JP2011248224A - Method for manufacturing conductive roller and conductive roller thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a conductive roller that enables a coated film having an uniform film thickness and excellence in smoothness to be formed on an elastic layer by preventing permeation of a coating into the elastic layer composed of a foam body, thereby being capable of securing appropriate resistance and elasticity as a roller, and a conductive roller obtained thereby.SOLUTION: The method is for manufacturing a conductive roller including a shaft 1, an elastic layer 2 composed of polyurethane foam formed on an outer periphery thereof and a coated film layer 3 of at least one layer formed on a surface of the elastic layer 2. The coated film layer is formed by the application of a coated film layer-forming coating to the surface of the elastic layer by a dipping process, and in that occasion the coated film layer-forming coating is prepared so that a solid component concentration x (mass%) and a viscosity y (mPa s) satisfy expression (1) to (3): x≤60 (1); 100≤y≤1500 (2); and y≥-80x+4500 (3).

Description

  The present invention relates to a method of manufacturing a conductive roller and a conductive roller obtained by the method (hereinafter, also simply referred to as “manufacturing method” and “roller”), and more specifically, is used in an image forming apparatus using an electrophotographic system. The present invention relates to a method for manufacturing a conductive roller and a conductive roller obtained thereby.

  In general, in an image forming apparatus using an electrophotographic system such as a copying machine, a printer, and a facsimile machine, a transfer roller, a developing roller, a toner supply roller, a charging roller, a cleaning roller, an intermediate transfer roller, and a belt are used in each image forming process. A roller having conductivity, such as a driving roller, is used.

  As such a roller member, a conventional structure in which an elastic layer made of rubber, a polymer elastomer, a polymer foam or the like provided with conductivity by blending a conductive agent on the outer periphery of a shaft is used as a basic structure. In order to obtain surface roughness, conductivity, hardness, and the like, those having a single-layer or multiple-layer coating on the outer periphery thereof are used.

  As a technique related to the improvement of the roller, for example, Patent Document 1 discloses a charging roller provided with a cored bar and a conductive elastic layer formed on the outer periphery thereof. Describes a charging roller comprising a conductive foam layer and a charging layer. In Patent Document 2, a cylindrical elastic porous body having an open cell structure is provided on the outer periphery of a shaft, and a thixotropic polymer emulsion applied to the outer peripheral surface is sprayed on the application surface of the elastic porous body. There is disclosed a toner supply roller having a gel layer which is gelated by being pressed into the elastic porous body with gas.

Japanese Patent Laid-Open No. 9-43936 (Claims, [FIG. 4], etc.) JP 2004-325690 A (Claims etc.)

  When an elastic layer made of a foam body is produced by free foaming, pores are formed on the surface. As described above, a solid (non-foamed) layer is usually provided on the outer periphery of the elastic layer for the purpose of adjusting resistance and ensuring elasticity. However, if there are large pores on the surface of the elastic layer, the solid layer paint will become porous. It may get soaked inside. If the paint penetrates into the pores, a solid layer with a uniform film thickness cannot be formed, and uniform roller resistance cannot be obtained, or the solid layer surface will swell, and the desired resistance and elasticity cannot be secured. In addition, since problems such as deterioration in adhesion to a photoreceptor or the like occur, a technique for preventing such paint from penetrating has been demanded.

  Accordingly, an object of the present invention is to solve the above-described problems and prevent the coating material from penetrating into the elastic layer made of a foam body, and has excellent surface smoothness with a uniform film thickness on the elastic layer. An object of the present invention is to provide a method for producing a conductive roller capable of forming a coating film and thereby ensuring appropriate resistance and elasticity as a roller, and a conductive roller obtained thereby.

  As a result of diligent investigation, the present inventor has adjusted the solid content concentration and viscosity of the paint for forming the coating layer to a predetermined range when forming a solid coating layer by dipping coating on the elastic layer made of foam. As a result, the present inventors have found that the above problems can be solved, and have completed the present invention.

That is, the conductive roller of the present invention includes a shaft, an elastic layer made of polyurethane foam formed on the outer periphery of the shaft, and at least one coating layer formed on the surface of the elastic layer. In the manufacturing method of the property roller,
In forming the coating layer on the surface of the elastic layer by dipping application of the coating layer-forming coating material, the coating layer-forming coating material has a solid content concentration x (mass%) and a viscosity y (mPa · s). ) Are the following formulas (1) to (3),
x ≦ 60 (1)
100 ≦ y ≦ 1500 (2)
y ≧ −80x + 4500 (3)
It is characterized by preparing so that the relationship shown by (4) may be satisfied.

  In this invention, it is preferable to provide an intermediate | middle layer and a surface layer from the inner side as said coating-film layer, and to form this intermediate | middle layer with the coating material for formation of the said coating-film layer. Moreover, it is preferable to mix | blend 0.1-10 mass parts silica with respect to 100 mass parts of resin components in the coating material for formation of the said coating-film layer. Furthermore, it is also preferable to mix a thickener with the paint for forming the coating layer.

  The conductive roller of the present invention is manufactured by the above-described method for manufacturing a conductive roller of the present invention. The conductive roller of the present invention is useful as a charging roller, for example.

  According to the present invention, it is possible to form a coating film excellent in surface smoothness with a uniform film thickness on the elastic layer by preventing the paint from penetrating into the elastic layer made of the foam body. As a result, it has become possible to realize a conductive roller manufacturing method and a conductive roller that can ensure appropriate resistance and elasticity as a roller.

It is longitudinal direction sectional drawing which shows an example of the electroconductive roller of this invention. It is longitudinal direction sectional drawing which shows the other example of the electroconductive roller of this invention. It is longitudinal direction sectional drawing which shows the other example of the electroconductive roller of this invention. It is a graph which shows the relationship between the solid content density | concentration of the coating material for coating-film layer formation of each Example and a comparative example, and a viscosity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an example of the conductive roller of the present invention. The illustrated conductive roller 10 of the present invention includes a shaft 1, an elastic layer 2 made of polyurethane foam, and a coating film layer 3 that are sequentially formed on the outer periphery thereof.

In the present invention, when the coating layer 3 is formed on the surface of the elastic layer 2 by dipping the coating layer-forming coating material, a coating material that satisfies predetermined conditions is used as the coating layer-forming coating material. There is a feature. That is, in the present invention, the solid content concentration x (mass%) and the viscosity y (mPa · s) are expressed by the following formulas (1) to (3),
x ≦ 60 (1)
100 ≦ y ≦ 1500 (2)
y ≧ −80x + 4500 (3)
The coating layer 3 is formed using the coating layer-forming coating material prepared so as to satisfy the relationship represented by the above.

  In the present invention, the coating layer-forming coating material having a solid content concentration x and a viscosity y satisfying the above conditions is used to improve the quick-drying property of the coating material so that the resin component in the coating material penetrates into the elastic layer 2. Can be suppressed. As a result, the coating layer 3 having a uniform film thickness and excellent surface smoothness can be formed on the elastic layer 2, and a conductive roller ensuring proper resistance and elasticity as a roller can be obtained. It has become possible. The present invention is particularly useful when an elastic layer made of a foam body having a surface pore diameter of about 50 μm or more is used.

  Here, the solid content concentration x of the paint is related to the solid content concentration of the resin used in the paint. A paint higher than the solid content concentration of the resin cannot be produced, but a resin having a solid content concentration exceeding 60% by mass is produced. Hateful. In addition, if the solid content concentration of the paint exceeds 60% by mass, the balance between application and drying at the time of coating layer formation cannot be achieved, and it becomes difficult to control the shape of the coating layer, resulting in swells and drooling. End up. This is considered to be because the drying speed increases as the solid content concentration increases, and thus the variation in the dry state occurs within the roller surface, leading to the occurrence of swells and drooling. Therefore, the upper limit value of the solid content concentration x of the paint is set to 60% by mass. In addition, when the viscosity y of the coating exceeds 1500 mPa · s, it is difficult to control the shape of the coating film layer 3.

  In the present invention, the coating layer 3 may be applied and formed on the elastic layer 2 using a coating layer forming coating material having a solid content concentration x and a viscosity y satisfying the above conditions. The conditions can be appropriately determined as desired and are not particularly limited. Specifically, the paint for forming a coating layer having a solid content concentration x and a viscosity y satisfying the above conditions can be selected by selecting the type of resin used in the paint and the solid content concentration, It can be prepared by adding an agent. That is, for example, the solid content concentration x of the paint can be adjusted by the solid content concentration of the resin, the amount of silica added, and the like, and the viscosity y of the paint is adjusted by the amount of thickener or silica added. be able to. Therefore, in the present invention, a resin having a low solid content can be used by appropriately adjusting the blending amount of silica or thickener in the paint.

  In this invention, when mix | blending a silica in the coating material for coating-layer formation, it is preferable that the compounding quantity shall be 0.1-10 mass parts with respect to 100 mass parts of resin components of a coating material. If the amount of silica is less than 0.1 parts by mass, the solids concentration and viscosity are not sufficiently high, and if it exceeds 10 parts by mass, the solids concentration and viscosity are too high. A paint that satisfies the above conditions cannot be obtained.

  Moreover, in this invention, when mix | blending a thickener in the coating material for coating-layer formation, it is preferable that the compounding quantity shall be 0.01-10 mass parts with respect to 100 mass parts of resin components of a coating material. If the blending amount of the thickener is less than 0.01 parts by mass, the solid content concentration and the viscosity will not be sufficiently high, and if it exceeds 10 parts by mass, the solid content concentration and the viscosity will be too high. A paint satisfying the above conditions cannot be obtained. Moreover, since the surface smoothness of the coating film layer 3 will be impaired when there are too many compounding quantities of a thickener, it is unpreferable also from this viewpoint.

  FIG. 2 is a longitudinal sectional view showing another configuration example of the conductive roller of the present invention. The illustrated conductive roller 20 includes a shaft 1 and an adhesive layer 5, an elastic layer 2, a coating layer 3, and a surface layer 4 that are sequentially formed on the outer periphery thereof. The conductive roller of the present invention comprises an elastic layer 2 and at least one coating layer 3 in order on the outer periphery of the shaft 1, but preferably on the coating layer 3 as an intermediate layer as shown in the figure. Furthermore, the coating film layer 4 as a surface layer is provided. In this case, the coating layer 3 as an intermediate layer provided on the elastic layer 2 is provided to adjust the resistance and hardness of the roller, and the coating layer 4 as a surface layer adjusts the surface roughness. To be provided. When the surface layer is not provided, the performance of each roller may be adjusted by the coating film layer 3. In the present invention, since there is no penetration of the coating layer 3 into the elastic layer 2, the surface property of the conductive roller finally obtained even when the coating layer is further laminated and coated. Is not impaired. In the present invention, as shown in the figure, an adhesive layer 5 is provided on the outer periphery of the shaft 1 prior to the formation of the elastic layer 2 so that the adhesion between the shaft 1 and the elastic layer 2 can be improved. .

  In the production method of the present invention, points other than the conditions relating to the paint for forming a coating layer can be appropriately carried out according to conventional methods and are not particularly limited. For example, first, an arbitrary additive is added to the polyurethane resin constituting the elastic layer 2, and the obtained blended material is foamed by mechanically stirring using a stirrer such as a hand mixer. Then, the elastic layer 2 can be formed on the outer periphery of the shaft 1 by dipping the foamed compounding material onto the shaft 1. By forming the elastic layer 2 by directly applying a paint to the shaft 1, the manufacturing process can be simplified and the cost can be reduced.

  Here, when the adhesive layer 5 is provided on the outer periphery of the shaft 1 prior to the formation of the elastic layer 2, a paint in which constituent materials for the adhesive layer 5 described later are dispersed or dissolved is prepared, and this paint is applied to the shaft. The adhesive layer 5 can be applied and formed by applying it to the outer periphery of 1. As a coating method, known methods such as a dipping method, a spray method, a roll coater method, a die coating method, and a ring coating method can be appropriately used. After applying a paint by these methods and drying and solidifying, the adhesive layer 5 Is formed. Among these, it is preferable to use a dipping method as a coating method.

  Next, the coating layer forming coating prepared in accordance with the above conditions is applied and formed on the elastic layer 2 in the same manner as the adhesive layer 5 to form the coating layer 3. Furthermore, a conductive roller can be manufactured by applying and forming a surface layer on the coating layer 3 in the same manner as the adhesive layer 5 as desired.

  Moreover, the conductive roller of this invention should just be manufactured by the manufacturing method of the said conductive roller of this invention, and it shall be set as the conductive roller which ensured the appropriate resistance and elasticity as a roller by this. It is something that can be done. Other specific layer configurations and materials of each layer can be appropriately configured according to a conventional method, and are not particularly limited.

  For example, as the shaft 1 used for the roller of the present invention, a metal or plastic hollow cylindrical body or solid cylindrical body can be used, but preferably a metal hollow cylindrical body or solid cylindrical body. More preferably, it is a metal hollow cylinder. Thereby, cost efficiency can be improved.

As the polyurethane resin used for the polyurethane foam constituting the elastic layer 2, a conventionally known material can be appropriately selected and used, and is not particularly limited. The foaming ratio of the polyurethane foam is not particularly limited, but is preferably 1.2 to 50 times, particularly preferably about 1.5 to 10 times, and the foam density is 0.1 to 0.7 g / About cm ³ is preferable.

A conductive agent can be added to the elastic layer 2, whereby conductivity can be imparted or adjusted to a predetermined resistance value. The conductive agent is not particularly limited, and lauryltrimethylammonium, stearylmethylammonium, octadodecyltrimethylammonium, hexadecyltrimethylammonium, modified fatty acid / dimethylethylammonium perchlorate, chlorate, borofluoride , Cationic surfactants such as quaternary ammonium salts such as halogenated benzyl salts such as sulfates, etosulphate salts, benzyl bromide salts, benzyl chloride salts, aliphatic sulfonates, higher alcohol sulfates, Anionic surfactants such as higher alcohol ethylene oxide addition sulfate, higher alcohol phosphate, higher alcohol ethylene oxide addition phosphate, higher alcohol ethylene oxide, polyethylene glycol fatty acid ester , Antistatic agents such as polyhydric alcohol fatty acid nonionic antistatic agents such as _{esters, NaClO 4, LiAsF 6, LiBF} 4, NaSCN, KSCN, such ^as NaCl Li ^+, Na +, the Periodic Table of ^{K +,} etc. Electrolytes such as Group 1 metal salts or NH ₄ ⁺ salts, conductive carbons such as ketjen black and acetylene black, rubber carbons such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT Oxidized carbon for color (ink), pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium and other metals and metal oxides, Examples thereof include conductive polymers such as polyaniline, polypyrrole, and polyacetylene. These conductive agents may be used alone or in combination of two or more. Moreover, the compounding quantity of these electrically conductive agents is suitably selected according to the kind of composition, Usually, the volume resistivity of the elastic layer 2 is 10 < ⁰ > -10 < ⁸ > ohm * cm, Preferably it is 10 < ² > -10 < ⁶ > ohm * cm. It is adjusted to become.

  In addition to the conductive agent, the elastic layer 2 may include a water-proofing agent, a wetting agent, a foaming agent, a foam stabilizer, a curing agent, a thickener, an antifoaming agent, a leveling agent, if necessary. An appropriate amount of a known additive such as a dispersant, a thixotropy imparting agent, an antiblocking agent, a crosslinking agent, or a film forming aid can be blended. Among these, as a water-resistant agent, for example, ammonium zirconium carbonate can be suitably used. By adding a water-proofing agent to the elastic layer 2, it is possible to improve the environmental dependency of the roller resistance and to suppress fluctuations in resistance due to environmental changes, and to form pores formed on the surface of the elastic layer 2. The surface property of the roller can be improved by miniaturization. The blending amount of the water-resistant agent is preferably 0.5 to 20 parts by mass, particularly 0.5 to 5 parts by mass with respect to 100 parts by mass of the polyurethane resin. If the amount of the water-resistant agent is too large, the viscosity tends to be too high and the pot life tends to decrease. On the other hand, if the amount of the water-resistant agent is too small, the desired effect may not be obtained sufficiently. However, neither is preferable. Moreover, as a wetting agent, silicone type surfactants, such as polyether modified silicone, can be used conveniently, for example. The polyether-modified silicone has a structure in which a part of the alkyl group of poly (dialkylsiloxane) is replaced with a substituent having a polyoxyalkylene group. Examples of such polyether-modified silicones include dimethylpolysiloxane polyoxyalkylene copolymers. By including a wetting agent in the elastic layer 2, in addition to obtaining the leveling effect that is the original effect of the wetting agent, it is possible to suppress the coarsening of the foamed cells and to reduce the bubble diameter, It becomes possible to control the foaming specific gravity of the paint when it is freely foamed more precisely. It is preferable that the compounding quantity of this wetting agent shall be 0.1-2 mass parts with respect to 100 mass parts of polyurethane resins. If the blending amount of the wetting agent is too large, gelation of the coating tends to occur. On the other hand, if the blending amount of the wetting agent is too small, the desired effect may not be obtained sufficiently, which is not preferable.

  The thickness of the elastic layer 2 is preferably 1.0 to 5.0 mm, and more preferably 1.0 to 3.0 mm. By setting the thickness of the elastic layer 2 in such a range, spark discharge can be prevented.

  In the present invention, the coating layer 3 provided on the elastic layer 2 is preferably formed using a water-based paint. For the water-based paint used for the coating layer 3, a known rubber or resin can be used as a material for a roller or the like. Examples of the resin include a urethane-modified acrylic resin, a polyurethane resin, an acrylic resin, an acrylic silicone resin, a polyamide resin, a fluororesin, and the like, and one or more of these can be used in combination. Also, as rubber-based water-based paints, latex such as natural rubber (NR), chloroprene rubber (CR), nitrile rubber (NBR), styrene-butadiene rubber (SBR), etc., as polyurethane-based water-based paints, ether-based, Ester and other emulsions and dispersions, acrylic resin-based water-based paints, acrylic and acrylic styrene emulsions, and fluororesin-based water-based paints include polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Polymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, tetrafluoroethylene-vinylidene fluoride copolymer, polyvinylidene fluoride, polyvinyl fluoride Etc. can be suitably used Oraido.

  In the present invention, among these, a water-based acrylic resin can be suitably used as the water-based paint. As such a water-based acrylic resin, those containing acrylonitrile and n-butyl acrylate as essential components and optionally containing other monomers are preferable. Examples of other monomers include ethyl acrylate, 2-ethylhexyl acrylate, acrylic acid, Examples include methacrylic acid. The reason why acrylonitrile and n-butyl acrylate are essential components is that they contribute to the improvement of elasticity (setting property). From this viewpoint, the amount of n-butyl acrylate is increased as much as possible, and other components It is preferable to reduce the monomer ratio of other monomer components other than the essential components. On the other hand, if the ratio of acrylonitrile is too high, the formed layer becomes hard, which is not preferable. Accordingly, the monomer ratio between acrylonitrile and n-butyl acrylate, which are essential components, is preferably in the range of 1 to 25:99 to 75, particularly 5 to 20:95 to 80 in terms of molar ratio.

  The aqueous acrylic resin preferably contains a group having active hydrogen in the molecule. Examples of the group having active hydrogen include a carboxyl group, a hydroxyl group, and an amino group, and a carboxyl group is preferable. In the present invention, the ratio of the monomer containing the group having active hydrogen is preferably in the range of 3 to 6% of the total monomer amount. In the present invention, a water-based acrylic resin having a surface acid value adjusted to 10 mg / g or more, for example, 10 to 20 mg / g is suitably obtained by setting the ratio of the monomer containing a group having active hydrogen within this range. Can be used.

In the case where the coating layer 3 is provided as an intermediate layer, the coating layer 3 is blended with a conductive agent similar to that used for the elastic layer 2 in one kind or a mixture of two or more kinds. It is necessary to adjust to the resistance value. The resistance value of the coating layer 3 is appropriately set according to the resistance value of the elastic layer 2 and the resistance value required for the roller, but is usually 1 × 10 ³ to 1 × 10 ⁸ Ω · cm, particularly Can be in the range of 1 × 10 ⁵ to 1 × 10 ⁷ Ω · cm. In this case, the blending amount of the conductive agent can be an appropriate amount that achieves this resistance value, but is usually 0.01 to 60 parts by mass with respect to 100 parts by mass of the base resin of the aqueous paint In particular, the content is preferably 1 to 30 parts by mass.

  In addition to the conductive agent and the silica and / or thickener described above, various additives can be added to the coating layer 3 without departing from the object of the present invention. For example, oxazoline-based, epoxy-based, melamine-based, guanamine-based, isocyanate-based, phenol-based cross-linking agents can be blended in appropriate amounts according to the base resin used. You may mix | blend well-known additives, such as an agent, a leveling agent, a thixotropy imparting agent, and a structural viscosity imparting agent, in an appropriate amount.

  The thickness of the coating layer 3 is appropriately selected according to the thickness of the elastic layer 2 and the form of the conductive roller, and is not particularly limited, but is usually 10 to 500 μm, particularly 50 to 300 μm. Is preferred. When the thickness of the coating layer 3 is less than 50 μm, it may be difficult to adjust a sufficient resistance value. On the other hand, when the thickness exceeds 300 μm, the thickness of the elastic layer 2 becomes relatively thin, In some cases, the roller hardness (member hardness) becomes high, or the cost becomes higher than necessary.

The coating layer 4 as a surface layer provided on the coating layer 3 can be formed using the same water-based paint as the coating layer 3. Although it does not restrict | limit in particular in the water-based coating material which forms this surface layer coating layer, The electroconductive agent (electrical resistance) of a surface layer coating layer can be provided or adjusted by adding a electrically conductive agent. There is no restriction | limiting in particular as a electrically conductive agent used in this case, The thing similar to being used for the elastic layer 2 can be used suitably by 1 type or in mixture of 2 or more types. Moreover, the compounding quantity of these electrically conductive agents is suitably selected according to the kind of composition, Usually, the volume resistivity of a surface layer coating-film layer is 1 * 10 < ⁴ > -1 * 10 < ¹² > (omega | ohm) * cm, Preferably it is 1 * 10. It is adjusted to be ⁶ to 1 × 10 ⁸ Ω · cm.

  In addition, additives, such as a crosslinking agent, a thickener, a thixotropy imparting agent, and a structural viscosity imparting agent, can be added to the water-based paint forming the surface coating layer as necessary.

  The thickness of the surface coating layer is not particularly limited, but is usually 1 to 30 μm, particularly 1 to 20 μm. If the thickness of the surface layer 3 is less than 1 μm, the durability of the roller may be inferior. On the other hand, if it exceeds 20 μm, good surface properties such as adversely affecting charging characteristics and wrinkles on the surface may be obtained. It may not be obtained.

  Further, the adhesive layer 5 can be provided as desired in order to firmly bond the shaft 1 and the elastic layer 2, and the thickness thereof can be about 1 to 100 μm. The adhesive layer 5 can be formed using, for example, a resin material such as an acrylic resin, a urethane resin, an acrylic urethane resin, a polyester resin, and a polyamide resin, and a conductive agent and other additives are added as necessary. You can also.

  FIG. 3 is a longitudinal sectional view showing still another example of the conductive roller of the present invention. When a conductive roller is used as a charging roller or the like, it is important to form a uniform contact surface in the length direction when pressed by the photosensitive drum. It has a crown shape whose diameter is larger than that of the end portion in the central portion in the longitudinal direction.

When the conductive roller has a crown shape, the crown amount representing the degree of protrusion at the center in the length direction in the cross section in the longitudinal direction of the roller is preferably 50 to 300 μm. Can be made. If the crown amount is less than 50 μm, the contact pressure in the central portion in the roller length direction becomes low. On the other hand, if the crown amount exceeds 300 μm, the central portion in the roller length direction is too strongly contacted. There is a risk of causing problems such as uneven charge amount. In the present invention, the crown amount of the conductive roller can be measured using a high precision laser measuring machine LSM-430v manufactured by Mitutoyo Corporation. With this measuring machine, the outer diameter is measured at the center of the roller and at a position of 90 mm from the center to the end, and the difference between the outer diameter of the center and the average value of the outer diameter at the positions of 90 mm in both end directions is calculated. The amount of roller crown. For example, in a conductive roller having a roller length of 250 mm, the outer diameter is measured at three points of 35 mm, 125 mm, and 215 mm from one end. At that time, assuming that the outer diameter at the 35 mm position from one end is A (mm), the outer diameter at the 125 mm position is B (mm), and the outer diameter at the 215 mm position is C (mm), the crown amount (μm) is calculated as follows. formula,
Crown amount (μm) = {B− (A + C) / 2} × 1000
Can be obtained.

  In the conductive roller of the present invention, it is preferable that the deflection (film thickness accuracy) be 70 μm or less in the entire region in the roller length direction. When a conductive roller is used as a charging roller and rotated while being in contact with the photosensitive member, if the conductive roller is shaken greatly, a gap is generated between the conductive roller and the photosensitive member, and the gap distance is further increased. Will also vary. In this case, the toner particles and the external additive remaining on the photosensitive member are liable to enter the gap and adhere to the conductive roller as unevenness. As a result, the roller surface becomes mottled and causes image defects. In the present invention, the deflection of the conductive roller can be measured using a high-precision laser measuring machine LSM-430v manufactured by Mitutoyo Corporation. With this measuring machine, the outer diameter is measured at each of five points in the roller length direction, and the average value of the differences between the maximum value and the minimum value of the outer diameter measured at each point is taken as the shake.

  The conductive roller of the present invention can be particularly suitably used as a charging roller.

Hereinafter, the present invention will be described in more detail with reference to examples.
A conductive roller having a configuration in which the elastic layer 2 and the coating layer 3 were sequentially formed on the outer periphery of the shaft 1 as shown in FIG. 1 was produced as shown below according to the formulation shown in the following table.

  First, for 100 parts by mass of water-based paint (aqueous emulsion of acrylonitrile-alkyl acrylate ester-methacrylic acid-glycidyl methacrylate copolymer), 5 parts by mass of Epocross (emulsion of oxazoline group-containing styrene-acrylic copolymer), water 10 parts by weight of dispersed carbon, 7.5 parts by weight of fine seal X-12 (hydrophilic silica), 1 part by weight of SN deformer 777 (antifoaming agent), 1 part by weight of SN wet 970 (wetting agent), UH420 (thickening agent) ) 1.6% by mass was mixed and stirred with a stirrer. The water-based paint containing each component was filtered through a mesh to remove aggregates. The adhesive layer 5 having a thickness of 100 μm was formed on the outer periphery of the shaft 1 by dipping and applying the shaft 1 to this water-based paint and heat drying.

  Next, 16 parts by mass of a foaming agent (Nopco DC-100-A, manufactured by San Nopco) and 100 parts by mass of a urethane resin (Adekabon titer HUX-950, manufactured by ADEKA) and a conductive agent (311N, 4 parts by mass of Lion Co., Ltd., 6 parts by mass of foam stabilizer (Neogen S-20D, Daiichi Kogyo Seiyaku Co., Ltd.), and curing agent (Adekabon titer HUX-SW, manufactured by ADEKA) In a container, a compounding material consisting of 20 parts by mass, 2 parts by mass of a wetting agent (SN wet 980, manufactured by San Nopco Co., Ltd.) and 0.5 parts by mass of a water-resistant agent (AZ coat 5800MT, manufactured by San Nopco Co., Ltd.) And stirred for 30 minutes using a wing. Thereafter, the mixture was stirred for 6 minutes using a commercially available hand mixer and foamed to obtain a foamed urethane water dispersion.

  The foamed urethane aqueous dispersion was dipped on the outer periphery of the shaft 1 on which the adhesive layer 5 was formed, and dried and cured in a hot air oven to form an elastic layer 2 made of polyurethane foam having a thickness of 1 mm.

  Next, a water-based paint for forming a coating layer under the conditions shown in the following table was prepared, and the obtained water-based paint was dipped on the elastic layer 2 and was 30 minutes at room temperature and 20 minutes at 110 ° C. The coating layer 3 was formed by drying to obtain each conductive roller. In FIG. 4, the graph which shows the relationship between the solid content density | concentration of the coating material for coating-film layer formation of each Example and a comparative example, and a viscosity is shown.

  About each obtained roller, the smoothness of the coating-film layer 3 surface was evaluated. As a result, there was no undulation on the appearance and the film pressure was uniform, ○, there was no undulation on the appearance, but there was a slight difference in film thickness, △, and undulation on the appearance was seen on a part of the surface. The case where the undulation was generated or the unevenness derived from the cell of the foam of the elastic layer as the base appeared due to the penetration of the paint was shown as x. The results are also shown in the table below.

＊１）水系ウレタンエマルジョン：（株）ＡＤＥＫＡ製，ＨＵＸ−２１０
＊２）水系アクリルエマルジョン：高圧ガス工業（株）製，ぺガール８５２
＊３）カーボンブラック：ライオン（株）製，３１１Ｎ
＊４）シリカ：（株）トクヤマ製，Ｘ−１２
＊５）サンノプコ（株）製，ＵＨ４２０

* 1) Water-based urethane emulsion: ADEKA Corporation, HUX-210
* 2) Water-based acrylic emulsion: Pegar 852, manufactured by High Pressure Gas Industry Co., Ltd.
* 3) Carbon black: manufactured by Lion Corporation, 311N
* 4) Silica: manufactured by Tokuyama Corporation, X-12
* 5) Sannopco, UH420

  As shown in the above table, in the roller of each example in which the solid content concentration x and the viscosity y of the paint for forming a coating layer satisfy the predetermined conditions, the coating of the coating material for forming a coating layer into the elastic layer is not soaked. It did not occur, and it was confirmed that good surface smoothness was obtained.

DESCRIPTION OF SYMBOLS 1 Shaft 2 Elastic layer 3 Coating layer 4 Surface coating layer 5 Adhesive layer 10, 20, 30 Conductive roller

Claims (6)

In a method for producing a conductive roller comprising a shaft, an elastic layer made of polyurethane foam formed on the outer periphery of the shaft, and at least one coating layer formed on the surface of the elastic layer,
In forming the coating layer on the surface of the elastic layer by dipping application of the coating layer-forming coating material, the coating layer-forming coating material has a solid content concentration x (mass%) and a viscosity y (mPa · s). ) Are the following formulas (1) to (3),
x ≦ 60 (1)
100 ≦ y ≦ 1500 (2)
y ≧ −80x + 4500 (3)
A method for producing a conductive roller, characterized by being prepared so as to satisfy the relationship shown in FIG.   The method for producing a conductive roller according to claim 1, wherein an intermediate layer and a surface layer are sequentially provided from the inside as the coating layer, and the intermediate layer is formed by a coating material for forming the coating layer.   The manufacturing method of the conductive roller of Claim 1 or 2 which mix | blends 0.1-10 mass parts silica with respect to 100 mass parts of resin components in the coating material for formation of the said coating-film layer.   The manufacturing method of the conductive roller as described in any one of Claims 1-3 which mix | blends a thickener with the coating material for formation of the said coating-film layer.   A conductive roller manufactured by the method for manufacturing a conductive roller according to claim 1.   The conductive roller according to claim 5, which is a charging roller.

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