JP2002311687A - Electrification roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrification roller having a surface layer and/or an intermediate layer having high uniformity of the resistance and little environmental dependence. SOLUTION: The electrification roller is used by bringing into contact with an image carrying body possessed by an electrophotographic device or an electrostatic recording device and is produced by applying the following ionic conductive tube on an elastic layer. The ionic conductive tube is made of a polymer composition containing (A) a polymer selected from a group consisting of polyurethane, polyamide and polyester thermoplastic elastomers and (B) a quaternary phosphonium salt having at least three phenyl groups coupled to phosphorus atoms in the molecule.

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 a main component of an electrophotographic apparatus, an electrostatic recording apparatus, and the like. The present invention relates to a charging roller having an intermediate layer.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus, an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric is brought into contact with the surface of the image carrier. A charging roller is used as a means for uniformly charging a body surface to a predetermined potential. The charging roller is a multilayer structure including a core provided at the center, a conductive elastic layer provided in a cylindrical shape around the core, and a surface layer provided on the outer periphery. It is also known to provide a plurality of thin layers such as an intermediate layer between the elastic layer and the surface layer.

The main role of the surface layer is to (1) improve the uniformity of the resistance in the axial and circumferential directions, and (2) improve the releasability of toner particles and paper powder to prevent sticking. . The main roles expected when the intermediate layer and the like are provided are (1) prevention of migration of oil and plasticizer from the elastic layer and the like to the surface layer, and (2) radial resistance for improving the function of the roller. Optimization of distribution, and (3) improvement of uniformity of axial and circumferential resistances.

[0004] Among the roles of the surface layer and the intermediate layer, it is particularly important to improve the uniformity of the resistance. The idea is that even if the conductive elastic layer is in a non-uniform conductive state, it is to be made uniform by the surface layer and the intermediate layer or the surface layer alone. In general, the elastic layer, the matrix polymer itself such as rubber or resin used for the surface layer and the intermediate layer is an insulator, in order to impart conductivity to these, usually carbon fine particles such as carbon black and graphite, Electron-conductive fine particles such as Sn-Sb-based and Zn-Al-based composite metal oxide fine particles are filled. In that case, no matter what dispersing means is used, it is inevitable that the dispersion state of the conductive fine particles in the polymer becomes microscopically nonuniform. As an example of such microscopic unevenness, formation of a network by agglomeration of carbon black is known. As a result of the non-uniform dispersion, a microscopic conductive path where a current easily flows locally is formed, the uniformity of the resistance is impaired, and the effect appears as a decrease in image quality.

On the other hand, as a means that can be expected to achieve more uniform dispersion or dissolution and therefore to improve the uniformity of resistance, electrolytes such as metal salts, quaternary ammonium salts, quaternary phosphonium salts, and metal complexes are used. Methods of imparting ionic conductivity by adding to a polymer have been studied (for example, Japanese Patent Application Laid-Open Nos.
-101652, JP-A-9-302232, JP-A-9-27215, JP-A-8-2209
No. 00 publication). In these methods, it is generally known that by imparting ionic conductivity, the hygroscopicity of the polymer is increased, and as a result, the humidity dependence of the resistance is increased, and thus the image quality is greatly affected by environmental conditions. A serious problem. Two factors can be considered as causes of the increase in the hygroscopicity. First, in order to exhibit ionic conductivity, the matrix polymer must have the ability to ionically dissociate the electrolyte, and must therefore contain polar groups densely. Such a polymer generally has a strong affinity for water and easily absorbs moisture. Second, the electrolyte itself generally has a strong affinity for water, is water-soluble, and sometimes exhibits deliquescence, so that the hygroscopicity of the ionic conductive polymer is further enhanced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a charging roller having a surface layer and / or an intermediate layer having high resistance uniformity and low environmental dependency. With the goal.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a charging roller used in contact with the surface of an image bearing member of an electrophotographic apparatus or an electrostatic recording apparatus. Ionic conductivity formed by a polymer selected from the group consisting of thermoplastic elastomers, and (B) a polymer composition containing a quaternary phosphonium salt having at least three phenyl groups bonded to a phosphorus atom in the molecule. The present invention provides a charging roller characterized in that a conductive tube is coated on an elastic layer.

[0008]

Next, the charging roller of the present invention will be described in detail for each constituent element.

<Quaternary Phosphonium Salts> Some electrolytes such as metal salts, quaternary ammonium salts, quaternary phosphonium salts, and metal complexes are dissolved in a matrix polymer having a polar group and are uniform at the molecular level. It is known that there is a compound that generates cations and generates carrier ions to express ionic conductivity. The resistance of such composites can be expected to be highly uniform.

On the other hand, the range of the volume resistivity required for the surface layer and the intermediate layer of the charging roller or the surface layer alone is usually 10 ⁶ to 10 ⁶ .
Although it is 10 ¹¹ Ω · cm, it is necessary to add a large amount of the above electrolyte in order to realize a resistance in this range. However, the electrolyte generally has a strong affinity for water, and the hygroscopicity (or water absorption rate) of the composite becomes higher than that of the matrix polymer, and therefore, the humidity dependence of resistance becomes strong. This is because an electrolyte having a low affinity for water is desired.

A major cause of the decrease in resistance due to the absorption of water by the ionic conductive polymer is that the strong coordination of water to ions increases the degree of dissociation of the electrolyte dissolved in the matrix polymer. It is presumed that the carrier ion concentration increases. If there is an electrolyte that can achieve low resistance with a small amount of addition, it means that the degree of dissociation in the matrix polymer is inherently sufficiently high. We can expect that the humidity dependence of resistance will be reduced.

Similarly, if there is an electrolyte having a low affinity for water, it means that the coordination ability of water is weak for the specific electrolyte, and the increase in the degree of dissociation due to moisture absorption is small. Therefore, it can be expected that the humidity dependency of the resistance will be small.

As a result of searching for many electrolytes, it was found that a quaternary phosphonium salt having at least three phenyl groups bonded to a phosphorus atom in a molecule can realize low resistance with a relatively small amount of addition, and has an affinity for water. Excellent electrolyte with unique properties, such as extremely low solubility, almost insoluble in water, and dissolution in polymers such as polyurethane, polyamide and polyester thermoplastic elastomers to form a uniform composite. They found something and completed the present invention. It is believed that the above specific properties are expressed by at least three phenyl groups in the molecule attached to the phosphorus atom. For example, even if a quaternary phosphonium salt having three long-chain alkyl groups such as tri (n-octyl) ethylphosphonium bromide is compared with that having a high affinity for water, such as dissolution in water, it is phenyl. The specific effect of the group is clear.

Further, it is generally known that quaternary phosphonium salts have high heat resistance and do not decompose at a temperature of about 300 ° C. or less. Therefore, a desired ionic conductive polymer composition can be produced by mixing a quaternary phosphonium salt with the above-mentioned various thermoplastic polymers by a melt-kneading method at a high temperature, and for the same reason, the polymer composition can be produced. Can be formed by a method requiring a high temperature such as an injection molding method or an extrusion molding method. As a result, the ionic conductive polymer composition can be manufactured at low cost and can be widely used. Needless to say, other processing methods such as dissolving the ion-conductive polymer composition in an organic solvent and using the composition as a coating material can also be employed.

The quaternary phosphonium salt having at least three phenyl groups bonded to a phosphorus atom used in the present invention includes, for example, a tetraphenylphosphonium salt, an ethyltriphenylphosphonium salt, a butyltriphenylphosphonium salt, a benzyltriphenylphosphonium salt. Phenylphosphonium salts and methyltriphenylphosphonium salts are preferred. Mixtures of two or more of these can also be used in the present invention. Among the above quaternary phosphonium salts, tetraphenylphosphonium salts are publicly known as existing chemical substances, and are particularly preferable because they have extremely low affinity for water. As the anion, a halogen anion such as bromine, chlorine and iodine, a boron tetrafluoride anion and a phosphorus hexafluoride anion are preferable.

The above-mentioned various quaternary phosphonium salts used in the present invention are white crystals having a melting point in the range of 206 to 315 ° C., but a temperature lower than the melting point, for example, 180 to 180 ° C., which is suitable for processing the thermoplastic elastomer. When mixed at 220 ° C. and melt-kneaded, the quaternary phosphonium salt dissolves in the thermoplastic elastomer to form a uniform composite, that is, the ionic conductive polymer composition.

In the present invention, 0.2 to 5 parts by weight of the above quaternary phosphonium salt is added to 100 parts by weight of a matrix polymer such as a polyurethane-based, polyamide-based, or polyester-based thermoplastic elastomer to obtain an ionic conductive material. Obtain a polymer composition. If the amount is less than 0.2 parts by mass, a sufficiently low resistance cannot be realized. If the amount is more than 5 parts by mass, a part of the quaternary phosphonium salt will not be dissolved in the matrix polymer, causing problems such as unevenness and blooming.

<Polymer> In the present invention, the polyurethane-based, polyamide-based, and polyester-based thermoplastic elastomers used as the matrix polymer for the ion-conductive polymer composition are each composed of a block comprising a hard segment and a soft segment. It is a copolymer. The soft segment is usually a polyether segment, and the hard segment is a polyurethane, polyamide or polyester segment, respectively. As described above, the three types of thermoplastic elastomers are common in that they include a polyether segment as a soft segment. Polyether is a polymer with an ether bond in the skeleton.It coordinates the ions necessary to dissolve and dissociate the electrolyte and generate carriers, and fast movement of the molecular chains to move the generated carriers quickly. That is, it has a relatively low glass transition point Tg. Such a property is required for developing ionic conductivity, and if an appropriate electrolyte is present, the ionic conductivity of the polymer as a whole including the hard segment can be developed. As the soft segment having such properties, a segment having an ester, a carbonate, an amine, a sulfide bond or the like in addition to the ether bond is known, and is suitable as a soft segment of the matrix polymer used in the present invention. However, ether bonds and carbonate bonds are superior in terms of chemical stability and mechanical properties.

The polyether polyol which is a starting material for producing the above polyether segment includes:
1,2 obtained by ring-opening polymerization of ethylene oxide, propylene oxide and higher epoxides and the like.
Polytetramethylene ether glycol (P) obtained by ring-opening polymerization of an epoxide polymer (PEG, PPG, etc.) and a cyclic ether such as tetrahydrofuran;
TMEG) and the like are preferable.

Specific examples of the above polymers include polyurethane thermoplastic elastomers Pandex (manufactured by Dainippon Ink and Chemicals, Inc.), Elastran (manufactured by Takeda Birdish Urethane Industries, Ltd.), milactran (manufactured by Nippon Milactran), Polyamide-based thermoplastic elastomers such as Desmopan (manufactured by Bayer), Chramylon (manufactured by Kuraray), Esten (manufactured by Kyowa Hakko Co., Ltd.) and Rezamin (manufactured by Dainichi Seika Kogyo Co., Ltd.) Nylon (manufactured by Ube Industries), Gleek (manufactured by Dainippon Ink and Chemicals), Pebax (manufactured by Toray Industries), and other polyester-based thermoplastic elastomers Hytrel (manufactured by Dupont Toray), Primaloy (manufactured by Mitsubishi Chemical) , Nuberan (manufactured by Teijin Limited), Gleek (Dainippon Ink and Chemicals, Inc.) ) And PELPRENE (manufactured by Toyobo Co., Ltd.), and the like.

<Charging Roller> The present invention relates to a charging roller used in contact with the surface of an image carrier of an electrophotographic apparatus or an electrostatic recording apparatus, wherein at least one of a surface layer and an intermediate layer is formed as an intermediate layer. When there is no layer, the charging roller formed by coating the surface layer with an ion-conductive tube produced by extruding the above-described ion-conductive polymer composition onto the elastic layer is provided. .

As described above, the intermediate layer and the surface layer formed on the conductive elastic layer have the respective roles as described above. However, there are cases where there is no intermediate layer and only the surface layer is provided. The ion-conductive tube formed from the ion-conductive polymer composition of the present invention can be used for one or both of the intermediate layer and the surface layer. Further, a tube made of an electron conductive polymer composition in which either the intermediate layer or the surface layer is filled with electron conductive fine particles can be used. The matrix polymer used for the intermediate layer and the surface layer is
Each may be the same or different. In the case of an electron conductive polymer composition filled with electron conductive fine particles, there is no particular restriction on the matrix polymer. The inside or outside of the ion conductive tube may be coated with a conductive paint.

<Tube> A conductive elastic layer provided in a cylindrical shape around a metal core provided at the center maintains a proper elasticity so that the nip width between the surface of the image bearing member and the charging roller is adjusted appropriately. It plays a role in ensuring charging uniformity. It is necessary to lower the hardness in order to maintain appropriate elasticity, and a method of forming an elastic layer with foamed rubber, a method of adding a softener such as an oil or a plasticizer to a rubber material for the elastic layer, and the like are known. ing. In the case of foamed rubber, the surface roughness of the elastic layer becomes extremely large, and when a softening agent is used, there arises a problem that they migrate and contaminate the surface of the image carrier. When the surface layer and / or the intermediate layer is formed by covering the elastic layer with a tube having a thickness of 50 to 500 μm, both of the above two problems are solved. That is,
A charging roller having a smooth surface and in which migration of the softener is prevented can be obtained.

The method for forming the ion conductive tube is preferably a blow molding method, an injection molding method or an extrusion molding method.
Extrusion molding is particularly preferred. Extrusion molding method
Pellets comprising the ionic conductive polymer composition were mixed with 18
This is a method of heating and melting at 0 to 220 ° C., continuously extruding from a die having a ring-shaped slit, and cooling and solidifying to form a tube. Extrusion is also advantageous in that it does not use organic solvents that can cause environmental problems.

The volume resistivity of the conductive tube is usually 10
^In the range of ⁶ to 10 ¹¹ Ω · cm, 10 ⁷ to 10 ¹⁰ Ω · c
The range of m is particularly preferred. When the range of 10 ⁶ to 10 ⁹ Ω · cm cannot be realized only by adding the quaternary phosphonium salt, electron conductive fine particles such as carbon black can be used in combination.

To cover the elastic layer with a tube,
A method is adopted in which air is blown into a tube to expand the outer diameter and insert a roller precursor composed of the core metal and an elastic layer provided around the core metal.

[0027]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but it should not be construed that the invention is limited thereto.

First, a roller precursor having a cylindrical conductive elastic layer on a metal core will be described. Metal core (SUS
An EPDM compound containing an appropriate amount of Ketjen black, a foaming agent, a foaming aid, a softening agent, a reinforcing agent, a vulcanizing agent, etc. was molded into a cylindrical shape on the outer peripheral surface of φ6 mm), and foamed and vulcanized by heating. . The shape was adjusted by polishing to obtain a roller precursor having a sponge-like conductive elastic layer having a thickness of 3 mm and a volume resistivity of 5 × 10 ⁴ Ω · cm. In the following Examples and Comparative Examples, a charging roller in which the outer peripheral surface of the roller precursor is covered with a surface layer and an intermediate layer or a surface layer alone will be described.

The roller resistance is determined by winding a 10 mm wide aluminum foil on a roller, applying a 250 V DC voltage between the core metal and the aluminum foil, and measuring the current to determine the resistance between the core metal and the aluminum foil. It was measured by calculating. The roller resistance was measured in each of the following environments.

Standard environment (N / N): 23 ° C., 55% RH High temperature and high humidity environment (H / H): 32.5 ° C., 80% RH Low temperature and low humidity environment (L / L): 15 ° C., 10% RH

In each of the above-mentioned environments, both humidity and temperature change, so that the humidity dependency cannot be separately evaluated. However, for the purpose of comparison between materials, there is no problem even if the difference in resistance behavior is mainly attributed to the difference in humidity dependence, since the temperature range is relatively small.

The water absorption was used as an index indicating the hygroscopicity of the surface layer and the intermediate layer. The water absorption was measured using a 200 μm or 150 μm thick tube molded by extrusion.
It was immersed in water of 20 ° C. for 20 hours, and the change in weight was measured to calculate.

The evaluation of the microscopic uniformity of the resistance of the conductive roller was performed by evaluating the initial output image when the conductive roller was mounted on an electrophotographic printer cartridge and only a DC voltage of 1.1 kV was applied. The determination was made by visually determining the uniformity.

The volume resistivity of the tube was measured using an insulation resistance meter in the above N / N environment.

(Example 1) Polyurethane thermoplastic elastomer (Milactran E38 manufactured by Nippon Miractran Co., Ltd.)
5) To 100 parts by mass, 3 parts by mass of tetraphenylphosphonium bromide (manufactured by Hokko Chemical Industry Co., Ltd., TPP-PB) and an additive such as a lubricant were blended, and the mixture was melt-kneaded at 200 ° C. for 10 minutes by a pressure kneader, An ionic conductive polymer composition was obtained. The obtained ionic conductive polymer composition was formed into a seamless tube having an inner diameter of 10 mm, a thickness of 200 μm, and a length of 250 mm by an extruder. The volume resistivity of the tube was 4.0 × 10 ⁷ Ω · cm, and the water absorption was 1.2% by mass. Air was blown into the seamless tube, and the roller precursor was inserted while widening the outer diameter, to obtain a charging roller intermediate in which the elastic layer was covered with the tubular ion-conductive intermediate layer.

Next, an appropriate amount of Ketjen black and other additives were blended with a hydrogenated SBS-based thermoplastic elastomer (Lavalon SE8400, manufactured by Mitsubishi Chemical Corporation) and melt-kneaded at 200 ° C. for 10 minutes using a pressure kneader. An electron conductive polymer composition was obtained. The obtained electron conductive polymer composition was extruded with an extruder to an inner diameter of 10.5 mm and a thickness of 150.
It was formed into a seamless tube having a length of 250 μm and a length of 250 μm. The volume resistivity of the tube is 3.7 × 10 ⁸ Ω · cm,
The water absorption was 1.0% by mass. The elastic layer is covered with the tubular ion-conductive intermediate layer and the tubular electron-conductive surface layer by blowing air into the seamless tube and inserting the charging roller intermediate covered with the intermediate layer while expanding its outer diameter. The obtained charging roller was obtained. Excess tubes at both ends were cut off to complete the charging roller of the present invention.

Example 2 Polyamide Thermoplastic Elastomer (Pebax 4033SN01, manufactured by Toray Industries, Inc.) 10
0 parts by mass of 1 part by mass of ethyltriphenylphosphonium tetrafluoroborate (manufactured by Nippon Chemical Industry Co., Ltd.) and an additive such as a lubricant were blended, and 2 parts were added by a pressure kneader.
The mixture was melt-kneaded at 00 ° C. for 10 minutes to obtain an ion-conductive polymer composition. The obtained ion-conductive polymer composition was extruded by an extruder to an inner diameter of 10 mm, a thickness of 150 μm, and a length of 25 μm.
It was molded into a 0 mm seamless tube. The volume resistivity of the tube was 2.2 × 10 ⁸ Ω · cm, and the water absorption was 0.7% by mass. Air was blown into the seamless tube, and the roller precursor was inserted while widening the outer diameter, thereby obtaining a charging roller having an elastic layer covered with a tubular ion-conductive surface layer. Excess tubes at both ends were cut off to complete the charging roller of the present invention.

Example 3 Polyester thermoplastic elastomer (Perprene P55B, manufactured by Toyobo Co., Ltd.) 100
3 parts by mass of tetraphenylphosphonium bromide (manufactured by Hokko Chemical Industry Co., Ltd., TPP-PB) and an additive such as a lubricant were blended with the parts by mass, and 220 parts were mixed by a pressure kneader.
The mixture was melted and kneaded at 10 ° C. for 10 minutes to obtain an ionic conductive polymer composition. The obtained ionic conductive polymer composition was extruded by an extruder to an inner diameter of 10 mm, a thickness of 200 μm, and a length of 250 m.
m seamless tube. The volume resistivity of the tube is 3.3 × 10 ⁷ Ω · cm, and the water absorption is 1.1% by mass.
Met. Blow air into the seamless tube,
By inserting the roller precursor while expanding its outer diameter, a charging roller intermediate in which the elastic layer was covered with the tubular ion-conductive intermediate layer was obtained.

Next, the same tube as that used in Example 2 was coated on the intermediate charging roller covered with the above-mentioned intermediate layer, so that the elastic layer was formed into a tubular ion-conductive intermediate layer and a tubular ion-conductive intermediate layer. Thus, a charging roller covered with the surface layer was obtained. Excess tubes at both ends were cut off to complete the charging roller of the present invention.

(Comparative Example 1) Polyurethane thermoplastic elastomer (Milactran E38, manufactured by Nippon Milactran Co., Ltd.)
5) An appropriate amount of Ketjen Black and other additives were blended, and the mixture was melt-kneaded at 200 ° C. for 10 minutes using a pressure kneader to obtain an electron conductive polymer composition. The obtained electron conductive polymer composition was extruded by an extruder to an inner diameter of 10 m.
m, a seamless tube having a thickness of 200 μm and a length of 250 mm. The volume resistivity of the tube is 4.5 × 10
⁷ Ω · cm, and the water absorption was 2.6% by mass. Air was blown into the seamless tube, and the roller precursor was inserted while expanding the outer diameter of the seamless tube to obtain a charging roller intermediate in which the elastic layer was covered with the tubular electron conductive intermediate layer.

Then, the same tube as that used in the surface layer of Example 1 was coated on the charging roller intermediate covered with the above-mentioned intermediate layer, so that the elastic layer was formed into a tube-shaped electron conductive intermediate layer and a tube-shaped intermediate layer. A charging roller covered with an electron conductive surface layer was obtained. Excess tubes at both ends were cut off to complete the charging roller.

Comparative Example 2 A quaternary phosphonium salt having three long-chain alkyl groups instead of phenyl groups per 100 parts by mass of a polyurethane thermoplastic elastomer (Milactran E385 manufactured by Nippon Miractran Co.) as an intermediate layer , Tri (n-octyl) ethylphosphonium bromide (manufactured by Nippon Chemical Industry Co., Ltd., Hishicolin PX-82)
B) An ionic conductive polymer composition was obtained in the same manner as in Example 1 except that 3 parts by mass was added. The obtained ion-conductive polymer composition was formed into a seamless tube in the same manner as in Example 1. The volume resistivity of the tube is 6.8 × 1
0 ⁷ Ω · cm and the water absorption was 8.3% by mass. By inserting the roller precursor, a charging roller intermediate in which the elastic layer was covered with the tubular ion-conductive intermediate layer was obtained.

Then, the same tube as that used in the surface layer of Example 1 was coated on the conductive roller intermediate body covered with the above-mentioned intermediate layer, so that the elastic layer became a tubular ion-conductive intermediate layer and a tube. To obtain a charging roller coated with the electron conductive surface layer. Excess tubes at both ends were cut off to complete the charging roller.

Comparative Example 3 A quaternary phosphonium salt having three long-chain alkyl groups in place of the phenyl group, tri (n-
A charging roller having an elastic layer covered with a tubular ion-conductive surface layer was prepared in the same manner as in Example 2 except that 1 part by mass of (octyl) ethylphosphonium bromide (Nippon Chemical Industrial Co., Ltd., Hishicolin PX-82B) was added. Obtained. The volume resistivity of the tube is 3.5 × 10 ⁸ Ω · cm,
The water absorption was 6.9% by mass.

For the charging rollers manufactured in the above Examples and Comparative Examples, the measurement of the roller resistance in each environment and the evaluation of the microscopic uniformity of the resistance were performed by the above-described methods. Table 1 shows the results.

[0046]

[Table 1]

Table 1 shows the following. That is, the quaternary phosphonium salt having at least three phenyl groups in the molecule used in the ion conductive polymer composition is a quaternary phosphonium salt having at least three long-chain alkyl groups in the molecule. In comparison, the affinity for water is remarkably low, so that the resulting conductive polymer composition has less resistance to the environment (or humidity). In addition, compared to a conductive polymer composition filled with electron conductive fine particles such as carbon black, the microscopic uniformity of resistance is high, and the degree of environmental dependence is equal or higher.

Further, when an ion conductive tube obtained by extrusion-molding the ion conductive polymer composition of the present invention is used for the intermediate layer, the surface layer is an electron conductive tube using carbon black. However, it was found that the microscopic uniformity of the resistance was improved.

[0049]

As described above, the present invention relates to a charging roller which is used in contact with the surface of an image carrier of an electrophotographic apparatus or an electrostatic recording apparatus.
A polymer selected from the group consisting of polyamide-based and polyester-based thermoplastic elastomers, and (B) a polymer composition containing a quaternary phosphonium salt having at least three phenyl groups bonded to a phosphorus atom in the molecule. An object of the present invention is to provide a charging roller characterized in that the formed ion conductive tube is coated on an elastic layer. A charging roller having excellent resistance uniformity and having little humidity dependency of resistance can be obtained.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H200 HB12 HB43 HB45 HB46 HB47 LC02 LC09 LC10 MA02 MA08 MA11 MA12 MA14 MA17 MA20 MB04 MC20 3J103 AA02 BA41 GA02 GA52 GA57 GA58 GA60 HA04 HA20 HA46 HA48

Claims (4)

[Claims] 1. A charging roller used in contact with an image carrier surface of an electrophotographic apparatus or an electrostatic recording apparatus, wherein the charging roller is selected from the group consisting of (A) a polyurethane-based, polyamide-based, and polyester-based thermoplastic elastomer. An ion-conductive tube formed of a polymer composition containing the polymer obtained and (B) a quaternary phosphonium salt having at least three phenyl groups bonded to a phosphorus atom in the molecule, on the elastic layer. A charging roller characterized by being coated. 2. The charging roller according to claim 1, wherein the quaternary phosphonium salt is tetraphenylphosphonium bromide. 3. The charging roller according to claim 1, wherein the quaternary phosphonium salt is ethyltriphenylphosphonium tetrafluoroborate. 4. The polymer 1 having a quaternary phosphonium salt content of
The amount is 0.2 to 5 parts by mass relative to 00 parts by mass.
4. The charging roller according to any one of 3.