JP2006139206A - Electroconductive endless belt and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive endless belt which exhibits stable performance for a long period of time without reduction in the durability even when the addition amount of carbon black is increased to a certain degree in response to the desired conductivity; and to provide an image forming apparatus using the same. <P>SOLUTION: The electroconductive endless belt of the tandem system for transfer and conveyance conveys a recording medium, held by electrostatic attraction, to four kinds of image forming bodies while being circularly driven by a driving member so as to sequentially transfer each toner image onto the recording medium. The electroconductive endless belt contains a base resin selected from the group comprising a thermoplastic resin, a polymer blend or a polymer alloy of two or more kinds of thermoplastic resins, and a polymer blend or a polymer alloy of one or more kinds of them and a thermoplastic elastomer, and carbon black, and is characterized in that the fracture face forming energy We, obtained by an EWF method, is 10-60 kJ/m<SP>2</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive endless belt (hereinafter also simply referred to as a “belt”) and an image forming apparatus using the same, and more particularly, to electrostatic recording in an electrophotographic apparatus such as a copying machine or a printer, an electrostatic recording apparatus, or the like. In the process, a conductive material used for transferring 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 onto a recording medium such as paper. The present invention relates to a conductive endless belt 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 a printing unit of a 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 by a driving roller (driving member) 30 and transferred to the intermediate transfer member 20 that rotates while rotating in contact with 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 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.

  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, and recently, many resin film belts with various improvements have been proposed because of their advantages such as low cost.

  In such a resin film belt, carbon black is usually added as a conductive agent to the base resin in order to develop conductivity. However, when the amount of carbon black added is increased in accordance with the desired conductivity, the elastic modulus increases, but on the other hand, brittleness appears and durability is lowered.

In order to solve such a problem, for example, Patent Document 1 discloses that a polyimide-based resin and carbon black are provided for the purpose of providing a semiconductive belt having improved tensile elastic modulus and durability while obtaining a desired surface resistivity. In a semiconducting belt containing a carbon black, a technique is described in which the maximum particle size of the secondary aggregation of carbon black and the standard deviation of the particle size distribution are prescribed values.
JP 2003-131463 A (claims, etc.)

  In recent years, the use conditions of belts have become more severe due to an increase in the temperature environment inside the equipment accompanying the increase in speed and compactness of image forming apparatuses. Therefore, there is an increasing demand for a belt having excellent durability capable of exhibiting stable performance even during long-term use under such severe use conditions.

  Therefore, an object of the present invention is to provide a stable performance over a long period of time without causing a decrease in durability even if the amount of carbon black added is increased to some extent depending on the desired conductivity in a resin film belt to which carbon black is added. It is an object of the present invention to provide a conductive endless belt that can be exhibited and an image forming apparatus using the same.

  As a result of intensive studies, the present inventors used the fracture toughness (toughness) of the material as an index of belt durability, and used the EWF (Essential Work of Fracture) method as the evaluation method, and obtained physical property values by this. The inventors have found that the above problems can be solved by defining the belt with a certain fracture surface formation energy, and have completed the present invention.

  Various parameters are known as parameters for evaluating the fracture toughness of materials. However, conventionally used test methods such as a JIS right-angle tear test and a bending resistance test cannot sufficiently evaluate belt durability. That is, since the thick material breaks brittlely (linear), it is possible to evaluate the fracture toughness by the stress intensity factor Kc, while the thin material such as a belt breaks with plastic deformation (nonlinear). Therefore, the measurement of the fracture toughness requires an evaluation based on the elastoplastic fracture toughness value (J integral), and a complicated operation procedure is required. Therefore, in any case, the conventional test method is insufficient for the evaluation of the belt material.

  The EWF method is a simple method for evaluating the nonlinear fracture toughness of a thin-walled material accompanying such plastic deformation, and the fracture energy Wf is determined based on the energy Wp consumed for plastic deformation and the energy for forming a fracture surface. It is divided into We and evaluated. In the present invention, by defining the belt using physical property values related to the fracture toughness of the belt material obtained by the EWF method, a belt added with carbon black has realized excellent durability that could not be achieved conventionally. It is.

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 is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. containing a base resin, and carbon black, and the fracture surface formation energy We obtained by EWF method is characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less.

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 is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. containing a base resin, and carbon black, and the fracture surface formation energy We obtained by EWF method is characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less.

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 is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. containing a base resin, and carbon black, and the fracture surface formation energy We obtained by EWF method is characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less.

  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, it is possible to prevent a decrease in durability even when the amount of carbon black used as the conductive agent is increased to some extent by adopting the above configuration. As a result, it is possible to realize a conductive endless belt having desired conductivity and capable of exhibiting stable performance over a long period of time. Therefore, according to the image forming apparatus of the present invention using such a conductive endless belt, it is possible to stably obtain a high-quality image even during long-term use.

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 holder) 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 comprises a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or thermoplastic elastomer of any one or two of these and a thermoplastic elastomer. It is characterized in that it contains a base resin selected from the group consisting of polymer alloys and carbon black, and the fracture surface formation energy We determined by the EWF method is within a predetermined range.

As described above, the EWF method is a kind of material toughness evaluation method, and can evaluate the fracture toughness of thin materials such as thin plates, sheets, and films accompanied by plastic deformation. The fracture surface formation energy We in the EWF method is expressed by the following equation using the plastic deformation energy Wp consumed for plastic deformation and the fracture surface formation energy We for forming the fracture surface:
Wf = Wp · L + We
(Wf: total fracture energy, Wp: plastic deformation energy, We: fracture surface formation energy, L: ligament length). In the present invention, the fracture toughness of the belt is defined using the fracture surface formation energy We in the above formula.

Specifically, a strip-shaped sample 100 as shown in FIG. 5 is produced, and the distance L between the notches 101 formed with a razor is defined as the ligament length, and measurement can be performed as follows.
<Measurement method>
(1) Samples with different ligament lengths L are produced.
(2) determining the total fracture surface formation energy W _F from the load displacement curve (W _F: area of load-displacement curve).
(3) Wf (Wf = W _F / L × t, t: film thickness) is plotted against L, and Wp and We are obtained from the slope and intercept according to the above formula.

In the present invention, the fracture surface formation energy We of the belt as defined above is required to be 10 kJ / m ² or more 60 kJ / m ² or less. When the fracture surface formation energy We is less than 10 kJ / m ² , durability is insufficient, and cracks may occur during use. Although fracture formation energy is good durability if 10 kJ / m ² or more, when it exceeds 60 kJ / m ^2, of at the time of manufacture, such as cutting or the end face treatment of the belt from the extruded tube by the cutter 2 It becomes extremely difficult to perform the next processing.

  In the present invention, it is only important that the value of the fracture surface formation energy We is within the above range, and other specific belt materials and configurations are not particularly limited. As the base resin, among the thermoplastic resins described above, polyalkylene terephthalate resins such as polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polyalkylene naphthalate resins such as polyethylene naphthalate resin ( PEN), polybutylene naphthalate resin (PBN), polymer blend or polymer alloy of polyalkylene terephthalate resin and polyalkylene naphthalate resin, polymer blend of polyalkylene terephthalate resin and polycyclohexylene dimethylene terephthalate resin (PCT) or Polymer alloy, polymer blend or polymer alloy of polyalkylene naphthalate resin and polycyclohexylene dimethylene terephthalate resin (PCT), Preferable examples include rephenylene sulfide resin (PPS), polyamide resin (PA), polyacetal resin (POM), liquid crystal polymer, acrylonitrile-butadiene-styrene resin (ABS), fluororesin, polycarbonate resin (PC), PCT, and the like. it can. Examples of the thermoplastic elastomer that can be suitably used with one or more of these include polyester elastomers, olefin elastomers, and styrene elastomers.

A preferable fracture surface formation energy We value when using each base resin is, for example, 10 kJ when the base resin is mainly composed of a polymer blend or polymer alloy of a polyalkylene terephthalate resin and a polyalkylene naphthalate resin. / m ² or more 60 kJ / m ² or less, when based on a polymer blend or polymer alloy of polyalkylene terephthalate resin and PCT is 10 kJ / m ² or more 60 kJ / m ² or less, the polyalkylene naphthalate resin and the PCT If the main component polymer blends or polymer alloys 10 kJ / m ² or more 60 kJ / m ² or less, if the main component of PPS is 10 kJ / m ² or more 40 kJ / m ² or less, and composed mainly of a polyalkylene terephthalate resin If it is 10 kJ / m ² or more 50 kJ / m ² or less, Real if the main component is sharp emission naphthalate resin 10 kJ / m ² or more 50 kJ / m ² or less, or less 60kJ / m ² 10kJ / m ² or more if a main component PA, if the main component POM resin It is 10 kJ / m ² or more 40 kJ / m ² or less, if the main component of the liquid crystal polymer is 10 kJ / m ² or more 40 kJ / m ² or less, if the main component ABS is 10 kJ / m ² or more 40 kJ / m ² or less , when the fluororesin as a main component 10kJ / m ² or more 40 kJ / m ² or less, if the main component PC resin 10kJ / m ² or more 50 kJ / m ² or less, if the main component PCT is 10kJ / M ² or more and 50 kJ / m ² or less.

In the present invention, it is necessary to use carbon black as a conductive agent added to the base resin. Such carbon black is not particularly limited, and 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 It can be appropriately selected from general-purpose materials such as applied color ink carbon, pyrolytic carbon, natural graphite, and artificial graphite. The amount of addition depends on the type of base resin used, but in order to obtain fracture surface formation energy We of 10 kJ / m ² or more, the amount is 20 parts by weight or less with respect to 100 parts by weight of the base resin. More preferably, it is about 3 to 15 parts by weight.

Further, a conductive agent other than carbon black may be used in combination. Examples of the other conductive agent include lauryl trimethyl ammonium, stearyl trimethyl ammonium, octadecyl trimethyl ammonium, dodecyl trimethyl ammonium, hexadecyl trimethyl ammonium, modified fatty acid and dimethyl. Cations such as quaternary ammonium such as ethylammonium perchlorate, chlorate, borofluoride, sulfate, ethosulphate salt, benzyl halide salt (verzyl bromide salt, benzyl chloride salt, etc.) Surfactant; Anionic surfactant such as aliphatic sulfonic acid, higher alcohol sulfate, higher alcohol ethylene oxide addition sulfate, higher alcohol phosphate; amphoteric surfactant such as various betaines; higher alcohol Ji alkylene oxide, polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid antistatic agent such as a nonionic antistatic agents such as _{esters, LiCF 2 SO 2, NaClO 4} , LiBF 4, periodic table Group 1 metal salts such as NaCl A metal salt of Group 2 of the periodic table such as Ca (ClO ₄ ) ₂ : and a group having an active hydrogen with which these antistatic agents react with isocyanate (hydrogen group, carboxyl group, primary or secondary amine group, etc.) And those having one or more. 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. Examples thereof include conductive agents; metals and metal oxides such as tin oxide, titanium oxide, zinc oxide, nickel, and copper; conductive polymers such as polyaniline, polypyrrole, and polyacetylene.

  The addition amount of these other conductive agents is preferably about 0.1 to 100 parts by weight, more preferably about 1 to 80 parts by weight with respect to 100 parts by weight of the base material.

In the present invention, the volume specific resistance value of the belt is adjusted to about 10 ⁷ to 10 ¹⁴ Ω · cm, particularly about 10 ⁸ to 10 ¹³ Ω · cm by appropriately blending a conductive agent such as carbon black. be able to. The surface resistance value of the belt is preferably adjusted to about 10 ⁰ to 10 ¹³ Ω / cm ² .

In addition to the above-described components, other functional components can be appropriately added to the belt of the present invention as long as the effects of the present invention are not impaired. For example, the aspect ratio is 10 as a reinforcing material. It is preferable to improve the mechanical properties (strength, elastic modulus, impact strength, etc.) by adding the above inorganic compounds. Examples of such inorganic compounds include calcium silicate hydrate whisker (Ca ₆ · Si ₆ O ₁₇ · (OH) ₂ ), basic magnesium hydroxide hydrate whisker (MgSO ₄ · 5Mg (OH) ₂ · 3H). ₂ O), potassium titanate whiskers (K ₂ O · 6TiO ₂ and K ₂ O · 8TiO ₂ ), aluminum borate whiskers, potassium titanate whiskers, carbon whiskers, graphite whiskers, titanium carbide whiskers, conductive potassium titanate whiskers Conductive barium titanate whisker, conductive titanium oxide whisker, wollastonite whisker, sepiolite whisker, aluminum borate whisker, alumina whisker, chromium whisker, copper whisker, iron whisker, nickel whisker, silicon carbide whisker, silicon nitride whisker, Zinc oxide whisker and carbonated mosquito Etc. can be cited Shiumuuisuka, among others calcium silicate hydrate whisker, basic magnesium water hydrate whiskers and potassium titanate whiskers are preferred, calcium silicate hydrate whiskers is more preferable. The amount of the inorganic compound added can be about 1 to 20 parts by weight with respect to 100 parts by weight of the base resin. In addition, various fillers, coupling agents, antioxidants, lubricants, surface treatment agents, pigments, UV absorbers, antistatic agents, dispersants, neutralizers, foaming agents, crosslinking agents, molding modifiers, etc. Alternatively, a coloring agent may be added to color the belt.

  The belt of the present invention has a laminated structure in which two or more layers are laminated, even if it has a single-layer structure consisting of a single layer, as long as it satisfies the above-described conditions relating to the fracture surface formation energy We. There is no particular limitation. In the case of a laminated structure, two or more layers having different compositions may be laminated, or two or more layers having the same composition may be included.

  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.

  Further, the conductive endless belt of the present invention has a surface on the side in contact with a driving member such as the driving roller 9 or the driving roller 30 of FIG. 3 in the image forming apparatus of FIG. 2, as shown by a one-dot chain line in FIG. A fitting portion that fits with a fitting portion (not shown) formed on the drive member may be formed, and the conductive endless belt of the present invention is provided with such a fitting portion and drives this. Shifting in the width direction of the conductive endless belt can be prevented by running with a fitting portion (not shown) provided on the member.

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

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

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

  Further, the method for producing the conductive endless belt of the present invention is not particularly limited, and can be obtained, for example, by kneading a resin material as a main component and a functional component such as a conductive material by a biaxial kneader. The kneaded product can be produced by extrusion molding using an annular die. 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 specifically by way of examples.
(Example 1)
70 parts by weight of PBN resin (manufactured by Teijin Chemicals Ltd., trade name: TQB-OT), 30 parts by weight of PET (manufactured by Unitika Ltd., trade name: SA1206), and electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) 15 A conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm and a width of 250 mm was obtained by melt-kneading the parts by weight with a biaxial kneader and extruding the obtained kneaded product. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 2)
70 parts by weight of PCT resin (manufactured by Eastman Chemical Co., Ltd., trade name THERMX6761), 30 parts by weight of PET (trade name: SA1206, manufactured by Unitika Ltd.), 15 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) Was melt-kneaded with a biaxial kneader, and the resulting kneaded product was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 3)
100 parts by weight of PPS resin (manufactured by Dainippon Ink Co., Ltd., trade name LD-10) and 5 parts by weight of Ketjen Black (trade name of EC600JD by Lion Corporation) are melt-kneaded in a biaxial kneader. Then, the obtained kneaded product was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Comparative Example 1)
100 parts by weight of COP resin (manufactured by Nippon Zeon Co., Ltd., trade name 1410R) and 20 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) are melt-kneaded with a twin-screw kneader, and the obtained kneading The product was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 4)
100 parts by weight of PA12 (manufactured by Ube Industries, Ltd., trade name: 3035U) and 10 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo) are melt-kneaded with a twin-screw kneader, and the resulting kneaded product Was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 5)
100 parts by weight of a PCT resin (manufactured by Eastman Chemical Co., Ltd., trade name THERMX6761) and 10 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) are melt-kneaded with a twin-screw kneader, and the resulting kneaded product Was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 6)
70 parts by weight of polyphenylene oxide (PPO) resin (manufactured by GE Plastics, Inc., trade name EBN9003) and 13 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were melt-kneaded in a biaxial kneader. The obtained kneaded product was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Example 7)
100 parts by weight of PEN resin (manufactured by Teijin Kasei Co., Ltd., trade name: Teonex N8065) and 15 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were melt-kneaded with a twin-screw kneader, and obtained. By extruding the kneaded product, a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm was obtained. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

(Comparative Example 2)
100 parts by weight of PPS resin (manufactured by Dainippon Ink Co., Ltd., trade name LD-10) and 20 parts by weight of electrified black (manufactured by Denki Kagaku Kogyo Co., Ltd.) are melt-kneaded in a twin-screw kneader to obtain The kneaded product thus obtained was extruded to obtain a conductive endless belt having an inner diameter of 245 mm, a thickness of 0.1 mm, and a width of 250 mm. Ten strips of 120 × 50 mm are cut out from the obtained belt so that 120 mm is in the circumferential direction, test pieces with different notch lengths are produced, and the fracture surface formation energy We is determined according to the EWF test method described above. It was measured.

Further, the belts of the above examples and comparative examples were mounted on a tandem type image forming apparatus using the transfer conveyance belt shown in FIG. 2, and the endurance test of 100,000 sheets of A4 paper was performed by repeating the transfer operation. The results were evaluated as whether or not the rotation durability caused cracks on the surface and end portions due to the rotation and the belt was torn, resulting in breakage and adverse effects on image characteristics.
These results are shown in FIG. 6 and Tables 1 and 2 below.

As shown in Tables 1 and ² above, the belts of the examples in which the fracture surface formation energy We was 10 kJ / m ² or more showed good durability, but the fracture surface formation energy We was less than 10 kJ / m ^2. In the belt of the comparative example, cracks occurred in the belt during the durability test. From this result and FIG. 6, it was found that the amount of carbon black added must be 20 parts by weight or less in order to obtain a fracture surface formation energy We of 10 kJ / m ² or more.

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. 5 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. It is the schematic of the sample used for an EWF test method. It is a graph which shows the relationship between the addition amount of carbon black, and the fracture surface formation energy We.

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 samples 101 notches

Claims (20)

Conductive endless belt for tandem transfer and conveyance, in which a recording medium held by electrostatic adsorption is circulated and driven by a driving member, conveyed to four types of image forming bodies, and each toner image is sequentially transferred to the recording medium. In
It is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. a base resin, containing carbon black, and the fracture surface formation energy We obtained by EWF method, conductive endless belt, characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less. The toner image formed between the image forming body and the recording medium is circulated and driven by a driving member, and the toner image formed on the surface of the image forming body is once transferred and held on the surface of the image forming body and transferred to the recording medium. In the conductive endless belt for the intermediate transfer member
It is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. a base resin, containing carbon black, and the fracture surface formation energy We obtained by EWF method, conductive endless belt, characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less. Arranged between the four types of image forming bodies and the recording medium, and circulated and driven by a driving member, and sequentially transferring and holding the toner images formed on the surfaces of the four types of image forming bodies on the surface of the recording medium. In a conductive endless belt for a tandem intermediate transfer member that transfers this to a recording medium,
It is selected from the group consisting of a thermoplastic resin, a polymer blend or polymer alloy of two or more thermoplastic resins, and a polymer blend or polymer alloy of any one or two of these and a thermoplastic elastomer. a base resin, containing carbon black, and the fracture surface formation energy We obtained by EWF method, conductive endless belt, characterized in that it is 10 kJ / m ² or more 60 kJ / m ² or less. Claim wherein the base resin is a main component a polymer blend or polymer alloy of polyalkylene terephthalate resin and a polyalkylene naphthalate resin and the fracture surface formation energy We is 10 kJ / m ² or more 60 kJ / m ² or less The conductive endless belt according to any one of 1 to 3. The base resin is composed mainly of a polymer blend or polymer alloy of xylene terephthalate resin to polyalkylene terephthalate resin and polycyclo, and the fracture surface formation energy We is at 10 kJ / m ² or more 60 kJ / m ² or less The electroconductive endless belt as described in any one of Claims 1-3. The base resin is composed mainly of a polymer blend or polymer alloy of xylene terephthalate resin to polyalkylene naphthalate resin and polycyclo, and the fracture surface formation energy We is 10 kJ / m ² or more 60 kJ / m ² or less The conductive endless belt according to any one of claims 1 to 3. The base resin is composed mainly of a polyphenylene sulfide resin, and electroconductive endless as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 40 kJ / m ² or less belt. The base resin is composed mainly of a polyalkylene terephthalate resin, and the fracture surface formation energy We is conductive as claimed in any one of 10 kJ / m ² or more 50 kJ / m ² or less is claims 1-3 Endless belt. The base resin is composed mainly of a polyalkylene naphthalate resin, and conductive as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 50 kJ / m ² or less Sex endless belt. The base resin is composed mainly of a polyamide resin, and conductive endless belt as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 60 kJ / m ² or less . The base resin is mainly composed of polyacetal resin, and conductive endless belt as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 40 kJ / m ² or less . The base resin is mainly composed of liquid crystal polymer, and conductive endless belt as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 40 kJ / m ² or less . The base resin is an acrylonitrile - butadiene - styrene resin as a main component, and the fracture surface formation energy We is as claimed in any one of claims 1 to 3 is 10 kJ / m ² or more 40 kJ / m ² or less Conductive endless belt. The base resin is composed mainly of fluorocarbon resin and electroconductive endless belt as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 40 kJ / m ² or less . The base resin is mainly composed of polycarbonate resin, and conductive endless belt as claimed in any one of claims 1-3 wherein the fracture surface formation energy We is 10 kJ / m ² or more 50 kJ / m ² or less . The base resin is composed mainly of poly-cyclohexylene dimethylene terephthalate resin, and the fracture surface formation energy We is any one claim of 10 kJ / m ² or more 50 kJ / m ² or less is claims 1-3 Conductive endless belt.   The conductive endless belt according to any one of claims 1 to 16, wherein the thermoplastic elastomer is a polyester elastomer, an olefin elastomer, or a styrene elastomer. The conductive endless belt according to any one of claims 1 to 17, wherein a surface resistance value is in a range of 10 ⁰ to 10 ¹³ Ω / cm ² .   The conductive endless belt according to any one of claims 1 to 18, wherein an inorganic compound having an aspect ratio of 10 or more is added as a reinforcing material.   An image forming apparatus using the conductive endless belt according to claim 1.

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