JP2007025450A - Electrophotographic transfer member and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic transfer member and an image forming apparatus, giving high image quality free of image voids, and giving proper images, regardless of the environmental variations. <P>SOLUTION: The electrophotographic transfer member contains a low water-absorbing conductive resin (B), having a water absorption of ≤30% in an amount of 0.5-40 parts by mass with respect to 100 parts by mass of a thermoplastic resin (A), wherein the low water-absorbing conductive resin (B) preferably has a water absorption of ≤3%. The thermoplastic resin (A) comprises at least one selected from among a polyamide resin, a polyester resin and a fluorocarbon resin. The low water-absorbing conductive resin (B) is one or a mixture of two or more selected form among a polyether ester amide, a polyether amide and a polyolefin-ether copolymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic transfer member such as an intermediate transfer member, a transfer conveying member, and a paper conveying member used in an electrophotographic image forming apparatus such as an electrophotographic copying machine or a laser beam printer, and particularly reduces the influence of the environment. The present invention relates to an electrophotographic transfer member and an image forming apparatus.

  An electrophotographic image forming apparatus such as a copying machine or a laser beam printer uses an intermediate transfer member, a transfer conveyance member, a paper conveyance member, and the like. In recent years, color (full color, etc.) electrophotographic image forming apparatuses have been put into practical use, and the demand for transfer transfer members, intermediate transfer members, and the like is increasing.

  As a method of image formation using a transfer conveyance member, each color toner in an image forming unit for each color (including 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 sequentially transferring an image onto a transfer material such as paper that is sequentially conveyed onto an intermediate transfer member is well known.

  In addition, as an image forming method using an intermediate transfer member, 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 member. In addition, a so-called four-process intermediate transfer method for forming a color image by batch-transferring this onto a transfer material such as paper, or an image forming unit for each color arranged in series (electrophotographic photosensitive member, primary A charging unit, an exposure unit, a developing unit, a transfer unit, etc.), each color toner image is formed, transferred to an intermediate transfer member, and then secondarily transferred onto a transfer material to transfer the image. The in-line intermediate transfer method to be formed is well known.

  A transfer member having an adjusted electric resistance is generally used, and examples of the adjusting method include the following methods.

  1) A conductive filler such as carbon black is added to the thermoplastic resin.

  2) A surfactant is added to the thermoplastic resin.

  3) An ion conductive polymer (polymer type antistatic agent) is added to the thermoplastic resin.

The method 1) is an electric resistance adjustment method currently selected in many fields.
Although there is an advantage that it is not easily affected by temperature and humidity in the environment in which it is used, it is difficult to achieve uniform dispersion in the addition of conductive filler, and the transfer member produced by this method has an electrical resistance value. In some cases, defects such as transfer omissions and leaks may occur due to variations in the above. In addition, there is a problem that carbon black flows during use, the electric resistance value decreases, and the adsorption power decreases.

  In the method 2), the surface electrical resistance value can be lowered, but the volume resistance value is hardly lowered, and there is a drawback that the surfactant bleeds on the surface of the transfer member when the addition amount is increased. It was.

  The method 3) has few bleeding problems, but the electrical resistance does not decrease unless a certain amount of additive is added. Therefore, the environment changes depending on the hygroscopicity of the ion conductive polymer (polymer type antistatic agent). As a result, there is a problem that the electric resistance value varies.

  In Patent Document 1, there is a description of a medium transport belt in which a resin having a water absorption rate of 1% or less is selected for a thermoplastic resin, but there is no description regarding water absorption of a conductive resin having a resistance adjusting function, and there is no description regarding them. It is not considered.

Patent Document 2 discloses a member in which the water absorption of a resin composition containing a conductive filler having a pH of 5 or less, a hydrophobic inorganic filler, and a binder resin is 2% or less.
JP 2000-318865 A JP 2002-182487 A

  However, the above method alone has a problem that the resistance is not uniform, and there is a problem that deterioration due to energization occurs.

  In general, in an electrophotographic apparatus using a transfer conveying member or an intermediate transfer member, a toner image is formed on the member, and the density or position of the reflected light obtained from the toner image is detected. Searching. For this reason, if the surface state of the member changes due to paper dust or residual toner fixing due to durable use, accurate density detection and position search cannot be performed, causing a problem of image defects.

  Accordingly, the present inventors have proposed a new electrophotographic transfer member that solves the above-described problems and is different from the conventional one.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic transfer member and an image forming apparatus capable of obtaining high image quality without image omission and obtaining a good image even when the environment fluctuates.

  In order to achieve the above object, the present inventors include 0.5 to 40 parts by mass of a low water-absorbing conductive resin having a water absorption rate of 30% or less with respect to 100 parts by mass of the thermoplastic resin. The present inventors have found an electrophotographic transfer member that is low in cost, high in image quality, and capable of obtaining a good image even if the environment fluctuates during transportation or in a short time.

  As a factor of the effect of reducing the influence of the environment obtained by making it within the scope of the present invention, the low water-absorbing conductive resin contained in the electrophotographic transfer member has a water absorption of 30% or less. This is considered to be because the change in the electrical characteristics due to the environment of the electrical characteristics of the water-absorbing conductive resin is reduced, and the environmental fluctuation is suppressed. This is different from the direction of suppressing the water absorption of the entire conventional electrophotographic transfer member, and details are not clear, but by suppressing the environmental fluctuation of the water absorption of the direct material that affects the electrical characteristics of the transfer member, This is considered to be due to the effect of stabilizing the electrical characteristics of the transfer member.

  In particular, the factor that affects the image is the attracting force of the transfer material at high temperature and high humidity. When the attracting force is reduced, the transfer material is not stably conveyed, so that the transfer of toner is shifted and the image is transferred. By reducing the environmental fluctuation according to the present invention that causes a decrease, the adsorption force of the transfer material is stabilized, and high image quality can be provided.

  This effect is effective in any thermoplastic resin, but is particularly effective in the case of a thermoplastic resin composed of one or more of polyester resin, polyamide resin and fluororesin.

  The low water-absorbing conductive resin used in the present invention is effective as long as it has a water absorption of 30% or less. Particularly, any of polyether amide, polyether ester amide, and polyolefin-ether copolymer can be used. One or a mixture of two or more of these is effective.

  Of these, a copolymer of polymerized fatty acid polyamide and polyether ester amide is particularly effective.

  The electrophotographic transfer member in the present invention includes a roller, a drum, a seamless belt, and the like, and it is particularly effective to be a seamless belt.

  According to another embodiment of the present invention, an image forming apparatus having the electrophotographic seamless belt is proposed.

  According to the present invention, it is possible to obtain an electrophotographic transfer member with low cost, high image quality and little environmental fluctuation, and an image forming apparatus using the same.

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

  In the present invention, it is essential that the electrophotographic transfer member contains 0.5 to 40 parts by mass of a low water-absorbing conductive resin having a water absorption of 30% or less with respect to 100 parts by mass of the thermoplastic resin. If the water absorption rate of the conductive resin is greater than 30%, the electrical characteristics due to the environmental change of the electrophotographic transfer member in the present invention will change. If it is 40 parts by mass or more, the resistance value becomes too small, and the adsorptivity of a transfer material such as paper is lowered. If the amount is less than 0.5 parts by mass, the function of adjusting the electric resistance is not exhibited and the effect cannot be obtained.

  Furthermore, the water absorption rate of the low water-absorbing conductive resin is more preferably 3% or less.

  The low water-absorbing conductive resin used in the present invention is not particularly limited as long as it satisfies the characteristics of the present invention. However, polyether ester amide is used because of its durability and molding processability as an electrophotographic transfer member. , Polyetheramide, polyolefin ether copolymer, or a mixture of two or more thereof.

  The water absorption rate of the conductive resin is regulated by the value of one or a mixture of two or more, and the water absorption rate from the total amount of the conductive resin may be 30% or less.

  The water absorption rate in this invention is calculated | required by the A method defined by JIS-K-7209. More specifically, a sample in which a test piece was dried for 24 hours in a constant temperature layer maintained at 50 ° C. ± 2 ° C., placed in a desiccator and cooled to room temperature, was placed in a container containing distilled water at 23 ° C. ± 1 ° C. Put the test piece into. After immersion for 24 hours, the test piece is taken out of the water, the moisture on the surface of the test piece is wiped off with a dry cloth, taken out from the water, and weighed within one minute. The water absorption is obtained by the following formula.

Water absorption rate = [(mass of specimen after immersion−mass of specimen before immersion) / mass of specimen before immersion]
× 100 (%)
Hereinafter, the term “water absorption rate” means this measurement method and calculation method.

  As the thermoplastic resin used in the present invention, known thermoplastic resins can be used. For example, polyamide resins such as polyamide 11, polyamide 12, polyamide 6, polyamide 610, and polyamide 6-6, polyethylene, polypropylene, cyclohexane Polyolefin resins such as olefin polymers, ethylene-vinyl acetate copolymer resins, ethylene copolymers such as EEA, EMMA, EMAA, ionomer, polyester resins such as PET, PBT, PEN, and PET-G, PTFE, FEP, Fluorine resin such as PFA, PCTFE, ETFE, ECTFE, PVDF, styrene resin, acrylic resin such as PMMA, polycarbonate, polyacetal, PEEK, chlorinated polyethylene, soft polyvinyl chloride, hard polyvinyl chloride, polyarylate, Rephenylene ether, polyphenylene sulfide, ABS, AS, polybutadiene, polyurethane, urethane-based, styrene-based, olefin-based, vinyl chloride-based various elastomers, etc., including one or a mixture of two or more selected from these. Of the above thermoplastic resins, polyamide resins, polyester resins, and fluororesins are particularly suitable. Among these thermoplastic resins, these thermoplastic resins are particularly excellent in dimensional stability, and are excellent in stain resistance and moldability.

  Furthermore, rubbers such as olefin rubber, hydrogenated butadiene rubber, hydrogenated styrene-isoprene rubber, SBR, NBR, and fluoro rubber may be added as long as the characteristics of the present invention are not impaired.

  In the present invention, other electronic conductive agents and ion conductive agents can be used in combination as long as the characteristics are not impaired. For example, carbon black, natural graphite, artificial graphite, metal powders such as copper, nickel, iron and aluminum, metal oxides such as titanium oxide, zinc oxide and tin oxide, and conductive polymers such as polyaniline, polypyrrole and polyacetylene Among them, one or more of them can be used, and other known electronic conductive agents can be used, and are not limited to the above examples.

In addition, ionic conductive agents include lauryl trimethyl ammonium, stearyl methyl ammonium, octadodecyl trimethyl ammonium, dodecyl trimethyl ammonium, hexadecyl trimethyl ammonium, modified fatty acid / diethyl ethyl ammonium salt perchlorate, chlorate, borofluoride Cationic surfactants such as acid salts, sulfates, ethosulphate salts, benzyl bromide salts, benzyl halide salts such as benzyl chloride salts, quaternary ammonium salts, aliphatic sulfonates, higher alcohol sulfates Salts, anionic surfactants such as higher alcohol ethylene oxide addition sulfate ester salts, amphoteric surfactants such as various betaines, higher alcohol ethylene oxide, polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid esters Antistatic agents such as nonionic antistatic agents, _{etc., LiCF 3 SO 3, NaClO 4} , LiClO 4, LiAsF 6, LiBF 4, NaSCN, KSCN, Li + such ^{as NaCl,} Na +, periodic in ^{K +} etc. Table 1 group metal salts, electrolytes such as NH ₄ ⁺ salts, Ca ²⁺ , such as Ca (ClO ₄ ) ₂ , Periodic Table 2 group metal salts such as Ba ²⁺ , and antistatics thereof The agent has a group having an active hydrogen that reacts with an isocyanate such as at least one hydroxyl group, carboxyl group, or primary or secondary amine group.

  In addition, such complexes with 1,4-butanediol, ethylene glycol, polyethylene glycol, propylene glycol, polyethylene glycol and the like and polyhydric alcohols and derivatives thereof, or monools such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether And one or two or more kinds selected from these can be used. However, other known ion conductive resistance control agents 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, copper halides that prevent oxidative deterioration, antioxidants such as phenols, phosphoruss, sulfurs, and amines, processing aids that stabilize the molding process (ethylene-glycidyl methacrylate copolymer), hindered amines ( Weathering agents such as HALS), ultraviolet absorbers, halogen-based, phosphorus-based, antimony-based, flame retardants such as magnesium hydroxide and silicone resin, silicone oil, lubricants such as fatty acid saturated / unsaturated amide, glass fiber, carbon fiber, Various reinforcing agents such as aramid fibers, inorganic fillers, various colorants such as pigments, and the like can be used, but other known additives can also be used and are not limited to the above materials.

  In the present invention, as a method for dispersing the low water-absorbing conductive resin in the thermoplastic resin, kneading with a single-screw or twin-screw extruder, dry blending, kneading with a tandem extruder, kneading with a Banbury mixer, roll kneading, or the like is known. Although a dispersion method can be used, dispersion by a twin screw extruder is particularly preferable because of high dispersibility and productivity.

  The shape of the transfer member in the present invention may be a known shape such as a roll, a drum, or a belt. Among them, the belt is particularly preferred because the belt can be manufactured inexpensively and a general-purpose molding apparatus can be used. Is preferred.

  As a method for manufacturing the belt, there is a method in which sheet films are joined together (with seams), but in consideration of the stain resistance, bending resistance, and transferability of the belt, it is preferable to form the belt seamlessly.

  Such a seamless endless belt manufacturing method is preferably a manufacturing method that has high manufacturing efficiency and can reduce costs, and includes tube extrusion molding, centrifugal molding, injection molding, injection stretch blow, inflation extrusion molding, blow molding, and the like. However, it is a known manufacturing method and is not limited to the above.

  A method for producing an electrophotographic belt in the case where inflation extrusion molding or injection stretch blow molding is used will be described below. However, the present invention is not limited by them.

  FIG. 4 illustrates and describes the case where the inflation extrusion molding method is adopted as the method for producing the electrophotographic transfer member (belt) of the present invention.

  FIG. 4 includes two extruders 100 and 101 for inflation extrusion of a two-layer belt, but it is sufficient that at least one extruder is provided in the present invention.

  Next, the production of a single-layer electrophotographic belt will be described.

  First, based on a desired formulation, a thermoplastic resin for molding, a low water-absorbing conductive resin, and other additives are premixed in advance, and then the kneaded and dispersed molding material is put into a hopper 102 provided in the extruder 100. To do. In the extruder 100, the set temperature and the screw configuration of the extruder are selected so that the molding 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 expected introduction path 104, the melt that has passed through the annular die 103 expands and expands in the radial direction. At this time, the gas to be blown can be selected from nitrogen, carbon dioxide, argon and the like in addition to air, but is not limited thereto.

  Further, this gas can be adjusted to a desired temperature for molding.

  The expanded molded body is pulled upward while being cooled by the cooling ring 105, so that a cylindrical thermoplastic resin film 110 is formed. This is set to a desired width, and a belt is obtained by cutting with a length in the flow direction.

  Reference numeral 106 denotes a stabilizer for preventing the shake of the tubular film, 107 denotes a pinch roller, and 108 denotes a cutting device.

  Although the above description was about a single-layer thermoplastic belt, in the case of two layers, an extruder 101 is further arranged as shown in FIG. 4, and an annular die 103 for two layers is formed simultaneously with the kneaded body of the extruder 100. The kneaded melt of the extruder 101 is fed into the two layers, and two layers can be expanded and expanded simultaneously to obtain a two-layer belt.

  In the case of a multilayer belt, the belt is not limited to the two-layer structure described above, and may be three or more layers. In that case, any combination of an extruder and a die suitable for the layer may be used.

  Next, the cylindrical thermoplastic resin 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 molded tubular film. 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 determined by calculating the difference in the coefficient of thermal expansion between the inner mold and the outer mold at the heating temperature 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. The inner mold having a large coefficient of thermal expansion by heating 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 thermoplastic resin film that has reached the vicinity of the softening point is pressed against the inner surface of the outer mold that has been processed smoothly, and the smoothness of the 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 using a release agent on the inner surface of the outer mold or the surface of the film, or the outer surface of the inner mold or the inner surface of the film. When a release agent is used on the inner surface of the outer mold or the surface of the film, the release agent is impregnated into the film surface, preventing contamination such as paper dust and residual toner sticking, and improving filming resistance. it can.

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

  Thereafter, the reinforcing member, the meandering prevention member, and the position detection member are attached or cut as necessary to manufacture an electrophotographic belt.

  Next, a case where an electrophotographic belt is formed by an injection stretch blow molding method will be described.

  Based on a desired formulation, a thermoplastic resin for molding, a low water-absorbing conductive resin, and other additives were premixed in advance and then pelletized with a twin screw extruder. Moreover, this was shape | molded into the bottle-shaped preform with the injection molding machine. Weighing, compression, and injection were performed using an injection screw, and the mixture was injected into a molding die. After holding the pressure, the molded product was taken out and a preform was obtained after passing through a cooling step in the die. Thereafter, the obtained preform was uniformly heated at a predetermined temperature by a halogen heater, and then transferred to a stretch blow process.

  The preform is inserted into a mold having an internal volume larger than that of the preform and having a uniform cylindrical body portion at least equal to the width of the final shape of the electrophotographic belt, and stretch blow molding is performed along the mold interior. The molded preform was cooled and removed from the mold to obtain a desired bottle-shaped molded body. Thereafter, the bottle-shaped molded body was cut with an ultrasonic cutter according to a desired size to obtain a seamless intermediate transfer belt.

  The electrophotographic transfer member of the present invention is excellent in adaptability to changes in the environment in which the image forming apparatus is used, and thus is preferably used 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 transfer member 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. The developing unit 4 and the cleaning member 19 are 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 portion 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 transferred in a superimposed manner by a transfer bias applied from the transfer member (transfer roller) 6 when passing through the image, and are combined corresponding to the target color image. A color toner image is formed. The transfer bias is applied from the bias power supply 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 +200 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 transfer belt of the present invention as an intermediate 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 exposed from exposure means (not shown) such as slit exposure, laser beam scanning exposure, and LED exposure. By receiving the output exposure light (image exposure light) 3, an electrostatic image corresponding to a first color component image (for example, a 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 the electrophotographic photosensitive member 1 is not operated. 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 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 photoreceptor 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-corresponding roller 18 so as to 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 from the paper feed roller 13 through the transfer material guide 14 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, for example, in the range of +100 V to +2 kV.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 12 and is heat-fixed to output an image. After the image transfer to the transfer material P, 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 photosensitive member 1. Charges having a polarity opposite to that of the electrophotographic photoreceptor 1 are 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.

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

  The image forming apparatus shown in FIG. 3 has four image forming units juxtaposed 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 member. 19 is 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 the exposure light 3 output from the exposure means (not shown), whereby an electrostatic latent image corresponding to each color component image of the target color image. Each of the electrostatic latent images is developed by the developing units 4Y, 4M, 4C, and 4K, and is visualized as a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image.

  The intermediate transfer belt 15 is rotationally driven in the arrow direction 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 so as to be separated from the lower surface of the intermediate transfer belt 15.

  The composite color toner image transferred onto the intermediate belt 15 passes through the transfer material guide 14 from the paper feed roller 13 in synchronization with the rotation of the intermediate transfer belt, and a contact nip between the intermediate transfer belt 15 and the secondary transfer roller 17. The image is transferred (secondary transfer) to the transfer material P fed 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 member of the present invention can be suitably used for a transfer conveyance belt, an intermediate transfer belt, and the like as described above.

The electrophotographic transfer member of the present invention has been described mainly with respect to the case where it is mainly used as a transfer conveyance belt or an intermediate transfer belt. However, the electrophotographic transfer member of the present invention is not limited to a belt, but a roller or drum. In addition to transfer transfer members and intermediate transfer members, it is also used in electrophotographic apparatuses such as photosensitive members, transfer members other than transfer transfer members, developing members, charging members, and paper feed members. The electrophotographic transfer member of the present invention may be mounted on the electrophotographic apparatus main body as it is, or may be used as a cartridge that is detachable from the electrophotographic apparatus main body. For example, a process cartridge in which the electrophotographic transfer member 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.

In the present invention, the electrical low efficiency of the surface of the electrophotographic transfer member is preferably 10 ⁹ Ω / □ to 10 ¹⁴ Ω / □, and particularly 10 ¹⁰ Ω / □ to 10 ¹³ Ω / □. Is preferred.

In the present invention, the electrical resistance of the electrophotographic transfer member is defined and measured as follows.
<Resistance measuring device>
Resistance meter: Advantest R8340A
Sample box: TR42 manufactured by Advantest Corporation
The main electrode has a diameter of 25 mm, and 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-D-257-78. As a specific method, an electrophotographic transfer member 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 a main body having a diameter of 25 mm by a Pt—Pd vapor deposition film. An 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: N / N 23 ° C 55% RH
L / L 15 ° C 10% RH
H / H 32 ° C 85% RH
The measurement sample is left in the atmosphere under each condition for 12 hours or more.

Measurement mode: Program mode 5 (discharge 10 seconds, charge and major 30 seconds)
Applied voltage: 100 (V)
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 by inflation extrusion molding using the following materials.

  An electrophotographic transfer member was prepared using the following materials.

Polyamide Uvesta 3030U Ube Industries 100 parts by weight Polyetheresteramide TPAE-10 Fuji Kasei 5 parts by weight The above raw materials were mixed with a tumbler and then kneaded with the following twin-screw extruder kneader. A pelletized kneaded product having a particle size was obtained to obtain a forming raw material 1. The kneading apparatus and kneading conditions are as follows.
(Kneading equipment and kneading conditions)
・ Kneading device: 30mm diameter co-rotating 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 charged into the hopper 102 of the single-screw extruder 100 shown in FIG. 4 and is extruded by adjusting the set temperature to 260 ° C. The tube-like film is perpendicular to the flow direction every 300 mm. The belt 1 was obtained by continuous cutting.

  The size and surface smoothness of the belt 1 were adjusted using a pair of cylinders 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 belt 1 having a circumferential length of 500 mm, a width of 250 mm, and a thickness of 100 mm. The electrophotographic 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 surface resistivity was measured according to the measurement conditions of the present invention, it was as follows.

Surface resistivity: 6.5 × 10 ¹¹ Ω / □
Next, it is mounted on an electrophotographic apparatus (color laser printer) having the configuration shown in FIGS. 1 and 2, and L / L (15 ° C., 10% RH), N / N (23 ° C., 55% RH), H / H. Under each environment of (32 ° C., 85% RH), a full color image output test was performed and initial image evaluation was performed. As a result, it was possible to obtain a good image without image omission.

The evaluation results are shown in Table 1.
(Total water absorption of conductive resin)
The water absorption rate of each conductive resin added is determined by the method A defined in JIS-K-7209, and the ratio of the addition amount in the entire conductive resin is determined from the value. Calculated.

The criteria for image evaluation are as follows.
(leak)
○ No leaks at all △ Can be recognized very slightly on the image × Recognizable on the image ×× Remarkably recognized on the image (image omission)
○ Image omission is not observed at all △ Slightly seen in part on image × Recognizable on image XX Remarkably recognized on image (Examples 2 to 8)
An electrophotographic belt was produced 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 1.
(Comparative Examples 1-4)
An electrophotographic belt was produced 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 1.

1 is a schematic configuration diagram of a full-color image forming apparatus using an electrophotographic endless belt of the present invention as a transfer conveyance belt. 1 is a schematic configuration diagram of a four-process full-color image forming apparatus using an electrophotographic endless belt of the present invention as an intermediate transfer belt. 1 is a schematic configuration diagram of a quadruple photoreceptor type full-color image forming apparatus using an electrophotographic endless belt of the present invention as an intermediate transfer belt. FIG. It is a schematic block diagram of the extruder used for producing the electrophotographic endless belt 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 opposite direction 19 Cleaning member 20 Cleaning charging member 21 Belt cleaning member 30 to 34 Bias power source 100, 101 Extruder 102 Hopper DESCRIPTION OF SYMBOLS 103 Ring die 104 Gas introduction path 105 External cooling ring 106 Stabilizing plate 107 Pinch roller 108 Cutting machine 110 Cylindrical film P Transfer material

Claims (10)

  For electrophotography, comprising 0.5 to 40 parts by mass of low water-absorbing conductive resin (B) having a water absorption of 30% or less with respect to 100 parts by mass of thermoplastic resin (A) Transfer member.   2. The electrophotographic transfer member according to claim 1, wherein the low water-absorbing conductive resin (B) has a water absorption of 3% or less.   The electrophotographic transfer member according to claim 1 or 2, wherein the thermoplastic resin (A) comprises at least one selected from a polyamide resin, a polyester resin, and a fluororesin.   The low water-absorbing conductive resin (B) is any one of polyether ester amide, polyether amide, and polyolefin-ether copolymer, or a mixture of two or more thereof. An electrophotographic transfer member according to claim 1.   The low water-absorbing conductive resin (B) is a mixture of two or more types of conductive resins, and the water absorption rate of the conductive resin mixture is 30% or less. The electrophotographic transfer member as described.   The electrophotographic transfer member according to claim 1, wherein the low water-absorbing conductive resin (B) is a polyether ester amide and is a polymerized fatty acid-based polyamide.   The intermediate transfer member for further transferring the image formed on the second image carrier after the image formed on the first image carrier is transferred. The electrophotographic transfer member as described.   The transfer conveying member according to any one of claims 1 to 6, which is a transfer conveying member that contacts and is conveyed to a plurality of image carriers, and sequentially transfers images of different colors formed on the plurality of image carriers. The electrophotographic transfer member as described.   9. The electrophotographic transfer member according to claim 1, wherein the shape is a belt.   An image forming apparatus comprising the electrophotographic transfer member according to claim 1.

Images