. 4. The seamless belt according to claim 1, wherein the polyalkylene terephthalate is polybutylene terephthalate. 5. The seamless belt according to claim 1, wherein the conductive filler or the substance capable of imparting conductivity is carbon black. 6. The seamless belt according to claim 1, wherein the surface resistivity is 1 × 10 ⁰ to 1 × 10 ¹⁶ Ω / □. 7. The seamless belt according to claim 1, which is formed by extrusion molding or injection molding. 8. 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 7. 9. An image forming apparatus comprising the belt for an image forming apparatus according to claim 8.