JP4474234B2 - Endless belt for electrophotography and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic endless belt such as a transfer conveyance belt and an intermediate transfer belt used in an electrophotographic image forming apparatus, and an image forming apparatus having the electrophotographic endless belt.

  In addition to rigid drum shapes, transfer endless belt shapes (such as transfer conveyance members, intermediate transfer members, and electrophotographic photoreceptors) used in electrophotographic image forming apparatuses such as copying machines and laser beam printers ( Electrophotographic endless belts) are used.

  In recent years, color (full color, etc.) electrophotographic image forming apparatuses have been put into practical use, and demands for a transfer conveyance belt, an intermediate transfer belt, and the like are increasing.

  As an image forming system using a transfer / conveying belt, each color toner in an image forming unit (having an electrophotographic photosensitive member, a primary charging unit, an exposure unit, a developing unit, a transfer unit, etc.) arranged in series. A method of forming a color image by forming an image and sequentially transferring the image onto a transfer material that is sequentially conveyed to each image forming unit by a transfer material conveyance belt is well known.

  In addition, as an image forming system using an intermediate transfer belt, primary charging, exposure, and development are sequentially performed one color at a time on one electrophotographic photosensitive member, and toner images of each color are sequentially primary transferred onto the intermediate transfer belt. In addition, a so-called four-process intermediate transfer method for forming a color image by collectively transferring this onto a transfer material, or an image forming unit for each color arranged in series (electrophotographic photosensitive member / primary charging means) (Contains exposure means, development means, transfer means, etc.) Each color toner image is formed, transferred to an intermediate transfer belt, and then secondarily transferred onto a transfer material to form an image. In-line intermediate transfer systems are well known.

  As an endless belt for electrophotography, an endless belt mainly composed of a thermoplastic resin has been proposed because it can be manufactured at low cost and a general-purpose molding apparatus can be used. For example, Patent Document 1 discloses a polycarbonate resin. A seamless belt for electrophotography using the above, and Patent Document 2 disclose an endless belt for electrophotography using polyalkylene terephthalate.

  In recent years, durability of a belt has been demanded as an electrophotographic image forming apparatus becomes highly functional and durable. For the purpose of reducing running costs and downsizing of the device, belt units that were often used as replacement parts in the past are now being used with the same durable life as the main unit. Durability has been demanded. However, in a belt using a thermoplastic resin, there is a problem of cracking and tearing due to such durable use.

  As a method for solving this problem, Patent Document 3 discloses an electrophotographic endless belt using a polyamide resin, a polyamide resin, and a thermoplastic elastomer. Polyamide resins are suitable as materials for electrophotographic endless belts because they are excellent in flexibility and chemical resistance and also in wear resistance and friction. Moreover, it is cheaper than fluororesins and super engineering plastics, and can greatly contribute to cost reduction of the main body.

  However, although the bending resistance such as cracks and cracks can be solved by the above method, there is a problem that dirt such as paper dust or residual toner adheres to and accumulates on the belt and may cause transfer failure. In general, in an electrophotographic apparatus using a transfer conveyance belt or an intermediate transfer belt, a toner image is formed on the belt, and the density detection or detection is performed by detecting the reflected light density or position obtained from the toner image. Position detection is performed. For this reason, if the surface state of the belt changes due to paper dust or residual toner fixing due to durable use, accurate density detection or position detection cannot be performed, which may cause image defects.

In addition, the above-described method alone tends to cause poor dispersion of the conductive agent, which may cause uneven resistance or deterioration due to energization.
JP-A-3-89357 JP-A-8-99374 JP 2001-350347 A

  As described above, an electrophotographic endless belt capable of satisfying all the requirements required for a belt-shaped transfer member has been desired as the image forming apparatus has higher functions and higher durability.

  Accordingly, the object of the present invention is to solve the above-mentioned problems, at a low cost, without causing any cracks in the belt, dirt such as paper dust or residual toner even during durable use, small resistance unevenness, and energization. It is an object to provide a high-quality electrophotographic endless belt excellent in durability (leakage resistance) and an image forming apparatus using the electrophotographic endless belt.

  As a result of intensive studies to achieve the above object, the present inventors have found that an electrophotographic endless belt contains a polyamide resin and carbon black, and further, a fluorine atom-containing surfactant is added in an amount of 0.1% to 100 parts by mass of the polyamide resin. By containing 1 to 10 parts by mass, the belt is not low-cost, and even during durable use, there is no cracking, paper dust (paper fiber / filler), residual toner, etc., and resistance unevenness is small. As a result, the present inventors have found that the current-carrying durability is excellent, leading to the present invention.

  As a factor of the effect on the stains obtained by making it within the scope of the present invention, the electrophotographic endless belt contains a fluorine atom-containing surfactant, so that wettability (hydrophilicity) to moisture near the surface of the belt is increased. This is thought to increase. This is different from the conventional direction to prevent contamination by making it hydrophobic, but the details are not clear, but it is because a very small amount of moisture in the atmosphere is adsorbed, the surface resistance is reduced, and electrostatic adhesion is reduced. it is conceivable that. Further, it is considered that there is an effect that dirt is hardly fixed by adsorbing water between the belt and paper dust or toner. This effect is particularly effective in preventing adhesion of inorganic fillers that are paper fillers.

  In addition, as a factor of the effect of improving resistance unevenness and energization durability, by containing a fluorine atom-containing surfactant, the fluorine atom-containing surfactant interacts with carbon black or polyamide resin, thereby This is thought to be due to an improvement in the dispersion of carbon black. Further, this effect is effective when a polyamide resin is used, which is considered to be because the polyamide resin has a moderate polarity.

  That is, according to one aspect of the present invention, it contains a polyamide resin and carbon black, and further contains 0.1 to 10 parts by mass of a fluorine atom-containing surfactant with respect to 100 parts by mass of the polyamide resin. An electrophotographic endless belt is provided.

  According to another embodiment of the present invention, there is provided an image forming apparatus having the electrophotographic endless belt.

  According to the present invention, low-cost, high-quality electrophotography that is free from cracks and stains even during durable use, has excellent durability and cleaning properties, and excellent current durability. An endless belt and an image forming apparatus using the electrophotographic endless belt can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

  In the present invention, it is essential that the electrophotographic endless belt contains 0.1 to 10 parts by mass of the fluorine atom-containing surfactant with respect to 100 parts by mass of the polyamide resin, and in particular, the fluorine atom-containing surfactant. It is more preferable to contain 0.5-7 mass parts. By making the content of the fluorine atom-containing surfactant within the above range, a sufficient effect of reducing the adhesion of paper dust is exhibited, and withstand voltage due to the occurrence of defects on the electrophotographic endless belt (when voltage is applied) Insulation breakdown property) and molding stability are not reduced.

  Moreover, in this invention, it is preferable to contain 1-15 mass parts of polyether ester amide, polyether ester, or polyether amide with respect to 100 mass parts of polyamide resins. By containing these resins in the above-mentioned range, it is possible to reduce the adhesion amount of dirt and uneven resistance, and the surface of the molded product is not roughened and the mechanical strength is not lowered. As a factor that exerts such an effect, the inclusion of polyether ester amide, polyether ester or polyether amide increases the wettability of the belt and makes it difficult to get dirt like the fluorine atom-containing surfactant. This is considered to be an effect. Further, it is considered that the polyether ester amide, the polyether ester and the polyether amide are highly compatible with the fluorine atom-containing surfactant, so that the dispersion of the carbon black is further improved. Among the above-mentioned resins, it is more preferable to use polyether ester amide because of the stain resistance of the belt and the compatibility with the fluorosurfactant and polyamide.

  In the present invention, as the fluorine atom-containing surfactant, any of nonionic, cationic, anionic and both cation and anion can be used. For example, potassium perfluorobutanesulfonate, lithium perfluorobutanesulfonate, Alkali metal salts of perfluoroalkylsulfonic acids such as potassium perfluorooctanesulfonate and lithium perfluorooctanesulfonate, potassium perfluorobutanecarboxylate, lithium perfluorobutanecarboxylate, potassium perfluorooctanecarboxylate, perfluorooctane Examples include alkali metal salts of perfluoroalkyl carboxylic acids such as lithium carboxylate, but the compatibility and dispersibility in polyamide resin can be remarkably improved. Alkali metal salts are preferred. Of these, alkali metal salts of perfluorobutane sulfonic acid are more preferable, and potassium perfluorobutane sulfonate is more preferable.

  As the polyamide used in the present invention, known polyamides can be used. For example, polyamide 12 (PA12), polyamide 11 (PA11), polyamide 10 (PA10), polyamide 9 (PA9), polyamide 8 (PA8) ), Polyamide 7 (PA7), polyamide 6 (PA6), polyamide 4 · 6 (PA4 · 6), polyamide 6 · 6 (PA6 · 6), polyamide 6 · 10 (PA6 · 10), polyamide 6 · 12 (PA6) -12), polyamide 6T (PA6T) and polyamide 9T (PA9T) can be mentioned, and one kind or two or more kinds selected from these can be used.

  In the present invention, the polyamide resin includes a polyamide copolymer, a polymer alloy thereof, a polymer blend, and the like.

  Among the above polyamides, it is preferable to use one or more polyamide resins selected from polyamide 6 · 10, polyamide 6 · 12, polyamide 11 and polyamide 12.

  The above four kinds of polyamide resins have a particularly low water absorption among the various polyamide resins, have excellent dimensional stability, and have little fluctuation in electric resistance value even with environmental changes. Further, the melting point is lower than that of other polyamide resins, and molding is possible at a relatively low temperature, the difference between the melting temperature and the decomposition temperature is large, the moldable temperature range is wide, and the molding stability is excellent. Also, less energy is consumed for heating.

  Normally, the polyamide resin tends to increase the elastic modulus as the amide bond (—CONH—) concentration increases, but also tends to increase the water absorption rate. Polyamides 6 and 10, polyamides 6 and 12, polyamide 11 and polyamide 12 have a long methylene chain, have a low melting point, are flexible, and have a low water absorption rate. On the other hand, the elastic modulus tends to decrease.

  In the present invention, the molecular weight of the polyamide resin is preferably in the range of 5,000 to 50,000 in terms of number average molecular weight.

  Polyamide 6 · 10, polyamide 6 · 12, polyamide 11 and polyamide 12 are generally easily available on the market. Examples include Amilan manufactured by Toray, Rilsan manufactured by Atofina, Grillamide made by Ems Showa Denko, Daiamide made by Daicel Degussa, UBE nylon made by Ube Industries, DuPont Zytel, and the like.

  Furthermore, in the present invention, among the polyamides described above, it is preferable to use one or two polyamide resins selected from polyamide 6 · 10 and polyamide 12 from the viewpoint of the stain resistance of the belt.

  Moreover, these polyamides have high compatibility, and by blending appropriate amounts of two or more kinds, it is possible to multiply the advantages of each polyamide resin.

  The carbon black used in the present invention includes conductive carbon such as ketjen black and acetylene black, carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, and color ink subjected to oxidation treatment. Carbon, pyrolytic carbon and the like, and one or more kinds selected from these can be used. However, other known carbon blacks can be used and are not limited to the above materials.

  In the present invention, the content of carbon black is preferably 5 to 25 parts by mass of carbon black with respect to 100 parts by mass of the polyamide resin, considering the reinforcing effect of carbon black and cracks and cracks. In the present invention, a thermoplastic resin other than the polyamide resin may be added.

  Examples of the thermoplastic resin used in the present invention include polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), and styrene-butadiene. Copolymer, polybutadiene, polyisobutylene, polyamide (PA), polyacetal (POM), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyarylate, polycarbonate (PC), polyphenylene ether (PPE), polysulfone, polyether Sulphone, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyvinyl fluoride, acrylic, alkyl acrylate ester copolymer, polyether Examples include ester copolymers, polyether amide copolymers, polyurethane copolymers, and the like. However, other known thermoplastic resins can be used and are not limited to the above materials.

  In the present invention, in addition to carbon black, other electronic conductive agents, ionic conductive agents and the like can be used together.

  Electroconductive conductive agents other than carbon black include graphite such as natural graphite and artificial graphite, metal powder such as copper, nickel, iron and aluminum, metal oxide powder such as titanium oxide, zinc oxide and tin oxide, and polyaniline. , Conductive polymers such as polypyrrole and polyacetylene can be used, and one or two or more kinds selected from these can be used. However, other known electronic conductive agents can be used and are not limited to the above materials.

In addition, the ion conductive conductive agent is lauryl trimethyl ammonium, stearyl trimethyl ammonium, octadodecyl trimethyl ammonium, dodecyl trimethyl ammonium, hexadecyl trimethyl ammonium, modified fatty acid / dimethylethylammonium salt perchlorate, chlorate, Cationic surfactants such as borofluoride, sulfate, ethosulphate, benzyl bromide, benzyl halides such as benzyl chloride, quaternary ammonium salts, aliphatic sulfonates, higher Anionic surfactants such as alcohol sulfate ester salts, higher alcohol ethylene oxide addition sulfate ester salts, higher alcohol phosphate ester salts, higher alcohol ethylene oxide addition phosphate ester salts, zwitterionic surfactants such as various betaines, Grade alcohol ethylene oxide, polyethylene glycol fatty acid esters, antistatic agents such as nonionic antistatic agents such as polyhydric alcohol fatty acid _{esters, LiCF 3 SO 3, NaClO 4} , LiClO 4, LiAsF 6, LiBF 4, NaSCN, KSCN, Li ^+, such as ^NaCl, Na +, ^{K +} periodic table group 1 metal salts such or _NH ^{4 +} electrolytes salts of, and ^Ca _{(ClO 4)} Ca 2+ ₂ etc., the period of ^{Ba 2+,} etc. Examples include those having a group having an active hydrogen that reacts with an isocyanate such as at least one hydroxyl group, carboxyl group, primary or secondary amine group, and the like. Furthermore, with them, complexes of polyhydric alcohols such as 1,4-butanediol, ethylene glycol, polyethylene glycol, propylene glycol, polyethylene glycol and derivatives thereof, or monools such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether The complex of these is mentioned, The 1 type chosen from these or 2 types or more can be used. However, other known ion conductive resistance control agents and the like can be used, and are not limited to the above materials.

  Moreover, arbitrary additives can also be added in the range which does not impair the effect of this invention. For example, processing aids (ethylene-glycidyl methacrylate copolymer) for improving molding stability, hydrolysis inhibitors (carbodiimide, etc.), antioxidants (copper halides, phenolic, phosphorus-based, sulfur-based and amines) System), light stabilizer (HALS), flame retardant (halogen, phosphorus, antimony, magnesium hydroxide, silicone resin, etc.), lubricant (fluorine resin, silicone oil, etc.), and reinforcing agent (glass fiber, carbon) Fiber, aramid fiber, etc.), and one kind or two or more kinds selected from these can be used. However, other known additives are not limited to the above materials.

  In the present invention, as a method for dispersing a material such as a fluorine atom-containing activator in a polyamide resin, a known kneading and dispersing method can be used. Is preferred.

  In the present invention, the configuration of the electrophotographic endless belt may be a single layer or a multilayer. However, the resin layer is preferably a surface layer.

  Electrophotographic endless belts can be manufactured by joining sheet films (with a seam) or by forming a film into a cylindrical shape (seamless), but the belts are resistant to dirt, bend, and transfer. In view of the above, it is preferable to form seamlessly.

  As such a seamless endless belt manufacturing method, a manufacturing method that has high manufacturing efficiency and can suppress the cost is preferable, and the cylindrical melt is discharged from the tip of the annular die by extrusion of an extruder to a required length. A method of manufacturing an endless belt by cutting and then performing a process using a mold for the purpose of adjusting surface smoothness and dimensions is preferable. Among these, inflation molding is more preferable.

  FIG. 4 illustrates an embodiment of an endless belt manufacturing method for an electrophotographic endless belt according to the present invention. However, it is not subject to any restrictions.

  FIG. 4 includes two extruders 100 and 101 for forming a two-layer belt, but at least one in the present invention is sufficient.

  Next, a method for producing a single-layer electrophotographic endless belt will be described. First, based on a desired formulation, a molding resin, a conductive agent, an additive, and the like are premixed in advance, and the molding raw material that has been kneaded and dispersed is charged into a hopper 102 provided in the extruder 100. In the extruder 100, the set temperature and the screw configuration of the extruder are selected so that the forming raw material has a melt viscosity that enables belt forming in a later process and the raw materials are uniformly dispersed. The forming raw material is melted and kneaded in the extruder 100 to become a melt and enters the annular die 103. The annular die 103 is provided with a gas introduction path 104. When air is blown into the annular die 103 from the gas introduction path 104, the melt that has passed through the annular die 103 expands and expands in the radial direction.

  The gas blown at this time can be selected from nitrogen, carbon dioxide, argon and the like in addition to air, but is not limited thereto.

  The expanded molded body is pulled upward while being cooled by the cooling ring 105, and a tubular film 105 is formed. By cutting this into a desired width, an endless belt can be obtained.

  Reference numeral 106 denotes a stabilizer, 107 denotes a pinch roller, and 108 denotes a cutting device.

  Although the above description was about a single-layer belt, in the case of two layers, an extruder 101 is further arranged as shown in FIG. 4, and the two-layer annular die 103 is simultaneously formed with the kneaded melt of the extruder 100. The two-layer belt can be obtained by feeding the kneaded melt of the extruder 101 and expanding and expanding the two layers simultaneously.

  Of course, three or more layers may be used, and an extruder may be prepared in accordance with the number of layers.

  Next, the cylindrical film is processed using a mold for the purpose of adjusting surface smoothness and dimensions.

  Specifically, there is a method of using a set of cylindrical shapes having different diameters made of materials having different thermal expansion coefficients. The thermal expansion coefficient of the small-diameter cylindrical mold (inner mold) is set to be larger than that of the large-diameter cylindrical mold (outer mold), and the inner mold is covered with a cylindrical film formed on the inner mold. It is inserted into the outer mold, and the cylindrical film is sandwiched between the inner mold and the outer mold. The gap between the molds is obtained by calculating the difference between the heating temperature and the coefficient of thermal expansion between the inner mold and the outer mold and the required pressure. The mold installed in the order of the inner mold, the cylindrical film, and the outer mold is heated to near the softening point temperature of the resin. By heating, the inner mold having a large coefficient of thermal expansion expands from the outer mold, and a uniform pressure is applied to the entire surface of the tubular film. At this time, the surface of the resin film that has reached the vicinity of the softening point is pressed against the smooth inner surface of the outer mold, and the smoothness of the resin film surface is improved. Then, smooth surface properties can be obtained by cooling and removing the film from the mold.

  At this time, the film can be easily removed from the mold by applying a release agent to the inner surface of the outer mold or the surface of the film. Further, by using a release agent, the release agent is impregnated on the film surface, and contamination such as paper dust and residual toner fixation can be prevented, that is, filming resistance can be improved.

  Further, the surface smoothness of the belt can be adjusted by adjusting the surface roughness of the inner surface of the outer mold.

  Thereafter, an endless belt for electrophotography is manufactured by attaching a reinforcing member, a meandering preventing member, and a position detecting member and performing precision cutting as necessary.

In the present invention, the volume resistivity of the electrophotographic endless belt is preferably 10 ⁶ Ω · cm to 10 ¹³ Ω · cm, and particularly preferably 10 ⁸ Ω · cm to 10 ¹³ Ω · cm. .

In the present invention, the surface resistivity of the electrophotographic endless belt is preferably 10 ⁶ Ω / □ to 10 ¹⁵ Ω / □, and particularly 10 ⁷ Ω / □ to 10 ¹⁴ Ω / □. Is preferred.

  In the present invention, the electrical resistance of the electrophotographic endless belt is defined and measured as follows.

<Resistance measuring device>
Resistance meter: Super high resistance meter R8340A (manufactured by Advantest)
Sample box; Sample box TR42 for ultra-high resistance measurement (manufactured by Advantest)
However, the main electrode has a diameter of 25 mm, the guard ring electrode has an inner diameter of 41 mm, and an outer diameter of 49 mm.

<Resistance measurement sample>
A resistance measurement sample is prepared according to ASTM-D257-78. As a specific method, an endless belt for electrophotography is cut into a circle having a diameter of 56 mm, one side is provided with an electrode by a Pt—Pd vapor deposition film, and the other side is formed by a Pt—Pd vapor deposition film with a diameter of 25 mm. A main electrode and a guard electrode having an inner diameter of 38 mm and an outer diameter of 50 mm are provided. The Pt—Pd vapor deposition film can be obtained by performing a vapor deposition operation for 2 minutes with mild sputtering E1030 (manufactured by Hitachi, Ltd.). The sample after the vapor deposition operation is used as a measurement sample.

<Resistance measurement conditions>
Measurement atmosphere: 23 ° C./55% RH. Note that the measurement sample is previously left in an atmosphere of 23 ° C./55% RH for 12 hours or more.

Measurement mode: Program mode 5 (discharge 10 seconds, charge and major 30 seconds)
Applied voltage: 100 (V)

  The thickness of the electrophotographic endless belt in the present invention is preferably 45 to 300 μm, and more preferably 70 to 180 μm.

  In the present invention, the film thickness of the electrophotographic endless belt is defined and measured as follows.

<Thickness measurement method>
The film thickness of the electrophotographic endless belt of the present invention is a value obtained by measuring and averaging over the entire circumference of 40 points at equal intervals in the circumferential direction with respect to the center of the belt in a dial gauge having a minimum value of 1 μm.

  Since the endless belt for electrophotography of the present invention is excellent in bending durability, stain resistance and resistance uniformity, it is preferable to use it as a transfer conveyance belt and an intermediate transfer belt.

  Next, FIG. 1 shows a schematic configuration of a full-color image forming apparatus using the electrophotographic endless belt of the present invention as a transfer conveyance belt. The image forming apparatus shown in FIG. 1 has four image forming units arranged in parallel as electrophotographic process means, and each image forming unit includes an electrophotographic photosensitive member 1, a primary charger 2, a developing device 4, and a cleaning device. The member 19 is configured to be included. The developing devices 4Y, 4M, 4C, and 4K contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  In each image forming unit, the electrophotographic photosensitive member 1 is rotationally driven in the direction of the arrow at a predetermined speed, and these are uniformly charged to a predetermined polarity and potential by the primary charger 2. Each of the electrophotographic photoreceptors 1 thus charged is subjected to exposure light 3 output from an exposure means (not shown) such as slit exposure, laser beam scanning exposure, and LED exposure, thereby obtaining a target color image. An electrostatic latent image corresponding to the color component image of each color is formed, and each electrostatic latent image is developed by each developing device 4Y, 4M, 4C, 4K to be yellow toner image, magenta toner image, cyan toner image, and black toner. Each is visualized as an image.

  Each color toner image formed and supported on the electrophotographic photosensitive member 1 is transferred to the image forming unit by transferring the transfer material P from the paper feed roller 13 through the transfer material guide 14 to the transfer conveyance belt 5 and moving therewith. The yellow toner image, the magenta toner image, the cyan toner image, and the black toner image are superimposed and transferred by the transfer bias applied from the transfer member (transfer roller) 6 when passing through the image, and the composite corresponding to the target color image A color toner image is formed. The transfer bias is applied from the bias power source 30 with a polarity opposite to that of the toner. When a negative toner is used, the applied voltage is in the range of +100 V to +2 kV, for example.

  The transfer material P that has received the transfer of each color toner image as described above is neutralized by the separation charger 11 and separated from the transfer conveyance belt 5, and is then conveyed to the fixing device 12 to heat and fix the color toner image. Received image is output.

  Further, density detection and position detection are performed by forming a toner patch image on the transfer conveyance belt 5.

  The toner on the transfer / conveying belt 5 is electrostatically transferred to the electrophotographic photosensitive member 1 by applying a bias having a polarity opposite to that in the nip portion and the vicinity thereof with the electrophotographic photosensitive member 1 to be transferred. The conveyor belt is cleaned.

  Next, FIG. 2 shows a schematic configuration of a four-process full-color image forming apparatus using the electrophotographic endless belt of the present invention as an intermediate transfer belt.

  In FIG. 2, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven at a predetermined peripheral speed (process speed) in the direction of an arrow.

  The electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity and potential by the primary charger 2 during the rotation process, and then output from exposure means (not shown) such as slit exposure, laser beam scanning exposure, and LED exposure. By receiving the exposure light (image exposure light) 3, an electrostatic latent image corresponding to the first color component image (for example, yellow color component image) of the target color image is formed.

  Next, the electrostatic latent image is developed with yellow toner Y as the first color by the first developing device (yellow color developing device 4Y). At this time, the developing units of the second to fourth developing units (magenta developing unit 4M, cyan developing unit 4C and black developing unit 4K) are turned off and act on the electrophotographic photosensitive member 1. The yellow toner image of the first color is not affected by the second to fourth developing units.

  The intermediate transfer belt 15 is rotationally driven in the arrow direction at substantially the same peripheral speed as that of the electrophotographic photosensitive member 1 (for example, 97 to 103% with respect to the peripheral speed of the electrophotographic photosensitive member 1).

  In the process in which the yellow toner image of the first color formed and supported on the electrophotographic photosensitive member 1 passes through the nip portion between the electrophotographic photosensitive member 1 and the intermediate transfer belt 15, a primary transfer member (primary transfer roller) 16. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer belt 15 by the electric field formed by the primary transfer bias applied to the intermediate transfer belt 15. The primary transfer bias is applied from the bias power source 32 with a polarity opposite to that of the toner. When a negative toner is used, the applied voltage is in the range of +100 V to +2 kV, for example. The surface of the electrophotographic photosensitive member 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 15 is cleaned by the cleaning member 19.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black toner image are sequentially superimposed and transferred onto the intermediate transfer belt 15, and the composite color corresponding to the target color image is obtained. A toner image is formed.

  Reference numeral 17 denotes a secondary transfer member (secondary transfer roller), which is supported in parallel with the secondary transfer counter roller 18 and arranged in a state in which it can be separated from the lower surface of the intermediate transfer belt 15. Reference numeral 10 denotes a tension roller.

  In the primary transfer process of the first to third color toner images from the electrophotographic photosensitive member 1 to the intermediate transfer belt 15, the secondary transfer member 17 can be separated from the intermediate transfer belt 15.

  The composite color toner image transferred onto the intermediate transfer belt 15 is brought into contact with the intermediate transfer belt 15 and the secondary transfer roller 17 through the transfer material guide 14 from the paper feed roller 13 in synchronization with the rotation of the intermediate transfer belt. Transfer (secondary transfer) is performed on the transfer material P fed to the nip at a predetermined timing by the secondary transfer bias applied from the secondary transfer member 17. The applied voltage of the secondary transfer bias is in the range of +100 V to +2 kV, for example.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 12, heated and fixed, and output as an image.

  After the image transfer to the transfer material P is completed, the cleaning charging member 20 is brought into contact with the intermediate transfer belt 15 and is not transferred to the transfer material P by applying a bias having a polarity opposite to that of the electrophotographic photoreceptor 1. In addition, a charge having a polarity opposite to that of the electrophotographic photoreceptor 1 is applied to the toner (transfer residual toner) remaining on the intermediate transfer belt 15. Reference numeral 34 denotes a bias power source. The transfer residual toner is electrostatically transferred to the electrophotographic photosensitive member 1 at and near the nip portion with the electrophotographic photosensitive member 1, thereby cleaning the intermediate transfer member.

  Further, FIG. 3 shows a schematic configuration of a quadruple photosensitive type full-color image forming apparatus using the electrophotographic endless belt of the present invention as an intermediate transfer belt.

  The image forming apparatus shown in FIG. 3 has four image forming units arranged in parallel as electrophotographic process means, and each image forming unit includes an electrophotographic photosensitive member 1, a primary charger 2, a developing device 4, and a cleaning device. The member 19 is configured to be included. The developing devices 4Y, 4M, 4C, and 4K contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  In each image forming unit, the electrophotographic photosensitive member 1 is rotationally driven in the direction of the arrow at a predetermined speed, and these are uniformly charged by the primary charger 2 to a predetermined polarity and potential. Each of the electrophotographic photoreceptors 1 thus charged is exposed to exposure light 3 output from an exposure means (not shown), so that an electrostatic latent image corresponding to each color component image of the target color image is formed. The formed electrostatic latent images are developed by the developing devices 4Y, 4M, 4C, and 4K, and are visualized as yellow toner images, magenta toner images, cyan toner images, and black toner images, respectively.

  The intermediate transfer belt 15 is rotationally driven in the direction of the arrow at substantially the same peripheral speed as the electrophotographic photosensitive member 1 (for example, 97 to 103% with respect to the peripheral speed of the electrophotographic photosensitive member 1).

  Each color toner image formed and supported on the electrophotographic photosensitive member 1 passes from the primary transfer member (primary transfer roller) 16 to the intermediate transfer belt in the process of passing through the nip portion between the electrophotographic photosensitive member 1 and the intermediate transfer belt 15. 15 is transferred onto the outer peripheral surface of the intermediate transfer belt 15 by the primary transfer bias (primary transfer), and a composite color toner image corresponding to the target color image is formed. The primary transfer bias is applied from the bias power source 32 with a polarity opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to +2 kV.

  Reference numeral 17 denotes a secondary transfer member (secondary transfer roller), which is supported in parallel with the secondary transfer counter roller 18 and arranged in a state in which it can be separated from the lower surface of the intermediate transfer belt 15.

  The composite color toner image transferred onto the intermediate transfer belt 15 is brought into contact with the intermediate transfer belt 15 and the secondary transfer roller 17 through the transfer material guide 14 from the paper feed roller 13 in synchronization with the rotation of the intermediate transfer belt. Transfer (secondary transfer) is performed on the transfer material P fed to the nip at a predetermined timing by the secondary transfer bias applied from the secondary transfer member 17. The applied voltage of the secondary transfer bias is in the range of +100 V to +2 kV, for example.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 12, heated and fixed, and output as an image.

  The toner remaining on the intermediate transfer belt is removed by the belt cleaning member 21.

  The electrophotographic endless belt of the present invention can be suitably used for a transfer conveyance belt, an intermediate transfer belt, and the like as described above.

  As described above, the electrophotographic endless belt of the present invention has been described mainly focusing on the case where it is used as a transfer material conveyance belt or an intermediate transfer belt. In addition to the belt, the present invention can be applied to all endless belts used in electrophotographic apparatuses such as a photosensitive belt, a conveying belt other than a transfer conveying belt, a developing belt, a charging belt, and a paper feeding belt.

  The endless belt for electrophotography of the present invention may be mounted on the electrophotographic apparatus main body as it is, or may be used as an endless belt cartridge that can be attached to and detached from the main body of the electrophotographic apparatus. For example, a process cartridge in which the electrophotographic endless belt of the present invention and an electrophotographic process member such as an electrophotographic photosensitive member or a primary charging member are integrated may be used.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these.

Example 1
An electrophotographic endless belt was produced using the following materials.

Polyamide 12 100 parts by mass Potassium perfluorobutanesulfonate 0.5 parts by mass Polyetheresteramide 2 parts by mass Carbon black 15 parts by mass Olefin-based processing aid 1 part by mass Zinc oxide 20 parts by mass

  The raw materials were mixed with a tumbler and then kneaded with the following twin-screw extruder kneader, and the mixture was further made into a kneaded product having a particle diameter of 2 to 3 mm to obtain a molding raw material 1. The kneading apparatus and kneading conditions are as follows.

(Kneading equipment and kneading conditions)
・ Kneading device: 30mm diameter same direction rotating meshing twin screw extruder ・ Screw: Double type, L / D = 38
-Kneading temperature: 240 ° C
Extrusion conditions: Screw rotation 250 rpm, discharge rate 10 kg / h

  Next, the forming raw material 1 is put into the hopper 102 of the single-screw extruder 100 shown in FIG. 4, the set temperature is adjusted to 260 ° C. and extruded, and the tube-like film is perpendicular to the bus bar direction every 300 mm. The endless belt 1 was obtained by continuous cutting.

  The endless belt 1 was adjusted for size and surface smoothness using a pair of cylindrical shapes made of metals having different thermal expansion coefficients. An aluminum material having a high thermal expansion coefficient was used for the inner mold, and stainless steel having a lower thermal expansion coefficient than aluminum was used for the outer mold. The tubular film 1 was put on the inner mold having a high coefficient of thermal expansion, the inner mold was inserted into the outer mold, and heated at 220 ° C. for 20 minutes. After cooling, it was removed from the cylinder and the end was cut to obtain an electrophotographic endless belt 1 having a circumferential length of 500 mm, a width of 250 mm, and a thickness of 100 mm. The electrophotographic endless belt was provided with a meandering prevention member on the back surface.

  At this time, Flease 44 (manufactured by Neos) was used as a release agent on the film.

When the volume resistivity was measured according to the measurement conditions of the present invention, it was as follows:
Volume resistivity: 2.5 × 10 ¹⁰ Ω · cm

  Next, it was mounted on an electrophotographic apparatus (color laser printer) having the configuration shown in FIG. 1, and an output test of a full color image was performed in an environment of 23 ° C./55% RH. A good image free from misalignment, scattering, and voids could be obtained.

  Thereafter, a durability test of 50,000 output images was performed under the same environment. Observation of the electrophotographic endless belt after the durability test revealed no abnormalities such as pinhole leaks, cracks, and cracks. Also, the belt surface was good with little toner and paper stains. The evaluation results are shown in Table 3.

(Examples 2 to 12)
An electrophotographic endless belt was prepared and evaluated in the same manner as in Example 1 except that the materials used in Example 1 were changed as shown in Table 1. The evaluation results are shown in Table 3.

(Comparative Examples 1-4)
An electrophotographic endless belt was prepared and evaluated in the same manner as in Example 1 except that the materials used in Example 1 were changed as shown in Table 2. The evaluation results are shown in Table 4.

Tables 1 to 4 will be described below.
-Thermoplastic resin Polyamide 12: Ubesta 3030U manufactured by Ube Industries, Ltd.
Polyamide 6 · 10: Amilan CM2001 manufactured by Toray Industries, Inc.
Polyamide 6: Amilan CM1021XF manufactured by Toray Industries, Inc.
・ Fluorine-containing surfactant KFBS (potassium perfluorobutanesulfonate): F-top KFBS manufactured by Gemco
LFOS (lithium perfluorooctane sulfonate): F-top EF-105 manufactured by Gemco
PEEA: Sanyo Kasei Kogyo Pelestat NC6321
CB: Denka black powder product manufactured by Denki Kagaku Kogyo Co., Ltd. Zinc stearate: Sakai Chemical Co., Ltd. PTFE particles: Dynamer FX-5911X manufactured by Sumitomo 3M
Fluorine processing aid: Dinion TF9205 manufactured by Sumitomo 3M
・ Olefin processing aid: Bond First E manufactured by Sumitomo Chemical Co., Ltd.
・ Zinc oxide: One kind of zinc oxide manufactured by Sakai Chemical

-Volume resistivity It measured as mentioned above (100V application under N / N environment).

・ Applications ETB: Transfer conveyor belt ITB (1D): Four-process intermediate transfer belt ITB (4D): Four-photosensitive intermediate transfer belt

-Initial image Mounted on an electrophotographic apparatus (color laser printer) having the configuration shown in FIGS. 1 to 3, and conducted an output test of a full color image in an environment of 23 ° C./55%. The image was evaluated from the viewpoint of scattering, hollowing out. “A” indicates that a uniform image can be obtained, “B” indicates a slightly non-uniform but practically no problem level, and “C” indicates a clearly non-uniform level.

・ Pressure resistance When mounted on an electrophotographic apparatus (color laser printer) having the configuration shown in FIGS. 1 to 3 and outputting 50000 full-color images in an environment of 23 ° C./55%, pinhole leakage due to dielectric breakdown The presence or absence and the effect on the image were confirmed. "A" indicates that there is no pinhole leak and a uniform image is obtained, "B" indicates that there is pinhole leak but does not affect the image and is practically acceptable, and clearly affects the image Was “C”.

・ Stain resistance After mounting on an electrophotographic apparatus (color laser printer) having the configuration shown in FIGS. 1 to 3 and outputting a full-color image of 50000 sheets at 23 ° C./55%, paper dust and residual toner are fixed. The presence or absence of dirt, etc. and the effect on the image were confirmed. “A” indicates that there is no dirt such as paper dust or residual toner fixing, and “B” indicates that there is no problem on the image because there is no effect on the image. The product that came out was designated as “C”.

・ Bending resistance After mounting on an electrophotographic apparatus (color laser printer) having the structure shown in FIGS. 1 to 3 and outputting a full-color image of 50000 sheets in an environment of 23 ° C./55%, the belt may be cracked or stretched. The abnormality and its effect on the image were confirmed. "A" indicates that a uniform image can be obtained without cracks, elongation, etc. "B" indicates that there is no effect on the image although there are cracks, elongation, etc. "B", clearly affecting the image “C” was used.

1 is a diagram showing a schematic configuration of a full-color image forming apparatus using an electrophotographic endless belt of the present invention as a transfer conveyance belt. 1 is a diagram showing a schematic configuration of a four-process full-color image forming apparatus using an electrophotographic endless belt of the present invention as an intermediate transfer belt. FIG. 2 is a diagram showing a schematic configuration of a full-color image forming apparatus of a quadruple photosensitive system using the electrophotographic endless belt of the present invention as an intermediate transfer belt. It is a figure which shows schematic structure of the extrusion molding machine used for producing the endless belt for electrophotography of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Primary charger 3 Exposure light 4Y, 4M, 4C, 4K Developer 5 Transfer conveyance belt 6 Transfer member 7 Adsorption roller 8 Drive roller 9 Drive roller 10 Stretch roller 11 Separation charger 12 Fixing device 13 Supply Paper roller 14 Transfer material guide 15 Intermediate transfer belt 16 Primary transfer member 17 Secondary transfer member 18 Secondary transfer opposing roller 19 Cleaning member 20 Cleaning charging member 21 Belt cleaning member 30, 31, 32, 33, 34 Bias power source 100, DESCRIPTION OF SYMBOLS 101 Extruder 102 Hopper 103 Annular die 104 Gas introduction path 105 External cooling ring 106 Stabilizer plate 107 Pinch roller 108 Cutting device 110 Cylindrical film P Transfer material

Claims (11)

  An electrophotographic endless belt comprising a polyamide resin and carbon black, and further containing 0.1 to 10 parts by mass of a fluorine atom-containing surfactant with respect to 100 parts by mass of the polyamide resin.   The endless belt for electrophotography according to claim 1, wherein 0.5 to 7 parts by mass of a fluorine atom-containing surfactant is contained with respect to 100 parts by mass of the polyamide resin.   The endless belt for electrophotography according to claim 1 or 2, wherein the fluorine atom-containing surfactant is an alkali metal salt of perfluoroalkylsulfonic acid.   The electrophotographic endless belt according to claim 3, wherein the fluorine atom-containing surfactant is potassium perfluorobutanesulfonate.   The endless belt for electrophotography according to any one of claims 1 to 4, wherein the polyamide resin comprises one or more polyamide resins selected from polyamide 6 · 10, polyamide 6 · 12, polyamide 11 and polyamide 12.   The endless belt for electrophotography according to claim 5, wherein the polyamide resin comprises one or two kinds of polyamide resins selected from polyamide 6 · 10 and polyamide 12.   The electrophotographic endless belt according to any one of claims 1 to 6, further comprising 1 to 15 parts by mass of a polyether ester amide, a polyether ester, or a polyether amide with respect to 100 parts by mass of the polyamide resin.   The endless belt for electrophotography according to any one of claims 1 to 7, comprising 5 to 25 parts by mass of the carbon black with respect to 100 parts by mass of the polyamide resin.   The endless belt for electrophotography according to any one of claims 1 to 8, wherein the endless belt for electrophotography is a transfer conveyance belt.   The endless belt for electrophotography according to any one of claims 1 to 8, wherein the endless belt for electrophotography is an intermediate transfer belt.   An image forming apparatus comprising the endless belt for electrophotography according to claim 1.

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