JP2006215389A - Method for manufacturing charging-member cover tube, charging member, electrophotographic apparatus cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing charging-member cover tubes, in which the problems relating to the perpendicularity of seamless tubes and variations in outside diameter are solved by minimizing vibration and wastage of cut parts, which arise by the cutting mechanism of a tube manufacturing process, and by performing a cutting operation without stopping the feed of tubes. <P>SOLUTION: The method for manufacturing charging-member cover tubes includes a mechanism for pushing out a tube in the direction of the gravity, a cooling mechanism, a water-cooling sizing mechanism, a tube pulling and receiving mechanism, and a tube cutting mechanism. The method is used for forming charging members by covering an elastic body on the periphery of a metal core with a plurality of seamless tubes formed in layers. In the method, the tube cutting mechanism runs in synchronization with the tube pulling and receiving mechanism. The charging members are obtained by this method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 by applying a voltage, and a method for manufacturing the coated tube. 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. It is roughly classified into a brush-type charger and the like, which are a charger and a brush-like member (charging brush) (for example, see Patent Documents 1 and 2).

  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 that ensures 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 3). ).

  In the seamless tube manufacturing apparatus, the seamless tube is pushed out by an extruding mechanism, and the seamless tube is manufactured in the order of an air cooling mechanism, a water cooling sizing mechanism, a tube take-up mechanism, and a tube cutting mechanism. When the tube is in contact with the tube, vibration during cutting is transmitted to the tube before water-cooled sizing and the tube undulates, or the tube feed is stopped for a moment, resulting in a slight difference in the tube outer diameter. There was a problem (pulsation occurred).

  When the tube cutting mechanism is of a non-contact type such as a laser, the tube is fed even during cutting, so that the cut surface of the tube is slanted, and there is a waste that an unusable part is generated.

  It has been found that when the tube take-up mechanism is changed from a belt type to a roller type, the take-up accuracy is improved (for example, see Patent Document 4). However, if a roller type take-up machine is used, the number of contacts with the tube is reduced, so that vibrations are more easily transmitted and there is a concern that slipping is likely to occur when feeding is stopped.

  When the tube is thin, the vibration tends to be transmitted more easily as the diameter increases.

  In order to suppress these vibrations, if at least one cutting vibration suppression device is attached after the water-cooled sizing mechanism, the vibration is reduced, but if it is strongly suppressed, the tube feed is stopped and the vibration is completely blocked. It was not reached.

  When the tube outer diameter unevenness is large, it suggests that the thickness is uneven, and when this is covered, the thickness unevenness of the seamless tube becomes a difference in tightness in the case of the soft foamed elastic layer below it. Resistance unevenness occurs, and as a result, it is recognized as image unevenness.

Further, when the seamless tube that is bent and taken up is covered, the roller influences according to the bending. That is, it was thought that this occurred because the shape of the roller after coating exhibited the low straightness of the seamless tube, and the level was recognized as image unevenness under the process conditions used.
JP 56-91253 A JP-A 64-24264 Japanese Patent Laid-Open No. 11-125952 JP 2003-71902 A

  The object of the present invention is to suppress vibrations generated by the cutting mechanism in the process of manufacturing the coated tube and waste of the cutting portion, and to cut the tube without stopping the tube feed. Provided is a method for producing a coated tube for a charging member, and further provides a charging member that has a seamless tube longitudinal shape that is coated on an elastic body layer and that has a substantially straight outer diameter and suppresses uneven outer diameter, and an electrophotographic apparatus equipped with the charging member Cartridge and electrophotographic apparatus.

In accordance with the present invention, a charging member in which an elastic body on the outer periphery of a metal core is coated with a plurality of seamless tubes, having a mechanism for extruding a tube in the direction of gravity, an air cooling mechanism, a water cooling sizing mechanism, a tube take-up mechanism, and a tube cutting mechanism. In the method for producing a coated tube for a charging member,
This is solved by a method for manufacturing a coated tube for a charging member, which has the tube cutting mechanism that runs in synchronization with the tube take-up mechanism.

  Further, the tube cutting mechanism of the present invention is solved by a method for manufacturing a coated tube for a charging member, which is equipped with a tube chuck means that contacts at least two points with the tube.

  Further, according to the present invention, the charging member used for the charging mechanism of the electrophotographic apparatus is formed by covering the charging member-coated tube obtained by the above-described charging member-coated tube manufacturing method on an elastic body formed on a core metal. This is solved by the charging member characterized by the above.

  In addition, according to the present invention, the problem is solved by a cartridge for an electrophotographic apparatus and an electrophotographic apparatus on which the charging member is mounted.

  According to the present invention, the vibrations generated by the cutting mechanism in the process of manufacturing the coated tube and the waste of the cutting part are suppressed, and the tube is cut without stopping the feeding, so that the straightness of the seamless tube and the outer diameter unevenness are solved. Provided is a method for producing a coated tube for a charging member, and further provides a charging member that has a seamless tube longitudinal shape that is coated on an elastic body layer and that has a substantially straight outer diameter and suppresses uneven outer diameter, and an electrophotographic apparatus equipped with the charging member Cartridge and electrophotographic apparatus can be obtained.

  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 periphery of the elastic layer 2 is covered with a tubular functional multilayer film 3 (hereinafter, functional multilayer tube). In the case of FIG. 1, the functional multi-layer tube prevents the plasticizer from bleeding out from the foamed elastic layer 2, and is an internal layer that is a layer for controlling resistance that governs the electrical characteristics of the electrode layer or the charging roller. It comprises a layer 3 (i) and an outer layer 3 (o) which is a surface layer for preventing a charged body such as a photoreceptor from being scratched or contaminated.

  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 core bar used in the present invention may be a metal tube having a diameter of about 4 to 10 mm and a thickness of about 0.1 to 1.5 mm, or may have 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 foams such as ethylene-propylene-diene rubber (EPDM), chloroprene, chlorosulfonated polyethylene, and epichlorohydrin A foam of a copolymer rubber with ethylene oxide or a foam of a conductive rubber blended with a copolymer rubber of epichlorohydrin and ethylene oxide can be suitably used.

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 thermoplastic resin or elastomer that can be extruded, and specifically, ethylene propylene rubber (EPM). , Ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl acrylate copolymer, styrene butadiene rubber, polyester, polyurethane, nylon 6, nylon 66, nylon 11, nylon 12, and other copolymer nylon, etc. Polyamide, hydrogenated styrene copolymer, ethylene butyl copolymer, nitrile butadiene rubber, chlorosulfonated polyethylene, polysulfide rubber, chlorinated polyethylene, chloroprene rubber, butadiene rubber, 1,2-polybutadiene rubber, isoprene rubber and polyethylene Conventional rubber, such as norbornene rubber, styrene - butadiene - styrene (SBS) and styrene - butadiene - it is possible to use a thermoplastic rubber such as styrene hydrogenated product (SEBS), 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 There is isopropylidene resin, or the like.

  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.

  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.

  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, and 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 has a mechanism for extruding a tube in the direction of gravity, an air cooling mechanism, a water cooling sizing mechanism, a tube take-off mechanism, and a tube cutting mechanism, and is charged by covering a plurality of layers of seamless small-diameter thin tubes on an elastic body on the outer periphery of a cored bar. The charging member-coated tube manufacturing apparatus as a member uses a charging member-coated tube manufacturing apparatus having a tube cutting mechanism that runs in synchronization with the tube take-up mechanism.

  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 polymer for the inner layer constituting the functional multi-layer tube and the polymer for the outer layer constituting the functional multi-layer tube from the second extruder 9 were injected into the outer flow path 7 under pressure, respectively. ) And the outer layer 3 (o) are integrated and extruded and cooled by a water-cooling ring 10 provided on the outer periphery of the functional multi-layer tube 3, which is sent by a tube take-up device 21 and has a predetermined length. In the next step, the foamed elastic layer having the cored bar 1 is coated as a functional multi-layer tube for the charging roller.

  Here, the gist of the technique of the present invention will be described in more detail. The synchronous traveling type cutting machine 23 in the extrusion apparatus of FIG. 2 shows an example of an apparatus used in the present invention. As a tuning method, for example, the cutting machine main body 23 is not self-propelled in the pushing direction by a synchronous drive motor that has received the same speed command as the rotational speed command of the take-up machine 21, and thus the cutting is performed by the rotating teeth. Quickly return to the standby position after cutting. The tuning speed (take-off speed) here depends on the extrusion ability, tube diameter, film thickness, etc. of the extruder, but is about 0.5 m / min to 20 m / min, preferably about 1 m / min to 5 m / min. is there. The slower the tuning speed (take-off speed), the thinner the effect of tuning that does not stop feeding, and the faster the speed, the greater the vibration during running.

  FIG. 3 (a) is a schematic view of a state in which when the cutting machine is a contact type such as a rotating tooth, the tube feed is stopped for a moment, the tube outer diameter is partially increased, and the tube has a subtle difference in outer diameter. FIG. FIG. 3 (b) is a schematic view of a state in which when the cutting machine is a non-contact type such as a laser, the cut surface is inclined because the tube continues to be fed even during cutting, and an unusable part is generated. FIG.

  FIG. 4A shows a case where the cutting machine is a contact type such as a rotating tooth, in which the tube chuck means for contacting at least two points with the tube is not provided, and FIG. 4B is provided. The state of vibration at the time of cutting in the case is shown. For the first time, it became possible to firmly suppress vibration without stopping the tube feed.

  When the tube straightness and tube outer diameter unevenness obtained by this production method were determined, the straightness was 1.5 mm or less and the outer diameter unevenness was 0.5% or less.

  However, as shown in FIG. 5, the tube outer diameter unevenness is measured by passing the tube through a stainless steel rod having a diameter slightly smaller than the tube diameter, and rotating at five outer diameter measuring positions in the tube longitudinal direction. A 100 fraction value (Δ / Da × 100) of the difference Δ between the maximum value and the minimum value of the average value of the outer diameters at three locations in the circumferential direction and the average value Da of all the outer diameter measurement values was obtained. As shown in FIG. 6, the straightness of the tube was measured by measuring the diameter Xa of the end of the tube and the maximum tube bending width Xb perpendicular to the cut surface of the end. When the straightness of the tube is ΔX, ΔX = Xb−Xa.

  When the tube outer diameter unevenness is large, it suggests that the thickness is uneven, and when this is covered, the thickness unevenness of the seamless tube becomes a difference in tightness in the case of the soft foamed elastic layer below it. Resistance unevenness occurs, and as a result, it is recognized as image unevenness.

  Further, when the seamless tube that is bent and taken up is covered, the roller influences according to the bending. That is, it was thought that this occurred because the shape of the roller after coating exhibited the low straightness of the seamless tube, and the level was recognized as image unevenness under the process conditions used.

  Image evaluation of a tube having a straightness of 1.5 mm or less and an outer diameter non-uniformity of 0.5% or less obtained by this manufacturing method showed a much better level of unevenness than the currently applied configuration. No image was obtained.

  FIG. 7 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having a charging roller of the present invention.

  In FIG. 7, 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. 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, this will be described below with examples and comparative examples.

“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 multilayer 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 materials for the outer layer of the functional multi-layer tube, 100 parts by mass (61.3% by mass) of hydrogenated styrene copolymer resin (trade name: Dynalon, manufactured by JSR), polyethylene (trade name: manufactured by Petrocene, manufactured by Tosoh Corporation) ) 20 parts by mass (12.3% by mass), carbon black (trade name: Ketjen Black EC, manufactured by Lion Akzo) 12 parts by mass (7.4% by mass) and acidic carbon black (trade name: Special Black 250, Degussa) 20 parts by mass (12.3% by mass), magnesium oxide (trade name: Starmag, manufactured by Kamishima Chemical Co.) 10 parts by mass (6.1% by mass), calcium stearate (manufactured by Kishida Chemical) 1 part by mass (0.6% by mass) was mixed with 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, 100 parts by mass (76.3% by mass) of polyurethane elastomer (trade name: Kuramilon, manufactured by Kuraray Co., Ltd.), 20 parts by mass of carbon black (trade name: Ketjen Black EC, manufactured by Lion Akzo) (15 3 mass%), magnesium oxide (trade name: Starmag, manufactured by Kamishima Chemical Co., Ltd.) 10 mass parts (7.6 mass%) and calcium stearate (produced by Kishida Chemical Co., Ltd.) 1 mass part (0.8 mass%), It was pelletized in the same process as the material of the outer layer.

Example 1
Using a vertical extruder (special 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, and the die 4 has a temperature of 155 ° C. Then, the solution was extruded into cold water 10 having an appropriate temperature and further cooled, and then taken out at a take-up speed of 2 m / min with a tube take-up device. The tube was cut at a traveling speed of 2 m / min with a synchronous traveling type cutting machine using rotating teeth with chuck means as shown in FIG. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm was obtained.

(Example 2)
After the tube was taken up at a take-up speed of 2 m / min in the same procedure as in Example 1, the tube was run at a running speed of 2 m / min with a synchronous running type cutting machine with rotating teeth without chuck means as shown in FIG. Was cut off. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm was obtained.

(Example 3)
After taking the tube at a take-off speed of 0.5 m / min in the same procedure as in Example 1, the running speed is 0.5 m / min with a synchronous running cutting machine with rotating teeth with chuck means as shown in FIG. The tube was cut in min. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm was obtained.

Example 4
After taking up the tube at a take-up speed of 7 m / min in the same procedure as in Example 1, the tube is moved at a running speed of 7 m / min with a synchronous running cutting machine with rotating teeth with chuck means as shown in FIG. Disconnected. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm was obtained.

(Comparative Example 1)
After the tube was taken out in the same procedure as in Example 1, the tube was cut with a fixed cutting machine with rotating teeth without chuck means. In this way, a functional multi-layer tube having an inner diameter of about 12.0 mm was obtained.

  The outer diameter unevenness and straightness of the obtained functional multi-layer tube were measured.

<Production of charging roller>
The outer periphery of the foamed elastic layer was fitted into the foamed elastic layered tube obtained by the above method using a tube coating apparatus (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 good images without image unevenness were obtained.

  As described above, evaluation by an electrophotographic apparatus using the process cartridge in which the charging members of Examples 1 and 2 and Comparative Example 1 are incorporated is also performed. However, the case according to the present invention is marked as “◎” because it is much better than the currently applied configuration, and the current case is marked as “◯” because it is not a nonconformity.

It is a vertical front view of an example of the charging member of the present invention. It is a vertical front view of an example of the vertical type extruder of the functional multi-layer tube used for this invention. It is the schematic diagram showing the problem of the conventional fixed cutting mechanism used for this invention. It is a schematic diagram of the cutting vibration with and without the nip means in the synchronous traveling cutting mechanism of the present invention. It is explanatory drawing of the measuring method of the outer diameter nonuniformity of the tube used for this invention. It is explanatory drawing of the measuring method of the straightness of the tube used for this invention. 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)
DESCRIPTION OF SYMBOLS 1 'Charging member 2 Foam elastic body layer 3 Functional multilayer tube 3 (i) Inner layer 3 (o) Outer layer 4 Die 5 Center through-hole 6 Extrusion flow path 7 Extrusion flow path 8 First extruder 9 Second push Ejector 10 Water-cooled ring 11 Power source 12 Photoconductor 13 Exposure light 14 Developing means 15 Transfer means 16 Transfer material 17 Fixing means 18 Cleaning means 19 Rail 20 Process cartridge 21 Pickup mechanism 22 Chuck means attached to the cutting mechanism 23 Cutting mechanism 24 Stainless steel rod

Claims (5)

Charging as a charging member by covering the elastic body on the outer periphery of the metal core with multiple layers of seamless tubes, which has at least a mechanism for pushing the tube in the direction of gravity, an air cooling mechanism, a water cooling sizing mechanism, a tube take-off mechanism, and a tube cutting mechanism In the method for producing a coated tube for a member,
A method for producing a coated tube for a charging member, comprising the tube cutting mechanism that travels in synchronization with a take-up speed of the tube take-up mechanism.   2. The method for producing a coated tube for a charging member according to claim 1, wherein the tube cutting mechanism is equipped with a tube chuck means that contacts at least two points with the tube.   A charging member used for a charging mechanism of an electrophotographic apparatus is formed by covering a charging member-coated tube obtained by the method for manufacturing a charging member-coated tube according to claim 1 or 2 on an elastic body formed on a cored bar. A charging member.   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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