JP2007328165A - Conductive endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive endless belt which prevents toner from remaining on a surface thereof, and then exhibits further excellent transfer performance, and which provides good images even in long-term use. <P>SOLUTION: The conductive endless belt is used for an intermediate transfer member which is disposed between an image forming element and a recording medium, is circularly driven by a driving member, transfers a toner image formed on a surface of the image forming element onto a surface thereof once, holds the toner image, and transfers it onto the recording medium. A layer 100 making a surface of the belt has a thermoplastic resin as a principal component and powder 101 having a smaller diameter than the particle diameter of toner is embedded in a surface of the thermoplastic resin-based layer 100 in an at least partly exposed state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a 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 laser beam printer (LBP) or an electrostatic recording apparatus. The present invention relates to a conductive endless belt (hereinafter also simply referred to as “belt”) used when transferring a toner image formed by supplying a developer to 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 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 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.

Patent Document 1 discloses thermoplastic polyamide (PA), acrylonitrile-butadiene-styrene (ABS) resin, thermoplastic polyacetal (POM), any two or more polymer alloys or polymer blends thereof, and these One type selected from the group consisting of a polymer alloy or polymer blend of any one or more of them and a thermoplastic resin, and a fluororesin as a base resin, and a polymeric ionic conductive agent is added. A conductive endless belt is disclosed. Further, Patent Document 2 discloses a technique in which an inorganic pigment such as titanium oxide or silica is contained in a toner receiving layer of an electrophotographic image transfer object for the purpose of clearing the image.
JP 2004-272210 A (Claims etc.) Japanese Patent Laying-Open No. 2005-92097 (Claims etc.)

  However, among the above, in the intermediate transfer type image forming apparatus, the toner is accumulated on the intermediate transfer member and the image is transferred, so that the toner may remain on the surface by repeated use. There is a problem in that such residual toner is fused to the belt surface during endurance and causes image defects. Also in the tandem transfer system, the toner adhering to the transfer abnormality such as position detection or paper jam may remain on the belt and cause the same problem.

  On the other hand, according to the technique disclosed in Patent Document 1, a belt having excellent toner releasability in addition to belt performance such as bending durability can be obtained. As the required performance increases, it is required to further improve the transfer capability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a conductive endless belt that prevents toner from remaining on the belt surface, is more excellent in transferability, and can obtain a good image even during durable use.

  As a result of intensive studies to solve the above problems, the present inventors have improved the surface properties of the belt by embedding a powder having a diameter smaller than the toner particle size on the belt surface, and the toner on the belt surface. As a result, it has been found that transferability can be improved as compared with the prior art, and the present invention has been completed.

That is, the 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 onto its surface. In the conductive endless belt for the intermediate transfer member that holds the transfer and transfers it to the recording medium,
The belt surface layer is composed mainly of a thermoplastic resin, and a powder smaller than the toner particle diameter is embedded with at least a part of the entire surface of the layer composed mainly of the thermoplastic resin exposed. It is characterized by being.

Further, another conductive endless belt of the present invention is configured such that a recording medium held by electrostatic attraction is circulated by a driving member and conveyed to four types of image forming bodies, and each toner image is sequentially transferred to the recording medium. In tandem transfer and transfer endless belts for transfer,
The belt surface layer is composed mainly of a thermoplastic resin, and a powder smaller than the toner particle diameter is embedded with at least a part of the entire surface of the layer composed mainly of the thermoplastic resin exposed. It is characterized by being.

The belt of the present invention preferably has a single layer structure of a layer mainly composed of the thermoplastic resin. In the present invention, hydrophobic silica can be preferably used as the powder, and the average particle size of the powder is preferably in the range of 0.5 to 6.0 μm. Further, the thermoplastic resin is preferably one containing at least one of a thermoplastic polyester elastomer and a thermoplastic polyamide, and particularly has a volume resistivity in the range of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. Some are preferred.

  According to the present invention, the above configuration realizes a conductive endless belt that prevents toner from remaining on the belt surface, has better transferability, and can obtain a good image even during durable use. It became possible to do.

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 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.

  FIG. 1 shows an enlarged partial sectional view of the vicinity of the surface of the conductive endless belt of the present invention. In the belt of the present invention, the layer 100 forming the belt surface has a thermoplastic resin as a main component, and as shown in the drawing, at least a part is exposed over the entire surface of the layer 100 having the thermoplastic resin as a main component. In this state, a powder 101 having a diameter smaller than the toner particle diameter is embedded.

  Thus, when the belt of the present invention is incorporated in an image forming apparatus and used, the toner substantially comes into contact with the powder 101 instead of the resin layer 100, and the particle size of the powder 101 is the toner particle size. Therefore, the toner does not adhere to or remain on the belt surface. On the other hand, even if the powder 101 is present on the belt surface, it does not affect the electrical characteristics of the belt, so that other belt properties are not impaired.

  Therefore, in the present invention, the powder 101 preferably covers the entire surface of the belt so as not to have a gap equal to or larger than the toner particle size. As a method for forming such a surface state, after forming the belt body by extrusion molding or the like, the powder 101 is spread so as to cover the belt surface without gaps, and the resin layer 100 is melted by hot pressing. Then, a method of fixing the powder 101 in an embedded state on the surface by cooling is effective. Further, depending on the type of the powder 101, a structure in which the powder 101 is embedded in the belt surface may be formed by kneading into the resin composition constituting the resin layer 100 and bleeding out by heating. Is possible.

  The powder 101 is not particularly limited as long as it has a diameter smaller than the toner particle diameter and has heat resistance capable of withstanding the above-described production method. For example, hydrophobic silica, polyethylene, polypropylene, polytetrafluoroethylene Etc., and hydrophobic silica is preferably used. The shape of the powder 101 is not particularly limited, but a spherical shape or an oval shape is preferable. Further, the particle diameter is preferably in the range of an average particle diameter of 0.5 to 6.0 μm. If the average particle size is too small, it is difficult to embed the powder to such an extent that the surface is partially exposed, and if the average particle size is too large, the toner will be embedded in the powder. It is not preferable.

  Furthermore, the amount of powder 101 embedded, that is, the ratio of the portion embedded in the belt for each powder 101 is preferably about 1 to 80% of the total volume of powder 101. If the embedment amount is less than 1%, the powder 101 tends to fall off from the belt surface. On the other hand, if it exceeds 80%, the exposure amount from the belt surface is too small and the intended effect of the present invention may not be obtained. There is. In addition, this amount of embedding can be evaluated by, for example, microscopic observation of the belt cross section.

  In the present invention, only the point that the powder 101 is embedded in the belt surface is important, and the other points are not particularly limited. For example, as the resin constituting the belt body, the resin layer 100 forming the belt surface needs to be mainly composed of a thermoplastic resin, but the other inner layers are made of a thermosetting resin. The main component may be used. Therefore, the belt of the present invention has a structure in which a layer mainly composed of a thermoplastic resin and another layer are laminated even if the belt has a single layer structure composed mainly of a thermoplastic resin. Or any of them.

The thermoplastic resin that can be used in the present invention is not particularly limited and may be any material conventionally used as a belt material. In particular, it is preferable to use a thermoplastic resin having a volume resistivity in the range of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. Specifically, for example, a thermoplastic polyalkylene naphthalate resin (for example, polyethylene naphthalate (PEN) resin, PBN resin, etc.) or a thermoplastic polyalkylene terephthalate resin (for example, polyethylene terephthalate (PET) resin, glycol-modified PET (PETG)). ) Resin, PBT resin, etc.), 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 polyarylate (PAR), thermoplastic polycarbonate (PC), polyester, polyamide, polyether, Various thermoplastic elastomers such as reolefin-based, polyurethane-based, styrene-based, acrylic-based, polydiene-based and the like can be mentioned. Preferably, since the powder 101 is easily embedded, thermoplastic polyester-based elastomer (TPEE). Alternatively, at least one of PA is used.

  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. .

  The belt of the present invention is blended with a conductive material in order to adjust the conductivity. 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.

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

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 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 Sanconol TBX-310 (manufactured by Sanko Chemical Co., Ltd.) is commercially available.

  When a polymer ion conductive agent is used as the conductive material, a compatibilizing agent may be added in order to increase the compatibility between the base resin and the polymer ion conductive agent.

  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 50 parts by weight or less, for example 1 to 50 parts by weight, particularly 1 to 30 parts by weight, especially 5 to 20 parts by weight for each layer, and for the electronic conductive agent with respect to 100 parts by weight of the resin component. Parts by weight. Moreover, about an ion conductive agent, it is the range of 0.01-20 weight part normally with respect to 100 weight part of resin components, Especially 0.1-10 weight part. Furthermore, about a polymeric ion electrically conductive agent, it is 1-100 weight part normally with respect to 100 weight part of resin components, Preferably it is about 5-50 weight part. In the present invention, it is particularly preferable to use carbon black as the conductive material and add 5 to 20 parts by weight with respect to 100 parts by weight of the resin component.

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

  The 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 shown in FIG. A fitting portion that fits with a fitting portion (not shown) formed on the drive member may be formed, and the conductive endless belt of the present invention is provided with such a fitting portion and drives this. Shifting in the width direction of the conductive endless belt can be prevented by running with a fitting portion (not shown) provided on the member.

  In this case, the fitting portion is not particularly limited, but, as shown in FIG. 5, 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 protrusion as a fitting part was shown in Fig.5 (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. 5 (b)), or may be provided at the center in the width direction of the belt. Further, a groove along the circumferential direction (rotation direction) of the belt is provided as the fitting portion instead of the convex strip shown in FIG. 5, 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 belt main body of the conductive endless belt of the present invention can be preferably manufactured by extrusion molding of a resin composition containing the above base resin and conductive material. By embedding in the belt, the belt of the present invention can be obtained. Specifically, the extrusion of the belt body is performed by, for example, kneading a resin composition composed of a base material and a functional component such as a conductive material with a biaxial kneader, and using the obtained kneaded material using an annular die. Can be performed by extrusion molding. Alternatively, a powder coating method such as electrostatic coating, a dip method, or a centrifugal casting method can also be suitably employed.

Hereinafter, the present invention will be described in more detail with reference to examples.
Conductive endless belts of Examples and Comparative Examples were prepared with the formulations shown in Table 1 below. Specifically, first, each compounding component is melt-kneaded by a biaxial kneader, and the obtained kneaded product is extruded using a predetermined annular die, whereby the inner diameter is 220 mm, the thickness is 100 μm, and the width is 250 mm. A belt body having The kneading / extrusion molding temperature was 250 ° C. Next, except for Comparative Example 1, hydrophobic silica having an average particle size shown in Table 1 below was spread on the surface without any gaps, and the resin layer on the surface was melted by hot pressing at 200 ° C., and then cooled. As a result, hydrophobic silica was embedded in the entire surface to obtain a conductive endless belt. In addition, all compounding quantities in the following Table 1 represent “parts by weight”.

  The belts of the obtained examples and comparative examples were evaluated according to the following procedures. These results are shown together in Tables 1 to 3 below together with the value of the embedded amount of hydrophobic silica evaluated by microscopic observation of the belt cross section. “Embedded amount 0%” means a state in which hydrophobic silica is in close contact with the resin layer surface.

<Measurement of volume resistance>
At a temperature of 23 ° C. and a relative humidity of 50%, the volume resistance value Rv1000V when a voltage of 1000V was applied was measured using a resistance chamber made of ADVANTEST, a resistance meter R8340A connected to a sample chamber R12704A. The average value of the values measured at 20 points with a 20 mm pitch in the circumferential direction was obtained.

<Transferability>
The belts of the examples and comparative examples were mounted on the intermediate transfer type image forming apparatus shown in FIG. 3, and the transferability was evaluated based on the amount of toner remaining on the belt when the image was output. The average particle size of the toner used at this time was 10 μm. As a result of visual judgment, a case where the amount of residual toner is large is “X”, and a case where the amount is small is “◯”. Similarly, the transferability at the time of durable use was also evaluated by the amount of residual toner after durable use of 1000 sheets.
These results are also shown in Table 1 below.

＊１）ＴＰＥＥ：東洋紡（株）製、ペルプレンＥ４５０Ｂ
＊２）ＰＢＴ：ポリプラスチックス（株）製、ジュラネックス５００ＦＰ
＊３）ＰＡ１２：ダイセル・ヒュルス（株）製、ダイアミドＬ１９４０
＊４）カーボンブラック：電気化学工業（株）製、デンカブラック粒状
＊５）疎水性シリカ：東ソー・シリカ（株）製、ニップシールＳＳ−２０

* 1) TPEE: manufactured by Toyobo Co., Ltd., Perprene E450B
* 2) PBT: Polyplastics Co., Ltd., Juranex 500FP
* 3) PA12: manufactured by Daicel Huls Co., Ltd., Daiamide L1940
* 4) Carbon black: Denka Black granular, manufactured by Denki Kagaku Kogyo Co., Ltd. * 5) Hydrophobic silica: NIPSEAL SS-20, manufactured by Tosoh Silica Co., Ltd.

  As shown in Table 1 above, in the belts of the examples in which hydrophobic silica having a predetermined particle diameter is embedded on the surface, there is no residual toner in both initial and durable use, and good transferability is ensured. You can see that On the other hand, in the belt of Comparative Example 1 in which the hydrophobic silica was not embedded, the toner remained in both the initial stage and the endurance use, and as a result, the transferability was insufficient. In addition, the belt of Comparative Example 2 that has hydrophobic silica on the surface but is not substantially embedded can prevent toner from remaining in the initial stage and has good transferability. Later, it can be seen that since the hydrophobic silica has fallen off from the belt surface, the effect of preventing residual toner cannot be obtained, and as a result, the transferability is deteriorated.

It is an expanded partial sectional view showing the surface neighborhood of the conductive endless belt concerning one embodiment of the present 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 according to 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 according to the present invention. FIG. 10 is a schematic view showing an intermediate transfer device using another intermediate transfer member as still another example of the image forming apparatus according to the present invention. It is width direction sectional drawing of the electroconductive endless belt which concerns on one embodiment of this 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, 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 Layer forming belt surface 101 Powder

Claims (7)

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
The belt surface layer is composed mainly of a thermoplastic resin, and a powder smaller than the toner particle diameter is embedded with at least a part of the entire surface of the layer composed mainly of the thermoplastic resin exposed. A conductive endless belt characterized by being made. 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
The belt surface layer is composed mainly of a thermoplastic resin, and a powder smaller than the toner particle diameter is embedded with at least a part of the entire surface of the layer composed mainly of the thermoplastic resin exposed. A conductive endless belt characterized by being made.   The conductive endless belt according to claim 1, wherein the conductive endless belt has a single-layer structure of a layer mainly composed of the thermoplastic resin.   The conductive endless belt according to claim 1, wherein the powder is hydrophobic silica.   The conductive endless belt according to any one of claims 1 to 4, wherein an average particle diameter of the powder is in a range of 0.5 to 6.0 µm.   The conductive endless belt according to any one of claims 1 to 5, wherein the thermoplastic resin contains at least one of a thermoplastic polyester elastomer and a thermoplastic polyamide. The conductive endless belt according to any one of claims 1 to 6, wherein a volume resistivity of the thermoplastic resin is in a range of 1 x 10 ⁸ to 1 x 10 ¹³ Ωcm.

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