JP5013766B2 - Conductive endless belt and image forming apparatus using the same - Google Patents

Description

  The present invention supplies a developer to the surface of an image forming body such as a latent image holding body holding an electrostatic latent image on the surface in an electrostatic recording process in an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus. The present invention relates to a conductive endless belt (hereinafter also simply referred to as “belt”) used when transferring a toner image formed in this way onto a recording medium such as paper, 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 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 a tandem intermediate transfer method that combines a tandem method and an intermediate transfer method. FIG. 4 illustrates an image forming apparatus of a tandem intermediate transfer system that forms a color image using an endless belt-like tandem intermediate transfer member.

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

  In the figure, reference numeral 55 denotes a driving roller or tension roller for circulatingly driving the tandem intermediate transfer member 50, reference numeral 56 denotes a recording medium feeding roller, reference numeral 57 denotes a recording medium feeding device, and reference numeral 58 denotes a recording medium. 3 shows a fixing device for fixing the image by heating or the like. Reference numeral 59 denotes a power supply device (voltage applying means) for applying a voltage to the tandem intermediate transfer member 50. The power supply device 59 transfers the toner image from the photosensitive drums 52a to 52d to the tandem intermediate transfer member 50. In this case, the polarity of the applied voltage can be reversed between the case where the image is transferred from the tandem intermediate transfer member 50 onto the recording medium 53.

  As the conductive endless belt used as the transfer conveyance belt 10, the intermediate transfer member 20, the tandem intermediate transfer member 50, etc. in the various image forming apparatuses described above, conventionally, a semiconductive resin film belt and a fiber reinforcement have been provided. Rubber belts are mainly used. Among these, as the resin film belt, for example, Patent Document 1 discloses a conductive endless belt using a thermoplastic polyalkylene naphthalate resin, or a polymer alloy or a polymer blend of the thermoplastic polyalkylene naphthalate resin and another thermoplastic resin as a base material. Are listed.

Patent Document 2 describes a conductive seamless belt using a polyester-based elastomer having a melting point in the range of 160 to 210 ° C. as a conductive base layer. Patent Document 3 discloses a Young's modulus of 1200 MPa or more. A seamless belt made of a thermoplastic polyester elastomer is described.
JP 2002-132053 A (Claims etc.) Japanese Patent Laid-Open No. 2000-62993 (claims, etc.) JP 2004-258153 A (Claims etc.)

  The conductive endless belt used in the above various image forming apparatuses has a high mechanical strength that can withstand repeated continuous use in terms of mechanism, and also has various characteristics according to the use environment in a well-balanced manner. Is required. According to the technique described in Patent Document 1, a conductive endless belt having a predetermined good strength can be obtained. In this case, since the elastic modulus is high, elongation does not occur when the belt rotates, and image shift occurs. Although not sufficient in terms of bending resistance, there were cases where belt durability was problematic. In addition, the belt described in Patent Document 2 is excellent in durability because it uses an elastomer having a low melting point, but on the other hand, image shift due to elongation or image deterioration due to deformation in a high temperature and high humidity environment occurs. There was a problem.

  Therefore, the object of the present invention is to have physical properties that can withstand repeated continuous use in terms of mechanism, in particular, bending durability and set resistance, as well as appropriate volume resistance and elastic modulus, in image misalignment and high temperature and high humidity environments. It is an object of the present invention to provide a conductive endless belt and an image forming apparatus using the conductive endless belt which do not cause a problem of image deterioration due to deformation of the belt.

  As a result of intensive studies, the present inventors have found that the above-described problems 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 mainly comprises at least one thermoplastic polyester elastomer having a crystal melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and has a tensile elastic modulus of 800 MPa or more. is there.

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 mainly comprises at least one thermoplastic polyester elastomer having a crystal melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and has a tensile elastic modulus of 800 MPa or more. is there.

Further, 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 mainly comprises at least one thermoplastic polyester elastomer having a crystal melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and has a tensile elastic modulus of 800 MPa or more. is there.

  In the present invention, the thermoplastic polyester-based elastomer preferably includes two or more types. Moreover, the addition amount of the carbodiimide compound is preferably in the range of 0.05 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer. Furthermore, the belt of the present invention preferably contains a thermoplastic polyester resin as a base resin within a range of 5 to 49% by weight of the total base resin. As the thermoplastic polyester resin, Polybutylene terephthalate (PBT) resin and polybutylene naphthalate (PBN) resin are preferred.

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

  According to the present invention, the use of a thermoplastic polyester elastomer having a higher melting point than the conventional belt base material and the incorporation of a carbodiimide compound improves the elastic modulus of the belt, and improves durability and environmental characteristics. In addition, it is possible to provide a high-performance conductive endless belt that does not cause problems such as conventional image misalignment, and an image forming apparatus using the same.

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 mainly contains at least one polyester-based elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and has a tensile elastic modulus of 800 MPa or more. Is characterized in that it is 800 to 2500 MPa.

  The thermoplastic polyester elastomer used as the belt base resin in the present invention is not particularly limited as long as it has a crystal melting point of 210 ° C. or higher, and is a polyester-polyester type using a polyester for the hard segment and the soft segment, and Both polyester-polyether type polyesters using hard segments and polyethers and soft segments can be preferably used. In addition, although the hard segment of the polyester-based elastomer is generally used mainly with polybutylene terephthalate (PBT) or polybutylene naphthalate (PBN), any one can be used in the present invention. . In the present invention, it is particularly preferable to use two or more kinds of such thermoplastic polyester elastomers. A thermoplastic polyester elastomer having a crystal melting point of 210 ° C or higher is used in combination with a thermoplastic polyester elastomer having a crystal melting point of 210 ° C or higher. However, in this case, the addition amount of the thermoplastic polyester elastomer having a crystal melting point of less than 210 ° C. is 20% by weight or less of the total amount of both elastomers, for example, about 5 to 15% by weight. If the amount of the thermoplastic polyester elastomer having a crystal melting point of less than 210 ° C. is too large, the elastic modulus of the belt becomes insufficient and the intended effect of the present invention may be impaired.

  In the present invention, the thermoplastic polyester elastomer can be used alone as a base resin, but the thermoplastic polyester elastomer and the thermoplastic polyester resin can be blended and used as a base resin. In this case, the blending amount of the thermoplastic polyester resin is 5 to 49% by weight, particularly 10 to 49% by weight of the total base resin. By using a blend of a thermoplastic polyester elastomer and a thermoplastic polyester resin as the base resin, a belt with higher elasticity can be obtained. However, if the blending amount of the thermoplastic polyester resin exceeds 49% by weight of the total base resin, it is not preferable because the bending resistance of the belt is lowered.

  Specific examples of the thermoplastic polyester resin include thermoplastic polyalkylene naphthalate resins (for example, polyethylene naphthalate (PEN) resin, PBN resin, etc.) and thermoplastic polyalkylene terephthalate resins (for example, polyethylene terephthalate ( (PET) resin, glycol-modified PET (PETG) resin, PBT resin, etc.), and the like. Preferably, PBN resin or PBT resin is used.

  Since the thermoplastic polyester elastomer and thermoplastic polyester resin used in the present invention are likely to cause a decrease in molecular weight due to hydrolysis during molding and heating, in the present invention, by adding a compound having a carbodiimide group, A carboxyl group and a hydroxyl group generated by hydrolysis are caused to undergo a crosslinking reaction to prevent a decrease in molecular weight. Thereby, not only the melt stability is improved and high dimensional accuracy is obtained, but also the embrittlement of the belt can be prevented, and the crack resistance of the belt at the time of durability can be improved. Such carbodiimide compounds are easily available on the market, and examples thereof include trade name: Carbodilite manufactured by Nisshinbo Industries, Inc. The carbodiimide compound can also be used in the form of a masterbatch pellet or the like, for example, Nisshinbo Co., Ltd. trade name: Carbodilite E pellet, B pellet or the like can be suitably used.

  The amount of the carbodiimide compound added is preferably 0.05 to 30 parts by weight, more preferably 0.1 parts per 100 parts by weight of the total amount of the belt base resin in order to obtain the desired effect of the present invention. Within the range of -5 parts by weight.

  Further, the conductive agent is not particularly limited, and an electronic conductive agent, an ionic conductive agent, or the like can be 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.

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

  The compounding amount of the electronic conductive agent is usually 100 parts by weight or less, for example, 1 to 100 parts by weight, particularly 1 to 80 parts by weight, especially 5 to 50 parts by weight with respect to 100 parts by weight of the base material. Moreover, the compounding quantity of an ionic conductive agent is 0.01-10 weight part normally with respect to 100 weight part of resin, Especially the range of 0.05-5 weight part. In the present invention, it is particularly preferable to add 5 to 30 parts by weight of carbon black as a conductive agent with respect to 100 parts by weight of the base material.

  In the conductive endless belt of the present invention, other functional components can be appropriately added in addition to the above-described conductive filler, as long as the effects of the present invention are not impaired. For example, various fillers, cups A ring 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 thickness of the conductive endless belt of the present invention is appropriately selected according to the form of the transfer / conveying belt or the intermediate transfer member, but is preferably in the range of 50 to 200 μm. The surface roughness is preferably 10 μm or less, particularly 6 μm or less, more preferably 3 μm or less in terms of JIS 10-point average roughness Rz. Furthermore, it is preferable to adjust the volume resistivity within a range of 10 ² Ω · cm to 10 ¹³ Ω · cm.

  Further, the conductive endless belt of the present invention has a surface on the side in contact with a driving member such as the driving roller 9 or the driving roller 30 of FIG. 3 in the image forming apparatus 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. The belt can be prevented from shifting in the width direction by being fitted with a fitting portion (not shown) provided on the member and running.

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

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

  Further, as the image forming apparatus of the present invention using the conductive endless belt of the present invention, the tandem system shown in FIG. 2, the intermediate transfer system shown in FIG. 3, or the tandem intermediate transfer system shown in FIG. Although the thing can be illustrated, it is not limited to these. In the case of the apparatus shown in FIG. 3, a voltage can be appropriately applied from the power source 61 to the 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.

Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-11 and Comparative Examples 1-3
Each compounding component shown in each of the following Tables 1 to 3 (all the compounding amounts in the table indicate “parts by weight”) is melt-kneaded with a biaxial kneader, and the resulting kneaded product is used using an annular die The conductive endless belts of Examples and Comparative Examples having dimensions of an inner diameter of 220 mm, a thickness of 100 μm, and a width of 250 mm were manufactured by extrusion molding. Each belt obtained was evaluated according to the following procedure.

<Measurement of MFR>
MFR (melt flow rate) measurement defined by the JIS K 7210 test method was performed under the conditions of a load of 5 kg, a preheating time of 10, 20 minutes at the measurement temperatures shown in each table. The smaller the MFR value and the smaller the time change (increase rate), the better the melt stability.

<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 mmsec
Measuring method: inclination at 0.5 to 0.6% elongation (when described, tangent method described in JIS)
Measurement environment: Room temperature (23 ± 3 ° C, 55 ± 10% RH)

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

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

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

<Image shift>
The belts of the examples and comparative examples were mounted on a tandem type image forming apparatus using the transfer conveyance belt shown in FIG. 2, and the presence / absence of image misalignment during the transfer operation was evaluated. When there was no image shift, “◯” was indicated, when a slight shift was generated, “△” was set, and when a large shift was generated, “X” was set.
The above measurement results are shown in Tables 1 to 3 below.

＊１）ポリエステル系エラストマーＡ：ペルプレン Ｅ−４５０Ｂ、東洋紡（株）製
＊２）ポリエステル系エラストマーＢ：ペルプレン ＥＮ−１６０００、東洋紡（株）製
＊３）ポリエステル系エラストマーＣ：ペルプレン ＥＮ−５０００、東洋紡（株）製
＊４）ポリエステル系エラストマーＤ：ペルプレン ＥＮ−２０００、東洋紡（株）製
＊５）ポリエステル系エラストマーＥ：ペルプレン Ｓ−９００１、東洋紡（株）製
＊６）ポリエステル系エラストマーＦ：ペルプレン Ｐ−９０Ｂ、東洋紡（株）製
＊７）ポリエステル系エラストマーＧ：ハイトレル ４７６７、東レ・デュポン（株）製
＊８）カルボジイミド化合物Ａ：カルボジライトＨＭＶ８ＣＡ、日清紡績（株）製
＊９）カルボジイミド化合物Ｂ：カルボジライトＢペレット、日清紡績（株）製
＊１０）カーボンブラック：電化ブラック粒状、電気化学工業（株）製
＊１１）ＰＢＴ：トレコン１４０１ＣＨ２、（株）東レ製
＊１２）ＰＢＮ：ＴＱＢ−ＯＴ、帝人化成（株）製

* 1) Polyester Elastomer A: Perprene E-450B, Toyobo Co., Ltd. * 2) Polyester Elastomer B: Perprene EN-16000, Toyobo Co., Ltd. * 3) Polyester Elastomer C: Perprene EN-5000, Toyobo * 4) Polyester Elastomer D: Perprene EN-2000, Toyobo Co., Ltd. * 5) Polyester Elastomer E: Perprene S-9001, Toyobo Co., Ltd. * 6) Polyester Elastomer F: Perprene P -90B, manufactured by Toyobo Co., Ltd. * 7) Polyester elastomer G: Hytrel 4767, manufactured by Toray DuPont Co., Ltd. * 8) Carbodiimide compound A: Carbodilite HMV8CA, Nisshinbo Co., Ltd. * 9) Carbodiimide compound B: Carbodilite B pellet, Nissin * 10) Carbon black: electrified black granular, manufactured by Denki Kagaku Kogyo Co., Ltd. * 11) PBT: Toraycon 1401CH2, manufactured by Toray Industries, Inc. * 12) PBN: TQB-OT, manufactured by Teijin Chemicals Ltd.

※）溶融安定性が悪く、寸法精度が悪化し画像ずれ発生

*) Poor melting stability, dimensional accuracy deteriorates and image shift occurs

  From the results of Tables 1 to 3 above, each containing a thermoplastic polyester elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, each having a tensile modulus of 800 MPa or more. In the belts of the examples, it was confirmed that both durability and environmental characteristics can be achieved, and there is no occurrence of problems such as image displacement.

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

Explanation of symbols

1, 11, 52a to 52d Photosensitive drums 2 and 7 Charging roll 3 Developing roll 4 Developing blade 5 Toner supply roll 6 Cleaning blade 8 Static eliminating 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)

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
Conductivity characterized by comprising mainly at least one thermoplastic polyester elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and having a tensile modulus of 800 MPa or higher. Endless belt. 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
Conductivity characterized by comprising mainly at least one thermoplastic polyester elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and having a tensile modulus of 800 MPa or higher. Endless belt. 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,
Conductivity characterized by comprising mainly at least one thermoplastic polyester elastomer having a crystalline melting point of 210 ° C. or higher as a base resin, a carbodiimide compound, and a conductive agent, and having a tensile modulus of 800 MPa or higher. Endless belt.   The conductive endless belt according to any one of claims 1 to 3, comprising two or more types as the thermoplastic polyester elastomer.   The conductive endless belt according to any one of claims 1 to 4, wherein an amount of the carbodiimide compound added is in a range of 0.05 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer.   The conductive endless belt according to any one of claims 1 to 5, comprising a thermoplastic polyester-based resin as a base resin within a range of 5 to 49% by weight of the total base resin.   The conductive endless belt according to claim 6, wherein the thermoplastic polyester resin is a polybutylene terephthalate resin or a polybutylene naphthalate resin.   An image forming apparatus using the conductive endless belt according to claim 1.

Images