JP2010145631A - Electroconductive endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive endless belt with which a good image is obtained at a lower cost and which has better belt properties. <P>SOLUTION: The electroconductive endless belt 100 has an endless belt shape used in an image forming apparatus and a laminated structure including at least a base layer 101 and a surface layer 102 in order from the inside, wherein the base layer 101 and the surface layer 102 contain a thermoplastic resin and/or a thermoplastic elastomer as a principal component, the base layer 101 is obtained by adding carbon black to the resin component of the base layer 101, and the surface layer 102 is obtained by adding ≤10 pts.mass of an ionic conductive agent based on 100 pts.mass of the resin component of the surface layer 102. The surface layer 102 has a thickness of ≥2 μm and the ratio of the thickness of the surface layer 102 to the total thickness of the electroconductive endless belt 100 is ≤15%. <P>COPYRIGHT: (C)2010,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 the toner image formed in this way onto a recording medium such as paper.

  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 toner is supplied onto the photosensitive member to visualize the electrostatic latent image, 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 the toner images are formed in a row, 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 a conductive endless belt used as the endless belt-like transfer / conveying belt 10 or the intermediate transfer members 20, 50, a semi-conductive resin film belt or a rubber belt having a fiber reinforcement is mainly used. Yes. Among these, as resin film belts, for example, those in which carbon black is mixed with polycarbonate (PC), those using polyalkylene terephthalate as the main resin, those using thermoplastic polyimide as the main resin, and the like are known.

  When carbon black is used as a conductive agent with a thermoplastic resin as the main material, conductivity can be imparted relatively easily. Moreover, it is possible to obtain a belt having excellent surface gloss and smoothness by performing appropriate kneading and molding. However, when the printed image is observed in detail, the toner transfer state is uneven and is not always satisfactory. This is presumed to be caused by the fact that carbon black tends to form an aggregate structure, so that the dispersion state of carbon black on the belt surface is non-uniform from a microscopic viewpoint.

As means for solving this problem, various techniques using an ion conductive conductive agent have been proposed. For example, Patent Documents 1 and 2 disclose a conductive endless belt to which a polymer ion conductive agent is added, and the printing characteristics are improved by using an ion conductive material as the conductive agent. Patent Document 3 discloses a conductive endless belt in which a belt surface is coated with an ultraviolet curable resin mixed with carbon black. Furthermore, Patent Document 4 discloses a conductive endless belt in which a laminated structure including a base layer and a surface layer is formed by coextrusion molding, and a polymer ion conductive agent is used for the surface layer and the base layer.
JP 2003-029537 A (Claims etc.) JP 2003-91177 A (Claims etc.) JP 2006-184785 A (Claims etc.) JP 2007-192996 A (Examples)

  However, the methods described in Patent Documents 1 and 2 improve the voltage dependence and image quality of the resistance value by adding a polymer ion conductive agent to the thermoplastic resin. A large amount of ionic conductive agent needs to be added. Therefore, depending on the amount of the ionic conductive agent, the elastic modulus of the belt may be lowered, and a conductive endless belt having a better elastic modulus is desired. In addition, although the method described in Patent Document 3 is an effective technique for improving the belt surface characteristics, coating is performed after molding the belt as a base material, which increases the manufacturing process and increases the cost. A conductive endless belt that can provide a good image is desired.

  Furthermore, the method described in Patent Document 4 is an effective technique that can obtain a laminated structure without increasing the number of manufacturing steps by using coextrusion molding, and can impart various functions by selecting a surface layer material. However, if the amount of the ionic conductive agent is too large, the surface scratch property may be deteriorated. Even if an appropriate amount of the ionic conductive agent is added, if the surface layer becomes too thick, the proportion of the surface layer in the entire belt increases, and the tensile modulus and the like may be deteriorated. Therefore, there is a demand for a conductive endless belt having better characteristics as a whole belt (surface scratch characteristics, tensile elastic modulus, etc.).

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a conductive endless belt that solves the above-described problems in the prior art, can obtain a good image at a lower cost, and has better belt characteristics.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have made the belt a laminated structure composed of a plurality of layers, each containing a different conductive agent in the surface layer and the base layer, and further adjusting the thickness of the surface layer. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, the conductive endless belt of the present invention is an endless belt used in an image forming apparatus, and has a laminated structure including at least a base layer and a surface layer sequentially from the inside.
The base layer and the surface layer are mainly composed of a thermoplastic resin and / or a thermoplastic elastomer,
The base layer is obtained by adding carbon black to the resin component of the base layer,
The surface layer is formed by adding 10 parts by mass or less of an ionic conductive agent to 100 parts by mass of the resin component of the surface layer,
The thickness of the surface layer is 2 μm or more, and the ratio of the thickness of the surface layer to the total thickness of the conductive endless belt is 15% or less.

  In the conductive endless belt of the present invention, the surface layer preferably contains 3 to 9 parts by mass of an ionic conductive agent with respect to 100 parts by mass of the resin component of the surface layer.

  Further, in the conductive endless belt of the present invention, the resin of the surface layer is preferably composed mainly of polybutylene naphthalate, and the resin of the base layer is made of polybutylene terephthalate and / or polybutylene terephthalate and a polyester elastomer. It is preferable that the blend is a main component.

  Furthermore, the conductive endless belt of the present invention preferably has a tensile elastic modulus of the entire conductive endless belt of 1600 MPa or more.

  According to the present invention, the above configuration makes it possible to realize a conductive endless belt that can obtain a good image at a lower cost and has better belt characteristics.

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.

  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 drawing, the conductive endless belt 100 of the present invention is an endless belt shape used in an image forming apparatus, and has a laminated structure including at least a base layer 101 and a surface layer 102 sequentially from the inside. Reference numeral 102 denotes a main component of a thermoplastic resin and / or a thermoplastic elastomer. Of these, the base layer 101 is obtained by adding carbon black to the resin component of the base layer 101, and the surface layer 102 is added with 10 parts by mass or less of an ionic conductive agent with respect to 100 parts by mass of the resin component of the surface layer 102. It will be. Furthermore, the thickness of the surface layer 102 is 2 μm or more, and the ratio of the thickness of the surface layer 102 to the total thickness of the conductive endless belt is 15% or less.

  That is, in the present invention, a belt is formed in a laminated structure, and a base layer 101 located inside thereof is formed by adding carbon black into the resin, and a surface layer 102 is added with 10 parts by mass or less of an ionic conductive agent in the resin. Furthermore, since the thickness of the surface layer 102 is 2 μm or more and the ratio of the thickness of the surface layer 102 to the total thickness of the conductive endless belt is 15% or less, a good image can be obtained at a lower cost. Thus, a belt having better belt characteristics can be realized. In addition, when carbon black is used for the surface layer 102, color unevenness and color loss may be noticeable, but color unevenness can be sufficiently prevented by using an ionic conductive agent for the surface layer 102. Furthermore, if an ionic conductive agent is used in a single-layer belt, the filling amount increases, and the elastic modulus and wear resistance may decrease. However, since the ionic conductive agent filling amount can be reduced by using a laminated structure, the cost is reduced. Without this, it is possible to prevent the elastic modulus and wear resistance from being lowered and to prevent the belt surface from being damaged.

  As the resin of the surface layer 102 in the belt of the present invention, as a main component of the resin, a known thermoplastic resin or thermoplastic elastomer as a belt material can be appropriately used singly or in combination of two or more, There is no particular limitation.

  Specific examples of the thermoplastic resin include thermoplastic polyalkylene naphthalate resins (for example, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, etc.) and thermoplastic polyalkylene terephthalate resins ( For example, polyester resins such as polyethylene terephthalate (PET) resin, glycol-modified polyethylene terephthalate (PETG) resin, polybutylene terephthalate (PBT) resin), thermoplastic polyamide (PA) (for example, PA11, PA12, PA6, PA66, PA610, PA612, PA46, aromatic nylon (nylon 6T, 9T, MXD6, etc.), acrylonitrile-butadiene-styrene (ABS) resin, thermoplastic polyacetal (POM), thermoplastic polyaryle Preparative (PAR), thermoplastic polycarbonate (PC), and polyethylene (PE) and polypropylene (PP) a polyolefin resin, or the like.

  Examples of the thermoplastic elastomer include various types such as polyester, polyamide, polyether, polyolefin, polyurethane, styrene, acrylic, and polydiene. Among them, thermoplastic polyester Elastomers are preferred. 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. In addition, although the hard segment of the polyester-type elastomer is generally used mainly with PBT or PBN, any thing can be used in this invention.

  In the present invention, the resin of the surface layer 102 is preferably composed mainly of polybutylene naphthalate among the above resins.

  In addition, the base layer 101 in the belt of the present invention can be composed mainly of a thermoplastic resin and / or a thermoplastic elastomer. As such a thermoplastic resin, a general-purpose one can be used, for example, PBT, PBN, PEN, PET, PC, PA, POM, PAR, ABS, polyphenylene sulfide (PPS), polyphenylene ether (PPE), etc. Various thermoplastic elastomers as described above with respect to 102, blends and alloys thereof, and the like can be mentioned, but are not particularly limited. In particular, considering the adhesiveness with the surface layer 102, PBT, PBN, PET, PC, PAR, polyester elastomer and the like are preferable. In the present invention, among the above, a polyester resin and a polyester-based elastomer are preferable, and it is particularly preferable that a main component is polybutylene terephthalate and a blend of polybutylene terephthalate and a polyester-based elastomer. Any one of these may be used alone, or two or more of them may be used in combination as appropriate.

  In addition, since these polyester resins and polyester-based elastomers have the disadvantage that they tend to cause a decrease in molecular weight due to hydrolysis during molding heating, in particular, by adding a compound having a carbodiimide group, the carbodiimide group and the carboxylic acid It is preferable to prevent the molecular weight from decreasing by recrosslinking the polyester resin or the polyester elastomer by reaction. 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.

  In the present invention, the carbon black that can be used for the base layer 101 is not particularly limited as long as the intended effect of the present invention can be obtained. Specifically, for example, a conductive material such as ketjen black or acetylene black is used. Examples thereof include carbon for rubber such as reactive carbon, SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, carbon for color (ink) subjected to oxidation treatment, pyrolytic carbon, and the like. Such carbon black may be used individually by 1 type, or may be used in combination of 2 or more types as appropriate.

  In the present invention, the ionic conductive agent that can be used for the surface layer 102 is not particularly limited as long as the desired effect of the present invention can be obtained. Specifically, for example, tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium. , Hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate , Ammonium salts such as carboxylates and sulfonates, alkali metals such as lithium, sodium, potassium, calcium and magnesium, alkaline earth metal perchlorates, chlorates, hydrochlorides, bromates, iodic acids Salt, borohydrofluoride, sulfate, trifluoromethyl sulfate, Sulfonic acid salts, polymeric ionic conductive agent or the like.

  Examples of such a polymer 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 a thing 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 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 aromatic rings, and component (C) is inorganic or Alkali metal lower molecular weight organic protonic acid, an alkaline earth metal, zinc or ammonium salt, _{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, Ca (CF ₃ SO ₃ ) ₂ or the like.

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 ionic conductive agent is used as the ionic conductive agent, a compatibilizing agent may be added to increase the compatibility between the base resin and the polymer ionic conductive agent.

  Such ionic conductive agents may be used alone or in combination of two or more.

  Moreover, the compounding quantity of the ion conductive agent in the surface layer 102 is 10 mass parts or less normally with respect to 100 mass parts of resin components of the surface layer 102, Preferably, it is the range of 3-9 mass parts. If the amount of the ionic conductive agent in the surface layer 102 exceeds 10 parts by mass, the surface layer 102 becomes soft, wear resistance is poor, and the surface is easily damaged, which is not preferable. Furthermore, the compounding quantity of the carbon black in the base layer 101 is normally 5-50 mass parts with respect to 100 mass parts of resin components of the base layer 101, especially 5-30 mass parts, especially 10-20 mass parts.

  In addition to the above-described components, other functional components can be appropriately added to the belt of the present invention as long as the effects of the present invention are not impaired. For example, various kinds of fillers, reinforcing materials, A flame retardant, a coupling agent, an antioxidant, a lubricant, a surface treatment agent, a pigment, an ultraviolet absorber, an antistatic agent, a dispersant, a neutralizing agent, a foaming agent, a crosslinking agent, and the like can be appropriately blended. Furthermore, you may color by adding a coloring agent.

  The belt of the present invention has a laminated structure including at least the base layer 101 and the surface layer 102, but may include other layers on the base layer-surface layer or the inner layer side of the base layer. As such other layers, for example, a layer having the same configuration as the surface layer can be used by being laminated on the inner layer side of the base layer. An adhesive layer may be provided between the base layer and the surface layer.

  In the present invention, the thickness of the surface layer 102 in the belt is 2 μm or more, and more preferably 4 to 15 μm. The ratio of the surface layer 102 to the total thickness of the conductive endless belt (belt total thickness) is 15% or less, and preferably 5 to 15%. With such a configuration, the elastic modulus can be further prevented from lowering, and the amount of the ionic conductive agent can be reduced, so that the cost can be further reduced.

  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, more preferably 80. Within the range of ~ 100 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.

  In addition, the conductive endless belt of the present invention preferably has a tensile elastic modulus of the entire conductive endless belt of 1600 MPa or more. Thereby, good belt characteristics can be obtained.

    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. You may make it make it fit with the protruding item | line which carried out.

  The conductive endless belt of the present invention can be preferably produced by coextrusion of each layer constituting the laminated structure, and in this case, the adhesiveness at the interface of each layer can be ensured well. Here, the co-extrusion is, for example, in the case of two layers, using two extruders for extruding the material for the base layer and the material for the surface layer, respectively, and one annular die for two layers. This is a method in which materials are simultaneously fed into an annular die, laminated in a die and extruded, and a laminated belt can be obtained in one step and in a short time. In the case of three or more layers, an extruder and a die corresponding to the number of layers may be used. In addition, by devising the flow path in the die, it is possible to stack more layers than the material type. By producing by coextrusion, no solvent is used during production, so the environmental resistance is good and the productivity is further increased. Furthermore, the belt of the present invention can be manufactured by a powder coating method such as electrostatic coating, a dip method, or a centrifugal molding method.

Hereinafter, the present invention will be described in more detail with reference to examples.
Conductive endless belts of Examples and Comparative Examples were prepared with the formulations shown in Tables 1 to 4 below. The compounding amounts in the following table all indicate parts by mass. Specifically, the blended components of each layer are melt-kneaded with a biaxial kneader, and the resulting kneaded product is extruded using a two-type two-layer cylindrical die, whereby an inner diameter of 155 mm and a total thickness (table) 1-4), a conductive endless belt having a width of 250 mm was obtained.

  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 4 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 resistance>
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. .

<Evaluation of image>
Each belt was mounted on an intermediate transfer type color laser printer using the intermediate transfer belt shown in FIG. 3, and a printing test was conducted. About the printed image, the image defect by the wrinkle of a belt was evaluated. The case where no image defect occurred was indicated as ◯, and the case where the image occurred was indicated as x. Further, the image characteristics (color unevenness) of the printed image were evaluated by visual observation. Further, the surface of the belt after the 5000-sheet printing test was visually observed to evaluate the surface damage characteristics. The case where there was no flaw was marked with ◯, and the case where it was generated was marked with ×.

＊１）ＰＢＮ：帝人化成（株）製 ＴＱＢ−ＯＴ
＊２）ポリエーテルエステルアミド：三光化学（株）製 サンコノール ＴＢＸ−６５
＊３）ＰＢＴ：ポリプラスチックス（株）製 ジュラネックス８００ＦＰ
＊４）ポリエステルエラストマー：東洋紡（株）製 ペルプレンＥＮ−５０００
＊５）カルボジイミド化合物：日清紡（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（株）製、デンカブラック粒状

* 1) PBN: TQB-OT manufactured by Teijin Chemicals Ltd.
* 2) Polyetheresteramide: Sankonol TBX-65 manufactured by Sanko Chemical Co., Ltd.
* 3) PBT: DURANEX 800FP manufactured by Polyplastics Co., Ltd.
* 4) Polyester elastomer: Perprene EN-5000 manufactured by Toyobo Co., Ltd.
* 5) Carbodiimide compound: Carbodilite E pellets manufactured by Nisshinbo Co., Ltd. * 6) Carbon black: Denka black granular, manufactured by Electrochemical Co., Ltd.

  As shown in Tables 1 to 4 above, in the belts of the examples, a good image is obtained at a lower cost because the blending amount of the conductive agent is small, and more favorable belt characteristics (tensile elastic modulus, surface It was confirmed that the scratch characteristics were obtained. In contrast, in the belts of Comparative Examples 1 and 2, color unevenness occurred because carbon black was used for the surface layer. Further, since the belt of Comparative Example 3 has a large surface layer ratio, the elastic modulus is lowered and image defects due to wrinkles occur, and the belt of Comparative Example 4 has a large amount of ionic conductive agent added to the surface layer, and thus has a surface damage characteristic. Unfortunately, since the belt of Comparative Example 5 has a large proportion of the surface layer and the addition amount of the ionic conductive agent, image defects due to a decrease in elastic modulus and surface damage characteristics deteriorated. Further, the belt of Comparative Example 6 is a single layer belt using carbon black as a conductive agent, and color unevenness occurs. The belt of Comparative Example 7 is a single layer belt using an ionic conductive agent as a conductive agent. The amount of the conductive agent for satisfying the necessary resistance was large, and the elastic modulus was lowered. Furthermore, although the belt of Comparative Example 8 was set so that the surface layer was 1 μm, the molding was not stable and the belt could not be obtained.

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 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)
100 conductive endless belt 101 base layer 102 surface layer

Claims (5)

In an endless belt shape used in an image forming apparatus, in a conductive endless belt having a laminated structure including at least a base layer and a surface layer sequentially from the inside,
The base layer and the surface layer are mainly composed of a thermoplastic resin and / or a thermoplastic elastomer,
The base layer is obtained by adding carbon black to the resin component of the base layer,
The surface layer is formed by adding 10 parts by mass or less of an ionic conductive agent to 100 parts by mass of the resin component of the surface layer,
A conductive endless belt, wherein the thickness of the surface layer is 2 μm or more, and the ratio of the thickness of the surface layer to the total thickness of the conductive endless belt is 15% or less.   The conductive endless belt according to claim 1, wherein the surface layer contains 3 to 9 parts by mass of an ionic conductive agent with respect to 100 parts by mass of the resin component of the surface layer.   The conductive endless belt according to claim 1, wherein the surface layer is mainly composed of polybutylene naphthalate.   The conductive endless belt according to any one of claims 1 to 3, wherein the base layer is mainly composed of polybutylene terephthalate or a blend of polybutylene terephthalate and a polyester elastomer.   The conductive endless belt according to any one of claims 1 to 4, wherein a tensile elastic modulus of the entire conductive endless belt is 1600 MPa or more.

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