JP2005257849A - Conductive endless belt, its production method and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive endless belt which realizes excellent infrared reflectance by improving the flatness of the surface and enhancing the brilliance and can perform an exact driving control while keeping the friction between the conductive endless belt and a driving member in a prescribed level as for the back surface, and to provide a production method of the conductive endless belt and an image forming apparatus using the conductive endless belt. <P>SOLUTION: In the conductive endless belt for transfer and conveyance of the tandem system, a recording medium held by electrostatic adsorption is circulatively driven by a driving member and is conveyed to four kinds of image forming bodies and respective toner images are successively transferred on the recording medium. The conductive endless belt consists of a single layer principally comprising thermoplastic resin and has the back surface formed roughly more than the surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive endless belt (hereinafter, also simply referred to as a “belt”), a manufacturing method thereof, and an image forming apparatus using the same, and more specifically, electrophotographic devices such as copying machines and printers, electrostatic recording devices, and the like. In the electrostatic recording process in, when a toner image formed by supplying 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 is transferred to a recording medium such as paper TECHNICAL FIELD The present invention relates to a conductive endless belt used in the present invention, a manufacturing method thereof, 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 yellow Y, magenta M, cyan C, and black B toners. The toner is 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 28 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 photosensitive 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.

  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 an endless belt-like conductive endless belt such as the intermediate transfer member, a semiconductive resin film belt and a rubber belt provided with a fiber reinforcement have been mainly used, and recently, the cost is particularly low. From the above advantages, many resin film belts with various improvements have been proposed. For example, the present applicant has also proposed, in Patent Document 1, a conductive endless belt in which strength and dimensional stability are improved by using a predetermined thermoplastic resin as a base material. Patent Document 2 describes an endless resin belt having a three-layer structure in which the reflectance and surface roughness of the inner surface and / or outer surface are defined.
JP 2002-132053 A (Claims etc.) JP 2003-251647 A (Claims etc.)

  As described above, various studies have been made on the conductive endless belt, but in recent years, the driving of the belt has been performed as the accuracy of the image is increased and the speed and size of the image forming apparatus are increased. Further improvements in braking and positioning accuracy have been demanded. In order to realize this, it has a high surface gloss that can be applied to a drive control system using infrared reflection that can detect a change in the belt size due to a temperature change and perform correction control. A belt is essential.

  However, when the smoothness is increased in order to increase the surface glossiness of the belt surface, the back surface is inevitably smoothed for manufacturing, particularly in a belt composed of a single layer. As a result, the coefficient of friction between the drive member and the belt decreases, causing a problem that slipping occurs and accurate drive control cannot be performed.

  Accordingly, the object of the present invention is to improve the smoothness and glossiness of the front surface to achieve a good infrared reflectivity and to maintain the friction with the driving member at a predetermined level on the back surface. It is an object of the present invention to provide a conductive endless belt, a method for manufacturing the same, and an image forming apparatus using the conductive endless belt, which enable easy drive control.

  As a result of intensive studies, the present inventors have found that the above-described problem can be solved by adopting the following configuration, and have completed the present invention.

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 consists of a single layer mainly composed of a thermoplastic resin, and the back surface is formed rougher than the front surface.

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 consists of a single layer mainly composed of a thermoplastic resin, and the back surface is formed rougher than the front surface.

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 consists of a single layer mainly composed of a thermoplastic resin, and the back surface is formed rougher than the front surface.

  In the belt of the present invention, the difference between the roughness of the back surface and the roughness of the surface is preferably 0.5 μm or more in Ra. The present invention is particularly effective when the surface of the drive member is made of a rubber material.

  Further, the method for producing a conductive endless belt according to the present invention is a method for producing the conductive endless belt according to the present invention described above, and when the conductive endless belt is extruded using an annular die, the belt surface of the annular die is formed. A temperature difference is provided between the surface facing the belt and the mandrel surface facing the back surface of the belt.

  Furthermore, another method for producing a conductive endless belt according to the present invention is a method for producing the conductive endless belt according to the present invention, wherein when the conductive endless belt is extruded using an annular die, The surface of the mandrel facing the back surface of the belt is roughened.

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

  According to the conductive endless belt of the present invention, with the above configuration, the smoothness of the belt surface can be improved and the glossiness can be increased, thereby providing a good infrared reflectance and driving accuracy. It is possible to obtain an excellent conductive endless belt capable of improving the above and the like. In addition, a necessary friction coefficient can be secured between the back surface of the belt and the driving member, and accurate driving control can be performed. Therefore, according to the image forming apparatus of the present invention using such a belt, it is possible to stably obtain a highly accurate image. The belt of the present invention can be easily manufactured by the manufacturing method of the present invention.

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. Are transferred to form a color image.

  The conductive endless belt of the present invention is a single layer belt composed of a single layer mainly composed of a thermoplastic resin, and is characterized in that the back surface is formed to be rougher than the front surface. That is, by changing the roughness between the front surface and the back surface of the belt and making the roughness of the back surface rougher than the surface, a desired smoothness is obtained for the surface, and thus a glossiness is obtained. For example, it is possible to ensure an appropriate friction coefficient with the driving roller 9 in FIG. 2, the driving roller 30 in FIG. 3, the driving roller 55 in FIG.

  The surface roughness Ra (arithmetic mean roughness) of the belt of the present invention is preferably 0.2 μm or less, more preferably 0.05 μm or less in order to obtain an appropriate glossiness. Thereby, the glossiness at an angle of 60 ° from the perpendicular can be 80 or more, particularly 90 or more. Further, the roughness Ra of the back surface is preferably 0.5 μm or more, more preferably 1 μm or more in order to obtain good rotation transmission from the driving member. Therefore, in the belt of the present invention, the difference between the roughness of the back surface and the roughness of the surface is preferably 0.5 μm or more in Ra.

  In the present invention, the drive member is assumed to be, for example, a drive roller whose surface is made of a rubber material, and the conductive endless belt of the present invention is, for example, ethylene propylene diene terpolymer rubber (EPDM). It can use suitably in combination with the drive roller which consists of.

  In the belt of the present invention, specific materials and other physical property values are not particularly limited as long as the above conditions regarding the roughness of the front surface and the back surface are satisfied. Can be.

  As the base resin that is the main component of the belt, a thermoplastic resin is used because extrusion is possible. Examples of such thermoplastic resins include thermoplastic polyalkylene naphthalate resins (for example, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, etc.), thermoplastic polyethylene terephthalate resins (for example, polyethylene terephthalate (PET)). ) Resin, polybutylene terephthalate (PBT) resin, etc.), thermoplastic polyamide (PA), acrylonitrile-butadiene-styrene (ABS) resin, thermoplastic polyacetal (POM), thermoplastic polyarylate (PAR), thermoplastic polycarbonate (PC) ) Etc. can be mentioned suitably. In addition, polymer alloys or polymer blends of these thermoplastic resins and thermoplastic elastomers can also be used, and by using any of these as a base material, good strength, particularly good bending durability. Can be obtained.

In the belt of the present invention, conductivity can be imparted and adjusted by adding a conductive material as a functional component to the substrate as desired. Such conductive materials include, for example, lauryltrimethylammonium, stearyltrimethylammonium, octadecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, modified fatty acid / dimethylethylammonium perchlorate, chlorate, borofluoric acid Cationic surfactants such as quaternary ammonium such as salts, sulfates, ethosulphate salts, benzyl halide salts (such as verzyl bromide and benzyl chloride); aliphatic sulfonic acids, higher alcohol sulfates, higher Anionic surfactants such as alcohol ethylene oxide addition sulfates and higher alcohol phosphates; amphoteric surfactants such as various betaines; higher alcohol ethylene oxides, polyethylene glycol fatty acid esters Le, polyhydric alcohol fatty acid ester antistatic agent such as a nonionic antistatic agents such _{as, LiCF 2 SO 2, NaClO 4} , LiBF 4, periodic table Group 1 metal salts such as NaCl; Ca (ClO ₄₎ Metal salts belonging to Group 2 of the Periodic Table such as _{2 and the} like, and those antistatic agents having one or more groups having active hydrogen (hydrogen group, carboxyl group, primary or secondary amine group, etc.) that react with isocyanate Etc. Furthermore, ions of these and complexes with polyhydric alcohols (1,4-butanediol, ethylene glycol, polyethylene glycol, propylene glycol, etc.) or derivatives thereof, or complexes with ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc. Conductive agent; conductive carbon such as ketjen black, acetylene black; carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT; carbon for oxidized color ink, pyrolytic carbon, Examples thereof include natural graphite, artificial graphite and the like; metals and metal oxides such as tin oxide, titanium oxide, zinc oxide, nickel and copper; and conductive polymers such as polyaniline, polypyrrole and polyacetylene.

  In the present invention, a polymer ion conductive agent may be used as the conductive material. Examples of such a polymer ion conductive agent include JP-A-9-227717, JP-A-10-120924, and Although what is described in Unexamined-Japanese-Patent No. 2000-327922 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, polyurethane or polyester, component (B) is an oligoethoxylated acrylate or methacrylate, oligoethoxylated for aromatic rings Styrene, polyether urethane, polyether urea, polyether amide, polyether ester amide or polyether ester, and component (C) is an alkali metal or alkaline earth metal of an inorganic or low molecular weight organic protonic acid , A lead 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 or Ca (CF ₃ SO ₃ ) ₂ etc.

Among these, as the component (B), a polymer ionic conductive agent containing a polyether amide component or a polyether ester amide component is suitable, and in addition to this, a low molecular ionic conductive agent component as the component (C). It is preferable to contain. 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 nylon 12 or nylon 6 are particularly preferable. As a component (B), a polymer ion conductive agent containing NaClO ₄ as a low molecular ion conductive agent component of component (C) is particularly suitable. Such suitable polymer ion conductive agents are commercially available as Irgastat (registered trademark) P18 and Irgastat (registered trademark) P22 (both manufactured by Ciba Specialty Chemicals, Inc.) and Perestat NC6321 (manufactured by Sanyo Chemical Co., Ltd.). It can be obtained.

  The addition amount of these conductive materials is preferably 0.01 to 30 parts by weight, more preferably about 0.1 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin as a main component.

  Further, when the above polymer ion conductive agent is used in the conductive endless belt of the present invention, a compatibilizing agent is added in order to improve the compatibility between the thermoplastic resin as the base material and the polymer ion conductive agent. May be. 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), olefinic graft copolymer, maleated polyolefin, SEBS and its maleated product, oxazoline group-containing styrene-based or acrylonitrile-styrene-based polymer, maleated EPDM, maleic PE, maleated PP, maleated EVA, styrene / maleic anhydride copolymer, SAN grafted EPDM, reactive polystyrene, polycaprolactone-b-polystyrene, reactive styrene acrylic Ronitrile copolymer, imidized polyacrylate, ethylene / glycidyl methacrylate acrylic acid copolymer, chlorinated polyethylene, reactive phenoxy, silane compound, peroxide polymer, polycaprolactone, EVA / EPDM / polyolefin graft polymer, etc. Are abbreviated as 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 may be used in a total amount of 100 parts by weight of the base material and the polymeric ion conductive agent. The addition of 0.1 to 20 parts by weight preferably improves the compatibility of the two, enables uniform and good dispersion of the polymer ion conductive agent on the base material, and provides a high-performance conductive endless belt. Can be obtained.

  In addition to the above-described components, other functional components can be appropriately added to the belt. For example, various fillers, coupling agents, antioxidants, lubricants, surface treatment agents, pigments, An ultraviolet absorber, an antistatic agent, a dispersing agent, 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 thickness of the conductive endless belt of the present invention is appropriately selected according to the form of the transfer / conveying belt or the intermediate transfer member, but is preferably in the range of 50 to 200 μm.

  Further, the 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.

  The conductive endless belt of the present invention is obtained by kneading a functional component such as a thermoplastic resin as a base material and a conductive material with a biaxial kneader, and extruding the obtained kneaded product using an annular die. It can be continuously manufactured by molding (see FIG. 6). At this time, a temperature difference is provided between the surface A of the annular die 201 facing the belt surface and the surface B of the mandrel 202 facing the belt back surface. Thus, the difference in roughness according to the present invention can be easily formed. Specifically, for example, by using cooling water or the like, the temperature of the surface B of the mandrel 202 facing the back surface of the belt is made lower than the temperature of the surface A corresponding to the surface, so that the filler is applied to the back surface on the low temperature side. As a result, the back surface of the belt 100 can be made rougher and the surface can be made smoother. In addition, the code | symbol 203 in FIG. 6 shows a screw.

  In addition, a method in which the mandrel surface B facing the belt back surface of the annular die is previously roughened may be used. In this case, the mandrel surface B is roughened. A desired roughness difference can be provided between the front surface and the back surface of the belt 100. In addition, by performing multilayer extrusion only by changing the filler content, the filler can be unevenly distributed in the same manner as described above, thereby forming a difference in roughness between the front surface and the back surface of the belt 100. It is also possible. Further, after forming the front and back surfaces with the same surface roughness by a powder coating method such as normal extrusion molding or electrostatic coating, dipping method or centrifugal casting method, 2 by sandblasting or thermal transfer of the embossed surface. You may use the method of roughening a back surface by giving a next process.

  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 driving roller or driving gear for rotating the intermediate transfer member 20 of the present invention. The application conditions such as application of weighting alternating current can be selected as appropriate.

Examples 1 and 2 and Comparative Example Thermoplastic polybutylene terephthalate resin (manufactured by Teijin Chemicals Ltd., trade name: TQB-OT) and thermoplastic polyethylene terephthalate resin (manufactured by Unitika Ltd., trade name: SA1206) ) 20 parts by weight and 15 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were dissolved and kneaded by a twin-screw kneader, and the resulting kneaded product was extruded to obtain an inner diameter of 245 mm and a thickness of 0 A conductive endless belt having a width of 1 mm and a width of 250 mm was obtained.

  When the roughness of the obtained belt was examined, it was almost the same Ra = 0.02 μm on the front surface and the back surface. In order to investigate the influence of the belt roughness on the driving performance, only the back surface of this belt is sandblasted, and the surface roughness of the back surface is Ra = 2.0 μm (Example 1) and Ra = 1.0 μm (Example 2). ) Were produced and compared with a belt not subjected to treatment (comparative example) by the following measurement.

Measurement of dynamic friction coefficient The dynamic friction coefficient is measured in accordance with JIS-K7125 using a surface property measuring instrument (HEIDON type 14DR, manufactured by Shinto Kagaku Co., Ltd.) as a measuring instrument, and kept at a room temperature of 23 ° C. and a humidity of 50%. I went in a drenched environment. Specifically, a movable plate was applied by applying a load of 100 g to a fixed plate on which a rubber sheet (EPDM) having a thickness of 1.5 mm was attached, and attaching a conductive resin film cut out from the belts of the examples and comparative examples. The dynamic friction coefficient between the back surface of the belt and the rubber sheet was measured by placing on the plate and sliding the movable plate at a speed of 100 mm / min.

Driving force measurement (slip evaluation)
Slip between the driving roller 101 and the belt 100 was evaluated using an apparatus shown in FIG. 5 simulating a printer driving system. In the illustrated apparatus, the belt 100 is stretched and rotated between a driving roller 101 and an idler roller 102, and the tension applied to the belt 100 is adjusted by changing the distance between the two rollers using a load cell. be able to. Both rollers are made of rubber (EPDM) and have a diameter of 30 mm. The belt speed was 120 mm per second. In this apparatus, the belt tension was gradually increased, and the tension at which the rotation stopped was measured to obtain a driving force. The greater the tension, the greater the driving force.
These results are shown in Table 1 below together with the value of the surface roughness Ra for each of the front surface and the back surface.

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. 5 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 still another example of the image forming apparatus of the present invention. It is the schematic which shows the driving force measuring apparatus in an Example. It is a schematic explanatory drawing of extrusion molding using an annular die.

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 drive roller 102 idle roller 201 annular die 202 mandrel 203 screw

Claims (8)

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
A conductive endless belt comprising a single layer mainly composed of a thermoplastic resin, the back surface being formed rougher than the front surface. 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
A conductive endless belt comprising a single layer mainly composed of a thermoplastic resin, the back surface being formed rougher than the front surface. 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,
A conductive endless belt comprising a single layer mainly composed of a thermoplastic resin, the back surface being formed rougher than the front surface.   The conductive endless belt according to any one of claims 1 to 3, wherein a difference between the roughness of the back surface and the roughness of the surface is 0.5 µm or more in Ra.   The conductive endless belt according to claim 1, wherein a surface of the driving member is made of a rubber material.   A method for producing a conductive endless belt according to any one of claims 1 to 5, wherein when the conductive endless belt is extruded using an annular die, a surface of the annular die facing the belt surface; A method for producing a conductive endless belt, characterized in that a temperature difference is provided between the mandrel surface facing the back surface of the belt.   A method for producing a conductive endless belt according to any one of claims 1 to 5, wherein when the conductive endless belt is extruded using an annular die, the mandrel facing the back surface of the belt as the annular die. A method for producing a conductive endless belt, characterized by using a roughened surface.   An image forming apparatus using the conductive endless belt according to claim 1.

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