JP2002214923A - Endless belt for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless belt for an image forming device excellent in the total balance of mechanical strength, dimensional accuracy, resistance control, flame retardant property, appearance and processing property. SOLUTION: The endless belt for an image forming device contains polyallylate (component A) and carbon black having <1% volatile content (component B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoreceptor device, an intermediate transfer device, a paper transport transfer device, a transfer separation device, a charging device, a developing device, a transfer device and the like incorporated in an electrophotographic copying machine and a laser printer. The present invention relates to an endless belt for an image forming apparatus suitable for use. The endless belt of the present invention has mechanical strength, dimensional accuracy, resistance value control, flame retardancy,
Excellent balance of overall appearance and workability.

[0002]

2. Description of the Related Art Conventionally, a seamless belt (endless belt) is frequently used in an intermediate transfer device, a transfer separation device, a charging device and the like of an electrophotographic copying machine and the like.
FIG. 1 is a side view of a conventional intermediate transfer device. In the figure, 1 is a photosensitive drum, and 6 is an endless belt for an image forming apparatus. 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 provided around the photosensitive drum 1. Are located.

[0003] The conductive seamless belt 6 is stretched over conveying rollers 7, 8, and 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, the surface of the photosensitive drum 1 rotating in the direction of arrow A 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 transferred to the recording paper 11 between the transport roller 9 and the pressing roller 12.

A color electrophotographic apparatus having an image forming apparatus using the above-mentioned intermediate transfer belt is attached or attached to a transfer drum, which is a conventional technique, and transfers an image from a first image carrier to the transfer drum. Compared with a color electrophotographic apparatus having an image forming apparatus, for example, a transfer apparatus as described in Japanese Patent Application Laid-Open No. 63-301960, processing and control of a transfer material as a second image carrier (for example, The image can be transferred from the intermediate transfer belt without the need for gripping, adsorbing, giving a curvature to the gripper, etc., so that 40 g of envelopes, postcards, label paper, etc.
/ From m ² approximately thin paper up to 200 g / m ² approximately thick paper has the advantage of wide or narrow or wide, can be transferred irrespective of the length of length.

The above is an outline of an image forming apparatus using an intermediate transfer belt. The above-described intermediate transfer belt and transfer / transport belt (hereinafter, the intermediate transfer belt and the transfer / transport belt are collectively referred to as a belt-shaped transfer member). ) Is an important part that determines the image quality, durability, and cost of the image forming apparatus. Therefore, with the spread of full-color electrophotographic apparatuses, higher-function, lower-cost belt-shaped transfer members are required. It has become to.

On the other hand, the following proposals have been made from the viewpoint of the material of the belt-shaped transfer member. (1) A method using a fluorine-based material. For example, Japanese Patent Application Laid-Open
No. 40417, JP-A-7-92825, JP-A-8-267605, and the like disclose an intermediate transfer member using a fluorine-based resin, elastomer, or rubber.

(2) A method using an olefin material. For example, JP-A-5-31016, JP-A-7-24
No. 912 discloses a film using an olefin-based material. (3) A method using polycarbonate or polyalkylene terephthalate. For example, JP-A-3-89375, JP-A-4-313775, JP-A-6-149
No. 081, for example.

(4) A method using polyarylate. For example, JP-A-2000-137389. The following proposals have been made from the viewpoint of the manufacturing method. (1) A method of dissolving a resin using a solvent, evaporating the solvent after forming a film. For example, Japanese Patent Application Laid-Open No. 5-77252 discloses a method for manufacturing a seamless belt by centrifugal molding. Further, Japanese Patent Application Laid-Open No. 9-269674 discloses a method of obtaining a seamless belt by performing multilayer coating on a cylindrical substrate and finally removing the cylindrical substrate.

(2) A method of heating and melting a thermoplastic resin and extruding the same using an extruder. For example, JP-A-3-89
No. 357, Japanese Patent Application Laid-Open No. 5-345368, and the like disclose a method of manufacturing a semiconductive belt (seamless belt) by extrusion molding. As described above, the belt-shaped transfer member is required to have higher performance and lower cost. This will be described in detail below.

(A) Excellent creep resistance (B) High toughness, not easily cracked or cracked (C) High yield elongation and excellent spring recovery ( D) Small dimensional change due to use environment (temperature / humidity) (E) Excellent flame retardancy (F) Low cost (G) Surface free of bumps and scratches, smooth and appearance In view of such demands, a look at the above-described prior art reveals that a material or a manufacturing method that satisfies all of the above requirements A to G has not yet been proposed.

That is, first, the fluorine-based resin is
Does not meet the conditions. In other words, due to poor creep resistance, the belt tension decreases during repeated use, and color misregistration (due to misregistration of the transfer position between colors when multiple colors of toner are transferred in a superimposed manner). Toner does not overlap), or eventually, a slip occurs with the drive roller, and the drive becomes impossible. Further, the fluorine-based material has a high molding temperature, is difficult to mold, and has a high raw material cost, so that the above condition F is not satisfied.

On the other hand, an olefin-based material satisfies the above condition F, but has the same A property as a fluorine-based material.
Does not meet the conditions. Further, the olefin-based material does not satisfy the above condition E. On the other hand, polyesters such as polycarbonate and polyalkylene terephthalate (for example, polyethylene terephthalate and polybutylene terephthalate) satisfy all the above items A to G to some extent and are excellent materials. But,
Polycarbonate and polyalkylene terephthalate are
Since the weather resistance is insufficient, there is a possibility that deterioration due to ozone or ultraviolet rays generated by a discharge at the time of application of a transfer bias or the like occurs, the brittle material is repeatedly used, and eventually cracks or cracks are generated.

That is, although polycarbonate and polyalkylene terephthalate can satisfy the items A to G in a good balance at the beginning, the mechanical characteristics are deteriorated by repeated use, and the item B cannot be satisfied. There was a problem. In addition, there is also a problem that the molecular weight tends to decrease particularly due to repeated use, and the item B cannot be satisfied. The reason why the molecular weight of polycarbonate or polyalkylene terephthalate is reduced by repeated use is presumed to be that hydrolysis is promoted by nitric acid generated as a result of discharge such as transfer bias.

Further, it has been proposed that polyarylate can satisfy A to F in a well-balanced manner. However, when polyarylate and carbon black are heated and melted by an extruder or the like, scratches due to foaming on the surface of the molded body are generated. When this is used as an intermediate transfer belt, there has been a problem that an image defect corresponding to a foaming flaw occurs in an output image, so that it has not been put to practical use until now. That is, G could not be satisfied.

Next, a molding method will be described. The method of molding using a solvent described above can be applied only to (1) a resin soluble in a solvent. (2) The drying (removal of the solvent) step is essential, and the production requires a lot of time and energy. (3) It is difficult to improve mechanical properties by resin orientation (stretching). (4) A large amount of a solvent (particularly an organic solvent) is generated in the drying step, and there is a concern about the effect on the environment. There are problems such as.

On the other hand, the method in which the resin is heated and melted and extruded is the most efficient and preferable method for producing an endless belt-shaped transfer member while minimizing discharge. However, JP-A-3-89357 described above,
In JP-A-5-345368 and the like, the material is limited to polycarbonate and fluororesin, and therefore, an endless belt-shaped transfer member satisfying the above conditions A to G cannot be obtained.

As described above, the prior art has advantages and disadvantages, and an endless belt-shaped transfer member that satisfies all the conditions A to G even after repeated use has been desired.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to provide excellent creep resistance, high mechanical properties such as toughness and yield elongation,
An object of the present invention is to provide an endless belt for an image forming apparatus, which has a small dimensional change due to a use environment, has excellent flame retardancy, is low in cost, and has a good appearance.

[0020]

Means for Solving the Problems Therefore, the present inventors have found that the molding temperature of polyarylate is particularly high among general thermoplastic resins. Carbon black generally has many functional groups on its surface other than carbon skeleton. As a result of a thorough study, the main component of the generated gas was exposed to high temperatures in the appearance defect phenomenon caused by foaming on the surface of the endless belt made of polyarylate containing carbon black. Decomposition products of functional groups on carbon black surface due to high temperature.They are decomposed products of polyarylate generated by contact with functional groups on carbon black surface at high temperature, and select carbon black with particularly few functional groups on the surface. If it is blended with polyarylate, which requires a high temperature during processing, It found that almost no a degree, have reached the present invention.

That is, the gist of the present invention resides in (1) an endless belt for an image forming apparatus, which comprises at least the following components A and B. Component A: polyarylate Component B: carbon black having a volatile content of less than 1% The following embodiments are also included in the gist of the present invention. (2) The endless belt for an image forming apparatus according to the above (1), wherein the polyarylate of the component A is a polyarylate comprising bisphenol A and an aromatic dicarboxylic acid. (3) The weight ratio of each component is as follows: component B / component A = 3/97
The endless belt for an image forming apparatus according to the above (1) or (2), wherein the thickness is 30 to 70/70. (4) The specific volume resistivity is in the range of 1 to 10 ¹⁵ Ω · cm, and the maximum value of the specific volume resistivity in one belt /
(1) wherein the minimum value is 1 to 100.
The endless belt for an image forming apparatus according to any one of (1) to (3). (5) An image forming apparatus comprising the endless belt for an image forming apparatus according to any one of (1) to (4).

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Component A: Polyarylate In the present invention, the polyarylate resin is a general term for compounds represented by the following structural formula (1).

[0023]

Embedded image

(Wherein, R ¹ and R ² are an optionally substituted bivalent phenylene group or an arylene group of a naphthylene group. Examples of the substituent include a halogen atom such as a fluorine atom and a chlorine atom; An alkyl group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, or an alkylene group such as a 1,2-ethylene group and a 1,3-propylene group.) Further, a polyarylate resin was used. In this case, it was also found that there were the following advantages as compared with polycarbonate and polyalkylene terephthalate. (1) Even when exposed to a high temperature environment, creep is small. Therefore, when the image forming apparatus or the belt unit is transported (especially in a container), or when the temperature in the apparatus is increased when the image forming apparatus is used, the peripheral length of the belt is elongated and the belt is elongated. Thus, the tension applied between the rollers is reduced, and the belt is less likely to be slackened.

This advantage is greatest especially in an image forming apparatus of the simultaneous transfer fixing type (in an intermediate transfer belt type image forming apparatus, a secondary transfer and a fixing are simultaneously performed by using a heating member). The low creep of the polyarylate resin is considered to be due to the effect of the rigidity of the molecular chain due to the high density of the aromatic rings.

(2) High flame retardancy. For example, when compared with the limiting oxygen index (LOI), the L of the polyarylate resin
The OI is 36.8, the LOI of the polycarbonate resin is 24.9, and the LOI of the polyethylene terephthalate resin is 26.3, which clearly shows the superiority of the polyarylate resin. It is considered that the difference in flame retardancy is also due to the difference in density of aromatic rings. The high flame retardancy is very preferable from the viewpoint of the safety of the endless belt-shaped transfer member to which a high voltage (about 100 V to several kV) is applied.

In the present invention, the polyarylate resin is a general term for the compound represented by the structural formula (1). For example, specific examples of the polyarylate resin studied in the course of reaching the present invention include the following structural formula Examples of the compounds (2) to (4) include, but are not limited to, the following.

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

Of these, from the viewpoint of ease of synthesis (ease of obtaining raw materials) and toughness, the structural formula (2)
The compound represented by is preferred. Polyarylate has a large number of aromatic rings in the structural unit, so that the weather resistance and heat resistance of the resin are improved as compared to, for example, resins such as polycarbonate and polyalkylene terephthalate. The temperature required for molding increases.

For example, polybutylene terephthalate (PBT), which is a typical example of polycarbonate and polyalkylene terephthalate, and typical optimum processing temperatures of polyarylate are as follows. Polycarbonate: 260-300 ° C PBT; 230-250 ° C Polyarylate: 300-360 ° C (Source: Comparison list of physical properties between Iupilone and other resins in “Polycarbonate Iupilon Catalog” of Mitsubishi Engineering-Plastics Corporation) In order to mold a polyarylate resin, for example, a U polymer (product name) manufactured by Unitika Ltd. corresponding to the above structural formula (4) as a commercially available polyarylate; A film having a good appearance can be obtained even when processed at a temperature. However, in order to use it as an endless belt, it is kneaded with carbon black for the purpose of imparting conductivity to obtain pellets. If you try to obtain a film by molding at ℃, scratches due to foaming on the film surface It will form, it is impossible to obtain a good film.

When the molding temperature is set low or the residence time in the molding machine is shortened, foaming is reduced. However, when the molding temperature is lowered, melt fracture is likely to occur, and appearance defects different from foaming occur. However, when the resin temperature is low, the viscosity becomes high, so that there is a problem that the extruder cannot be satisfactorily extruded unless the extruder has a high capacity. Ingredient B: carbon black In the present invention, carbon black is blended for imparting conductivity in order to form an endless belt for an image forming apparatus.

However, in general, a molded product obtained by melt processing a material obtained by combining polyarylate and carbon black is accompanied by deterioration such as foaming as described above. In the present invention, by limiting the carbon black to be combined, the general molding processing temperature of polyarylate is 300 to 3
Even if processing is performed at about 60 ° C., problems due to foaming can be significantly suppressed.

Functional group of carbon black Carbon black generally has a functional group such as a hydroxyl group, an amino group and a carboxylic acid on the surface. When carbon black and a resin are blended, this functional group exhibits an affinity between the resin and the resin, and the carbon black is well dispersed in the resin. , Amino groups, carboxylic acids, and the like generate decomposition gases as water, ammonia, carbonic acid, and the like, respectively.
In particular, decomposition starts remarkably at about 300 ° C. "The functional groups on the surface of carbon black are likely to become radical generators due to the effect of π electrons on the structure of the carbon black used as the base material. Are liable to decompose and deteriorate. "

The amount of the functional group on the surface of carbon black can be regarded as a volatile component.
It can be quantified by the volatile content identification method of 6221. Briefly, Xg of carbon black is weighed and steamed according to JIS K6221. If the residue (residue) is Yg, the volatile content is Δ (XY).
It is calculated by × 100 ° / X.

In the present invention, if the volatile content is less than 1% by weight (based on the weight of carbon black), the functional groups on the surface of the carbon black can be obtained even when the temperature reaches about 300 to 360 ° C., which is the molding temperature of polyarylate. Because the absolute amount is small,
Since the absolute amount of the decomposition gas is small and the amount in contact with the resin is also small, the deterioration of the resin is also small, and as a result, an endless belt free from defects such as foaming even when blended with polyarylate and melt-processed is obtained be able to.

Further, when the volatile matter content is 0.5% by weight or less, the deterioration is further reduced, so that it is more preferable. When the volatile matter content is 0.3% by weight or less, the deterioration phenomenon due to the functional group is substantially suppressed. Particularly preferred. This makes it possible to obtain an endless belt for an image forming apparatus by imparting conductivity while utilizing the characteristics of polyarylate as a resin.

The physical properties of the carbon black other than the functional groups are not particularly limited in the present invention, but preferred examples are listed below. -Type 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, and furnace black. These can be used alone or in combination.

Specific surface area The carbon black used in the present invention is intended to exhibit conductivity. In general, it is said that the larger the specific surface area of carbon black, the lower the powder resistance and the easier it is to develop conductivity. Therefore, the larger the specific surface area is, the more preferable it is to develop conductivity by adding a small amount of carbon black.

Specifically, the specific surface area as measured by the BET method is preferably at least 10 m ² / g, more preferably at least 50 m ² / g. On the other hand, if the specific surface area is too large,
Poor dispersion of carbon black in resin occurs,
There is a problem that a decomposition reaction of the resin due to the catalytic action of the carbon black occurs due to an increase in the contact area with the resin per unit weight of the carbon black.
Preferably 1000 m ² / g or less specifically, 500 meters ²
/ Is particularly preferred.

The specific surface area is measured according to ASTM D3037. -Particle size The particle size of the carbon black (which means the primary particle size, not the diameter of the structure formed by collecting the particles) is not particularly limited, but carbon black having a small particle size generally has a specific surface area. Since the particle size is large, the conductivity is high, and the decomposition reaction of the resin is easily caused, the particle size of 15 to 40 nm can be exemplified as a range in which the effects of the present invention can be most effectively exhibited.

The primary particle size is determined by observing the particle size with an electron microscope, and depending on the case, refers to the arithmetic average of 10 or more measured values. -DBP oil absorption The DBP oil absorption is not particularly limited, but the carbon black used in the present invention is intended to exhibit conductivity.
In general, the larger the DBP oil absorption, the lower the powder resistance and the higher the conductivity of carbon black. Therefore, the larger the DBP oil absorption, the more preferable it is to exhibit conductivity by adding a small amount of carbon black.

Specifically, according to JIS K6221, 35
It is preferably at least mL / 100 g, more preferably at least 45 mL / 100 g. In addition, carbon black having an excessively large DBP oil absorption may empirically cause poor dispersion in the resin. Therefore, it is preferable that carbon black is somewhat smaller, specifically, 500 mL / 100 g or less.
More preferably 300 mL / 100 g or less, 2
It is particularly preferred that the amount be not more than 00 mL / 100 g.

Examples of carbon black products SCF # 4000 and SCF # 401 manufactured by Mitsubishi Chemical Corporation as carbon blacks satisfying these physical properties.
0, # 4350 (trade name), Denka Black (trade name) manufactured by Denki Kagaku KK, and the like. -Additional compounding materials; optional components In the present invention, optional compounding components can be added according to various purposes.

Specifically, as additives, for example, phenolic antioxidants such as Irganox 1010 (trade name), phosphorus antioxidants such as Irgafos 168 (trade name) and PEPQ (trade name), sulfur-based oxidants Antioxidants such as antioxidants, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antifogging agents, antiblocking agents, slip agents, various organic and inorganic pigments, crosslinking agents, crosslinking assistants And various additives such as a coloring agent, a foaming agent, a dispersant, a copper damage inhibitor, an antistatic agent, and a flowability improver.

Examples of the various fillers include 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, carbon fiber, aluminum fiber, styrene steel fiber, brass Fiber, aluminum powder, wood powder, rice husk, metal powder, conductive metal oxide, organometallic compound, organometallic salt and the like can be mentioned.

Further, as far as the effects of the present invention are not significantly impaired, blending materials such as various thermoplastic resins and various elastomers can be blended as the second and third components. Additional component thermoplastic resins include 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 its hydrogenated derivative, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal,
Polyarylate, polycarbonate, polyimide, liquid crystalline polyester, polysulfone, polyphenylene sulfide, polybisamide triazole, polyetherimide, polyether ether ketone, acrylic, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, ethylene tetra Fluoroethylene copolymer, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkyl vinyl ether copolymer, alkyl acrylate copolymer,
Polyester ester copolymers, polyether ester copolymers, polyether amide copolymers, polyurethane copolymers, etc., or a mixture thereof can be used.

As the additional thermosetting resin, for example, one composed of one kind of epoxy resin, melamine resin, phenol resin, unsaturated polyester resin and the like or a mixture thereof can be used. ○ Compounding ratio of each component In the present invention, there is no limitation on the compounding ratio of each component, but as an example of a compounding ratio that effectively exerts an effect, conductivity may not be exhibited if the carbon black concentration is too low. Therefore, carbon black is preferably at least 3% by weight based on the total amount of polyarylate and carbon black,
It is more preferably at least 5% by weight, more preferably at least 10% by weight.

If the carbon black concentration is too high, the endless belt may become brittle. Therefore, the carbon black is preferably 30% by weight or less based on the total amount of polyarylate and carbon black, and if it is 20% by weight or less. More preferably, it is particularly preferably at most 15% by weight. However, in practice, it is necessary to set the resistance in combination with the degree of conductivity of carbon black so that a desired resistance level described later is obtained. -Physical properties required for endless belt for image forming apparatus In the present invention, a resin composition comprising each component is molded and used as an endless belt for an image forming apparatus.

Further, the endless belt aimed at by the present invention may be formed into a flat film once and then joined into a tubular shape later. Alternatively, the endless belt may be formed into a seamless tube shape from the beginning and then cut into a ring. Although it may be formed as a seamless belt, it is more preferable to form a seamless belt without a seam because the seam does not affect an image when used in an image forming apparatus.

The endless belt for an image forming apparatus is, for example, an intermediate transfer belt, a transfer belt, a photosensitive belt,
For example, a toner jet belt can be used.
Physical properties required for the endless belt for an image forming apparatus include a resistance value, a film thickness and the like. -Resistance value Since the endless belt of the present invention is assumed to be used for an image forming apparatus, it needs to have a certain degree of conductivity.

The conductivity is exhibited by the proper amount of carbon black, and the conductivity can be quantitatively evaluated by, for example, measuring the volume resistivity. The following devices can be exemplified as suitable measuring devices. Resistance meter: Ultra-high resistance meter R8340A (trade name) (manufactured by Advantest Co., Ltd.) Electrode: ultra-high resistance measurement sample box TR42 (trade name) (manufactured by Advantest Co., Ltd.) Specific resistivity is 1 to 10 ¹⁵
The resistance is preferably in the range of Ω · cm, but the resistance suitable for use in the image forming apparatus is further subdivided.

When used for an endless belt for a photoreceptor substrate, an endless belt for fixing, and the like, the volume resistivity is particularly preferably from 1 to 10 ⁶ Ω · cm. When used for an endless belt for intermediate transfer, an endless tube for development, or an endless tube for charging, the volume resistivity is particularly preferably from 10 ⁷ to 10 ¹³ Ω · cm.

When used for an endless belt for conveyance transfer, it is particularly preferable that the volume resistivity is 10 ⁸ to 10 ¹⁵ Ω · cm. When the endless belt has a multilayer structure, it is desirable that any one or a plurality of layers correspond to these resistance regions in total. Each of the endless belts 1 in a preferable resistance region
The distribution of the resistance value in the book is preferably small, and the maximum value of the resistance value / the minimum value of the resistance value (ratio) in one belt is 1 to 1.
00 is preferable, and 1-10 is more preferable.・ Film thickness The thickness of the seamless belt is 50 μm or more and 1000 μm.
Or less, and more preferably 100 μm or more and 700 μm or less. When the thickness is less than 50 μm, the seamless belt is easily stretched, which may cause a problem such as uneven color of an image.

In addition, the withstand voltage is insufficient, and it becomes impossible to apply a voltage sufficient to impart a charge required for transfer. On the other hand, if the thickness exceeds 1000 μm, it becomes difficult to perform flexible deformation, so that a small-diameter roll cannot be driven at a uniform speed, 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. ○ Manufacturing method of endless belt In general, extrusion molding method is adopted.

In the extrusion molding method, each component is kneaded using a conventional kneading machine such as a single screw extruder, a twin screw extruder, a Banbury mixer, a roll, a Brabender, a plastograph, a kneader and the like, and is once pelletized. After that, it is common to provide for extrusion molding, but in special cases, each component can be directly supplied to a molding machine and molded while kneading the present composition with a molding machine. The carbon black to be used has a small number of functional groups of less than 1% of volatile components, so that the dispersibility in the resin is poor, and an aggregate may be formed or the distribution of the resistance value may be deteriorated, so that the carbon black can be strongly dispersed. It is preferable to use a twin-screw kneading extruder. As for the kneading conditions, it is preferable to select conditions that allow sufficient dispersion, such as increasing the number of revolutions.

In kneading each component, all components may be kneaded at once, or some components may be kneaded first to form a master batch. Since it is often the purpose of producing a masterbatch to make the dispersibility uniform, it is preferable to knead the mixture under enhanced kneading conditions so as to disperse the aggregates.

The above pellets can be formed into a film by extrusion using a T-die molding machine or the like, cut into a required shape, and then spliced into a cylinder to obtain an endless belt. In the case of molding as a seamless belt, the pellet is formed into a cylindrical seamless tube using an annular die or the like, and then the seamless tube is cut into a ring shape to produce a seamless belt.

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. The belt diameter is 3
In the case of 0 mm or more, in the continuous melt extrusion molding method,
The inside diameter of the extruded tube can be controlled with high precision. The internal cooling mandrel method of the downward extrusion method which is not affected by gravity is preferable. When the diameter is less than 30 mm, in addition to the internal cooling mandrel method, the vacuum sizing method is used. Is preferred.

Since the extruded seamless belt must have necessary conductivity, uniform thickness, and mechanical strength, it is preferable that the extruded seamless belt be drawn in a non-stretched state (a state in which substantially no stretch is applied). . 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.

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 employ a method of cutting the seamless tube accurately along the circumferential direction by applying a blade, but other methods may be used.

[0063]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto. Example 1 Each component was blended at a ratio shown in Table 1 and pelletized with a vent type twin screw kneading extruder PMT32 (trade name) (manufactured by IKG Corporation). The rotation speed was 250 rpm. The kneading temperature was set at 340 ° C.

After the obtained pellets were dried at 130 ° C. for 8 hours, the inner diameter of the annular slit was 180 mm, and the lip width was 1 mm.
And extruded in a molten tube state below the annular die by using an extruder with an annular die of 40 mmφ. In all the examples and comparative examples, the resin temperature in the molding machine was adjusted so as to be within the range of 330 to 360 ° C. which is a general processing temperature of polyarylate resin.

The extruded molten tube was brought into contact with the outer surface of a cooling mandrel having an outer diameter of 170 mm mounted on the same axis as the annular die via a support rod and cooled and solidified to form a seamless endless belt. Next, the seamless belt was cut by a 340 mm length while being taken up by a core installed in the seamless belt and a roll installed outside while maintaining the cylindrical shape.

The endless belt of a seamless belt type having a diameter of about 169 mm was obtained by adjusting the residence time, the extrusion amount and the take-up speed so that the target thickness could be obtained. Film thickness is 1
The molding was performed while adjusting the distribution to be as uniform as possible. The performance was evaluated by various tests using the obtained seamless belt, and the results are shown in Table 1.

The molding materials used and the performance evaluation method are shown below. (A) Polyarylate (PAr) U Polymer U100 (trade name; manufactured by Unitika Ltd.) (Polyarylate resin comprising bisphenol A and aromatic dicarboxylic acid)

This corresponds to the resin of the structural formula (2) in the description. (B) Carbon black ・ Carbon black SFC # 4350 (trade name; manufactured by Mitsubishi Chemical Corporation)
Volatile content 0.3% Specific surface area 38m ² / g, Particle size 5
0nm, DBP oil absorption of 169cm ³ / 100g LFF MA100 (trade name, manufactured by Mitsubishi Chemical Co., Ltd.)
Volatile content 1.5% Specific surface area 110m ² / g, Particle size 2
4nm, DBP oil absorption of 100cm ³ / 100g LFF MA200RB (trade name, manufactured by Mitsubishi Chemical Co., Ltd.)
Volatile content 5.5% Specific surface area 78m ² / g, particle size 3
0 nm, measured in the circumferential direction 20mm pitch of the endless belt with a DBP oil absorption of 91cm ^3/100 g [Evaluation method] ○ Thickness Tokyo Seimitsu Co. Ikurometa. ○ Volume resistivity resistivity meter; Ultra high resistance meter R8340A (trade name) (manufactured by Advantest Co., Ltd.) Electrode; ultra-high resistance measurement sample box TR42 (trade name)
(Advantest Co., Ltd.) The applied voltage was 100 V, and the value 10 seconds after the application of the voltage was used as a representative value.

However, due to the measurable area of the measuring instrument, 1
Samples that cannot be measured at 00V (essentially 3 × 10 ⁷ Ω
cm or less) was measured with an applied voltage of 10 V.
Measure at 20mm pitch in the circumferential direction of the endless belt,
The maximum, minimum, and maximum / minimum values were obtained for each endless belt. Since the volatile matter of the carbon black used was low, no trouble such as foaming occurred on the surface of the molded product.

Since the volume resistivity is in the order of 10 ⁹ Ω · cm, it can be suitably used as an intermediate transfer belt. When this endless belt was mounted on an image forming apparatus and an image was output, a good image was obtained. Example 2 A volume specific resistivity of 1 was obtained by lowering the carbon concentration in the same manner as in Example 1 except that the mixing ratio was as shown in Table 1.
An endless belt in the order of 0 ¹¹ Ω · cm to 10 ¹² Ω · cm was obtained.

As in Example 1, no problem such as foaming occurred on the surface of the molded product. This can be suitably used as a transfer belt. When this endless belt was mounted on an image forming apparatus and an image was output, a good image was obtained. Example 3 Except that the compounding ratio shown in Table 1 was used, the volume specific resistivity was increased to 10 ⁶ Ω · by increasing the carbon concentration in the same manner as in Example 1.
An endless belt in the order of cm was obtained.

As in Example 1, no troubles such as foaming occurred on the surface of the molded product. This can be suitably used as a photoreceptor belt. When this endless belt was mounted on an image forming apparatus and an image was output, a good image was obtained. Comparative Example 1 In the same manner as in Example 1 except that the compounding ratio shown in Table 1 was used, polyarylate and carbon black (M
A100) was obtained.

Since the volatile matter of the carbon black used was high, a decomposition gas was generated during the molding at a molding temperature of 330 to 360 ° C., and foaming flaws were generated on the surface of the endless belt, resulting in poor appearance. Comparative Example 2 A polyarylate and a carbon black (M
A200RB).

Since the volatile matter of the carbon black used is higher than that of Comparative Example 1, a decomposition gas is generated during molding at a molding temperature of 330 to 360 ° C., and foaming flaws are generated on the surface of the endless belt. The appearance was worse than that of 1.

[0075]

[Table 1]

[0076]

According to the present invention, by selecting polyarylate as a base resin, it is excellent in creep resistance, toughness, flame retardancy and low cost, and when combined with a specific carbon black, polyarylate is used. The present invention can provide an endless belt for an image forming apparatus in which conductivity is imparted without causing deterioration such as foaming even when molding is performed at the molding processing temperature.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of an intermediate transfer device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charger 3 exposure optical system 4 developing device 5 cleaner 6 endless belt 7 transport roller 8 transport roller 9 transport roller 10 electrostatic transfer machine 11 recording paper 12 pressure roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03G 21/00 350 G03G 21/00 350 (72) Inventor Norihiro Otsu 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical F term in Yokkaichi Office (reference) 2H003 BB11 CC04 2H032 BA09 BA18 DA13 2H035 CA05 CB06 2H077 AD07 FA12 FA16 FA22 FA27 4J002 CF161 DA036 GM01

Claims (5)

[Claims] An endless belt for an image forming apparatus, comprising at least the following components A and B: Component A: polyarylate Component B: carbon black having a volatile content of less than 1% 2. The endless belt for an image forming apparatus according to claim 1, wherein the polyarylate of the component A is a polyarylate comprising bisphenol A and an aromatic dicarboxylic acid. 3. The weight ratio of each component is as follows: Component B / Component A = 3
The endless belt for an image forming apparatus according to claim 1, wherein the endless belt has a ratio of / 97 to 30/70. 4. A volume specific resistivity in a range of 1 to 10 ¹⁵ Ω · cm, and a maximum value / minimum value of a volume specific resistivity in one belt is 1 to 100. An endless belt for an image forming apparatus according to claim 1. 5. An image forming apparatus comprising the endless belt for an image forming apparatus according to claim 1.