JP5650003B2 - Conductive roller and manufacturing method thereof - Google Patents

Description

  The present invention relates to a conductive roller (hereinafter, also simply referred to as “roller”) and a method for manufacturing the same, and more specifically, various uses such as development, charging, and transfer (toner supply and cleaning) in an image forming apparatus using an electrophotographic system. In particular, the present invention relates to a conductive roller suitable as a developing roller or a charging roller and a method for manufacturing the same.

  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.

  Conventionally, as a roller member used as a developing roller, a charging roller, a transfer roller (toner supply, cleaning) or the like, a conductive rubber or a polymer provided with conductivity by blending a conductive agent on the outer periphery of the shaft. Using a structure with an elastic layer made of elastomer, polymer foam, etc. as a basic structure, to obtain the desired surface roughness, conductivity, hardness, etc., one with one or more coatings on its outer periphery is used Has been.

  In addition, Patent Document 1 discloses that the use of pores has a compression layer on a mandrel for the purpose of suppressing color misregistration due to an increase in perimeter, and micropores are formed to form pores in the compression layer. Techniques for injecting balloons are disclosed. Further, in Patent Document 2, for the purpose of obtaining rollers having various volume resistance values excellent in elasticity, the surface is made of a polymer material containing a resin sphere encapsulating low-boiling hydrocarbons, A roller in which a part of a resin sphere of a layer is cut is disclosed. Furthermore, in Patent Document 3, for the purpose of providing a highly durable fixing device roller having a stable thermal conductivity and a small change in hardness and outside diameter, a resin microballoon is provided on the peripheral surface of the metal core. A fuser roller provided with at least one silicone rubber elastic layer is disclosed.

JP 2001-159852 A (claims, paragraph [0017], etc.) Japanese Patent No. 3544802 (Claims etc.) JP 2002-268434 A (claims, etc.)

  However, since all of the techniques described in Patent Documents 1 to 3 are obtained by embedding pores or resin microballoons in a solid such as a seamless tube, a foam, or silicone rubber, the thickness of the layer is more than a certain level. is necessary. For this reason, the techniques described in Patent Documents 1 to 3 cannot reduce the thickness of the elastic layer and the like, and the problem of “roller downsizing” that is indispensable for the downsizing of printers that has been increasingly demanded in recent years. Cannot be achieved.

  In order to reduce the size of the roller, it is essential to reduce the roller diameter, especially the elastic layer thickness. As a countermeasure, solids such as seamless tubes, foams, and silicone rubber should be used. Instead of laminating on the shaft, a method of drying after applying a water-based paint to the shaft can be considered. However, in order to ensure the film thickness of the elastic layer only by applying the paint, there is a problem that the coating must be repeated many times. Furthermore, if the elastic layer is thin, a discharge occurs between the shaft and the photosensitive drum, which may destroy the photosensitive drum or cause a charging failure. In addition, when manufacturing a roller, it is common to make a shape by die or polishing. However, when using a die, the die itself must be changed to change the shape. It takes time, effort, and cost. Furthermore, when polishing is performed, the shape can be changed relatively easily. However, since polishing time is required, many polishing machines are required for mass production, and there is a problem that capital investment costs are required.

  Accordingly, an object of the present invention is to provide a conductive roller that can easily ensure an appropriate elastic layer thickness and a method for manufacturing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an appropriate elastic layer thickness can be easily secured by using a water-based paint containing a resin microballoon for the elastic layer. The present invention has been completed.

That is, the conductive roller of the present invention is a conductive roller comprising a shaft, an elastic layer formed on the outer periphery of the shaft, and a surface layer formed on the outer peripheral surface of the elastic layer.
The elastic layer is formed by applying a water-based paint containing a resin microballoon and then drying, and expanding the resin microballoon by heating,
The surface layer is formed by applying a water-based paint and then drying it.

  In the conductive roller of the present invention, the water-based paint of the elastic layer preferably contains a crosslinking agent. In the present invention, the ratio of the thickness of the elastic layer after inflating the resin microballoon by heating to the thickness of the elastic layer before inflating the resin microballoon by heating is 1.2 or more. It is preferable that

The method for producing a conductive roller of the present invention includes an application step (A) of applying a water-based paint containing a resin microballoon on the outer periphery of a shaft;
After the coating step (A), a drying step (B) for drying at a temperature not higher than the expansion temperature of the resin microballoon;
After the drying step, an expansion step (C) in which the membrane of the resin microballoon is expanded by heating at a temperature equal to or higher than the expansion temperature of the resin microballoon;
And a coating / drying step (D) in which a water-based paint is applied and dried after the expansion step (C).

  In the method for producing a conductive roller according to the present invention, the water-based paint in the application step (A) contains a crosslinking agent, and the crosslinking agent is added between the expansion step (C) and the application drying step (D). It is preferable to have a crosslinking step (E) for crosslinking by heating to a temperature equal to or higher than the reaction temperature. Moreover, in this invention, it is preferable to repeat the said application | coating process (A) and the said drying process (B). Furthermore, in the present invention, the ratio of the thickness of the elastic layer after the expansion step (C) to the thickness of the elastic layer before the expansion step (C) is preferably 1.2 or more.

  ADVANTAGE OF THE INVENTION According to this invention, it became possible to provide the electroconductive roller which can ensure the thickness of an appropriate elastic layer easily, and its manufacturing method.

It is sectional drawing which shows an example of the electroconductive roller which concerns on suitable embodiment of this invention. It is an expanded sectional view showing an example of a conductive roller concerning a suitable embodiment of the present invention. It is sectional drawing which shows another example of the electroconductive roller which concerns on suitable embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a conductive roller according to a preferred embodiment of the present invention. The conductive roller 10 of the present invention includes a shaft 1, an elastic layer 2 formed on the outer periphery of the shaft 1, and a surface layer 3 formed on the outer peripheral surface of the elastic layer 2.

  FIG. 2 is an enlarged sectional view showing an example of a conductive roller according to a preferred embodiment of the present invention. In the present invention, the elastic layer 2 is formed by applying a water-based paint containing the resin-made microballoon 4 and then drying, and expanding the resin-made microballoon 4 by heating, and the surface layer 3 is dried after applying the water-based paint. It is important that they are formed. The elastic layer 2 is not formed by laminating a solid such as a seamless tube, foam, or silicone rubber on the shaft, but is coated with a water-based paint mixed with a resin microballoon 4 and then dried and expanded to form the elastic layer 2. By forming, an appropriate film thickness can be easily secured.

  In the conductive roller of the present invention, the water-based paint used for forming the elastic layer 2 preferably contains a crosslinking agent. By adding a cross-linking agent to such a water-based paint, compression set is improved. Here, the compression set indicates, for example, how much it returns to its original shape by releasing the force after continuously applying pressure to the elastic layer 2.

Next, the manufacturing method of the electroconductive roller of this invention is demonstrated.
The conductive roller manufacturing method of the present invention includes a coating step (A) for applying a water-based paint containing a resin microballoon on the outer periphery of the shaft, and an expansion temperature of the resin microballoon below the coating step (A). A drying step (B) for drying at a temperature, an expansion step (C) for inflating the membrane of the resin microballoon by heating at a temperature equal to or higher than the expansion temperature of the resin microballoon after the drying step (B), and an expansion step (C) Thereafter, there is an application drying step (D) in which a water-based paint is applied and dried. By using the water-based paint, the paint can be thinly applied on the shaft 1, and by further expanding the resin microballoon, the film thickness of the elastic layer 2 can be easily ensured to an appropriate thickness.

  In the method for producing a conductive roller of the present invention, the water-based paint in the coating step (A) contains a crosslinking agent, and the reaction temperature of the crosslinking agent is higher than the reaction temperature of the crosslinking agent between the expansion step (C) and the coating drying step (D). It is preferable to have a crosslinking step (E) in which crosslinking is carried out by heating to a temperature of. By selecting the crosslinking agent and the resin microballoon so that the reaction temperature of the crosslinking agent is higher than the expansion temperature of the resin microballoon, both expansion and compression set can be achieved. Specifically, first, the resin microballoon is heated at a temperature equal to or higher than the expansion temperature of the resin microballoon below the crosslinker reaction temperature, and then the resin microballoon is expanded to the crosslinker reaction temperature to advance the crosslinking reaction. Improve compression set performance. In addition, when the crosslinking agent and the resin microballoon are selected so that the reaction temperature of the crosslinking agent is higher than the expansion temperature of the resin microballoon, the above conditions can be satisfied in a normal temperature rising process. When attempting to expand the resin microballoon above the crosslinking agent reaction temperature, the crosslinking reaction and the expansion of the resin microballoon proceed simultaneously, which may make it difficult to control the expansion rate. Further, it is not preferable to select the crosslinking agent and the resin microballoon so that the reaction temperature of the crosslinking agent is lower than the expansion temperature of the resin microballoon, because the crosslinking reaction proceeds first and the expansion does not proceed.

  Moreover, it is preferable that the manufacturing method of the electroconductive roller of this invention performs an application | coating process (A) and a drying process (B) repeatedly. The coating step (A) to the expansion step (C) can be repeated, but the method of repeatedly applying the coating step (A) and the drying step (B) and then heating and expanding in the expansion step (C) is more preferable. A good expansion rate can be obtained. Also, the coating step (A) and the drying step (B) are repeated several times to obtain a certain film thickness, and then heated at a temperature equal to or higher than the expansion temperature of the resin microballoon to expand the resin microballoon membrane. Thus, a film thickness 1.1 to 2 times higher than the initial value can be secured.

  In the present invention, the number of repetitions of the coating step (A) and the drying step (B) is not particularly limited, but is preferably 2-9 times, more preferably 3-8 times, still more preferably 4 ~ 7 times. In the case of repeatedly applying a conventional water-based paint, in order to secure a film thickness of 1 mm, it has been necessary to apply 10 times or more. In the present invention, for example, a water-based paint containing a resin microballoon is 5 By repeating 6 times, a film thickness of 1 mm can be secured.

  In the present invention, the resin-made microballoon 4 that can be used for the water-based paint containing the resin-made microballoon 4 contains a low-boiling liquid in the core, and the shell (outer shell) is made of a thermoplastic resin. There is no particular limitation, for example, EXPANCEL 461DU20 (manufactured by AKZO NOBEL, core: isobutane, shell: polyvinylidene chloride-acrylonitrile copolymer), EXPANCEL 031WUF40 (manufactured by AKZO NOBEL, core: isobutane, shell: methacrylic acid- Acrylonitrile copolymer), Matsumoto Microsphere F-36 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., core: isobutane, shell: polyvinylidene chloride-acrylonitrile copolymer), Matsumoto Microsphere F-50 (Matsumoto Yushi Seiyaku ( Co., core Isobutane, Shell: methyl methacrylate - and acrylonitrile copolymer) and the like.

  Conventionally, a thermal decomposition type foaming agent is known as a foaming agent. However, when it is blended in a water-based paint, it reacts with moisture to lose its foaming function and expansion function. On the other hand, since the resin-made microballoon 4 is stable in the water-based paint, it does not change with time after blending and can maintain the expansion ability until it is heated.

  Further, when the resin microballoon 4 is inflated, it expands uniformly, so that an elastic layer can be obtained while maintaining the shape produced by painting. Compared to the shape control in the mold or polishing, the shape can be controlled in the same way even with the water-based paint containing the resin microballoon 4. Further, by expanding the water-based paint containing the resin microballoon 4, the material cost can be reduced. For example, the material cost can be reduced to about ½ by double expansion.

  In the present invention, the difference between the water-based paint usable in the elastic layer 2 and the water-based paint usable in the surface layer 3 is different only in that the water-based paint usable in the elastic layer 2 contains the resin microballoon 4. Each of the following water-based paints can be used, and the water-based paint that can be used for the elastic layer 2 and the water-based paint that can be used for the surface layer 3 may have the same composition or may be different. In addition, since the water-based paint is used in the present invention, the influence on the environment can be extremely reduced as compared with the solvent system.

  Examples of the water-based paint that can be used for the roller of the present invention include one or more selected from the group consisting of rubber-based, urethane-based, and acrylic-based materials. As rubber type, natural rubber (NR), chloroprene rubber (CR), nitrile rubber (NBR), latex such as styrene butadiene rubber (SBR), etc., as urethane type, emulsion and dispersion such as ether type, ester type, As the acrylic, an emulsion such as acrylic or acrylic styrene can be suitably used.

  A water-based acrylic resin is suitable as the water-based paint that can be used for the roller of the present invention. As the 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, and methacrylic acid. The reason why acrylonitrile and n-butyl acrylate are essential components is that they contribute to improvement of elasticity (set property). From this viewpoint, the amount of n-butyl acrylate is increased as much as possible, and other components are added. 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 elastic layer and the like become hard, which is not preferable. Therefore, the monomer ratio of acrylonitrile, which is an essential component, and n-butyl acrylate 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 used by setting the ratio of the monomer containing a group having active hydrogen within this range. be able to.

  Examples of the water-based paint that can be used in the roller of the present invention include an aqueous emulsion of acrylonitrile-alkyl acrylate ester-methacrylic acid-glycidyl methacrylate copolymer (manufactured by High Pressure Gas Industry Co., Ltd., crosslinking temperature 130 ° C.), urethane. Emulsion (Daiichi Kogyo Seiyaku Co., Ltd.), L2001 (SB latex, Asahi Kasei Chemicals Co., Ltd.), Movinyl 801 (Vinyl acetate emulsion, Nihon Synthetic Chemical Industry Co., Ltd.), Movinyl 186E (Ethylene-vinyl acetate emulsion) , Nippon Synthetic Chemical Industry Co., Ltd.), Movinyl 937F (acrylic acid-styrene emulsion, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and the like.

  The cross-linking agent that can be used in the present invention is not particularly limited as long as the reaction temperature of the cross-linking agent is higher than the expansion temperature of the resin microballoon. For example, EPOCROS (Nippon Shokubai Co., Ltd.) And oxazoline-based crosslinking agents such as oxazoline group-containing styrene-acrylic copolymer).

  As the oxazoline-based cross-linking agent, any water-soluble one can be used, but one having two or more oxazoline groups is preferable, and in particular, the oxazoline group equivalent is 300 to 1000. , Tg = -50 ° C. to 50 ° C. can be preferably used. If the oxazoline group equivalent exceeds 1000, the molecular weight becomes large and handling at room temperature becomes difficult. On the other hand, if it is less than 300, the reactivity is too high and gelation occurs, so neither is preferred. The compounding quantity of this oxazoline type crosslinking agent can be 5-50 mass parts with respect to 100 mass parts of aqueous acrylic resins.

  In addition, a conductive agent can be appropriately added to the water-based paint to impart conductivity. Examples of the conductive agent include an ionic conductive agent and an electronic conductive agent. Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (for example, lauryltrimethylammonium), hexadecyltrimethylammonium, and octadecyltrimethyl. Perchlorates such as ammonium (eg stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethylammonium, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl Ammonium salts such as sulfates, carboxylates and sulfonates, perchlorates, chlorates, hydrochlorides and odors of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium and magnesium Salts, iodate salts, fluoroboric acid salts, trifluoromethyl sulfate, and sulfonic acid salts. Examples of the electronic conductive agent include conductive carbon such as ketjen black and acetylene black; carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; for ink subjected to oxidation treatment Examples thereof include carbon, pyrolytic carbon, natural graphite, and artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel, copper, silver, and germanium. These conductive agents may be used alone or in combination of two or more. Moreover, there is no restriction | limiting in particular in the compounding quantity, Although it can select suitably as desired, For example, it shall be 1-20 mass parts with respect to 100 mass parts of resin components which comprise the elastic layer 2 and the surface layer 3. it can.

  Furthermore, other vulcanizing agents, vulcanization accelerators, anti-aging agents, and the like can be appropriately added to the water-based paint of the elastic layer 2 and the surface layer 3 as desired.

  In the present invention, the coating method for forming the elastic layer 2 and the surface layer 3 is not particularly limited, but usually the above water-based paint is prepared, and this water-based paint is used for the dipping method, spray method, roll coater method, die coating. A method of applying to the shaft 1 by a method or the like and drying and solidifying is adopted, and a dipping method is particularly preferably used. By directly applying the water-based paint to the shaft 1, the manufacturing process can be simplified.

  In the conductive roller 10 of the present invention, the elastic layer 2 preferably has a thickness of 0.8 to 1.3 mm, more preferably 0.83 to 1.00 mm, and 0.83 to 0. Even more preferably, it is .93 mm. By setting the thickness of the elastic layer 2 in such a range, spark discharge can be prevented.

  Furthermore, in the present invention, the ratio (expansion coefficient) of the thickness of the elastic layer 2 after the expansion step (C) to the thickness of the elastic layer 2 before the expansion step (C) is preferably 1.2 or more. More preferably, it is 28.1.88. By setting the expansion coefficient in such a range, the thickness of the elastic layer can be easily secured to an appropriate thickness, and the number of repetitions of the coating step (A) and the drying step (B) can be further reduced.

  In the present invention, the shaft 1 is made of metal or plastic, and can be a hollow cylinder or a solid cylinder, and is preferably a metal hollow cylinder or a solid cylinder. More preferably, it is a metal hollow cylinder. As a result, the cost can be further reduced.

  The thickness of the surface layer 3 is set according to the form of the conductive roller 10 and is not particularly limited, but is usually 1 to 30 μm, particularly 10 to 15 μm, and is less than 1 μm. The roller durability may be inferior. On the other hand, if it exceeds 30 μm, good surface properties may not be obtained, such as adversely affecting the charging characteristics or wrinkling the surface.

  FIG. 3 is a cross-sectional view showing another example of a conductive roller according to a preferred embodiment of the present invention. Since it is important to form a uniform contact surface in the length direction when pressed against the photosensitive drum, the conductive roller 20 has a crown shape in which the central portion in the length direction has a larger diameter than the end portion. Yes.

In the cross section in the length direction of the roller, the center in the length direction is projected from the end portion, and the crown amount representing the degree of the protrusion is preferably 50 to 300 μm. It can be made good. When the crown amount is less than 50 μm, the contact pressure at the central portion in the roller length direction becomes low. On the other hand, when the crown amount exceeds 300 μm, the central portion in the roller length direction is excessively contacted. In either case, the charge amount may be non-uniform. Note that the measurement of the crown amount of the conductive roller of the present invention can be performed 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 each position of 90 mm in the direction of both ends 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 (1),
Crown amount (μm) = {B− (A + C) / 2} × 1000 (1)
Can be obtained.

  In the present invention, it is preferable that the conductive rollers 10 and 20 have a deflection (film thickness accuracy) of 70 μm or less in the entire region in the roller length direction. When the conductive rollers 10 and 20 are rotated while being in contact with the photosensitive member using the charging roller, when the swinging of the conductive rollers 10 and 20 is large, the conductive rollers 10 and 20 are disposed between the photosensitive roller and the photosensitive member. A void is generated. Furthermore, the gap distance also varies. 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 rollers 10 and 20 as unevenness. Therefore, the surface of the roller becomes mottled and causes image defects. The runout means the average value of the difference between the maximum value and the minimum value of the outer diameter measured at each of the five points in the roller length direction, and the conductive roller 10 of the present invention. , 20 can be measured using a high-precision laser measuring machine LSM-430v manufactured by Mitutoyo Corporation.

Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
In accordance with the formulation shown in Table 1 below, EXPANSEL 461DU20 (unexpanded balloon (core: isobutane, shell: polychlorinated) is added to water-based paint 1 (aqueous emulsion of acrylonitrile-alkyl acrylate-methacrylic acid-glycidyl methacrylate copolymer). Vinylidene-acrylonitrile copolymer)), epocross (emulsion of oxazoline group-containing styrene-acrylic copolymer), water-dispersed carbon, fine seal X-12 (hydrophilic silica), SN deformer 777 (antifoaming agent), SN wet 970 (wetting agent) and UH420 (thickening agent) were blended and stirred with a stirrer. The water-based paint 1 containing each component was filtered through a mesh to remove aggregates. The obtained water-based paint 1 was applied to a metal shaft by dipping and dried at room temperature for 10 minutes and at 70 ° C. for 10 minutes. Thereafter, dipping coating was performed again, and coating and drying were repeated 5 times. Next, the unexpanded balloon was inflated by heating at 120 ° C. for 10 minutes, and heated at 140 ° C. for 10 minutes to carry out a crosslinking reaction. Further, a water-based paint excluding EXPANCEL 461DU20 (unexpanded balloon) from the formulation shown in Table 1 below was applied and dried at room temperature for 10 minutes and at 70 ° C. for 10 minutes to form a surface layer of 15 μm. The masking member at the end of the shaft was removed to obtain the conductive roller shown in FIG. In addition, in the following Tables 1-4, a thickener compounding quantity is shown by the mass%.

(Examples 2 to 11)
A conductive roller was obtained in the same manner as in Example 1 except that the formulation described in Tables 1 to 3 below was followed.

(Example 12)
According to the formulation of Example 1 shown in Table 1 below, the temperature was raised from 70 ° C. to 140 ° C. and heated for 20 minutes to inflate the unexpanded balloon and perform a crosslinking reaction in the same manner as in Example 1. A conductive roller was obtained.

(Comparative Example 1)
Conducting in the same manner as in Example 1 except that coating-drying was repeated 11 times in order to make the film thickness equivalent to Example 3 according to the formulation shown in Table 4 below, and a crosslinking reaction was performed at 120 ° C. for 20 minutes. A sex roller was obtained.

(Comparative Example 2)
A conductive roller was obtained in the same manner as in Example 1 except that the formulation described in Table 4 below was followed.

(Comparative Example 3)
A conductive roller was obtained in the same manner as in Example 1, except that the unexpanded balloon was inflated by heating at 145 ° C. for 20 minutes in accordance with the formulation shown in Table 4 below to perform a crosslinking reaction. The reaction temperature of the crosslinking agent is lower than the expansion temperature of the resin microballoon.

(Expansion rate)
The film thickness of the elastic layer before the expansion step (C) and the film thickness of the elastic layer after the expansion step (C) are measured, and the elasticity after the expansion step (C) with respect to the film thickness of the elastic layer before the expansion step (C) The layer thickness ratio (expansion coefficient) was determined. The results are shown in Tables 1 to 4 below.

*１：アクリロニトリル−アクリル酸アルキルエステル−メタクリル酸−メタクリル酸グリシジル共重合物の水性エマルション（高圧ガス工業（株）製、架橋温度１３０℃）
*２：ウレタンエマルション（第一工業製薬（株）製）
*３：未膨張バルーン（コア：イソブタン、シェル：ポリ塩化ビニリデン−アクリロニトリル共重合物、ＡＫＺＯ ＮＯＢＥＬ社製、膨張温度１０６℃）
*４：オキザゾリン基含有スチレン−アクリル共重合物のエマルション（日本触媒（株）製）
*５：水分散カーボン（御国色素（株）製）
*６：親水性シリカ（（株）トクヤマ製）
*７：消泡剤（サンノプコ（株）製）
*８：潤滑剤（サンノプコ（株）製）
*９：増粘剤（（株）ＡＤＥＫＡ製）

* 1: Aqueous emulsion of acrylonitrile-alkyl acrylate ester-methacrylic acid-glycidyl methacrylate copolymer (manufactured by High Pressure Gas Industry Co., Ltd., crosslinking temperature 130 ° C.)
* 2: Urethane emulsion (Daiichi Kogyo Seiyaku Co., Ltd.)
* 3: Unexpanded balloon (core: isobutane, shell: polyvinylidene chloride-acrylonitrile copolymer, manufactured by AKZO NOBEL, expansion temperature 106 ° C)
* 4: Emulsion of oxazoline group-containing styrene-acrylic copolymer (manufactured by Nippon Shokubai Co., Ltd.)
* 5: Water-dispersed carbon (manufactured by Mikuni Dye Co., Ltd.)
* 6: Hydrophilic silica (manufactured by Tokuyama Corporation)
* 7: Antifoaming agent (manufactured by San Nopco)
* 8: Lubricant (manufactured by San Nopco)
* 9: Thickener (made by ADEKA Corporation)

*１０：Ｌ２００１（ＳＢラテックス、旭化成ケミカルズ（株）製）
*１１：モビニール８０１（酢酸ビニルエマルション、日本合成化学工業（株）製）
*１２：モビニール１８６Ｅ（エチレン−酢酸ビニルエマルション、日本合成化学工業（株）製）
*１３：モビニール９３７Ｆ（アクリル酸−スチレンエマルション、日本合成化学工業（株）製）

* 10: L2001 (SB latex, manufactured by Asahi Kasei Chemicals Corporation)
* 11: Movinyl 801 (vinyl acetate emulsion, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
* 12: Movinyl 186E (ethylene-vinyl acetate emulsion, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
* 13: Mobile 937F (acrylic acid-styrene emulsion, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)

*１４：未膨張バルーン（コア：イソブタン、シェル：メタクリル酸−アクリロニトリル共重合物、ＡＫＺＯ ＮＯＢＥＬ社製、膨張温度８５℃）
*１５：未膨張バルーン（コア：イソブタン、シェル：ポリ塩化ビニリデン−アクリロニトリル共重合物、松本油脂製薬（株）製、膨張温度８０℃）
*１６：未膨張バルーン（コア：イソブタン、シェル：メチルメタクリレート−アクリロニトリル共重合物、松本油脂製薬（株）製、膨張温度１０５℃）

* 14: Unexpanded balloon (core: isobutane, shell: methacrylic acid-acrylonitrile copolymer, manufactured by AKZO NOBEL, expansion temperature 85 ° C)
* 15: Unexpanded balloon (core: isobutane, shell: polyvinylidene chloride-acrylonitrile copolymer, manufactured by Matsumoto Yushi Seiyaku Co., Ltd., expansion temperature 80 ° C)
* 16: Unexpanded balloon (core: isobutane, shell: methyl methacrylate-acrylonitrile copolymer, manufactured by Matsumoto Yushi Seiyaku Co., Ltd., expansion temperature 105 ° C)

*１７：発泡剤（ｐ，ｐ’−オキシビスベンゼンスルホニルヒドラジド、三協化成（株）製）
*１８：未膨張バルーン（コア：イソブタン、シェル：メチルメタクリレート−アクリロニトリル共重合物、松本油脂製薬（株）製、膨張温度１４０℃）

* 17: Foaming agent (p, p'-oxybisbenzenesulfonyl hydrazide, manufactured by Sankyo Kasei Co., Ltd.)
* 18: Unexpanded balloon (core: isobutane, shell: methyl methacrylate-acrylonitrile copolymer, manufactured by Matsumoto Yushi Seiyaku Co., Ltd., expansion temperature 140 ° C)

  In the conductive rollers of Examples 1 to 12, the thickness of the elastic layer could be easily secured to an appropriate thickness. Moreover, since the electroconductive roller of the comparative example 1 does not contain resin microballoons, it was necessary to repeat coating-drying 11 times, and the film thickness of the elastic layer could not be easily ensured to an appropriate thickness. Furthermore, since the conductive roller of Comparative Example 2 contained a foaming agent instead of the resin-made microballoon, it did not expand sufficiently, and the film thickness of the elastic layer could not be easily ensured to an appropriate thickness. Furthermore, in the conductive roller of Comparative Example 3, since the reaction temperature of the crosslinking agent is lower than the expansion temperature of the resin microballoon, the resin microballoon does not expand sufficiently, and the film thickness of the elastic layer is easy. It was not possible to secure an appropriate thickness.

DESCRIPTION OF SYMBOLS 1 Shaft 2 Elastic layer 3 Surface layer 4 Resin microballoons 10 and 20 Conductive roller

Claims (7)

In a conductive roller comprising a shaft, an elastic layer formed on the outer periphery of the shaft, and a surface layer formed on the outer peripheral surface of the elastic layer,
The elastic layer is formed by applying a water-based paint containing a resin microballoon and then drying, and expanding the resin microballoon by heating,
The conductive roller, wherein the surface layer is formed by applying a water-based paint and then drying.   The conductive roller according to claim 1, wherein the water-based paint of the elastic layer contains a crosslinking agent.   The ratio of the thickness of the elastic layer after inflating the resin microballoon by heating to the thickness of the elastic layer before inflating the resin microballoon by heating is 1.2 or more. The conductive roller as described. An application step (A) of applying a water-based paint containing a resin microballoon to the outer periphery of the shaft;
After the coating step (A), a drying step (B) for drying at a temperature not higher than the expansion temperature of the resin microballoon;
After the drying step (B), an expansion step (C) in which the membrane of the resin microballoon is expanded by heating at a temperature equal to or higher than the expansion temperature of the resin microballoon;
And a coating / drying step (D) in which a water-based paint is applied and dried after the expansion step (C). The water-based paint in the coating step (A) contains a crosslinking agent,
The conductive roller manufacturing method according to claim 4, further comprising a crosslinking step (E) in which the crosslinking is performed by heating to a temperature equal to or higher than the reaction temperature of the crosslinking agent between the expansion step (C) and the coating drying step (D). Method.   The method for producing a conductive roller according to claim 4 or 5, wherein the coating step (A) and the drying step (B) are repeated.   The ratio of the thickness of the elastic layer after the said expansion process (C) with respect to the thickness of the elastic layer before the said expansion process (C) is 1.2 or more, The electroconductivity as described in any one of Claims 4-6 Manufacturing method of the adhesive roller.

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