JP2006284759A - Method for manufacturing coated tube for charging member, charging member, cartridge for electrophotographing device, and electrophotographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a coated tube for a charging member which suppresses resistance unevenness by lowering the generation level of weld. <P>SOLUTION: The method includes a step of extruding a tube in the gravitational direction, an air cooling step, a water cooling sizing step, a tube take-off step, and a tube cutting step, and in which the charging member is formed by sheathing an elastic body layer on the outer periphery of a cored bar with a multi-layered seamless tube. The method is characterized in that the extruding step is a step of mixing and extruding resin by using a metal mold such that at least one of an exit portion of the metal mold on a surface coming into contact with the coated tube on a side of an internal surface of the coated tube and an exit portion of the metal mold on a surface coming into contact with the coated tube on a side of an external surface rotates. The charging member obtained by the manufacturing method, a cartridge for an electrophotographing device mounted with the charging member, and the electrophotographing device are also included. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a charging member that is placed in contact with a member to be charged and charges the member to be charged when a voltage is applied thereto, and a method for manufacturing the coated tube thereof. The present invention also relates to an electrophotographic cartridge having the charging member and an electrophotographic apparatus.

  In recent years, a contact charging type charging unit has been adopted as a charging unit used in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus. Contact charging is to charge a charged body to a predetermined polarity and potential by applying a voltage to a charging member placed in contact with the charged body, and the voltage of a power source can be lowered, such as ozone. There are advantages that the generation of corona products can be reduced, the structure is simple, and the cost can be reduced.

  The voltage applied to the charging member has a peak-to-peak voltage that is at least twice the charging start voltage of the object to be charged when a DC voltage is applied to the contact charging member, in addition to a method in which only DC is applied (DC application method). There is a technique (AC application method) in which an oscillating electric field (electric field whose voltage value changes periodically with time) is formed between the contact charging member and the object to be charged, and the surface of the object to be charged is charged (AC application method). Can be charged easily.

  In addition, the contact charging device is a roller-type charger using a charging member as a roller-like member (charging roller) or a blade-type charging using a blade-like member (charging blade) according to the shape and form of the charging member brought into contact with an object to be charged. And a brush-type charger or the like, which is a charger and a brush-like member (charging brush) (see, for example, Patent Documents 1 to 4).

  The charging roller is rotatably supported by the bearing, is brought into pressure contact with the member to be charged at a predetermined pressure, and rotates as the member to be charged moves.

  The charging roller is usually a multilayer structure having a cored bar provided at the center as a base, a conductive elastic layer provided in a roller shape on the outer periphery of the cored bar, and a surface layer provided on the outer periphery thereof. .

  Among the above layers, the cored bar (metal layer) is a rigid body for maintaining the shape of the roller, and has a role as a feeding electrode.

In addition, the elastic layer usually has a volume resistivity of 10 ⁴ to 10 ⁹ Ω · cm, and a function to ensure uniform contact with the member to be charged by elastic deformation. A vulcanized rubber having a softness of 70 degrees or less with a rubber hardness (JIS A) imparted with conductivity is used. Conventional charging rollers include a foam type that uses a rubber foam (or sponge-like rubber) as an elastic layer and a solid type that does not use a rubber foam. The surface layer improves the charging uniformity of the object to be charged, prevents the occurrence of leaks due to pinholes on the surface of the object to be charged, and prevents the adhesion of toner particles, paper powder, etc. Has a function of preventing bleeding of softeners such as oil and plasticizer used to reduce the hardness of the elastic layer. The volume resistivity of the surface layer is usually 10 ⁵ to 10 ¹³ Ω · cm, and conventionally formed by applying a conductive paint or coating a seamless tube (see, for example, Patent Document 5). ).

  In the seamless tube manufacturing apparatus, the seamless tube is extruded by an extrusion process, and the seamless tube is manufactured in the order of an air cooling process, a water cooling sizing process, a tube taking process, and a tube cutting process. In the seamless tube thus obtained, when the resin wraps around in a cylindrical shape in the extrusion mold, at least one joined portion of the resin remains in the extrusion direction as a streak (hereinafter referred to as a weld).

  Such a weld line may cause subtle unevenness on the tube surface, and the unevenness tends to increase as the resin pressure during extrusion decreases.

Further, since the weld has a tendency that the weld portion has less inorganic pigment such as a conductive material, the resistance locally increases at the weld portion, and the resistance unevenness in the circumferential direction of the tube is increased. These resistance irregularities are recognized as image irregularities under the process conditions to be used, and there is a problem that they appear as horizontal black stripes on the image.
JP 56-91253 A JP-A 64-24264 JP 56-194349 A JP-A 64-24264 Japanese Patent Laid-Open No. 11-125952

  An object of the present invention is to provide a method for manufacturing a coated tube for a charging member in which unevenness of resistance is suppressed by reducing the level of occurrence of welds, and further, by coating the tube with an elastic body layer, the unevenness of resistance is reduced. It is an object of the present invention to provide a charging member that does not cause uneven image density and a cartridge for an electrophotographic apparatus and an electrophotographic apparatus equipped with the charging member.

The present invention provides a multi-layered seamless tube on an elastic body layer on the outer periphery of a metal core, which includes a step of extruding a tube in the direction of gravity, an air cooling step, a water cooling sizing step, a tube take-off step, and a tube cutting step. In the manufacturing method of the coated tube for a charging member that is coated to form a charging member,
The step of extruding is performed on the outlet portion (nipple) of the mold on the surface in contact with the coated tube on the side that becomes the inner surface of the coated tube and the outlet portion (die) on the surface of the mold in contact with the coated tube on the side that becomes the outer surface. A method of manufacturing a coated tube for a charging member, which is a step of mixing and extruding a resin using a mold in which at least one of them rotates.

  Further, the present invention provides at least an outlet portion (nipple) of a mold on a surface in contact with the coated tube on the inner surface side and an outlet portion (die) of the mold on a surface in contact with the coated tube on the outer surface side. One of the rotation speeds is 5-60 rpm, It is a manufacturing method of the said coating tube for charging members characterized by the above-mentioned.

  Further, according to the present invention, a charging member used as a charging means of an electrophotographic apparatus is obtained by coating a charging member-coated tube formed by the above-described method of manufacturing a charging member-coated tube on an elastic layer on a core metal outer periphery. This charging member is manufactured.

  According to another aspect of the present invention, there is provided a cartridge for an electrophotographic apparatus, wherein the cartridge for an electrophotographic apparatus to which the electrophotographic apparatus is detachable is mounted with the charging member.

  According to another aspect of the present invention, there is provided an electrophotographic apparatus comprising the electrophotographic apparatus cartridge.

  According to the present invention, in the manufacturing process of the coated tube for the charging member, by rotating the outlet portion of the extrusion mold, the resin is mixed in the mold, and the level of weld generation is reduced, thereby reducing resistance unevenness. A charging member that does not cause unevenness in image density due to uneven resistance by enabling the manufacturing method of the charged tube for charging member to be suppressed and further coats the tube with an elastic layer, and an electronic device equipped with the charging member It enabled a photographic device cartridge and an electrophotographic device.

  The present invention relates to a mold outlet portion (nipple) on the surface in contact with the coated tube on the inner surface side of the coated tube for charging member, and a mold outlet portion (die) on the surface in contact with the coated tube on the outer surface side. A method for producing a coated tube for a charging member having a step of mixing and extruding a resin using a mold in which at least one of them is rotated, and a charging member produced thereby, and an electrophotographic apparatus developed for application Cartridge and electrophotographic apparatus.

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

  FIG. 1 shows an example of a charging roller which is a charging member 1 'according to the present invention, which is used as a charger of an electrophotographic apparatus. This charging roller is provided with a foamed elastic body layer 2 made of a conductive elastic material on the outer periphery of a core metal 1 made of a highly conductive material such as stainless steel, plated iron, brass and conductive plastic. The outer circumference of the elastic layer 2 is covered with a tubular functional multilayer film (functional multilayer tube) 3. In the case of FIG. 1, the functional multi-layer tube is composed of an inner layer 3 (i) and an outer layer 3 (o).

  As the core metal (metal layer) in the present invention, for example, a good conductor such as aluminum, copper, iron, or an alloy containing these is preferably used. The metal core used in the present invention may be a metal tube having a thickness of about 0.1 to 1.5 mm, or may be a rod shape.

  As the conductive elastic material constituting the foamed elastic body layer 2, a foamed conductive rubber composition or a conductive polyurethane foam containing a conductive material can be used.

  In this case, the rubber component constituting the foamed conductive rubber composition is not particularly limited, but a conductive material is blended with ethylene-propylene-diene rubber (EPDM), chloroprene, chlorosulfonated polyethylene or the like. It is possible to suitably use a foam of a material, a foam of a copolymer rubber of epichlorohydrin and ethylene oxide, or a foam of a conductive rubber blended with a copolymer rubber of epichlorohydrin and ethylene oxide.

Examples of the conductive material blended in these rubber compositions include conductive powders such as carbon black, graphite, metals and various conductive metal oxides (such as tin oxide and titanium oxide), short carbon fibers and metal oxides. Various conductive fibers such as fibers can be used. The blending amount is preferably 3 to 100 parts by weight, particularly preferably 5 to 50 parts by weight with respect to 100 parts by weight of the total rubber component, and thereby the volume resistance of the foamed elastic layer 2 is 10 ¹ to 10 ⁹ Ω. -It is preferable to adjust to about cm. The foamed elastic body layer 2 can be formed by a known vulcanization molding method, and the thickness is appropriately set according to the use of the charging roller, but is usually preferably 1 to 20 mm.

  In the present invention, a functional multilayer film (functional multilayer tube) 3 is coated on the foamed elastic layer 2 in the form of a tube. In this case, the thermoplastic resin and elastomer constituting the functional multi-layer tube 3 may be any extrudable thermoplastic resin or elastomer, specifically, ethylene propylene rubber (EPDM). , Ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate, styrene butadiene rubber, polyester, polyurethane, nylon 6, nylon 66, nylon 11, nylon 12 and other copolymer nylon polyamides, styrene ethylene butyl, ethylene butyl, Ordinary rubber such as nitrile butadiene rubber, chlorosulfonated polyethylene, polysulfide rubber, chlorinated polyethylene, chloroprene rubber, butadiene rubber, 1,2-polybutadiene, isoprene rubber and polynorbornene rubber, steel Down - butadiene - styrene (SBS) and styrene - butadiene - it is possible to use a thermoplastic rubber such as styrene hydrogenated product (SEBS), it is not particularly limited.

  Alternatively, elastomers such as the above-mentioned resins and copolymers and elastomers such as modified products, polyethylene, polypropylene, polyether, polyamide, polycarbonate, polyacetal, polyurethane, polyphenylene oxide, polyvinyl acetate, polyvinylidene fluoride, polytetrafluoro Ethylene; saturated polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polystyrene, high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-ethylene / propylene rubber-styrene resin (AES) And styrene resins such as acrylonitrile-acrylic rubber-styrene resin (AAS), acrylic resins, vinyl chloride resins, vinyl chloride The combination of materials consisting of the resin and copolymers such as isopropylidene resin.

  Furthermore, a polymer alloy or polymer blend composed of two or more polymers selected from the rubber, thermoplastic elastomer and thermoplastic resin can also be used.

  The resin, elastomer, copolymer, and the like used for the functional multi-layer tube are those described above, and a tube configuration having desired characteristics can be obtained by appropriately blending a conductive material or the like.

  As the conductive material, known materials can be used, for example, carbon fine particles such as carbon black and graphite; metal fine particles such as nickel, silver, aluminum and copper; tin oxide, zinc oxide, titanium oxide, aluminum oxide and silica. Metal oxide fine particles doped with impurity ions with different valences; conductive fibers such as carbon fibers; metal fibers such as stainless steel fibers; the surface of carbon whiskers and potassium titanate whiskers are oxidized metal And conductive whisker such as conductive potassium titanate whisker that has been subjected to a conductive treatment with a material or carbon; and conductive polymer fine particles such as polyaniline or polypyrrole.

  The functional multi-layer tube used in the present invention is formed by extruding a conductive polymer composition comprising the above-mentioned various polymers, the above-mentioned conductive material and, if necessary, other additives.

  Furthermore, in order to obtain a film having a uniform film thickness of each thin film layer of the tube to be formed and a more uniform dispersibility of the conductive material or the like, a vertical tube extruder as shown in FIG. 2 is used in the present invention. use.

  If the functional multi-layer tube used in the present invention is simply molded, it can be obtained by forming a film into a tube by an extrusion molding method, an injection molding method, a blow molding method or the like. For example, for the purpose of obtaining superior durability, environmental resistance, and the like, the seamless tube obtained by the above various molding methods can be further crosslinked to form a conductive crosslinked polymer. As a method of cross-linking the conductive polymer formed into a tube shape, a cross-linking agent such as sulfur, organic peroxide and amines is added in advance according to the kind of the polymer, and the cross-linking is performed at a high temperature. A chemical cross-linking method for generating bismuth, a radiation cross-linking method for cross-linking by irradiating with radiation such as an electron beam or γ-ray is effective. Of the various crosslinking methods described above, the electron beam crosslinking method is preferred because there is no fear of contamination of the charged object due to the migration of the crosslinking agent or its decomposition product, and further, high-temperature treatment is not necessary and safety.

The volume resistance value of the functional multi-layer tube used in the present invention is preferably 10 ⁴ to 10 ¹⁰ Ω · cm, particularly preferably 10 ⁵ to 10 ⁹ Ω · cm.

  Further, in the present invention, the ultra-thin layer tube appropriately function-separated is integrally formed at the same time, so that each layer does not have an unnecessarily thick film, and the foamed elastic body can be used in the entire configuration. It is possible to effectively extract the flexibility of the layer.

  The functional multi-layer tube used in the present invention can be formed by various methods, and the extrusion method is suitable as described above. That is, a compound in which a polymer, a conductive material and, if necessary, a crosslinking agent, a stabilizer and other additives are mixed is manufactured in advance, and the compound is extruded from a die having a ring-shaped slit by an extruder and cooled. Can continuously produce seamless tubes (FIG. 2). A heat-shrinkable tube can be obtained if the tube diameter is expanded during cooling or after cooling and using a means such as air pressurization, and a non-heat-shrinkable tube can be obtained if no expansion treatment is performed.

  The functional multi-layer tube used in the present invention may be either non-heat-shrinkable or heat-shrinkable, but in the examples, a non-heat-shrinkable tube is used.

  In the case of a non-heat-shrinkable tube, the inner diameter of the tube needs to be equal to or less than the outer diameter of the foamed elastic layer in order to ensure the adhesion between the foamed elastic layer and the functional multilayer tube. The external fitting process is completed by inserting a foamed elastic body layer having a core in a state where the tube diameter is expanded by blowing compressed air and releasing the air pressure.

  On the other hand, in the case of a heat-shrinkable tube, the inner diameter of the tube is preferably larger than the outer diameter of the foamed elastic layer. After inserting the foamed elastic layer having a core metal, it is foamed by a method such as heating for a predetermined time in a thermostatic bath. The outer fitting process is completed by thermally shrinking the tube so as to be in close contact with the elastic layer. However, in the case of a heat-shrinkable tube, since the film thickness after shrinkage becomes the final film thickness of the functional multilayer film, an unexpected factor is easily included, and the film thickness and the uniformity of the dispersant are difficult to obtain. Therefore, in consideration of these points, for example, the dispersion conditions are made more stringent, or the application is performed under conditions reflecting the film thickness before and after shrinkage.

  The present invention provides a multi-layered seamless tube on an elastic body layer on the outer periphery of a metal core, which includes a step of extruding a tube in the direction of gravity, an air cooling step, a water cooling sizing step, a tube take-off step, and a tube cutting step. It is a manufacturing method of the covering tube for charging members which coat | covers and makes it a charging member.

  Next, a vertical extrusion apparatus used in the present invention will be described with reference to FIG. The die 4 used for molding is provided with inner and outer double annular extrusion channels 6 and 7 around a central through hole 5 for air introduction, and from the first extruder 8 to the inner channel 6 during molding. The inner layer elastomer composing the functional multi-layer tube and the outer layer elastomer composing the functional multi-layer tube from the second extruder 9 are pressure-injected into the outer flow path 7 respectively, and the inner layer 3 (i ) And the outer layer 3 (o) are superposed and extruded, cooled by a water-cooling ring 10 provided on the outer periphery of the functional multi-layer tube 3 obtained by air cooling, sent by a tube take-up device 21 and cut The device 23 is sequentially cut into a predetermined length, and the foamed elastic layer having the cored bar 1 is coated as a functional multi-layer tube for the charging roller in the next step. Reference numeral 24 is a mold, and 22 is a nipple.

  Here, the gist of the technique of the present invention will be described in more detail. FIG. 3 shows an example of a method for rotating the nipple and die used in the present invention. The nipple 22 of the mold 24 is rotated by a motor 25 attached to the tip of the central through hole 5 penetrating the mold center, and the die 4 is rotated by a motor 25 using a gear 26.

  FIG. 4 shows a state where the nipple 22 and the die 4 are rotating, with the mold exit portion looking up from below. The tube resin 3 near the nipple wall surface moves in the nipple rotation direction, and the tube resin near the die wall surface moves in the die rotation direction. For this reason, the mixing effect is more produced when the rotation direction of the nipple and the die is opposite.

  Further, the rotational speed of the nipple and the die is preferably 5 to 60 rpm, more preferably 20 to 30 rpm. If the rotation speed is less than 5 rpm, the expected mixing effect is difficult to obtain, and the weld tends to be clear. In high speed rotation, shear heat generation of the resin occurs, and the resin pressure decreases accordingly. In order to reduce such shear heat generation, it is also effective to set the temperature near the mold outlet lower or rotate only one of the nipple or the die. However, when it exceeds 60 rpm, it becomes difficult to keep the shape as a tube.

  The resistance unevenness in the tube circumferential direction obtained by this production method was found to be 1.3 or less.

  However, the value of the tube circumferential unevenness indicates the ratio of the DC current value max / DC current value min in one turn of the tube when the tube is passed through a stainless steel rod having a diameter slightly smaller than the tube diameter.

  Further, when the tube evaluation value of the tube circumferential unevenness is 1.3 or less, an image having a significantly better level of unevenness can be obtained as compared with the configuration in which the exit portion of the conventional extrusion mold is not rotated. It was.

  FIG. 5 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having a charging roller of the present invention.

  In FIG. 5, reference numeral 12 denotes an electrophotographic photosensitive member, which is rotationally driven in the direction of the arrow at a predetermined peripheral speed. In the rotation process, a positive or negative predetermined potential is uniformly applied to the peripheral surface by the charging member 1 'according to the present invention. Then, the exposure light 13 is received from exposure means (not shown) such as slit exposure or laser beam scanning exposure. Reference numeral 11 denotes a power source for the charging member 1 '. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 12.

  The formed electrostatic latent image is then developed with toner by the developing unit 14, and the developed toner developed image is rotated between the photoconductor 12 and the transfer unit 15 from a sheet feeding unit (not shown). The images are sequentially transferred by the transfer means 15 to the transfer material 16 that is fed in synchronization.

  The transfer material 16 that has received the image transfer is separated from the photoreceptor surface, introduced into the fixing means 17, and subjected to image fixing, thereby being printed out as a copy (copy).

  The surface of the photoconductor 12 after the image transfer is cleaned by the cleaning means 18 after removal of the transfer residual toner, and is repeatedly used for image formation.

  In the present invention, a plurality of components such as the electrophotographic photosensitive member 12, the charging member 1 ′, the developing unit 14, and the cleaning unit 18 are integrally combined as a process cartridge. It can be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, the developing unit 14 and the cleaning unit 18 are integrally supported together with the photosensitive member 12 and the charging member 1 ′ to form a cartridge, and a process cartridge 20 that can be attached to and detached from the apparatus main body using guide means such as a rail 19 of the apparatus main body. can do.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 13 is a reflected light or transmitted light from the original, or a signal is read from the original with a sensor, and the laser beam is scanned according to this signal. Light emitted by driving the LED array, driving the liquid crystal shutter array, or the like.

  More specifically, it demonstrates below with an Example and a comparative example.

“When the structure of a functional multi-layer tube is a resistance adjustment layer / conductivity control layer”
The resistance adjustment layer may be a resin whose material itself has an appropriate resistance value, or may be a resin whose resistance value is adjusted by mixing carbon. A multi-layered functional tube in which the material of each layer in this example is integrated by simultaneous extrusion can be formed. In the present invention, the tube is formed using a vertical extrusion device.

<Core>
The core metal was prepared by extruding an iron material into a bar material having a diameter of about 5 mm by cutting and cutting to a length of 260 mm, and then applying chemical plating to the thickness of about 3 μm.

<Formation of foamed elastic layer>
A vulcanizing agent and a foaming agent are blended with ethylene-propylene-diene rubber (EPDM), and the mixture is formed into a hose shape having an inner diameter of 4.5 mm and an outer diameter of 11.5 mm by an extrusion molding machine, and vulcanized can The foamed elastic body layer foamed inside was cut into a length of 225 mm, and the cored bar having a diameter of 5 mm and a length of 260 mm was inserted into the center hole.

<Formation of functional multi-layer tube>
As a material for the outer layer of the functional multi-layer tube, 100 parts by mass (61.3% by mass) of a styrene-based resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dynalon, JSR, melting point 100 ° C.) ), 20 parts by mass of polyethylene (12.3% by mass), trade name: Ketjen Black EC (manufactured by Lion Akzo) 12 parts by mass (7.4% by mass) and trade name: Special Black 250 (Degussa) 20 parts by mass (12.3% by mass), 10 parts by mass of magnesium oxide (6.1% by mass), and 1 part by mass of calcium stearate (0.6% by mass) were mixed in a V-type blender for several minutes. This was further melt-kneaded at 190 ° C. for 10 minutes using a pressure kneader. Furthermore, after cooling, it was pulverized by a pulverizer and pelletized by a single screw extruder.

  As materials for the inner layer, polyurethane elastomer (melting point: 120 ° C.) 100 parts by mass (76.3% by mass), carbon black (trade name: Ketjen Black EC) 20 parts by mass (15.3% by mass), magnesium oxide 10 parts by mass Parts (7.6% by mass) and 1 part by mass (0.8% by mass) of calcium stearate were pelletized in the same process as the material of the outer layer.

Example 1
Using a vertical extruder (a special order product manufactured by Plastic Giken Co., Ltd., see Fig. 2), the materials of these inner and outer layers are merged into a double layer with one crosshead (temperature 150 ° C), and a nipple It rotated in the reverse direction at the rotation number 20 rpm of 22 and the rotation number 20 rpm of the die | dye 4, respectively, and extruded into the cold water 10 of suitable temperature. After further cooling, the tube was taken up with a tube take-up device, and the tube was cut with a cutting machine. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm and a film thickness of 500 μm was obtained.

(Example 2)
A functional multi-layer tube having an inner diameter of about 12.0 mm and a film thickness of 500 μm was obtained in the same manner as in Example 1 except that only the die 4 was rotated at a rotation speed of 20 rpm.

(Example 3)
A functional multi-layer tube having an inner diameter of about 12.0 mm and a film thickness of 500 μm was obtained in the same manner as in Example 1 except that only the die 4 was rotated at a rotation speed of 1 rpm.

Example 4
A functional multi-layer tube having an inner diameter of about 12.0 mm and a film thickness of 500 μm was obtained in the same manner as in Example 1 except that only the die 4 was rotated at a rotational speed of 65 rpm.

(Comparative Example 1)
A functional multi-layer tube having an inner diameter of about 12.0 mm and a film thickness of 500 μm was obtained in the same manner as in Example 1 except that neither the nipple 22 nor the die 4 was rotated.

  Similar to the above, the circumferential unevenness of the obtained functional multi-layer tube is obtained by passing the tube through a stainless steel rod having a diameter slightly smaller than the tube diameter, and the ratio of the DC current value max / DC current value min in one turn of the tube. Indicated.

<Production of charging roller>
The outer periphery of the foamed elastic layer was fitted into the functional multi-layer tube obtained by the above method using a tube coating device (not shown), and pressure-adhered.

  As a result of image formation using this charging roller as a primary charger of an LBP (laser beam printer; laser jet 2-P manufactured by Hewlett Packard), a gap is formed between the functional multi-layer tube 3 and the foamed elastic layer 2. No occurrence of wrinkles, no wrinkles on the functional multi-layer tube 3, and a good image without image unevenness was obtained.

このように、実施例１、２、３、４及び比較例１の帯電部材が組み込まれたプロセスカートリッジを用いた電子写真装置による評価も行っている。但し、実施例は、従来の押し出し金型の出口部分を回転させていない比較例より、格段に良いとして◎とし、比較例は、不適合とまではいかないので○としている。

As described above, evaluation by an electrophotographic apparatus using a process cartridge in which the charging members of Examples 1, 2, 3, 4 and Comparative Example 1 are incorporated is also performed. However, in the example, ◎ is markedly better than the comparative example in which the exit portion of the conventional extrusion mold is not rotated, and the comparative example is marked as ◯ because it is not incompatible.

It is a longitudinal cross-sectional view of an example of the charging member of this invention. It is a longitudinal cross-sectional view of an example of the vertical extruder of the coating tube for charging members used for this invention. It is a schematic diagram of the rotation method of the nipple and die used for this invention. It is a schematic diagram in which the nipple and die used for this invention are rotating. 1 is a schematic configuration diagram of an electrophotographic apparatus having a process cartridge having a charging roller of the present invention.

Explanation of symbols

1 Core (metal layer)
1 'Charging member 2 Elastic foam layer 3 Functional multilayer film (functional multilayer)
3 (i) Inner layer 3 (o) Outer layer 4 Die 5 Center through hole 6 Extrusion channel 7 Extrusion channel 8 First extruder 9 Second extruder 10 Water-cooling ring 11 Power supply 12 Photoconductor 13 Exposure light 14 Development Means 15 Transfer means 16 Transfer material 17 Fixing means 18 Cleaning means 19 Rail 20 Process cartridge 21 Take-up process 22 Nipple 23 Cutting process 24 Mold 25 Motor 26 Gear

Claims (5)

Charging by covering multiple layers of seamless tubes on the elastic body layer on the outer periphery of the metal core, which has a process of extruding the tube in the direction of gravity, air cooling process, water cooling sizing process, tube taking process, and tube cutting process In the method of manufacturing a coated tube for a charging member as a member,
The extruding step is such that at least one of the mold exit portion on the surface in contact with the coating tube on the inner surface side of the coating tube and the mold exit portion on the surface in contact with the coating tube on the outer surface side rotates. A method for producing a coated tube for a charging member, which is a step of mixing and extruding a resin using a mold.   The number of rotations of at least one of the outlet portion of the mold on the surface in contact with the coated tube on the inner surface side and the outlet portion of the mold on the surface in contact with the coated tube on the outer surface side is 5 to 60 rpm. The manufacturing method of the covering tube for charging members of Claim 1 characterized by these.   The charging member used as the charging means of the electrophotographic apparatus covers the elastic member layer on the outer periphery of the cored bar with the charging member covering tube formed by the manufacturing method of the charging member covering tube according to claim 1 or 2. A charging member characterized by being manufactured in the above manner.   An electrophotographic apparatus cartridge, wherein the electrophotographic apparatus cartridge, to which the electrophotographic apparatus is detachably mounted, mounts the charging member according to claim 3. An electrophotographic apparatus comprising the electrophotographic apparatus cartridge according to claim 4.

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