JP2007156424A - Conductive endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive endless belt, which has superior durability in addition to various required performance of belts, such as elastic modulus or charging characteristic, and also which can satisfy the required performance, even regarding point of glossiness or set resistance properties without causing problems of image shift or the like; and to provide an image forming apparatus that uses the same. <P>SOLUTION: The endless belt has a tandem system for transfer and conveyance; wherein a recording medium held by electrostatic chuck is circulated and driven by a driving member, which is conveyed to four kinds of imaging elements, and each toner image is sequentially transferred to the recording medium. The endless belt has a multilayer structure, comprising at least a base layer and an outermost layer starting from the inside, which is formed by coextrusion. The base layer has a thermoplastic elastomer as the main component with crystal melting point of 210°C or higher, and the outermost layer contains a thermoplastic resin as the main component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention supplies a developer to 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 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 in this way onto 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 disadvantage 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 a tandem intermediate transfer method that combines a tandem method and an intermediate transfer method. FIG. 4 illustrates an image forming apparatus of a tandem intermediate transfer system that forms a color image using an endless belt-like tandem intermediate transfer member.

  In the illustrated apparatus, the first developing unit 54 a to the fourth developing unit 54 d that develop the electrostatic latent images on the photoconductive drums 52 a to 52 d with yellow, magenta, cyan, and black, respectively, along the tandem intermediate transfer member 50. The four-color toner images formed on the photosensitive drums 52a to 52d of the developing units 54a to 54d are sequentially driven by circulating the tandem intermediate transfer member 50 in the direction of the arrow in the drawing. By transferring, a color toner image is formed on the tandem 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 tandem intermediate transfer member 50, reference numeral 56 denotes a recording medium feeding roller, reference numeral 57 denotes a recording medium feeding device, and reference numeral 58 denotes a recording medium. 3 shows a fixing device for fixing the image by heating or the like. Reference numeral 59 denotes a power supply device (voltage applying means) for applying a voltage to the tandem intermediate transfer member 50. The power supply device 59 transfers the toner image from the photosensitive drums 52a to 52d to the tandem intermediate transfer member 50. In this case, the polarity of the applied voltage can be reversed between the case where the image is transferred from the tandem intermediate transfer member 50 onto the recording medium 53.

Conventionally, as the conductive endless belt used as the endless belt-like transfer conveyance belt 10, the intermediate transfer member 20, the tandem intermediate transfer member 50, etc., a semiconductive resin film belt, a rubber belt having a fiber reinforcement, Is mainly used. Among these, as the resin film belt, for example, Patent Document 1 discloses a conductive endless belt using a thermoplastic polyalkylene naphthalate resin or a polymer alloy or a polymer blend of the thermoplastic polyalkylene naphthalate resin and another thermoplastic resin as a base material. ing. Patent Document 2 discloses a conductive base layer in which a conductive filler is dispersed in a polyester polyether resin having a melting point of 160 to 210 ° C., and has a predetermined loss tangent (tan δ) and volume resistivity. An electrically conductive seamless belt is disclosed.
JP 2002-132053 A (Claims etc.) Japanese Patent Laid-Open No. 2000-62993 (claims, etc.)

  By the way, when controlling the rotational position of the belt at the time of driving by an optical sensor, the glossiness of the belt surface is important. In this regard, when belt production is performed by a molding method using a mold, the surface property of the belt can be controlled by the mold, so problems do not easily occur. However, when belt production is performed only by extrusion molding (reference) Document: Japanese Patent Laid-Open No. 2001-138380), the influence of the belt material on the surface property becomes large. On the other hand, the belt described in Patent Document 1 has high glossiness, but on the other hand, there is a problem in belt durability due to insufficient flexibility, and in a high temperature and high humidity environment. There is also a problem that the setability deteriorates due to the progress of crystallization of the resin with the use of the resin.

  Further, the belt described in Patent Document 2 is excellent in durability because it uses an elastomer having a low melting point, but image misalignment due to the occurrence of elongation, image deterioration due to deformation in a high temperature and high humidity environment, and the like. There was a problem.

  Therefore, in addition to various required performances of the belt such as elastic modulus and charging characteristics, the object of the present invention is to have more excellent durability and satisfy the required performance in terms of glossiness and set resistance. It is an object of the present invention to provide a conductive endless belt that does not cause problems such as image misalignment and an image forming apparatus using the same.

  As a result of intensive studies to solve the above problems, the present inventors have made the belt a laminated structure composed of a plurality of layers, and by ensuring each layer has different required performance, it is more excellent without impairing other belt performance. The present invention has been completed by finding that a belt can be realized that has excellent durability, glossiness and set resistance.

In other words, the conductive endless belt of the present invention is configured to circulate and drive a recording medium held by electrostatic adsorption to four types of image forming bodies by a driving member, and sequentially transfer each toner image to the recording medium. For conductive endless belts for tandem transfer and transport,
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. It is characterized by having a main component.

Further, another conductive endless belt of the present invention is disposed between the image forming body and the recording medium, and is circulated and driven by a driving member to temporarily transfer the toner image formed on the surface of the image forming body. In the conductive endless belt for the intermediate transfer member that is transferred and held on the surface and transferred to the recording medium,
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. It is characterized by having a main component.

Furthermore, another conductive endless belt according to the present invention is disposed between the four types of image forming bodies and the recording medium, and is circulated by a driving member to be formed on the surface of the four types of image forming bodies. In the conductive endless belt for a tandem intermediate transfer member that sequentially transfers and holds the toner images to the surface of the toner, and transfers the toner images to a recording medium.
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. It is characterized by having a main component.

  In the present invention, a polyester resin is preferably used as the thermoplastic resin, and a polyester elastomer is preferably used as the thermoplastic elastomer. In this case, the outermost layer or the base layer preferably contains a carbodiimide compound. Furthermore, the tensile elastic modulus of the belt of the present invention is preferably 800 MPa or more. In the belt of the present invention, the “base layer” means the thickest layer in the laminated structure.

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

  According to the present invention, in addition to the various required performances of the belt such as the elastic modulus and charging characteristics, the above-described configuration provides superior durability, and the required performance in terms of glossiness and set resistance. A satisfactory belt can be realized. Therefore, according to the image forming apparatus using the belt of the present invention, it is possible to provide a good image without causing problems such as image displacement caused by the elongation or deformation of the belt.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In general, the conductive endless belt includes a jointed belt and a jointless belt (so-called seamless belt), but any one may be used in the present invention. 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, an intermediate transfer system, and a tandem 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, a tandem intermediate transfer member denoted by reference numeral 50 in FIG. 4, the developing units 54a to 54d including the photosensitive drums 52a to 52d and the recording medium 53 such as paper are provided. 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. To form a color image.

  FIG. 1 is a cross-sectional view in the width direction of a conductive endless belt according to a preferred embodiment of the present invention. As shown in the figure, the conductive endless belt 100 of the present invention has a laminated structure including at least a base layer 101 and an outermost layer 102 sequentially from the inside, and the base layer 101 is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher. In addition, the outermost layer 102 has a thermoplastic resin as a main component. That is, a desired belt characteristic is realized by making the belt multilayer and using different materials for each layer.

  As described above, the base layer 101 in the belt of the present invention forms the thickest layer of the laminated structure, and thus occupies at least 50%, preferably 60 to 99% of the total belt thickness. In the present invention, such a base layer is formed with a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, preferably 215 to 230 ° C. as a main component, so that the belt has a tensile elastic modulus of 800 MPa or higher, particularly 800 to 2000 MPa. It was possible to achieve this, and it was possible to ensure excellent bending durability. With a thermoplastic elastomer having a crystal melting point of less than 210 ° C., the set resistance under a high temperature and high humidity environment is deteriorated, which may cause problems such as image displacement.

  The thermoplastic elastomer used for the base layer is not particularly limited as long as it has a crystal melting point of 210 ° C. or higher. For example, polyester-based, polyamide-based, polyether-based, polyolefin-based, polyurethane-based, styrene-based, acrylic-based, polydiene-based The polyester type elastomer is preferably used. In particular, it is preferable to use a polyester-based elastomer and use a polyester resin in combination with this to further improve the elastic modulus. The ratio of both in this case can be 10-50 weight part of polyester resins with respect to 90-50 weight part of polyester-type elastomers, for example.

  Such thermoplastic polyester elastomers include both polyester-polyester type using polyester for hard segment and soft segment, and polyester-polyether type using polyester for hard segment and polyether for soft segment. It can be used suitably. The hard segment of the polyester elastomer is generally composed mainly of polybutylene terephthalate (PBT) or polybutylene naphthalate (PBN), but any of them can be used in the present invention. . Moreover, as a polyester-type resin which can be used together, the thing similar to what is used for the outermost layer mentioned later can be used.

  In addition, when using a thermoplastic polyester-type elastomer as a main component of a base layer, since it is a polyester-type resin, there exists a difficulty that it is easy to cause the molecular weight fall by hydrolysis at the time of shaping | molding heating. Therefore, in the present invention, it is preferable to add a compound having a carbodiimide group to the base layer to recrosslink the thermoplastic polyester elastomer by the reaction between the carbodiimide group and the carboxylic acid, thereby preventing a decrease in molecular weight. Thereby, embrittlement of the belt can be prevented, and the crack resistance of the belt at the time of durability can be improved. Such carbodiimide compounds are easily available on the market, and examples thereof include trade name: Carbodilite manufactured by Nisshinbo Industries, Inc. The carbodiimide compound can also be used in the form of a masterbatch pellet or the like, for example, Nisshinbo Co., Ltd. trade name: Carbodilite E pellet, B pellet or the like can be suitably used.

  The amount of the carbodiimide compound added is not particularly limited, but is preferably 0.05 to 30 parts by weight, and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin component of the base layer. Is within the range.

  Further, as the thermoplastic resin used for the outermost layer of the belt of the present invention, it is preferable to use one having a high glossiness on the belt surface when the outermost belt layer is formed by extrusion, and the higher the better. For example, a thermoplastic resin that can obtain a gloss value of 60 or more, particularly 70 or more as measured by a commercially available gloss meter is suitable.

  Specifically, for example, polyalkylene naphthalate resin (for example, polyethylene naphthalate (PEN) resin, PBN resin, etc.) or polyalkylene terephthalate resin (for example, polyethylene terephthalate (PET) resin, glycol-modified PET (PETG) resin, PBT) Resin) and the like, polyamide (PA), acrylonitrile-butadiene-styrene (ABS) resin, polyacetal (POM), polyarylate (PAR), polycarbonate (PC), polyethylene (PE), polypropylene (PP), Polystyrene (PS), polymethyl methacrylate (PMMA), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), acrylonitrile styrene (AS (SAN)), polyether sulfone (PES), polyetheretherketone (PEEK), polymethylpentene (PMP), polyphenylene ether (PPE), ethylenetetrafluoroethylene copolymer (ETFE), or a mixture of two or more of these may be used. Preferably, a polyester resin is used.

  Even when a polyester resin is used as the main component of the outermost layer, the carbodiimide compound is used in the outermost layer for the purpose of preventing a decrease in molecular weight due to hydrolysis during molding heating, as in the case of the polyester elastomer. It is preferable to contain. The amount of the carbodiimide compound added in this case is not particularly limited, but is preferably 0.05 to 30 parts by weight, more preferably 0.1 to 100 parts by weight based on 100 parts by weight of the outermost resin component. Within the range of 5 parts by weight.

  The belt of the present invention has a laminated structure including at least a base layer and an outermost layer, but may include other layers on the base layer-outermost layer or on the inner layer side of the base layer. However, also in this case, it is necessary that the base layer forms the thickest layer in the laminated structure. As such another layer, for example, a layer having the same configuration as that of the outermost layer can be laminated on the inner layer side of the base layer. An adhesive layer may be provided between the base layer and the outermost layer.

  Moreover, in each layer which comprises the belt of this invention, in order to adjust electroconductivity, a conductive material is mix | blended. Such a conductive material 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.

  Further, as the polymer ion conductive agent, polyether ester amide can be suitably used. For example, JP-A-9-227717, JP-A-10-120924, and JP-A-2000-327922. Although what is described in Unexamined-Japanese-Patent No. 2005-60658 etc. can be used, it is not specifically limited.

Specifically, mention may be made of a mixture comprising (A) an organic polymer material, (B) an ionically conductive polymer or copolymer, and (C) an inorganic or low molecular weight organic salt, wherein component (A) ) Is a polyacrylic ester, polymethacrylic ester, polyacrylonitrile, polyvinyl alcohol, polyvinyl acetate, polyamide 6, polyamide 12, etc., polyurethane or polyester, and component (B) is an oligoethoxylated acrylate or methacrylate, Styrene, polyether urethane, polyether urea, polyether amide, polyether ester amide or polyester-ether block copolymer oligoethoxylated for the aromatic ring, and component (C) is inorganic or low An alkali metal, alkaline earth metal, zinc or ammonium salt in an amount organic protonic acids, _{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 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 Sanconol TBX-310 (manufactured by Sanko Chemical Co., Ltd.) is commercially available.

  These conductive materials 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. Therefore, the conductivity can be stably expressed even with respect to fluctuations in voltage and environmental changes.

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

  When a polymer ion conductive agent is used as the conductive material, a compatibilizing agent may be added in order to enhance the compatibility between the resin component and the polymer ion conductive agent. Examples of compatibilizers that can be suitably used in the present invention include EVA / EPDM / polyolefin graft copolymers, polyolefin graft copolymers, and reactive (GMA, MAH-containing) polyolefin graft copolymers, P (St-co- GMA), EGMA, P (Et-co-EA-co-MAH), SEBS and its maleic anhydride modified product, oxazoline group-containing styrene-based or acrylonitrile-styrene-based polymer, maleic anhydride-modified EPDM, maleic anhydride-modified PE , Maleic anhydride modified PP, maleic anhydride modified EVA, styrene / maleic anhydride copolymer, SAN graft EPDM, reactive polystyrene, polycaprolactone-b-polystyrene, reactive styrene / acrylonitrile copolymer -, Imidized polyacrylate, ethylene / glycidyl methacrylate acrylic acid copolymer, chlorinated polyethylene, reactive phenoxy, silane compound, peroxide polymer, polycaprolactone, etc. (abbreviations in the above list are respectively EVA: ethylene vinyl acetate Copolymer, EPDM: ethylene-propylene-diene copolymer, EGMA: ethylene-glycidyl methacrylate copolymer, SEBS: styrene-ethylene-butadiene-styrene copolymer, GMA: glycidyl methacrylate, MAH: maleic anhydride EA: ethyl acrylate) and the like. These compatibilizers are preferably added in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the total amount of the resin component and the polymer ion conductive agent. To improve the compatibility of both. To allow for homogeneous and good dispersion of the base material of the polymer ion conductive agent, it is possible to obtain a high-performance conductive endless belt.

  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 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. 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. Furthermore, the volume resistivity is preferably adjusted within the range of 10 ² Ω · cm to 10 ¹³ Ω · cm.

  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 of FIG. 2, as shown by a one-dot chain line 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 carried out.

  Further, as the image forming apparatus of the present invention using the conductive endless belt of the present invention, the tandem system shown in FIG. 2, the intermediate transfer system shown in FIG. 3, or the tandem intermediate transfer system shown in FIG. Although the thing can be illustrated, it is not limited to these. In the case of the apparatus shown in FIG. 3, a voltage can be appropriately applied from the power source 61 to the drive roller 23 or the drive gear for rotating the intermediate transfer member 20 of the present invention. The application conditions, such as the application of weighting the alternating current, can be selected as appropriate.

  The conductive endless belt of the present invention is manufactured by coextrusion of each layer constituting a laminated structure, and has an advantage in that a desired high surface glossiness can be obtained even by such a manufacturing method.

Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-11 and Comparative Examples 1-4
Conductive endless belts of Examples and Comparative Examples were prepared with the formulations shown in Tables 1 to 3 below. Specifically, the blended components of each layer were melt-kneaded with a biaxial kneader, and the obtained kneaded material was extruded with an extruder of φ40 mm, whereby an inner diameter of 220 mm and a total thickness of 100 μm (the thickness of each layer is in the table) A conductive endless belt having a width of 250 mm. For Examples 1 to 4, 6 to 11 and Comparative Example 1, two types of two-layer annular dies are used. For Example 5, two types of three-layer annular dies (the outermost layer and the inner layer have the same configuration) are used. For No. 4, single-layer annular dies were used. The belts of the obtained examples and comparative examples were evaluated according to the following procedures. These results are also shown in Tables 1 to 3 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)

<Measurement of volume resistivity>
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 the bending speed was 175 times / min, the rotation angle was 135 degrees, and the tensile load was 14.7 N (using Toyo Seiki Co., Ltd.). The number of bending resistances was measured under the condition of 1.5 kgf). The results are shown as an index with Comparative Example 2 as 800. The higher the number, the better the result.

<Glossiness>
It measured using the handy gloss meter IG-320 by the Co., Ltd. Co., Ltd. make.

<Set resistance>
Each belt was left to stand for 24 hours in a state where the temperature was 60 ° 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 the tandem type image forming apparatus shown in FIG. 2 and evaluated for the occurrence of image misalignment during the transfer operation. When there was no image shift, “◯” was indicated, and when a large shift was generated, “X” was assigned.

＊１）ＰＢＴ：ポリプラスチックス（株）製、ジュラネックス８００ＦＰ
＊２）ＰＥＴ：ユニチカ（株）製、商品名 ＳＡ１２０６
＊３）ＰＥＴ−Ｇ：イーストマンケミカル社製、商品名 イースター６７６３
＊４）ＰＢＮ：帝人化成（株）製、商品名 ＴＱＢ−ＯＴ
＊５）カルボジイミド化合物：日清紡績（株）製、カルボジライトＥペレット
＊６）カーボンブラック：電気化学工業（株）製、商品名 デンカブラック粒状
＊７）ポリエステルエラストマーＡ：東洋紡（株）製、ペルプレンＥ−４５０Ｂ（結晶融点２２２℃）
＊８）ポリエステルエラストマーＢ：東洋紡（株）製、ペルプレンＰ−９０Ｂ（結晶融点２０３℃）

* 1) PBT: Polyplastics Co., Ltd., Juranex 800FP
* 2) PET: Product name SA1206 manufactured by Unitika Ltd.
* 3) PET-G: Eastman Chemical Co., Ltd., trade name: Easter 6763
* 4) PBN: manufactured by Teijin Chemicals Ltd., trade name: TQB-OT
* 5) Carbodiimide compound: manufactured by Nisshinbo Co., Ltd., Carbodilite E pellet * 6) Carbon black: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name DENKA BLACK granular * 7) Polyester elastomer A: manufactured by Toyobo Co., Ltd., Perprene E -450B (crystalline melting point 222 ° C)
* 8) Polyester elastomer B: manufactured by Toyobo Co., Ltd., Perprene P-90B (crystal melting point 203 ° C.)

＊９）ポリエステルエラストマーＣ：東洋紡（株）製、ペルプレンＥＮ−１６０００（結晶融点２４１℃）
＊１０）ポリエーテルエステルアミド：三洋化成工業（株）製、ペレスタットＮＣ６３２１

* 9) Polyester elastomer C: manufactured by Toyobo Co., Ltd., Perprene EN-16000 (crystal melting point 241 ° C.)
* 10) Polyetheresteramide: manufactured by Sanyo Chemical Industries, Pelestat NC6321

  As shown in Tables 1 to 3 above, the belts of the examples using a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher as the base material for the base layer of the laminated structure and using the thermoplastic resin as the base material for the outermost layer are tensile elastic. While ensuring the belt performance such as the rate, it is possible to realize a belt that has more excellent durability and satisfies the required performance in terms of glossiness and set resistance. Therefore, according to the image forming apparatus using the belt of the present invention, it is possible to provide a good image without causing problems such as image displacement caused by the elongation or deformation of the belt.

It is width direction sectional drawing of the electroconductive endless belt which concerns on one embodiment of this invention. 1 is a schematic diagram illustrating a tandem type image forming apparatus using a transfer conveyance belt as an example of an image forming apparatus of the present invention. FIG. 6 is a schematic view showing an intermediate transfer device using an intermediate transfer member as another example of the image forming apparatus of the present invention. FIG. 6 is a schematic view showing a tandem intermediate transfer device using a tandem intermediate transfer member as another example of the image forming apparatus of the present invention.

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 Intermediate transfer member 25 Transfer roller 26, 53 Recording medium 29, 61 Power supply 41, 42, 43, 44 Developer 50 Tandem intermediate transfer member 54a to 54d First developing portion to fourth developing portion 56 Recording medium feeding roller 57 Recording medium feeding device 58 Fixing device 59 Power supply device (voltage applying means)
100 conductive endless belt 101 base layer 102 outermost layer

Claims (9)

Conductive endless belt for tandem transfer and conveyance, in which a recording medium held by electrostatic adsorption is circulated and driven by a driving member, conveyed to four types of image forming bodies, and each toner image is sequentially transferred to the recording medium. In
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. Conductive endless belt characterized by having a main component. The toner image formed between the image forming body and the recording medium is circulated and driven by a driving member, and the toner image formed on the surface of the image forming body is once transferred and held on the surface of the image forming body and transferred to the recording medium. In the conductive endless belt for the intermediate transfer member
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. Conductive endless belt characterized by having a main component. Arranged between the four types of image forming bodies and the recording medium, and circulated and driven by a driving member, and sequentially transferring and holding the toner images formed on the surfaces of the four types of image forming bodies on the surface of the recording medium. In a conductive endless belt for a tandem intermediate transfer member that transfers this to a recording medium,
It has a laminated structure including at least a base layer and an outermost layer sequentially from the inside, is formed by coextrusion, the base layer is mainly composed of a thermoplastic elastomer having a crystal melting point of 210 ° C. or higher, and the outermost layer is made of a thermoplastic resin. Conductive endless belt characterized by having a main component.   The conductive endless belt according to any one of claims 1 to 3, wherein the thermoplastic resin is a polyester resin.   The conductive endless belt according to any one of claims 1 to 4, wherein the thermoplastic elastomer is a polyester-based elastomer.   The conductive endless belt according to claim 4, wherein the outermost layer contains a carbodiimide compound.   The conductive endless belt according to claim 5, wherein the base layer contains a carbodiimide compound.   The conductive endless belt according to any one of claims 1 to 7, wherein the tensile elastic modulus is 800 MPa or more.   An image forming apparatus using the conductive endless belt according to claim 1.

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