JP2007105625A - Manufacturing method of electrically conductive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an electrically conductive member by which film thickness unevenness of a covering layer can be suppressed without performing a plurality of times of dip coating and without changing lifting speed of an object to be coated when forming the covering layer around the object to be coated by performing dip coating. <P>SOLUTION: The manufacturing method of the electrically conductive member having a columnar electrically conductive support and an elastic layer and the covering layer around the support comprises a process for preparing the object to be coated which at least has the elastic layer provided around the electrically conductive support and has an outside surface where a contacting angle toward water stepwise or continuously becomes smaller from one end to another end in a longitudinal direction and a dip coating process for applying a coating solution onto the outside surface of the object to be coated by dipping the object to be coated in the coating solution for forming the covering layer and then lifting the object to be coated while directing its one end downward and its another end upward. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive member such as a conductive roller used in an image forming apparatus employing an electrophotographic system such as a printer, a facsimile machine, and a copying machine.

  Conventionally, a corona charger has been used as a charging device for an electrophotographic image forming apparatus, but in recent years, instead of this, a voltage is applied while a conductive member is in contact with the photosensitive member to charge the surface of the photosensitive member. The contact charging method to be used 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 is aimed at low ozone and low power, and in particular, a roller charging method using a conductive roller as a conductive member is preferable and widely used in terms of charging stability.
In the roller charging method, a conductive elastic roller is brought into pressure contact with a member to be charged, and a voltage is applied thereto to charge the member to be charged by discharge.

  Specifically, the required photoreceptor surface potential Vd is set to the discharge start voltage (about 550 V when the conductive roller is pressed against the OPC photoreceptor (organic photoconductor)). The surface of the photoreceptor required for the purpose of improving the fluctuation of the potential due to the environment and durability fluctuation as described in Patent Document 1, or the charging method in which charging is performed by applying the added DC voltage. There is an AC charging method in which charging is performed by applying, to a contact conductive roller, a voltage in which an AC component having a peak-to-peak voltage more than twice the discharge start voltage is superimposed on a DC voltage corresponding to the potential Vd.

  This is intended to equalize the potential due to the AC voltage, and the potential of the charged body converges to the potential Vd which is the center of the peak of the AC voltage, and is not affected by disturbances such as the environment. It is an excellent method as a contact charging method.

  However, in the AC charging method, a high-voltage AC voltage that is a peak-to-peak voltage more than twice the discharge start voltage (VTH) when a DC voltage is applied is superimposed, so that an AC power supply is required in addition to the DC power supply. Incurs cost increase. Furthermore, by consuming a large amount of alternating current, the durability of the conductive roller and the photoconductor is likely to decrease.

  These are solved by the DC charging method in which only the DC voltage is applied to the conductive roller to perform charging. However, in the method in which only the DC voltage is applied to the conductive roller, the charging uniformity of the conductive roller is improved and the toner is A further level of adhesion is required. That is, in the DC charging method, the coating layer thickness unevenness, coating unevenness, roughness unevenness and the like tend to appear very easily as image defects compared to the AC charging method. In particular, control of film thickness unevenness is an extremely important item for improving charging uniformity, and a film thickness difference of several μm often leads to image defects.

  Examples of a method for forming a coating film with a conductive paint on the surface of the roller body, which is an elastic body, include a roll coating method, a spray coating method, and a dip method.

  In the roll coating method, as described in Patent Document 2, the roller body is leveled and moved up and down while rotating around a cored bar. This is a method of forming a coating film by immersing the roller body in the paint while rotating horizontally.

  However, in such a roll coating method, when the roller body is separated from the liquid surface at the end of coating, it is inevitable to form a linear unevenness in the separated portion, and it is difficult to form a uniform coating film. It is.

  The spray coating method is a method in which a coating film is formed by spraying a coating material on the surface of a roller body rotating around a core metal as described in Patent Document 3.

  However, in the spray coating method, it is basically difficult to spray the paint uniformly, and there is not a little loss of paint when spraying.

  As described in Patent Document 4, the dip method is a method in which a roller main body is vertical and immersed in a paint, and then the roller main body is pulled up to form a coating film.

The dip method has advantages such as high accuracy of film thickness in the circumferential direction of the roller, resistance to surface defects such as unevenness due to coating, and simple construction of the coating device. Is the way. However, when the roller is pulled up at a constant speed, the lower coating film when the roller body is immersed becomes thicker than the upper side. In order to correct the difference in film thickness at the time of coating, the roller body is turned upside down and the dip coating is performed again, and the roller pulling speed as described in Patent Document 5 is changed. The method is used.
JP-A-57-5048 JP-A-10-177290 Japanese Patent Laid-Open No. 5-35140 JP 60-48333 A JP-A-8-207171

  However, the method of dip coating again by turning the roller body upside down requires the installation and removal of the cap twice to prevent the coating liquid from being applied to the core metal that is not required for coating. As a result, the structure of the apparatus becomes complicated, the process becomes complicated, and the cost of the apparatus itself increases. In addition, since the wettability of the surface is different before and after the first dip coating, the difference between the upper and lower film thicknesses may not be eliminated. On the other hand, it can be said that the method of changing (gradually slowing) the roller pulling speed is a simple method without increasing the number of steps. However, in practice, the method of changing the roller pulling speed increases the coating tact time, and the influence of so-called liquid dripping cannot be suppressed, and it may be difficult to eliminate the film thickness difference between the upper and lower rollers. is there.

  An object of the present invention is to perform dip coating a plurality of times when a coating layer is formed around the coating object by immersing the coating object in a coating liquid and then performing dip coating by pulling up. Even if it is not, it is providing the manufacturing method of the electroconductive member which can suppress the film thickness nonuniformity of a coating layer, without changing the pulling-up speed of a to-be-coated article.

  As a result of intensive studies by the present inventors, in dip coating, the contact angle of the surface of the object to be coated is changed so as to decrease stepwise or continuously from the lowermost end to the uppermost end during immersion. It was revealed that the film thickness can be controlled. In the case of dip coating, generally the lower film thickness at the time of dip is large. This is largely due to so-called “drip”.

According to the present invention, in a method of manufacturing a conductive member having a columnar conductive support and an elastic layer and a coating layer around the columnar conductive support,
An object to be coated having at least an elastic layer provided around the conductive support,
A step of preparing a coated object having an outer surface in which a contact angle with water is reduced stepwise or continuously from one end to the other end in the longitudinal direction; and the coated article for coating layer formation Conductivity having a dip coating process in which the coating liquid is applied to the outer surface of the object to be coated by immersing in the working liquid and pulling the one end down and the other end up A method of manufacturing a member is provided.

The contact angle θa (°) at the position of 5% of the total length of the coated object from the upper end during dip coating on the outer surface of the coated object before the dip coating process, and the contact angle θb (°) at the center part The contact angle θc (°) at the position of 5% of the total length of the object to be coated is preferably in the following relationship from the lower end during dip coating.
θc−θa ≧ 10,
θa ≦ 90 and θa <θb <θc.

  The conductive member may be a conductive roller.

  According to the present invention, when the coating layer is formed around the coating object by immersing the coating object in the coating liquid and then performing dip coating by pulling up, a plurality of dip coatings are performed. Even if it is not, the manufacturing method of the electroconductive member which can suppress the film thickness nonuniformity of a coating layer is provided, without changing the pulling-up speed of a to-be-coated article.

  According to the present invention, a conductive member having a columnar conductive support and an elastic layer and a covering layer around it can be manufactured. Examples of the columnar shape include a cylindrical shape, an elliptical columnar shape, a triangular columnar shape, a polygonal columnar shape such as a quadrangular columnar shape, and a hexagonal columnar shape. When the conductive member is a conductive roller, typically, an elastic layer and a covering layer are annularly provided in this order on the outer periphery of a cylindrical conductive support.

  Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings, taking as an example a conductive roller that can be used as a charging device of an electrophotographic image forming apparatus as the conductive member. It is not limited by.

(1) Conductive member The conductive roller has a conductive support, an elastic layer integrally formed on the outer periphery thereof, and a coating layer formed on the outer periphery thereof. The covering layer is a layer that covers at least the outer peripheral surface of the elastic layer, and as described below, a surface layer disposed on the outermost periphery, and a resistance disposed as necessary between the elastic layer and the surface layer. Including layers.

  For example, the conductive roller may have a two-layer structure including an elastic layer 2 and a surface layer 3 as a covering layer as shown in FIG. Moreover, as shown in FIG. 2, you may have a 3 layer structure which consists of the elastic layer 2, the resistance layer 4 as a coating layer, and the surface layer 3. As shown in FIG. Alternatively, as shown in FIG. 3, it may have a four-layer structure in which a second resistance layer 5 is further provided between the resistance layer 4 and the surface layer 3 as a covering layer, and another layer is an elastic layer. You may have a structure of five layers or more provided between the surface layers.

  As the electroconductive support body 1 used for this invention, the well-known electroconductive support body used for an electroconductive roller can be used suitably. For example, 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 rust prevention and scratch resistance as long as the conductivity is not impaired.

  In the conductive member, the elastic layer 2 has appropriate conductivity and elasticity in order to supply power to the electrophotographic photosensitive member as a member to be charged and to ensure good uniform adhesion to the electrophotographic photosensitive member. Further, in order to ensure uniform adhesion between the conductive member and the electrophotographic photosensitive member, it is preferable to form the elastic layer 2 in a so-called crown shape by polishing so that the central portion is thickest and narrows toward both ends. . A generally used conductive member applies a predetermined pressing force to both end portions of the support 1 to come into contact with the electrophotographic photosensitive member, so that the pressing force at the central portion is small and the both end portions become larger. The straightness of the conductive member only needs to be excellent, but if not, density unevenness may occur in the images corresponding to the center and both ends. The crown shape is preferable because this can be prevented excellently.

The conductivity of the elastic layer 2 is such that 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. The conductive agent is preferably adjusted to 10 ² Ωcm to ^{10 10} Ωcm by appropriately adding a conductive agent. As a specific elastic material of the elastic layer 2, a known elastic material used for a conductive roller can be used. For example, natural rubber, ethylene propylene rubber (EPDM), styrene butadiene rubber (SBR), silicon rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR), nitrile butadiene rubber (NBR) and chloroprene rubber (CR) And other synthetic rubbers, as well as polyamide resins, polyurethane resins and silicone resins.

  Since the surface layer 3 is formed at a position in contact with the elastic layer, the entire surface of the conductive roller is used for the purpose of preventing bleeding out of the surface of the conductive roller such as softening oil or plasticizer contained in the elastic layer. It is provided for the purpose of adjusting the electrical resistance. Further, the surface layer 3 is made of a material that does not contaminate the photosensitive member because it forms the surface of the conductive roller and comes into contact with the photosensitive member that is a member to be charged.

  As the binder resin material of the surface layer 3, a known binder resin material used for a conductive roller can be used. For example, fluorine resin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene-butylene-olefin copolymer (SEBC), olefin-ethylene-butylene-olefin copolymer (CEBC), and the like. It is done. In addition, solid binders such as graphite, mica, molybdenum disulfide, and fluorine resin powder, fluorine-based surfactant, wax, silicone oil, or the like may be added to these binder resins.

For the surface layer 3, various conductive agents (conductive carbon, graphite, copper, aluminum, nickel, iron powder, conductive tin oxide which is a metal oxide, conductive titanium oxide, or the like) can be used as appropriate. 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 resistance value of the surface layer is preferably 10 ⁴ to 10 ¹⁵ Ωcm.

  The resistance layers 4 and 5 are provided when the surface layer 3 alone is difficult to adjust the bleed out to the surface of the charging member such as softening oil or plasticizer contained in the elastic layer or the electrical resistance of the entire conductive member. It is preferable.

  As a material constituting the resistance layers 4 and 5, a known elastic material used for the resistance layer of the conductive roller can be used. For example, epichlorohydrin rubber, NBR, 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, Examples thereof include an ethylene vinyl acetate thermoplastic elastomer, a polyvinyl chloride thermoplastic elastomer, and a chlorinated polyethylene thermoplastic elastomer.

  The resistance layers 4 and 5 have conductivity. As a conductive material for developing conductivity, conductive agents (conductive carbon, graphite, conductive metal oxide, copper, aluminum, nickel, iron powder, etc.) having various electron conduction mechanisms can be used.

  In the present invention, the coating layer is formed on the outer surface of the object to be coated using the dip coating method. Specifically, the object to be coated is immersed in a coating liquid for forming a coating layer, with the end with the large contact angle on the bottom, the end with the small contact angle on the top, and pulled upward vertically, A dip coating process is performed in which the coating liquid is applied to the outer surface of the workpiece (the outer peripheral surface of the roller).

  An object to be coated is an elastic layer when a coating layer is provided on the elastic layer by dip coating. When one or more coating layers are already provided on the elastic layer, and further a coating layer is provided thereon by dip coating, what is provided with the one or more coating layers provided on the elastic layer is the article to be coated. .

  The coating layer can be formed by drying and / or curing the coating film obtained in the dip coating process as necessary.

(2) Contact angle adjustment for uniform film thickness In order to adjust the surface property (contact angle) of an object to be coated in the present invention, the contact angle can be changed without impairing the shape of the object to be coated. A method that can be used can be adopted as appropriate. For example, UV irradiation, solvent cleaning, water cleaning, tape cleaning and the like can be employed. In production, a method in which the contact angle can be changed by changing the conditions by one method is preferable.

  As an example, water cleaning of the surface of an object to be coated by a water injection device that injects water from a cleaning nozzle will be described below. In the case of water cleaning, the cleaning time on the lower side (side where the contact angle is relatively increased) is lengthened when the dip is pulled up, and the cleaning time is shortened as going to the upper side (side where the contact angle is relatively reduced) when dip is pulled up. By proceeding, the contact angle of the object to be coated with water can be decreased stepwise or continuously from the lower side toward the upper side.

For example, specifically, while rotating the elastic layer at 10 s ⁻¹ , the pressure of the jet water is 0.1 MpaG to 2 MpaG (G in pressure unit means gauge pressure), and the flow rate is 4 L / min to 12 L / min. The moving speed of the cleaning nozzle is stepwise from 0.008 to 0.05 m / sec at the lowermost end during dip coating and 0.05 to 0.1 m / sec at the uppermost end during dip coating. Alternatively, it is desirable that the contact angle is continuously increased and the contact angle is decreased stepwise or continuously as it goes from the lowermost end to the uppermost end during dip coating.

  Examples of water used for water washing include ion exchange water, purified water, ultrapure water, alkali ion water, superreducible water, tap water, and well water.

  Hereinafter, the present invention will be described in more detail using specific examples, but the present invention is not limited thereto. In addition, "part" in an Example shows a mass part.

[Example 1]
A conductive roller (charging roller) as a conductive member of the present invention was prepared in the following manner.

(Elastic layer)
Epichlorohydrin rubber: 100 parts,
Quaternary ammonium salt: 2 parts
Calcium carbonate: 30 parts
Zinc oxide: 5 parts
Fatty acid: 5 parts.

  After kneading the above materials for 10 minutes with a closed mixer adjusted to 60 ° C., add 15 parts of an ether ester plasticizer to 100 parts of epichlorohydrin rubber, and knead for another 20 minutes with a closed mixer cooled to 20 ° C. The raw material compound was adjusted. In this compound, 100 parts of raw rubber epichlorohydrin rubber, 1 part of sulfur as a vulcanizing agent, 1 part of Noxeller DM (trade name, manufactured by Ouchi Shinsei Chemical Co., Ltd.) and Noxeller TS (trade name. Inner Shinsei Chemical Co., Ltd.) 0.5 parts was added and kneaded for 10 minutes in a two-roll mill cooled to 20 ° C. The obtained compound is molded around an electroconductive support (stainless steel round bar having an outer diameter of 6 mm and a length of 260 mm) by an extrusion molding machine, heated and vulcanized, and polished to an outer diameter of 12 mm. By processing, an elastic layer having a roller shape (annular shape having an inner diameter of 6 mm, an outer diameter of 12 mm, and a length of 230 mm) was formed.

(Surface layer)
The surface layer to be coated on the elastic layer was produced as follows. As a material of the surface layer 3,
Acrylic polyol solution (active ingredient 70% by mass, xylene 30% by mass as a diluent solvent): 100 parts,
Isocyanate A (IPDI (isophorone diisocyanate)) (active ingredient 60% by mass, n-butyl acetate 15% by mass as xylene solvent, xylene 25% by mass): 40 parts,
Isocyanate B (HDI (hexamethylene diisocyanate)) (active ingredient 80% by mass, containing 20% ethyl acetate as diluent): 30 parts,
Carbon black: 80 parts
Polymethylmethacrylate (PMMA) (resin particles 8 μm): 35 parts,
Methyl isobutyl ketone: 340 parts were stirred using a mixer to prepare a mixed solution. Subsequently, the mixed solution was subjected to dispersion treatment (treatment speed 600 ml / min) using a circulation type bead mill disperser to obtain a surface layer forming coating solution.

(Adjusting the contact angle by washing with water)
The elastic layer is rotated at 10 s ⁻¹ while supporting both ends of the conductive support on which the elastic layer is formed, and high pressure water is sprayed on the outer peripheral surface of the elastic layer along the longitudinal direction of the elastic layer before coating. Next, air was blown in the same manner to remove moisture on the surface. During water washing, the pressure of high-pressure water sprayed from the nozzle was fixed at 0.5 MPaG and the flow rate was fixed at 4 L / min. Moreover, the moving speed of the high-pressure water nozzle at one end in the longitudinal direction of the elastic layer (the lowest end when dipping and lifting; 2c in FIG. 4) is 0.05 m / s, and the high pressure at the other end (the highest end when dipping and pulling up; 2a in FIG. 4). The moving speed of the water nozzle was set to 0.08 m / s, and the moving speed was set to increase continuously and uniformly (linearly) from one end to the other end.

  10 minutes after the end of air blow, the contact angle θa 10 mm inside from the other end (2a in FIG. 4) of the outer peripheral surface of the elastic body, the contact angle θb at the center (2b in FIG. 4) between the one end and the other end, When the contact angle θc inside 11.5 mm from one end (2c in FIG. 4) was measured, θa = 71 °, θb = 76 °, and θc = 82 °. Since the total length of the object to be coated (elastic layer) is 230 mm, the measurement position of θa is 5% of the total length of the object to be coated from the upper end during dip coating, and the measurement position of θc is dip coating. The position is 5% of the total length of the object to be coated from the lower end.

  The contact angle was dropped at a location where water droplets were to be measured, and measured using a contact angle meter (CA-X type, manufactured by Kyowa Interface Chemical Co., Ltd.).

(Dip coating)
As shown in FIG. 4, the surface layer forming coating solution 6 was placed in a dip coating tank 7. Then, the stainless steel support body with the elastic body, whose contact angle has been adjusted, is held in a state perpendicular to the surface of the coating liquid in the tank, and the roller-shaped elastic body, which is the object to be coated, is applied. After dipping in the working solution, it was pulled up to form a coating film of the coating solution. The pulling speed at this time was 8 mm / sec. At this time, a masking cap made of polyacetal was put on the support portion 1a protruding downward from the elastic layer.

(Dry curing)
Subsequently, the coating film was dried and cured by a batch reaction at 160 ° C. (the curing temperature of the binder resin (urethane resin) was 130 ° C.) in a batch hot air dryer, and the surface layer was coated. A sex roller was obtained.

(Film thickness measurement)
About the obtained surface layer, from one end in the longitudinal direction (upper end at the time of immersion pulling up; 2a in FIG. 4) from the average thickness ta 10 mm inside, from the other end in the longitudinal direction (the lower end at the time of immersion pulling up; 2c in FIG. 4) The average thickness tc inside 10 mm and the average thickness tb at the center (2b in FIG. 4) between the one end and the other end were measured. In the measurement, the elastic layer and the surface layer were cut out integrally at each position and observed with an electron microscope, and the film thickness average values at 10 locations were obtained.

  The difference between the maximum value and the minimum value of ta, tb, and tc was less than 3 μm, and the difference was 3 μm or more.

  Table 1 shows the contact angle of the roller-like elastic body, which is the object to be coated, and the film thickness measurement results of the surface layer coated on the conductive roller after dip coating.

[Example 2]
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 8 L / min, and the moving speed of the high-pressure water nozzle is 0.03 m / s to 0.05 m / s continuously (linearly) from the bottom end to the top end during immersion. A roller-shaped elastic body having an upper surface portion θa = 90 °, a central portion θb = 94 °, and a lower end portion θc = 100 ° is prepared as an object to be coated. A conductive roller was produced in the same manner as in Example 1 except that it was used, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

Example 3
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 2 L / min, and the moving speed of the high-pressure water nozzle is 0.02 m / s to 0.1 m / s continuously (linearly) from the bottom end to the top end during immersion. A roller-shaped elastic body having an upper surface θa = 60 °, a central portion θb = 77 °, and a lower end θc = 90 ° is prepared as an object to be coated. A conductive roller was produced in the same manner as in Example 1 except that it was used, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

Example 4
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 8 L / min, and the moving speed of the high-pressure water nozzle is 0.008 m / s to 0.05 m / s continuously (linearly) from the bottom end to the top end during immersion. A roller-shaped elastic body in which the contact angle with respect to the water on the surface of the elastic layer is an upper end portion θa = 87 °, a central portion θb = 105 °, and a lower end portion θc = 119 ° is prepared as an object to be coated. A conductive roller was produced in the same manner as in Example 1 except that it was used, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

Example 5
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 8 L / min, and the moving speed of the high-pressure water nozzle is 0.02 m / s to 0.04 m / s continuously (linearly) from the bottom end to the top end during immersion. A roller-shaped elastic body having a contact angle with water on the surface of the elastic layer with an upper end portion θa = 94 °, a central portion θb = 98 °, and a lower end portion θc = 108 ° is prepared as an object to be coated. A conductive roller was produced in the same manner as in Example 1 except that it was used, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

[Comparative Example 1]
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 6 L / min, and the moving speed of the high-pressure water nozzle is 0.05 m / s to 0.04 m / s continuously (linearly) from the bottom end to the top end during immersion. A roller-shaped elastic body having a contact angle with respect to water on the surface of the elastic layer, that is, an upper end portion θa = 89 °, a central portion θb = 85 °, and a lower end portion θc = 83 ° is prepared as an object to be coated. A conductive roller was produced in the same manner as in Example 1 except that it was used, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

[Comparative Example 2]
The pressure of the high-pressure water is set to 0.5 MPaG, the flow rate is 5 L / min, and the moving speed of the high-pressure water nozzle is set to 0.05 m / s (constant) from the lowermost end to the uppermost end during immersion. A roller-shaped elastic body having a contact angle of an upper end portion θa = 79 °, a central portion θb = 79 °, and a lower end portion θc = 79 ° was prepared and used in the same manner as in Example 1 except that it was used as a workpiece. The conductive roller was manufactured, and the film thickness difference in the longitudinal direction was evaluated. The results are shown in Table 1.

[Comparative Example 3]
The pressure of the high-pressure water is 0.5 MPaG, the flow rate is 8 L / min, the moving speed of the high-pressure water nozzle from 0.05 m / s to 0.2 m / s continuously (linearly) from the lowest end to the center during immersion, The moving speed of the high-pressure water nozzle is set from 0.2 m / s to 0.1 m / s continuously (linearly) from the center to the uppermost end, and the contact angle of the elastic layer surface with water is the upper end θa = A roller-shaped elastic body having a 85 ° central portion θb = 76 ° and a lower end portion θc = 100 ° was produced, and a conductive roller was produced in the same manner as in Example 1 except that it was used as an object to be coated. The film thickness difference was evaluated in the direction, and the results are shown in Table 1.

  The conductive member obtained by the present invention is suitably used as a conductive member such as a conductive roller used for charging in an image forming apparatus employing an electrophotographic system such as a printer, a facsimile machine, and a copying machine. it can. In particular, it can be suitably used in the case of a DC charging method.

It is a typical sectional view for explaining an example of a conductive roller. It is a typical sectional view for explaining another example of a conductive roller. It is a typical sectional view for explaining another example of a conductive roller. It is a schematic diagram for demonstrating a dip coating process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Elastic layer 3 Covering layer (surface layer)
4 Coating layer (resistance layer)
5 Coating layer (second resistance layer)
6 Coating layer (surface layer) forming coating solution 7 Dip coating tank

Claims (3)

In a method for manufacturing a conductive member having a columnar conductive support and an elastic layer and a coating layer around the columnar conductive support,
An object to be coated having at least an elastic layer provided around the conductive support,
A step of preparing a coated object having an outer surface in which a contact angle with water is reduced stepwise or continuously from one end to the other end in the longitudinal direction; and the coated article for coating layer formation Conductivity having a dip coating process in which the coating liquid is applied to the outer surface of the object to be coated by immersing in the working liquid and pulling the one end down and the other end up Manufacturing method of member. The contact angle θa (°) at the position of 5% of the total length of the coated object from the upper end during dip coating on the outer surface of the coated object before the dip coating process, and the contact angle θb (°) at the center part The method according to claim 1, wherein the contact angle θc (°) at a position of 5% of the total length of the coated object from the lower end during dip coating has the following relationship.
θc−θa ≧ 10,
θa ≦ 90 and θa <θb <θc   The method according to claim 1, wherein the conductive member is a conductive roller.

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