JP2005220269A - Conductive seamless belt, method for producing conductive seamless belt and image forming device provided with conductive seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive belt free from the problems of bleeding, blooming and contamination/transfer contamination of a photoreceptor, and having small scattering of the resistance value and extremely small environment dependency of resistance value. <P>SOLUTION: The conductive belt having a conductive layer is formed by using a polymer produced by compounding a thermoplastic polymer composition having a polyoxyalkylene structure and a salt having either one cation of chemical formulas 1-3 to a fluorine-based thermoplastic polymer and converting the fluorine-based polymer to be conductive by ionic conduction. The amount of the salt is ≥0.01 pt. wt. and ≤20 pts. wt. based on 100 pts. wt. of total polymer. In the formulas, X<SB>1</SB>, X<SB>2</SB>and X<SB>3</SB>are each a 1-8C functional group containing C, F and SO<SB>2</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive belt, a method of manufacturing a conductive belt, and an image forming apparatus provided with the conductive belt. Specifically, the compounding material for forming a conductive belt used in the image forming apparatus is improved. Without causing bloom / photoconductor contamination or the like, variation in resistance value and environmental dependency are reduced, and good electrical characteristics can be stably obtained.

  Conductive belts, transfer belts, intermediate transfer belts, fixing belts, development belts, belts for photoreceptor substrates, etc. in electrophotographic or electrostatic printing image forming apparatuses such as copying machines, facsimiles, printers, etc. A belt is used.

  In order to impart conductivity to this type of belt, a method of using an electronically conductive filler such as metal oxide powder or carbon black can be used. However, it is difficult to control the electronic conductive filler because the electrical resistance value changes abruptly due to a slight change in the amount of addition. In addition, since it is difficult to uniformly disperse the electronically conductive filler in the polymer, there is a problem that variation in electric resistance value becomes very large within the belt surface and between each product. Furthermore, there is a problem that the electric resistance value of the obtained belt changes depending on the applied voltage and does not show a constant resistance value. Such a phenomenon makes it difficult to perform mechanical control in an image forming process such as transfer / fixing, resulting in a cost increase.

  In view of the above, in recent image forming apparatuses that require high image quality and energy saving, ion conductive belts that can reduce variations in resistance value tend to be preferred. Conventionally, various proposals have been made to obtain even better electrical characteristics in such an ion conductive belt.

For example, in JP 2002-304064 A (Patent Document 1), a resin composition containing at least one thermoplastic resin, a hydrophilic resin that is incompatible with the thermoplastic resin, and an alkali metal salt. An endless belt obtained by extruding a product has been proposed.
In JP 2002-174933 A (Patent Document 2), 30 to 90% by weight of a thermoplastic resin and 2 to 2 compounds selected from the group consisting of polyetheresteramide, polyetherester and polyetheramide are used. An electrophotographic belt member containing 30% by weight, 0 to 5% by weight of an electrolyte, and 2 to 50% by weight of an insulating filler has been proposed.

JP 2002-304064 A

JP 2002-174933 A

  However, the belts of Patent Document 1 and Patent Document 2 have a problem that the resistance value is highly dependent on the environment (temperature dependency + humidity dependency), and the performance changes due to differences in the usage environment such as temperature and humidity. Although it is conceivable to specify the water absorption rate of the hydrophilic resin in order to improve the environmental dependency, it is difficult to drastically reduce the environmental dependency. In addition, the conductivity imparting performance of the additive salt described in the above-mentioned patent document is not sufficient, and in order to obtain a certain low electrical resistance, more additive salt and antistatic resin are required, and the workability and mechanical properties are deteriorated. There's a problem.

  As described above, if the electrical resistance value is highly dependent on the environment, it is necessary to cope with various usage environments. Therefore, in the image forming apparatus, a larger power supply device is required and a large voltage is required for transfer. There is a problem that resistance rise is large or transfer efficiency is low, and there is a problem that the control system becomes complicated.

Furthermore, when an ion conductive conductive plasticizer is used in an ion conductive belt, there is a problem that bleeding, bloom, and photoconductor contamination occur. Further, when a salt such as sodium perchlorate (NaClO ₄ ) is used, it is difficult to handle at the time of kneading with a thermoplastic elastomer or the like, so that there is a problem that good electrical characteristics cannot be obtained. Therefore, in particular, it is desired to reduce the environment dependency of the ion conductive thermoplastic material.

  The present invention has been made in view of the above-described problems, and does not cause a problem of bleed, bloom, photoconductor contamination or migration contamination, and has a small variation in resistance value, and the environmental dependency of the resistance value. It is an object to provide a conductive seamless belt having a very small size.

  In order to solve the above-mentioned problems, the present invention relates to a thermoplastic thermoplastic composition having a polyoxyalkylene structure and a salt having an anion according to any one of the following chemical formulas 1 to 3. Blended into a coalescence and formed from a polymer obtained by ion-conducting a fluorinated thermoplastic polymer, and the salt is blended at a ratio of 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total polymer An electrically conductive seamless belt is provided.

（式中、Ｘ₁，Ｘ₂，Ｘ_３は、Ｃ，−Ｆ，−ＳＯ₂−を含む、炭素数が１〜８の官能基）

(Wherein X ₁ , X ₂ and X ₃ are functional groups having 1 to 8 carbon atoms, including C, —F and —SO ₂ —).

  The present invention pays attention to the salt and polymer material used in the compounding material of the belt, and as a result of the inventor's examination and accumulation of the material type and compounding amount, the resistance value variation and the voltage dependency are small, and the bleed This is based on the finding of a composition that can obtain a belt having a low resistance dependency on the environment, in particular, without causing bloom or photoreceptor contamination / migration contamination.

The above-mentioned chemical formulas 1 to 3, in particular, the salt having an anion according to either chemical formula 1 or chemical formula 3 exhibits ionic conductivity when used in combination with a thermoplastic polymer composition having a polyoxyalkylene structure. . The salt having an anion described in Chemical Formulas 1 to 3 (Chemical Formulas 1 to 3) is stable as an anion due to the electron withdrawing property of the fluoro group and sulfonyl group in the functional groups of X ₁ , X ₂ and X _3. And ions exhibit a higher degree of dissociation. Thereby, a very low electric resistance value can be obtained with a small amount of addition. Further, according to this salt, the electric resistance can be easily adjusted, and variation in resistance value within the belt surface and between products can be reduced. In addition, these salts are chemically stable, have a wide usable temperature range, do not decompose or deteriorate even at the molding temperature of the thermoplastic resin, and are powdered at room temperature, easy to knead, The surface skin can be smoothed even by extrusion molding. Among them, a salt having an anion described in Chemical Formula 1 or Chemical Formula 3 is preferable in terms of conductivity and chemical stability.

The fluorine-based thermoplastic polymer is 90 parts by weight or less and 40 parts by weight or more with respect to 100 parts by weight of the total polymer, and the salt is 0.1% of the weight of the thermoplastic polymer composition having the polyoxyalkylene structure. 20% or less,
The glass transition temperature Tg of the thermoplastic polymer composition having a polyoxyalkylene structure is preferably −40 ° C. or lower.

The weight of the salt having an anion according to any one of the chemical formulas 1 to 3 is 0.1% or more and 20% or less of the weight of the thermoplastic polymer composition having the polyoxyalkylene structure. If the content is less than 1%, the salt concentration becomes low, and it becomes difficult to sufficiently reduce the electric resistance value of the belt. This is because if it exceeds 20%, the processability deteriorates and the cost increases, or the salt precipitates from the polymer composition.
Thus, conductivity is obtained by using the salt having an anion according to any one of chemical formulas 1 to 3 together with the thermoplastic polymer composition having the polyoxyalkylene structure, and the resistance value varies. Reduction and reduction of the environmental dependency of the resistance value can be realized very efficiently.

  It is sufficient that the salt provided with the anion according to any one of the chemical formulas 1 to 3 is 0.01 part by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total polymer if less than 0.01 part by weight. The electrical resistance cannot be reduced, and even if it is contained in an amount of more than 20 parts by weight, the effect of reducing the resistance value is almost saturated, and it is difficult to further reduce the resistance value, and the cost is meaninglessly increased. This is because the salt may be precipitated. More preferably, it is 0.1 to 10 parts by weight, and more preferably 0.4 to 6 parts by weight.

The reason why the glass transition temperature Tg of the thermoplastic polymer composition having a polyoxyalkylene structure is −40 ° C. or lower is that when Tg is higher than −40 ° C., the environmental dependency of the resistance value increases. Furthermore, -50 degrees C or less is preferable. Moreover, it is preferable that the thermoplastic polymer composition which has a polyoxyalkylene structure has the temperature dependence of the elasticity modulus between 10 degreeC-32.5 degreeC as small as possible.
As described above, when the Tg is in a region where the temperature is low to some extent, the temperature dependency of the elastic modulus change in the belt operating temperature region is small, whereby the environmental dependency of the electrical resistance can be reduced. In addition, although Tg of the said thermoplastic polymer composition is so preferable that it is low, it is preferable that it is about -80 degreeC or more actually from a viewpoint of cost or water resistance.

  When the fluorine-based thermoplastic polymer is 40% or more and 98% or less of the total polymer weight, the belt can be provided with flame retardancy because it contains a large amount of fluorine. Preferably it is 50% or more. The higher the ratio of the fluorine-based thermoplastic polymer, the better. However, since it is necessary to include a thermoplastic polymer composition having a polyoxyalkylene structure necessary for imparting conductivity, the upper limit is about 98% by weight. In order to further reduce the environmental dependency, the glass transition temperature Tg of the fluorinated thermoplastic polymer is preferably −40 ° C. or lower, and the temperature dependence of the elastic modulus between 10 ° C. and 32.5 ° C. It is preferable that the property is as small as possible. As the fluorine-based thermoplastic polymer, one or more kinds of various fluorine resins such as polyvinylidene fluoride (PVDF) can be used.

The salt having an anion according to any one of chemical formulas 1 to 3 is uniformly dispersed in the thermoplastic polymer composition having the polyoxyalkylene structure, and has a polyoxyalkylene structure in which the salt is dispersed. The thermoplastic polymer composition is preferably uniformly dispersed in the fluorine-based thermoplastic polymer.
This prevents the salt from flowing out of the polymer when an electric field is applied, reducing the environmental dependency of the resistance value and preventing the salt from moving out of the polymer or increasing the resistance during continuous energization. be able to.

The conductive layer is a low-temperature low-humidity environment (10 ° C., 15% relative humidity) and a volume resistivity R _LL at high temperature and high humidity environment (32.5 ° C., 90% relative humidity) the volume resistivity R _HH in the, log ₁₀ It is preferable that the relationship of R _LL -log ₁₀ R _HH ≦ 1.8 is satisfied. If the above relationship is satisfied, the electrical resistance does not fluctuate even when the usage environment changes, and is particularly suitable for an intermediate transfer belt. The value of (log ₁₀ R _LL -log ₁₀ R _HH ) is more preferably 1.6 or less, more preferably 1.4 or less, and most preferably 1.1 or less.

In the anions described in the above chemical formulas 1 to ₃ , each of X ₁ , X ₂ and X ₃ is a functional group having 1 to 8 carbon atoms including all of C, —F and —SO ₂ —. In view of stability, cost, and handleability, X _1-in Chemical Formula 1 is C _n1 H _m1 F _{(2n1-m1 + 1)} -SO _2- and X ₂ -is C. _{n2 H m2 F (2n2-m2} + 1) -SO 2 - and is, _{X 3} - is _{C n3 H m3 F (2n3-} m3 + 1) -SO 2 - (n1, n2, n3 is an integer of 1 or more, m1, m2 and m3 are preferably integers of 0 or more.

  The cation constituting the salt paired with the anion described in any one of the chemical formulas 1 to 3 is a cation of any one of an alkali metal, a group 2A element, a transition metal, and an amphoteric metal. Among them, alkali metals are easy to form stable cations because of low ionization energy, and lithium and potassium are particularly preferable.

In addition to the metal cation, a salt having a cation represented by the following chemical formula 4 (Chemical formula 4), chemical formula 5 (Chemical formula 5), and chemical formula 6 (Chemical formula 6) can also be used. In the formula, R _{1 to} R ₁₀ are each an alkyl group having 1 to 20 carbon atoms or a derivative thereof, and R _{1 to} R ₄ , R ₅ and R _6, and R _{7 to} R ₁₀ may be the same or different. Things can be used. Among these, a trimethyl type quaternary ammonium cation in which three of R _{1 to} R ₄ are methyl groups and the other is an alkyl group having 4 to 20 carbon atoms, more preferably 6 to 20 carbon atoms, or a derivative thereof. Is particularly preferred because the positive charge on the nitrogen atom can be stabilized by three methyl groups having strong electron donating properties, and the compatibility with the polymer can be improved by other alkyl groups or derivatives thereof. In addition, in the cation of the formula 5, the R ₅ or R ₆ having an electron donating property also improves the stability as a cation by stabilizing the positive charge on the nitrogen atom, It is possible to obtain a salt having a high degree of dissociation and thus excellent conductivity imparting performance. Therefore, R ₅ or R ₆ is more preferably a methyl group or an ethyl group. Further, in the cation of the formula 6 as well, as in the formula 4 above, three of R _{7 to} R ₁₀ are a methyl group and the other one is a trimethyl alkyl group having 4 to 20 carbon atoms or a derivative thereof. Salts of the type quaternary phosphonium cation are preferred for the same reasons as above.

上記化学式１〜３のいずれかに記載の陰イオンを備えた塩は、ビス（トリフルオロメタンスルホニル）イミドリチウム（（ＣＦ₃ＳＯ₂）₂ＮＬｉ）又はビス（トリフルオロメタンスルホニル）イミドカリウム（（ＣＦ₃ＳＯ₂）₂ＮＫ）又は、トリフルオロメタンスルホン酸リチウム（ＣＦ_３ＳＯ_３Ｌｉ）又はトリフルオロメタンスルホン酸カリウム（ＣＦ_３ＳＯ_３Ｋ）又はトリス（トリフルオロメタンスルホニル）メチドリチウム（（ＣＦ_３ＳＯ_２）_３ＣＬｉ）であることが好ましい。これにより可塑化することができ、シームレスベルトの粘弾性の温度依存性が小さくなり電気抵抗値の環境依存性を小さくすることができる。特に（ＣＦ_３ＳＯ_２）_２ＮＬｉ、（ＣＦ_３ＳＯ_２）_２ＮＫ、（ＣＦ_３ＳＯ_２）_３ＣＬｉがこれらの点で優れており好ましい。なお、ビス（トリフルオロメタンスルホニル）イミドカリウムは、ビス（トリフルオロメタンスルホニル）イミドリチウム製造時の中間生成物であり安価に得ることができる。

The salt having an anion according to any one of the above chemical formulas 1 to 3 is bis (trifluoromethanesulfonyl) imide lithium ((CF ₃ SO ₂ ) ₂ NLi) or bis (trifluoromethanesulfonyl) imide potassium ((CF ₃ SO ₂ ) ₂ NK) or lithium trifluoromethanesulfonate (CF ₃ SO ₃ Li) or potassium trifluoromethanesulfonate (CF ₃ SO ₃ K) or tris (trifluoromethanesulfonyl) methidolithium ((CF ₃ SO ₂ ) ₃ CLi ) Is preferable. Thereby, it can plasticize and the temperature dependence of the viscoelasticity of a seamless belt becomes small, and the environmental dependence of an electrical resistance value can be made small. In particular, (CF ₃ SO ₂ ) ₂ NLi, (CF ₃ SO ₂ ) ₂ NK, and (CF ₃ SO ₂ ) ₃ CLi are excellent in these points and are preferable. In addition, bis (trifluoromethanesulfonyl) imide potassium is an intermediate product at the time of manufacture of bis (trifluoromethane sulfonyl) imide lithium, and can be obtained cheaply.

  As the thermoplastic polymer composition having the above polyoxyalkylene structure, polyether block polyamide copolymer resin, polyether ester amide block copolymer resin, polyethylene oxide-polypropylene oxide copolymer resin, polyether block polyolefin resin One or more selected compositions may be mentioned. The composition is preferable from the viewpoint of high affinity and compatibility with the salt, is easily available, and can be reduced in cost. In particular, a polyether block polyamide copolymer resin is preferable because of its excellent conductivity and low Tg.

  It is preferable that the salt provided with the anion in any one of the above chemical formulas 1 to 3 is blended without using a medium composed of a low molecular weight polyether compound having a number average molecular weight of 5000 or less or a low molecular weight polar compound. As a result, the medium does not precipitate together with the ions, and it is possible to prevent the photosensitive member from being contaminated and the toner adhered to the formed conductive belt. In particular, it is possible to prevent toner adhesion, photoconductor contamination, and an increase in electrical resistance when continuously used.

The above salt is excellent in stability and safety, and does not promote polymer degradation due to temperature or impact unlike perchlorate (NaClO ₄ , LiClO ₄ ), so it is blended without using the above medium. It becomes possible. In addition, when using salts containing chlorine and bromine such as perchlorate, there is a risk of corroding and rusting the metal surfaces such as rollers that drive conductive seamless belts, and depending on the incineration conditions after use Dioxin may be generated, which is not preferable.

  A known method can be used as a method of blending a salt without using a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound. For example, after dry blending with a Henschel mixer, a tumbler or the like, a blend of such materials can be melt-mixed with a single or twin screw extruder, a Banbury mixer, a kneader, or the like.

  In addition, a part of the ions generated from the added salt can be converted into a single ion by using an anion adsorbent or the like to stabilize the conductivity or improve the conductivity when added in a small amount. As an anion adsorbent, synthetic hydrotalcite mainly composed of Mg and Al, inorganic ion exchangers such as Mg-Al, Sb, and Ca, and ion sites that fix anions in the chain (co-current). ) Known compounds such as polymers are useful. Specifically, synthetic hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd., trade name Kyoward 2000, Kyoward 1000), anion exchange ion exchange resin (manufactured by Nippon Nensui Co., Ltd., trade name Dyanon DCA11), etc. Is mentioned.

  In the composition for forming the belt, in addition to the above, a polymer component such as a known thermoplastic elastomer or thermoplastic resin can be used alone or in combination, if necessary. Also, calcium carbonate, silica, clay, talc, barium sulfate, as long as they do not cause the release of additives from the belt surface, transfer to contact materials such as photoconductor contamination, and do not adversely affect electrical properties. Contains fillers such as diatomaceous earth, fatty acids such as stearic acid and lauric acid, cottonseed oil, tall oil, asphalt substances, softeners such as paraffin wax, anti-aging agents such as imidazoles, amines, and phenols. Also good.

  Although only the conductive belt of the present invention may be used, a coating layer may be provided on the outer peripheral surface. For example, depending on the purpose, a known material such as urethane, acrylic, rubber latex, etc., in which a fluorine resin is dispersed, is coated by a known method such as electrostatic painting, spray painting, dipping, brush painting, etc. can do. Thus, when used as an intermediate transfer belt of an image forming apparatus, it is possible to easily scrape off toner remaining at the time of transfer, change toner detachability, and control surface energy. The thickness of the coating layer is preferably 1 μm to 20 μm. The coating layer may be a multilayer, and a coating layer may be provided on the inner peripheral surface side of the belt.

  In the present invention, as a method for producing the conductive belt, the salt having the anion according to any one of the chemical formulas 1 to 3 described above with respect to the weight of the thermoplastic polymer composition having a polyoxyalkylene structure. Conductive masterbatch blended at 1% or more and 20% or less is mixed with a fluorinated thermoplastic polymer, and this melt-kneaded product is extruded from an extruder equipped with an annular die, and seamlessly along the sizing mold. A method of manufacturing a conductive belt formed into a belt shape is provided.

  The salt provided with the anion according to any one of the chemical formulas 1 to 3 is kneaded in advance into the thermoplastic polymer composition having the polyoxyalkylene structure to form a conductive masterbatch, whereby the salt Because it is present in the plastic polymer composition, it is not easily affected by the environment such as temperature and humidity, and it is possible to reduce the variation in electrical resistance and the environmental dependency of the resistance value, as well as to reduce the resistance increase during continuous energization. I can do it. By kneading and extruding this conductive masterbatch with a fluorinated thermoplastic polymer, etc., the above salt, together with the thermoplastic polymer composition having a polyoxyalkylene structure, can be fluorinated with a desired concentration. A conductive belt that is efficiently and uniformly dispersed in the polymer and stably realizes the above-described electrical characteristics can be easily obtained.

  In the conductive master batch, if the amount of the salt is less than 1% by weight, it is difficult to obtain the effect of the salt, and the target salt concentration is deviated, or the salt concentration is not uniform in the master batch. May occur. On the other hand, when it exceeds 20% by weight, it becomes difficult to uniformly disperse in the thermoplastic polymer composition. The amount of the salt is preferably 2 to 15% by weight, more preferably 5 to 10% by weight. When using a conductive masterbatch, the desired amount of salt can be uniformly dispersed compared to the case where it is blended in the whole polymer, and the resistance value can be easily adjusted. Can be obtained.

  When the master batch is used, it is possible to prevent the salt from adhering to the wall surface of the hopper, to improve work efficiency, and to prevent the moisture content in the material and the surface state from being changed due to moisture absorption during storage. In addition to the above-mentioned salt, various fillers and processing aids can be added to the master batch as necessary, whereby the processability can be further improved.

  In addition, if necessary, a thermoplastic polymer composition having a polyoxyalkylene structure not containing a salt having an anion according to any one of chemical formulas 1 to 3 is mixed with a conductive masterbatch and a fluorine-based thermoplastic polymer. You may mix with coalescence.

As a method for forming a conductive belt from the melt-kneaded material to be the belt resin composition, it is most preferable to extrude from the annular die in the vertical direction and to form a seamless belt along a sizing die.
The melt coming out of the die lip is not affected by gravity by being pushed out in the vertical direction, the residual strain is reduced, and it is guided to the sizing die while maintaining the cylindrical state, thereby improving the dimensional accuracy. In particular, the direction of extrusion is preferably vertically downward. Further, the kneaded material melted by the extruder can be guided to an annular die, extruded from the die lip, and contact-cooled and cured in a sizing die provided downstream from the die lip to be formed into a belt shape. The sized continuous cylindrical molded product is further cut by a cutting device provided downstream, and a belt having a predetermined width can be obtained. According to the extrusion molding, even a large-diameter thin-walled belt having a diameter of 168 mm, a wall thickness of 250 μm, and a width of 400 mm can be easily molded.

In any of the extruder for kneading the mixture, the kneader, and the extruder for molding, light metal, titanium, and boron are in contact with the fluorine-based thermoplastic polymer at a temperature equal to or higher than the melting point of the fluorine-based thermoplastic polymer. Aluminum, nitrided boron alloy is not used.
If the fluorine-based thermoplastic polymer comes into contact with a metal such as titanium in a molten state, decomposition of the fluorine-based thermoplastic polymer may be promoted and a harmful gas such as hydrogen fluoride may be generated. Decomposition can be prevented.

  In addition, you may provide the surface layer which uses only the thermoplastic polymer composition which has the said polyoxyalkylene structure, and the fluorine-type thermoplastic polymer which does not contain a salt as a main component polymer as a surface layer of the said belt. Thereby, the transfer of the salt to the photoreceptor or the like can be further prevented. Such a surface layer can be formed by two-layer extrusion.

  The mixing of the compounding materials may be performed by a conventional method using a single screw extruder, a twin screw extruder, a closed kneader, an open roll, a kneader, or the like, but a twin screw extruder is particularly preferable because of high kneading efficiency. The conductive belt of the present invention can be formed by injection molding or the like in addition to extrusion molding. Further, a cylindrical belt may be formed by connecting sheets formed into a sheet shape.

  The thickness of the belt to be extruded is 50 μm to 500 μm. The thickness can be changed by adjusting the gap of the die lip at the time of extrusion molding, and by adjusting the discharge amount of the resin and the take-up speed of the belt. If the thickness is less than 50 μm, the film tends to be stretched, and a shift occurs when an image is formed by superimposing multicolor toners in a color image forming apparatus. If it is thicker than 500 μm, the bending rigidity of the belt becomes high and the belt cannot be suspended on the drive shaft.

The present invention further provides an image forming apparatus comprising the conductive belt of the present invention or the conductive belt manufactured by the manufacturing method of the present invention.
The image forming apparatus includes the conductive belt of the present invention, so that a uniform image can be obtained, and since the resistance value is less dependent on the environment, it is not necessary to use a large power source to cover the resistance value change. The power consumption of the entire apparatus can be reduced. Further, it is not necessary to control the applied voltage, and the apparatus can be made simpler.

  As is clear from the above explanation, according to the present invention, the fluorine-based thermoplastic polymer, the thermoplastic polymer composition having a polyoxyalkylene structure, and the anion according to any one of the chemical formulas 1 to 3 are used. The provided salt is contained in the above specified weights. For this reason, there is no problem of bleed, bloom, photoconductor contamination, and migration contamination, and the belt can have a small resistance variation in the surface and a very small resistance dependency on the environment. . Moreover, since the main component is a fluorine-based thermoplastic polymer, flame retardancy can be imparted without affecting the electrical characteristics.

  In addition, according to the production method of the present invention, the salt provided with the anion according to any one of chemical formulas 1 to 3 is effectively incorporated into the thermoplastic polymer composition having a polyoxyalkylene structure. It is possible to reduce the environmental dependency of the resistance value and easily manufacture a conductive belt having a good extruded skin.

  As described above, the conductive belt of the present invention has a very small environmental dependency. Therefore, in an image forming apparatus such as a copying machine, a facsimile machine, and a printer, the conductive belt is stable and good without being affected by temperature, humidity, and the like. Characteristics can be realized. For example, when used as an intermediate transfer belt, good transfer performance can be obtained over a long period of time without causing transfer deviation or transfer failure.

  In addition, since it is not necessary to use a large power source to cover the resistance value change, the power consumption of the entire image forming apparatus can be reduced, and environmental testing during development can be reduced. Can be suppressed. In addition, it can also be used for a conveyor belt, a developing belt, a fixing belt, a substrate belt of a belt-like photoreceptor, and the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a form in which the conductive belt according to the first embodiment of the present invention is used as an intermediate transfer belt 10.

  As an image forming apparatus provided with the conductive belt of the present invention, as shown in FIG. 1, there is a structure for a color printer using the conductive belt of the present invention as an intermediate transfer belt 10. The color printer as an image forming apparatus according to the present invention includes an intermediate transfer belt 10, a charging roller 11, a photoreceptor 12, transfer rollers 13a and 13b, a fixing roller 14, and four color toners 15 (15a, 15b, 15c, and 15d). A mirror 16 is provided.

  When an image is formed by this color image forming apparatus, first, the photoconductor 12 rotates in the direction of the arrow in the figure, and after the photoconductor 12 is charged by the charging roller 11, the laser 17 is passed through the mirror 16. Is exposed to the non-image portion of the photoconductor 12 and is neutralized, and the portion corresponding to the image portion is charged. Next, the toner 15a is supplied onto the photoreceptor 12, and the toner 15a adheres to the charged image line portion to form a first color image. This toner image is transferred onto the intermediate transfer belt 10 by applying an electric field to the primary transfer roller 13a. Similarly, the images of the respective colors of the toners 15b to 15d formed on the photosensitive member 12 are transferred onto the intermediate transfer belt 10, and the full color image composed of the four colors of toner 15 (15a to 15d) is formed on the intermediate transfer belt 10. Is once formed. The full-color image is transferred onto a transfer target (usually paper) 18 by applying an electric field to the secondary transfer roller 13b, and passes through the fixing roller 14 heated to a predetermined temperature, thereby transferring the transfer target 18. Is fixed to the surface. When performing double-sided printing, the transfer target 18 that has passed through the fixing roller 14 is reversed inside the printer, and the image forming process is repeated to form an image on the back side again.

  The intermediate transfer belt 10 which is a conductive belt of the present invention has a glass transition temperature having 100 parts by weight of a polyvinylidene fluoride having a glass transition temperature Tg of −42 ° C. which is a fluorine-based thermoplastic polymer and a polyoxyalkylene structure. 30 parts by weight of a polyethylene oxide block nylon 12 copolymer, which is a thermoplastic polymer composition having a Tg of −55 ° C., and 1 part of bis (trifluoromethanesulfonyl) imide lithium, which is a salt having an anion described in Chemical Formula 1. It consists of only one conductive layer formed of a belt resin composition containing 5 parts by weight. Bis (trifluoromethanesulfonyl) imide lithium is 1.15 parts by weight with respect to 100 parts by weight of the total polymer, and the fluorine-based thermoplastic resin is 76% of the total weight.

Hereinafter, the manufacturing method of the electroconductive belt of this invention is explained in full detail.
First, a conductive master batch in which 5% by weight of bis (trifluoromethanesulfonyl) imide lithium ((CF ₃ SO ₂ ) ₂ NLi) is blended with a polyethylene oxide block nylon 12 copolymer, polyvinylidene fluoride, Are mixed with a twin-screw extruder so as to achieve the above blending ratio, and the mixture is melt-kneaded to prepare a resin composition for a belt.

  FIG. 2 shows a belt manufacturing apparatus 20. The belt manufacturing apparatus 20 includes a hopper 21 for charging a material made of a resin composition for a belt, a belt molding extruder 22 for melting and extruding the charged material, a central axis of the belt molding extruder 22 and a center of the die. A crosshead die 23 having a right angle shaft and an annular die structure, a gear pump 24 arranged between the belt molding extruder 22 and the crosshead die 23 and adjusting the amount of extrusion, and the extruded annular object B are arranged on the inner circumference. Inside sizing 25 which is a sizing mold for shaping from the surface side, take-up machine 26 for taking up the shaped annular object B in the vertical direction, and automatic cutting machine for cutting the continuously formed annular object B to a predetermined length 27. The cross head die 23 is configured to push the melt vertically downward from the die lip 23a of the annular die.

  The belt resin composition is introduced from the hopper 21 of the belt molding extruder 22 and melted at 180 ° C. to 250 ° C., and the melt is fed into the crosshead die 23 while adjusting the extrusion amount by the gear pump 24. The melt is pushed vertically downward from the die lip 23 a of the annular die of the crosshead die 23. The annular material B pushed out from the die lip 23a is cooled along the inside sizing 25 at 70 ° C. to 100 ° C., shaped into a belt shape, taken down vertically by the take-up machine 26, and taken to a predetermined length by the automatic cutting machine 27. A conductive belt made of a single conductive layer is manufactured. The conductive belt is used as the intermediate transfer belt 10.

The conductive belt has a relationship between a volume resistivity R _LL in a low temperature and low humidity environment (10 ° C., relative humidity 15%) and a volume resistivity R _HH in a high temperature and high humidity environment (32.5 ° C., relative humidity 90%). Is log ₁₀ R _LL -log ₁₀ R _HH = 0.9. Further, bis (trifluoromethanesulfonyl) imide lithium is blended without a medium composed of a low molecular weight polyether compound having a number average molecular weight of 5000 or less or a low molecular weight polar compound.

  The intermediate transfer belt 10 is a conductive belt excellent in practicality that is free from contamination of the photoreceptor, has a small variation in resistance value, and has a very small environmental dependency of the resistance value. Further, the flame resistance is imparted to the belt without affecting the volume resistivity, and the extruded skin is also smooth. Therefore, the conductive belt of the present invention can obtain a uniform image without being restricted by the use state even when the belt is placed in a high voltage and high temperature environment in the image forming apparatus.

  In addition to the above-described embodiment, it can also be used as a conveyance belt, a transfer belt, a fixing belt, a developing belt, a photoreceptor substrate belt, or the like of an image forming apparatus such as a copying machine, a facsimile machine, or a printer. In particular, when a white belt is used, toner adhesion can be easily visually checked, so that it is suitable for evaluation of cleaning performance and can be suitably used as an intermediate transfer belt.

  In addition, as long as it has the anion in any one of Chemical formulas 1-3, it is not limited to the said salt, You may change the kind etc. of a cation. The thermoplastic polymer composition having a polyoxyalkylene structure and the fluorine-based thermoplastic polymer can also be appropriately changed. In addition to the manufacturing method by extrusion molding, it is also possible to mold by injection molding, etc., not only by seamless extrusion molding, but also as a cylindrical belt by connecting the vicinity of the end surface of the sheet shape It can also be manufactured. Moreover, it can also shape | mold without using a masterbatch.

  Examples of the conductive belt of the present invention and comparative examples will be described in detail below.

(Example 1)
The concentration of the salt having an anion according to any one of Chemical Formulas 1 to 3 with respect to the thermoplastic polymer composition having a polyoxyalkylene structure is 5 wt. %, And dry blended with a tumbler, and then melt-kneaded in a twin screw extruder adjusted to 200 ° C. to prepare a conductive master batch. The temperature of the conductive masterbatch immediately after extrusion was 210 ° C to 220 ° C.

  Bis (trifluoromethanesulfonyl) imidolithium is used as the salt, and polyether block polyamide copolymer resin (Irgastat P16 (polyethylene oxide block nylon 12 copolymer, Tg = −55 ° C.)) is used as the thermoplastic polymer composition. Ciba Specialty Chemicals Co., Ltd.) was used.

  This conductive masterbatch and fluorine-based thermoplastic polymer were dry blended in the same tumbler at a weight ratio of 31.5: 100, and this was put into the hopper of a twin screw extruder, and set at 200 ° C. The resin composition for belts was produced by kneading. The resin temperature immediately after extrusion at this time was 205 ° C. to 225 ° C. The fluorine-based thermoplastic resin was 76% of the total weight, and the salt was 1.15 parts by weight with respect to 100 parts by weight of the total polymer.

  As the fluorine-based thermoplastic polymer, a fluorine-based thermoplastic resin (polyvinylidene fluoride (PVDF) (SOLEF 1008 (Tg = −42 ° C.): manufactured by Solvay Solexis)) was used.

  The belt resin composition is put into a hopper of a belt molding extruder, the belt molding extruder is operated, and the molten resin is vertically moved from an annular die having an inner diameter of 185 mm and a gap of 0.5 mm at a die temperature of 220 ° C. Extruded, solidified by conforming to an inside sizing mold having an outer diameter of 168 mm, pulled downward at a take-up speed of 1 m / min, and continuously cut to a width of 400 mm with a fixed-size cutting device to obtain a seamless belt continuously. The obtained belt had a belt inner diameter = 167.5 mm, an average wall thickness = 250 μm, and a width = 400 mm.

  In the twin screw extruder and belt molding extruder used, the area where the melt of the fluorine-based thermoplastic resin comes into contact at a temperature equal to or higher than the melting point of the fluorine-based thermoplastic polymer (in the case of the twin-screw extruder: “screw” (Segment shafts, barrels, caps), belt molding extruders: “screws, barrels, crosshead dies, gear pumps, inside sizing, take-up machines, annular dies, die lips, etc.”) are all light metals, titanium Boron, aluminum, and nitriding boron alloy were not used.

(Example 2)
The conductive masterbatch and the fluorine-based thermoplastic resin were blended at a weight ratio of 10.5: 100. The fluorine-based thermoplastic resin was 90% of the total weight, and the salt was 0.45 parts by weight with respect to 100 parts by weight of the total polymer. Others were the same as in Example 1.
(Example 3)
The conductive masterbatch and the fluorine-based thermoplastic resin were blended at a weight ratio of 52.5: 100. The fluorine-based thermoplastic resin was 66% of the total weight, and the salt was 1.67 parts by weight with respect to 100 parts by weight of the total polymer. Others were the same as in Example 1.
Example 4
The salt was potassium bis (trifluoromethanesulfonyl) imide. Others were the same as in Example 1.
(Example 5)
The fluorine-based thermoplastic resin was polyvinylidene fluoride (PVDF) (SOLEF 1006 (Tg = −42 ° C., manufactured by Solvay Solexis)). The thermoplastic polymer composition having a polyoxyalkylene structure was made into perestert NC6321 (manufactured by Sanyo Chemical Industries, Tg = −42 ° C.), which is a polyether ester amide block copolymer. Others were the same as in Example 1.
(Example 6)
A thermoplastic polymer composition having a polyoxyalkylene structure was converted into an ethylene oxide-propylene oxide copolymer (ethylene oxide: propylene oxide = 90: 10 (molar ratio)) ZSN8100 (manufactured by Nippon Zeon Co., Ltd., Tg = −62 ° C.). Others were the same as in Example 5.
(Example 7)
Synthetic hydrotalcite (Kyoward 2000, manufactured by Kyowa Chemical Industry Co., Ltd.) was blended in the conductive masterbatch as an anion adsorbent. Anion adsorbent: bis (trifluoromethanesulfonyl) imide lithium = 1: 5. Others were the same as in Example 2.
(Example 8)
The salt was lithium trifluoromethanesulfonate, which is a salt having an anion described in Chemical Formula 2. Others were the same as in Example 1.
Example 9
The salt was tris (trifluoromethanesulfonyl) methide lithium which is a salt having an anion described in Chemical Formula 3. Others were the same as in Example 1. Tris (trifluoromethanesulfonyl) methide lithium used was synthesized by a known method described in US Pat. No. 5,554,664, Japanese Patent Application Laid-Open No. 2000-219692, Japanese Patent Application Laid-Open No. 2000-226392, and the like.
(Example 10)
The salt was 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion described in Chemical Formula 1 and a cation described in Chemical Formula 5. Others were the same as in Example 1.
(Example 11)
The salt was hexyltrimethylammonium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion described in Chemical Formula 1 and a cation described in Chemical Formula 4. Others were the same as in Example 1.

(Comparative Example 1)
A belt was produced in the same manner as in Example 1 except that the resin composition for the belt was only the above-mentioned fluorine-based thermoplastic resin (SOLEF1008), and the thermoplastic polymer composition having a salt / polyoxyalkylene structure was not blended. .
(Comparative Example 2)
A belt was prepared in the same manner as in Comparative Example 1 without adding a salt as [fluorinated thermoplastic resin (SOLEF1008): polyether block polyamide copolymer resin (Irgastat P16) = 100: 30].
(Comparative Example 3)
A belt was prepared in the same manner as in Comparative Example 1 without adding a salt as [fluorinated thermoplastic resin (SOLEF1008): polyether block polyamide copolymer resin (Irgastat P16) = 100: 50].
(Comparative Example 4)
A belt was prepared in the same manner as in Comparative Example 1 without adding salt as [fluorinated thermoplastic resin (SOLEF1006): polyetheretheramide block copolymer (Perestat NC6321) = 100: 30].
(Comparative Example 5)
A belt was prepared in the same manner as in Comparative Example 1 without adding a salt as [fluorinated thermoplastic resin (SOLEF1006): ethylene oxide-propylene oxide copolymer (ZSN8100) = 100: 30].
(Comparative Example 6)
The thermoplastic polymer composition having a polyoxyalkylene structure was made into perestert NC7530 (manufactured by Sanyo Chemical Industries, Tg = −20 ° C.) which is a polyether ester amide block copolymer resin.
A belt was prepared in the same manner as in Comparative Example 1 without adding a salt as [fluorinated thermoplastic resin (SOLEF1006): polyetheresteramide block copolymer resin (Pelestat NC7530) = 100: 50].
(Comparative Example 7)
As a thermoplastic polymer composition having a polyoxyalkylene structure, a material comprising polyethylene oxide block nylon 12 copolymer: nylon 12 = 1: 1 containing sodium perchlorate monohydrate (Irgastat P18 (Ciba・ Specialty Chemicals Co., Ltd.) [Fluorine-based thermoplastic resin (SOLEF1006): Irgastat P18 = 100: 50] In addition to NaClO ₄ · H ₂ O salt already contained in Irgastat P18 No salt was added and a belt was prepared in the same manner as in Comparative Example 1.

  Tables 1 and 2 show the belt performance (volume resistivity, volume resistivity environment dependency, in-plane unevenness, photoconductor contamination test, image formation test, tear strength) of the above examples and comparative examples. Each performance was measured by the method described later.

(Volume resistivity, environment dependence)
For the conductive belt produced as described above, a digital ultra-high resistance microammeter R-8340A manufactured by Advantest Corporation was used at room temperature and normal humidity conditions (NN condition, R _{NN) at} 23 ° C. and 55% relative humidity. ) Measurement was performed under a constant temperature and humidity condition of a low temperature and low humidity condition (LL condition, R _LL ) of 10% relative humidity 15% (LL condition, R _LL ), and a high temperature and high humidity condition (HH condition, R _HH ) of 32.5 ° C. relative humidity 90%. The measurement method was in accordance with the volume resistivity measurement method described in JIS K6911, and the applied voltage during measurement was 500V. log ₁₀ R _NN is preferably 11.0 or less, and log ₁₀ R _LL is preferably 12.0 or less. Preferably _{Δlog 10 R = log 10 R LL} -log 10 R HH ≦ 1.8 indicating the environmental dependency, and more preferably 1.6 or less.

(In-plane unevenness)
Under 23 ° C. and 55% relative humidity (NN conditions), with an applied voltage of 500 V, the belt was measured in a total of 20 points in the circumferential direction of 4 points × longitudinal direction of 5 points, and the maximum value was divided by the minimum value. The value was calculated to be in-plane unevenness. The in-plane unevenness is preferably 1.2 or less.

(Photoconductor contamination test)
The obtained section of the conductive belt was brought into pressure contact with a photoreceptor set in a cartridge (product code CT350035) used in a laser beam printer DocuPrint 180 manufactured by Fuji Xerox Co., Ltd. Stored under conditions for 2 weeks.
Thereafter, the belt section was removed from the photoconductor, halftone printing was performed with the printer using the photoconductor, and whether or not the printed material was stained was examined according to the following criteria.
○: No contamination as long as the printed product is visually observed. △: Mild contamination (contamination with no problem in use that can be removed to the extent that it cannot be seen by visual impression within 5 sheets)
×: Severe contamination (contamination that reveals abnormalities by visual inspection of printed matter even when 5 or more sheets are imprinted)

(Tear strength)
JIS K7128-3 Plastics-Test method for tear strength of films and sheets-Part 3: Tests were carried out in accordance with the description of the right angle tear method. Among these, the test piece was sampled in the lateral direction (when tearing at right angles to the extrusion direction) and tested, the result [N / mm] is shown. If this strength is less than 100 N / mm, there is a possibility of problems in durability when used as a conductive belt (particularly, an intermediate transfer belt), such as the possibility of tearing or cracking of the end face.

(Image output test)
Each belt was mounted as an intermediate transfer belt of a full-color electrophotographic apparatus (Seiko Epson, Intercolor LP-8300C), an image output test was performed, and the transfer performance was evaluated.
◯: Good image x: Image defect (In the comparative example, the x value indicated that the resistance value was too high, so a high voltage was required at the time of transfer and the image was also deteriorated.)

  In Examples 1 to 7, a fluorine-based thermoplastic polymer, a thermoplastic polymer composition having a polyoxyalkylene structure, and a salt having an anion according to any one of Chemical Formulas 1 to 3 are used. Blended within the specified range. For this reason, the volume resistivity at normal temperature and normal humidity and low temperature and low humidity is in an appropriate range, and the environmental dependency of the volume resistivity is very small. Further, the in-plane unevenness was small and the resistance variation was small, and the photoreceptor contamination was not problematic in use, and the results of the image output test and tear strength were also good.

  On the other hand, in Comparative Example 1, since the belt was made of only the fluorine-based thermoplastic resin, the volume resistivity was very high and the environmental dependency thereof was large, so that the image output test was unsuitable. In Comparative Examples 2 to 6, since the salt provided with the anion described in any one of Chemical Formulas 1 to 3 was not blended, the volume resistivity was high and the imaging test was unsuitable. Moreover, although the comparative example 7 used the commercially available antistatic agent containing perchlorate instead of the salt provided with any anion of Chemical formula 1-3, the environmental dependence of volume resistivity is large. In addition, the tear strength is low, which is not suitable. Photoreceptor contamination was not practical, but the results were somewhat poor.

FIG. 2 is a schematic front view of a color image forming apparatus including a conductive belt. It is the schematic of the manufacturing apparatus of an electroconductive belt.

Explanation of symbols

10 Intermediate Transfer Belt 22 Belt Molding Extruder 23 Cross Die Head 25 Inside Sizing

Claims (11)

A thermoplastic polymer composition having a polyoxyalkylene structure and a salt having an anion according to any one of the following chemical formulas 1 to 3 are blended in a fluorine-based thermoplastic polymer, A conductive material having a conductive layer, characterized in that the coalescence is formed from an ionically conductive polymer, and the salt is blended in an amount of 0.01 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the total polymer. belt.

(Wherein X ₁ , X ₂ and X ₃ are functional groups having 1 to 8 carbon atoms, including C, —F and —SO ₂ —). The fluorine-based thermoplastic polymer is 98 parts by weight or less and 40 parts by weight or more with respect to 100 parts by weight of the total polymer, and the salt is 0.1% to 20% by weight of the thermoplastic polymer composition having the polyoxyalkylene structure. % Or less,
The conductive belt according to claim 1, wherein the thermoplastic polymer composition having a polyoxyalkylene structure has a glass transition temperature Tg of -40 ° C or lower. The conductive layer is a low-temperature low-humidity environment (10 ° C., 15% relative humidity) and a volume resistivity R _LL at high temperature and high humidity environment (32.5 ° C., 90% relative humidity) the volume resistivity R _HH in the, log ₁₀ The conductive belt according to claim 1, satisfying a relationship of R _LL −log ₁₀ R _HH ≦ 1.8. In the above chemical formulas 1 to 3, X ₁ − is C _n1 H _m1 F _{(2n1-m1 + 1)} —SO ₂ —, and X ₂ − is C _n2 H _m2 F _{(2n2-m2 + 1)} —SO ₂ —. And X ₃ − is C _n3 H _m3 F _{(2n3-m3 + 1)} (where n1, n2, and n3 are integers of 1 or more, and m1, m2, and m3 are integers of 0 or more). The conductive belt according to any one of the above. The cation constituting the salt paired with the anion according to any one of the above chemical formulas 1 to 3 is an alkali metal containing lithium or potassium, a group 2A element, a transition metal, a cation of an amphoteric metal, or The conductive belt according to any one of claims 1 to 4, which is a cation according to any one of the following chemical formulas 4 to 6.

(R _{1 to} R ₁₀ are each an alkyl group having 1 to 20 carbon atoms or a derivative thereof) The salt having an anion according to any one of the above chemical formulas 1 to 3 is bis (trifluoromethanesulfonyl) imide lithium or bis (trifluoromethanesulfonyl) imide potassium, lithium trifluoromethanesulfonate, potassium trifluoromethanesulfonate, or The conductive belt according to any one of claims 1 to 5, which is tris (trifluoromethanesulfonyl) methide lithium. The thermoplastic polymer composition having the polyoxyalkylene structure comprises a polyether block polyamide copolymer resin, a polyether ester amide block copolymer resin, a polyethylene oxide-polypropylene oxide copolymer resin, and a polyether block polyolefin resin. The conductive belt according to claim 1, wherein the conductive belt is one or more selected compositions. The salt provided with the anion according to Chemical Formula 1 is blended without using a medium composed of a low molecular weight polyether compound having a number average molecular weight of 5,000 or less or a low molecular weight polar compound. The conductive belt according to any one of the above. Conductive master in which a salt having an anion according to any one of the following chemical formulas 1 to 3 is blended in an amount of 1% to 20% with respect to the weight of the thermoplastic polymer composition having a polyoxyalkylene structure. Production of a conductive belt in which a batch and a fluorinated thermoplastic polymer are mixed, and this melt-kneaded product is extruded from an extruder equipped with an annular die and formed into a seamless belt shape along a sizing die Method.

(Wherein X ₁ , X ₂ and X ₃ are functional groups having 1 to 8 carbon atoms, including C, —F and —SO ₂ —). Any of the extruder for kneading the mixture, the kneading machine, and the extrusion molding machine may be made of a light metal, titanium, boron, a portion that comes into contact with the fluorine-based thermoplastic polymer at a temperature equal to or higher than the melting point of the fluorine-based thermoplastic polymer, The method for producing a conductive belt according to claim 9, wherein aluminum or nitrided boron alloy is not used. An image forming apparatus comprising the conductive belt according to claim 1, or the conductive belt manufactured by the manufacturing method according to claim 9 or 10.

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