JP5106009B2 - Conductive member for electrophotographic apparatus - Google Patents

Description

  The present invention relates to a conductive member for an electrophotographic apparatus used for a developing member, a charging member, a transfer member and the like of an electrophotographic apparatus.

  Conventionally, various methods are known as electrophotographic methods. As a general example, a uniform potential is applied to the surface of a photoreceptor using a photosensitive (photoconductive) substance (charging process), and the surface of the photoreceptor is partially exposed to form an electrical latent image. (Exposure process) The latent image is made visible with toner (development process), and the toner is transferred to a transfer material such as paper (transfer process). Thereafter, there is a method in which the toner is fixed on the transfer material by heat, pressure or the like (fixing step) to obtain an image. Further, an additional process such as removal of toner particles not transferred onto the transfer material but remaining on the photoconductor from the photoconductor by various means (cleaning process) may be added.

  In such an electrophotographic apparatus, various conductive members for an electrophotographic apparatus are used in the form of a roller, a blade, a brush, a belt, a film, a sheet, a chip, and the like in processes such as charging, development, and transfer. .

In order to be suitably used as a conductive member for an electrophotographic apparatus, a conductive polymer material having a semiconductive region of about 10 ⁴ to 10 ¹¹ Ωcm is required. The conductive development mechanism of the conductive polymer material is roughly classified into an ion conductive mechanism and an electronic conductive mechanism. Among them, a conductive polymer material based on an electronic conduction mechanism is obtained by dispersing and mixing conductive particles such as carbon black, carbon fiber, graphite, metal fine powder, and metal oxide in a matrix polymer. Compared to ion conductive polymer materials, electronic conductive polymer materials have advantages such as low resistance to temperature and humidity, low cost, and few bleeds and blooms. Therefore, the electroconductive member for electrophotographic apparatus using the electroconductive polymer material is less likely to fluctuate the image due to the use environment such as temperature and humidity, and hardly contaminates the photoconductor. Is preferred. However, it is very difficult to control the conductivity in the vicinity of the percolation threshold where the conductivity of the electron conductive polymer material changes rapidly with respect to the filling amount of the conductive particles. Therefore, in a conductive member for an electrophotographic apparatus that requires conductivity near the percolation threshold, there is a large variation in electric resistance within the member and between lots, and it is difficult to control the electric resistance. ing.

Conventionally, various devices have been devised in order to obtain a semiconductive electroconductive polymer material with small variation. As one of them, a method of using a quaternary ammonium salt and carbon black in combination (Patent Document 1) has been reported. However, the quaternary ammonium salt tends to ooze out on the surface of the molded article containing it, so-called bleeding. As a result, an image defect may be caused (Patent Documents 2 and 3).
JP 2000-17118 A JP-A-2005-350621 JP 2003-223038 A

  An object of the present invention is to provide a conductive member for an electrophotographic apparatus using a quaternary ammonium salt, which has appropriate conductivity and can suppress the occurrence of image defects due to bleeding of the quaternary ammonium salt. An object is to provide a conductive member for an electrophotographic apparatus.

The present invention provides a conductive elastic body comprising a matrix polymer (A), electron conductive conductive particles (B) and a quaternary ammonium salt (C) having a number average molecular weight of 1000 or more on a conductive support. An electroconductive member for an electrophotographic apparatus, wherein the quaternary ammonium salt (C) has a polyalkenyloxy group .

  The electroconductive member for an electrophotographic apparatus of the present invention has moderate conductivity, and even when a quaternary ammonium salt is used, it is possible to suppress the occurrence of image defects due to bleeding of the quaternary ammonium salt. .

The electroconductive member for an electrophotographic apparatus of the present invention has a matrix polymer (A), electroconductive electroconductive particles (hereinafter also simply referred to as “electroconductive particles”) (B) and a number on an electroconductive support. A conductive member for an electrophotographic apparatus having a conductive elastic body containing a quaternary ammonium salt (C) having an average molecular weight of 1000 or more , wherein the quaternary ammonium salt (C) has a polyalkenyloxy group. It is characterized by that.

  The conductive support in the conductive member for an electrophotographic apparatus of the present invention is conductive and has a strength capable of supporting a conductive elastic body provided on the conductive support. The shape of the member is specified. As the shape, if the electroconductive member for an electrophotographic apparatus is in the form of a roller, a columnar shape, a cylindrical shape or the like is preferable. For example, a member having an outer diameter of 6 mm or the like can be exemplified. As the material, metal materials such as iron, copper, stainless steel, aluminum and nickel can be used, and plating is performed for the purpose of imparting rust prevention and scratch resistance to the extent that these metals do not lose good conductivity. It may have been processed. In addition, an adhesive having a thickness of 1 μm or more and 20 μm or less can be applied and used for the purpose of adhesion to the conductive elastic body provided thereon as long as the conductivity is not impaired.

  The conductive elastic body of the present invention contains a matrix polymer (A), conductive particles (B), and a quaternary ammonium salt (C) having a number average molecular weight of 1000 or more.

The matrix polymer (A) is a polymer such as a resin or rubber capable of dispersing the conductive particles (B) and the quaternary ammonium salt (C). In the case where the electroconductive member for electrophotographic apparatus of the present invention is a member that is used while being in contact with another member, it is preferable to impart elasticity that does not cause image defects to the electroconductive elastic body. Examples of elasticity that does not cause image defects include the following degrees.
(1) Elasticity within a range that does not scrape the surface of a contacted member such as a photoreceptor to which the conductive member for an electrophotographic apparatus of the present invention comes into contact. (2) Elasticity within a range in which the toner and the external additive contained in the toner are not attached as dirt by being pressed onto the surface of the electroconductive member for electrophotographic apparatus or the contacted member of the present invention. (3) When the electroconductive member for an electrophotographic apparatus of the present invention is in the form of a roller, the elasticity is in the range where the member does not rotate and stick-slip with respect to the rotation of the contacted member. (4) Elasticity within a range having an appropriate nip between the contacted member such as discharge and toner sending / receiving and the electrophotographic conductive member of the present invention.

  Further, the matrix polymer (A) preferably has a high viscosity and a high polarity because the dispersion state of the conductive particles (B) tends to be good. When the dispersibility of the conductive particles (B) in the matrix polymer (A) is excessive, the use of the conductive particles (B) can be increased in order to impart an appropriate resistance to the mixture. The amount of the particles (B) used is preferably in a range where the conductive elastic body does not have high hardness.

  As said matrix polymer (A), what has rubber | gum, a thermoplastic elastomer, or these combination as a main component is preferable. Specific examples of rubber include the following. Polyurethane rubber, silicone rubber, butadiene rubber, isoprene rubber, chloroprene rubber. Styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber and the like. Examples of thermoplastic elastomers include styrene elastomers and olefin elastomers. These rubbers and elastomers can be used alone or in combination of two or more.

  Among these, acrylonitrile butadiene rubber is particularly preferable because it has moderate polarity and elasticity and has a very high effect of suppressing bleeding of the quaternary ammonium salt (C). This is presumably because the acrylonitrile butadiene rubber has good compatibility with the quaternary ammonium salt (C) having a number average molecular weight of 1000 or more, and its molecular mobility is relatively small.

  Here, bleed means that when a pressure is applied to the electroconductive member for electrophotographic apparatus of the present invention, the liquid or powdery compounding agent in the electroconductive elastic body moves, compared with the inside of the electroconductive elastic body. A phenomenon in which a compounding agent is present at a high concentration on the surface.

  The conductive particles (B) are those that transport charges in the matrix polymer by transferring electrons between the conductive particles, that is, electronically conductive particles.

  Examples of the conductive particles (B) include the following. Conductive carbon such as ketjen black EC and acetylene black. Carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT. Oxidized color (ink) carbon, pyrolytic carbon, natural graphite, artificial graphite. Metals such as tin oxide, titanium oxide, zinc oxide, copper, silver, and metal oxides.

  Among these, carbon black is particularly preferable because it has a high effect of suppressing bleeding of the quaternary ammonium salt (C) having a number average molecular weight of 1000 or more. Although this detailed mechanism is unknown, it is presumed that carbon black restrains the quaternary ammonium salt having a number average molecular weight of 1000 or more and suppresses the migration thereof. Carbon black having a DBP oil absorption of 50 ml / 100 g or more and 500 ml / 100 g or less is preferred because it is easy to adjust the semiconductive electrical resistance of the conductive elastic body. Here, the measured value obtained by the measuring method based on JISK6217: 1997 can be employ | adopted for DBP oil absorption.

  The quaternary ammonium salt (C) may be any as long as the number average molecular weight is 1000 or more, but is preferably 50000 or less.

  Here, the value measured by gel permeation chromatography (GPC) can be adopted as the number average molecular weight of the quaternary ammonium salt.

  As said quaternary ammonium salt (C), the quaternary ammonium salt shown by Formula (1) is preferable.

In formula (1), two or three of R _{1 to} R ₄ represent an alkyl group having 1 to 4 carbon atoms or a benzyl group, and the remaining one or two are represented by formula (1). that a quaternary number average molecular weight of the ammonium salt (C) to display the organic group having a molecular weight of 1000 or more, as such organic group, polyalkenyl group satisfying the molecular weight _{(- (RO) n -:} R it is an alkenyl group). In the formula (1), X preferably represents a halogen atom, ClO ₄ ⁻ , BF ₄ ⁻ , HSO ₄ ⁻ , CH ₃ SO ₄ ⁻ or C ₂ H ₅ SO ₄ ^— .

  Furthermore, the quaternary ammonium salt (C) is preferably a quaternary ammonium salt having a polyalkenyloxy group represented by the formula (2).

In the formula, n may be any as long as it represents an integer of 15 or more, but is preferably 1000 or less. The ammonium salt represented by the formula (2) is preferable because the fluidity of the composition during molding of the conductive elastic body is increased and the molding processability is improved. As the quaternary ammonium salt having a polyalkenyloxy group represented by the formula (2), commercially available ones may be applied. For example, Adekacol CC-15, CC-36, CC-42 (Asahi) Denka Kogyo Co., Ltd.) can be exemplified.

  The quaternary ammonium salt (C) plays a role of improving the dispersion of the conductive particles (B) in the conductive elastic body. As a phenomenon representing it, the quaternary ammonium salt (C) has a higher electrical resistance when it is used than when it is not used in the conductive elastic body, and variation in resistance is also reduced. There is. This is presumed to be because the polar group portion of the quaternary ammonium salt (C) interacts with the conductive particles to separate the aggregates of the conductive particles. That is, it can be said that the quaternary ammonium salt (C) does not bleed because it does not exhibit conductivity by electrophoresis like a general quaternary ammonium salt.

The content of the conductive particles (B) and the quaternary ammonium salt (C) imparts conductivity to the conductive elastic body thereby, so that the conductive elastic body has a desired electrical resistance, for example, 10 ³ Ωcm. It is preferable to adjust so that it may become -10 < ⁷ > ohm-cm. It is preferable that content of electroconductive particle (B) is the range of 20 to 80 mass parts with respect to 100 mass parts of said matrix polymers (A). If content of electroconductive particle (B) is 20 mass parts or more, the dispersion | variation in the electrical resistance which arises in an electroconductive elastic body can be suppressed, and if it is 80 mass parts or less, an electroconductive elastic body is high hardness. It can suppress that it becomes, and it can suppress that moldability falls. The content of the quaternary ammonium salt (C) is preferably in the range of 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the matrix polymer (A). If the content of the quaternary ammonium salt is 0.1 parts by mass or more, variation in electric resistance generated in the conductive elastic body can be suppressed, and if it is 3.0 parts by mass or less, the conductive elastic body. It is possible to suppress a decrease in mechanical properties of the material and to suppress bleeding.

  The said conductive elastic body may contain the compounding agent in the range which does not inhibit these functions other than the said substance. As such a compounding agent, a processing aid, a crosslinking agent, a crosslinking accelerator, a crosslinking acceleration aid, a crosslinking retarder, a filler, a dispersant, a foaming agent, a lubricant, an antiaging agent, an ozone deterioration preventing agent, an antioxidant, Examples thereof include a conductive agent.

  It is preferable to add the compounding agent involved in crosslinking in an amount capable of forming appropriate crosslinking in the matrix polymer. Forms crosslinks in the matrix polymer to the extent that the conductive elastic body does not become high hardness, suppresses excessive molecular movement of the matrix polymer, suppresses bleeding of the compounding agent, and excessive crosslinks remaining in the matrix polymer It is preferable to suppress bleeding such as an agent.

  As a method for producing the conductive elastic body, an uncured composition is prepared by mixing matrix polymer (A), conductive particles (B), quaternary ammonium salt (C), and other necessary compounding agents. For mixing, a closed kneader such as a Banbury mixer, an intermix or a pressure kneader, or an open kneader such as an open roll can be used. The molding method of the obtained uncured composition may be any method such as extrusion molding or molding, but a method of extruding onto the conductive support and extrusion molding integrally with the conductive support is preferable. .

  For the extrusion molding of the uncured composition, for example, a roller extrusion molding apparatus shown in the schematic configuration diagram of FIG. 1 can be used. The roller extrusion molding apparatus shown in FIG. 1 includes a cross head 21, a support transport roller 22 that transports a conductive support 23 to the cross head, and an extrusion screw 24 that supplies the kneaded material by extrusion molding through a die. And are connected. In the cross head, the conductive support conveyed to the cross head is inserted and integrated into a cylindrical extruded product supplied from an extrusion screw from a direction perpendicular thereto, and the end is cut and removed 25. An uncured rubber roller 26 is produced.

  Thereafter, the uncured rubber roller is cured. Examples of the curing method include molding curing, vulcanization can curing, actinic ray irradiation curing, induction heating curing, and continuous curing.

  After the rubber is cured, it is preferable that the conductive elastic body is ground with a grindstone in order to obtain a desired shape and surface roughness. As a method for grinding the conductive elastic body, a traverse grinding method for moving a short grinding wheel, a wide grinding method using a grinding wheel having a width wider than the length of the roller, etc. can be selected. A wide grinding system that can be ground with is more preferable.

  The electroconductive member for an electrophotographic apparatus of the present invention may be any as long as it has the above conductive elastic body, but may have a surface layer on the conductive elastic body.

  The surface layer is preferably one having low adhesion to contaminants such as toner, external additives, and paper dust. Examples of the binder resin for the surface layer include silicone-based, fluorine-based, urethane-based, acrylic-based, urethane-modified acrylic-based, and silicone-modified urethane-based. Among these, those mainly composed of polysiloxane having a fluorinated alkyl group and an alkenyloxy group (-RO-: R represents an alkenyl group) are preferable. By using such polysiloxane as a main component, adhesion of dirt such as toner can be remarkably suppressed and a surface layer can be easily formed.

  The surface layer may contain a conductive agent, a filler, a leveling agent, a dispersant, resin particles, a lubricant, a crosslinking agent, an antioxidant, and the like that can be dispersed in these binder resins.

  As a method for forming such a surface layer, any method such as extrusion molding, cast molding, and coating molding may be used. However, in the case of the surface layer containing polysiloxane as a main component, coating molding is preferable. As a coating method of the prepared coating liquid, any method such as coating, dipping, spraying, ring coating (Japanese Patent Laid-Open No. 2005-321749) may be used.

  The molding coating solution used for the preparation of the surface layer containing polysiloxane as a main component includes a hydrolyzable silane compound having a fluoroalkyl group, a hydrolyzable silane compound having an epoxy group, and a cationic polymerizable catalyst. An organic-inorganic hybrid sol can be suitably used. The organic-inorganic hybrid sol is a sol state of an organic-inorganic hybrid material produced by a so-called sol-gel method, and can be prepared by condensing a mixture of hydrolyzable silane compounds having an epoxy group by hydrolysis. A cationic polymerizable catalyst is added to this organic-inorganic hybrid sol to form a coating solution. After coating, the coating film is irradiated with an actinic ray such as ultraviolet rays to cleave the epoxy group to form a cross-link. A surface layer of a gel film can be formed.

  High-power low-pressure mercury lamps, electrodeless low-pressure mercury lamps, excimer lamps, high-pressure mercury lamps, metal halide lamps, etc. can be used for the above-mentioned ultraviolet irradiation. Most suitable. High-power low-pressure mercury lamps and electrodeless low-pressure mercury lamps include, for example, those in which a titanium oxide film or silica film is formed on the inner and outer surfaces of a quartz glass tube or the like containing discharge gas or mercury, etc. The ones made are preferred. In a lamp made of such a material, the wavelength of 200 nm or less is cut, and the intensity of ultraviolet rays typified by the wavelength of 254 nm is preferably 60% or more of the total wavelength intensity.

  On the other hand, the ultraviolet rays from the excimer lamp have a peak at a short wavelength of 172 nm that generates ozone, and there are almost no other peaks, and the surface of the conductive elastic body tends to be oxidized by the generated ozone. As a result, the surface of the electrophotographic apparatus conductive member has a reduced contact angle with water, which causes adhesion of toner and the like. In addition, ultraviolet rays from high-pressure mercury lamps and metal halide lamps have a wavelength of 365 nm, which may generate heat and may cause deterioration of the resin and rubber. Also, since the wavelength is relatively long, the irradiation time is long and efficient. Tend to decrease.

Gelation of the organic-inorganic hybrid film by irradiation with ultraviolet rays can be adjusted by the cumulative amount of ultraviolet rays calculated by the following formula and the irradiation distance of ultraviolet rays. As the integrated quantity of ultraviolet light required for gelation, for example, mention may be made of ^{1000mJ / cm 2 ~100000mJ / cm 2} .

UV integrated light quantity (mJ / cm ² ) = UV intensity (mW / cm ² ) × irradiation time (sec)
The surface layer thus obtained preferably has an average film thickness of 5 nm to 1000 nm. If the film thickness is in the above range, the surface layer has flexibility to follow the deformation of the underlying conductive elastic body, wear resistance, and does not affect the electrical characteristics of the conductive elastic body, The electrical characteristics of the conductive elastic body can be maintained.

  As an example of the conductive member for an electrophotographic apparatus of the present invention, as shown in FIG. 2, a conductive elastic layer 12 and a surface layer 13 which are conductive elastic bodies are sequentially formed on the outer periphery of a conductive support (shaft) 11. The electroconductive roller for electrophotographic apparatuses provided can be mentioned. In this conductive roller, the conductive support has a columnar shape with a diameter of 6 mm, the conductive elastic layer has a thickness of 1.25 mm, and the surface layer has a thickness of 20 nm.

  The electroconductive member for an electrophotographic apparatus of the present invention is applied in various forms such as a roller, a blade, a brush, a belt, a film, a sheet, and a chip used in processes such as charging, development, and transfer, and has excellent conductivity. The blade can be suppressed despite having the property.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, the technical scope of this invention is not limited to the following.
[Example 1]
The following materials were kneaded with a pressure kneader for 15 minutes.
Acrylonitrile-butadiene rubber (NBR) (N230SV: JSR (Ltd.)) 100 parts by weight of carbon black (Toka Black # 7360SB: manufactured by Tokai Carbon Co., Ltd.) 52 parts by weight (DBP oil absorption of 87cm ^3/100 g)
Zinc stearate 1 part by mass Zinc oxide 5 parts by mass Calcium carbonate (Nanox # 30: manufactured by Maruo Calcium Co., Ltd.) 20 parts by mass liquid epoxidized polybutadiene (Adekaizer BF-1000: manufactured by Asahi Denka Kogyo Co., Ltd.) 10 parts by mass Quaternary ammonium salt (Adeka Coal CC-42: manufactured by Asahi Denka Kogyo Co., Ltd.) 1 part by mass Further, the following substances were added and kneaded with an open roll for 15 minutes to obtain a kneaded product.
Dibenzothiazolyl disulfide (Noxeller DM-P: Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass Tetrabenzylthiuram disulfide (Noxeller TBzTD: Ouchi Shinsei Chemical Co., Ltd.) 3 parts by mass Sulfur 1.2 parts by mass Liquid Since epoxidized polybutadiene is liquid, it has good fluidity in an uncrosslinked state and brings about the same effect as a plasticizer. It can be cured after crosslinking to lower the molecular mobility of the conductive elastic layer and suppress bleeding. be able to.

  The number average molecular weight Mn of the quaternary ammonium salt used was measured by GPC using a gel column based on styrenedivinylbenzene, and found to be 3391 when polypropylene glycol was determined as a calibration curve.

  A thermosetting adhesive (Metallock N-33: manufactured by Toyo Chemical Co., Ltd.) is applied to the axially central portion 231 mm of the cylindrical surface of a cylindrical conductive support (nickel plating) having a diameter of 6 mm and a length of 256 mm. It dried for 10 minutes at 150 degreeC, the adhesive agent was made into the semi-hardened state, and the electroconductive support body was prepared.

  Using the kneaded product and the conductive support, the kneaded product was extruded into a cylindrical shape simultaneously with the conductive support using the roller extrusion molding apparatus shown in FIG. 1 to obtain an uncured rubber roller. The conductive elastic layer is left in the axially central portion of 232 mm, both ends thereof are cut and removed, and this uncured rubber roller is placed in a hot air oven and heated at 160 ° C. for 1 hour to be cured to form a conductive elastic body. Thus, a cylindrical cured rubber roller having a diameter of 8.7 mm was obtained.

  This cured rubber roller is ground with a wide grinding machine (LNC-600-F4L-BME, a CNC grinding machine dedicated to rubber rolls) and made into a crown shape with an end diameter of 8.3 mm and a center part of 8.5 mm. Molded.

Subsequently, in order to form a surface layer, the following substances were mixed, stirred at room temperature, and then heated to reflux for 24 hours to prepare an organic-inorganic hybrid sol.
Glycidoxypropyltriethoxysilane (GPTES) 27.84 g (0.1 mol)
Methyltriethoxysilane (MTES) 17.83 g (0.1 mol)
Tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane (FTS, carbon number 6 of perfluoroalkyl group) 7.68 g (0.0151 mol (equivalent to 7 mol% with respect to the total amount of hydrolyzable silane compound)) )
17.43 g of water
Ethanol 37.88g
A mixed solvent of 2-butanol / ethanol was added to the obtained organic / inorganic hybrid sol to prepare an organic / inorganic hybrid sol-containing alcohol solution having a solid content of 7% by mass. To 100 g of this organic-inorganic hybrid sol-containing alcohol solution, 0.35 g of an aromatic sulfonium salt (Adekaoptomer SP-150: manufactured by Asahi Denka Kogyo Co., Ltd.) as a photocationic polymerization initiator was added. Furthermore, it diluted with the mixed solvent of 2-butanol / ethanol so that solid content might be 1.0 mass%, and it was set as the coating liquid. The viscosity of the coating solution was 1 mPa · s or less when measured with a B-type viscosity type.

The obtained coating solution was applied to a rubber roller by ring coating. Thereafter, while rotating the rubber roller, irradiation was performed using a low-pressure mercury lamp (manufactured by Harrison Toshiba Lighting Co., Ltd.) so that the amount of ultraviolet light was 8000 mJ / cm ² with sensitivity at a sensor of 254 nm, and a conductive roller was obtained. .

  The film thickness of the surface layer was measured with a scanning transmission electron microscope (STEM). An organic protective film was formed on the surface of the measurement sample, sputtered Pt deposition was performed, and a smooth ion-free section was made by cutting at an acceleration voltage of 30 kV with a focused ion beam apparatus (FB-2000A type: manufactured by Hitachi). In a smooth cross section, STEM (HD-2000 type: manufactured by Hitachi) acceleration voltage 200 kV, 150 k times, was measured at any five points, and the average value was taken as the average film thickness. As a result, it was 23 nm.

  About the obtained electroconductive roller, the dispersion | variation in volume resistance and volume resistance was measured as follows, and the bleed test was done.

[Volume resistance]
Measurement was performed using a resistance measuring instrument shown in the schematic configuration diagram of FIG. The resistance measuring instrument shown in FIG. 3 is loaded with 500 g on both ends of a stainless steel cylinder 31 having a diameter of 24 mm on which the conductive roller 32 to be measured is placed and the conductive support of the conductive roller. A load device (not shown) is provided for contacting the cylinder with the cylinder. Furthermore, a bias application power source 35 for applying a bias voltage to the conductive support of the conductive roller, a fixed resistor (1 kΩ) 33 connected to the cylinder surface, and an ammeter 34 for measuring the current of the fixed resistor are provided. Provided.

  In such a resistance measuring device, the rotation speed of the cylinder was set to 30 rpm, the conductive roller was driven to rotate, and an applied voltage of −200 V was applied from the bias application power source. The measured value was sampled from the ammeter at an interval of 100 Hz, and the electric resistance was obtained as an average value for 2 seconds. The test environment was a temperature of 23 ° C. and a humidity of 50% RH. The results are shown in Table 2.

[Variation of volume resistance]
A composition similar to the conductive elastic body was cured by heating at 160 ° C. for 10 minutes using a 2 mm thick mold having a width of 100 cm ² or more to prepare a sheet-like sample. The volume resistance was measured according to the double ring electrode method of JIS K6271: 2001 by applying a voltage of −20 V between electrodes having a diameter of 10 mm, and measuring any 10 locations of the sample. Log (R _min / R _max ) was calculated with respect to the maximum value R _max and the minimum value R _{min of the} measured values, and was regarded as variation in volume resistance.

[Bleed]
The obtained conductive roller was incorporated in an LBP cartridge (toner cartridge 307: manufactured by Canon Inc.) as a charging roller and left in a constant temperature and humidity chamber at room temperature of 40 ° C. and humidity of 95% for one month. Thereafter, the cartridge was taken out from the constant temperature and humidity chamber, and the contact portion on the photosensitive member side of the contact portion between the conductive roller and the photosensitive member was observed with an optical microscope, and bleed was evaluated according to the following criteria. The results are shown in Table 2.
A: Bleed from the conductive roller is not recognized.
B: Bleeding from the conductive roller is observed, but it is a slight degree that does not affect the output image.
C: Any of deposits affecting the output image due to bleeding from the conductive roller, alteration of the photoconductor, or cracking of the photoconductor is observed.

[Image evaluation]
The obtained conductive roller and photoreceptor were incorporated into an LBP cartridge (trade name: toner cartridge 307; manufactured by Canon Inc.) and mounted on an electrophotographic apparatus (trade name: LBP5000; manufactured by Canon Inc.). Then, using the electrophotographic apparatus, a halftone (intermediate gradation) image was output under the condition that the area gradation is not performed in an environment of a temperature of 23 ° C. and a humidity of 50% RH. In the output image, no uneven density was observed, and a clear image was obtained. Normally, the halftone image output from the LBP has an area gradation as image processing in order to reduce density unevenness. However, when the area gradation is applied, the fineness of the image becomes rough.

[Example 2]
Except for changing the addition amount of the quaternary ammonium salt to 1 part by mass to 0.08 parts by mass, a conductive roller was prepared in the same manner as in Example 1, and the volume resistance, its variation, and bleed were evaluated. went. The results are shown in Table 2.

[Example 3]
Except for changing the addition amount of the quaternary ammonium salt to 3.1 parts by mass instead of 1 part by mass, a conductive roller was prepared in the same manner as in Example 1, and the volume resistance, its variation, and bleed were evaluated. went. The results are shown in Table 2.

[Example 4]
Implementation was conducted except that the quaternary ammonium salt (Adeka Coal CC-42: manufactured by Asahi Denka Kogyo Co., Ltd.) in Example 1 was changed to a quaternary ammonium salt (Adeka Coal CC-15: manufactured by Asahi Denka Kogyo Co., Ltd.). A conductive roller was produced in the same manner as in Example 1. With respect to this conductive roller, volume resistance, variation thereof, and bleed were evaluated in the same manner as in Example 1. The results are shown in Table 2. The number average molecular weight Mn of Adeka Coal CC-15 (Asahi Denka Kogyo Co., Ltd.) was 1276.

[Comparative Example 1]
Except not adding a quaternary ammonium salt, the electroconductive roller was produced by the same method as Example 1, and volume resistance, its dispersion | variation, and bleed were evaluated. The results are shown in Table 2.

[Comparative Example 2]
The conductive roller was changed in the same manner as in Example 1 except that the quaternary ammonium salt in Example 1 was changed to dimethyl dioctadecyl ammonium chloride (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 586.5 (catalog value)). Produced. With respect to this conductive roller, volume resistance, variation thereof, and bleed were evaluated in the same manner as in Example 1. The results are shown in Table 2.

  In the conductive roller of Comparative Example 1, there is no bleed because no quaternary ammonium salt is added, but the volume resistance is low and the variation in volume resistance is large. It is presumed that the low volume resistance and the large variation are caused by the aggregation of the conductive particles. For this reason, there is a concern that the yield rate may decrease during production. In the output image by the electrophotographic apparatus, there was no density unevenness when area gradation was performed, but when the area gradation was not performed, density unevenness occurred due to resistance variation.

  In the conductive roller of Comparative Example 2, since the quaternary ammonium salt was added, the volume resistance was high, the variation in volume resistance was small, and the dispersion was good, but bleeding occurred. In the output image by the electrophotographic apparatus, an image defect occurred in the circumferential cycle of the conductive roller and the photoreceptor, and an image defect due to bleeding occurred.

  In the conductive rollers of Examples 1 and 4, the quaternary ammonium salt promotes the dispersion of the conductive particles (B) because the volume resistance is higher than the conductive roller of Comparative Example 1 and the variation in volume resistance is small. Efficient production and high yield rate can be expected. In addition, in the output image by the electrophotographic apparatus, there is no occurrence of image defects due to bleeding, and it can be seen that generation of blades is suppressed when the number average molecular weight is 1000 or more even with a quaternary ammonium salt. Furthermore, in the output image by the electrophotographic apparatus, the density unevenness was not recognized even if the area gradation was not applied, so that it can be understood that the present invention can also be applied to an LBP that requires higher definition image quality. In Example 2, since the addition amount of the quaternary ammonium salt having a number average molecular weight of 1000 or more is less than 0.1 parts by weight, the variation in volume resistance is not as small as in Example 1.

  Further, when the addition amount of the quaternary ammonium salt having a number average molecular weight of 1000 or more is less than 0.1 parts by mass (Example 2) or more than 3 parts by mass (Example 3), the volume resistance slightly varies. It can be seen that although a slight blade is generated, it does not lead to an image defect.

It is a figure which shows the schematic block diagram of the roller extrusion molding apparatus of an example of the manufacturing apparatus of the electroconductive member for electrophotographic apparatuses of this invention. It is a figure which shows schematic structure figure of an example of the electroconductive member for electrophotographic apparatuses of this invention. It is a figure which shows schematic structure figure of the measuring apparatus which measures the volume resistance of the electroconductive member for electrophotographic apparatuses of this invention.

Explanation of symbols

11 Conductive Support 12 Conductive Elastic Layer (Conductive Elastic Body)
13 Surface layer

Claims (6)

An electrophotographic apparatus having a conductive elastic body containing a matrix polymer (A), electroconductive conductive particles (B), and a quaternary ammonium salt (C) having a number average molecular weight of 1000 or more on a conductive support. A conductive member for
The electroconductive member for an electrophotographic apparatus, wherein the quaternary ammonium salt (C) has a polyalkenyloxy group . The electroconductive member for an electrophotographic apparatus according to claim 1 , wherein the quaternary ammonium salt (C) is represented by the following formula (2) :

(In the formula, n represents an integer of 15 or more). The conductive elastic body is in the range of 20 parts by weight or more and 80 parts by weight or less of the conductive particles (B) and 0.1 part of the quaternary ammonium salt (C) with respect to 100 parts by weight of the matrix polymer (A). electrophotographic apparatus for conductive member according to 請 Motomeko 1 or 2 containing a mass parts to 3.0 parts by weight or less of the range. The electroconductive member for an electrophotographic apparatus according to any one of claims 1 to 3, wherein the matrix polymer (A) is acrylonitrile butadiene rubber . The electroconductive member for an electrophotographic apparatus according to any one of claims 1 to 4, wherein the conductive particles (B) are carbon black . On the conductive elastic body, a main component a polysiloxane having a fluoroalkyl group and an alkenyloxy group, any one of 請 Motomeko 1-5 that average thickness having a following surface layer 1000nm least 5nm A conductive member for an electrophotographic apparatus according to Item .

Images