JP2006231191A - Production method of conductive member, and conductive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a conductive member for forming a coating layer free of film thickness unevenness for a long period of time even if a coating liquid containing particles and resins having high adhesiveness is used and a conductive member manufactured by the method. <P>SOLUTION: The production method of the conductive member having a conductive support 2a and an elastic layer 2b and coating layer 2c-2e formed on the outer periphery thereof comprising at least a process of forming the coating layer by applying the coating liquid on the outer peripheral surface of the elastic layer, and a process of holding the liquid specific gravity constant, wherein the maximum surface roughness (Rmax) in an area coming into contact with the coating liquid of an instrument for measuring the liquid specific gravity in the process of holding the liquid specific gravity constant is ≤1 μm, and the conductive member manufactured by the method are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive member used for charging, development, transfer, cleaning, static elimination, and the like in an image forming apparatus employing an electrophotographic system such as a printer, a facsimile machine, and a copying machine, and a method for manufacturing the conductive member.

  Conventionally, the charging process in the electrophotographic process is to uniformly charge the surface of the electrophotographic photosensitive member to a predetermined polarity and potential by a corona shower generated by applying a high voltage (DC voltage 6 to 8 kV) to a metal wire. Corona chargers to be used were widely used. However, there are problems such as requiring a high voltage power source and generating a relatively large amount of ozone.

  On the other hand, a contact charging method in which a voltage is applied while a conductive member is in contact with the photosensitive member to charge the surface of the photosensitive member has been put into practical use. This is because a conductive member (charging member) as a charge supply member such as a roller type, a blade type, a brush type or a magnetic brush type is brought into contact with the photosensitive member, and a predetermined charging bias is applied to the contact charging member. The photosensitive member surface is uniformly charged to a predetermined polarity and potential.

  This charging method has the advantages of lowering the voltage of the power source and reducing the amount of ozone generated. Among these, a roller charging method using a conductive roller as a contact charging member is particularly preferably used from the viewpoint of charging stability. However, the uniformity of charging is slightly disadvantageous compared to the corona charger.

  Conventionally, in order to improve charging uniformity, an AC voltage component (AC voltage component) having a peak-to-peak voltage more than twice the charging start voltage (Vth) is added to a DC voltage corresponding to a desired surface potential Vd to be charged. An “AC charging method” is used in which a superimposed voltage (pulsating voltage; a voltage whose voltage value periodically changes with time) is applied to the contact charging member (for example, Patent Document 1).

  The purpose of this is to equalize the potential so that uniform and stable uniform charging can be obtained without causing uneven charging on the surface of the photoreceptor by superimposing an AC voltage (pulsating voltage) on the DC voltage. Thus, the potential of the member to be charged converges to the potential Vd that is the center of the peak of the AC voltage, and is not affected by disturbances such as the environment, and is an excellent method as a contact charging method.

  However, in order to superimpose a high-voltage AC voltage that is a peak-to-peak voltage that is twice or more the discharge start voltage (Vth) when a DC voltage is applied, an AC power supply is required in addition to the DC power supply, which increases the cost of the device itself. . Furthermore, there is a problem that the durability of the charging roller and the photosensitive member is liable to be reduced by consuming a large amount of alternating current.

  These problems can be solved by applying only a DC voltage to the charging roller and charging, but when only the DC voltage is applied to the charging roller, it occurs due to slight film thickness unevenness on the surface of the coating layer of the charging member. As compared with the AC charging system, uneven adhesion of dirt (external additives, etc.) on the roller surface tends to appear as an image defect.

  It is considered that the above-mentioned unevenness in dirt adhesion occurs because minute unevenness in hardness occurs due to unevenness in film thickness and the contact pressure with the photosensitive member becomes non-uniform.

  As a general method for forming a coating layer, a dip coating method, which is excellent for forming a uniform coating layer, is mainly used, and a film of several μm to several tens of μm is often formed. Although this coating layer has the effect of preventing uneven charging, since the coating layer is formed using a coating solution, the concentration and temperature of the coating solution, the surface temperature of the substrate, and the environmental temperature of the coating process If the thickness is not sufficiently controlled, film thickness unevenness is likely to occur.

  On the other hand, it is clear from the examination so far that it is possible to reduce the hardness unevenness due to uneven coating on the surface of the conductive member by controlling the liquid temperature and liquid specific gravity of the coating liquid constant. It has become. However, when a coating liquid containing highly adherent particles or resin was used as the coating liquid, the particle or resin adhered to the surface of the part that was in contact with the coating liquid of the device for measuring the specific gravity, and measured. There is a problem that a deviation occurs between the liquid specific gravity and the actual liquid specific gravity, making it impossible to control the film thickness by precise specific gravity management.

As described above, this method is not necessarily appropriate when a coating liquid containing particles or resin having high adhesion is used.
JP 63-149669 (page 2)

  As described above, in the electrophotographic technology, due to the recent demand for higher image quality in the market, even the uneven resistance caused by the uneven film thickness as described above becomes poorly charged and appears as uneven color density on the image. . It has become an important issue to be solved in order to satisfy these requirements, and further level up is necessary.

  The object of the present invention has been made in view of the above problems, and when a coating layer of a conductive member is formed by applying a coating liquid, a coating liquid containing particles or resin with high adhesion is formed. Even if it uses, it is providing the manufacturing method of the electroconductive member which forms a coating layer without a film thickness nonuniformity over a long term, and the electroconductive member manufactured by this method.

  In accordance with the present invention, there is provided a method for producing a conductive member comprising a conductive support and an elastic layer and a coating layer formed on the outer periphery thereof, wherein a coating liquid is applied onto the outer peripheral surface of the elastic layer. It has at least a step of forming the coating layer and a step of keeping the liquid specific gravity of the coating liquid constant, and is in contact with the coating liquid of the apparatus for measuring the liquid specific gravity in the step of keeping the liquid specific gravity constant The method for producing a conductive member is characterized in that the maximum surface roughness (Rmax) of the portion to be formed is 1 μm or less.

  According to the present invention, there is provided a conductive member manufactured by the above-described method for manufacturing a conductive member.

  As described above, according to the present invention, when the coating liquid is applied to the outer peripheral surface of the elastic layer to form the coating layer, the maximum surface roughness (Rmax) of the portion in contact with the coating liquid is 1 μm or less. Manufacture of conductive members with a coating layer that has no film thickness unevenness even when using coating liquids containing highly adherent particles and resin by controlling the specific gravity constant with a device that measures specific gravity It has become possible to provide a method and a conductive member manufactured by the method.

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

  In the following, the formation of the surface coating layer of the roller-shaped charging member will be described in detail. However, in addition to the charging member, the objects to be contacted such as the developer carrying member, the transfer member, the cleaning member, and the charge removing member are electrically controlled. The same concept can be applied to the case where the covering layer is formed in the conductive member. Furthermore, it is suitable for a DC charging roller that is considered to be stricter than the AC charging described above in the prior art, and it can be used for AC charging. There is no.

(1) Management of coating liquid When forming a surface coating layer of a conductive member by a dipping method in which a roller is immersed in the coating liquid in a vertical state, the coating liquid is used in order to obtain a coating layer with no film thickness unevenness. The prescription design is important. For example, selection of a solvent, optimization of solid content concentration, addition of a leveling agent and the like can be mentioned. However, even if a coating liquid in which a surface coating layer can be easily formed is produced, a uniform surface coating layer cannot be continuously formed unless the coating liquid is sufficiently managed.

  In general, for the management of the coating liquid, a method of managing the liquid viscosity while keeping the liquid temperature constant occupies most of the method, and is a known method. The reason for this is that when the film is formed by the dipping method, the viscosity of the coating solution is predominantly formed in the film thickness. However, when trying to control the coating liquid by viscosity, in the case of a coating liquid having a slight structural viscosity, the shear rate of the viscometer and the liquid, and the roller and coating liquid when the roller is applied Since a difference occurs in the shear rate, a case where the film thickness of the surface coating layer does not change in a form corresponding to a change in the value of the viscometer often occurs.

  On the other hand, as a result of our extensive studies, it was found that the specific gravity of the liquid and the film thickness are highly correlated. Therefore, if liquid management is performed by the method of the present invention, a surface coating layer having a continuously stable quality can be formed. In addition, if the specific gravity of the coating liquid is managed, there will be no change in value due to the difference in shear rate that occurs in viscosity management, and even if the flow rate of the coating liquid in the coating liquid circulator is changed, the specific gravity is not at all. There is no change, and the coating solution concentration can be easily managed to be constant.

  Furthermore, the coating viscosity having a high structural viscosity often changes in the structural viscosity depending on the liquid aging and storage conditions. Actually, when the viscosity of the coating liquid is controlled, the coating liquid is circulated in the coating liquid circulator and the liquid viscosity is kept constant. In coating liquids that change over time, the desired viscosity often deviates over time. At this time, the solid content concentration of the coating liquid is too low or too high, but if the solid content concentration is high, the solid content concentration can be applied by dilution with a diluent solvent. Although it can be easily returned to the liquid, when the solid concentration is low, it is extremely difficult to concentrate, and even if it can be concentrated, a considerable time is required. As described above, the coating liquid has a structural viscosity, and the liquid viscosity changes over time even when the liquid temperature is kept constant and the viscosity is controlled. Deviates from the target value, and the solid content concentration also deviates greatly. Here, when the method of the present invention is applied, the solid concentration can be made constant by managing the specific gravity while keeping the coating solution temperature constant. For changes in structural viscosity over time and changes in storage conditions, store the coating liquid until the structural viscosity is stable, or ripen by putting the coating liquid in the coating liquid circulator and aging the coating liquid. If the coating solution is managed by the method of the present invention, a surface coating layer having a stable quality can be formed continuously.

  As a measuring method of the hydrometer provided in the coating liquid circulator, a method capable of measuring the specific gravity continuously and accurately in a circulating state of the coating liquid is preferable. For example, there are a tuning fork hydrometer and an ultrasonic hydrometer, but a tuning fork hydrometer is particularly preferable in order to perform precise specific gravity management. The Baume hydrometer can measure the specific gravity with high accuracy, but it cannot output the measured value to the device to which the diluent is added in order to keep the liquid specific gravity constant. It is not preferable as a hydrometer.

  Although the specific gravity of the coating liquid is managed by the above-described method, in recent years, the coating liquid containing various functional particles and resins has been used to give various characteristics as the speed of LBP increases and the image quality increases. Because of the presence of highly adherent particles and resins when using a conventional hydrometer, the particles and resin in the coating liquid adhere to the part that comes in contact with the coating liquid, and accurate liquid specific gravity is measured. Cannot be done. On the other hand, when the maximum surface roughness (Rmax) of the part in contact with the coating liquid of the hydrometer is 1 μm or less, even when a coating liquid containing particles or resin with high adhesion is used. The coating liquid component does not adhere to the surface of the hydrometer, and the liquid specific gravity can be accurately measured. As a method for setting the maximum surface roughness (Rmax) of the hydrometer surface to 1 μm or less, it is preferable to use a polishing process such as buffing, chemical polishing and electrolytic polishing (immersion electrolytic polishing, electrolytic composite polishing). In order to uniformly control the surface roughness, it is particularly preferable to use an electrolytic composite polishing treatment.

  In the prior art, there is a method in which the liquid temperature of the coating liquid is controlled to be almost constant at a predetermined temperature within a range of 25 to 35 ° C. However, in the case of a solvent-based coating liquid, the temperature of the coating liquid is applied. If the temperature is higher than the environmental temperature of the construction process, the evaporation of the diluting solvent will be accelerated, and it will be difficult to manage the coating liquid, and the solid content concentration will become uneven on the dip liquid surface, resulting in Filming or the like occurs and uneven coating occurs. Therefore, in the present invention, the liquid temperature of the coating liquid is maintained at a constant temperature within a range of ± 2 ° C., preferably within a range of ± 0.5 ° C. with respect to a predetermined temperature at 25 ° C. or less. . By keeping the coating solution temperature constant with high accuracy in this way, not only makes it easy to control the specific gravity of the coating solution, but also the evaporation rate of the solvent from the wet film after dipping becomes constant, resulting in uneven coating. It will be difficult. Moreover, when the liquid temperature of the coating liquid is lower than 20 ° C., the viscosity of the coating liquid increases, the wet film thickness becomes thick, and the film thickness control becomes difficult, and the environmental temperature at which the coating liquid is placed is Depending on the difference, condensation may occur and moisture may be mixed into the coating solution, which may cause uneven coating. However, it goes without saying that even if the temperature is 20 ° C. or lower, the problem can be avoided by taking measures against the above-mentioned concerns, for example, by taking appropriate dehumidifying means.

  As a device that keeps the temperature of the coating liquid provided in the coating liquid circulation machine constant, circulating temperature water or temperature controller is attached to the side or lower part of the outer wall of the coating liquid tank or dip liquid tank, and the liquid temperature sensor It is not particularly limited as long as it can monitor the temperature of the coating liquid, but it must have high heating and cooling capabilities and can be controlled with high precision. The liquid temperature monitor also circulates the coating liquid. It must be able to measure accurately in the state.

  As described in the liquid temperature control, it is preferable that there is no difference with respect to the coating liquid temperature. In the present invention, since the liquid temperature of the coating liquid is maintained at a constant temperature within a range of ± 2 ° C. with respect to a predetermined temperature at 25 ° C. or less, the environmental temperature in which the coating process is placed is also within the same range. Temperature control is appropriate. For example, since the coating liquid temperature is controlled at a constant value within a range of 20 to 25 ° C., the ambient temperature is preferably as close as possible to the constant value of the coating liquid within the range of 20 to 25 ° C. It is preferable to manage within the range of the working fluid temperature ± 1.0 ° C. As the environment of the coating process, since humidity also affects the quality of the surface coating layer formed by coating, the humidity of the environment in which the coating process is placed is preferably 60% RH or less relative humidity.

  Regarding the specific gravity control of the coating liquid, the liquid temperature of the coating liquid is 25 ° C. or less, with a predetermined temperature within a range of ± 2 ° C., preferably a constant value ± 0.5 ° C. Then, it is managed at a constant specific gravity of ± 0.003. If the specific temperature of the coating liquid exceeds a certain value +0.003 while the liquid temperature is controlled to a constant value, the solid concentration of the liquid is too high and the resulting surface coating layer is thick. It will be a thing. Conversely, when the value is below a certain value −0.003, the film thickness becomes thin. In such a case, the specific gravity is made constant by adding or evaporating the diluted solvent used in the coating liquid converted using the numerical values measured by the specific gravity monitoring mechanism installed in the coating liquid circulation system. Perform the operation. If the solid content concentration of the coating liquid is controlled with specific gravity, it can be managed with extremely high accuracy. As an effective numerical value of specific gravity, it is preferable to manage the coating liquid using up to 3 digits after the decimal point.

  In order to keep the specific gravity of the coating liquid constant, a diluting liquid is added. When two or more kinds of solvents are used in the coating liquid, the solvent excluding the solvent of less than 10% by mass with respect to the total solvent. A dilution solvent is prepared at a mass ratio, and added to the coating solution as necessary. As the addition method, various pumps can be used, but those that can ensure a high-accuracy flow rate are preferable. The addition flow rate of the solvent per hour varies depending on the volatilization rate of the solvent, that is, the size of the coating liquid circulation device and the coating dip liquid-salt area, but a non-pulsation pump or the like whose difference in instantaneous flow rate is as small as possible is preferable.

  In addition, as the place where the diluent is added, it is preferable that the coating liquid as uniform as possible is in the dip liquid tank. Therefore, the place where the diluent is added is determined based on the circulation path of the coating liquid. It is more advantageous to add to the overflowing coating solution. That is, since a certain time is required until the coating liquid reaches the dip liquid tank after the dilution liquid is added to the coating liquid, a more uniform coating liquid is supplied to the dip liquid tank. However, when adding the diluent to the coating solution, there is a concern about aggregation of pigment particles added due to solvent shock, so the place where the diluent solvent is added to the coating solution is as much as possible. It is necessary to provide a place where the fluid velocity is large and the diluent is instantaneously mixed with the coating solution. In this way, the place where the diluent is added may be added to the portion of the circulation system where the fluid velocity of the coating solution is as large as possible between the portion overflowing from the dip solution tank and the coating solution tank. In order to keep the coating solution uniform, it is preferable.

(2) Conductive Member For example, the conductive member has a roller shape as shown in FIG. 1, and includes a conductive support 2a and an elastic layer 2b integrally formed on the outer periphery thereof as a covering layer.

  Another configuration of the conductive member of the present invention is shown in FIG. As shown in FIG. 2, the conductive member may be a two-layer coating layer composed of an elastic layer 2b and a surface layer 2c, a three-layer layer composed of an elastic layer 2b, a resistance layer 2d and a surface layer 2c, and a resistance layer. It is good also as a structure which formed four or more layers which provided the 2nd resistance layer 2e between the layer 2d and the surface layer 2c on the electroconductive support body 2a.

  As the conductive support 2a used in the present invention, a round bar made of a metal material such as iron, copper, stainless steel, aluminum and nickel can be used. Furthermore, these metal surfaces may be plated for the purpose of providing rust prevention and scratch resistance, but it is necessary not to impair the conductivity.

The conductivity of the elastic layer 2b has a conductive agent having an electron conduction mechanism such as carbon black, graphite and a conductive metal oxide in an elastic material such as rubber, and an ion conduction mechanism such as an alkali metal salt or a quaternary ammonium salt. It is preferable to adjust to less than 10 ¹⁰ Ω · cm by appropriately adding a conductive agent. Specific elastic materials for the elastic layer 2b include, for example, natural rubber, ethylene propylene rubber (EPDM), styrene butadiene rubber (SBR), silicone rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR). ), Synthetic rubbers such as nitrile butadiene rubber (NBR) and chloroprene rubber (CR), as well as polyamide resins, polyurethane resins and silicone resins.

In a charging member that applies a direct current voltage only to charge an object to be charged, in order to achieve charging uniformity, particularly a moderate resistance polar rubber (for example, epichlorohydrin rubber, NBR, CR, urethane rubber, etc.) It is preferable to use polyurethane resin as an elastic material. These polar rubbers and polyurethane resins are considered to have a slight conductivity due to moisture and impurities in the rubber and resin as carriers, and these conduction mechanisms are considered to be ionic conduction. However, an elastic layer is prepared without adding a conductive agent to these polar rubbers and polyurethane resins, and the obtained charging member has a high resistance value in a low temperature and low humidity environment (L / L) and is not less than 10 ¹⁰ Ω · cm. Therefore, a high voltage must be applied to the charging member.

Accordingly, the conductive agent having the electronic conduction mechanism and the conductive agent having the ionic conduction mechanism described above are appropriately added and adjusted so that the resistance value of the charging member in the L / L environment is less than 10 ¹⁰ Ω · cm. preferable. A conductive agent having an ionic conduction mechanism is preferable in terms of production because resistance adjustment is easy. However, the conductive agent having an ionic conduction mechanism has a small effect of lowering the resistance value, and particularly in the L / L environment. Therefore, the resistance adjustment may be performed by supplementarily adding a conductive agent having an electronic conductive mechanism in addition to the addition of a conductive agent having an ionic conductive mechanism. The elastic layer 2b may be a foam obtained by foaming these elastic materials.

  Since the resistance layer 2d (e) is formed at a position in contact with the elastic layer, the resistance layer 2d (e) is provided for the purpose of preventing bleed-out to the surface of the charging member such as softening oil or plasticizer contained in the elastic layer. Provided for the purpose of adjusting the overall electrical resistance.

  When the coating layer is a plurality of layers (resistance layer, surface layer), examples of the material constituting the resistance layer 2d (e) include epichlorohydrin rubber, NBR, fluororesin, polyamide resin, acrylic resin, polyurethane resin, and silicone. Resin, butyral resin, polyolefin-based thermoplastic elastomer, urethane-based thermoplastic elastomer, polystyrene-based thermoplastic elastomer, fluororubber-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, polybutadiene-based thermoplastic elastomer, ethylene acetate Examples thereof include vinyl-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, and chlorinated polyethylene-based thermoplastic elastomers. These materials may be used alone or in combination of two or more, and may be a copolymer.

  The resistance layer 2d (e) needs to have conductivity or semiconductivity. In order to develop conductivity and semiconductivity, conductive agents having various electron conduction mechanisms (conductive carbon, graphite, conductive metal oxides, copper, aluminum, nickel, iron powder, etc.) or ionic conductive agents (alkaline) Metal salts and ammonium salts) can be used as appropriate. In this case, in order to obtain a desired electric resistance, two or more kinds of the various conductive agents may be used in combination. The resistance layer 2d (e) particularly preferably contains surface-treated inorganic fine particles and a conductive agent, and when the surface layer also serves as the resistance layer, the surface-treated inorganic fine particles and the conductive agent may be used. preferable.

  Further, the surface layer 2c when the coating layer is a plurality of layers (resistance layer, surface layer) constitutes the surface of the charging member, and is a material that contaminates the photoreceptor because it contacts the photoreceptor to be charged. It must not be a configuration.

  As the binder resin material for the surface layer 2c, fluorine resin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene-butylene-olefin copolymer (SEBC), and olefin-ethylene-butylene-olefin Examples thereof include a copolymer (CEBC), and in particular, a resin excellent in slipping property and releasability such as a fluororesin, an acrylic resin, a silicone resin and a urethane resin modified with fluorine, acrylic or silicone is preferable.

  For the purpose of reducing the static friction coefficient to these binder resins, solid lubricants such as graphite, mica, molybdenum disulfide and fluororesin powder, or fluorosurfactants, wax or silicone oil may be added.

  For the surface layer 2c, various conductive agents (conductive carbon, graphite, copper, aluminum, nickel, iron powder, conductive tin oxide that is a metal oxide, conductive titanium oxide, or the like) are appropriately used. In the present invention, in order to obtain a desired electric resistance, two or more kinds of the various conductive agents may be used in combination. The average particle size of the conductive agent is preferably 1.0 μm or less. If the average particle size exceeds 1.0 μm, pinhole leakage is likely to occur when pinholes exist on the photosensitive drum, which is not preferable. In addition, when the specific gravity of the conductive agent particles is heavy, if the average particle diameter exceeds 1.0 μm, the dispersion stability of the paint is deteriorated, and it is not preferable because it tends to settle in the paint.

  Moreover, it is preferable that the ratio of a electrically conductive agent and binder resin is 0.1: 1.0-2.0: 1.0 by mass ratio. If the conductive agent is less than 0.1, it is difficult to obtain the effect due to the inclusion of the conductive agent, and if it exceeds 2.0, the mechanical strength of the surface layer decreases, the layer becomes brittle, and the hardness increases. It is easy to lose flexibility.

As the inorganic fine particles contained in the coating layer, insulating inorganic fine particles are preferable. For example, oxides, double oxides, metal oxides, metals, carbon, carbon compounds, fullerenes, boron compounds, carbides, nitrides, ceramics, and the like Examples include chalcogen compounds. In the present invention, two or more kinds of the various inorganic fine particles may be used in combination. Insulating inorganic fine particles having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more are preferably used.

  As for the surface of the conductive agent, a coupling agent such as a titanium coupling agent or an alkoxysilane coupling agent and a coupling agent such as a fluoroalkylalkoxysilane coupling agent (a center metal such as silicon, titanium, aluminum and zirconium is not particularly selected. ), Or may be treated with oil, varnish, organic compound or the like.

(About surface layer coating)
As a method for producing the surface layer 2c, the aforementioned materials are added to an organic solvent to produce a coating solution. The coating liquid is put into a liquid circulator and the coating liquid is managed by the method of the present invention. The thickness of the surface layer 2c produced by the dipping method is 10 to 30 μm.

  Examples of organic solvents that can be used in the present invention include methyl isobutyl ketone, methyl ethyl ketone, acetone and cyclohexanone ketones, aromatics such as xylene and toluene, esters such as n-butyl acetate and ethyl acetate, tetrahydrofuran, and ethyl cellosolve. And ethers such as tetrahydropyran, but are not particularly limited thereto.

  When a pulverization step is added in the production of the coating liquid, a ball mill, a sand mill, a vibration mill or the like is used.

  Next, the wet surface layer 2c produced by the coating method as described above is transferred to a dryer. As the dryer, a batch type in which the conductive member is allowed to stand, a continuous type in which the conductive member is passed through the dryer, or the like can be adopted.

  Hereinafter, the present invention will be described in more detail using specific examples. In addition, "part" in an Example shows a mass part.

Example 1
The conductive member of the present invention was produced in the following manner.
-Epichlorohydrin rubber 100 parts by mass-Quaternary ammonium salt 2 parts by mass-Calcium carbonate 45 parts by mass-Zinc oxide 5 parts by mass-Fatty acid 5 parts by mass or more kneaded for 10 minutes in a closed mixer adjusted to 60 ° C, A raw material compound was prepared. To this compound, 100 parts by mass of epichlorohydrin rubber as raw material, 1 part by mass of sulfur as a vulcanizing agent, 1 part by mass of noxeller DM (dibenzothiazyl sulfide) as a vulcanization accelerator, and noxeller TS (tetramethylthiuram monosulfide) 0.5 parts by mass was added and kneaded for 10 minutes in a two-roll mill cooled to 20 ° C. The obtained compound is molded by an extrusion molding machine so as to form a roller around a φ6 mm stainless steel support, heated and steam vulcanized, and then polished to an outer diameter of φ8.5 mm. Got. The roller length was 228 mm.

Subsequently, the following materials,
Acrylic polyol solution (Daicel Chemical Industries, PLACEL DC2016)
100 parts by mass / isocyanate A (IPDI) (Degussa, VESTANAT B1370)
22 parts by mass / isocyanate B (HDI) (Asahi Kasei Chemicals, DURANATE TPA-B80E) 33 parts by mass / conductive particles (CS-Bk100Y, manufactured by Toda Kogyo Co., Ltd.) 150 IB) 18 parts by mass / PMMA particles (manufactured by Sekisui Plastics Co., Ltd., MAX-12) 21 parts by mass / modified dimethyl silicone oil (manufactured by Dow Corning Silicone, SH28PA) 1.7 parts by mass / methyl isobutyl ketone 400 A mass part was stirred using a mixer to prepare a mixed solution. Subsequently, the mixed solution was subjected to a dispersion treatment (treatment speed: 600 ml / min) using a circulation type bead mill disperser to prepare a dipping coating solution, which was adjusted to a specific gravity of 0.927 at a liquid temperature of 21.0 ° C. Thereafter, the coating solution was put into a coating solution circulator.

  The liquid temperature of the coating liquid placed in the coating liquid circulator in which the tuning fork vibration type hydrometer shown in FIG. 4 (maximum surface roughness Rmax: 1.0 μm by electrolytic composite polishing treatment) is installed in the pipe is set to dip 漕 and The temperature was adjusted to 21.0 ° C. with a temperature controller attached around the liquid tank. The liquid specific gravity at that time was 0.927, and the liquid temperature was 21.0 ± 1.0 ° C., and the liquid specific gravity was 0.927 ± 0.003 by adding or evaporating a diluting solvent as needed. The liquid specific gravity at that time was also measured with a Baume type hydrometer as shown in FIG. 5, and was 0.927, which was the same value as that of the vibration type hydrometer.

  Next, dipping was performed by hanging eight elastic layers at equal intervals on the coating pallet. This dipping process was performed 30 times to form a coating layer for 240 elastic layers. Moreover, although it took about 6 hours from the start to the end of dipping, the liquid temperature and liquid specific gravity maintained the above set values. The value measured with the Baume hydrometer was also the same as the set value.

  The same process was performed for 7 days, but the liquid temperature and liquid specific gravity maintained the above set values. The results are shown in Table 1.

  The surface layer of the produced roller was cut, the cross section was observed with an electron microscope, the film thickness was measured at 10 points in the circumferential direction, and the average was taken as the film thickness. The results are shown in Table 1.

  Further, the above-obtained roller is attached as a charging roller to the electrophotographic image forming apparatus shown in FIG. 3, and in an N / N environment (temperature 23 ° C./humidity 55% RH), A4 having a printing rate of 4%. Images of 10,000 consecutive images were printed, halftone images were printed every 500 sheets, and image evaluation was visually performed for the occurrence of image defects due to the increase in resistance of the charging roller. The results are shown in Table 1. However, at the beginning of the image printing durability test, the printing voltage (DC voltage only) was set so that the dark portion potential Vd of the electrophotographic photosensitive member was around -400 V, and the image printing durability test was performed.

  A in the table indicates that the obtained image is very good, B is good, C indicates that the halftone image has slightly uneven density, and D indicates that the halftone image has uneven density and unevenness in density.

(Example 2)
In Example 1, except that a tuning fork vibration type hydrometer having a maximum surface roughness (Rmax) of 0.1 μm was introduced into the piping of the coating liquid circulator by electrolytic composite polishing, the same as in Example 1. A sex member was prepared. Evaluation similar to Example 1 was performed about this electroconductive member, and the result is shown in Table 1.

(Comparative Example 1)
A conductive member was produced in the same manner as in Example 1, except that a tuning fork vibration type hydrometer having a maximum surface roughness (Rmax) of 2.0 μm was introduced into the piping of the coating liquid circulator in Example 1. . Evaluation similar to Example 1 was performed about this electroconductive member, and the result is shown in Table 1.

(Comparative Example 2)
A conductive member was produced in the same manner as in Example 1 except that a tuning fork vibration type hydrometer having a maximum surface roughness (Rmax) of 10.0 μm was introduced into the piping of the coating liquid circulator in Example 1. . Evaluation similar to Example 1 was performed about this electroconductive member, and the result is shown in Table 1.

  In Examples 1 and 2, there is no deviation of the measured value from the Baume hydrometer due to the adhesion of the paint to the tuning fork hydrometer, and the liquid specific gravity is kept constant, so that repeated coating and long-term circulation are performed. In addition, a conductive member having a constant film thickness and a good durability image was obtained.

  In Comparative Examples 1 and 2, a deviation of the measured value from the Baume hydrometer occurs due to adhesion of the paint on the surface of the tuning fork hydrometer, and even if the measured value of the tuning fork hydrometer is kept constant, The film thickness changed due to the long-term circulation, and an image obtained by evaluating the durability of the member could not be obtained.

It is a schematic sectional drawing of the electroconductive member of this invention. It is a schematic sectional drawing of another electroconductive member of this invention. 1 is a schematic configuration diagram of an image forming apparatus including a conductive member of the present invention as a charging member. It is a schematic block diagram of the liquid specific gravity measuring apparatus used by this invention. It is a schematic block diagram of a Baume type hydrometer.

Explanation of symbols

1 Image carrier (electrophotographic photoreceptor)
2 Charging member (charging roller)
2a conductive support 2b elastic layer 2c surface layer 2d resistance layer 2e resistance layer 3 exposure means 4 developing means 5 transfer means (transfer roller)
6 Cleaning means S1, S2, S3 Bias applied power supply P Transfer material H1 External output device H2 Specific gravity measuring unit B1 Specific gravity reading scale

Claims (8)

A method for producing a conductive member having a conductive support and an elastic layer and a coating layer formed on the outer periphery thereof,
At least a step of applying a coating liquid on the outer peripheral surface of the elastic layer to form the coating layer, and a step of keeping the liquid specific gravity of the coating liquid constant;
A method for producing a conductive member, characterized in that the maximum surface roughness (Rmax) of a portion in contact with the coating liquid of an apparatus for measuring liquid specific gravity in the step of keeping the liquid specific gravity constant is 1 μm or less.   The method for producing a conductive member according to claim 1, wherein a portion in contact with the coating liquid of the device for measuring the liquid specific gravity is subjected to electrolytic composite polishing treatment.   The method for producing a conductive member according to claim 1 or 2, wherein in the step of keeping the liquid specific gravity of the coating liquid constant, the liquid specific gravity of the coating liquid is managed within a range of set specific gravity ± 0.003. .   The means used in the process of managing the liquid specific gravity of the coating liquid within the range of the set specific gravity ± 0.003 is a numerical value measured by a mechanism for monitoring the specific gravity installed in the coating liquid circulator system. The manufacturing method of the electroconductive member in any one of Claims 1-3 which add or evaporate the diluted liquid of this coating liquid converted.   2. The means for adding or evaporating the diluent to the coating liquid is installed between the coating liquid tank and the place where the coating liquid overflows from the dip liquid tank. The manufacturing method of the electroconductive member in any one of -4.   The method for producing a conductive member according to claim 1, wherein the coating liquid is a solvent-based coating liquid.   The method for producing a conductive member according to claim 1, wherein the solvent coating solution is a coating solution containing particles having an average particle size of 1 μm or less.   A conductive member manufactured by the method for manufacturing a conductive member according to claim 1.

Images