JP2009192603A - Conductive endless belt and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive endless belt which, without adding a carbodiimide compound thereto, satisfies both flexibility and rigidity, has good breaking resistance and does not cause the problem of image shift due to undulation and waving, and to provide an image forming apparatus using the same. <P>SOLUTION: The conductive endless belt for use in an image forming apparatus contains a polyester-based thermoplastic elastomer and a polyester-based thermoplastic resin. The conductive endless belt has a monolayer structure containing the polyester-based thermoplastic elastomer in an amount larger than the amount of the polyester-based thermoplastic resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developer on the surface of an image forming body such as a latent image holding body holding an electrostatic latent image on the surface in an electrostatic recording process in an electrophotographic apparatus such as a copying machine or a color laser printer, or an electrostatic recording apparatus. The present invention relates to a conductive endless belt (hereinafter, also simply referred to as “belt”) used when transferring a toner image formed by supplying toner to a recording medium such as paper, and an image forming apparatus using the same.

  Conventionally, in an electrostatic recording process in a copying machine, a printer, etc., first, the surface of a photosensitive member (latent image holding member) is uniformly charged, and an image is projected onto the photosensitive member from an optical system and exposed to light. An electrostatic latent image is formed by erasing the charged portion, and then toner is supplied to the electrostatic latent image to form a toner image by electrostatic adhesion of the toner, which is formed on paper, OHP, photographic paper For example, a method of printing by transferring to a recording medium such as the above is employed.

  In this case, color printers and color copiers basically print according to the above process, but in the case of color printing, the color tone is reproduced using toners of four colors, magenta, yellow, cyan, and black. Therefore, a process for obtaining a necessary color tone by superimposing these toners at a predetermined ratio is required, and several methods have been proposed for performing this process.

  First, as in the case of monochrome printing, when the electrostatic latent image is visualized by supplying toner onto the photosensitive member, the four colors of magenta, yellow, cyan, and black are sequentially added. There is a multi-development system in which development is performed by superimposing and a color toner image is formed on the photoreceptor. According to this method, it is possible to configure the apparatus relatively compactly, but this method has a problem in that it is very difficult to control gradation and high image quality cannot be obtained.

  Second, four photosensitive drums are provided, and the latent images on each drum are developed with magenta, yellow, cyan, and black toners, respectively, so that a magenta toner image, a yellow toner image, a cyan toner image, and a black toner image are obtained. By forming four toner images of the toner image, arranging the photosensitive drums on which these toner images are formed in a line, sequentially transferring the toner images onto a recording medium such as paper, and superimposing them on the recording medium, a color image is formed. There is a tandem method to reproduce. Although this method can obtain a good image, the four photosensitive drums, the charging mechanism and the developing mechanism provided for each photosensitive drum are arranged in a line, and the apparatus becomes large and expensive. It becomes.

  FIG. 2 shows a configuration example of the printing unit of the tandem image forming apparatus. A printing unit composed of the photosensitive drum 1, the charging roll 2, the developing roll 3, the developing blade 4, the toner supply roll 5, and the cleaning blade 6 corresponds to each toner of yellow Y, magenta M, cyan C, and black B 4 The toner images are sequentially transferred onto a sheet that is circulated by a driving roller (driving member) 9 and conveyed by a transfer conveying belt 10 to form a color image. Charging and discharging of the transfer / conveying belt are performed by the charging roll 7 and the discharging roll 8, respectively. Further, a suction roller (not shown) is used for charging the paper for sucking the paper onto the belt. Owing to these measures, generation of ozone can be suppressed. The suction roller places the paper on the transfer conveyance belt from the conveyance path and performs electrostatic adsorption on the transfer conveyance belt. Further, the sheet separation after the transfer can be performed only by the curvature separation by lowering the transfer voltage to weaken the adsorption force between the sheet and the transfer conveyance belt.

  As materials for the transfer / conveyance belt 10, there are a resistor and a dielectric, each having advantages and disadvantages. Since the resistor belt can hold charges for a short time, when it is used for tandem transfer, there is little charge injection during transfer, and the voltage rise is relatively small even during continuous transfer of four colors. In addition, when it is repeatedly used for the transfer of the next sheet, the electric charge is released, and no electrical reset is required. However, since the resistance value changes due to environmental fluctuations, there are disadvantages such as affecting transfer efficiency and being easily influenced by the thickness and width of the paper.

  On the other hand, in the case of a dielectric belt, there is no spontaneous release of injected charge, and both charge injection and discharge must be electrically controlled. However, since the charge is stably held, the sheet can be adsorbed reliably and can be conveyed with high accuracy. Since the dielectric constant is less dependent on temperature and humidity, the transfer process is relatively stable to the environment. The drawback is that the transfer voltage increases because charges are accumulated on the belt each time the transfer is repeated.

  Thirdly, a recording medium such as paper is wound around a transfer drum, and this is rotated four times, and magenta, yellow, cyan, and black on the photosensitive member are sequentially transferred to the recording medium every rotation to reproduce a color image. There is also a method. According to this method, a relatively high image quality can be obtained. However, when the recording medium is a cardboard such as a postcard, it is difficult to wind the recording medium around the transfer drum, and the type of the recording medium is limited. There is.

  A system in which good image quality is obtained with respect to the multiple development system, tandem system and transfer drum system, the apparatus is not particularly large, and the type of recording medium is not particularly limited. As an example, an intermediate transfer method has been proposed.

  That is, in this intermediate transfer system, an intermediate transfer member composed of a drum or a belt for temporarily transferring and holding the toner image on the photosensitive member is provided, and a magenta toner image, a yellow toner image, and a cyan toner are provided around the intermediate transfer member. An image and four photoconductors on which a black toner image is formed are arranged, and four color toner images are sequentially transferred onto the intermediate transfer member, thereby forming a color image on the intermediate transfer member. The image is transferred onto a recording medium such as paper. Therefore, since the gradation is adjusted by superimposing the four color toner images, it is possible to obtain high image quality, and it is not necessary to arrange the photoconductors in a row as in the tandem method, so that the apparatus can be used. There is no particular increase in size, and there is no need to wrap the recording medium around the drum, so the type of recording medium is not limited.

  As an apparatus for forming a color image by the intermediate transfer method, an image forming apparatus using an endless belt-shaped intermediate transfer member as an intermediate transfer member is illustrated in FIG.

  In FIG. 3, reference numeral 11 denotes a drum-shaped photoconductor, which rotates in the direction of the arrow in the figure. The photosensitive member 11 is charged by the primary charger 12, and then the charged portion of the exposed portion is erased by image exposure 13, and an electrostatic latent image corresponding to the first color component is formed on the photosensitive member 11. The electrostatic latent image is developed with the first color magenta toner M by the developing device 41, and a first color magenta toner image is formed on the photoreceptor 11. Next, the toner image is circulated and driven by a driving roller (driving member) 30 and transferred to the intermediate transfer member 20 that circulates and rotates while contacting the photoreceptor 11. In this case, transfer from the photoconductor 11 to the intermediate transfer member 20 is performed by a primary transfer bias applied from the power source 61 to the intermediate transfer member 20 at the nip portion between the photoconductor 11 and the intermediate transfer member 20. After the first color magenta toner image is transferred to the intermediate transfer member 20, the surface of the photoconductor 11 is cleaned by the cleaning device 14, and the development transfer operation for the first rotation of the photoconductor 11 is completed. Thereafter, the photoconductor rotates three times, and the second color cyan toner image, the third color yellow toner image, and the fourth color black toner image are sequentially used by the developing units 42 to 44 for each turn. The toner image is formed on the intermediate transfer member 20 and is superimposed and transferred to the intermediate transfer member 20 every round, so that a composite color toner image corresponding to the target color image is formed on the intermediate transfer member 20. In the apparatus of FIG. 3, the developing devices 41 to 44 are sequentially replaced with each rotation of the photoreceptor 11 so that development with magenta toner M, cyan toner C, yellow toner Y, and black toner B is sequentially performed. It has become.

  Next, the transfer roller 25 contacts the intermediate transfer member 20 on which the composite color toner image is formed, and a recording medium 26 such as paper is fed from the paper feed cassette 19 to the nip portion. At the same time, a secondary transfer bias is applied from the power source 29 to the transfer roller 25, and the composite color toner image is transferred from the intermediate transfer member 20 onto the recording medium 26 and heated and fixed to form a final image. After the composite color toner image is transferred to the recording medium 26, the transfer residual toner on the surface is removed by the cleaning device 35, and the intermediate transfer member 20 returns to the initial state to prepare for the next image formation.

  There is also an intermediate transfer method that combines a tandem method and an intermediate transfer method. FIG. 4 illustrates an intermediate transfer type image forming apparatus that forms a color image using an endless belt-shaped intermediate transfer member.

  In the illustrated apparatus, a first developing unit 54 a to a fourth developing unit 54 d that develop the electrostatic latent images on the photosensitive drums 52 a to 52 d with yellow, magenta, cyan, and black, respectively, along the intermediate transfer member 50. The intermediate transfer members 50 are sequentially arranged, and the intermediate transfer members 50 are circulated and driven in the direction of the arrows in the drawing to sequentially transfer the four color toner images formed on the photosensitive drums 52a to 52d of the developing units 54a to 54d. As a result, a color toner image is formed on the intermediate transfer member 50, and the toner image is transferred onto a recording medium 53 such as paper to perform printout. Here, in any of the above-described apparatuses, the arrangement order of the toners used for development is not particularly limited, and can be arbitrarily selected.

  In the figure, reference numeral 55 denotes a driving roller or tension roller for circulatingly driving the intermediate transfer member 50, reference numeral 56 denotes a recording medium feeding roller, reference numeral 57 denotes a recording medium feeding apparatus, and reference numeral 58 denotes a recording medium. 1 shows a fixing device for fixing an image by heating or the like. Reference numeral 59 denotes a power supply device (voltage applying means) for applying a voltage to the intermediate transfer member 50. The power supply device 59 transfers a toner image from the photosensitive drums 52a to 52d to the intermediate transfer member 50. The applied voltage can be reversed between the case where the image is transferred from the intermediate transfer member 50 onto the recording medium 53.

  Conventionally, as the conductive endless belt used as the endless belt-like transfer / conveying belt 10 or the intermediate transfer members 20, 50, a belt composed of a polyester thermoplastic elastomer and a thermoplastic resin is mainly used. It is used. For example, Patent Document 1 includes 51 to 96 mass% of polyalkylene terephthalate (PAT) having a melt index (MI) of 1.0 to 30 g / 10 min, a melting point of 100 ° C. or higher and lower than the melting point of the PAT, and A seamless belt comprising a resin component comprising 49 to 4% by mass of a thermoplastic elastomer having a difference in compatibility parameter with the PAT of less than 2.0 is disclosed. Patent Document 2 discloses that in an endless belt formed by blending a thermoplastic elastomer, a thermoplastic resin, and a conductive substance, the thermoplastic elastomer is a polyester-based thermoplastic elastomer, and the thermoplastic elastomer and the thermoplastic resin are used. An image forming apparatus belt containing 0.1 to 30 parts by mass of a conductive substance with respect to 100 parts by mass of the thermoplastic polymer component is disclosed.

  However, when a polyester resin is used, a decrease in molecular weight due to hydrolysis occurs, resulting in a decrease in rigidity, resulting in difficulty in durability, and in particular, the tendency is more pronounced under high temperature and high humidity. was there. Therefore, for example, Patent Document 3 has physical properties that can withstand repeated continuous use in terms of mechanism, in particular bending durability and set resistance, as well as having an appropriate elastic modulus and causing problems such as image displacement. In order to provide a conductive endless belt free from the above, it mainly contains at least one thermoplastic polyester elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and is tensile. A conductive endless belt having an elastic modulus of 800 MPa or more is disclosed. Specifically, in Comparative Example 3 of Patent Document 3 described above, when the polyester elastomer is included and the carbodiimide and the thermoplastic polyester resin are not included, the melt stability is poor and the dimensional stability accuracy is deteriorated. Therefore, it is disclosed that it is difficult to form a belt, and therefore, it is disclosed that a carbodiimide compound is added to a polyester resin to prevent hydrolysis and improve durability.

Patent Document 4 discloses a carbodiimide for a resin base material comprising (a) a thermoplastic polyalkylene naphthalate resin and / or (b) a thermoplastic polyalkylene terephthalate resin and (c) a thermoplastic polyester elastomer. A conductive endless belt comprising a compound is disclosed. Furthermore, Patent Document 5 discloses a conductive endless belt in which a base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, an outermost layer is mainly composed of a thermoplastic resin, and contains a carbodiimide compound. Furthermore, Patent Document 6 discloses that polyamideimide can be added to an endless belt-shaped transfer member containing a polyarylate resin.
Japanese Patent No. 3701701 (claims, etc.) Japanese Patent No. 3891160 (Claims etc.) JP 2007-47772 A (Claims etc.) JP 2007-25130 A (Claims etc.) JP 2007-156424 A (Claims etc.) JP 2000-137389 A (Claims etc.)

  Patent Documents 3 to 6 disclose that it is preferable to mix a carbodiimide compound in consideration of hydrolysis with respect to a conductive belt composed of a blend of a polyester-based thermoplastic elastomer and a thermoplastic resin. Yes. However, since the carbodiimide compound is in the form of a powder having a low melting point, and the addition amount of the carbodiimide compound is very small, it is necessary to add equipment such as adding a feeder during kneading. Therefore, the handling property improvement is carried out using a product (trade name: Carbodilite E pellets manufactured by Nisshinbo Industries, Ltd.) masterbatched to polyethylene terephthalate (PET) resin, etc. Since the melting point of the base polymer is low because of its high melting point, there has been a problem in that fracturing defects occur and mass productivity deteriorates. Moreover, although a master batch with polybutylene terephthalate (PBT) is desired, since it is handled as a custom-made product, there is a problem that it is expensive and expensive. As a result, a conductive endless belt to which no carbodiimide compound is added has been desired.

  However, when the carbodiimide compound is not added as described above, there is a problem that the molecular weight of the polyester resin is lowered by hydrolysis, the folding resistance is deteriorated, and cracking occurs. In addition, by using a thermoplastic elastomer alone without adding a carbodiimide compound, it is possible to eliminate the deterioration of the folding resistance, but the problem is that the dissolution stability is deteriorated, and image displacement due to undulation and undulation occurs. was there. In addition, it was difficult to ensure rigidity.

  Therefore, the object of the present invention is to solve the above-mentioned problems in the prior art and to achieve both flexibility and rigidity without adding a carbodiimide compound, and has a problem of image misalignment due to undulation and undulation. It is an object of the present invention to provide a conductive endless belt that does not cause the problem and an image forming apparatus using the same.

  As a result of intensive studies, the inventor has made a conductive endless belt excellent in flexibility and rigidity by adding a specific amount of a polyester-based thermoplastic resin to a polyester-based thermoplastic elastomer in a single-layered belt. As a result, the present invention has been completed.

  That is, the conductive endless belt of the present invention is a conductive endless belt containing a polyester-based thermoplastic elastomer and a polyester-based thermoplastic resin used in an image forming apparatus, wherein the polyester-based thermoplastic elastomer is replaced with the polyester-based thermoplastic resin. It is characterized by comprising a single layer structure containing many.

  The conductive endless belt of the present invention preferably has a mass ratio of 80:20 to 60:40 of the polyester thermoplastic elastomer and the polyester thermoplastic resin.

  Furthermore, in the conductive endless belt of the present invention, the polyester-based thermoplastic elastomer is preferably a polyalkylene terephthalate elastomer, and the polyalkylene terephthalate elastomer is preferably a polybutylene terephthalate elastomer.

  Furthermore, in the conductive endless belt of the present invention, the polybutylene terephthalate elastomer preferably has a tensile modulus of 400 MPa or more, and the polybutylene terephthalate elastomer has an MFR value at a temperature of 230 ° C. of 15 g / 10 min or less. Preferably there is.

  The image forming apparatus of the present invention is characterized by using the conductive endless belt.

  According to the present invention, with the above-described configuration, without adding a carbodiimide compound, both flexibility and rigidity can be achieved, and the film has good folding resistance and does not cause image misalignment due to swells and undulations. An endless belt and an image forming apparatus using the same can be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail.
Generally, there are conductive endless belts with joints and belts without joints (so-called seamless belts), but any of them may be used in the present invention, and a seamless belt is preferable. As described above, the conductive endless belt of the present invention can be used as a transfer member for a tandem system or an intermediate transfer system.

  When the conductive endless belt of the present invention is, for example, a transfer conveyance belt indicated by reference numeral 10 in FIG. 2, the toner is sequentially transferred onto a recording medium that is driven by a driving member such as a driving roller 9 and the like. As a result, a color image is formed.

  Further, when the conductive endless belt of the present invention is an intermediate transfer member indicated by reference numeral 20 in FIG. 3, for example, this is circulated by a driving member such as a driving roller 30 and a photosensitive drum (latent image holding member). 11 and the recording medium 26 such as paper, the toner image formed on the surface of the photosensitive drum 11 is temporarily transferred and held, and then transferred to the recording medium 26. Note that the apparatus of FIG. 3 performs color printing by the intermediate transfer method as described above.

  Furthermore, when the conductive endless belt of the present invention is, for example, an intermediate transfer member denoted by reference numeral 50 in FIG. 4, the space between the developing units 54a to 54d including the photoconductive drums 52a to 52d and the recording medium 53 such as paper. The four-color toner images formed on the surfaces of the photosensitive drums 52 a to 52 d are temporarily transferred and held, and then transferred to the recording medium 53. By transferring, a color image is formed. In the above description, the case of four colors of toner has been described. Needless to say, in any apparatus, the number of colors of toner is not limited to four.

  The conductive endless belt of the present invention is a conductive endless belt containing a polyester-based thermoplastic elastomer and a polyester-based thermoplastic resin used in an image forming apparatus, and a single layer containing more polyester-based thermoplastic elastomer than the polyester-based thermoplastic resin. It consists of a structure. As a result, a carbodiimide compound with poor handling properties can be obtained by imparting flexibility with a polyester-based thermoplastic elastomer and imparting rigidity with a polyester-based thermoplastic resin, while enriching the polyester-based thermoplastic elastomer while achieving both. It is possible to realize a single-layer conductive endless belt that suppresses the deterioration of folding resistance, which is a defect that does not require the addition of a carbodiimide compound.

  The conductive endless belt of the present invention contains more polyester-based thermoplastic elastomer than the polyester-based thermoplastic resin, and the mass ratio is not particularly limited as long as a desired effect can be obtained. The mass ratio of the thermoplastic elastomer to the polyester-based thermoplastic resin is 80:20 to 60:40.

  The polyester-based thermoplastic elastomer that can be used for the conductive endless belt of the present invention is not particularly limited as long as the desired effect of the present invention is obtained. For example, polyester-polyester using polyester for the hard segment and the soft segment Both of the type and the polyester-polyether type using polyester for the hard segment and polyether for the soft segment can be suitably used. The hard segment of the polyester-based thermoplastic elastomer is generally a thermoplastic polyalkylene naphthalate resin (for example, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, etc.) or thermoplastic polyalkylene terephthalate. Examples of the resin include polyethylene terephthalate (PET) resin, glycol-modified polyethylene terephthalate (PETG) resin, and polybutylene terephthalate (PBT) resin. In the present invention, polyalkylene terephthalate is preferable. Such polyester-based thermoplastic elastomers can be used in combination of two or more. Moreover, it is preferable that melting | fusing point of a polyester-type thermoplastic elastomer is 210 degreeC or more, and it is more preferable that it is 210-250 degreeC. If the melting point of the polyester elastomer is less than 210 ° C., the tensile elastic modulus (MPa) may be lowered.

  Furthermore, in the present invention, it is preferable to mainly use a polybutylene terephthalate elastomer as the polyester-based thermoplastic elastomer in order to improve flexibility, thereby improving the durability. Although it does not reach the belt added with a carbodiimide compound, the belt characteristics are at least 6000 times of folding resistance, and the belt durability can be satisfied.

  Moreover, it is preferable that the tensile elasticity modulus of the said polybutylene terephthalate elastomer is 400 Mpa or more, and it is further more preferable that it is 500 Mpa. When the tensile elastic modulus of the polybutylene terephthalate elastomer is 400 MPa or more, it is easy to ensure rigidity, which is preferable. Examples of the polybutylene terephthalate elastomer satisfying such conditions include Perprene E450B manufactured by Toyobo Co., Ltd.

  Furthermore, the MFR value at a temperature of 230 ° C. of the polybutylene terephthalate elastomer is preferably 15 g / 10 min or less, more preferably 13 g / 10 min or less. Thereby, set resistance becomes more favorable. If the MFR value is higher than this range, the rigidity may decrease, which is not preferable. Here, the MFR value at a temperature of 230 ° C. is based on the fact that the temperature during melt-kneading and belt molding is around 230 ° C. in consideration of the melting point of the thermoplastic polybutylene terephthalate elastomer.

  Specific examples of the polyester-based thermoplastic resin that can be used in the conductive endless belt of the present invention include thermoplastic polyalkylene naphthalate resins (for example, PEN resin and PBN resin), and thermoplastic polyalkylene terephthalates. Resins (for example, PET resin, PETG resin, PBT resin, etc.) can be mentioned, but are not particularly limited. Such polyester resins may be used in combination of two or more.

  Such a polyester-based thermoplastic resin is preferably a polyalkylene terephthalate, and more preferably the polyalkylene terephthalate is PBT. By using polyalkylene terephthalate, moldability due to an increase in melt viscosity can be further improved, and rigidity can be improved to prevent image shift.

  The conductive endless belt of the present invention preferably does not contain a carbodiimide compound. Thereby, the problem of the deterioration of the handling property at the time of shaping | molding by carbodiimide compound addition, and the mass productivity deterioration by the goods etc. which made PET resin the masterbatch can be solved.

  Further, a conductive agent can be blended in the layer constituting the belt of the present invention in order to adjust the conductivity. Such a conductive agent is not particularly limited, and a known electronic conductive agent, ionic conductive agent, or the like can be appropriately used. Of these, specific examples of the electronic conductive agent include conductive carbon such as ketjen black and acetylene black, carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, oxidation treatment, and the like. Colored (ink) carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium and other metal and metal oxides, polyaniline, Conductive polymers such as polypyrrole and polyacetylene, carbon whisker, graphite whisker, titanium carbide whisker, conductive potassium titanate whisker, conductive barium titanate whisker, conductive titanium oxide whisker, conductive zinc oxide whisker, etc. Is mentioned. Specific examples of the ion conductive agent include perchlorates such as tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium, chlorate, Ammonium salts such as hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate, carboxylate, sulfonate, alkali metals such as lithium, sodium, potassium, calcium, magnesium And alkaline earth metal perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, trifluoromethyl sulfates, sulfonates, and the like.

  Examples of the polymeric ion conductive agent are described in JP-A-9-227717, JP-A-10-120924, JP-A-2000-327922, JP-A-2005-60658, and the like. Although what can be used can be used, it is not specifically limited.

Specific examples include a mixture of (A) an organic polymer material, (B) an ionically conductive polymer or copolymer, and (C) an inorganic or low molecular weight organic salt, wherein the component ( A) is a polyacrylic ester, polymethacrylic ester, polyacrylonitrile, polyvinyl alcohol, polyvinyl acetate, polyamide such as polyamide 6, polyurethane or polyester, and component (B) is an oligoethoxylated acrylate or methacrylate, aromatic Styrene, polyether urethane, polyether urea, polyether amide, polyether ester amide or polyester-ether block copolymer oligoethoxylated for the ring, and component (C) is an inorganic or low molecular weight organic polymer. An alkali metal, alkaline earth metal, zinc or ammonium salt of tons acid, _{preferably, LiClO 4, LiCF 3 SO 3} , NaClO 4, LiBF 4, NaBF 4, KBF 4, NaCF 3 SO 3, KClO 4, KPF ₆ , KCF ₃ SO ₃ , KC ₄ F ₉ SO ₃ , Ca (ClO ₄ ) ₂ , Ca (PF ₆ ) ₂ , Mg (ClO ₄ ) ₂ , Mg (CF ₃ SO ₃ ) ₂ , Zn (ClO ₄ ) ₂ Zn (PF ₆ ) ₂ or Ca (CF ₃ SO ₃ ) ₂ .

Among these, as the component (B), a polymer ionic conductive agent containing a polyether amide component, a polyether ester amide component or a polyester-ether block copolymer component is suitable, and in addition to this, the component (C) It is preferable to contain a low molecular ion conductive agent component. Further, as the polyether amide component and the polyether ester amide component, those in which the polyether component contains (CH ₂ —CH ₂ —O) and the polyamide component contains polyamide 12 or polyamide 6 are particularly preferable. As the low molecular ion conductive agent component of component (C), a polymer ion conductive agent containing NaClO ₄ is particularly suitable. Such polymeric ion conductive agents are readily available on the market as, for example, Irgastat (registered trademark) P18 and Irgastat (registered trademark) P22 (both manufactured by Ciba Specialty Chemicals, Inc.).

  A block copolymer in which a polyolefin block and a hydrophilic polymer block are repeatedly and alternately bonded through an ester bond, an amide bond, an ether bond, a urethane bond, an imide bond, etc. It can be suitably used as a molecular ion conductive agent. Examples of such polyolefins include polyolefins having functional groups such as a carboxyl group, a hydroxyl group, and an amino group at both ends of the polymer, and polypropylene and polyethylene are particularly preferable.

  Further, as the hydrophilic polymer, a polyether diol such as polyoxyalkylene having a hydroxyl group as a functional group, a polyether ester amide composed of a polyamide having both terminal carboxyl groups and a polyether diol, a polyamide imide and a polyether diol Polyetheramide imide composed of polyester, polyether ester composed of polyester and polyether diol, polyether amide composed of polyamide and polyether diamine, etc. can be used. preferable. For example, polyoxyethylene (polyethylene glycol) and polyoxypropylene (polypropylene glycol) having hydroxyl groups at both terminals are used.

Such a block copolymer that can be used as a polymer ion conductive agent in the present invention is readily available on the market as Pelestat 230, 300, 303 (manufactured by Sanyo Chemical Co., Ltd.). In addition, by incorporating the lithium compound LiCF ₃ SO ₃ into the block copolymer, the effect of maintaining the antistatic effect can be obtained even if the addition amount is reduced, and the mixture of the block copolymer and the lithium compound is obtained. Sanconol TBX-310 (manufactured by Sanko Chemical Co., Ltd.) is commercially available.

  When a polymer ion conductive agent is used as the conductive agent, a compatibilizing agent may be added in order to enhance the compatibility between the base resin and the polymer ion conductive agent. Examples of the compatibilizer include the same ones as described above.

  These conductive agents may be used singly or in appropriate combination of two or more. For example, an electronic conductive agent and an ionic conductive agent may be used in combination. Conductivity can be expressed stably even with respect to voltage fluctuations and environmental changes.

  The blending amount of the conductive agent is usually 100 parts by mass or less, for example, 1 to 100 parts by mass, particularly 1 to 80 parts by mass, especially 5 to 50 parts by mass with respect to 100 parts by mass of the resin component. is there. Moreover, about an ion conductive agent, it is 0.01-10 mass parts normally with respect to 100 mass parts of resin components, Especially it is the range of 0.05-5 mass parts. Furthermore, about a polymeric ion electrically conductive agent, it is about 1-500 mass parts normally with respect to 100 mass parts of resin components, Preferably it is about 10-400 mass parts. In the present invention, it is particularly preferable to add 5 to 30 parts by mass of carbon black as a conductive agent with respect to 100 parts by mass of the resin component.

  Further, in the belt of the present invention, other functional components can be appropriately added in addition to the above-mentioned components within a range not impairing the effects of the present invention. For example, various fillers, coupling agents, Antioxidants, lubricants, surface treatment agents, pigments, ultraviolet absorbers, antistatic agents, dispersants, neutralizing agents, foaming agents, crosslinking agents, and the like can be appropriately blended. Furthermore, you may color by adding a coloring agent.

  The tensile elastic modulus of the conductive endless belt of the present invention is preferably 800 MPa or more, more preferably 1000 MPa or more. It is preferable that the tensile modulus of the conductive endless belt is 800 MPa or more because rigidity can be easily secured.

  The total thickness of the conductive endless belt of the present invention is appropriately selected according to the form of the transfer / conveying belt or the intermediate transfer member, but is preferably in the range of 50 to 200 μm. Further, the surface roughness is preferably 10 μm or less, particularly 6 μm or less, more preferably 3 μm or less in terms of JIS 10-point average roughness Rz.

  The conductive endless belt of the present invention has a single layer structure. Thereby, there can be provided a belt having sufficient flexibility (bending resistance) at a low cost without causing a problem of delamination in the laminated structure.

  Further, the conductive endless belt of the present invention has a surface on the side in contact with a driving member such as the driving roller 9 or the driving roller 30 of FIG. 3 in the image forming apparatus shown in FIG. A fitting portion that fits with a fitting portion (not shown) formed on the drive member may be formed, and the conductive endless belt of the present invention is provided with such a fitting portion and drives this. Shifting in the width direction of the conductive endless belt can be prevented by running with a fitting portion (not shown) provided on the member.

  In this case, the fitting portion is not particularly limited, but, as shown in FIG. 1, it is formed as a ridge continuous along the circumferential direction (rotation direction) of the belt, and this is a driving member such as a driving roller. It is preferable to be fitted in a groove formed in the circumferential surface along the circumferential direction.

  In addition, although the example which provided one continuous protruding item | line as a fitting part was shown in Fig.1 (a), this fitting part has many convex parts along the circumferential direction (rotation direction) of a belt. They may be arranged in a row, or two or more fitting portions may be provided (FIG. 1 (b)), or may be provided at the center in the width direction of the belt. Further, a groove along the circumferential direction (rotating direction) of the belt is provided as a fitting portion instead of the convex strip shown in FIG. 1, and this is formed along the circumferential direction on the circumferential surface of the driving member such as the driving roller. You may make it make it fit with the protruding item | line which did.

  Furthermore, the manufacturing method of an electroconductive endless belt should just include the process of extruding the resin composition containing the said polyester-type thermoplastic elastomer and polyester-type thermoplastic resin, and is produced by extrusion molding of this invention. The belt is particularly excellent in the required performance. Specifically, for example, a polyester-based thermoplastic elastomer and a resin composition comprising a polyester-based thermoplastic resin and a functional component such as a conductive material are kneaded by a biaxial kneader, and the obtained kneaded product is mixed with an annular die. Can be produced by extrusion molding. Alternatively, a powder coating method such as electrostatic coating, a dip method, or a centrifugal casting method can also be suitably employed.

Hereinafter, the present invention will be described in more detail with reference to examples.
Conductive endless belts of Examples 1 and 2 and Comparative Example 1 were prepared with the formulations shown in Table 1 below. Specifically, each compounding component is melt-kneaded by a twin-screw kneader, and the obtained kneaded product is extruded using an annular die, whereby a conductive material having dimensions of an inner diameter of 220 mm, a thickness of 80 μm, and a width of 250 mm. A sex endless belt was obtained. In addition, the compounding quantity in Table 1 shows a mass part.

  The obtained belts of Examples 1 and 2 and Comparative Example 1 were evaluated according to the following procedure. These results are also shown in Table 1 below.

<Measurement of tensile modulus>
The tensile modulus was measured under the following conditions.
Apparatus: Manufactured by Shimadzu Corporation, tensile tester EZ test (analysis software: Trappezium)
Sample: strip shape (length 100 mm x width 10 mm x standard thickness 100 μm)
Tensile speed: 5mm / sec
Data sampling interval: 100 msec
Measuring method: inclination at 0.5 to 0.6% elongation (when described, tangent method described in JIS)
Measurement environment: Room temperature (23 ± 3 ° C, 55 ± 10% RH)

<Volume resistance measurement>
The volume resistivity of the belt at a measurement voltage of 500 V was measured at a temperature of 20 ° C. and a relative humidity of 50% by using a resistance meter R8340A connected to a sample chamber R12704A as a measuring device. .

<Folding resistance>
A test piece having a length of 100 mm and a width of 15 mm was cut out from each belt, and a bending speed of 175 times / min, a rotation angle of 135 degrees, and a tensile load of 14.7 N (using Toyo Seiki Co., Ltd. MIT fatigue resistance tester) The number of bending resistances was measured under the condition of 1.5 kgf). The higher the number, the better the result.

<Set resistance>
Each belt was left to stand for 24 hours in a state where the temperature was 30 ° C. and the relative humidity was 85%, and the evaluation was performed based on the running property when the belt was mounted on an actual machine and run. When there was no change in running performance, “◯” was given, when “slightly” meandering or idling occurred, “△”, and when severe meandering or idling occurred, “x”.

<Image shift>
The belts of the examples and comparative examples were mounted on a tandem image forming apparatus using the transfer conveyance belt shown in FIG. 2 and evaluated for the occurrence of image misalignment during the transfer operation. When there was no image shift, “◯” was given, when a slight shift was made, “△”, and when a big shift was made, “X” was given.

＊１）Ｅ−４５０Ｂ（ポリブチレンテレフタレートエラストマー（結晶融点２２２℃、引張弾性率１０００ＭＰａ）、東洋紡（株）製）
＊２）８００ＦＰ（ポリブチレンテレフタレート、ポリプラスチックス(株)製）
＊３）デンカブラック粒状（カーボンブラック、電気化学工業（株）製）
※）溶融安定性が悪く、寸法精度が悪化し画像ずれ発生

* 1) E-450B (polybutylene terephthalate elastomer (crystalline melting point 222 ° C., tensile elastic modulus 1000 MPa), manufactured by Toyobo Co., Ltd.)
* 2) 800FP (polybutylene terephthalate, manufactured by Polyplastics Co., Ltd.)
* 3) Denka black granular (carbon black, manufactured by Denki Kagaku Kogyo Co., Ltd.)
*) Poor melting stability, dimensional accuracy deteriorates and image shift occurs

  The MFR value was measured under the conditions of a temperature of 230 ° C., a preheating of 10 minutes, and a load of 5 kg in accordance with ASTM D1238. The MFR value of E-450B was 10 g / 10 min.

  As shown in Table 1 above, it was confirmed that the belts of the examples had good set resistance and prevented image displacement while maintaining the folding characteristics of at least 6000 times as the belt characteristics. On the other hand, Comparative Example 1 has good folding resistance and set resistance, but has poor melt stability and image displacement.

It is width direction sectional drawing of the electroconductive endless belt which concerns on one embodiment of this invention. FIG. 2 is a schematic diagram illustrating a tandem image forming apparatus using a transfer conveyance belt as an example of an image forming apparatus. FIG. 6 is a schematic diagram illustrating an intermediate transfer device using an intermediate transfer member as another example of an image forming apparatus. FIG. 10 is a schematic diagram illustrating another intermediate transfer apparatus using an intermediate transfer member as still another example of the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11, 52a-52d Photosensitive drum 2, 7 Charging roll 3 Developing roll 4 Developing blade 5 Toner supply roll 6 Cleaning blade 8 Static elimination roll 9, 30, 55 Driving roller (driving member)
DESCRIPTION OF SYMBOLS 10 Transfer conveyance belt 12 Primary charger 13 Image exposure 14, 35 Cleaning device 19 Paper feed cassette 20, 50 Intermediate transfer member 25 Transfer roller 26, 53 Recording medium 29, 61 Power supply 41, 42, 43, 44 Developer 54a-54d First developing section to fourth developing section 56 Recording medium feeding roller 57 Recording medium feeding apparatus 58 Fixing apparatus 59 Power supply apparatus (voltage applying means)

Claims (7)

In a conductive endless belt containing a polyester-based thermoplastic elastomer and a polyester-based thermoplastic resin used in an image forming apparatus,
A conductive endless belt comprising a single-layer structure containing more of the polyester-based thermoplastic elastomer than the polyester-based thermoplastic resin.   2. The conductive endless belt according to claim 1, wherein a mass ratio of the polyester thermoplastic elastomer to the polyester thermoplastic resin is 80:20 to 60:40.   The conductive endless belt according to claim 1 or 2, wherein the polyester-based thermoplastic elastomer is a polyalkylene terephthalate elastomer.   The conductive endless belt according to claim 3, wherein the polyalkylene terephthalate elastomer is a polybutylene terephthalate elastomer.   The conductive endless belt according to claim 4, wherein the polybutylene terephthalate elastomer has a tensile elastic modulus of 400 MPa or more.   The conductive endless belt according to claim 4 or 5, wherein the MFR value of the polybutylene terephthalate elastomer at a temperature of 230 ° C is 15 g / 10 min or less.   An image forming apparatus using the conductive endless belt according to claim 1.

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