JP2002169356A - Method for manufacturing electrifying roller and electrifying roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrifying roller and the electrifying roller using a vertical type extruded tube by which the resistance value of design is obtained in spite of the application of much conductive material ordinarily causing low resistance, and an excellent image having no defect such as image irregularity is obtained. SOLUTION: In this method for manufacturing the electrifying roller using a functional double-layer tube obtained by the vertical type extrusion of the double-layer simultaneous molding having a tube extrusion stage, a tube cooling stage and a tube pull-in stage in a gravity direction, the amount of the conductive material in the composition of the external layer component of the functional double-layer tube is 5 to 28 mass %, and the amount of the conductive material in the composition of an internal layer component is 5 to 35 mass %, and extrusion molding temperature (temperature of a die) in the case of extracting the material in the composition is 140 to 200 deg.C. Then, the electrifying roller using the vertical type extruded tube is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging roller which is placed in contact with an object to be charged and charges the object by applying a voltage, and a method of manufacturing the charging roller.

[0002]

2. Description of the Related Art In recent years, as a charging means used in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, a charging means of a contact charging system has been adopted. Contact charging is to charge a charged body to a predetermined polarity and potential by applying a voltage to a charging member arranged in contact with the charged body, and it is possible to lower the voltage of a power supply, such as ozone. it is possible to reduce the occurrence of corona products, and there are advantages such as can be achieved a simple and low cost structure.

[0003] Voltage applied to the charging member, in addition to at least twice the peak of the charge starting voltage of the member to be charged at the time of applying to the contact charging member a direct current voltage of method of applying only a direct current (DC application type) A method of charging a surface of an object to be charged by forming an oscillating electric field having an inter-voltage (an electric field whose voltage value periodically changes with time) between the contact charging member and the object to be charged (AC
Application method), and the latter can be more uniformly charged.

Further, the contact charging device is based on a roller type charging device using a charging member as a roller-shaped member (charging roller) (Japanese Patent Laid-Open Publication No. Sho 63-163).
7380 and JP-A-56-91253, and a blade-type charger (JP-A-64-24264 and JP-A-56-19) as a blade-shaped member (charging blade).
4349) and a brush type charger (eg, Japanese Patent Application Laid-Open No. 64-24264) using a brush-shaped member (charging brush).

[0005] The charging roller is rotatably bearing support is pressed against a predetermined pressure to the member to be charged, it is rotated with the movement of the member to be charged.

[0006] The above-mentioned charging roller is generally a multilayer having a core provided as a base, a conductive elastic layer provided in a roller shape on the outer periphery of the core, and an outer layer provided on the outer periphery. It is a structure.

[0007] Among the above layers, the core metal (metal layer) is a rigid body for maintaining the shape of the roller and also has a role as a power supply electrode.

[0008] The elastic layer usually has a thickness of 10 ⁴ to 10 ^9.
Since it is required to have a volume specific resistance of Ω · cm and a function of ensuring uniform contact with the member to be charged by being elastically deformed, a rubber hardness (JIS A) to which conductivity is imparted is usually 70. Vulcanized rubber having a flexibility of less than or equal to ° is used. Conventional charging rollers include a foaming type using a rubber foam (or sponge-like rubber) as an elastic layer and a solid type not using a rubber foam. In addition, the outer layer improves the charging uniformity of the member to be charged, prevents the occurrence of leaks due to pinholes or the like on the surface of the member to be charged, and has a function of preventing sticking of toner particles and paper powder. Has a function of preventing bleeding of a softening agent such as an oil or a plasticizer used for lowering the hardness of the elastic layer. The volume resistivity of the outer layer is usually 10 ⁵ to 10 ¹³ Ω · cm, and has conventionally been formed by applying a conductive paint or covering a seamless tube.

As a method of manufacturing the tube-coated roller,
There is a method using a heat-shrinkable tube and a method using a non-heat-shrinkable tube. When using a heat-shrinkable tube, insert a metal core or an elastic roller with an elastic body formed on the metal core into a heat-shrinkable tube with a primer applied on the inner surface, and heat the entire tube to shrink the tube to make the roller Cover the outer circumference. When a non-heat-shrinkable tube is used, the non-heat-shrinkable tube is placed on the inner wall of the cylindrical mold while being pulled in the longitudinal direction, and the pressure between the tube and the inner wall of the cylindrical mold is reduced to form the inner wall of the tube. Then, after inserting an elastic roller having an elastic body formed on the outer periphery of the cored bar, the tube was coated on the outer periphery of the roller by heat fusion.

However, when using a heat-shrinkable tube,
Although the manufacturing process is simple, it is difficult to manufacture the heat-shrinkable tube, and uneven wall thickness is inevitable and expensive. Also,
Adjustment of shrinkage is also difficult, and there are problems such as wrinkles. When a non-heat-shrinkable tube is used, a non-heat-shrinkable tube having a uniform thickness without uneven thickness can be obtained at a low cost, but the production of a roller having a multilayered outer layer requires skill in the process. Problems such as wrinkling and twisting of the tube were liable to occur.

On the other hand, when the multilayer portion is formed of a tube, problems such as pinholes can be avoided, and the control of the film thickness is relatively easy. However, in the case of a conventional tube, it is very difficult to form a tube having a thin film thickness of 30 μm or less. Therefore, a multilayer resistive layer is prepared by preparing a plurality of single-layer tubes and externally fitting them one by one.
When they are formed in a superposed manner, the thickness of the entire resistance layer is increased, so that it is difficult to obtain a roller having a desired resistance value.

[0012]

Accordingly, a method for simultaneously molding the above-mentioned multilayer tube (Japanese Patent Laid-Open No. 11-125952).
However, even in this case, if the amount of carbon black as a conductive material to be contained in order to obtain a desired resistance value is small, when the tube is covered, it may be caused by uneven dispersion in the circumferential direction of the roller. Probably uneven resistance occurs,
There is a disadvantage that the image directly becomes defective. Further, when the amount of carbon black is increased to solve this problem, there is a disadvantage that the resistance value becomes lower than a desired value.

An object of the present invention is to make it possible to obtain a designed resistance value despite the addition of a large amount of conductive material which usually leads to a reduction in resistance, and to obtain a vertical type image having no defects such as image unevenness. An object of the present invention is to provide a method for manufacturing a charging roller using an extrusion tube and a charging roller.

[0014]

According to the present invention, there is provided a charging roller using a functional multi-layer tube by vertical extrusion of a multi-layer simultaneous molding having a tube extruding step, a tube cooling step, and a tube pulling step in the direction of gravity. In the production method, the amount of the conductive material in the composition of the outer layer component of the functional multilayer tube is 5% by mass to 28% by mass, and the amount of the conductive material in the composition of the inner layer component is 5% by mass. ~ 35
Mass%, and a method for manufacturing a charging roller using a vertical extrusion tube, wherein an extrusion molding temperature (die temperature) at the time of extruding the composition is 140 ° C. to 200 ° C. .

Further, according to the present invention, there is provided a charging roller having a conductive elastic layer and a functional multi-layer provided on a cored bar,
There is provided a charging roller in which the functional multilayer is formed by the method for manufacturing a charging roller.

[0016]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows an example of the charging roller 1 'of the present invention, which is used as a charger of an electrophotographic apparatus. This charging roller is provided with a foamed elastic layer 2 made of a conductive elastic material on the outer periphery of a cored bar 1 made of a good conductive material such as stainless steel, plated iron, brass and conductive plastic. The outer periphery of the elastic layer 2 is coated with a tubular functional multilayer film 3.
In the case of FIG. 1, the functional multilayer film includes an inner layer 3 (i) and an outer layer 3 (o).

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

In this case, the rubber component constituting the foamed conductive rubber composition is not particularly limited.
Ethylene-propylene-diene rubber (EPDM), chloroprene, chlorosulfonated polyethylene blended with conductive material, foam, copolymer rubber of epichlorohydrin and ethylene oxide or copolymer rubber of epichlorohydrin and ethylene oxide A foam containing a conductive material can be suitably used.

Examples of the conductive material to be added to these rubber compositions include conductive powders such as carbon black, graphite, metal and various conductive metal oxides (such as tin oxide and titanium oxide), carbon fiber and metal oxide. Various conductive fibers such as short fibers of the product can be used. The compounding amount is preferably 3 to 100 parts by mass, particularly preferably 5 to 50 parts by mass with respect to 100 parts by mass of the total rubber component, whereby 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 layer 2 can be formed by a known vulcanization molding method.
The thickness is appropriately set according to the use of the charging roller and the like, but is usually preferably 1 to 20 mm.

In the present invention, a functional multilayer film 3 is coated on the foamed elastic layer 2 in the form of a tube. In this case, the thermoplastic resin constituting the functional multilayer film 3 may be any thermoplastic resin that can be extruded, and specifically, ethylene propylene rubber (E
PDM), ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate, styrene butadiene rubber, polyester, polyurethane, polyamide (nylon 6, nylon 66, nylon 11, nylon 12)
And other copolymerized nylons), styrene ethylene butyl, ethylene butyl, nitrile butadiene rubber, chlorosulfonated polyethylene, polysulfide rubber, chlorinated polyethylene, chloroprene rubber, butadiene rubber, 1,2-
Conventional rubbers such as polybutadiene, isoprene rubber and polynorbornene rubber, and thermoplastic rubbers such as styrene-butadiene-styrene (SBS) and styrene-butadiene-styrene water additive (SEBS) can be used, with particular limitations. It is not something to be done.

Alternatively, elastomers such as the above-mentioned resins and copolymers and modified elastomers, and polyethylene, polypropylene, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT)
Such as saturated polyester, polyether, polyamide, polycarbonate, polyacetal, acrylonitrile butadiene styrene, polystyrene, high impact polystyrene (HIPS), polyurethane, polyphenylene oxide, polyvinyl acetate, polyvinylidene fluoride,
Polytetrafluoroethylene, acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-
Ethylene / propylene rubber-styrene resin (AES) and acrylonitrile-acrylic rubber-styrene resin (A
A combination of a resin and a material made of a copolymer such as a styrene resin such as AS), an acrylic resin, a vinyl chloride resin and a vinylidene chloride resin is preferable.

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 a rod.

Next, the functional multi-layer tube used in the present invention will be described. The functional multi-layer tube in the present invention is a polymer previously formed in the form of a seamless tube, and is externally fitted to the foamed elastic layer on the outer periphery of the core metal (metal layer), and is tightly covered. .

For example, the functional multilayer tube 3 having a desired number of layers can be formed by one operation using the apparatus shown in FIG. 2 (a) is for two types and two layers, (b) is for two types and three layers, and (c) is for three types and three layers.

The resin, elastomer, copolymer and the like used in this case are as described above, and a tube structure having desired characteristics can be obtained by appropriately blending a conductive material and the like described later.

Further, a polymer alloy or a polymer blend comprising two or more kinds of polymers selected from the above rubbers, thermoplastic elastomers and thermoplastic resins can also be used.

The functional multi-layer tube of the present invention is formed by forming a conductive polymer composition comprising the above-mentioned various polymers, the following conductive material and, if necessary, other additives into a tube by extrusion molding. Can be obtained by

Further, in order to obtain a uniform thickness of each thin film layer of the formed tube and a more uniform dispersibility of the conductive material and the like, a vertical tube extruder (FIG. 3) is used. I do.

[0030] As the above conductive material, known materials can be used, for example, carbon particles such as carbon black and graphite; nickel, silver, metal particles such as aluminum and copper; tin oxide, zinc oxide, titanium oxide, Conductive metal oxide fine particles containing aluminum oxide and silica as main components and doped with impurity ions having different valences; conductive fibers such as carbon fibers; metal fibers such as stainless steel fibers; carbon whiskers and potassium titanate whiskers Conductive whisker such as conductive potassium titanate whisker whose surface is made conductive with metal oxide or carbon; and conductive polymer fine particles such as polyaniline and polypyrrole. Among the various conductive agents, carbon black is preferred.

[0031] In addition, carbon black, the DBP oil absorption 300~500cm ³ / 100g carbon black,
DBP oil absorption of 150 cm ^3/100 g or less and pH is particularly preferably 5 or less acidic carbon black.

The functional multi-layer tube used in the present invention can be further cross-linked to form a conductive cross-linked polymer in order to obtain better durability and environmental resistance. As a method for cross-linking a conductive polymer formed in a tubular shape, a cross-linking agent such as sulfur, an organic peroxide and an amine is added in advance depending on the type of the polymer, and cross-linking is performed at a high temperature. Is effective, and a radiation cross-linking method of cross-linking by irradiation with radiation such as an electron beam or γ-ray is effective. Among the various cross-linking methods, the electron beam cross-linking method has no risk of contamination of the charged member due to migration of a cross-linking agent or a decomposition product thereof.
This is preferable in that there is no need for high-temperature treatment and safety.

The functional multilayer tube used in the present invention preferably has a volume resistivity of 10 ⁴ to 10 ¹⁰ Ω · cm, and particularly preferably 10 ⁵ to 10 ⁹ Ω · cm. Specifically, the amount of the conductive material in the composition of the outer layer component of the functional multilayer tube is 5% by mass to 28% by mass, particularly preferably 13.2% by mass to 25.6% by mass, and The amount of the conductive material in the composition of the inner layer component is 5% by mass to 35% by mass.
In particular, 8.3% by mass to 28.8% by mass is preferable,
The extrusion molding temperature (die temperature) when extruding the composition is 140 ° C to 200 ° C.

Further, in the present invention, since the tubes of the ultra-thin layers which are appropriately separated in function are integrally formed at the same time, each layer does not need to be unnecessarily thick, and It is possible to effectively bring out the flexibility of the foamed elastic layer.

In the extrusion method, which is a method for forming a functional multilayer tube used in the present invention, a compound in which a polymer, a conductive material and, if necessary, a crosslinking agent, a stabilizer and other additives are mixed in advance is used. After the compound is manufactured, the compound is extruded from a die having a ring-shaped slit by an extruder and cooled, whereby a seamless tube can be manufactured continuously (FIG. 3). If the tube diameter is expanded during cooling or after cooling and then reheated to increase the tube diameter using a means such as air pressurization, a heat-shrinkable tube can be obtained.

The seamless tube used in the present invention may be either non-heat-shrinkable or heat-shrinkable.
In embodiments described later, a non-heat-shrinkable material is employed.

In the case of a non-heat-shrinkable tube, it is necessary that the inner diameter of the tube be equal to or less than the outer diameter of the foamed elastic layer in order to secure the adhesion between the foamed elastic layer and the functional multilayer tube. The outer fitting process is completed by inserting a foamed elastic body layer having a metal core with the tube diameter 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 material layer. The external fitting process is completed by thermally shrinking the tube so as to be in close contact with the foamed elastic layer by the method.
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 easily enters, and it is difficult to obtain uniformity of the film thickness and the dispersant.

Next, an extruder used in the present invention is shown in FIG.
This will be described below. 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.
While the air is being blown from the inside, an inner layer elastomer constituting a functional multilayer tube is formed from the first extruder 8 into the inner flow path 6, and a functional multilayer tube is formed from the second extruder 9 into the outer flow path 7. The inner layer 3 (i) and the outer layer 3 (o) are overlapped, integrated and extruded while inflating the inside of the functional multilayer tube 3 with air. The core metal 1 is cooled by a water cooling ring 10 provided on the outer periphery thereof, pulled by a tube feeder, and cut into a predetermined length in order to obtain a functional multi-layer tube 3 for a charging roller. Covering the foamed elastic layer 2 having In FIG. 3, reference numeral 22 denotes a timing pulley and reference numeral 23 denotes a feed belt.

Here, the gist of the technology of the present invention will be further described. When the temperature of the die 4 in the extruder of FIG. 3 is lowered, the viscosity of the tube material increases and the extrusion pressure increases. Thereby, it is considered that the composition under a high pressure, at the time of extrusion, expands at a stretch because the pressure is rapidly released at the extrusion port, and therefore, the dispersion of the conductive material in the resin composition proceeds, Even if more conductive material is added, a decrease in resistance is suppressed, and a desired resistance value can be obtained. It is known that, as the conductive material (carbon black) is uniformly dispersed in the composition, the resistance value is rather increased, canceling the usual tendency of the conductive material to increase in resistance to eliminate the resistance non-uniformity. Thus, since a large amount of the conductive material can be added, it is considered that the dispersion of the conductive material was effectively performed with respect to the amount that does not cause the resistance unevenness.

[0041]

The present invention will be described below in more detail with reference to more specific examples.

[When the Functional Multilayer Tube is Made of a Resistance Adjusting Layer / Conductivity Control Layer] The resistance adjusting layer may be made of a resin whose material itself has an appropriate resistance value, or mixed with carbon. A resin whose resistance value has been adjusted by using a resin may be used. A multilayer functional tube can be formed by simultaneously extruding each layer material of this example into a single layer. In the present invention, the tube is formed using a vertical extrusion device. In a horizontal extrusion device, the flow direction of the extruded tube is perpendicular to the gravity, so the effect of gravity acts in the circumferential direction of the tube, especially in the soft state immediately after being extruded. Therefore, it was considered that the electrophotographic use used in the present invention lacked in definition.

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

<Formation of foamed elastic layer>
A hose-shaped foamed elastic layer having an outer diameter of 11.5 mm [Ethylene-propylene-diene rubber (EPDM) is compounded with a vulcanizing agent and a foaming agent, and the mixture is formed into a hose shape by an extruder. Foamed in a vulcanizing can] with a length of 2
Cut into 25mm, the center hole, the above-mentioned diameter 5mm,
A core bar having a length of 260 mm was inserted.

(Example 1) <Formation of functional multilayer tube> As a material for the outer layer of the functional multilayer tube, a styrene-based resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass of polyethylene, 20 parts by mass of polyethylene, DBP oil absorption 300 to 500c
m ^3/100 g product name as carbon black: Ketjen Black EC (manufactured by Lion Akzo Co., Ltd.) 10 parts by mass (6.6 mass%) and DBP oil absorption of 150 cm ^3/10
As acidic carbon black having a pH of 0 g or less and a pH of 5 or less, 10 parts by mass (6.6 mass%) of Special Black 250 (manufactured by Degussa), 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate are V
Mix for several minutes in a mold blender. This was further melt-kneaded at 190 ° C. for 10 minutes using a pressure kneader. Furthermore,
After cooling, the mixture was pulverized by a pulverizer and pelletized by a single screw extruder.

As materials for the inner layer, 100 parts by mass of a polyurethane elastomer (melting point: 120 ° C.), 10 parts by mass (8.3% by mass) of Ketjen Black EC as carbon black, 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate Parts by mass were pelletized in the same process as the material of the outer layer.

Vertical extruder (Pla Giken's special order product,
These are combined with one crosshead by using FIG. 3).
Merge to form a multi-layer, die temperature 140 ° C, 160
The mixture was extruded into cold water 10 at a suitable temperature of 180 ° C., 180 ° C. and 200 ° C., further cooled and taken out (22 and 23). Thus, a functional multilayer tube having an inner diameter of about 11.1 mm was obtained.

(Example 2) <Formation of functional multilayer tube> As a material for the outer layer of the functional multilayer tube, a styrene resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass of JSR, melting point 100 ° C.), 20 parts by mass of polyethylene, trade name: Ketjen Black EC (manufactured by Lion Akzo) 2 as carbon black
0 parts by mass (11.4% by mass) and trade name: Specia
l Black 250 (manufactured by Degussa) 25 parts by mass (1
4.2% by mass), 10 parts by mass of magnesium oxide and 1 part by mass of calcium stearate were mixed for several minutes by a V-type blender. 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 of a polyurethane elastomer (melting point: 120 ° C.), 20 parts by mass (15.3% by mass) of Ketjen Black EC as carbon black, 10 parts by mass of magnesium oxide and 1 part by mass of calcium stearate The mass part was pelletized in the same step as the material of the outer layer, and a functional multilayer tube was obtained in the same step as in Example 1.

(Example 3) <Formation of functional multilayer tube> As a material of the outer layer of the functional multilayer tube, a styrene resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass (manufactured by JSR, melting point 100 ° C.), 20 parts by mass of polyethylene, 20 parts by mass (11.4% by mass) of Printex XE-2 (manufactured by Degussa) as carbon black, and Special B: Specialty B
rack 550 (manufactured by Degussa) 25 parts by mass (14.2
% By mass), 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate were mixed for several minutes by a V-type blender. This was further reduced to 10 ° C at 190 ° C using a pressure kneader.
Melted and kneaded for minutes. Furthermore, after cooling, it was pulverized by a pulverizer and pelletized by a single screw extruder.

[0051] As the material of the inner layer, 100 parts by weight of polyurethane elastomer (melting point 120 ° C.), trade name of carbon black: Ketjen Black EC 20 parts by (15.3 wt%), magnesium oxide 10 parts by weight and calcium stearate 1 the parts by weight, were pelleted by the same process as the material of the outer layer to obtain a functional multilayered tube by the same process as in example 1.

(Example 4) <Formation of functional multilayer tube> As a material of the outer layer of the functional multilayer tube, a styrene resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass of JSR, melting point 100 ° C.), 20 parts by mass of polyethylene, carbon black as trade name: Ketjen Black EC (Lion Akzo) 1
2 parts by mass (7.4% by mass) and trade name: Special
20 parts by mass of Black 250 (manufactured by Degussa) (1
2.3% by mass), 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate were mixed for several minutes by a V-type blender. 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 of a polyurethane elastomer (melting point: 120 ° C.), 16 parts by mass (10.9% by mass) of Ketjen Black EC as carbon black and Special Bl
20 parts by mass (13.6% by mass) of ack 250 (manufactured by Degussa), 10 parts by mass of magnesium oxide and 1 part by mass of calcium stearate were pelletized in the same step as the material of the outer layer, and the same step as in Example 1 was performed. To obtain a functional multi-layer tube.

(Comparative Example 1) <Formation of Functional Multi-layer Tube> As a material of the outer layer of the functional multi-layer tube, a styrene-based resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass of JSR Co., melting point 100 ° C.), 20 parts by mass of polyethylene, carbon black, trade name: Ketjen Black EC (manufactured by Lion Akzo) 5
Parts by mass (3.6% by mass) and trade name: Special
5 parts by mass (3.6% by mass) of Black 250 (manufactured by Degussa), 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate were 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.

100 parts by mass of a polyurethane elastomer (melting point: 120 ° C.) as a material of the inner layer, 5 parts by mass (4.3% by mass) of Ketjen Black EC as carbon black, 10 parts by mass of magnesium oxide and 1 part of calcium stearate The mass part was pelletized in the same step as the material of the outer layer, and a functional multilayer tube was obtained in the same step as in Example 1.

Comparative Example 2 <Formation of Functional Multilayer Tube> As a material for the outer layer of the functional multilayer tube, a styrene resin (styrene-ethylene / butylene-olefin copolymer resin, trade name: Dinalon, 100 parts by mass of JSR, melting point 100 ° C.), 20 parts by mass of polyethylene, trade name: Ketjen Black EC (manufactured by Lion Akzo) 2 as carbon black
5 parts by mass (13.5% by mass) and trade name: Specia
l Black 250 (manufactured by Degussa) 30 parts by mass (1
6.1 parts by mass), 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate were mixed for several minutes by a V-type blender. 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.

100 parts by mass of a polyurethane elastomer (melting point: 120 ° C.) as a material for the inner layer, 30 parts by mass (21.3% by mass) of Ketjen Black EC as carbon black, 10 parts by mass of magnesium oxide, and 1 part by mass of calcium stearate The mass part was pelletized in the same step as the material of the outer layer, and a functional multilayer tube was obtained in the same step as in Example 1.

<Heat treatment of functional multilayer tube> The obtained functional multilayer tube was subjected to a heat treatment at 100 ° C for 1 hour.

<Production of Roller> An inner diameter of 4.5 mm and an outer diameter of 1 in which a core metal having a diameter of 5 mm and a length of 260 mm was inserted into the center hole.
The above-mentioned functional multi-layer tube cut into a length of 230 mm in a hose-shaped foamed elastic layer having a length of 1.5 mm and a length of 225 mm is fitted around the outer periphery of the foamed elastic layer by a tube coating device (not shown), and is compacted. I wore it.

As a result of forming an image using this charging roller as a primary charger of an LBP (laser beam printer; Laser Jet 2-P manufactured by Hewlett-Packard Company), the functional multilayer tube 3 and the foamed elastic layer 2 were formed. A good image was obtained without any gaps between the layers and without wrinkling on the functional multi-layer tube 3 (Comparative Example 2).
As for (2), the surface of the tube was roughened during extrusion molding, and extrusion molding was not possible.) Table 1 shows an overview of the evaluation results.

[0061]

[Table 1]

^{[0062]-resistance: ○ 10 4 ~10 10 Ω ·} cm × 10 4 ~10 10 Ω · cm other than the volume resistivity value-image output: ○ good image △ slight image unevenness × image non-uniformity - resistance Does not fit and cannot determine image unevenness

FIG. 4 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having a charging roller according to the present invention.

In the figure, reference numeral 13 denotes an electrophotographic photosensitive member which is driven to rotate at a predetermined peripheral speed in the direction of the arrow. In the rotation process, the peripheral surface of the electrophotographic photoreceptor 13 is uniformly charged at a predetermined positive or negative potential by the charging roller 1 ′ of the present invention, and then exposed to light such as slit exposure or laser beam scanning exposure ( (Not shown). Thus an electrostatic latent image on the peripheral surface of the electrophotographic photosensitive member 13 are successively formed.

The formed electrostatic latent image is then transferred to developing means 1
5, and the developed toner image is
An electrophotographic photosensitive member 13 and a transfer unit 16
The electrophotographic photosensitive member 13 rotated and synchronized up to the transfer material 17 which is fed by a, are sequentially transferred by the transfer means 16 between the.

The transfer material 17 to which the image has been transferred is separated from the surface of the electrophotographic photoreceptor, introduced into the image fixing means 18 and subjected to image fixing to form an image formed product (copy / print).
Is printed out of the apparatus.

The surface of the electrophotographic photosensitive member 13 after the image transfer is
The transfer residual toner is removed by the cleaning unit 19 to be cleaned and is used for repeated image formation.

In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 13, charging member 1 ', developing means 15, and cleaning means 19 are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, the developing unit 15 and the cleaning unit 19 are integrally supported together with the electrophotographic photosensitive member 13 and the charging member 1 ′ to form a cartridge, and the process cartridge is detachably attached to the apparatus main body using a guide unit such as a rail 20 of the apparatus main body. 21
It can be.

When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 14 is reflected or transmitted from the original, or the original is read by a sensor and converted into a signal, and the exposure is performed according to this signal. Laser beam scanning,
The light is emitted by driving the LED array or driving the liquid crystal shutter array.

[0070] Thus, Examples 1-3 and Comparative Example 1,
Evaluation is performed by an image forming apparatus using a process cartridge in which the charging member 2 is incorporated.

[0071]

As described above, the charging roller of the present invention
By a method of lowering the molding temperature during extrusion, it is possible to obtain a designed resistance value despite the addition of a large amount of conductive material which usually causes a reduction in resistance, and a good image without defects such as image unevenness can be obtained. And other excellent properties.

[Brief description of the drawings]

1 is a vertical sectional front view of an example of a charging roller of the present invention.

FIG. 2 is a schematic vertical sectional front view of a vertical extruder corresponding to various multilayers of the functional multilayer tube used in the present invention.

FIG. 3 is a vertical sectional front view of an example of a vertical extruder for a functional multi-layer tube used in the present invention.

FIG. 4 is a schematic configuration diagram of an electrophotographic apparatus having a process cartridge having a charging roller of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core metal (metal layer) 1 'Charging roller 2 Foam elastic layer 3 Functional multilayer tube 3 (i) Inner layer 3 (o) Outer layer 4 Die 5 Central through hole 6, 7 Extrusion flow path 8 First extruder Reference Signs List 9 second extruder 10 water cooling ring 11 power supply 13 electrophotographic photoreceptor 14 image exposure light 15 developing means 16 transfer means 17 transfer material 18 image fixing means 19 cleaning means 20 rail 21 process cartridge 22 timing pulley (tube feed unit) 23 Feed belt (tube feed unit)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16C 13/00 F16C 13/00 BEZ // B29L 31:32 B29L 31:32 (72) Inventor Shishizuka Kazuyuki 1888-2 Kusazaki, Kusazaki-cho, Inashiki-gun, Ibaraki Prefecture (72) Inventor Toshihiro Otaka 1888-2 Kusazaki, Kusazaki-cho, Inashiki-gun, Ibaraki F-term (reference) 2H003 AA01 BB11 CC05 3J103 AA02 AA15 AA33 AA51 AA69 BA41 EA02 EA05 EA11 FA14 FA18 HA03 HA04 HA05 HA15 HA20 HA32 HA41 HA48 HA52 HA53 HA55 4F207 AA09 AA13 AA31 AA45 AB18 AD03 AD18 AG03 AG08 AH04 AR06 KA01 KA17 KB18 K18

Claims (4)

[Claims] 1. A method for manufacturing a charging roller using a functional multi-layer tube by vertical extrusion of a multi-layer simultaneous molding method having a tube extruding step, a tube cooling step, and a tube pulling step in a gravity direction. The amount of the conductive material in the composition of the outer layer component of the layer tube is 5% by mass to 2%.
8% by mass, the amount of the conductive material in the composition of the inner layer component is 5% by mass to 35% by mass, and the extrusion molding temperature (die temperature) when extruding the composition is 140 ° C.
A method for manufacturing a charging roller using a vertical extrusion tube, wherein the temperature is from 200 to 200 ° C. 2. The method for manufacturing a charging roller using a vertical extrusion tube according to claim 1, wherein the conductive material is carbon black. 3. The carbon black has a DBP oil absorption.
300-500cm ^Three/ 100g of carbon black
And DBP oil absorption 150cm^Three/ 100g or less and p
H is two kinds of acidic carbon blacks of 5 or less.
Item 3. Charging using the vertical extrusion tube according to item 1 or 2.
Roller manufacturing method. 4. The conductive elastic layer on the metal core, the functionality charging roller double layer is provided, the functional multilayer method of producing a charge roller according to any one of claims 1 to 3 a charging roller formed by.