JP2006267626A - Endless belt for image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt for an image forming apparatus having satisfactory mechanical characteristics such as bending resistance, surface characteristics, and electrical characteristics, superior in toner transfer characteristics and toner cleaning characteristics, and coping with a high-quality image, and to provide an image forming apparatus including the endless belt for the image forming apparatus. <P>SOLUTION: The endless belt for the image forming apparatus has the main component of thermoplastic polymer component consisting of thermoplastic elastomer and/or thermoplastic resin. It includes ≥0.1 pts.wt. and <10 pts.wt. of an additional component having the melting point of ≥130°C and ≤260°C according to DSC measurement of the thermoplastic polymer component and the dropping point of ≥50°C and ≤200°C, on the basis of 100 pts.wt. of the thermoplastic polymer component. The additional component of low energy and low molecular weight having the prescribed dropping point adequately enhances dispersion effect for carbon black or the like when kneading the molding material. The surface of the endless belt is adequately subjected to bleeding out after the formation of the endless belt. Accordingly, it functions to improve the electrical, physical, and chemical properties simultaneously. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an endless belt (endless belt) for an image forming apparatus, which has excellent mechanical properties such as bending resistance, surface characteristics, and electrical characteristics, and is excellent in toner transfer properties and toner cleaning properties, and is compatible with high image quality. The present invention relates to an image forming apparatus including an endless belt for an image forming apparatus.

  Conventionally, as an image forming apparatus such as an OA device, an electrophotographic system using a photoreceptor and toner has been devised and put on the market. These devices include conductive belts, intermediate transfer belts, transfer transfer belts, transfer separation belts, charging tubes, developing sleeves, fixing belts, toner transfer belts, etc., regardless of the presence or absence of seams, conductive, semiconductive, insulating Endless belts controlled to various electrical resistances are used.

  For example, the intermediate transfer device is configured to once form a toner image on an intermediate transfer member and then transfer the toner to paper or the like. An endless belt made of a seamless belt is used for charging and discharging the toner on the surface layer of the intermediate transfer member. The seamless belt is set to have different surface electric resistance and electric resistance in the thickness direction (hereinafter referred to as “volume electric resistance”) for each machine model, and is adjusted to be conductive, semiconductive, or insulative.

  The transport transfer device is configured to hold the paper once on the transport transfer body, transfer the toner from the photosensitive member onto the paper held on the transport transfer body, and further remove the paper from the transport transfer body by discharging. Has been. On the surface of the transport transfer body, an endless belt with or without a seam is used for charging or neutralizing paper. The endless belt is set to have different surface electric resistance and volume electric resistance for each machine model, like the intermediate transfer belt.

  FIG. 1 is a side view of a general intermediate transfer apparatus. In the figure, 1 is a photosensitive drum and 6 is a conductive endless belt. 1 is an electrophotographic process unit including a charging device 2, an exposure optical system 3 using a semiconductor laser as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged. The conductive endless belt 6 is wound around the transport 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 (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. This toner image is electrostatically transferred to the conductive endless belt 6 by the electrostatic transfer machine 10 and transferred to the recording paper 11 between the conveying roller 9 and the pressing roller 12.

  By the way, in the case of a conductive endless belt used in an image forming apparatus such as an electrophotographic copying machine or a printer, since it is functionally driven with a high tension and a high voltage for a long time by two or more rolls, it is sufficient. Mechanical and electrical durability is required.

  In particular, in the case of an intermediate transfer belt used in an intermediate transfer device or the like, an image is formed with toner on the belt and transferred to paper, so if the belt is loosened, stretched or meandered during driving, the image Due to misalignment, high dimensional accuracy (small circumferential length difference in belt width and uniform thickness), high elastic modulus (high tensile elastic modulus in belt circumferential direction), high bending resistance The thing excellent in (it is hard to break) is desired.

  In recent years, electrophotographic image forming apparatuses such as color laser printers and color LED printers have become more competitive with low-cost inkjet image forming apparatuses. Therefore, the electrophotographic image forming apparatus aims to differentiate it from the inkjet system with a high-speed printing technology, and an image forming apparatus that performs high-speed printing with a tandem conveyance transfer and intermediate transfer system in which four photoconductors are arranged. It has been commercialized. For this reason, further improvement in durability and prevention of image misalignment have become increasingly important for endless belts for image forming apparatuses.

  Conventionally, endless belts have achieved certain results by improving their materials. However, recently, not only high-speed printing but also the demand for improving image quality has been increasing. Especially, high-quality images can be obtained in a wide range of temperature and humidity environments, and only special paper for color printers. However, it is becoming particularly important for high-quality paper, recycled paper, backing paper, and OHP film to obtain high image quality for differentiation from inkjet printers.

  For this reason, development of polymerized toners has progressed, and toners with a small particle size of 4 to 6 μm and small variations in particle size have been commercialized, and improvements to surface properties, chemical properties, and electrical properties of transfer belts have been made. The demand is also increasing.

  In particular, in the case of a transfer belt used in an intermediate transfer device or the like, the toner on the photoconductor is directly transferred onto the transfer belt by electrostatic force (primary transfer), and after synthesizing a color image on the transfer belt, the toner is added. In order to transfer to paper with electrostatic force (secondary transfer), not only the electrical resistance characteristics such as the surface electrical resistance and volume electrical resistance characteristics of the transfer belt are important, but also the surface physical characteristics and surface chemical characteristics need to be improved. There is. For example, the surface of an endless belt is required to be smoother in order to improve the cleaning properties for toners having a smaller particle size in recent years. However, if the surface of the endless belt is too smooth, a blade that scrapes off residual toner. The friction of the toner increases, and troubles related to the toner cleaning property are likely to occur.

From the above, the following conditions <1> to <8> are required for the endless belt for an image forming apparatus such as a transfer belt in recent years.
<1> Has predetermined surface electrical resistivity and volume electrical resistivity in the semiconductor region, has little resistance variation, and has excellent toner releasability
<2> Moderately smooth surface and excellent toner cleaning performance
<3> Thin and uniform
<4> Strong mechanical strength (hard to stretch and hard to crack)
<5> Fluctuations in resistance, dimensions, and mechanical strength due to the environment (temperature and humidity) are small.
<6> Low cost
<7> A seamless and perfect circle (small difference in circumference in the belt width direction) belt
<8> High-quality prints on various paper types

Conventionally, for the purpose of improving the releasability of the toner transferred onto the transfer belt, a fluororesin or silicon resin is added to the base polymer such as a thermoplastic resin or a thermosetting resin, so that the surface energy of the transfer belt is increased. Has been proposed (Japanese Patent No. 2994653, Japanese Patent Laid-Open No. 2-212867).
On the other hand, as an inexpensive belt manufacturing method, a transfer belt manufacturing method using an extrusion molding method in which an annular die is attached to the tip of an extruder has been proposed.
Japanese Patent No. 2994653 JP-A-2-212867

  However, when a molding material in which a toner releasability-imparting component having a low surface energy such as a fluororesin or a silicone resin is added to a thermoplastic resin or a thermoplastic elastomer is extruded, the compatibility of the material is poor, so that it does not mix. In addition to adversely affecting the mechanical properties such as the bending resistance of the belt, there is a problem in that the toner surface cleaning property is impaired due to the deterioration of the surface roughness of the belt.

  The present invention solves the above-mentioned conventional problems, and has excellent mechanical properties such as bending resistance, surface characteristics, and electrical characteristics, and is excellent in toner transferability and toner cleaning properties. An object of the present invention is to provide an image forming apparatus including a belt and the endless belt for the image forming apparatus.

  As a result of diligent studies to solve the above problems, the present inventors have mixed an additional component having a specific dropping point, for example, a wax, at a predetermined ratio with respect to the melting point of the thermoplastic polymer component. We found that the problem could be solved.

  In an endless belt application used in an image forming apparatus, since the fixing member is in the apparatus, the thermoplastic polymer component which is the main component of the endless belt needs heat resistance. Therefore, a general-purpose resin having a low melting point (about 120 ° C.) such as a polyethylene resin is rarely used as the thermoplastic polymer component. Even when an extrusion molding method in which the residence time of the molding material is relatively long is adopted as the molding method of the endless belt, it is necessary to use a thermoplastic polymer component or additive having excellent heat resistance.

  When a wax that is a low molecular weight ester instead of a high molecular weight resin is added to the molding material of the endless belt that requires heat resistance, the wax is thermally decomposed and volatilized during heat kneading or heat extrusion molding. Gas may be generated in the material. For this reason, conventionally, wax is not generally added to an extrusion molding material, and even when wax is added, the amount added is limited to a very small amount.

When the present inventors add a specific wax, that is, a wax having a specific drop point, in a specific blending amount, the mechanical properties are not adversely affected and the surface roughness is not deteriorated. Chemical and physical properties with excellent toner transfer and cleaning properties can be obtained. Dispersibility of conductive components such as carbon black is also improved, electric resistance is made uniform, and high image quality is supported. Of endless belts.
That is, the gist of the present invention is as follows.

(1) An endless belt used in an image forming apparatus, which is an endless belt mainly composed of a thermoplastic polymer component made of a thermoplastic elastomer and / or a thermoplastic resin, and has a melting point by DSC measurement of the thermoplastic polymer component. It is 130 ° C. or higher and 260 ° C. or lower, and contains an additional component having a dropping point of 50 ° C. or higher and 200 ° C. or lower in an amount of 0.1 parts by weight or more and less than 10 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. An endless belt for an image forming apparatus.

(2) An endless belt for an image forming apparatus, wherein the following conditions (1) to (4) are all satisfied in (1).
(1) Tensile modulus is 300 MPa to 2300 MPa
(2) Surface roughness Ra is 0.03 μm or more and 0.17 μm or less
(3) Outer surface contact angle with water is 70 ° or more and 90 ° or less
(4) SR (100V), the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds,
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
The following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300

(3) The endless belt for an image forming apparatus according to (1) or (2), wherein the additional component is a wax.

(4) The endless belt for an image forming apparatus according to (1) to (3), wherein the conductive component is contained in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component.

(5) In (1) to (4), the thermoplastic polymer component is a ratio of thermoplastic elastomer / thermoplastic resin = 5/95 to 95/5 by weight ratio of thermoplastic elastomer and thermoplastic resin. An endless belt for an image forming apparatus.

(6) The endless belt for an image forming apparatus according to any one of (1) to (5), wherein the thermoplastic elastomer is a polyester-based thermoplastic elastomer.

(7) The endless belt for an image forming apparatus according to any one of (1) to (6), wherein the thermoplastic resin contains polyalkylene terephthalate as a main component.

(8) An endless belt for an image forming apparatus according to (7), wherein the polyalkylene terephthalate is polybutylene terephthalate.

(9) The endless belt for an image forming apparatus according to any one of (4) to (8), wherein the conductive material is carbon black.

(10) In (9), wherein the carbon black, DBP oil absorption of 50 cm ^3/100 g or more 300 cm ^3/100 g or less and a specific surface area of ^35m 2 / g or more 500 meters ² / g or less, a volatile content of 0% or more and 20% or less, the average An endless belt for an image forming apparatus, characterized by being carbon black having a primary particle diameter of 20 nm to 50 nm and blended so as to satisfy the following formulas (i) and (ii).
Formula (i): LogY ≧ −X + 20
Formula (ii): LogY ≦ −X + 30
However, X and Y are as follows.
X: Carbon black content (% by weight) in the endless belt
Y: Surface electrical resistivity (Ω) at 100 V applied voltage, 10 seconds for endless belt

(11) The endless image forming apparatus according to (1) to (10), wherein the content of the additional component is 0.1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. belt.

(12) An endless belt for an image forming apparatus, wherein the molding material containing the thermoplastic polymer component and the additional component in (1) to (11) is extruded.

(13) The endless belt for an image forming apparatus according to (12), wherein the molding material further contains a chelator.

(14) The endless belt for an image forming apparatus according to (13), wherein the content of the chelator in the molding material is 0.01 to 50 times (weight ratio) with respect to the additional component.

(15) An endless belt for an image forming apparatus according to any one of (12) to (14), wherein the molding material is formed by pulling the molding tube heated and extruded from an annular die while cooling or solidifying it.

(16) The endless belt for an image forming apparatus according to any one of (1) to (15), which is a seamless intermediate transfer belt, conveyance transfer belt, transfer fixing belt, fixing belt, photoconductor belt, or development sleep .

(17) An endless belt for an image forming apparatus, which satisfies all of the following conditions (1) to (4):
(1) Tensile modulus is 300 MPa to 2300 MPa
(2) Surface roughness Ra is 0.03 μm or more and 0.17 μm or less
(3) Outer surface contact angle with water is 70 ° or more and 90 ° or less
(4) SR (100V), the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds,
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
The following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300

(18) An image forming apparatus comprising the endless belt for an image forming apparatus according to (1) to (17).

  By blending a thermoplastic polymer component having a melting point of 130 to 260 ° C. with an additional component having a dropping point of 50 to 200 ° C. at a predetermined ratio, the mechanical properties are not adversely affected, and the surface roughness is increased. It is possible to obtain chemical and physical properties excellent in toner transferability and cleaning property without deteriorating the toner, and to provide an endless belt capable of high image quality by making the electrical resistance value uniform.

  Although the details of the mechanism of the above effect according to the present invention in which a predetermined amount of a specific additional component is blended are not clear, the low energy and low molecular weight additional component having a predetermined dropping point is used when the molding material is kneaded. It is presumed that the electrical, physical and chemical characteristics are improved at the same time by moderately enhancing the dispersion effect of carbon black and the like, and appropriately bleeding out on the endless belt surface after molding the endless belt. .

According to the present invention, an endless belt for an image forming apparatus that satisfies all of the following conditions (1) to (4) is provided (claims 2 and 17).
(1) Tensile modulus is 300 MPa to 2300 MPa
(2) Surface roughness Ra is 0.03 μm or more and 0.17 μm or less
(3) Outer surface contact angle with water is 70 ° or more and 90 ° or less
(4) SR (100V), the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds,
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
The following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300

  A belt that has a tensile modulus of 300 MPa to 2300 MPa and is neither hard nor soft exhibits an effect of scraping toner from the photosensitive member in the primary transfer portion, and toner on uneven paper in the secondary transfer portion. Transfer efficiency can be improved. Further, it is effective for improving the toner transfer efficiency in the primary transfer and the secondary transfer that the surface roughness of the endless belt is moderately rough as 0.03 to 0.17 μm in Ra. Furthermore, the surface wettability represented by the contact angle with water is 70 ° or more and 90 ° or less, and is in an appropriate range that is neither hydrophilic nor hydrophobic, so that the toner transfer efficiency in the primary transfer portion is improved. It is effective for.

Further, in the endless belt for an image forming apparatus, satisfying the expression (a) means that the voltage dependency of the volume resistivity is larger than the voltage dependency of the surface resistivity. Further, satisfying the above formulas (b) and (c) indicates that the voltage dependency of the surface electrical resistivity is small and the voltage dependency of the volume electrical resistivity is moderately large. As described above, the voltage dependency of the volume resistivity is larger than the voltage dependency of the surface resistivity, and the voltage dependency of the volume resistivity is moderately large. At the time of the next transfer, the charge is moderately eliminated in the belt thickness direction, and as a result, the toner releasability effect by the self-discharge of the toner can be enhanced.
The toner releasability in the secondary transfer is supplemented by such electrical characteristics and the elastic characteristics, and as a result, the primary and secondary transfer efficiency of the toner can be improved.

  In the present invention, a wax is suitable as an additional component having a dropping point of 50 to 200 ° C. (Claim 3), and its content is 0.1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. It is preferable that there is (claim 11).

The endless belt of the present invention preferably further contains 0.1 to 30 parts by weight of a conductive component, preferably carbon black, relative to 100 parts by weight of the thermoplastic polymer component. In particular, DBP oil absorption of 50 cm ^3/100 g or more 300 cm ^3/100 g or less and a specific surface area of ^35m 2 / g or more 500 meters ² / g or less, a volatile content of 0% or more and 20% or less, the following carbon black having an average primary particle diameter of 20nm or more 50nm It is preferable to blend so as to satisfy the following formulas (i) and (ii) (claim 10).
Formula (i): LogY ≧ −X + 20
Formula (ii): LogY ≦ −X + 30
However, X and Y are as follows.
X: Carbon black content (% by weight) in the endless belt
Y: Surface electrical resistivity (Ω) at 100 V applied voltage, 10 seconds for endless belt
By blending carbon black as a conductive substance so as to satisfy the above requirements, it is possible to obtain good temperature and humidity environment stability and uniformity of electrical resistance value.

The endless belt for an image forming apparatus of the present invention includes a thermoplastic elastomer and a thermoplastic resin as a thermoplastic polymer component in a weight ratio of thermoplastic elastomer / thermoplastic resin = 5/95 to 95/5. Polyester-based thermoplastic elastomers are suitable as the thermoplastic elastomer, and polyalkylene terephthalate, particularly polybutylene terephthalate is preferred as the thermoplastic resin.
With such an alloy material of thermoplastic elastomer and thermoplastic resin, it is possible to obtain good durability and appropriate elastic modulus, satisfy the preferred electrical characteristics of the present invention, and good extrudability Can be obtained.

  In addition, the endless belt for an image forming apparatus of the present invention is preferably formed by extruding a molding material containing a thermoplastic polymer component and an additional component, and this molding material further includes a chelator with respect to the additional component. It is preferable to include 0.01 to 50 times (weight ratio) (claims 12, 13, and 14). By blending the chelator in such an amount, decomposition of additional components in the heat-kneading and heat-extrusion molding processes, gas generation is suppressed, and the effect of blending the additional components is fully exhibited and surface properties are excellent. You can get an endless belt.

  The endless belt for an image forming apparatus according to the present invention is preferably formed by taking out the molten material obtained by heating and extruding the molding material from an annular die while cooling or solidifying it.

  In this way, the endless belt obtained by extruding the tube extruded from the annular die by continuous extrusion in an annular state and pulling it as a cylindrical body, and cutting it into a ring, reduces cost and dimensional stability. Can be achieved at the same time. Further, by providing a plurality of temperature adjusting mechanisms in the circumferential direction of the annular die, an endless belt with little variation in electrical resistivity can be manufactured at low cost.

  The endless belt for an image forming apparatus of the present invention is particularly suitable for a seamless intermediate transfer belt, a conveyance transfer belt, a transfer fixing belt, a fixing belt, a photosensitive belt, or a development sleep.

  With the image forming apparatus of the present invention including such an endless belt for an image forming apparatus of the present invention, a high-quality image can be formed over a long period of time (claim 18).

  Hereinafter, embodiments of an endless belt for an image forming apparatus and an image forming apparatus according to the present invention will be described in detail.

(1) Endless belt material The endless belt of the present invention is blended as necessary with a thermoplastic polymer component comprising a thermoplastic elastomer and / or a thermoplastic resin, a specific additional component, more preferably a conductive material. It is composed of other additive components. The endless belt material according to the present invention may basically contain a specific additional component at a predetermined ratio with respect to the thermoplastic polymer component having a specific melting point, and there is no limitation on the types of other materials. Absent.

<Thermoplastic polymer component>
(Thermoplastic resin)
Examples of the thermoplastic resin used in the endless belt of the present invention include polypropylene, propylene ethylene block or random copolymer, rubber or latex component such as ethylene / propylene copolymer rubber, styrene / butadiene rubber, styrene / butadiene / styrene block copolymer. Polymer or hydrogenated derivatives thereof, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, liquid crystalline polyester, polysulfone, polyphenylene sulfide, polybisamidotriazole, acrylic, polyfluorinated vinylidene, polyfluorinated vinyl , Chlorotrifluoroethylene, acrylic acid alkyl ester copolymer, polyester ester copolymer, polyether ester copolymer, poly Teruamido copolymer, those composed of one or a mixture of two or more of these such as polyurethane copolymers can be used. Polyethylene (high density, medium density, low density, linear low density) has a melting point lower than 130 ° C. and is not suitable for the present invention. Polyimide, polyether imide, polyether ether ketone, ethylene tetrafluoroethylene copolymer, hexafluoropropylene, and perfluoroalkyl vinyl ether copolymer are not suitable for the present invention because their melting points are higher than 260 ° C.

  Among the thermoplastic resins used in the endless belt of the present invention, the crystalline resin preferably has at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and has a crystallinity of 20% or more and less than 90%. If it is, there will be no restriction | limiting in particular and a general purpose resin can be used.

  Specifically, among the thermoplastic crystalline resins, PAT (polyalkylene terephthalate) is preferable, and PBT (polybutylene terephthalate), PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) are more preferable, and PBT is crystallized. Since the speed is high, there is little change in crystallinity due to molding conditions, and it is particularly preferable because it is generally stable at a crystallinity of around 30%.

  Moreover, the crystalline resin used for this invention can also introduce | transduce a copolymerization component in the range which does not impair the effect of this invention remarkably. Specific examples include those in which an ester bond is a main chain and an ester bond such as polymethylene glycol is introduced.

  As the molecular weight of the thermoplastic crystalline resin used in the endless belt of the present invention, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used, but mechanical properties such as tensile elongation at break are high. When required, high molecular weight is preferred. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.

  Among the thermoplastic resins used in the endless belt of the present invention, the amorphous resin preferably has at least one of a hydroxyl group, a carboxylic acid group and an ester bond, and has a crystallinity of 0% or more and 10%. If it is less than this, there will be no restriction | limiting in particular and a general purpose resin can be used.

  Specifically, polyesters such as PC (polycarbonate) and PAr (polyarylate), and resins having ester bonds in the side chains such as PMMA (polymethyl methacrylate) can be given as suitable examples. Of these, polyester is preferable, and PC can be used particularly preferably.

  The amorphous resin used for the endless belt of the present invention can introduce a copolymer component within a range that does not significantly impair the effects of the present invention. Specific examples include those in which an ester bond is a main chain and an ester bond such as polymethylene glycol is introduced.

  The molecular weight of the amorphous resin used in the endless belt of the present invention 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. When there is a demand for high physical properties, high molecular weight materials are preferred. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.

(Thermoplastic elastomer)
As the thermoplastic elastomer used in the present invention, thermoplastic elastomers such as polyester, polyamide, polyether, polyolefin, polyurethane, and vinyl chloride can be used.

  The feature of the thermoplastic elastomer is that the crack resistance of the endless belt can be greatly enhanced and flexibility can be imparted.

(Alloy material of thermoplastic resin and thermoplastic elastomer)
When an alloy material of a thermoplastic resin and a thermoplastic elastomer is used as the thermoplastic polymer component, the thermoplastic elastomer has a common functional group with the thermoplastic resin and has high affinity with the thermoplastic resin. By using an elastomer, the alloy dispersibility of the thermoplastic resin and the thermoplastic elastomer is improved, the crack resistance can be dramatically improved and the tensile elastic modulus can be adjusted. Excellent surface smoothness, carbon black, etc. The conductive material dispersibility is obtained, which is preferable.

  Accordingly, when a polyester such as polybutylene terephthalate or polyethylene terephthalate and / or polycarbonate is used as the thermoplastic resin, it is preferable to use a polyester-based or polyether-based thermoplastic elastomer. In addition, it is preferable to combine a polyamide-based thermoplastic elastomer with an amide-based thermoplastic resin such as nylon.

  The polyester elastomer block is a polyester polyether block copolymer using an aromatic polyester as a hard component, an aliphatic polyether as a soft component, an aromatic polyester as a hard component, and an aliphatic polyester as a soft component. Copolymers can be used.

  More specifically, the following (A) and (B) can be used as the polyester polyether block copolymer and the polyester polyester block copolymer.

(A) Polyester polyether block copolymer The polyester polyether block copolymer comprises (a) an aliphatic and / or alicyclic diol having 2 to 12 carbon atoms, and (b) an aromatic dicarboxylic acid or an alkyl ester thereof. And (c) Polyalkylene ether glycol having a weight average molecular weight of 400 to 6,000 as a raw material, and an oligomer obtained by esterification reaction or transesterification reaction is polycondensed. Examples of the aliphatic and / or alicyclic diol having 2 to 12 carbon atoms include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Preferably, 1,4-butanediol and ethylene glycol are the main components, and one or a combination of two or more of these can be used.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and the like. Preferably, terephthalic acid and 2,6-naphthalenedicarboxylic acid are the main components. A combination of the above may also be used. Examples of the alkyl ester of aromatic dicarboxylic acid include dimethyl esters such as dimethyl terephthalate, dimethyl isophthalate, dimethyl phthalate, and 2,6-dimethyl naphthalate, preferably dimethyl terephthalate and 2,6-dimethyl naphthalate. There may be a combination of two or more of these. In addition to the above, trifunctional diols, other diols and other dicarboxylic acids and esters thereof may be copolymerized in small amounts, and aliphatic dicarboxylic acids such as adipic acid or alicyclic dicarboxylic acids, or What uses alkylester etc. as a copolymerization component is also good.

  As the polyalkylene ether glycol, those having a weight average molecular weight of 400 to 6,000 are used, preferably 500 to 4,000. Here, as polyalkylene ether glycol, polyethylene glycol, poly (1,2 and 1,3-propylene ether) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, block or random copolymer of ethylene oxide and propylene oxide And a block or random copolymer of ethylene oxide and tetrahydrofuran. Particularly preferred is polytetramethylene ether glycol. The content of the polyalkylene ether glycol is desirably 5 to 95% by weight, preferably 10 to 85% by weight, based on the block copolymer to be produced.

(B) Polyester polyester block copolymer The polyester polyester block copolymer is (d) an aliphatic or alicyclic dicarboxylic acid instead of the above (c) polyalkylene ether glycol having a weight average molecular weight of 400 to 6,000. And a polyester oligomer obtained by condensation of an aliphatic diol, (e) a polyester oligomer synthesized from an aliphatic lactone or an aliphatic monool carboxylic acid, and (a) an aliphatic and / or alicyclic group having 2 to 12 carbon atoms. A diol and (b) an aromatic dicarboxylic acid or an alkyl ester thereof are used as raw materials, and an oligomer obtained by an etherification reaction or a transesterification reaction is polycondensed.

  Examples of the above (d) include 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as dicyclohexyl-4,4′-dicarboxylic acid, or succinic acid, oxalic acid, adipic acid And polyester oligomers having a structure in which one or more aliphatic dicarboxylic acids such as sebacic acid and one or more diols such as ethylene glycol, propylene glycol, tetramethylene glycol, and pentamethylene glycol are condensed. Examples of e) include polycaprolactone-based polyester oligomers synthesized from ε-caprolactone, ω-oxycaproic acid and the like.

  Specific examples of thermoplastic elastomers other than polyesters used in the present invention include those based on polystyrene, such as styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene- There are ethylene-propylene-styrene copolymers, etc., and in the case of polyvinyl chloride, there are cross-linked (three-dimensional) vinyl chloride-linear vinyl chloride polymers, etc., and as olefins, there are polyethylene-EPDM copolymer, polypropylene-EPDM copolymer, polyethylene- There are EPM copolymer polypropylene-EPM copolymer, etc., and PBT (1,4-butadienediol-terephthalic acid condensate) -PTMEGT (polytetramethyleneglycol) (Poly-terephthalic acid condensate) copolymer and the like, and examples of the polyamide system include a copolymer having a basic skeleton of nylon oligomer-dicarboxylic acid-polyether oligomer, and examples of the nylon oligomer include nylon 6 and nylon. 66, nylon 610, nylon 612, nylon 11, nylon 12, and the like. As the polyether oligomer, for example, polyether glycol, polypropylene glycol, polytetramethylene glycol and the like can be used. Examples of the urethane system include a polyurethane-polycarbonate polyol copolymer, a polyurethane-polyether polyol copolymer, a polyurethane-polycaprolactone polyester copolymer, and a polyurethane-adibate polyester copolymer.

  When an alloy material of a thermoplastic resin and a thermoplastic elastomer is used as the thermoplastic polymer component, the weight ratio of the thermoplastic resin and the thermoplastic elastomer is not particularly limited. However, among thermoplastic resins, crystalline resins are generally excellent in chemical resistance and flex resistance, and amorphous resins are excellent in molding dimensional stability. Therefore, the ratio to thermoplastic elastomer is set according to the purpose of use. Among them, the weight ratio of thermoplastic resin / thermoplastic elastomer is preferably 1/99 to 99/1, more preferably 5/95 to 95/5, and still more preferably 10/90 to 90/10. 70/30 to 30/70 are particularly preferable, and 60/40 to 40/60 are particularly preferable.

  In this case, if the difference in viscosity between the thermoplastic resin and the thermoplastic elastomer is too large, even if the production conditions are adjusted, good dispersion may not be obtained, and uniform dispersion may not be achieved. Is preferably smaller. Specifically, the ratio of the thermoplastic resin and the thermoplastic elastomer measured by MFR under the same conditions is preferably within a range of about 1/20 to 20/1, and should be within a range of 1/10 to 10/1. More preferred.

  In addition, it is preferable to select the conditions close | similar to the processing temperature of a thermoplastic resin composition as measurement temperature conditions based on JISK-7210 as a measuring method of MFR. For example, when PBT and polyester elastomer are selected, it is preferable to set a processing temperature of 240 ° C. as the measurement temperature and compare the difference in viscosity between the two materials. Moreover, it can measure suitably by selecting 2.16 kg, for example as a load.

(Melting point of thermoplastic polymer component)
In the present invention, a thermoplastic polymer component having a melting point of 130 ° C. or higher and 260 ° C. or lower as measured by the following DSC measurement is used.
DSC (Differential Scanning Calorimetry) Measurement Using SSC-5200 (trade name) manufactured by Seiko Denshi Kogyo Co., Ltd., the sample was heated to 300 ° C. at a heating rate of 10 ° C./min, and the melting peak temperature was measured by DSC measurement. The melting point.

If the melting point of the thermoplastic polymer component is too low, it is preferable in that it does not impair the appearance because it is difficult to generate decomposition gas and volatile components because it is kneaded and extruded at a low temperature when the additional components described later are added. However, the heat resistance of the endless belt to be obtained is deteriorated, and not only the trace of the roller is easily made but also the creep property is deteriorated. On the other hand, if the melting point of the thermoplastic polymer component is too high, the molding temperature at the time of heat-kneading and heat-extrusion is too high, all the additional components volatilize and remain as gas in the belt material, and the appearance of the belt surface becomes rough.
The melting point of the thermoplastic polymer component is more preferably 180 ° C. or higher and 250 ° C. or lower, more preferably 200 ° C. or higher and 240 ° C. or lower.

  In addition, as a thermoplastic polymer component, 1 type (s) or 2 or more types of thermoplastic resins may be used, 1 type (s) or 2 or more types of thermoplastic elastomers may be used, and these may be mixed and used. .

  When a mixture of two or more materials is used as the thermoplastic polymer component, the melting point is a melting point measured by DSC measurement. If there are two or more peaks in this DSC measurement, the higher peak is heated. The melting point of the plastic polymer component.

<Additional ingredients>
In the present invention, an additional component having a dropping point of 50 ° C. or higher and 200 ° C. or lower is blended with the thermoplastic polymer component.

  If the dropping point of this additional component is too high, bleeding out from the endless belt is difficult, and chemical properties excellent in toner transfer and cleaning properties are difficult to obtain. On the other hand, if the dropping point of the additional component is too low, decomposition gas is likely to be generated, so that the belt surface is rough and it is difficult to obtain moderately smooth belt surface irregularities (physical properties). In addition, the bleed-out amount is large, and it is not preferable because it causes a problem that it adheres to the screw at the time of extrusion molding and cannot be extruded, the extrusion amount becomes unstable, and uneven thickness of the endless belt is likely to occur.

  The dropping point is a temperature at which the material becomes liquid above the temperature at which the material is softened by heating and drops from the bottom of the container of the measurement tester, and is measured by ISO 2176.

  Such additional components include waxes, ie, mixtures of esters of long chain aliphatic carboxylic acids and long chain aliphatic alcohols. The wax may be a natural wax or a synthetic wax, or a combination thereof.

Natural waxes include fossil waxes such as petroleum waxes and coal waxes, non-fossil waxes such as animal waxes and vegetable waxes, and synthetic waxes include semisynthetic waxes such as fatty acid amide waxes and nonpolar polyolefins. There are all synthetic waxes such as waxes, Fischer-Tropsch waxes and polar polyolefin waxes.
In particular, in order to improve the releasability between the toner and the endless belt and the effect of cleaning the toner remaining on the endless belt, montan wax (acid wax, ester wax, partially saponified ester wax, metal salt of montan acid) or polyolefin Wax (polyethylene wax, polypropylene wax, HDPE (high density polyethylene) oxidized wax, EVA wax, finely pulverized wax) is preferably added.
A commercially available product can be used as such a wax. For example, the following wax manufactured by Clariant Japan Co., Ltd. can be used.

  In the present invention, among these, polyethylene wax is preferably used because of its high surface energy, easy bleed out to the surface, and high bleed effect.

  The amount of such an additional component is 0.1 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. If the amount of this additional component is too large, the amount of bleed-out will be large, causing troubles that will stick to the screw during extrusion molding, making extrusion impossible, and the extrusion amount will become unstable. This is not preferable because unevenness in thickness tends to occur and bleed out from the endless belt becomes excessive, making it difficult to obtain a chemical substance excellent in toner transferability. On the other hand, if the amount of the additional component is too small, bleeding out from the endless belt is difficult, and chemical properties excellent in toner transfer and cleaning properties are difficult to obtain.

  The compounding amount of the additional component is more preferably 0.1 to 5 parts by weight, particularly preferably 1 to 2 parts by weight based on 100 parts by weight of the thermoplastic polymer component.

<Conductive substance>
By adding a conductive substance to the endless belt, the endless belt can be provided with conductivity and the degree of conductivity can be adjusted.

  The conductive material is not particularly limited as long as it satisfies the performance required for the application, and various materials can be used. Specifically, as the conductive filler, carbon black, carbon fiber, graphite, etc. Carbon-based fillers, metal-based conductive fillers, metal-oxide-based conductive fillers, and the like are used. In addition to the conductive fillers, ionic conductive substances such as quaternary ammonium salts are exemplified. Among conductive materials, it is preferable to use carbon black because the humidity dependency of the electrical resistivity tends to be reduced. Carbon black may be used in combination with other conductive materials such as an ion conductive material.

Although the compounding quantity of an electroconductive component changes also with the kind of electroconductive component to be used, it is preferable to set it as 0.1-30 weight part with respect to 100 weight part of thermoplastic polymer components. If the blending amount of the conductive component is less than this range, a sufficient blending effect cannot be obtained, and if it is too large, the moldability and the like are impaired.

In the present invention, DBP oil absorption amount as the carbon black for the following reasons 50~300cm ³ / 100g, a specific surface area 35~500m ² / g, volatile content 0-20%, carbon black is used to satisfy the average primary particle size 20~50nm It is preferable.

1) About the DBP oil absorption amount of carbon black The larger the DBP oil absorption amount of carbon black, the easier it is for carbon to form a bead-like chain (carbon structure), and the advantage that carbon agglomerates are less likely to occur, and the addition amount is small. However, on the other hand, the carbon chain was broken by various shearing forces applied to the resin containing carbon black in the process from compounding to molding, and the electrical resistivity was reduced. However, there is a problem that the fluctuations are not stable.
On the other hand, if the DBP oil absorption amount of carbon black is too small, it is difficult to form a carbon chain, so that the amount of carbon added for expressing conductivity is excessively increased, and there is a problem that the flex resistance of the material is impaired.
Thus preferred DBP oil absorption of carbon black is 50~300cm ³ / 100g.

2) About the particle size and specific surface area of carbon black The larger the specific surface area of carbon black, the more electrically conductive it appears with less added weight, so the mechanical strength is more advantageous in terms of resistance to cracking, but depending on the amount of carbon added. Since the conductivity tends to change abruptly, it is necessary to have a blending accuracy within ± 0.05% in order to control to the semiconductive region, and the resistance variation of the endless belt must be made uniform within ± 1 order. difficult. In addition, since carbon black with a large specific surface area generally has a small particle size, when dispersed in a resin, the carbon black particles are likely to be fooled. As a result, carbon aggregates are mixed in the molded product, and the location of the carbon aggregates Electricity concentrates on the surface, and partial dielectric breakdown is likely to occur. Also, if the specific surface area of carbon black is too small (carbon particles are too large), it is difficult to form carbon aggregates, so the appearance of the molded product is smooth, but the electrical conductivity is easily affected by the contact between the carbon particles. Since the resistivity tends to vary, it is preferable to select an optimized carbon particle size.
Accordingly, the average primary particle size of carbon black is preferably 20 to 50 nm, and the specific surface area is 35 to 500 m ² / g.

3) About the volatile matter of carbon black The more the volatile matter of carbon black, the better the carbon dispersion due to its surface characteristics, but it is more disadvantageous in molding because it generates gas during heating and kneading. Conversely, the smaller the volatile content of carbon black, the less the gas is generated during heating and kneading, so the moldability is better, but the carbon dispersion tends to deteriorate.
Therefore, the preferable volatile content of carbon black is 0 to 20%.

  There are no particular restrictions on the type of carbon black as long as it satisfies the DBP oil absorption, specific surface area, volatile content, and average primary particle size, and two types of carbon black can be used. It may be above.

  For example, as the type of carbon black, acetylene black, furnace black, channel black, and the like can be suitably used, and among these, acetylene black that has few functional groups as impurities and hardly causes poor appearance due to carbon aggregation can be particularly suitably used. . Moreover, there is no problem even if carbon black subjected to a known post-treatment step such as resin-coated carbon black, heat-treated carbon black, graphitized carbon black, or acid-treated carbon black is used.

  Furthermore, carbon black treated with a coupling agent such as silane, aluminate, titanate, and zirconate may be used for the purpose of improving dispersibility and suppressing gas generation.

In the present invention, the content of carbon black in the endless belt (hereinafter sometimes referred to as “carbon black concentration”) satisfies the following formulas (i) and (ii). This is preferable because the influence on the surface is reduced.
Formula (i): LogY ≧ −X + 20
Formula (ii): LogY ≦ −X + 30
However, X and Y are as follows.
X: Carbon black content (% by weight) in the endless belt
Y: Surface electrical resistivity (Ω) at 100 V applied voltage, 10 seconds for endless belt

That is, for example, in the case of a belt having a surface electrical resistivity of 1 × 10 ⁶ (Ω), the carbon black concentration is 14 to 24% by weight, and in the case of a belt having a surface electrical resistivity of 1 × 10 ¹⁰ (Ω). Has a carbon black concentration of 10 to 20% by weight, and in the case of a belt having a surface electrical resistivity of 1 × 10 ¹⁴ (Ω), a carbon black concentration of 6 to 16% by weight This is preferable in that it can be an endless belt with little variation in electrical resistivity against environmental variation at low humidity.

X and Y are particularly logY ≧ −X + 21
logY ≦ −X + 29
It is preferable that

  If the carbon black concentration is higher than the above range, the appearance of the product deteriorates due to the generation of decomposition gas etc. of the carbon black itself, and the polymer component decomposes due to the reaction between the carbon black and the thermoplastic polymer component, resulting in foaming. This is undesirable in appearance. Further, the folding resistance is also deteriorated.

  If the carbon black concentration is lower than the above range, the conductivity cannot be expressed, the carbon black dispersion state becomes rough, the electric resistivity tends to vary, and the contact resistance is greatly influenced by the environment. When mounted as an endless belt in an image forming apparatus, an image abnormality may occur depending on the environment.

<Polymerization catalyst>
In the present invention, when a thermoplastic resin and a thermoplastic elastomer are used in combination as a thermoplastic polymer component, a mixture of a thermoplastic resin and a thermoplastic elastomer, a mixture of them from a polymerization stage, and a reaction with a catalyst. Although known alloying techniques such as mixing while mixing can be used, heating and mixing using a polymerization catalyst is most preferable from the viewpoint of cost.
The polymerization catalyst is not particularly limited as long as it has the ability to polymerize thermoplastic resins and thermoplastic elastomers.

  Of the polymerization catalysts, Ti-based polymerization catalysts are preferred, and alkyl titanates can be suitably used.

  Among the alkyl titanates, tetrabutyl titanate or tetrakis (2-ethylhexyl) orthotitanate is preferable, and these are easily available as TYZOR TOT (manufactured by DuPont) or TYZOR TBT (manufactured by DuPont).

  In addition, the Ti-based polymerization catalyst is preferably combined with an alkali metal, alkaline earth metal-containing compound or zinc-containing compound because it works more effectively, and it is particularly preferable to have a magnesium-containing compound as the polymerization catalyst.

  Although there is no restriction | limiting in particular as a compound containing magnesium, Organic acid magnesium salt is preferable and magnesium acetate is especially preferable.

  If the amount of the polymerization catalyst used is too small, it may not work effectively. Therefore, it is preferable that the polymerization catalyst is used to a certain extent. Specifically, the mass of the metal in the polymerization catalyst is the total thermoplastic polymer component (thermoplastic resin and heat 1 ppm or more is preferable with respect to the total of the plastic elastomer), more preferably 10 ppm or more, and particularly preferably 20 ppm or more. On the other hand, since ester resins are known to cause depolymerization in the presence of a large amount of heavy metals, it is preferable that they are small to some extent, specifically 10,000 ppm or less, more preferably 1000 ppm or less. 500 ppm or less is particularly preferable. In the following, the weight ratio of Ti and Mg of the polymerization catalyst to the total thermoplastic polymer components may be referred to as “Ti concentration” and “Mg concentration”.

<Killator>
If the activity of the polymerization catalyst is too high, depolymerization of the thermoplastic polymer component may be promoted, resulting in problems such as a decrease in mechanical properties due to a decrease in molecular weight and foaming due to the generation of a low molecular weight material. When a chelator having the ability to chelate is present, depolymerization can be suppressed. Therefore, it is preferable to use a chelator as necessary.
The chelator is also preferable for preventing the molding material used in the present invention from being thermally decomposed in the heat-kneading and thermoforming processes.

  There is no restriction | limiting in particular as a kind of chelator, A well-known chelator (antioxidant) can be used.

  Examples include phosphites, phosphates, phosphates, and hydrazines, such as Irgafos 168 (manufactured by Ciba Geigy Japan), PEP36 (manufactured by Asahi Denka Kogyo Co., Ltd.). , Phosphorous ester of Sandstub P-EPQ (manufactured by Clariant Japan Co., Ltd.), IRGANOX MD1024 (manufactured by Ciba Geigy Japan Co., Ltd.), hydrazines of CDA-6 (manufactured by Asahi Denka Kogyo Co., Ltd.), etc. It can be obtained from the market.

  In the present invention, by suppressing the depolymerization and low molecular weight generation by optimizing the molding conditions, it is possible to add no chelator, but when it is necessary to suppress the depolymerization, the addition amount of the chelator is the total heat It is preferable to add 0.001 part by weight or more with respect to 100 parts by weight of the plastic polymer component, and it is preferable to add 0.1 part by weight or more to obtain a better effect.

  If the amount of the chelator is too large, the polymerization catalyst loses its activity and an endless belt having good physical properties may not be obtained. Therefore, it is preferable not to add too much, and 10 parts by weight with respect to 100 parts by weight of the total thermoplastic polymer component. The following is preferable, and it is more preferable that it is 5 parts by weight or less.

  In general, it is preferable to use a chelator as a small amount of 0.1 parts by weight or less with respect to 100 parts by weight of the total thermoplastic polymer component. As an example of preferable usage, the polymerization catalyst is added in an amount as large as 50 to 500 ppm, and the chelator is also 0.1 to 3 parts by weight, preferably 0.3 to 1 part by weight with respect to 100 parts by weight of the thermoplastic polymer component. In the range of 0.01 to 50 times (weight ratio) with respect to the additional components, particularly 0.1 to 10 times and higher than common sense, molding conditions (temperature, residence) for obtaining an endless belt When the time and the like are optimized, it is possible to suppress the depolymerization and prevent the decomposition of additional components while promoting the formation of a chemical bond and an increase in molecular weight between the thermoplastic resin and the thermoplastic elastomer. It is possible to obtain an excellent endless belt of no physical properties to come.

<Other optional ingredients>
In the endless belt of the present invention, optional blending components other than the above can be blended according to various purposes.

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

  Furthermore, compounding materials such as various thermoplastic resins, various elastomers, thermosetting resins, and fillers can be blended as the second and third components within a range that does not significantly impair the effects of the present invention.

  Thermoplastic resins include polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex components such as ethylene / propylene copolymer rubber, styrene Butadiene rubber, styrene / butadiene / styrene styrene block copolymer or its hydrogenated derivatives, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyimide, liquid crystalline polyester, polysulfone, polyphenylene sulfide, poly Bisamidotriazole, polyetherimide, polyetheretherketone, acrylic, polyfluorinated vinylidene, polyfluorinated vinyl, chlorotrifluoroethylene, ethylene Lafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, acrylic acid alkyl ester copolymer, polyester ester copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer What consists of 1 type, such as coalescence, or these mixtures can be used.

  As a thermosetting resin, what consists of 1 type, such as an epoxy resin, a melamine resin, a phenol resin, unsaturated polyester resin, or these mixtures, for example can be used. Examples of various fillers include calcium carbonate (heavy and light), talc, mica, silica, alumina, aluminum hydroxide, zeolite, wollastonite, diatomaceous earth, glass fiber, glass beads, bentonite, asbestos, and hollow. Glass ball, graphite, molybdenum disulfide, titanium oxide, carbon fiber, aluminum fiber, styrene steel fiber, brass fiber, aluminum powder, wood powder, rice husk, graphite, metal powder, conductive metal oxide, organometallic compound, organic In addition to fillers such as metal salts, additives such as antioxidants (phenolic, sulfur, phosphate ester, etc.), lubricants, various organic and inorganic pigments, UV inhibitors, antistatic agents, dispersants, neutralization Agents, foaming agents, plasticizers, copper damage inhibitors, flame retardants, crosslinking agents, flowability improvers, and the like.

(2) Endless belt manufacturing method <Heat kneading and molding>
In the present invention, the thermoplastic polymer component and the additional component, more preferably a conductive material, and if necessary, other optional components are heated and kneaded to form a thermoplastic resin composition, and then an endless belt is formed. Alternatively, the endless belt may be formed by heating and kneading these.

  In this case, the kneading conditions are such that the desired surface electrical resistivity can be obtained either by heating and kneading at the stage of obtaining the thermoplastic resin composition or by heating and kneading at the stage of molding the resin composition into an endless belt. Adjust. In any case, since sufficient dispersion is not possible unless it is in a molten state, it is preferable that the heating temperature be higher to some extent. Specifically, using the melting point of the crystalline resin as a guideline, it should be equal to or higher than the melting point of the crystalline resin. Is preferable, and it is more preferable that it is melting | fusing point +10 degreeC or more. Further, if the heating temperature is too high, thermal decomposition may be caused and physical properties may be deteriorated. Specifically, using the melting point of the crystalline resin as a guide, the melting point of the crystalline resin is preferably + 80 ° C. or lower, more preferably the melting point + 60 ° C. or lower.

  In addition, it is preferable to dry the raw material before drying by heating since the raw material may be dried to obtain an endless belt having better physical properties. In some cases, the mixture may be heat-kneaded to obtain a thermoplastic resin composition, and after heat treatment at a melting point or lower to form an ester bond, it may be formed into an endless belt.

  In the present invention, when a thermoplastic elastomer and a thermoplastic resin are used in combination as the thermoplastic polymer component, a specific dispersion state of the thermoplastic elastomer and the thermoplastic resin is a good dispersion of the conductive material and the surface of the endless belt. It is considered that an endless belt excellent in both toner transferability and releasability can be obtained. Accordingly, since the temperature during heat kneading and the time for receiving heat are important, it is desirable to set the heat kneading conditions while grasping the dispersion form of the obtained endless belt. At that time, the index of the alloy state is the voltage dependency characteristic of the electrical resistivity, the variation of the electrical resistivity, and the ratio of the surface electrical resistivity and the volume electrical resistivity.

  There is no particular limitation on the heating and kneading means, and a known technique can be used. For example, if a thermoplastic polymer component, an additional component, a conductive component blended as necessary, and other additive components are heated and kneaded to obtain a resin composition, a single screw extruder, twin screw kneading extrusion Machines, Banbury mixers, rolls, brabenders, plastographs, kneaders and the like can be used. In particular, a method in which these are mixed, for example, by a twin-screw kneading extruder, pelletized, and then formed into an endless belt is particularly preferably used.

  The molding method is not particularly limited, and a belt that employs a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, an inflation molding method, a centrifugal molding method, or a rubber extrusion molding method. Of particular interest is the continuous melt extrusion process. In particular, an extrusion molding method in which a molten tube extruded from an annular die is drawn while being cooled or cooled and solidified is preferable, and a downward extrusion type internal cooling mandrel method or a vacuum sizing method capable of controlling the inner diameter of the tube with high accuracy is particularly preferable. In particular, the inner cooling mandrel system is most preferable as a method for forming an endless belt for an image forming apparatus because a seamless endless belt can be easily obtained. In this case, the annular die is preferably provided with a plurality of temperature adjusting mechanisms in the circumferential direction. The melting tube is preferably cooled by bringing a mold whose temperature is adjusted in the range of 30 to 150 ° C. into contact with the inside or the outside, and in this way, the melting tube is taken up while maintaining the cylindrical shape. It is preferable.

  In this case, the molding material preferably has a melt viscosity of 0.1 g / 10 min or more in terms of MFR value (240 ° C., 2.16 kgf load). When the melt viscosity of the molding material is less than 0.1 g / min MFR, the fluidity at the time of extrusion molding is poor, and in addition to difficulty in extrusion molding, the shear stress applied to the molten resin is increased, so resistance adjustment is difficult. However, when the melt viscosity of the molding material is excessively high, the melt tension is low, and it is difficult to maintain the tube state from the melted state until cooling and solidification, and therefore it is preferably 25 g / 10 min or less. It is preferably 5 to 20 g / 10 minutes. Therefore, it is preferable to adjust the viscosity with a viscous polymer as necessary so that such a melt viscosity can be obtained.

In addition, once a film with creases is produced by the inflation molding method, there is no problem even if it is used as an endless belt in a state in which the creases are not visible in post-processing. It can be an endless belt with seams.
However, as the take-up means, a molding method is preferable in which the endless tube is taken up while being flattened without being flattened.

  Since an endless belt with better physical properties can be obtained by optimizing the molding temperature, residence time, and the like, it is preferable to adjust the conditions according to each formulation.

<Heat treatment>
By heat-treating the endless belt thus obtained, an endless belt with improved physical properties can be obtained. In particular, the number of folding times and the tensile elastic modulus are improved.

Although the heat treatment conditions depend on the thermoplastic polymer component to be used, it is usually 60 to 200 ° C., preferably 70 to 120 ° C. for 5 to 60 minutes, preferably about 10 to 30 minutes.
The heat treatment of the endless belt may be performed by applying heat while driving the belt while being stretched around two or more rollers, or may be performed by attaching an endless belt to a cylindrical mold. Furthermore, the heat treatment may be performed in a cylindrical shape.

(3) Physical properties of endless belt <Surface electrical resistivity and volume electrical resistivity>
The endless belt for an image forming apparatus of the present invention is
SR (100 V) is the surface electrical resistivity measured at an applied voltage of 100 V for 10 seconds.
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
It is preferable that the following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300

  That is, the rate of change represented by the maximum / minimum value (MAX / MIN) of the surface electrical resistivity measured at an applied voltage of 100 to 500 V (hereinafter sometimes referred to as “surface electrical resistance rate of change”) SR ( 100V) / SR (500V) is 100 times or less and the change rate represented by MAX / MIN of the volume resistivity measured at an applied voltage of 100 to 250V (hereinafter sometimes referred to as "volume resistivity change rate"). There is a relationship between the surface electrical resistance change rate SR (100 V) / SR (500 V) and the volume electrical resistance change rate VR (100 V) / VR (250 V) when VR (100 V) / VR (250 V) is 5 to 300. Is preferably surface electrical resistivity <volume electrical resistivity, that is, SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V).

  The characteristic that the rate of change in surface electrical resistance is small is important in that the toner is uniformly transferred even when the voltage applied by a roller or the like is changed, but the rate of change in volume electrical resistance is greater than the rate of change in surface electrical resistance. This is because the charged toner remaining on the belt that has not been subjected to the secondary transfer can be easily cleaned by the self-removing cleaning member, and the toner transfer efficiency on the belt during the secondary transfer can be improved. is there.

  The preferred surface electrical resistance change rate SR (100 V) / SR (500 V) is within 10 times, and the relationship between the volume electrical resistance change rate VR (100 V) / VR (250 V) is twice the surface electrical resistance change rate. It is preferable that the volume electric resistance change rate or less. The lower limit of the surface electrical resistance change rate is not particularly limited, but is usually about 1.5.

  In addition, if the volume electric resistance change rate VR (100 V) / VR (250 V) is too large, there is a problem in that current leaks due to voltage fluctuation. Therefore, the volume electric resistance change rate VR (100 V) / VR (250 V) is Within 300 times, preferably within 100 times. The lower limit of the volume electric resistance change rate VR (100 V) / VR (250 V) is 5 or more, particularly 10 or more in terms of exhibiting the effect of giving the belt a self-discharge function.

Accordingly, the endless belt for an image forming apparatus of the present invention preferably satisfies the following formulas (a ′), (b ′), and (c ′).
Formula (a ′): SR (100 V) / SR (500 V) × 2 ≦ VR (100 V) / VR (250 V)
Formula (b ′): 5 ≦ SR (100 V) / SR (500 V) ≦ 10
Formula (c ′): 10 ≦ VR (100 V) / VR (250 V) ≦ 100

The resistance region of the endless belt for an image forming apparatus of the present invention varies depending on the purpose of use, but the surface electrical resistivity 1 × 10 ⁶ × 10 ¹⁴ Ω or the volume electrical resistivity 1 × 10 ⁶ to 1 × 10 ¹⁴ Ω · It is selected from the range of cm.

Although the more preferable range of the resistance region varies depending on the application, for example, when used as a photoreceptor belt, the surface electrical resistivity 1 × 10 ¹ to 1 × 10 ⁹ so that the charge on the outer surface can be released to the inner surface as necessary. Low resistivity such as Ω or volume electrical resistivity 1 × 10 ¹ to 1 × 10 ⁹ Ω · cm is preferable, and when used as an intermediate transfer belt, surface electrical resistivity 1 × 10 ⁶ to 1 that can be easily charged and transferred. × 10 ¹³ Ω or volume electric resistivity 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm is preferable, and when used as a transfer transfer belt, it is easily charged and is not easily damaged even at a high voltage. 1 × 10 ¹⁰ to 1 × 10 ¹⁶ A high region such as Ω or volume resistivity 1 × 10 ¹⁰ to 1 × 10 ¹⁶ Ω · cm is preferable.

  Further, it is preferable that the distribution of the surface electrical resistivity in one endless belt is narrow, and in each preferable surface electrical resistivity region, the difference between the maximum value and the minimum value in one belt is within two digits (maximum The value is preferably 100 times or less of the minimum value).

  The surface electrical resistivity and volume electrical resistivity of the endless belt should be easily measured by, for example, “HIRESTA”, “Loresta” manufactured by Dia Instruments Co., Ltd., or “R8340A” manufactured by ADVANTEST Co., Ltd. Can do.

<Tensile modulus>
The tensile elastic modulus of the endless belt of the present invention is preferably 300 MPa or more and 2300 MPa or less. If the tensile elastic modulus of the endless belt is low, for example, when it is used in an image forming apparatus as an intermediate transfer belt, a slight elongation may occur due to the tension, which may cause problems such as color misregistration. If it is too high, a motor load will be applied when driving the belt, so it will be necessary to reduce the thickness setting.If dust gets in between the roller and the belt, or if scratches due to friction with the photosensitive member enter, cracks will occur. Since it is easy to enter and there is a problem in reliability, it is not preferable. Further, in order to improve the transfer efficiency of the toner in the primary transfer, it is necessary to have a tensile elastic modulus that does not allow the belt to stretch and a tensile elastic modulus that does not cause the endless belt to become hard. Therefore, the preferable range of tensile modulus is 300 MPa or more and 2300 MPa or less, particularly 500 MPa or more and 2000 MPa or less, and particularly preferably 600 MPa or more and 1800 MPa or less.

  The tensile elastic modulus of the endless belt is adjusted from the viewpoint of improving the transfer efficiency of the toner. As described above, the effect of improving the transfer efficiency of the toner due to the chemical characteristics (contact angle with water) of the belt surface, and the toner due to the electrical characteristics The most appropriate range may be determined in relation to the transfer efficiency improvement effect.

<Contact angle with water>
The contact angle between the outer surface of the endless belt of the present invention and water is preferably 70 ° or more and 90 ° or less. If the contact angle of the outer surface with water is less than 70 °, the toner adheres to the belt surface and forms a film, which deteriorates the toner secondary transfer efficiency. On the other hand, if it exceeds 90 °, the transfer efficiency of the toner is deteriorated in the primary transfer. Therefore, the contact angle between the outer surface of the endless belt of the present invention and water is preferably 70 ° or more and 90 ° or less, and particularly preferably 65 ° or more and 85 ° or less.

<Surface roughness Ra>
The surface roughness Ra of the endless belt of the present invention is preferably 0.03 μm or more and 0.17 μm or less. When the surface roughness Ra is less than 0.03 μm, the toner primary transfer efficiency is deteriorated. On the other hand, if it exceeds 0.17 μm, the secondary transfer efficiency of the toner deteriorates. Accordingly, the surface roughness Ra of the endless belt of the present invention is preferably 0.03 μm or more and 0.17 μm or less, particularly 0.05 μm or more and 0.15 μm or less.

<Folding resistance>
When the endless belt of the present invention is used as an intermediate transfer belt in an image forming apparatus, for example, an endless belt having good bending resistance is preferred because cracks occur and images cannot be obtained if the bending resistance is poor.

  The degree of bending resistance can be quantitatively evaluated by following the method for measuring the folding endurance of JIS P-8115, and it is judged that an endless belt with a higher folding endurance is less susceptible to cracking and has superior bending resistance. be able to.

  As a specific numerical value, if it exceeds 5000 times, it can be used with an excellent function as an endless belt for the life of the apparatus, but practically it is preferably 8000 times or more and preferably 10,000 times or more. More preferably.

  According to the present invention, depending on the amount of the thermoplastic elastomer added and alloying, the folding endurance of 50,000 times or more, and even 100,000 or more can be obtained. In order to prevent cracks from the end of the endless belt, It is preferable because sufficient crack resistance can be obtained without performing secondary processing such as a commonly used reinforcing tape for preventing cracks.

<Roller-resistant>
The roller wrinkle resistance of the endless belt of the present invention preferably has a roller wrinkle restoration rate of 25% or more determined in accordance with a roller wrinkle resistance evaluation method described later. If the anti-roller wrinkle is smaller than these condition ranges, the roller trace remaining on the endless belt may cause image unevenness. A more preferable roller-resistant wrinkle is 30% or more in terms of the roller wrinkle restoration rate, and particularly preferable is 35% or more.

(Endless belt thickness)
If the thickness of the endless belt is excessively large, if the curvature with the roller is large, the deformation difference between the outer side and the inner side of the belt is large and the endless belt is easily cracked. Further, the toner transferred to the outer side is deformed and scattered, and the image is deformed. On the other hand, if the thickness of the endless belt is excessively small, cracks are likely to occur due to slight scratches between the roller and the belt, or scratches due to contact with the photoreceptor, and the belt is likely to break. Therefore, the thickness of the endless belt of the present invention is preferably 70 to 300 μm, and particularly preferably 100 to 200 μm.

(5) Use of endless belt for image forming apparatus Although there is no particular limitation on the use of the endless belt for image forming apparatus of the present invention, the field of OA equipment, which has strict physical properties such as dimensional accuracy, bending resistance, and tensile modulus, is particularly functional. It can use suitably for a member. When this endless belt is formed in a seamless belt shape, there are few problems such as cracking and elongation, which is preferable.

  The endless belt for an image forming apparatus of the present invention can be suitably used for an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, or a facsimile machine, particularly as an intermediate transfer belt, a transfer transfer belt, a photoreceptor belt, or the like. .

  The endless belt of the present invention may be used as it is, or may be wound around a drum or a roll.

  Further, for the purpose of reinforcing the end face, a reinforcing tape such as a heat-resistant tape may be bonded to the outside and / or inside of the endless belt along the side edge as necessary. As the reinforcing tape, a biaxially stretched polyester tape is preferable from the viewpoint of cost and strength, and the tape width is preferably 4 mm or more and 20 mm or less because the apparatus layout is compact. The thickness of the reinforcing tape is preferably 20 μm or more and 200 μm or less from the viewpoint of being able to drive the endless belt with low tension and preventing the occurrence of cracking.

  For the purpose of preventing meandering of the endless belt, a rubber sheet (meandering preventing guide) such as urethane rubber or silicone rubber may be bonded to the side edge of the endless belt with an adhesive. In this case, the preferable sheet width of the rubber sheet to be used is 2 to 10 mm, and 3 to 8 mm is particularly preferable in view of the layout of the apparatus and the adhesive strength. Further, from the viewpoint of preventing meandering, the thickness of the meander-preventing rubber is preferably 0.5 to 3 mm, and more preferably 0.7 to 2 mm from the viewpoint of simplicity of the meandering prevention and meandering preventing effect.

  Furthermore, in combination with the above-mentioned reinforcing tape, it is preferable that the reinforcing tape is bonded to the endless belt and then the meandering prevention guide is bonded to the belt because of the effect of preventing the occurrence of belt cracking and the belt meandering.

  Examples 1 to 13 and Comparative Examples 1 to 5 are given below to show the effects of the present invention.

<material>
The following materials were used, and the blending ratios were as shown in Tables 4 and 5.

(Thermoplastic resin)
・ PBT1: "Novaduran 5040Z" manufactured by Mitsubishi Engineering Plastics
S "
Weight average molecular weight = 40,000
PS-converted weight average molecular weight = 122,000
MFR (240 ° C., 2.16 kgf load) = 4 g / 10 min. PBT2: “Novaduran 5010” manufactured by Mitsubishi Engineering Plastics Co., Ltd.
MFR (240 ° C., 2.16 kgf load) = 16 g / 10 minutes ETFE: “C55A” manufactured by Asahi Glass Co., Ltd.
Crystal melting point = 267 ° C.
・ PC: “E2000” manufactured by Mitsubishi Engineering Plastics Co., Ltd.
Weight average molecular weight = 28,000
PS-converted weight average molecular weight = 64,000
MFR (280 ° C., 2.16 kgf load): 4.8 g / 10 minutes

(Thermoplastic elastomer)
・ PEER1: Polyester-polyester elastomer “Perp” manufactured by Toyobo Co., Ltd.
Len S3001 "
MFR (240 ° C., 2.16 kgf load) = 21 g / 10 min
Crystal melting point = 216 ° C
・ PEER2: Polyester-polyester elastomer “Perp” manufactured by Toyobo Co., Ltd.
Len S2001 "
MFR (240 ° C., 2.16 kgf load) = 21 g / 10 min
Crystal melting point = 206 ° C
-PER: Polyester-ether elastomer "Perprene P1" manufactured by Toyobo Co., Ltd.
50B "
MFR (240 ° C., 2.16 kgf load) = 19 g / 10 min
Crystal melting point = 212 ° C

(Carbon black)
Denka Black manufactured by Electrochemical Co., Ltd.
DBP oil absorption = 180ml / 100g
Specific surface area = 65 m ² / g
Volatile content = 0%
Average primary particle size = 39 nm

(Polymerization catalyst)
Titanium (IV) butoxide / magnesium acetate

(Chelator)
Phosphorylation antioxidant “PEPQ” manufactured by Clariant Japan

(Additional ingredients)
Polyethylene wax 1: “Lico Wax PE52” manufactured by Clariant Japan
0 "
Drop point according to ISO 2176 = 118 ° C.
Polyethylene wax 2: “Lico Wax PE19” manufactured by Clariant Japan
0 "
Drop point according to ISO 2176 = 133 ° C
・ Montanic acid wax 1: “Lico Wax E” manufactured by Clariant Japan
Drop point according to ISO 2176 = 82 ° C.
・ Montannic acid wax 2: “Lico Wax OP” manufactured by Clariant Japan
Drop point according to ISO 2176 = 100 ° C.

(Polyethylene resin)
“HF310” manufactured by Nippon Polychem Co., Ltd.
Drop point according to ISO 2176> 200 ° C.

(Thickener)
Glycidyl methacrylate-containing polymer “Modiper A4400” manufactured by Nippon Oil & Fats Co., Ltd.
MI value according to JIS K7210 (190 ° C, 2.16 kgf load)
= 0.3 g / 10 min

  In addition, melting | fusing point calculated | required by DSC measurement about the thermoplastic polymer component was as showing in Table 4,5.

<Heat kneading>
Each raw material was pelletized using a twin-screw kneading extruder (“PMT32” manufactured by IKG Corporation). Conditions were as shown in Tables 4 and 5.

<Endless belt molding method>
This material pellet was dried, and the annular die was formed by an extruder of 40 mmφ with a six-spiral annular die having a diameter of 160 mm and a die slip width of 1.5 mm (having 16 temperature control mechanisms in the circumferential direction of the annular die). While extruding in the molten tube state downward, the extruded molten tube is in contact with the outer surface (temperature 80 ° C.) of a cooling mandrel having an outer diameter of 153 mm mounted on the same axis as the annular die via a support rod, and is cooled and solidified. Next, a length of 340 mm is taken while the seamless belt is being held in a cylindrical shape by a cylindrical core installed in the seamless belt and a four-point belt type take-up machine installed on the outside. And adjust the extrusion amount, take-up speed, and extrusion temperature so that the thickness becomes 140 μm and the surface electrical resistivity becomes 1 × 10 ¹⁰ to 1 × 10 ¹² Ω. A seamless belt with an inner diameter of 151 mm was prepared. The molding conditions were as shown in Tables 4 and 5.

In addition, for the molding material, a sample was taken for 5 to 1/6 minutes after the start of heating with a melt indexer “T-01” (240 ° C., 2.16 kgf load) manufactured by Toyo Seiki Co., Ltd., and the weight was measured. (M), and MFR was calculated by the following equation. However, since the molding material used in Comparative Example 4 had a melting point of 260 ° C. or higher, MFR was measured at 280 ° C. under a 2.16 kgf load. The MFR is as shown in Tables 4 and 5.
Formula: MFR = (600 × m) ÷ t (g / 10 minutes)
t = sampling time (seconds) (here 60 seconds)
m = weight of sampling (g)

<Evaluation>
The evaluation was carried out by cutting the endless belt to the required size as required, and the results are shown in Tables 6 and 7.

-Surface electrical resistivity A product name "Hiresta (UR terminal)" manufactured by Dia Instruments Co., Ltd. was used, and the belt circumferential direction was measured at a pitch of 20 mm under conditions of 100 V, 500 V, and 10 seconds each.

-Volume resistivity The product name "Hiresta (UR terminal)" manufactured by Dia Instruments Co., Ltd. was used, and the belt circumferential direction was measured at a pitch of 20 mm under conditions of 100 V, 250 V, and 10 seconds each.

-Tensile elastic modulus Based on ISO R1184-1970, the test piece was cut into a width of 15 mm and a length of 150 mm, and measured with a tensile speed of 1 mm / min and a distance between grips of 100 mm.

・ Bending resistance (bending resistance)
In accordance with JIS P-8115, the test piece was cut into a size of 15 mm in width and 100 mm in length, and was subjected to a bending speed of 175 times / min, a rotation angle of 135 ° left and right, and a tensile load of 1.0 kgf with an MIT tester Then, the number of bendings to breakage was measured with the radius of curvature of the tip of the bending jig being R = 0.38 mm.

・ Roller proof resistance As shown in FIG. 2A, a sample 31 having a width of 15 mm and a length of 44 mm is wound around the outer circumference of a roller 30 having a diameter of 14 mm, both ends are fixed with tape, and the temperature is 60 ° C. and the humidity is 90%. 2 hours, and further left for 24 hours in an environment of temperature 23 ° C. and humidity 50%. After that, the sample 31 is removed from the roller 30, and a sample with a flaw as shown in FIG. A distance L (mm) between both short sides of 31 was measured, and a roller wrinkle restoration rate was calculated by the following formula to obtain roller wrinkle resistance.
Roller wrinkle restoration rate = L / 44 x 100

-Contact angle with water A drop of water was dropped on the outer surface of the endless belt, and the contact angle of water after 1 minute was measured using an Elmer goniometer "G-1."

・ Surface roughness Cut the outer surface of the endless belt into a sample of about 50 mm × 50 mm, and using a key depth ultra-fine shape measurement microscope product name “VK8500” manufactured by Keyence Corporation, lens 100 times, pitch 0.01 μm, shutter speed AUTO, The surface roughness of a 40 μm × 40 μm area was measured at four points under the measurement condition of the gain 835, and the average value was used as the measured value of the surface roughness.

  In addition, among the comprehensive evaluations in Tables 6 and 7, “◯ −” is good but slightly inferior to “◯”, and “◯-” means slightly inferior to that.

<Discussion>
In Examples 1 to 4, a thermoplastic polymer component of PBT / polyester / polyether elastomer is added with a polyethylene wax, and the blend of PBT and polyester / polyether elastomer is changed. When the blending ratio is large, it is slightly soft and when it is small, it is slightly hard, but all have good characteristics. In Examples 1 and 3, a thickener is used in combination. The combined use of the thickener increases the viscosity of the material, and the effect of improving the dispersibility of carbon black is obtained.

  In Examples 1, 5 to 7, the addition amount of the polyethylene-based wax was changed with respect to the thermoplastic polymer component having the same composition, but the addition amount of the wax was 1.0 with respect to 100 parts by weight of the thermoplastic polymer component. It can be seen that particularly good characteristics can be obtained at about 2.0 parts by weight.

  Examples 1, 8, 9, and 10 and Examples 11 and 12 are obtained by changing the type of wax with respect to the thermoplastic polymer component having the same composition, but the polyethylene wax rather than the montanic acid wax. It can be seen that the effect of addition is higher.

  Examples 11 to 13 were obtained by changing the type of elastomer and further the wax, but all obtained good results.

  On the other hand, in the comparative example 1 of the PBT / polyester / polyether elastomer system to which no additional component wax is added, the resistance value is low and the voltage change of the resistance value is too large.

  Further, since the PBT / PC comparative example 2 to which no wax is added is too hard, the roller wrinkle affects the image.

In Comparative Example 3 in which the amount of added wax is too large, the surface roughness is significant.
In Comparative Example 4 in which ETFE having a melting point of 267 ° C. was used as the thermoplastic polymer component, since the melting point of the thermoplastic polymer component was too high, surface roughening was remarkable due to gasification of the wax.

  In Comparative Example 5 in which a polyethylene resin having a dropping point of more than 200 ° C. was added instead of the wax as an additional component, the surface roughness was remarkable and the folding resistance was low.

  From the above results, mechanical characteristics, electrical characteristics, and surface characteristics of the thermoplastic polymer component having a melting point of 130 to 260 ° C. are blended with a predetermined amount of an additional component having a dropping point of 50 to 200 ° C. It can be seen that all can provide an endless belt for an image forming apparatus with excellent image quality and high durability.

It is a side view of a general intermediate transfer device. It is a perspective view which shows the evaluation method of a roller wrinkle resistance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure optical system 4 Developing device 5 Cleaner 6 Conductive endless belt 7, 8, 9 Conveyance roller 30 Roller 31 Sample

Claims (18)

An endless belt used in an image forming apparatus, wherein the endless belt mainly contains a thermoplastic polymer component made of a thermoplastic elastomer and / or a thermoplastic resin.
The melting point by DSC measurement of the thermoplastic polymer component is 130 ° C. or higher and 260 ° C. or lower,
An endless belt for an image forming apparatus, comprising an additional component having a dropping point of 50 ° C. or higher and 200 ° C. or lower with respect to 100 parts by weight of the thermoplastic polymer component of 0.1 parts by weight or more and less than 10 parts by weight. 2. The endless belt for an image forming apparatus according to claim 1, wherein all of the following conditions (1) to (4) are satisfied.
(1) Tensile modulus is 300 MPa to 2300 MPa
(2) Surface roughness Ra is 0.03 μm or more and 0.17 μm or less
(3) Outer surface contact angle with water is 70 ° or more and 90 ° or less
(4) SR (100V), the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds,
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
The following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300   3. The endless belt for an image forming apparatus according to claim 1, wherein the additional component is a wax.   The endless belt for an image forming apparatus according to any one of claims 1 to 3, further comprising 0.1 to 30 parts by weight of a conductive component with respect to 100 parts by weight of the thermoplastic polymer component.   5. The thermoplastic polymer component according to claim 1, wherein the thermoplastic polymer component is a ratio of thermoplastic elastomer / thermoplastic resin = 5/95 to 95/5 by weight ratio of the thermoplastic elastomer and the thermoplastic resin. An endless belt for an image forming apparatus.   6. The endless belt for an image forming apparatus according to claim 1, wherein the thermoplastic elastomer is a polyester-based thermoplastic elastomer.   7. The endless belt for an image forming apparatus according to claim 1, wherein the thermoplastic resin contains polyalkylene terephthalate as a main component.   8. The endless belt for an image forming apparatus according to claim 7, wherein the polyalkylene terephthalate is polybutylene terephthalate.   9. The endless belt for an image forming apparatus according to claim 4, wherein the conductive material is carbon black. According to claim 9, wherein the carbon black, DBP oil absorption of 50 cm ^3/100 g or more 300 cm ^3/100 g or less and a specific surface area of ^35m 2 / g or more 500 meters ² / g or less, a volatile content of 0% or more and 20% or less, the average primary particle size An endless belt for an image forming apparatus, characterized by being carbon black of 20 nm or more and 50 nm or less and blended so as to satisfy the following formulas (i) and (ii).
Formula (i): LogY ≧ −X + 20
Formula (ii): LogY ≦ −X + 30
However, X and Y are as follows.
X: Carbon black content (% by weight) in the endless belt
Y: Surface electrical resistivity (Ω) at 100 V applied voltage, 10 seconds for endless belt   11. The endless image forming apparatus according to claim 1, wherein the content of the additional component is 0.1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. belt.   The endless belt for an image forming apparatus according to claim 1, wherein the molding material containing the thermoplastic polymer component and the additional component is extruded.   The endless belt for an image forming apparatus according to claim 12, wherein the molding material further includes a chelator.   14. The endless belt for an image forming apparatus according to claim 13, wherein the content of the chelator in the molding material is 0.01 to 50 times (weight ratio) with respect to the additional component.   15. The endless belt for an image forming apparatus according to any one of claims 12 to 14, wherein the molding material is formed by pulling the molding tube heated and extruded from an annular die while cooling or solidifying the tube.   16. The endless belt for an image forming apparatus according to claim 1, wherein the endless belt is an seamless intermediate transfer belt, a conveyance transfer belt, a transfer fixing belt, a fixing belt, a photosensitive belt, or a development sleep. . 2. The endless belt for an image forming apparatus according to claim 1, wherein all of the following conditions (1) to (4) are satisfied.
(1) Tensile modulus is 300 MPa to 2300 MPa
(2) Surface roughness Ra is 0.03 μm or more and 0.17 μm or less
(3) Outer surface contact angle with water is 70 ° or more and 90 ° or less
(4) SR (100V), the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds,
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
The volume resistivity when measured at an applied voltage of 100 V for 10 seconds is VR (100 V),
The volume resistivity when measured at an applied voltage of 250 V for 10 seconds is VR (250 V),
The following expressions (a), (b) and (c) are satisfied.
Formula (a): SR (100 V) / SR (500 V) <VR (100 V) / VR (250 V)
Formula (b): SR (100 V) / SR (500 V) ≦ 100
Formula (c): 5 ≦ VR (100 V) / VR (250 V) ≦ 300   An image forming apparatus comprising the endless belt for an image forming apparatus according to claim 1.

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